Economic and applied geology

Are geoscience job prospects about to boom?

September 2008

Metal thefts in the UK have increased to such an extent in 2008 that police are marking lead on church roofs with the same identification tags as televisions and DVD players. Similarly there has been an outbreak of filching heating oil and diesel from isolated farmsteads. This follows the surge in commodity prices during the first two quarters of 2008. On a more legal note, oil and mining companies have found that their assets have soared, and unsurprisingly they want more of the same, while the prices hold or rise even further. Exploration managers with increased budgets are set to thrust out to the frontiers, and consultants are rubbing their hands with glee. On the surface, these developments might seem to foretell a welcome rise in the employability of people with a geoscience degree; or so think three contributors to the 8 August 2008 issue of Science (Gramling, C. 2008. In the geosciences, business is booming. Science v. 321, p. 856-7. Laursen, L. 2008. Geoscientists in high demand in the oil industry Science v. 321, p. 857-9. Coontz, R. 2008. Hydrogeologists tap into demand for an irreplaceable resource. Science v. 321, p. 858-9). It is claimed that geoscience jobs in the US will rise by 22% in the next decade, compared with an overall jobs forecast around 10%. Low place-value physical resources being, by definition, potentially profitable world-wide, prospects ought to be good for ‘geos’ globally. Salaries also seem to be set to rise, along with employability for individuals with first degrees, as opposed to master’s qualifications. The ruthless downsizing, outsourcing and lay-offs of the 80s and 90s have also placed greater value on Earth science qualifications, simply because there has been a decline in students opting for seemingly moribund career prospects; a matter of increased demand facing diminished supply, as any trader at the London metal exchange or the world’s petroleum spot markets would verify. At the same time, shifts in research funding from rock-oriented geosciences to Earth system science have created a bear market for geological academic posts. High-flying geologists in universities and surveys may well be polishing up their CVs in anticipation of a growing wage differential between the public and private sectors.

Set against such rosy prospects are the inherent economic risks that are bound up with inflation in commodity prices. Historically, there has been a tendency for boom then bust in mining and the oil industry. The contrast between the surge in petroleum and metals prices following the Yon Kippur War and the Iranian Revolution and recession in the 80s and 90s being too recent to ignore, as many ‘geos’ who found themselves ‘over the hill’ in its aftermath will admit. It would be wise to look on prospects with caution. One area that is likely to rise in prominence is ‘environmental’ geology: the likes of hydrogeology; geotechnics; coastal and flood defence. The problems that global warming may bring, an increased focus on leisure learning and heritage, and the fact that around 20% of all living people have little if any access to clean drinking water and adequate standards of public hygiene compete in many ways for young geoscientists’ aspirations. On a mercenary yet acutely practical note, growing environmental legislation and provision of development funds by non-governmental agencies that range in scale from the UN ‘family’ to small charitable bodies suggest that these fields are likely to provide satisfyingly useful employment with longer-term stability than the uncontrollable vagaries of the commodity markets, albeit at somewhat more modest salaries.

Hydrocarbons from the mantle: was Gold right?

March 2008

In 1999 the late Thomas Gold, cosmologist and quite a lot more, annoyed the geoscience community with publication of his book The Deep Hot Biosphere: The Myth of Fossil Fuels (Springer-Verlag: New York). In that book Gold reached the acme of his lone campaign for recognition that oil, gas and even coal formed from carbon and hydrogen feedstock that had been residing in the mantle since the Earth’s accretion. He suggested that it was mediated by a hidden yet teeming biosphere at much deeper levels than suspected at the time. I did my share of carpet gnawing, but was sorry to learn of the death in 2004 of such a supreme scientific provocateur. Although without mentioning Gold, a recent paper hints at a possibility that he may have been on to something (Proskurowski, G. et al. 2008. Abiogenic hydrocarbon production at Lost City hydrothermal field. Science, v. 319, p. 604-607).

Hydrocarbons are often found as blobs in fluid inclusions within gangue minerals of a variety of ore bodies. The US-Swiss research team examined hydrocarbons within the fluids that gush from a hydrothermal vent at 30˚N on the Mid-Atlantic Ridge; i.e. where there is no older sediment that might host biologically generated hydrocarbons, but where heat-loving microbial life could play a role. Molecular structure and carbon-isotope composition of the hydrocarbons point strongly to their formation by reduction of CO2 to methane and low molecular weight hydrocarbons by the catalytic action of mineral surfaces in the presence of a great deal of hydrogen. This is known as a Fischer-Tropsch reaction, the basis for making oil from coal, as in Nazi Germany and South Africa when under economic blockade.

The CO2 could have come from two possible sources: seawater or the mantle beneath the Lost City vents. Hydrogen can form abundantly when the olivine in peridotite beaks down to serpentinite as seawater is convected through the oceanic mantle. The vents have created towers made partly of carbonates, in whose pores there are microbes whose metabolism is based on use of hydrogen. However, the key finding is that the hydrocarbons contain no radioactive 14C, which forms by cosmic-ray interaction with nitrogen atoms in the atmosphere and is easily detectable in seawater. This rules out a seawater source for the CO2, but supports a mantle origin.

Monster C-isotope excursion dated

September 2007

Geochemists who study the isotopic composition of carbon in limestones aim to build up a picture of its variation as a means of spotting major events that have affected life. Since autotrophic metabolism selectively takes up 12C, the carbon left in seawater is enriched in 13C, and that signature makes it way into sedimentary carbonate rocks. The d13C value of marine carbonates is therefore a proxy for life’s ups and downs. Shortly after evidence for the Earth’s first major glacial epoch, at about 2400 Ma, carbonate d13C lurches upwards by 20‰ (per mil) – greater than at any time before or since, and appears to have remained high for a very long time. Just how long has previously not been known (Melezhik, V.A. et al. 2007. Temporal constraints on the Paleoproterozoic Lomagundi-Jatuli carbon isotopic event. Geology, v, 35, p. 655-658). The Norwegian-Finnish-US-UK-Swedish team dated detrital zircons from sedimentary rocks in Finland that record the carbon-isotope excursion, to give a 2.06 Ga maximum age for the event. They also deduce from other considerations (e.g. intrusion of carbonates carrying the signature by a dated basalt sill) that the build-up of 13C in seawater lasted for about 140 Ma. The new age range is associated with what is believed to be break-up of Palaeoproterozoic supercontinents and the first signs of free oxygen in the environment. Stromatolite-bearing carbonates burgeoned on the continental shelves expanded by drift, the organisms responsible thereby drawing-down 12C. The end of the event when d13C plummeted may mark collapse of these ecosystems and the biomass as a whole.

More on earliest signs of Earthly life thwarts Mars fans

September 2007

In the March 2005 issue of EPN (No graphite in Akilia apatites, no sign of life?) I reported what seemed to be concrete evidence that previous claims for isotopically light carbon said to have been found in 3.8 Ga apatite grains were mistaken: no carbon whatever turned up in the West Greenland apatites after a painstaking survey of the supposed host rocks for the earliest life. That sturdy-seeming refutation has itself been refuted (McKeegan, K.D. et al. 2007. Raman and ion microscopic imagery of graphite inclusions in apatite from older than 3830 Ma Akilia supracrustal rocks, west Greenland. Geology, v, 35, p. 591-594). Not only has the UCLA team found graphite in the Akilia apatites, but also they have confirmed that it is depleted in 13C. The most likely means of selective fractionation of 12C is widely agreed to be autotrophy; i.e. by some form of life.

Aficionados of an origin of life in the Solar System beyond the Earth, particularly on Mars, leapt on the earlier refutation of graphite inclusions in the Akilia apatites. Evidence for the earliest terrestrial life as late as possible in geological time suits their case, which calls for living Martian organisms to be flung Earthwards after meteorite impacts, thereafter to get a grip on an otherwise lifeless but watery planet. That is a puzzling view, if the vast sums of finance for Mars-related research are ignored.

Trilobite evolution more rapid among the most variable species

September 2007

Among other factors, evolution ought to depend on variability among the individuals of a species. That is because the more diverse are forms and functions, and their underlying genetics, the better they can be tested against one another, those of other species and the environment. Fine, yet the hypothesis requires analysis of a great many individual fossils of several species at times when evolutionary divergence seems to have waxed and waned. Having long excited fossil collectors, almost as much as do dinosaurs, trilobites are a worthy source of data. There are close to twenty thousand species known from the Palaeozoic Era, whose end saw their final disappearance. Mark Webster of the University of Chicago, USA waded through the morphological characters of almost a thousand species that are well-represented numerically (Webster, M. 2007. A Cambrian peak in morphological variation within trilobite species. Science, v. 317, p. 499-502), and found that Cambrian species were, on the whole, more variable than were those from later Periods. That matches well with the hypothesis, because trilobite diversification was at its peak during the Cambrian. But was the link determined by more ‘malleable’ arthropod genomes immediately after the Cambrian Explosion than in the later Palaeozoic Era, or by environmental factors? Palaeontologists can only guess at the first possibility. A Precambrian supercontinent had begun to break up into drifting fragments, increasing the number of viable habitats and creating a ‘diaspora’ of increasingly disconnected faunas. There were also fewer families of all organisms that were capable of being fossilized, and which were in competition for potential ecological niches.

See also: Hunt, G. 2007. Variation and early evolution. Science, v. 317, p. 459-460.

And now, the sea anemone genome...

