Category: Economic and applied geology

The NASA and German Aerospace Centre Gravity Recovery and Climate Experiment (GRACE) launched in 2002 aims to measure variations over time in the gravity field by gauging tiny changes in distance between two satellites using radar. The only significant changes in the short term are due to movements of water in one form or another. The best-known result from GRACE is its assessment of shrinking ice caps, and it can also detect shifting ocean currents and the drainage of lakes. The GRACE science team has noted a major change in gravity since launch over a nearly 3 million km² area of NW India centred on Delhi. The only conceivable mechanism is gradual loss of groundwater though irrigation of the Gangetic plains (Rodell, M. et al. 2009. Satellite-based estimates of groundwater depletion in India. Nature, v. 460, p.999-1002). The authors estimate a decline of around 109 km³ of groundwater since 2002 – more than twice the storage capacity of India’s largest reservoir. In places local farmers are reportedly having to sink deeper and deeper wells as the water table sinks by over 6 m each year. The area is one of Asia’s largest producer of food grains and occupied by 600 million people. Most likely there has been a surge in withdrawal for irrigation during poor monsoons in the early 21^st century, for pumping rates seem to be 70% greater than they were in the 1990s.

 

Gas hydrates soon to come on stream?

 The looming prospects of petroleum production outside of Arabia passing its peak and flexing of Russian economic power that stems from its control of the largest  untapped natural gas reserves are spurring evaluation of methane production from gas hydrates in onshore frozen peat mires and marine sediments. Gas hydrates are more equitably distributed than are much older petroleum reservoirs: even Japan, which is currently entirely dependent on foreign supplies, has what appear to be huge offshore reserves of gas hydrates. Estimates of the world‘s potential resources are enormous, at around 2 x 10¹⁶ m³ (annual US natural gas consumption is ~ 6 x 10¹¹ m³) but in a variety of sands and muds at different concentrations (Boswell, R. 2009. Is gas hydrate energy within reach? Science, v. 325, p. 957-958). Experiments in northern Canada (see Onshore gas hydrate reserves close to recovery in March 2004 issue of EPN) indicates that drilling to induce lower pressure in gas hydrate bearing sediments induces dissociation of the hydrate crystals to release methane while retaining also present within their structure. Injection of CO₂ into deposits should displace methane while CO₂ enters the crystalline structure: killing two birds, including carbon sequestration, with one stone. The main technical stumbling block is that gas hydrates occur in unconsolidated sediments that may be destabilised during production, resulting in uncontrollable release of the powerful greenhouse gases as well as collapse of surface structures. From an environmental standpoint, all gas hydrates do is sustain reliance on carbon-based fossil fuels and continue emissions of greenhouse gases, though burning methane is a good deal ‘cleaner’ than coal or oil.

Maybe it was a coincidence, but the April issue of Geology contain a paper whose title looked suspiciously unreal (White, K. et al. 2009. Hydrologic evolution of the Edwards Aquifer recharge zone (Balcones fault zone) as recorded in the DNA of eyeless Cicurina cave spiders, south-central Texas. Geology, v. 37, p. 339-342). Seemingly, the Cretaceous Edwards Aquifer now flows through cavern systems at the base of a fault-controlled escarpment. At higher levels in the unit are air-filled caves, that are relics of previous karstic events. It is in these dark, dry caves that the arachnid troglobites dwell. Troglobitic animals (those that inhabit totally dark caves and have no eyes) originate as normal surface dwellers, which through successive generations lose functioning eyes and coloration. Conversely, they evolve improved senses of smell, taste and vibration detection. The species that emerge are among the rarest of creatures, for they often occur in only a single cave: a special case of allopatric speciation that may happen when small populations are cut off from one another. Technically, then, this study is no joke, for analysis of mtDNA from the spiders in different caves ought to show evidence of microcosmic evolution, and possible provide a molecular ‘clock’ to chart the times of cave colonisation. And this is what the authors from the University of Mississippi and the endangered invertebrate group of a Texan consulting company have tried to do. The spiders in the higher caves are more evolved than those at progressively lower levels. Moreover, since the karst evolution has developed in a structurally active setting, the spider data correlates with tectonic history…

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.

