Geology news

Arabia in the Past and Tibet in the Past

The first story is at www.dailygalaxy.com of May 1st (direct link does not work so go to site and trawl down menu) ... satellite images have revealed an ancient network of rivers and streams in the Arabian desert, indicating the region was much wetter in the past - as we already know. However, it is not the first half of the Holocene that interests anthropologists and geologists at the moment, but Arabia during the Pleistocene and the assumed passage of humans Out of Africa.

The Tibet plateau and the origin of loess

At http://phys.org/print254405062.html ... when did the desertification as a result of the uplift of the Tibetan plateau happen. Geologists are divided. One view is that it occurred 22 million years ago, at the onset of the Miocene, when it seems the plateau began to rise - slowly. The plateau, as it rose, stopped the flow of moist air from the south, is the basic ingredients of the theory, leading to increasing amounts of desertification. It seems that the desert conditions are required in order to explain another theory, on the origin of loess by the wind.

Glass on Mars

At http://news.discovery.com/space/mars-dark-spots-120402.html ... a piece on the discovery of glass on the surface of Mars - and explanations offered. Dark patches visible across much of the northern hemisphere of Mars are not canals or other geological features as once thought, in the dimmer past, but volcanic glass - via data from ESAs Mars Express Orbiter. It is unclear if this is glass as we might understand it or something else. It is also described as basalt - and basalt has an origin in magma from volcanic and seismic activity.

Sahara Sand

Gary has sent in a couple of links that people may find stimulating - Sahara sand under the microscope. See http://vixra.org/pdf/1102.0022v1.pdf and www.myspace.com/jonlarsenguitar/photos/51836900

The mystery is there are micrometeorites in sand - in desert soils, in beach sand, and in glaciers. The deposition of micrometeorites can be found vritually anywhere - even in downpipes from the gutter of your house. Iron micrometeorites can be found with a magnet.

Wandering continents

NASA sicentists have been looking at how continents wander and plate tectonics in general - see www.sciencedaily.com/releases/2012/03/120322161938.htm. A layer of partially molten rock deep underground is thought to be the mechanism that allows continents to wander - or plates. What else might be going on? Seismometer data suggests this layer is patchy - especially under the Pacific Ocean.

Big Game hunting game

The climate versus human hunter theory has surfaced once again in Australia and once again achieves very little in settled science but does manage once again to denigrate the Aboriginal population - see www.physorg.com/print251656739.html. A team of scientists from six universities say they have put an end to the long running debate - a bit of wishful thinking, perhaps. Hunters, they claim, killed off the large herbivores such as giant wombats and the like and shortly afterwards, there was a rapid shift in climate, caused by guess what, the lack of herbivores to munch the vegetation.

A big lump of sand in the North Sea

A ten cubic km wedge of sand now exists in the northern North Sea basin, somewhat south of Norway and east of Scotland, enough to bury Manhattan island under 160m of sand or the whole of London under 6m of sand (and that is an awful lot of the stuff). It appears to be extrusive - rising up from the gizzards of the earth. The paper is in the journal Geology March 19th but the big question might be - if sand is formed from eroded rocks why was so much of it buried under the sea floor?

Global Sea Levels

Global sea levels are pretty well flat at the moment but a paper in the journal Geology is not at all discouraged by this and assures us one and all that they are set to rise by 40 to 70 feet - see www.physorg.com/print251376839.html. Part of the research was done on a coral atoll in the Pacific and some of it in the seismically active area of New Zealand and soil cores taken from Virginia were also used - but it is unclear if any of this has a bearing on the conclusions.

Sicily to Tunisia

In a book picked up from a charity shop, Art and History of Egypt by Alberto Carlo Carpiceci, it begins with some extraordinary geological information on the Mediterranean basin. The Italians would be more concerned with this part of the world than people over against the Atlantic seaboard. It says that in the Palaeolithic era the Mediterranean Sea was cut into two basins - divided by a tongue of land that joined Tunisia and Italy, the islands of Malta being a remnant.

Subduction

The Mariana Trench in the Pacific has been mapped (mentioned in an earlier piece) with ultrabeam sounding technology and scientists, subsequently, have measured the depth - roughly 11000m. However, it is the discovery of four bridges spanning the trench that is most surprising and they are thought to be caused by one plate descending into the hole and becoming snagged when the sea plate subducting has sea mounts. There are lots of sea mounts on the Pacific plate and are as much as 2500m high.