September 2007

Most of the animals with which palaeontologists are familiar are bilaterians: chordates; arthropods; molluscs; brachiopods; various worms etc. At some time in the Neoproterozoic they a common ancestor, according to molecular studies of living representatives. The others animals, such as cnidarians that include corals, are somewhat older in their origins. So the next step in the quest for the origin of metazoan animals had to be sequencing a cnidarian, and the target has been a sea anemone (Nematostella). As expected, it is different from the rest of the bilaterians (Putnam, N.H. and 18 others 2007. Sea anemone genome reveals ancestral eumetazoan gene repertoire and genomic organization. Science, v. 317, p. 86-94), but surprisingly not by much from ourselves and other vertebrates that share a similar degree of complexity with the sea anemone. The implication is that some bilaterian gene sequences became more streamlined and simplified over time, after stemming from a more complex ancestor, whereas that carried by vertebrates shares almost half the anemone’s protein-coding genes. Even more surprising, of the 280 odd human genes implicated in a wide range of diseases 226 occur in Nematostella.

See also: Pennisi, E. 2007. Sea anemone provides a new view of animal evolution. Science, v. 317, p. 27.

The return of the Malthusians

July 2007

The lugubrious predictions of the Reverend Thomas Malthus in An Essay on the Principle of Population (1798) have yet to be confirmed in the field of food supply. In 1972 the somewhat shadowy Club of Rome commissioned a Malthusian examination of physical resources. That appeared in 1972 as Limits to Growth authored by Donella and Dennis Meadows, Jørgen Randers, and William Behrens III. It too offered a gloomy view of the future from an analysis of interactions between the Earth's and human systems using the World 3 systems model.

Limits to Growth may well have united branches of science around the idea of the Earth system, but it has continued to draw scorn from geoscientists for its failure to understand the commercial extraction of metals. By now we would be living in a society bereft on most of them, had Meadows et al. been anywhere near the truth. Oddly, 35 years later—about the maximum time used for forward planning by mining companies—Malthus’s inheritors are back (Cohen, D. 2007. Earth audit. New Scientist, v. 194, 26 May 2007, p. 34-41.). Today’s technology depends on a wider range of metals than that of the early 1970’s: tantalum for cell phones; indium in flat-screen TVs; platinum in fuel cells, and gallium plus indium in the next generation of photovoltaic solar cells. Comparing reserves of metals with extraction rates inevitably gives a finite lifetime of those reserves. Once again, many of them are a lot less than 30 years. So, despite a useful summary of the current situation, lessons of economic statistics remain to be learned.

The most interesting statistics concern where some of these metals are most concentrated. Kazakhstan and South Africa control 95% of world chromium; South Africa has 88% of the platinum; more or less all tantalum is in Australia and Brazil, and if you need antimony China is the port of call for 60% of it. Uniquely, gallium is ubiquitous. Geographic limits to supply creates the conditions for cartels and price manipulation. Tantalum, in the form of its ore coltan, is one of the most portable and profitable metals. Along with diamonds and gold, much of the blood money responsible for more than 3 million deaths in Congo is associated with coltan smuggling. North America, Japan and Europe are short of nearly all metals. What is certain is that they will continue to consume the most per head, and other people are highly unlikely to get the technologies based on odd metals like hafnium  and terbium.

Deep-sea mining

July 2007

One of the counter arguments to Limits to Growth in the 1970s was that its analysis was based on well-known kinds of mineral deposit: there might be many other kinds. At the time, manganese nodules on the ocean floors seemed to offer a great deal, and since they form continually they might be renewable resources. In fact manganese nodules are far from being an economic proposition 30 years on, but other submarine metal deposits are about to come on stream. Among the largest terrestrial sources of copper, zinc, lead, silver and gold are volcanogenic massive sulfide (VMS) deposits, and all formed in volcanically active areas on the ocean floor. Many are forming today, or still lie beneath the sea in now dormant areas of hydrothermal venting.

Old ‘black smokers’ off New Guinea are scheduled to be dredged up commercially from 2009 (Schrope, M. Digging deep, Nature, v. 447, p. 246-247). Nautilus Minerals, the operator, will mine about 200 x 200 m to 15 m below the surface per year, about 40 time less than the volume that would have to be mined on land for an equivalent mass of metals. That is the biggest attraction of young massive sulfides; they are a superficial debris layer rather than being wedged between older and younger sediments in ancient on-shore deposits, that often dip steeply. Environmentalist adherents to Limits to Growth countered the submarine resource solution by fears of massive pollution and marine degradation. The fact is, base metals are pumped onto the sea floor at high concentrations by natural hydrothermal processes.

Review of energy issues

March 2007

Although mainly concerned with renewable options, the Special Section on sustainability and energy in the 9 February 2007 issue of Science (v. 315, p. 781-813) contains a wealth of interesting and informed reading. There is nothing substantial on geothermal energy, but the Special Section does address carbon sequestration from a geoscientific standpoint (Schrag, D.P. 2007. Preparing to capture carbon. Science, v. 315, p.812-813). One side to the approach is deliberately burying the CO₂. The other is to stimulate natural biological productivity in some way and either preserve vast new forests or hope that dead marine phytoplankton are buried in sea-floor mud before being digested. As well as applying to the dominant and probably growing contributor of CO₂, coal, artificial burial can be used with fuels derived from biomass, to give a negative balance to emissions. But such sequestration realistically applies only to point sources, i.e. to power stations, and they have to be sited close to rocks and structures with the potential to retain gas over lengthy periods. The most obvious storage targets would be in the form of petroleum traps. Known oil and gas fields are under serious consideration, especially since gas injection (a well-rehearsed technology) would help maintain their commercial viability. Sub-sea burial has some advantages, as high pressure combined with low temperatures can exploit the ease with which CO₂ changes phase to a liquid, or enters ices as a gas hydrate, much like methane.

However, geological solutions have tight limits. With over a trillion tonnes of CO₂ seeming destined for release before the end of the 21^st century, known petroleum reservoirs globally cannot possible take up the volume. As low place-value resources, their very remoteness from power stations also makes many of them non-starters—Arabia, Iraq, Alaska, Libya, the Niger Delta to name but a few. For the UK, it may be that the almost completely unsuccessful onshore rounds of petroleum exploration here in the 1980s and early 90s may yet pay a dividend, for many suitable structural and stratigraphic traps were found with reserves that would not repay drilling. Disposal of their present fluid contents, whether hydrocarbons or saline brines, would still have be taken into account, if filled with power station emissions. The Bush regime in the US hypes ‘clean coal', presumably with sequestration, as its way forward, ignorant of these and other difficulties.

There is an alternative kind of reservoir to petroleum traps, on a suitably grander scale: continental flood basalts (Jayarama, K.S. 2007. India 's carbon dioxide trap. Nature, v. 445, p. 350). Experiments suggest that CO₂ reacts quickly with the dominant minerals in basalts, under the right conditions—supercritical temperatures and pressures. Although basalts are ‘tight' to fluid transport, many CFBs overlie thick sedimentary sequences, so the gas could be pumped in underneath to react with the basal flows. Coincidentally, India , the world's second largest coal user in future, has the massive Deccan Traps as well as plenty of coal. Estimates of a trapping potential for 15 years worth of global emissions have been made. There are many issues to resolve, such as the bulk permeability of the 65 Ma lavas and whether they will indeed be able to react with hot carbon dioxide. The Deccan is also notable for its considerable relief, dominance by agriculture and distance from coal supplies, all of which pose major challenges. Other vast tracts of CFBs in Ethiopia, southern Africa, Siberia and South America are pretty remote from population centres too, by virtue of their high elevation and lack of valuable resources. The city of Belfast in the UK, however, is close to the Antrim basalts made famous by the Giants' Causeway…

Gold rush

November 2006

As they say, `Gold is where you find it'—gold mineralisation has a great diversity of settings. One of the oddest gold mines is the Ladolam deposit on the island of Lihir off Papua New Guinea— also one of the largest, with gold reserves of around 1300 tons (~41 million troy ounces). Gold is being extracted from an open pit, cooled by water injection, in the crater of a geothermally active volcano at Ladolam. Aside from that extraordinary feature it is one of many different kinds of hydrothermal deposit in which metals are transported and deposited by a plumbing system that delivers hot watery fluids. The hydrothermal system on Lihir is obviously still active, so it is possible to sample the fluid itself by drilling to depths up to a kilometre. Deep sampling is needed to obtain pristine fluids, uncontaminated by mixing with groundwater. Their chemical composition is surprising (Simmons, S.F. & Brown, K.L. 2006. Gold in magmatic hydrothermal solutions and the rapid formation of a giant ore deposit. Science, v. 314, p. 288-291).

The ground in which the deposit occurs is a breccia produced by explosive decompression when the volcano collapsed in its last magmatic throes, at about 400 ka. It is this brecciation that provided the intricate pathways in which gold was able to precipitate from the hydrothermal fluids. The samples have deuterium and oxygen isotopes that show that the fluids are derived directly from magma. They are extremely saline with very high chloride and sulfate ion concentrations. Around 50 kg of the fluid reaches the surface every second. Because it contains about 15 parts per billion of gold, it is possible to estimate how long it might have taken to produce the gold ore body: a surprisingly short 55 thousand years at a current rate of 24 kg of gold per year. Even more surprising is that the Lihir hydrothermal fluid is not particularly rich in gold compared with the fluids emerging from some active volcanoes. For instance Mount Etna is estimated to be delivering up to a tonne of gold every year. However, before rushing off to stake your claims on extinct volcanoes in their last hydrothermal phase, it is worth bearing in mind that forming a super-rich giant gold deposit requires that both gold transport and deposition are closely synchronised in a small volume of rock, otherwise the gold merely ends up so diluted that its extraction is not economic.

