December 2005

You are currently browsing the monthly archive for December 2005.

Volcanic eruptionNew research to be published in the journal of Geology sheds more light on what was responsible the Permian Extinction, the largest extinction in Earth’s history that happened 250 million years ago. Poisonous volcanic gases that possibly originated from the eruption of the Siberian Traps killed plant life, as well as destroyed the ozone layer.

However, analysis of a unique set of molecules found in rocks taken from the Dolomites in Italy has enabled scientists to build up a picture of what actually happened. The molecules are the remains of polysaccharides, large sugar-based structures common in plants and soil, and they tell the story of the extinction.

The molecules date from the same time as a major volcanic eruption that caused the greatest ever outpouring of basalt lava over vast swathes of land in present day Siberia.

The researchers believe that the volcanic gases from the eruption, which would have depleted earth’s protective ozone layer and acidified the land and sea, killed rooted vegetation. This meant that soil was no longer retained and it washed into the surrounding oceans.

The chemistry of the rocks reveals that although the sugar molecules were found in marine sediments, they derived from land, supporting the theory that massive soil erosion caused them to end up in the sea.

Sphere: Related Content

Related Stories

Human Footprints in MexicoWe’ve previously covered this subject. In July, human footprints in 40,000 year old ash beds had allegedly been found in Mexico. That finding alone has significant implications on when humans first arrived into the Americas.

Now a new team of researchers have been using different dating techniques, such as paleomagnetism and argon-argon, on these ash deposits. The results of their findings? The ash beds are 1.3 million years old. If this is an accurate date (and assuming the footprints aren’t a hoax, or something else entirely), this completely blows away various theories about the speed of human radiation out of Africa.

“If these really are footprints, and they were made 1.3 million years ago, that would be absolutely revolutionary,” said Paul Renne, a geologist at the University of California, Berkeley who was involved in the new dating.

Humans are not thought to have even been around 1.3 million years ago. According to most scientific estimates, modern humans didn’t begin appearing in Africa until about 200,000 years ago. If the markings really are footprints, then it would mean one of two things: either humans appeared much earlier than previously thought or the footprints were made by an early ancestor of humans like homo erectus.

Renne thinks both possibilities are extremely unlikely. So where does that leave things?

Man, cow or machine

Sphere: Related Content

Related Stories

Newer entries »