Paleontology

Identification of the oldest preserved pieces of Earth's crust in southern Greenland has provided evidence of active plate tectonics as early as 3.8 billion years ago, according to a report by an international team of geoscientists in the March 23 edition of Science magazine.

The finding pushes back the date of continent-forming processes previously determined as 2.5 billion years ago to a much earlier era considerably closer to Earth's formation some 4.5 billion years ago. Geochemical analysis of rocks has previously suggested an earlier date for plate tectonics, but this is the first study to find physical evidence of tectonics among Earth's oldest known rock structures, according to Hubert Staudigel of Scripps Institution of Oceanography at UC San Diego.

An international team of American and Chinese paleontologists has discovered a new species of mammal that lived 125 million years ago during the Mesozoic Era, in what is now the Hebei Province in China. The new mammal, documented in the March 15 issue of Nature, provides first-hand evidence of early evolution of the mammalian middle ear--one of the most important features for all modern mammals. 

Named Yanoconodon allini after the Yan Mountains in Hebei, the fossil was unearthed in the fossil-rich beds of the Yixian Formation and is the first Mesozoic mammal recovered from Hebei. The fossil site is about 300 kilometers outside of Beijing.

Snail-racing is an action-packed spectator sport compared to watching the drift of Earth’s continents, which usually move just a few centimetres a year – about as fast as fingernails grow. But occasionally events quicken dramatically, and become interesting enough for a "desk-bound geophysicist" like Dr Tim Wright to pack his bags and go camel-trekking across a desert.

A wedge of sediment, pushed up by glacial movement, may be a buffer against moderate sea level rise, pointing to ocean temperature rise as the key factor in glacial retreat, according to two papers published today (March 1) in Science Express.

"Sediment beneath ice shelves helps stabilize ice sheets against retreat in response to rise in relative sea level of at least several meters," says Richard Alley, the Evan Pugh professor of geosciences, Penn State.

Dr Gavin Prideaux, paleontologist for Western Australian Museum and Flinders University, publishes an article in international journal Geology's January 2007 edition that is certain to fuel what has become one of palaeontology's longest-running and contentious debates.
 
The latest study is unique in providing a long-term perspective on the responses of the megafauna in the Naracoorte Caves region of south-eastern Australia to cyclical swings in Ice Age climates.
 
Australia lost 90% of its large fauna, including rhino-sized marsupials, 3-metre tall kangaroos and giant goannas within 20 thousand years of human arrival.