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The gold bugs defence

October 2006

Australia is rightly famous for its gold nuggets and some, such as the `Golden Eagle' found at Coolgardie, were as big as a gap-year's rucksack. The curious thing about them is that they are generally found in the most featureless parts of the continent, Western Australia being a case in point. What sharpens the paradox is that these flat areas have been peneplains for up to a billion years. A nugget found in a Yukon or Californian stream is easily attributed to high-energy transport in water, and indeed most of those show signs of long transport in water: they are rounded and pitted. The one kilogram and weightier nuggets from Australia could never have been physically moved across the featureless plains, and most of them come from the alluvium deposited by sluggish Cenozoic drainages, now as dry as a bone—the `deep leads' famous for their gold rushes in the past. They are also oddly shaped, the `Golden Eagle' having wing-like flanges, which any physical transport would bend into conformity, for gold is of course very malleable. One long-held hypothesis is that they formed by precipitation from the extremely noxious groundwater that still persists tens of metres beneath the surface, gold being water-transportable in the form of complex ions such as those involving Au and Cl. But it now seems that the mediator is bacterial in origin (Reith, F. et al. 2006. Biomineralization of gold: biofilms on bacterioform gold. Science, v. 313, p. 233-236).

Frank Reith and his Australian colleagues collected soils that contain small gold grains from goldfields across the continent. A great many have strangely knobbly surfaces and branching structure when scanned under an electron microscope, whereas fine gold grains from primary deposits in hard rock often shows signs of gold's crystal symmetry, or at least highly angular surfaces. The soil-gold particles do look as though they formed in association with living processes. Using stains that fluoresce when bonded to organic matter the researchers found numerous associations between gold and organisms of some kind. When organic material was leached from separated gold grains it revealed DNA closely similar to a bacterium that is known experimentally to precipitate gold from dissolved Au-Cl complexes. Ordinary soil grains showed no such genetic tracers. It looks as if Reith et al. have discovered living biofilms coating the gold grains that the constituent bacteria are in the process of growing. Amazingly, they also found gold-plated living bacterial cells. The probable explanation is that the bacteria live in water so rich in gold (by no means a great deal of it, however) that they are defending themselves from gold's known toxicity—Ralstonia metallidurans, as its Latin name suggests, is a highly metal-tolerant organism. Nuggets may well form as a result of bacterial defence mechanisms.

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How the Amazon formed

June 2006

The world's largest drainage system in the Amazon basin is so huge that it might seem to be an eternal feature of South America, at least since that continent formed when opening of the South Atlantic wrenched it from Africa in the Triassic. The upper Amazon takes much of its flow from rainfall in the eastern slopes of the Andes, but that range is still in the process of formation by tectonic and volcanic forces. A review of the Amazon's evolution in a recent issue of Scientific American (Hoorn, C. 2006. The birth of the mighty Amazon. Scientific American, v. 294 May 2006, p. 40-47) shows that the river system is much younger than you might have expected. Lots of evidence points to the major eastward flow only beginning in the late Miocene, after 15 Ma ago. Before that drainage was northwards into the Caribbean, the reason being that the north-eastern Andes of Columbia and western Venezuela had not formed. When they did begin to rise, they hindered flow to create a huge wetland in what is now eastern Columbia. Eventually a northward drainage route was definitively blocked, so that flow took the easiest remaining route to the ocean; eastwards, to create the Amazon basin.

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Exploration for water on the Moon

May 2006

There is a grim determination at NASA, and in the current US presidential administration that funds it, to get back to and stay on the Moon. Of course, it would be absurdly costly to ship out all the necessities for survival beyond a few days, the weightiest item being water. Protected by the frigid permanent shadows inside craters near the lunar poles, there may be some very old ice there (see Puffing up the Moon in April 2006 issue of EPN). NASA intends to crash a two-tonne spent rocket stage from a planned pre-landing mission into Shackleton crater, hoping to detect water vapour in the debris plume thrown up by the impact. Once the surveying satellite carried by the mission has done its job, that too is going to be crashed in the hunt for what is clearly more precious than gold for would be lunar colonisers.

Source: News in Brief. Nature, v. 440, p. 858.

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Deep-sea mining to realise its promise?

January 2006

On paper, metal resources lying on the deep ocean floor look like an economic panacea. Large areas are covered with either a crust or scattered, potato-sized nodules rich in manganese, copper, cobalt, nickel and several other metals. In some ocean basins, one scoop might provide ore grades for all of them, as in the best onshore multi-metal deposits. `Black smokers' and the metal-rich pillars and muds that develop from them seem just as promising for lead, zinc, copper and even gold: such submarine hydrothermal exhalations probably formed many of the rich massive sulphide deposits sought on land. The 1960s and early 70s seemed likely to foster a fundamental shift in metal extraction, but despite rises in metal prices after the 1973 Yom Kippur war and Iranian revolution of 1978, the excitement faded to insignificance. There were a few ironies too. A ship was designed and almost completed by one of Howard Hughes' many companies, Global Marine, supposedly to harvest ocean-floor manganese nodules. In fact, the venture was to be secretly directed at salvaging a sunken Soviet nuclear submarine, and the code books that it carried, from the floor of the Pacific Ocean. It now seems that ocean-floor mining might be resurrected – assuming that all does not descend into further wrangling over the Law of the Sea and who should benefit from profits (Thwaites, T. 2005. Treasure Ocean. New Scientist, 17 December 2005, p. 40-53). An Australian company called Seacore is soon to drill around New Guinea and New Zealand to evaluate the potential of exhalative deposits. They claim that if thicknesses greater than 15 m, at decent grades for gold, copper, zinc, silver and lead, are found dredging up the ores would be commercially possible. Essentially it would be literally a smash and grab job, unlike the massive logistics of on-shore open-pit and subsurface mining, albeit tempered by problems connected with depths of several kilometres. Understandably, there are environmental concerns about exposing highly anomalous concentrations of metals and associated sulfide minerals, probably in a fine-grained soft state. Ocean ecosystems are fundamentally based on clear water, and mud plumes could wreak havoc far afield. The deposits would have to be sucked to the surface using the air-lift dredge technique pioneered by marine archaeologists, but on a much larger scale. Yet this appears to be more than a means of attracting and siphoning off venture capital, for the groundwork of identifying targets has already been done by Placer Dome, a well-heeled Canadian mining company. Also, the thorny issue of the legality of harvesting the global oceanic `commons' in international waters is being avoided by drilling within national offshore limits, as has long happened with offshore oil development.

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BIFs and bacteria

December 2005

Banded iron formations (BIFs) are by far the largest repositories of economic iron ore on Earth, and mines in them dwarf all but the largest surface coal mines. They also present one of the most enduring paradoxes in geochemistry. BIFs consist of oxidised iron in the form of iron(III) oxide (mainly hematite, Fe2O3), yet formed before about 2 billion years ago, when the Earth's atmosphere and oceans were devoid of free oxygen. In fact the very formation of BIFs presupposes that iron must have been freely available in seawater as dissolved ions of its reduced form, iron(II). Their formation has been linked to the excretion of oxygen by photosynthesising cyanobacteria in the photoc zone of Archaean and Palaeoproterozoic seas, which would immediately combine with iron(II), thereby buffering environmental oxygen at very low levels. The problem with that hypothesis is BIFs show every sign of having accumulated in extremely quiet conditions: they contain the most exquisitely fine banding that in some cases has been linked to a diurnal cycle. The photic zone would have been one of high wave energy. A more environmentally viable hypothesis has to take account of that and place the environment of BIF deposition in deeper water. Biogeochemists of the California Institute of Technology and the University of Alberta have perhaps helped to resolve all the paradoxes surrounding BIFs (Kappler, A. et al. 2005. Deposition of banded iron formations by anoxygenic phototrophic Fe(II)-oxidizing bacteria. Geology, v. 33, p. 865-868). The bacteria that they cite as agents for iron(III) precipitation use the photon energy of ultraviolet radiation to oxidise iron(II) to iron(III), and in doing so use the freed electrons to reduce CO2 and water to carbohydrate – this is not photosynthesis that uses light energy to increase the energy of electrons so that they perform the life-giving reduction. Solar ultraviolet radiation penetrates to much greater depths than the red light exploited by photosynthesisers, and could therefore fuel BIF formation below storm wave base at depths greater than 200m.

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Irish mineralising fluids

November 2005

One of the most revealing field trips that I ever made was to the now-closed Pine Point lead-zinc deposit in Canada's Northwest Territories. Being in the company of the late Doug Shearman (dcd. 2003) of Imperial College London helped a great deal, but the evidence exposed in and around the mine reawoke my interest in sedimentary processes that lead to economic mineralisation. To cut a long story short, Pine Point developed by the passage of Devonian seawater from a vast evaporating basin through a barrier-reef complex, in which a variety of chemical and biological environments, and products of karst formation encouraged the fluid to deposit the metals that it contained on an awesome scale. Limestone-hosted Pb-Zn ores occur widely in Britain and Ireland in rocks of Carboniferous age, the most familiar to me in the English Pennines being in narrow veins. The biggest in Ireland, and they are world-class, are more pervasive of the carbonate host. How they formed has been conjectural and based on geological relationships in what is a small area by comparison with the vast Late Palaeozoic sedimentary systems of the Canadian Shield. Crucial large-scale evidence is meagre. Studying the chemistry of the ore-bearing solution trapped in Irish fluid inclusions reveals a familiar picture (Wilkinson, J.J. et al. 2005. Intracratonic crustal seawater circulation and the genesis of subseafloor zinc-lead mineralization in the Irish orefield. Geology, v. 33, p. 805-808).