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.

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 — it is also one of the largest, with reserves of around 1300 tons (~41 million troy ounces). There, gold is being extracted from an open pit, cooled by water injection, in the crater of a geothermally active volcano. Aside from that 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, and 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 trns out to be 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 it is derived directly from magma. The fluid is 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 rapid 55 thousand years at the 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 tone of gold every year. However, before setting off on a gold rush to extinct volcanoes in the 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 in such a vast volume of rock that its extraction is not economic.

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.

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.

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.

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.

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.

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.

In their slack moments, petroleum geologists ponder on when oil and gas got into a particular reservoir and became trapped.  One aspect of the conundrum is easy to answer: after the reservoir rock and trap formed.  But timing is not so trivial, for an important consideration in exploration for new oilfields concerns the actual rock that sourced hydrocarbons in known fields, almost always a highly reduced, black mudrock in which unoxidised dead organic matter accumulated and matured. Repeated anoxic events, both regional and global, provide several alternatives in many petroleum provinces.

Hydrocarbons, having formed under highly reducing conditions, contain several metals and other elements well above normal crustal concentrations.  Among these are rhenium and osmium, which allow radiometric dating through the decay of ¹⁸⁷Re to ¹⁸⁷Os.  In principle, therefore, it is possible to date oil and relate it to a particular source rock. Interestingly, it is easier to date the actual time at which oil has accumulated in a trap.  In an analogous way to the equilibration of parent and daughter isotopes in magmas, which is halted by crystallization so that the system evolves and dating can be done, once oil settles in a trap after migration the timing can be dated sing the Re-Os method.  David Selby and Robert Creaser of the University of Alberta, Canada applied this approach for the first time, using the vast reservoirs of oil sand in Alberta as a test (Selby, D. & Creaser, R.A. 2005.  Direct radiometric dating of hydrocarbon deposits using rhenium-osmium isotopes.  Science, v. 308, p. 1293-1295). The oil in the sands were emplaced around 112 ±5 Ma ago, during the Early Cretaceous, not long after the host sandstones had been deposited.  Previous work using ideas on oil maturation suggested that migration had taken place during the Early Palaeocene, around 60 Ma ago, when potential source rocks were heated by tectonic burial during the Laramide orogeny.  The Re-Os results point to migration from the west while the Cretaceous sedimentary basin was filling.  This may explain the high viscosity of the oils as a result of near-surface biodegradation.

Another product of isotopic dating is establishing the initial ¹⁸⁷Os/¹⁸⁸Os ratio of the petroleum system, which relates to that of the original source and its isotopic evolution.  In the case of the oil sands this value points to source rocks of earlier Mesozoic and even Palaeozoic age, rather than a Cretaceous source that had been suggested previously.

On May 24 the government of Tanzania cancelled a contract with the commercial water giant Biwater, which was supposed to bring clean water to the country’s largest city Dar es Salaam, and establish a privatised water supply.  The UK-based company had won a £76.5 million contract from the World Bank, with the support of the British government’s Department for International Development (DfID).  DiFID had paid the free-market thinktank £0.5 million in fees to advise the Tanzanian government and promote privatisation, out of a total expenditure of more that £36 million since 1998 for similar consultancies.  In two years Biwater has failed to install a single pipe (Vidal, J. 2005.  Flagship water privatisation fails in Tanzania.  The Guardian 25 May 2005, p. 4).

