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The ancient sea floor was discovered in southwest Greenland A sliver of four-billion-year-old sea floor has offered a glimpse into the inner workings of an adolescent Earth.The baked and twisted rocks, now part of Greenland, show the earliest evidence of plate tectonics, colossal movements of the planet's outer shell. Until now, researchers were unable to say when the process, which explains how oceans and continents form, began. The unique find, described in the journal Science, shows the movements started soon after the planet formed. "Since the plate tectonic paradigm is the framework in which we interpret all modern-day geology,...

The rise of the Appalachian Mountains seems to have triggered an ice age 450 million years ago by sucking CO2 from the atmosphere. Researchers report evidence that minerals from the mountain range washed into the oceans just before the cold snap, carrying atmospheric carbon dioxide with them. The result clarifies a long standing paradox in the historical relationship between CO2 and climate, experts say. At the start of the so-called Ordovician ice age, about 450 million years ago, the planet went from a state of greenhouse warmth to one of glacial cold, culminating in mass extinctions of ocean life. This...

Bacteria froze the Earth, researchers say By Michael Kanellos http://marketwatch-cnet.com.com, marketwatch-cnet.com.com/Bacteria+froze+the+Earth%2C+researchers+say/2100-7337_3-5815965.html Story last modified Tue Aug 02 17:15:00 PDT 2005 Humans apparently aren't the first species to change the climate of the planet. Bacteria living 2.3 billion years ago could have plunged the planet into deep freeze, researchers at the California Institute of Technology claim in a new report. Several graduate students, along with supervising professor Joe Kirschvink, have released a paper presenting their explanation of what caused "Snowball Earth," a periodic deep freeze of Earth's atmosphere that has been theorized for years. The Caltech team argues that 2.3 billion...

Geoscientists in Scotland say they have evidence to disprove the controversial "Snowball Earth" theory - the idea that the planet was completely encased in ice just over 600 million years ago.We are claiming that in reality there was not a totally frozen snowball Earth and that even during the coldest conditions large regions remained ice-free -- Dr Dan CondonThe team, from the University of St Andrews, has published its findings in the scientific journal Geology, after studying rocks in the west of Scotland, Ireland, Namibia and California. Drs Dan Condon, Tony Prave and Doug Benn say they have found evidence...

A sudden and extreme case of runaway global warming 635 million years ago was caused by an abrupt release of methane, a powerful greenhouse gas, scientists said today. The methane seeped from ice sheets that covered much of the planet toward the end of a frigid era called Snowball Earth. The gas escaped gradually at first and then very quickly from clathrates, or methane ice that forms and stabilizes beneath water ice sheets. As the water ice melted, pressure was relieved on the clathrates and they began to de-gas. The transition represents one of the earliest known cases of what...

Source: University of Chicago Date: February 5, 2007 Ancient Rocks Show How Young Earth Avoided Becoming Giant Snowball Science Daily — A greenhouse gas that has become the bane of modern society may have saved Earth from completely freezing over early in the planet's history, according to the first detailed laboratory analysis of the world's oldest sedimentary rocks. A rock from a banded iron formation in northern Quebec, Canada. The bands vary in thickness from approximately 10 microns (less than the width of a human hair), to 10 meters (30 feet). This sample is measures a few inches across. At...

American boffins say they have discovered evidence that almost the entire world was covered in sea ice and glaciers at certain points in the remote past, during so-called "snowball Earth" periods where the polar ice sheets met at the Equator. It were grim in the old days. Geologists probing conditions seen in the ancient world have long considered that there was a cold spell known as the Sturtian Glaciation about 716 million years ago. However there has been disagreement in boffinry circles as to just how severe this glaciation was. Now, researchers from Harvard uni in the States, funded by...

A 250-million-year shutdown of volcanic activity which is thought to have occurred early in Earth's history may be what turned the planet into a glacier-covered snowball. It could also have helped give rise to our oxygen-rich atmosphere. Previous studies have noted that very little volcanic material has been dated to between 2.45 and 2.2 billion years ago, but it was widely assumed the gap would vanish as more samples were dated. Now an analysis of thousands of zircon minerals collected from all seven continents indicates that the gap may be real after all. Zircons provide a record of past volcanic...

Enlarge ImageMolecular fingerprints. Sedimentary rock formations in Oman, like this one, contain chemical evidence of the planet's first animals, which appeared at least 635 million years ago. Credit: David Fike, Nature Where did all the animals come from? The fossil record is virtually animal-free up until the Cambrian Explosion 540 million years ago, and then--boom--thousands of critters of all shapes and sizes show up. The mystery has plagued scientists for more than a century and a half, beginning with Charles Darwin. Now, with a brilliant bit of detective work, researchers have located our missing ancestors. The problem with the...