Multi-element geochemistry plus strontium and sulfur isotope composition of the included fluids in Irish deposits reveals the signature of considerable concentration of the brines by evaporation, together with their having scavenged metals from crustal rocks as they circulated at depth. Returning to the surface along fault-controlled conduits, the metal-rich brine seems to have mixed with another. As at Pine Point, the sulfur needed to precipitate metal ions as insoluble sulfide ore minerals was probably supplied as hydrogen sulfide excreted by anaerobic bacteria that reduce sulfate ions in seawater. Doug demonstrated this phenomenon in 1981 with a linen handkerchief soaked in lead acetate solution, which he dipped into a foetid swamp seething with such `bugs' on the Pine Point muskeg. `Instant orebody', he cried, as the hanky turned black from fine galena particles.

Although the Irish Zn-Pb ores are more related to faults than to limestone reefs, nonetheless local geology demonstrates considerable relief on the floor of the shallow Carboniferous sea. Fully understanding the `plumbing' and the geochemistry requires, as Wilkinson and colleagues suggest, a regional view of Carboniferous tectonics just before Africa collided with Laurussia. Just before that amalgamation, restricted, evaporation-prone basins would have formed. On a continental scale the circulation of their concentrated brines would have followed active faults systems that reached the shallow sea bed: a great deal more complicated than what is plain to see at Pine Point, given the eye of one of post-WW2 Britain's lions of geology.

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Oxygen and mammalian evolution

So much in the geological history of surface processes depends on either the dearth or the superabundance of oxygen. That is no surprise for a host of reasons, one being that it is the most reactive common element when free of bonds, and another is that the most powerful means of releasing oxygen is the capture of energetic solar photons by the pigments residing at the heart of photosynthesis. To grossly paraphrase James Lovelock, the principal reason for not sending people to Mars to search for life is that the planet's atmosphere tells us that even if was there, it wouldn't be very exciting. Oxygen gas is at vanishing low levels on the Red Planet, even if there is lots locked up in its iron-oxide rich surface.

The greatest event in the history of terrestrial life, apart from its emergence, was exploitation of the means of breaking hydrogen-oxygen bonding in water, which is what common photosynthesis is all about. It opened the entire planet to life from the restricted, though diverse habitats of most Bacteria and Archaea in the earlier anoxic world. First, oxygen-excreting cyanobacteria were able to colonise the entire ocean surface, depending on available nutrients. In doing so and generating free oxygen they threatened every other organism that used metabolisms based on other kinds of chemistry: oxygen is highly toxic because of it propensity to grab free electrons. Balanced by its oxidation of iron in early oceans, severe oxygen stress did not emerge until halfway through Earth's history. Once it did become able to accumulate in air and water, all ecosystems faced havoc. Dominant prokaryotes slunk to rare places of refuge, while others seem to have combined symbiotically in resisting oxidation. Their creation of the Eucarya that depend completely on available oxygen led, through the emergence of algae and then plants, to an accelerated stoking up of oxygen generation.

Once vegetation began to cloak the land, an extra 30% of the planet's surface opened new vistas for animals and increased oxygen production and complementary burial of carbon. Indeed, explosive growth of atmospheric oxygen during the Carboniferous resulted in animal expansion to the air, through ominously huge insects. The first clearly traced ancestors of mammals seem to have appeared in the Permian, though their descendants only got the chance to dominate once reptiles, especially dinosaurians, lost their grip as a result of the K-T extinction. At the time of a far greater loss of living diversity, at the end of the Permian, it is now clear that in a relatively short time oxygen levels had fallen from their highest to one of the lowest in the Phanerozoic record (see New twist for end-Permian extinctions in the May 2005 issue of EPN).

Anoxic oceans were a regular feature of the Mesozoic and early Cenozoic. It is their preservation of abundant buried carbon that holds a key to, in an anthropocentric sense, the greatest of evolutionary leaps; the rise of large mammals and ourselves. A large team of US scientists has used the now abundant records of carbon isotopes in both buried organic matter and marine carbonates to reconstruct changes in atmospheric oxygen content (Falkowski, P.G. and 8 others 2005. The rise of oxygen over the past 205 million years and the evolution of large placental mammals. Science, v. 309, p. 2202-2204). Their modelling suggests that at the start of the Jurassic, atmospheric oxygen stood at around only 10%. Through that period it rose dramatically to 16%, fell equally abruptly, thereby creating the conditions for some of the largest sources of petroleum, and then rose again to about 18%. Cretaceous times saw a slow rise, until around the Palaeocene-Eocene boundary (55 Ma). The middle of the Cenozoic was a further period of dramatic increase in oxygen levels, to their highest (~23% in the Oligocene) since the peak during the Carboniferous. Latterly atmospheric oxygen has waned to around 21% today.

Falkowski et al. compare their new atmospheric oxygen curve with evolutionary spurts among mammals, of which the simplest to understand is the parallel rise in mammalian average size. The metabolism of all mammals, like that of birds, has 3 to 6 times the oxygen demand of reptilian bodily functions. Not only were Mesozoic mammals challenged in stature by the air they breathed, but reptiles were easily able to grow to monstrous proportions because of their less demanding physiological processes. The first signs of the placental nurturing of mammalian foetuses, which requires a high oxygen level, coincides roughly with the Mesozoic maximum (100-65 Ma). The end-Cretaceous extinction of the dominant dinosaurian reptiles removed the main competition against the subtle advantages of placental mammals, and was followed by further increase in oxygen. The Cenozoic permitted terrestrial mammals to reach sizes almost comparable with dinosaurs, and to go beyond them among whales. Moreover, it saw explosive diversification, one branch of which, the primates, led to ourselves.

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Did oil and gas fields form during the Precambrian?

August 2005

Since the origin of life it is certain that a proportion of biological materials would have been preserved in sediments after organisms died. As today, such material would have evolved or matured as the host sediments were buried and heated. There is plenty of evidence that such maturation did occur as far back as 3250 Ma ago, but signs that oil-fields formed by migration and trapping have proved elusive. Several lines of evidence, such as carbon-isotope anomalies in Precambrian limestones, point to periods when enormous amounts of organic material were buried, much as happens in the formation of Phanerozoic petroleum source rocks during periods of ocean anoxia. Before about 2400 Ma, when evidence for an oxidising surface environment first appears in the rock record, such conditions would have been pervasive. The first hints of large-scale petroleum formation and migration have been found in the low-grade Pilbara craton (3500-2850 Ma) of Western Australia and 2770-2450 Ma sediments that overlie the older Archaean complex (Rasmussen, B. 2005. Evidence for pervasive petroleum generation and migration in 3.2 and 2.63 Ga shales. Geology, v. 33, p. 497-500). Black shales in the Pilbara contain not only lots of fine-grained carbonaceous matter, but some in forms that clearly suggest that they had been thermally matured (`cracked') to low-viscosity fluids that could migrate. There are blobs of bitumen contained within iron sulfide layers that seem to have formed later, to engulf petroleum liquids. Molecules within the bitumens resemble those formed by photosynthesising blue-green bacteria, methanogen and sulfate-reducing bacteria and arguably perhaps primitive eukaryotes. It appears that the bitumens probably formed as residues as lighter and more fluid hydrocarbons migrated out of these substantial source rocks. What has yet to be demonstrated are Archaean and Palaeoproterozoic reservoir rocks where such migrating petroleum accumulated. Another question is whether or not the source rocks, which are extremely widespread and thick, might have retained some potential for sourcing petroleum much later in the geological history of Western Australia and similar cratons elsewhere.

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Two sides to reducing carbon emissions

May 2005

Scientists in developed countries are more or less unanimous that climate is warming because of rising CO₂ levels from the burning of fossil fuels. That spurs calls for less reliance on fossil fuels and more use of renewable energy resources, including biomass. The situation for the other two-thirds of humanity is much different. The majority depends on biomass fuels (wood products, agricultural waste or animal dung). Unprotected burning of biofuels releases such levels of carcinogens that 1.6 million people including 400 thousand in sub-Saharan Africa, mainly women and infants, meet an early death each year. By 2030 this may rise to over 9 million, if current fuel use continues. Biofuels also devastate woodland cover, and burning animal dung reduces natural fertiliser used on fields: two contributors to the inexorable decline in conditions of life in the "Two-Thirds World". Energy researchers at Harvard and the University of California have examined the options for household fuels in the light of these "counter-environmentalism" facts (Bailis, R. et al. 2005. Mortality and greenhouse impacts of biomass and petroleum energy futures in Africa. Science, v. 308, p. 98-103). A safer alternative to wood and dung burning is the use of charcoal, yet that would increase CO2 emissions by around 50%, as well as increasing loss of woodland. The higher energy content of non-coal fossil fuels would actually decrease the "greenhouse" burden, while improving health dramatically. They estimate that a shift to petroleum-based household fuels would delay between 1.3 to 3.7 million deaths per annum, by 2030.

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Drilling into the San Andreas Fault?

