Space/Science — HabitableZone

Space/Science » in reply to Phoenix Mission Media Telecon Scheduled for June 20 at 10 a.m. PDT (1 p.m. EDT)

If Earth had liquid water and continents 4.3 billion years ago...
Socrates II — (archived)

... does this also apply to Mars?

Ion Microprobe Technology Reveals Earth was Habitable 4.3 Billion Years Ago

A team of scientists led by University of Wisconsin-Madison geologists Takayuki Ushikubo, Valley and Noriko Kita have completed an analysis of ancient minerals called zircons which shows liquid water existed at least 4.3 billion years ago and that heavy weathering by an acrid climate possibly destroyed the surface of the Earth's earliest continents when the planet was a mere 150 million years old.

Zircons, the oldest known materials on Earth, offer a window in time back as far as 4.4 billion years ago. Because these crystals are exceptionally resistant to chemical changes, they have become the gold standard for determining the age of ancient rocks, says UW-Madison geologist John Valley.

Valley previously used these tiny mineral grains — smaller than a speck of sand — to show that rocky continents and liquid water formed on the Earth much earlier than previously thought, about 4.2 billion years ago.

Ushikubo, the first author on the new study, says that atmospheric weathering could provide an answer to a long-standing question in geology: why no rock samples have ever been found dating back to the first 500 million years after the Earth formed.

Full article here:

http://www.dailygalaxy.com/my_weblog/2008/06/ion-microprobe.html

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