Geology news

Eocene anomaly and sea floor spreading ... again

This time, a paper in Nature July 7th (see www.physorg.com/print229175772.html ) that claims not just push and pull at plate boundaries are responsible for tectonic events but plumes of hot magma rising up from the deep interior of the earth play a role in plate tectonics - but what might cause such upwellings is something else.

Sea Floor Strips

Musings from the Chiefio, July 4th 2011 (http://chiefio.wordpress.com/2011/07/04/why-does-the-sea-floor-move-in-s... ... EM Smith looks at consensus theory on sea floor spreading, mainly in the Pacific as he lives in California, and finds some apparent anomalies. This is a not a serious study of sea floor spreading but the blog author just playing around with an idea. He therefore does not reach a firm conclusion - merely points out that the sea floor itself may move, in pieces, but not necessarily in a uniformitarian pattern.

Under the sea volcanic activity

An interesting post at http://chiefio.wordpress.com/2011/06/24/megaplumes-and-volcanic-gasses/ is a bit of typical sleuthing by EM Smith, wondering just how much co2 might be produced by under the sea tectonics and volcanic activity. He takes it a stage further by speculating that it might influence the transfer of heat by the ocean circulation system that runs around the globe, an area of research that is poor in comparison with other palaeo-climatic endeavours.

The St Kilda archipelago

BBC News (see www.bbc.co.uk/news/uk-scotland-highlands-islands-13753643?print=true ) on June 17th reported on archaeologists discovering an extensive field system and terraces cut for cultivation on Boreray, a small island in the archipelago. The evidence was covered in turf and soil but is unmistakable - at some point in the past farmers lived on this small outcrop in the Atlantic which today is home just to seabirds. The St Kilda group lie some 41 miles from the Hebrides - and there is deep water between them.

Continents - are they adrift?

At http://davidpratt.info/sunken.htm there is a provocative article on continental drift which questions some of the assumptions basic to Plate Tectonics theory. We forget that it is still a theory and assume it is a proven scientific concept - as it is consensus science. Read the article and you might be surprised by what is said. For example, what caused Plate Tectonics to be accepted as mainstream science was the discovery in the 1950s and 1960s of a series of magnetic stripes in the rocks on the seabed of the Atlantic Ocean.

Ice Cores

It seems the Vostok ice core extracted from the Antarctic ice sheet goes back around 700,000 years - and even this is a calculation based on a number of variabilities. It came to an end near the rock basement. I can remember reading something similar about a Greenland ice core - so what is actually going on. The Antarctic ice sheet is thought to be immeasurably older - by millions of years. It is thought old ice is squeezed laterally away towards the sea - to melt.

Eocene - tropical jungles thriving in what are now temperate zones

At www.physorg.com/print226319418.html is a report on a paper in the journal Science (June, 2011) that focuses on the Antarctic Circumpolar Current as a cause of the assumed global cooling 38 million years ago that led to the icing over of the southern continent. Up to this point, it seems, tropical jungle thrived in what is now the US Midwest, and Antarctica was temperate - with large numbers of marsupials. Was it still joined to Australia?

Giant fjords beneath Antarctica

Thiss story can be seen at www.sciencedaily.com/releases/2011/06/110601134253.htm and is based on a paper in Nature just out. It is also featured, with comments, at http://wattsupwiththat.com/2011/06/01/radar-mapping-reveals-ancient-anta... which indicates the manner of the research, radar mapping that is able to penetrate thick ice to look at what lies underneath. What they have been looking at is a subglacial basin buried under eastern Antarctica amd this basin, larger than Texas (and therefore larger than Yorkshire) is cut by fjords.

The biosphere ... beginnings

At www.sciencedaily.com/releases/2011/05/110518121227.htm 'Young Graphite in Old Rocks challenges the Earliest signs of Life' ... (the same story can be found at www.geology.com May 24th) and it seems that carbon found within ancient rocks has played a leading role in the development of a time-line for the emergence of biological life on earth. The rocks have been dated millions and even billions of years in the past - but now it has been found graphite (a carbon) dates somewhat younger, even very much younger, in what are some of the oldest rocks on earth in NE Canada.

Beringia

A little geological history of the Bering Straits or Land Bridge is available at ( http://archaeology.about.com/bcthroughbl/qt/beringia.html?nl=1 ). Whenever sea levels in the region dropped by 50 metres below the present position the land surfaced. The dates when this happened have been difficult to establish precisely simply because at the moment the region is submerged. In general terms it is thought Beringia was exposed between 60,000 to 25,000 years ago. During the Late Glacial Maximum, 25,000 to 18,000 years ago, it is thought Beringia was cut off both in the east and in the west.