Geology news

Water and Ocean Currents

At there is another ESA report - this time on the role of the Amazon and the Orinoco in the Ocean Circulation system in the South Atlantic. Fresh water from the Amazon tends to create a flow or current of low salinity surface water. It seems to circle back on itself as a result of a much stronger ocean current off the coast of northern Brazil which is the southern equivalent of the North Atlantic's Gulf Stream - and well recorded in ocean circulation research.

The Antarctic of the Past

At is a strange title as it gives the impression a paper with a lead author from the British Antarctic Survey was referring to the continent of Antarctica dissected by a waterway - when in fact they were saying no such thing.

San Andreas Fault ... tremblors going back 700 years

At earthquakes have been a regular feature along the San Andreas fault system for a long time and a series of tremblors have been charted over the last 700 years. The September issue of Geology says that large ruptures have occurred on a stretch of the fault 100 miles NW of Los Angeles (where the research took place), at a rate of between 45 and 144 years apart. The last really big quake was in 1857, over 150 years ago.

K/T boundary event - a compromise?

BBC News August 30th ... the K/T boundary event, it seems, involved more than one meteorite, or asteroid strike, according to a new study in the journal Geology by Professor David Jolley at Aberdeen University. The Boltysh Crater in the Ukraine was first reported (in the west) in 2002 and scientists have now examined pollen and spores of fossil plants in the layers of mud that have infilled the crater. They found that immediately after the impact ferns quickly colonised the davastated landscape.

The Layer Cake

If this is cake it ain't got a lot of fruit. At ... research has found the North American continent is a layer cake (see Nature August 26th). Exploration of seismic factors at the interior of the earth illuminate how the continents formed. The continental land masses have been broken into pieces, joined back together, and then broken up again - but some old pieces of the lithosphere have existed over very long periods of time.

Some further catastrophic web sites

At ... Dennis Cox suggests naming post impact plasma vortice of large airburst impact events which are commonly mistaken as ignimbrite, or volcanic tuff, as infernignite. This, he says, is impact melt formed when a terrain is flash melted, ablated, and forged by intense heat and the pressure of the vortice. Infernignites, he goes on, are formed and emplaced in an atmospheric pressure driven scenario and resemble a pyraclastic flow.

Sea Level around the coast of Britain in the Holocene

Ian Shennan of the Sea Level Research Unit at Durham University has written and co-authored a number of books and articles on the subject but as with all modern science, computers have predictably been seconded to provide a knowledge base, and modelling, as always, has been developed as an aid to see how small changes over many years may have panned out at different points in time. There is of course nothing wrong with that - it is an extremely useful tool, supposing all the information is fed into the models.

Mud volcanoes on Mars

At ... in the August issue of Icarus there is a paper claiming some 18,000 circular mounts have been mapped on Mars in a region that might have as many as 40,000 of them. They used images from the Mars Reconnaissance Orbiter, and think they might actually be mud volcanoes. These are geological structures in which a mixture of gas, liquids and fine grained rock (mud) is forced to the surface from serveral km underground.

No One Has Ever Been Here - where? August 13th ... George Howard has a couple of pictures of craters on the Gilf Kahir plateau in the Egyptian Sahara, near the border with Libya. Norbert Brugge, a German geologist, said 'no one has ever been here!' What he means is that no geologist or anyone with a camera has visited the site, and George laughs, it 'only reinforces my belief that people (scientists as well as the general public) overestimate what we know and vastly discount what we do not'.

An Indonesian glacier

At we have an interesting story about a shrinking glacier on a 16,000 feet high Indonesian mountain ridge that is disappearing - rapidly. The glacier is another victim of AGW according to the bumph (supported by a National Science grant). Three cores have been drilled out of the glacier and it is hoped evidence of past climate change will emerge that might throw some light on the ebb and flow of El Ninos, for example, as well as past cooling and warming episodes.