February 2005

It seems that in order to really get a feel for the physical and chemical processes involved in faulting, drilling into an active one is a good idea, or at least that seems to be the driving motive behind the SAFOD (San Andreas Fault Observatory at Depth) project of the US Geological Survey (Cohen, P. 2005. Journey to the centre of a quake. New Scientist, 5th February 2005 issue, p. 42-45). It might make sense, because pressures of pore fluids near active faults seem likely to exert some influence over whether a fault segment moves or not. Overpressured fluids can serve to lubricate the otherwise sticky fault surface. In the case of the San Andreas, activity is fragmented. Detailed monitoring of microseismicity near Parkfield, California revealed that a mere 100 x 100 metre patch on the fault plane was responsible for much of the activity. It lies about 3 km down, just within reach of oil-drilling technology. In fact the Parkfield segment is one of the shallowest active zones on the whole fault.. There are already holes in place, drilled to 2 km to host monitoring instruments, and new drilling methods eventually will allow sideways puncturing of the fault plane so as to install more. But even sophisticated drilling is still largely a blind operation, which inevitably hits snags, and there have been several in the SAFOD project. One severed communications with existing instruments. The general idea behind SAFOD is that fault displacements propagate from small "nucleation" sites. The length of the fault that undergoes displacement during one movement is generally correlated with the magnitude of the resulting earthquake. Parkfield seems to be such a nucleation site, but since the earthquakes associated with it are of small magnitude chances are that interfering with it will not accidentally release a large one. The benefits, set against the risks and undoubtedly high costs, are mainly that even the tiniest motions can be monitored. Surface monitoring of course cannot investigate pore fluids and other phenomena, and nor can it detect events less than magnitude 0.5, whose energy is absorbed by rock before it can reach the surface. By monitoring what happens in events with a range of small magnitudes, it ought to be possible to develop earthquake theory to the point where at least the role of fluid pressures, the feedback between earth vibrations set off by one event and movements on a later one, and the effects of mineralogy on friction that resists movement can be assessed. Whatever, once in place, the wait for useful results to accumulate could be a long one, so SAFOD is planned for a 15 year lifetime More information on SAFOD is available at http://www.earthscope.org/safod/index.shtml

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Prize for solving the world arsenic crisis

February 2005

Almost every month there are announcements of yet more areas of the world that face hazards from natural contamination of groundwater by release of arsenic from whichever minerals host it in sediments. In Bangladesh alone, the WHO estimates that tens of million people are at risk. Although large tracts of the US and other rich countries do have arsenic levels in groundwater that are above the maximum recommended for safety, the crisis is one that most severely affects some of the world's poorest and most populous countries. To help solve this massive public health problem, the National Academy of Engineering is offering the Grainger Challenge Prize for Sustainability, a sum of US$1 million, to the individual or individuals who design and create a workable and cheap water treatment system that anyone can use for arsenic-contaminated groundwater in Bangladesh, India, Nepal, and other developing countries. The most likely cheap remedy lies in the use of iron hydroxide as a means of absorbing dissolved arsenic, but several other candidates, including coal fly ash and limestone, together with biological precipitation, have recently begun tests.

Incidentally, the action in the UK against the Natural Environmental Research Council, for negligence in failing to analyse for arsenic in Bangladesh groundwater in the early 1990s, on behalf of 400 Bangladeshis affected by arsenic poisoning, received the legal go ahead to appeal against an earlier decision by a British court to throw out their case. My thanks to John McArthur of University College London for this news.

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Grow your own bridge, hill or fortress

November 2004

From time to time, truly odd ideas emerge, even from such a conservative bunch as geoscientists. They are often based on quite mundane science. If you pour sulphuric acid on limestone, of course it fizzes violently because CO 2 is a product of the simple reaction. Less noticeable is that the other product, hydrated calcium sulphate or gypsum, is considerably less dense than the calcite in limestone. The solid residue swells. "What if….?", thought Dutch geochemist Roelof Schuiling (Ravilious, K 2004. The new stone age. New Scientist, 20 November 2004, p.38-41). His idea was to put the simple phenomenon to practical use; infiltrate sulphuric acid into porous limestone and the swelling will bulge up the surface. This does happen naturally, where sulphide-sulphate oxidising bacteria generate sulphuric acid, which renders limestone to an easily erodable mess, and in some soils generates gypsum lenses that bulge up the ground into surface blisters. Schuiling reckons that the huge sulphuric acid surplus, created partly by removing sulphur from vehicle fuels, could be used as a kind of geo-engineering tool on a vast scale. For instance, the coralline shallows beneath the shallow Palk Straits that separate India and Sri Lanka , could be induced to bulge up and create an island ridge, and so complete what is known as Adam's Bridge that nearly links the two countries. Closer to home, the Low Countries might become the "Slightly Higher Countries". Worryingly, the technology to make the process viable is simple, if a little expensive on the scales envisaged. The worry, of course, is yet more CO­ 2 emission plus the effect on the environment of so much sulphate and a massive fall in pH.

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Onshore gas hydrate reserves close to recovery

February 2004

The Mackenzie delta in Arctic Canada has been an area of conventional hydrocarbon exploration for decades. In 1972 methane-ice mixtures in the permanently frozen ground were discovered in one well at a depth of about a kilometre during exploratory drilling. They are rich, with up to 90% of the pore spaces in alluvial gravels being full of the white gas hydrate. Being associated with conventional gas at greater depths, there is a good chance that combined production could make the considerable reserves economic. On their own, gas hydrates are not yet economic, even onshore, since they would need heating to break down the peculiar compound, and natural gas prices are currently at a low level. Economics also depend on a conventional gas pipeline being extended to the area Tests and computer simulations suggest that production of deeper conventional gas can lower the pressure on the gas hydrate inducing it to break down and add to the flow from a well. In maybe 10 to 20 years production could begin. The likely origin of the Canadian reserves and those in the North Slope of Alaska is from methane leaking from deeper reserves to "freeze" in the colder conditions at shallow depths.

Arctic North America could eventually produce up to one sixth of current US natural gas consumption from onshore gas hydrate. Of course, vastly greater gas-hydrate potential exists offshore—between 10 000 to 42 000 trillion cubic metres (tcm) world-wide, compared with 370 tcm of estimated conventional gas reserves. Methane (CH₄) burns to produce less carbon dioxide per unit of heat energy than more carbonic natural gas, so is a means of easing "greenhouse" gas emissions. Potentially it could be feedstock for CO₂-free hydrogen production. Pressures on the economy of Japan, which has very few natural energy resources, have prompted Japanese researchers to begin exploratory offshore drilling into the Nankai trough offshore of SE Japan, where there are potentially rich reserves of gas hydrate in sands. This may produce commercially in 10 to 15 years. The thorniest problem with many gas hydrate deposits is that they are in "tight", fine-grained sediments.

Source: Kerr, R.A. 2004. Gas hydrate resource: smaller but sooner. Science, v. 303February 2004, p. 946-947

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Supergiant hydrocarbon field just leaked away

December 2003

The largest producing hydrocarbon field, which is unlikely to be bettered, is the Gharwar oil field of Saudi Arabia. It extends for about 3500 km² and still contains 80 billion barrels of oil. Anything comparable in size, or bigger, would have been tripped over decades ago, because of the sheer size of the geological trap structures. That is one of the reasons to believe that hydrocarbon resources are unlikely to last until the 22^nd century, unless other kinds of accumulation can be exploited economically. There are vast onshore reserves of tar sands from which the more volatile hydrocarbons have leaked away, but for them to become generally useable requires very large rises in oil price. The same conditions will have to prevail before oil shales, the source rocks for conventional hydrocarbons, become viable.. Had tectonics not induced the Colorado Plateau to rise and be eroded, oil would be far cheaper and more secure, and the USA would have even more economic and political clout than it already has. The recognition of unroofed hydrocarbon fields in that region of western North America may therefore come as a relief to many people (Beitler, B., Chan, M.A. & Parry, W.T. 2003. Bleaching of Jurassic Navajo Sandstone on Colorado Plateau Laramide highs: Evidence of exhumed hydrocarbon supergiants. Geology, v. 31, p. 1041-1044).

The desert dune sandstones of the North American Jurassic form some of the world's most spectacular scenery, because of their vast outcrops in Utah national parks, such as Monument Valley. Their attraction lies in the colours of the sandstones as well their deep incision. Discovery of what was once a series of supergiant hydrocarbon fields lies in variations of that coloration. When laid down, the sandstones were reddened by precipitation of ferric (Fe³⁺) oxides from water that seeped through them during diagenesis under oxidising conditions. However, large tracts now show signs of variable bleaching, which gives the variegation that tourists flock to see. Iron has been removed in places, and for that to happen, the insoluble Fe³⁺ has been reduced to the more soluble Fe²⁺, or ferrous form. That can occur when conditions in the rock change to highly reducing, as in the case of hydrocarbons migrating in along with water. Most wind-blown sands have good porosity and their uniform grain size induces excellent permeability as well, so they are near-ideal reservoirs. However, for them to become permeated by hydrocarbons that migrated from source rocks (usually shales) requires pathways and structures in which the hydrocarbons can be trapped. The Jurassic of the western USA has alternations of these sandstones with less permeable rocks, and was deformed into huge open anticlines during the Laramide orogeny, that originally might have created such traps on a regional scale. Brenda Beitler and her colleagues from the University of Utah have mapped the zones of bleaching using Landsat-7 Enhanced Thematic Mapper data. Sure enough, the most bleached areas coincide with the crests of the large upfolds, and with reverse faults that link them to basins with source rocks and may have acted as fluid migration pathways. The pore volume that could have been available for hydrocarbon trapping would have been 2200 km³, equivalent to 18.5 trillion barrels, about 6 times larger than estimates of the modern world's recoverable oil. Since the Cretaceous, the Colorado Plateau has undergone more than 2 km of uplift and every single upfold has been breached and deeply incised. Sorry George, the oil leaked out long ago! The inevitable leakage of the gas fraction, perhaps as much as 2 billion tonnes, could have warmed the Tertiary climate, if a significant fraction were released quickly. The main incision of the Colorado Plateau was probably in the late Miocene (around 6 Ma), when ocean-floor data suggest global warming of the order of 0.5 to 1ºC.

