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The Permian-Triassic extinction event, sometimes informally called the Great Dying, was an extinction event that occurred approximately 252 million years ago, forming the boundary between the Permian and Triassic geologic periods. It was the Earth's most severe extinction event, with about 96 percent of all marine species and 70 percent of terrestrial vertebrate species becoming extinct.

Scientists are still arguing why it happened, and the Siberian Traps have been one of the main suspect - although the causal mechanisms remain disputed.

Svensen et al. have come up with a new hypothesis in a paper titled “Siberian gas venting and the end-Permian environmental crisis”, published in Earth and Planetary Science Letters of 30 January 2009.

The hypothesis can be summarised in 3 phases:
1) Emplacement of magmatic intrusions (sills) into organic rich sediments and evaporites (252 million years ago)
2) Contact metamorphism lead to gas generation (transformation of organic carbon to gas like CO₂, CH₄, CH₃Cl) and over-pressure.
3) The gas was released to the atmosphere through enormous vertical pipes. The gas gave rise to global warming and destruction/depletion of the (life protecting) ozone layer.

* The original coverage with flood basalt may have been as high as 7 million km². The original volume of lava has been estimated to range from 1 to 4 million km³.
* Enormous volumes of Cambrian evaporites are present in the Tunguska Basin, with up to 2.5 km thick sequences of halite-rich strata, anhydrite, and carbonates. Furthermore the basin was petroleum-bearing prior to the end-Permian sill emplacement - with a large carbon gas production potential.
* More than 500 basaltic diatreme-like pipes are known in the northern parts of the Tunguska Basin, and the authors estimate that there is about a total of 6400 pipes in the basin. (A diatreme is a breccia filled volcanic pipe formed by a gaseous explosion)

The authors argue that the composition of the heated sedimentary rocks below the flood basalts is the most important factor in controlling whether a Large Igneous Province (like the Siberian Traps) causes an environmental crisis or not. They propose that a similar mechanism could have been responsible for the Triassic-Jurassic (~200 Ma) global warming and mass extinction, based on the presence of thick sill intrusions in the evaporite deposits of the Amazon Basin in Brazil. The end of Triassic mass extinction (about 200 million years ago) is the second largest known mass extinction event. The flood basalts of the Central Atlantic Magmatic Province (that might have released sufficient volumes of gasses for a mass extinction 200 million years ago) are difficult to explore with most of the clues hidden under the Amazon rain forest.

The second biggest known extinction at the Triassic–Jurassic was contemporaneous with the formation of the Central Atlantic Magmatic Province in the eastern US, South America, and western Africa - during the breakup of Pangaea. Thick sills are common in this province, emplaced in thick Permian evaporite deposits in the Amazon Basin in Brazil. Here too the authors propose that evaporite metamorphism caused generation and venting of carbon gases and halocarbons to the atmosphere, leading to global warming and atmospheric ozone depletion. The Amazon Basin needs to be investigated in detail to lend support to this hypothesis. To the authors the fact that the two biggest mass extinctions the last 252 million years occurred at the same time as two major sill emplacement events into evaporite basins, seems to be too much of a coincidence.

Reference:
Henrik Svensen et al.
Siberian gas venting and the end-Permian environmental crisis
Earth and Planetary Science Letters 277 (2009) 490–500.
doi:10.1016/j.epsl.2008.11.015

• http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V61-4V69JGV-3&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=0122cc9290ee1b383c98efd1bcafd16a

In Norwegian:
• http://www.geo365.no/forskning/masseutryddelse/

An increasing number of geological elements have been added to the wonderful world of Google Earth. On Google Earth you can see for instance earthquakes, volcanoes, and plate tectonics in their right geographic context.

But there is even more to it than that, and I would like to draw your attention to the following recent geoblog posts on this topic (how to use the resources and how to add/get more):
• http://magmacumlaude.blogspot.com/2009/02/using-google-earth-to-visualize.html
• http://shearsensibility.blogspot.com/2009/02/google-earth-explosion.html
• http://ron.outcrop.org/blog/?p=323

And a few other interesting links:
• http://www.volcano.si.edu/world/globallists.cfm?listpage=googleearth
• http://www.geology.sdsu.edu/localgeology/getour.html
• http://serc.carleton.edu/NAGTWorkshops/structure/google_earth_mapping_locations.html

It is important to incorporate feedback loops in climate models. Feedback can be positive or negative.

Positive feedback: The formation of ice will increase the albedo^*) of the surface so more incoming short wave radiation will be reflected from the surface, this will cause the surface to cool. This additional cooling could allow more ice to form increasing the surface albedo even more. This will in turn cool the surface and the climate will have entered a positive feedback.