In her statement to the International Conference on Water and Sustainable Development in Paris (March 1998) Clare Short (British minister then heading DfID) outlined the New Labour government’s “vision” on water resources in the Third World, “Partnerships among governments, the private sector and civil society are critical to sustainable development [of water resources]”.  Policy of the International Monetary Fund is to enforce “structural adjustment programmes” on poorer countries as a condition for rescheduling debt repayments. Into these are written the privatisation of formerly public assets, such as water utilities. The first targets for this in Africa were the townships of South Africa, following the removal of apartheid.  Although very poor by western standards, and with unemployment running at up to 50%, people in South African townships are better off than the majority of sub-Saharan Africans.  Potential profits from water metering seemed attractive.  However, a great many people found themselves cut off from this most basic necessity in 2000, being unable to pay the increased water rates.  This led to nationwide protests, the most violent being in the arid Transvaal.  The company involved in that region was also Biwater, with bids for contracts worth 12 billion rand.  The company has an interesting history, having been an early beneficiary of the Conservative government’s “aid for trade” programme in the 1980s, including dam and water distribution contracts in Malaysia and Thailand that were linked to British arms supplies to the governments involved.

Water privatisation is a target outside Africa, perhaps the most notorious case being in South America. Bolivian trades unionists demonstrated on 6 April 2000 against a 35% rise in water prices imposed on the city of Cochabamba.  Military forces opened fire, killing 6 demonstrators, and a state of siege was declared by the authorities. The price hike stemmed from the new owner of the region’s water system – International Waters Ltd (IWL) of London, a subsidiary of Bechtel, based in San Francisco.  IWL’s Bolivian operation centres on the Misicuni dam project.  Water from the dam will cost 6 times more than it would from alternative sources.  The increased water charges were to recover the cost of the dam, with one problem: the dam had not been built, and IWL/Bechtel had put no funds into the construction project.  Subsequently, public pressure forced the ending of the contract.  Similar upheavals have been seen in Ghana, Trinidad, Argentina and the Phillipines.

News of Tanzania’s decision to end the ill-fated contract with Biwater followed announcements in the same week that the EU would effectively double its Third World aid.  In early July, Britain will host the 2005 G8 summit, which will be dominated by discussion of ways to increase the flow of finance into Africa in particular.  This follows the publication in early 2005 of the Commission for Africa Report sponsored by the New Labour government. Two thirds of the world’s population lacks sanitation that is adequate for healthy living.  Of them, one billion people, including the majority of Africans, have no access to safe drinking water.  Poor water supplies form the main contributor to the death of children under five years old.  For hundreds of millions of people, getting water for domestic use consumes much of their daily labour, which involves mainly women and children trudging to distant water sources and carrying it home, on average twice each day.  The failure of private enterprise to deliver water to the needy suggests that the small print of any declaration from the G8 summit needs the most careful scrutiny.

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

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 CO₂ 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 CO­₂ emission plus the effect on the environment of so much sulphate and a massive fall in pH.