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Background to globalisation of water resources

December 2003

"The second provision of any civilised society after a system of laws, is that of a safe water supply" is anonymously attributed in the repeated warnings about the parlous state of water provision for about two thirds of the world's population. Many of the private companies that took over the public water authorities in Britain now stride the planet organising that provision. In South Africa, the resulting increases in water pricing are the main source of anger throughout the poorer sections of its population, especially in the townships. In Cochabamba, Bolivia there have been mass protests about similar price hikes that came years ahead of any improvement in supplies. A consortium of national and transnational companies needed the extra cash to finance a major dam project, instead of looking to global investors in the project. Science carried a lengthy article that provides a context for this new trend in globalisation (Gleick, P.H. 2003. Global freshwater resources: soft-path solutions for the 21^st century. Science, v. 302, p. 1524-1528)

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Titanic solution to unpalatable water

August 2003

Currently around a billion people are at severe risk from drinking contaminated water, and whenever there is a major human crisis refugees are placed in the same plight. The main solution would seem to be drilling wells that tap groundwater that aerobic bacterial action cleanses of most pathogens. That is essentially true, but some groundwater is rejected even by people suffering the most extreme privations. It has the appearance of water from the radiator of an aged lorry, because it contains abundant dissolved iron that immediately precipitates as red-orange slime when exposed to the air, tainting food and staining clothes. A solution may arise from studies as far from drought-stricken areas as one could possibly get; concerning the way in which deep-sea wrecks decay away. The discovery of the wreck of the Titanic in 1985 and recovery of parts of it later by marine historian Robert Ballard, revealed that its ironworks were being consumed by bacteria that created stalactite-like masses of iron oxides, known as "rusticles". Detailed microbiological studies found a highly complex harmony of different bacteria that created and inhabited the rusticles. Effectively, they were eating the mighty ship at a rate of about a tonne every ten days by exploiting the energy released by oxidation of iron. It may prove possible to harness the habits of these iron-loving bacteria to remove iron from groundwater and make it palatable

Source: August 2003 Fry, C. 2003. Iron rations. New Scientist, 26 July 2003, p. 36-37.

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Hydrological madness

July 2003

Regular readers of New Scientist know that Fred Pearce is the scourge of dam builders, especially those with near-megalomania about vast barriers and reservoirs. Back in the late 1960s Canadian environmentalists were horrified to learn of plans being developed to divert southwards water that naturally flows along the great rivers of the Canadian Shield to the Arctic Ocean and Hudson's Bay. This was NAWAPA, the North American Water and Power Alliance. NAWAPA is still a live ambition for supplying the water-hungry west and mid-west states of the USA. The former Soviet Union put such grandiose plans into effect, one outcome being the dramatic shrinkage of the inland Aral Sea. Pearce returns to continental water transfer in an important review in the weekly for whom he has worked for many years (Pearce, F. 2003. Replumbing the planet. New Scientist, 7 June 2003, p. 30-34). His trigger is the filling of the giant Three Gorges reservoir on the Yangste, one of whose aims is to channel water northwards to augment supplies to the increasing parched plains of central eastern China. But this is only the start of an awesome venture, that will also shift the equivalent of 25% of the Nile's flow from Tibet's glacial meltwater that feeds the Yangste into the Yellow River, which now barely trickles into the Yellow Sea. India seems bent on snaffling much of the flow from the Ganges and Brahmaputra catchments into the drought-prone south of the subcontinent. As well as the huge disruption of people and environment that schemes such as these must entail, Pearce highlights the vast economic costs. India's continental engineering will eat up the equivalent of 40% of its GNP.

Obviously, such huge ventures throw up equally large political and ethical questions, which are not easy to resolve. In many cases the perceived needs for regional water transfers stem from very wasteful water use, particularly in agriculture. Using drip or trickle irrigation, which needs large-scale application but relatively low-cost and simple technology can reduce water requirements dramatically, simply by reducing losses by evaporation from canals. In semi-arid areas as much as 70 % of channelled water never reaches the crops for which it is intended. Governments such as those of India and China depend so much on rural support that they might commit political suicide by pressing for changes to practices that date back millennia, so they opt for the spectacular, quick fixes. Yet there are other such schemes that might transform the livelihoods of some of the worlds most destitute people in the Sahel and Horn of Africa. One suggestion is to divert part of the largely unused river flow through humid tropical Central Africa across the Sahel to reach Lake Chad. Another, not mentioned by Pearce, is to dig a channel that will flood the Danakil Depression of Ethiopia and Eritrea, which lies about 100 m below sea level. Topographically, this would be relatively easy, because only about 30 km of low-lying coastal plain separates the Red Sea from the Depression. The flow could generate hydropower in a power-starved region, and evaporation from the resulting saline lake would boost rainfall in the world's hottest place, and perhaps allow harvesting of the many salts that would be precipitated, including potash fertilisers. Solar energy could also be used for low-cost desalination. However, no-one can guess at the climatic and ecological consequences of changing humidity in both the Chad and Danakil basins. Yet, water is becoming the most strategically important physical resource so rapidly that the enormous economic implications for transnational contractors, and political prestige associated with regional transfer schemes will drive them ever onwards. There is one glimmer of hope, which Pearce mentions; ordinary people in Rajasthan, India's driest state, have resurrected old practices of water harvesting, and find that they are more secure than those who rely on state-sponsored canal supplies. The root issue is that rainfall disappears either by run-off or evaporation in a matter of days, unless it is stored somehow. Any habitable place has rainfall, albeit irregular in drought-prone areas, and quite low-cost ingenuity can "bank" the transient spates where the water is needed.

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Water resources and bullocks

June 2003

Desalination is often touted as a solution to shortages of clean drinking water, but the most common method, using reverse osmosis, is really a luxury. It relies on electric pumps driving salty water through a membrane, so that salt concentrates on the high-pressure side of the membrane, allowing nearly fresh water through it. This method is widespread among power-rich economies along desert coastlines, but has done nothing to help the less fortunate millions in countries where electricity is unaffordable. Indian scientists, unsurprisingly, have developed a means whereby fresh water might become accessible to most coastal people in the tropics. They have worked out how to gear bullock power to reverse-osmosis pumps, so that a pair can produce up to 3000 litres each day and supply entire villages. If a bullock can do it, then why not donkeys or camels in even more arid coastal areas?

Source: June 2003 Coghlan, A 2003. All hooves to India's pumps. New Scientist, 10 June 2003, p. 19.

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Wars in the Congo and physical resources

April 2003

The Democratic Republic of Congo (DRC, formerly Zaire) is the most war-torn country in Africa, and has been since Belgium relinquished its largest colony in 1960. It is also Africa's most mineral-rich country outside of the Republic of South Africa. Most of its population, particularly outside of the major cities, has been repeatedly caught up in the most savage conflicts, which have left more than 2 million dead and far more displaced or reduced to conditions of bare survival. From the civil war following the attempted secession of the most mineral-rich province of Katanga shortly after independence to the present, Congo peoples' suffering has centred on various groups' attempts to loot its mineral riches. Despite the DRCs strategic importance as a supplier of cobalt and tantalum, for which it is the world's largest source, and its world-ranking production of copper and zinc, diamonds (up to one third of a ton annually, mainly of industrial quality), and gold (up to 6 tons annually), neither the UN nor those powers currently engaged in Iraq have made any determined effort to end the 40-year plight of its people.

Every geologist suspects that war in the Congo has a direct link to its mineral resources, but until recently its economic basis has remained carefully hidden by the various warring groups, and to some extent by the world mineral industry which ultimately benefits. Ingrid Samset of the University of Bergen in Norway has reviewed the particular role of diamonds in the recent phases of conflict, that followed the fall of the reviled President Mobutu in May 1997 (Samset, I. 2002. Conflict of interests or interests in conflict? Diamonds and war in the DRC. Review of African Political Economy, v. 93-94, p. 463-480).

Following the occupation of eastern DRC by armies from Rwanda and Uganda in collusion with the anti-Kabila RCD forces, and the sending of troops by Namibia, Angola and Zimbabwe to assist the Kinshasa régime in mid 1998, official figures for production of and revenues from all physical resources fell far more dramatically than for other exportable commodities, such as coffee. The largest falls involved diamonds and coltan (columbite-tantalite). Both combine very high value relative to weight (coltan trades at up to US$400 per kilogram) with simple extraction technologies. Both are mined extensively by artisanal groups, and so are attractive for quick, clandestine looting. Tantalum is used in making capacitors, specifically for mobile phones, and the boom in the price of coltan followed the vast expansion of cellular phone networks world wide. Zimbabwe, and to a lesser extent Angola and Namibia have won official concessions for diamond mining in exchange for their military involvement. The embattled ZANU-PF régime in Harare is probably highly dependent on revenues from Congo diamonds. In the case of Uganda and Rwanda's involvement with opposition forces in eastern DRC, the economic aspects of their roles are more difficult to dig out. Both countries lack diamond or coltan reserves, yet in the case of diamonds, their exports rose by 12 and 90 times, respectively, since the start of their involvement. Comparing their export values with probable production in the area that they help control, there is a shortfall of about US$13.5 million. Samset suggests that "missing" diamonds are being used directly as easily "laundered" barter goods in exchange for arms. In the case of coltan, Rwanda is estimated to have benefited by US$250 million, at the time of the tantalum price peak in 1999-2000, from looting of eastern DRC. Neither coltan nor diamonds carry signs of their origin (but see Forensic geochemistry to foil "fencing" of conflict diamonds in EPN, June 2002), so tracking looted goods and bringing those involved to account is no easy task. The state of Israel is heavily involved in the gem diamond trade, as is the Republic of South Africa, and the USA accounted for more than 80% of all industrial diamond exports from the former Zaire. One of the oddest coincidences was the sudden involvement in peace-making attempts during the Eritrea-Ethiopia war of 1998-2000 of the government of Rwanda, despite its geographic remoteness from that particular conflict and lack of diplomatic experience.