As polar ice starts to melt the opposite happens. The ice is darker in color than the snow. Melt ponds and cracks form in the ice, which are also darker in color. And where the ice has melted, dark ocean water is exposed. These changes decrease the albedo. With a lower albedo more solar energy is absorbed and less is reflected. This causes more ice to melt, which in turn lowers the albedo, causes more energy to be absorbed and more warming to occur. (This is by the way also positive feedback).

In short melting ice causes more ice to melt, and this effect seems to have been underestimated in climate models so far.

A research team has now come op with relevant (more correct) sea ice-albedo data for use in global climate models. Their work will later be published in the Journal of Geophysical Research (“A new sea ice albedo scheme including melt ponds for ECHAM5 GCM” by Christina A. Pedersen et al.).

The average temperature in the Arctic has increased at twice the rate of the global average the last 100 years, and with the increased warming, substantial decrease in both sea-ice extent and thickness has occurred. Particularly, the September minimum sea ice extent in the Arctic has declined by about 8% the last 30 years. Although the models used in the Intergovernmental Panel on Climate Change (IPCC) reports show recent declining Arctic sea ice extent, none of the models show trends comparable to the recent observations. The team that has investigated melt ponds on sea ice surface believes one of the reasons can be shortcomings in the description of the energy balance in the models. The melt ponds substantially reduce the surface albedo and absorb two to three times more solar energy compared to thick bare sea ice. The overall effect on the sea-ice albedo is largest in summer, with average reductions of 23% in the northern hemisphere in August. In the southern hemisphere the overall effect is smaller. The effect of reduced sea-ice albedo is overall reduced sea-ice thickness, concentration, and volume, with large temporal and spatial variations.

• http://www.ssf.npolar.no/pages/news268.htm

In Norwegian:
• http://www.aftenposten.no/nyheter/miljo/article2913936.ece#xtor=RSS-3

*) Albedo:
Albedo is the fraction of solar energy (shortwave radiation) reflected from the Earth back into space. It is a measure of the reflectivity of the earth's surface. Ice, especially with snow on top of it, has a high albedo: most sunlight hitting the surface bounces back towards space. Water is much more absorbent and less reflective. So, if there is a lot of water, more solar radiation is absorbed by the ocean than when snow or ice dominates. The word is derived from Latin albedo "whiteness", in turn from albus "white".

PS: See also Arctic Heats Up More than Other Places from USGS Newsroom


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When I was young I thought that if you had sand, you made a sand pit, if you had clay you made bricks, if you had gold you dug it out, if you had oil you pumped it up etc.

A quick glance at the following overview of lithium production from the U.S. Geological Survey, Mineral Commodity Summaries, January 2009 demonstrates that this is not always true.


High in the Andes, in a remote corner of Bolivia, in Salar de Uyuni, the world’s largest salt flat, lies more than half the world's reserves of lithium, but the output is zero.



Lithium salts are found in evaporites and salt lakes. Subsurface brines have become the dominant raw material for lithium carbonate production worldwide because of lower production costs as compared with the mining and processing costs for hard-rock ores. Two brine operations in Chile dominate the world market; a facility at a brine deposit in Argentina produces lithium carbonate and lithium chloride. A second brine operation is under development in Argentina.

The market for lithium compounds with the largest potential for growth is batteries, especially rechargeable batteries. Non-rechargeable lithium batteries are used in calculators, cameras, computers, electronic games, watches, and other devices. Demand for rechargeable lithium batteries continues to grow for use in cordless tools, portable computers, mobile telephones, and video cameras. Future generations of electric vehicles may use lithium batteries (so-called lithium-ion batteries). Mitsubishi, which plans to release its own electric car soon, estimates that the demand for lithium will outstrip supply in less than 10 years unless new sources are found.

Lithium is a limited resource and may one day be as important as to-days oil. Bolivia can become the Saudi Arabia of lithium, but for the time being it is waiting - hoping for even better times. At the same time geologists and economists are debating whether the lithium reserves outside of Bolivia are enough to meet the climbing global demand.

President Evo Morales is an ardent critic of the United States and has already nationalized Bolivia's oil and natural gas industries. For now his government talks of closely controlling the lithium itself and keeping foreigners at bay. The indigenous groups in the remote salt desert where the mineral lies are pushing for a share in the eventual bounty. Their grandparents lived on the salt. They arrived from the valleys in caravans of llamas, but the market forced them to leave. Now they want to return to live on the salar and to improve their living conditions.

I call it high stake gambling and hope for the Bolivian people that they do not become the losers in their president's gamble.

Rest to say that lithium plants produce sulphur dioxide which is a pollutant.

• http://news.bbc.co.uk/2/hi/business/7707847.stm
• http://www.nytimes.com/2009/02/03/world/americas/03lithium.html?_r=1
• http://www.iht.com/articles/2009/02/02/america/lithium.4-421488.php
• http://seekingalpha.com/article/118098-lithium-bonanza-in-bolivia

In Danish:
• http://ing.dk/artikel/95515


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