Don, Perhaps you are close to being right.
According to ...Scientific American it now seems that we have evidence of an Earth land mass dating back to at least 4.4 bya. The oldest intact rock is found in Canada and dates back to 4 bya; however, zircon crystals found in Western Australia date back to 4.4 bya. Because these crystals have a high oxygen isotope level, only found in cooler areas than magma, it is thought they that they were formed under liquid water and low temperature conditions on the surface of the Earth. This pushes the age of Earth's known initial landmass back by "at least 400 million years earlier than the oldest known existing sedimentary rocks, those at Isua, Greenland [3.8 bya]". So the Earth may have cooled in merely 100 million years and formed a landmass or landmasses as early as 4.4 bya. "A Cool Early Earth," by Jogn W. Valley, Scientific American, Oct. 2005, pp. 59-63. Another post I found cites this information: http://www.sciforums.com/showthread.php?t=49695 Most scientist agree that the Barberton Greenstone Belt in eastern Africa is the oldest mountain range on Earth (3.5 billion years old), and it is said that it is possible to deduce the entire geological history of the Earth by examining these uprising mountains in this ancient sea floor area. The Guiana Highlands in South America are thought to be the earth's oldest surface (2 billion years old): it includes a large mountain plateau. Then there is the Medicine Mountain on Wyoming were they have dated rocks to 2-3 billion years ago. However, on top of all this we have the 3.8 billion year old 25 mile long band of zircon crystal rocks embedded in the Isua crust in Greenland! http://findarticles.com/p/articles/mi_m1134/is_4_113/ai_n6026419/ A lot of people in the U.S. think that the Appalachians were among the oldest mountains formed. Although they are very impressive, stretching from the Eastern U.S. to Canada, Labrador, Scotland and down to Morocco, they were formed only about 680 mya during the formation of Pangaea. But we now know that Pannotia preceded Pangea and another supercontinent called Rodinia formed 1,100 mya. Ed Frank "The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science." - Albert Einstein --~--~---------~--~----~------------~-------~--~----~ Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected] -~----------~----~----~----~------~----~------~--~---