See also: http://www.american.edu/TED/ice/congo-coltan.htm for an analysis of the role of coltan in the DRC conflict.

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Microgravity and diamonds

October 2002

Prospecting for diamonds relies either on lucky finds in sediments or locating the odd kimberlite pipes that brought diamonds from depths greater than 100 km in the mantle, where they form. Such has been the centuries-old frenzy for diamonds that most deposits of the trip-over kind have been found. One of the last major diamond fields turned up in Arctic Canada, after prospectors panned their way upstream of glaciers that had dropped the odd diamond in Canadian Shield tills. It is simply too costly to keep repeating this painstaking exercise to satisfy the enduring demand for diamonds of all qualities. New sources probably exist in huge, unexplored regions of Canada, Australia, Africa and north Asia, yet kimberlites, often having broken down to clays and forming little by way of topographic features, are not easy to find. Great efforts have been made to harness conventional remote sensing that uses reflected and emitted electromagnetic radiation, but with little success. Aside from the innocuous nature of kimberlites, most prime ground is either flat, vegetated steppe in areas once affected by glacial conditions, the featureless soil covered tracts of interior Australia or tropical rain forest, where remote sensing simply does not work well enough.

Kimberlite pipes have round traces at the surface and the rock has a different density from common rocks of the upper crust, so one means of locating them is by looking for circular patterns on gravity maps. But they are small relative to the resolution of regional gravity maps, which are generally constructed by careful measurement of gravitational field potential at points on the surface. It is not that gravimeters are incapable of detecting differences due to rocks with anomalous density, but that sample spacing is too coarse (>1km) because of the high cost of field surveys. Maps of the Earth's magnetic field and emissions of gamma-rays by radioactive isotopes are routinely created at suitable resolution by aerial surveys, but kimberlites show only subtle features on them. Airborne gravity surveys have been a grail for explorationists for many physical resources, but insufficient economic interest has blunted the search for a way of overcoming the effects of turbulent accelerations during flight, which spoil measurements of the actual gravity force field. Mining company Broken Hill Proprietary – Billiton's venture into diamonds after their acquisition of the Ekati deposit in northern Canada has encouraged them to seek a cunning approach to the problem. Whereas measuring gravitational potential from the air is a tough nut to crack, the US navy had developed an instrument to measure changes in the gradient of the gravitational field that can overcome varying accelerations, to help nuclear submarines navigate without recourse to giveaway sonar "pings". BHP-Billiton is into this technology in a big way, now that it has been declassified. While gravity gradiometry offers one way of revolutionizing the precision of gravity surveys, other methods are possible, and it is rumoured that geophysicists who try to measure even tinier shifts in the gravitational field to monitor the rise and fall of magma in volcanoes are onto a cheaper and less convoluted method...

Source: Nowack, R. 2002. Pulling power. New Scientist, 21 September 2002,p. 42-45.

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Exploration licence lepton by physicists

August 2002

The search for hitherto undiscovered and totally hidden hydrocarbon reserves has attracted a bizarre range of patented techniques over the years. They range from using thermal images of the sea surface to pinpoint stationary cold spots that may mark deep water upwellings driven by rising natural gas bubbles, through helicopter borne hydrocarbon sniffers to fine-resolution aeromagnetic surveys to detect anomalies due to magnetite formed by bacteria that metabolise oil and reduce hematite to magnetite. Most have a rational scientific basis, but there are a few that defy reason. Most explorationists have been button-holed by dowsers, but the latest venture seems to have convinced Her Majesty's Government, to the extent that the Department of Trade and Industry has granted three licences to explore parts of rural England, generally known for their fox-hunting aficionados.

 A company, Technology Investment and Exploration Limited of Guernsey, has invented a device that they call a "microlepton generator", supposedly based on the Nobel-winning work of Martin Perl of Stanford University, who discovered the subatomic tau lepton in the early 1990s (http://physicsweb.org/article/news/6/7/1). They claim that their beam of microleptons, highlights areas underlain by hydrocarbon deposits, when used to illuminate satellite images. They contend that oil generates vast amounts of microleptons that produce subtle effects on such images, but they can only be detected by microlepton beams TIEL intends to deploy a hand-held microlepton detector from an aircraft overflying areas that they claim have given "tell-tale" signatures using their instrument. In this respect, they are one up on particle physicists, who have so-far failed to detect microleptons under laboratory conditions. The smallest known lepton is the electron that is 1000 times more massive than the microleptons claimed by TIEL at the base of their leading-edge technology. Despite that, it is hardly likely to have escaped discovery by the best-financed branch of science.

Robin Marshall, a particle physicist at Manchester University, discovered that microlepton technology is based on a paper published by a Russian physicist called Anatoly Okhatrin in the journal Doklady in 1989. "He was clearly either mad, drunk or deluded," says Marshall. "He spun a cone of lead weighing several kilograms in front of a pin-hole camera and claimed to have photographed a 'glow' surrounding the cone that was due to microleptons." Enough said? No. One of TIELs targets is in Charnwood Forest in Leicestershire, well-known to geologists for not being above an oil-prone basin. Indeed the area is underlain by Neoproterozoic volcanic rocks that bolster the Midland craton of central England, which thwarted extensional basin formation from the Silurian to modern times. Still, an onshore exploration licence is a handy item for a company's CV.

TIEL is not the only outfit making these claims. Another, Alkor International, seems to have a Russian link, and its website (http://www.alkorinternational.com/) gives details of the method it uses; "special" photographic processes, computers and software, and is also claimed to locate water resources and gold deposits!

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Forensic geochemistry to foil "fencing" of conflict diamonds

June 2002

The longest and most devastating wars in history have centred rather more on economic interests than nationalism or chivalrous defence of principles, and in some case a specific commodity created an issue that annexation served to resolve. For instance, the 1914-18 war was not unconnected with the vast iron ore reserves of Alsace-Lorraine. Similarly, the Nigerian civil war of the late 1960s was bound up with the oil reserves of the Niger delta, and that of Congo centred on base-metal resources of the Copper Belt, particularly the fact that vast strategic reserves of cobalt occur in its Congolese sector. The running sores of present conflicts in Africa—Angola, Congo, Sierra Leone, Liberia—are about and financed by gems that adorn the rich, the self-regarding and the lazy. These diamond wars are a direct concern of geologists, for who else finds the elusive kimberlites and traces the natural dispersion of the diamonds that they contain?

More than 30 years on from the start of gem-related carnage in Africa, in which dealers and giant mining corporations have been implicated up to their collective eyebrows, local people have been drawn into "illicit" diamond mining when their livelihoods have been destroyed by perpetual danger and insecurity. Preyed on by many so-called "rebel" groups, even kids as young as 8 or 9 have been armed and set upon one another and the inhabitants of regions blighted by the presence of what is no more than an allotrope of carbon. Eugenie Samuel writes on a possible means of defining the source of diamonds "fenced" by the gem trade from on-going conflict zones (Samuel, E. 2002. Diamond wars. New Scientist, 25 May 2002, p. 6-7). It seems that ultra-thin coatings on rough diamonds carry a geochemical signature from the chemically diverse kimberlites and other unusual mafic rocks that carry them from the mantle. Given research on rough stones from every kimberlite province it should be possible for this forensic approach to help stamp out what is the world's largest blood trade.

The problems are many. For a start, trade in "conflict diamonds" is now illegal, so it is unlikely that rough stones used to calibrate the technique would be given a bona fide provenance by dealers. It would be a courageous geochemist who went sampling in interior Congo, Angola, Liberia or Sierra Leone. The method clearly requires funds, yet the obvious source, diamond mining and trading companies, are engaged in their own tagging schemes that use using ion beams to bar-code their products on a minute scale. In fact this tagging method was developed under great secrecy to distinguish from the "real" thing perfect artificial diamond gems synthesized by Russian geochemists. Finding diamonds requires considerable exploration, which involves systematic sampling of sediments along streams that drain likely kimberlite-bearing ground. Although high-quality rough found by geologists would be sold, there must be small diamonds archived from such sampling by mining companies and geological surveys. They could be supplied to forensic geochemists to calibrate the method. In Sierra Leone, for instance, the diamond fields were located in the early 1950s by geologists of the then Overseas Geological Survey—part of what became the modern British Geological Survey. Belgian and Portuguese equivalents may well have archival material from Congo and Angola.

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Slime to the rescue

December 2000

In waters that are anaerobic, metabolism of dead organic matter requires a means of accepting electrons transferred away from the necessary oxidation, other than that which involves oxygen as an electron acceptor. Some heterotrophic bacteria achieve this by the simple chemical trick of reducing sulphate ions (SO₄^2-) to sulphide ions (S^2-). This form of heterotrophy does not oxidise carbohydrate back to carbon dioxide plus water, but produces methane. In the context of economic geology, it is the generation of sulphide ions that is more interesting, for any dissolved metal ions will swiftly combine with sulphide to form highly insoluble sulphides—the general form taken by many ore minerals. This is the process observed to occur around deep-ocean hydrothermal vents, where biogenic sulphide ions cause metals dissolved in the hot water to precipitate and form the dark clouds from which such vents get their name—"black smokers". Many metal deposits are now known to have formed in such an environment, notably the volcanogenic massive sulphide or VMS ores.