The US oil economist M.K. Hubbert issued a chilling warning in the late 1960s that foretold the eventual decline of the single most important physical resource of the global economy.  His simple approach was to consider petroleum, and by implication a great many other commodities, as having a fixed abundance that was not added to naturally at a rate that could keep pace with its exploitation.  Oil and natural gas are non-renewable, as far as human society is concerned; they are “wasting” resources built slowly and episodically over tens of million years.  Hubbert matched the exponential rate at which petroleum is extracted with various notions of how much is in the ground and how the easiest to find and pump out inevitably will give way to more tenacious reserves.  His model for the future of the petroleum economy centred on a theoretical bell-shaped curve relating production to time, and we are now entering his predicted period of increasing difficulties.  Estimates of reserves have increased considerably in the last 35 years, and so has the efficiency of getting out the fluids.  Recent news leaking from the Shell oil giant that there has been a certain fiddling of the books about how much remains in its licence areas (a 20% overestimate) is perhaps a sign of just how difficult it is to keep pace with growing demand.  Oil companies hope for the best as regards how quickly new discoveries add to their assets, yet they can never voice their fears of the worst for the sake of investor confidence and the volatility of the oil futures market.  The history of petroleum discovery is indeed a bell-shaped curve, and it has been on the slippery downward slope for about 30 years, with a few cheering but brief upswings.  On average, annual discovery has decreased from about 50 to 10 billion barrels each year, noting that the size of the discoveries is always an estimate of what might eventually be extracted to be tempered by the fact that it rarely if ever is.  A great deal of the petroleum products now being used emerge from massive discoveries in the late 30s and 40s and the mid 1960s.  Nothing like the huge Arabian and Iraqi fields has been found since then.  Many commentators, as usual, consider the present upsurge in oil prices to stem from political issues, but there are deeper economic and technical issues that suggest that it is an irreversible trend while ever demand is insatiable and supply more difficult to achieve.  Standing above the generally quoted reserves that can reasonably be expected to flow using current methods, are several categories of petroleum in the ground that require new extraction methods and a higher price to implement them.  They are considerably larger, though much more fuzzily defined, and range from the dregs that are not easily pumped, through viscous oils, tars sands to oil shales, the primary source rocks for conventional petroleum fields when geological processes free their organic content to move.  So the future is likely to depend increasingly on new extraction technologies, that Jim Giles of Nature recently reviewed (Giles, J. 2004.  Every last drop.  Nature, v. 429, p. 694-695).  There are several problems to solve in boosting production: decreasing the viscosity of oil, freeing oil that remains in sediment pore spaces, and driving the oil out under pressure.  One interesting possibility is setting fire to oil in the reservoir rock, by pumping air into it.  That would create gas pressure as well as lower viscosity, and has been tried before after Russian engineers accidentally set fire to a deposit by trying pressurised air to drive oil out.  Following their surprise (and no doubt a ticking off by top political management), oil did flow more freely from nearby wells, but later experiments have had mixed success.  Bacteria that metabolise oil are increasingly used to clean up spills.  Since they break it down to lighter and less viscous molecules, and generate various gases, they have a role to play underground.  However, all kinds of secondary recovery methods that are deployed today do not add a great deal to production – about 3 to 4% – and are unlikely to stave off eventual decline without further massive increases in price.

Structural control over hydrothermal gold mineralisation

One of the world’s richest gold provinces is centred on the town of Kalgoorlie in Western Australia, site of the “Golden Mile” whose production and reserves exceed 2500 tonnes of gold.  The geological control is a 200 km long shear zone trending SSE that cuts Archaean greenstone associations of mafic-ultramafic and felsic lavas, and volcanoclastic rocks of the 2700 Ma Yilgarn Province.  Exploration along the trend has revealed a number of other world-class gold deposits, and the Boulder-Lefroy Shear Zone has come to typify syn-tectonic hydrothermal mineralisation.  Detailed work has long demonstrated that smaller shear zones slightly oblique to the main trend focus the mineralisation.  That is because the main line of movement was probably in compression, having a strike-slip sense of motion.  Depending on the local orientation of lesser shear zones, some have trends likely to have encouraged dilatation in transtensional environments.  Fluids are more likely to favour such opening zones, thereby concentrating their flow and deposition of minerals from them.  Much of the research in the area has focussed on detail, in an attempt to discover a means of predicting new deposits, and exploration is dominated by systematic drilling in what is not a particularly well-exposed terrain, and one where standard methods of stream sediment analysis are thwarted by low rainfall.  Robert Weinberg of Monash University, Paul Hodkiewicz and David Groves of the University of Western Australia have taken a broader view of the structural setting (Weinberg, R.F. et al.  2004.  What controls gold distribution in Archean terranes?  Geology, v. 32, p. 545-548).  So intensively explored is the gold province that it is unlikely that any large deposits remain to be discovered, but very similar shear zones affect most of the world’s Archaean granite-greenstone terranes, where exploration is at an earlier stage of progress.  A model of regional controls over gold is therefore pretty valuable.  Weinberg et al. divide the Boulder-Lefroy Shear Zone into boxes along its length, each centred on 8 gold “camps”.  They plotted the deviation in trend of local segments of the shear zone in each box from its overall trend against the box’s known gold “endowment”.  What emerged was a clear confirmation of the regional association of mineralisation with  likely zones of regional transtension, trend deviation matching closely the estimated gold endowment.  The abundance of structural data also enabled the authors to analyse the fractal dimension of all shears and fractures, thereby assessing the variation in overall geological complexity of the province.  The results are odd.  The least well-endowed parts of the gold province are more complex than those containing the most gold.  The Golden Mile itself occurs where complexity changes from low to high. The ideas await testing on less mature shear zones cutting Archaean greenstones elsewhere in the world, such as in South India and East Africa.

