Friday, November 4, 2005 5:28:09 PM
The Tibetan Plateau is often called
the roof of the world, because it not just contains Mount Everest but almost all of the world’s territory higher than 4 km. The hot, molten rocks supporting the plateau are less dense than cold rocks, which means they rise up slowly. Therefore the whole of Tibet could rise up over millions of years since the start of the Cenozoic collision between the Indian and Asian continents about 70 million years ago
New research published in the scientific Journal, Nature, (Nature 438, 78-81 of 3 November 2005) under the title
“Crustal rheology of the Himalaya and Southern Tibet inferred from magnetotelluric data” indicates that a partially molten layer is present along at least 1,000 km of the southern margin of the Tibetan plateau like a gigantic waterbed or hot air balloon supporting the plateau.
See abstract at:
And news at:
See also my blog of Monday, 10 October 2005:
Ole
Thursday, November 3, 2005 8:07:30 AM
Desert roses are rosettes of gypsum crystals with sand inclusions. They form when water evaporates under arid sandy conditions like at the edge of Sahara with its large salt lakes in Southern Tunisia. Sand grains are trapped in the gypsum crystals during their growth and give them the same colour as the sand.
In Tunisia you can buy really nice pieces for less than one Euro or Dollar (or 1 Dinar for that matter). To find them yourself usually need some digging, and knowledge of where to dig.
Gypsum is by the way a hydrous calcium sulphite – CaSO
4.2H
2O. It can be crushed into a white powder and be used in building materials like plaster and sheetrock. Plaster has been used in the Mediterranean region for at least 9000 years – I mean as a building material – I once had my arm in plaster, but that is another story, and of a more recent date.
"Pure" calcium sulphate, CaSO
4, is called
anhydrite, and gypsum is formed by hydration of anhydrate.
Ole
Wednesday, November 2, 2005 9:48:50 AM
I am just back from a 12 days cultural voyage to Tunisia. There is however a bit of geology everywhere, so I might report on that later. Now I have to unpack. In the meantime a pic of a dromedary and me – guess who is who.
Ole
Friday, October 21, 2005 2:42:17 PM
It is not all that simple. Scientists at the
Nansen Environmental and Remote Sensing Center in Bergen, Norway, have found that the Greenland icecap in areas above 1500 meters is thickening by 6,4 cm per year, while (at the edges) in areas below 1500 m above sea level on average 2 cm is disappering each year.
Although this for most people comes as a surprise the thickening seems consistent with theories of global warming. Warmer air, even if it is still below freezing, can carry more moisture. That extra moisture falls as snow below 0°C.
The scientists report their findings online (Scienceexpress of 20 October 2005) ahead of print publication in the journal
Science.
Did you know that you could subscribe to Science Digital for just $99 (VAT excluded). That is cheaper and a lot handier than all that paper.
See also:
The 3,000-metre thick Greenland icecap (
”inlandice”) is a key concern in debates about climate change because a total melt would raise world sea levels by about 7 metres. And a runaway thaw might slow the Gulf Stream that keeps the North Atlantic region warm.
Ole
Thursday, October 20, 2005 7:27:52 AM
Does the world witness more deadly natural disasters?
Does global warming lead to more natural disasters?
Are the natural disasters more deadly because of population growth – in particular in hazardous areas?
Are politicians to blame?
These are certainly important questions?
According to Khaleej Times Online of 19 October 2005 a top scientific group warns of growing natural disasters and the Paris-based International Council for Science has at a meeting in China recommended an international research body be established as a matter of urgency to provide a firmer basis for policies to tackle the problem. The International Council for Science is a non-government organization of experts from around the world.
See
Khaleej Times Online:
http://www.khaleejtimes.com/DisplayArticle.asp?xfile=data/theworld/2005/October/theworld_October508.xml§ion=theworld&col=And if you have never heard of Khaleej Times I can inform you that Khaleej Times is an English language daily newspaper published from Dubai, United Arab Emirates.
In another report on the study and meeting
Reuters know.now at:
http://go.reuters.com/newsArticle.jhtml?type=scienceNews&storyID=9978067&src=rss/scienceNewsstresses that governments too often ignore risks of natural disasters like hurricanes and earthquakes and could save lives and billions of dollars/euros with better planning.
Ole
Wednesday, October 19, 2005 6:53:30 AM
I have a couple of times referred to very old copies of
Scientific American, so now I have better mention the newest October issue!
In the feature article,
“A Cool Early Earth?”, John W. Valley argues that the early Earth cooled down much faster than we were taught until now.
Interesting reading at
http://www.sciam.com/article.cfm?chanID=sa006&articleID=0005FA5D-5F7C-1333-9F7C83414B7F0000&pageNumber=2&catID=2Ole
Tuesday, October 18, 2005 7:59:20 AM
Very appropriately Daily Times (Pakistan) yesterday (17 October 2005) published an article with a reasonable overview of earthquakes, plate tectonics and earthquake predictions.
Daily Times:
It more or less sums it all up.
Ole
Monday, October 17, 2005 12:42:43 PM
So far earthquake engineering (i.e. efficient and economic design of structures that may have to withstand the shaking of earthquakes) risk analysis, hazard maps, land-use regulation, building codes and disaster preparedness have done more to reduce casualties and lower economic losses than earthquake predictions.
In
May 1975 Scientific American wrote the following about earthquake prediction:
“Recent technical advances have brought long-sought goals within reach. With adequate funding several countries, including the U.S, could achieve reliable long-term and short-term forecasts in a decade.”Today 30 years (that is
three decades) later a new report published by
Nature disclosed that a long-term study in the U.S. (California) aimed at predicting earthquakes has ended in a sad failure.
News in Science:
http://www.abc.net.au/science/news/stories/s1481635.htmTo a certain extent scientists can predict location and size, but the timing is obviously a great problem – leaving people in Kashmir and other quake prone regions unprepared.
Earthquake prediction is still an imprecise science.
Ole
Sunday, October 16, 2005 7:28:04 AM
"Popping rocks" off Mexico, near Guadalupe Island, spontaneously explode with a sharp snapping sound when brought to the surface.
The rocks are important because the volcanic gases trapped in the bubbles did not escape during eruption. That could help researchers better understand the origin and history of Earth's atmosphere.
United Press International: http://www.upi.com/NewsTrack/view.php?StoryID=20051014-102334-7476rhttp://allrealnews.blogspot.com/2005/10/popping-rocks-gases-key-to-earths.htmlFor 45 years they have been a geological mystery – since a rock dredge in the early 1960s recovered basaltic lavas that exploded on deck as trapped volatiles escaped from highly pressurized vesicles within the very young rocks; only one other site (in the mid-Atlantic) has such ‘popping rocks,’ which are thought to contain undifferentiated mantle volatiles. As such, this site could be exceedingly valuable for constraining mantle geochemistry and provide insight into mantle processes that occur during oceanic crustal formation.
Ole
Friday, October 14, 2005 2:48:22 PM
Stephen Salter is proposing a fleet of yachts that sprays water droplets into the clouds as the way to damp down global warming. The idea is to boost the whiteness of low-altitude clouds so that they reflect more sunlight back into space. In other words to enhance the so-called
Albido Effect.NewScientist.com news service:http://www.newscientist.com/channel/earth/mg18825213.000
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