However, there are many sulphide ores that have no obvious relationship to hydrothermal vents, such as sediment hosted deposits like the massive lead and zinc sulphide deposits of the Mississippi type. Moreover, most sulphate-reducing bacteria are intolerant of oxygen whereas sediment-hosted deposits often bear isotopic witness to the presence of oxygen. But, deposits of that kind often show intricate fine banding, suggesting slow deposition of fine-grained sulphides. Some light is thrown on the problem by a daring piece of research involving sampling from flooded caves in a flooded Pb–Zn mine in Wisconsin (Labrenz, M. et al. 2000. Formation of sphalerite (ZnS) deposits in natural biofilms of sulfate-reducing bacteria. Science, v. 290, p. 1744–1747). SCUBA divers recovered scum formed by bacterial filaments or biofilm, and analyses showed the clear association of the bacterial cells with nanometre-scale spheres of zinc sulphide. The species of sulphate-reducing bacteria involved is not exactly oxygen-loving, but will tolerate moderate levels dissolved in water. Here clearly is a means for the formation of low-temperature massive Pb–Zn sulphide deposits.

The astonishing feature of the results of Lanbrenz and co-workers is that the zinc sulphide forms from water with very low levels of the metal (less than one part per million). The bacteria, or at least their metabolic products, scavenge the metal, and quite probably dangerous cadmium, extremely efficiently. Chances are that similar bacteria could also pick out lead and arsenic. That opens up a new means of bio-remediation—clean-up of both mine waste and contaminated drinking water.

The activity of sulphate reducers leaves its signature on the sulphur isotopes of ancient sediments, revealing periods when the burgeoned, as in Phanerozoic black-shale strata. They were most active in this respect before about 2 billion years ago, when atmospheric oxygen levels were so low as to diminish oxidation by that highly active gas. It seems that sulphate reducers also promote the precipitation of dolomite—(Ca,Mg)CO₃—over that of calcite in sea water. This tallies with the common association of dolomitization of calcite in many sedimentary sulphide deposits, and also with the predominance of dolomites over limestones in the early Precambrian.

See also: Vasconcelos, C. and McKenzie, J.A. 2000. Sulphate reducers—dominant players in a low-oxygen world. Science, v. 290, p. 1711–1712.

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Rhenium fever drives miners into the volcano

November 2000

Satellites demand durable components, and for some applications the metal rhenium is irreplaceable. But it is hard to smelt, as well as being rare. Its current price of US$1.45 per gram reflects its conventional extraction from gases emitted by roasting molybdenum ore, a by-product of copper mining. At around one sixth the value of gold and with work beginning in earnest on the US-Russian International Space Station, a sizeable chunk of rhenium promises a quick profit. For geologists in the economic black hole that was the Soviet Union, rhenium has become a magnet and they are developing possibly the most extraordinary mining venture ever attempted.

Volcanologists of the Russian Institute of Experimental Mineralogy discovered, in 1992, that fumaroles of the volcano Kudriavy in the Kuril Archepelago exhale and precipitate pure rhenium sulphide—the hitherto unknown mineral rheniite. The vents' build-ups contain at least ten tonnes of rhenium, and fumarole gases replenish it at a rate of several grammes each day. As well as mining the vents, even condensing rheniite is an economically attractive proposition. Even now, scientists of the Moscow-based Institute of Mineralogy, Geochemistry and Crustal Chemistry are building a wooden pyramid to cap one of the vents. This will funnel fumarole gases into a chemical trap for rhenium, that uses zeolites as an ion extractor. Future plans, sensibly, focus on concrete or ceramic caps to tap all the fumaroles in Kudriavy's crater.

Source: Jones, N., 2000. Outrageous fortune. New Scientist, 26 August 2000, p 24-26

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20 percent more oil in the ground

A friend from the USA, who visited me a month back, was surprised to find Britain not yet in the throes of a popular insurrection. He gasped each time I filled up at a fuel station. Clearly, he has yet to divine the depth of phlegmatic resources endowed to motorists stuck between junctions 8 and 12 on the M6. Few of us now bother to ponder whether the recent price hikes should be put down to the laws of supply, demand and price, or to the addiction of the British economy to gouging fuel tax and duties from the hapless road user. The Organization of Petroleum Exporting Countries (OPEC) refound its awesome powers of the 1970's during 1998-9 and cut back production to drive a near tripling of spot prices. Concerned that the political impact of this on a now globalized economy might bear down on them, the Saudi delegate to the recent OPEC meeting in Vienna announced an increase in Saudi crude production that halted the upward spiral. Should Iraq be allowed to pump to capacity and Libya reach peak output, the situation would rapidly reverse.

It is a curious time, for the petroleum sector of the North American and European economies faces dwindling home reserves while their industrial production is hard hit by rising fuel prices—a case of 'tails you lose, heads we win', it might seem. Since the Limits to Growth prognosis in the late 1960's of rapid exhaustion of petroleum reserves, each decade has seen the 'evil day' recede into the future, as exploration frontiers have pushed forward and extractive methods become more efficient. In its latest assessment of world fossil-fuel reserves, the US Geological Survey has taken everyone by surprise: http://pubs.usgs.gov/dds/dds-060/

A new approach to estimation using the latest geological data from around the world's petroleum-prone basins suggests that undiscovered conventional oil resources are 20% larger than believed previously. A substantial proportion of this increased estimate stems from evaluating the formerly overlooked tendency for 'finding elephants in elephant country', i.e. hitting previously undiscovered reservoirs within or just beyond existing fields. This suggests that old fields should grow by up to a quarter in the future (612 billion barrels or about 9 years of global production), while new exploration should come on stream with 732 billion barrels, eventually. The estimates are not uniform, however. European and North American production still remains doomed to rapid exhaustion, with the bulk of new resources adding to the already huge dominance of the Arabian peninsula, and to the worrisome former Soviet Union.

Despite the flurry of optimism among petroleum economists and the industry in general, a sober assessment is that the new USGS assessment delays matters by a decade or two at most, given the annual production of 27 billion barrels per year and 1.5 to 2% annual growth—business-as-usual and barely a sign of significantly replacing petroleum with alternative, renewable energy sources that do not add to global warming. Re-emphasis of the overwhelming dominance of the Arabian peninsula, North Africa and the former Soviet Union as suppliers to fuel continuing demand, and the certain increase in one-sideness of the economic relationship have big political implications. Some analysts foresee a 'second coming' of OPEC, and greater tension surrounding the areas formerly in the Soviet sphere of influence. China barely figures as a significant player, despite former optimism.

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Water resources under threat

We now live in an epoch where the 'first provision of any civilized society, after a system of laws, is a water supply' has begun to pass definitively from municipal to privatized control. The private sector in water provision is exploding worldwide, particularly in potentially profitable urban areas of the 'two-thirds world'; i.e. the poorest countries. This is a tendency explicitly encouraged by multi- and bilateral sources of developmental aid, such as the World Bank, departments of the EU and Britain's Department for International Development (DfID). Popular unrest concerning rapidly rising water prices are sweeping through the townships of South Africa and several South American countries, as people find themselves unable to pay for supplies and find them cut off.

The Water Systems Analysis Group of the University of New Hampshire, USA has released a depressing and highly detailed assessment of the future fragility of global fresh-water supplies (Vörösmarty, C.J, et al., 2000. Global water resources: vulnerability from climate change and population growth. Science, v. 289, p 284-288). Their analysis is based on geographic cells half a degree square (about 55 km), and considers the fresh water flow by surface run-off and movement through shallow aquifers, which constitutes the locally sustainable supply (deep aquifers are non-renewable in the short- to medium-term, without being engineered for recharge by surface water) relative to population density and domestic, industrial and agricultural uses. Unlike assessment of petroleum reserves (above), which stems from detailed information supplied by giant transnational companies, doing the same for water is at best a sketchy exercise, because of the wide variations in quality of data.

Using aggregations for individual countries suggests that one third of the world's population lived in 1985 under conditions of water scarcity, and about 450 million faced severe water stress. However, by looking more closely, on a cell-by-cell basis, the Group shows that levels of stress are grossly underestimated by conventional country assessments. They found that 1.8 billion people had to survive 15 years ago at the highest level of water shortage.

To model future changes in water stress, the Group considered both climate and population change. They based the first on a water-balance model that incorporates global hydrological information and the precipitation side of climate change modelling of the anthropogenic 'greenhouse' effect. Climate change is subordinate to growing population and likely shifts in population (the rural to urban drift that is growing at present). Things seem likely to improve for people living in or moving to relatively water-rich areas, but probably at the expense of worsening water quality. The most dramatic feature is a possible 85% increase in the population subject to the highest levels of water stress. Since agriculture that depends on irrigation centres in already water stressed areas for domestic and industrial use, the prognosis is doubly worrisome, since those areas are likely to face even worse food shortages. Looking at individual drainage basins shows that some, including that of the Huang He (Yellow River) in China, which has the highest population density anywhere, seem destined soon to show an excess of demand over discharge.

It is not difficult to foresee from the Group's analysis a rapidly approaching period of curtailment of economic activities, mass migration and conflict in transnational river basins. The danger areas are overwhelmingly in the 'two-thirds world', where the search for profits by water companies finds strategic focuses at present. Being the ultimate in supply-demand forces (demand for water is the least 'elastic' imaginable) this is hardly surprising. It should, however, come as no great surprise if such ventures are expropriated by people themselves.

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