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. 303, p. 946-947

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.

Background to globalisation of water resources

“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)

Oil and natural gas are the dominant physical resources for modern society, having rapidly outstripped coal in the world’s economy.  Yet using them poses the threat of global climatic changes.  They are essentially a bank of solar energy, mediated by past photosynthesis into hydrocarbons; very long passed indeed.  Their burial tens and hundreds of million years ago helped modulate solar warming and drove up the level of oxygen in the atmosphere.  Using them reverses those aspects of the carbon cycle.  As the wars in Sudan, Afghanistan and Iraq demonstrate, developed economies will go to any lengths to retain access to known reserves.  Being so “hooked” on hydrocarbons, those economies have continually to find more.  However, the days of “trip-over” oilfields, such as those of Persian Gulf, are gone forever.  Exploration ventures into more and more difficult conditions, particularly offshore, where drilling is now going on in sea floor as deep as 2.5 km beneath the water surface.  Every aspect of the hydrocarbon industry poses increasing challenges; it seems to be at a crux.  For this reason, the 20 November 2003 issue of Nature includes a 56-page Insight supplement on a wide range of topics.  It starts with a review of the place of the petroleum industry in human history (Hall, C. et al. 2003.  Hydrocarbons and the evolution of human culture.  Nature, v. 426, p. 318-322).  Robert Berner of Yale University gives an up to date summary of the effects of fossil fuel use, in the context of the carbon cycle over geological time (Berner, R. 2003.  The long-term carbon cycle, fossil fuels and atmospheric composition. Nature, v. 426, p. 322-326).  The question, “How does petroleum form?” is addressed by Jeffrey Seewald of the Woods Hole Oceanographic Institute (Seewald, J.S. 2003.  Organic-inorganic interactions in petroleum-producing sedimentary basins. Nature, v. 426, p. 327-333).  The shift of exploration to ever deeper offshore areas brings it closer to the lines where continents split and drifted apart in the past.  So it isn’t surprising that Nature Insight includes a review by Cambridge University and BP geoscientists of how those margins evolved (White, N., Thompson, M. & Barwise, T. 2003.  Understanding the thermal evolution of deep-water continental margins. Nature, v. 426, p. 334-343).  Organisms other than humans exploit the energy locked in oil, and geochemists from the University of Newcastle upon Tyne address their role in actually degrading petroleum, so that many of the largest onshore petroleum reserves (oil sands in particular) pose great difficulties for exploitation (Head, I.M., Jones, D.M. & Larter, S.L. 2003.  Biological activity in the deep subsurface and the origin of heavy oil. Nature, v. 426, p. 344-352).  Methane generated by anaerobic bacteria in sea-floor sediments and in bogs can combine with water in the form of an ice-like substance called methane hydrate, if the pressure is high enough and temperature is close to 0ºC.  There is a lot of it about.  On the one hand it has huge economic potential, but on the other it poses awesome threats to the climate.  Several times in geological history vast amounts of methane have belched from the sea floor to drive up global temperature; it is a highly efficient “greenhouse” gas.  Dendy Sloane of the Colorado School of Mines addresses issues related to methane hydrates (Sloane, E.D. 2003.  Fundamental principles and applications of natural gas hydrates. Nature, v. 426, p. 353-359).  All these articles are deeply informative and well written.  They are “must-reads” for all geoscientists.  The sequence ends with a word from “management” (Shell International), in the form of a look ahead to how oil companies might clean up their act and become “friends of the Earth” (Stankiewicz, B.A. 2003.  Integration of geoscience and engineering in the oil industry – just a dream? Nature, v. 426, p. 360-363)

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

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.

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:  Coghlan, A 2003. All hooves to India’s pumps.  New Scientist, 10 May 2003, p. 19.

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.

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.

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!