Rocks, oldest existing

The oldest existing rocks on Earth, from the Isua supracrustal belt of West Greenland, are dated at 3.8 X 10 years (Moorbath et al., 1973) and consist of metamorphosed sediments. It has been suggested that the carbon in the Isua banded iron formation may be photosynthetic in origin (Schidlowski et al., 1979). Whether this remarkable conclusion is substantiated by further work remains to be seen. It is in any case abundantly clear from the available evidence that the conditions of deposition of the oldest known sediments were remarkably like those prevailing during the rest of the Archaean (4.6 — 2.6 X 10 years). Furthermore, with the exception of the appearance... 

Aqueous chemistry is one of the oldest forces of change in the solar system. It started less than 20 million years after the gases of the solar nebula began to coalesce into solid objects.2 Water is also the most abundant volatile molecule in comets. On the earth, the oceans alone contain about 1.4 x 1021 kilograms or 320,000,000 cubic miles of water. Another 0.8 x 1021 kilogram is held within the rocks of the earth s crust, existing in the form of water of hydration. The human... 

One conclusion drawn from radioactive measurements is that the pre-Cambrian history of the earth s crust extends beyond 2,700 million years, The pegmatites that have been found to be this old are located in North America and Australia, and they probably exist oil all the continents. The oldest rocks in the United States that have been measured are on the south rim of the ftridger Mountains near the Wind River Canyon in Wyoming. These ancient pegmatites intrude geologic formations of sedimentary and volcanic rocks that, themselves, are the result of even more ancient processes than those in which they were formed. Thus, a period of the order of 3,000 million years or more is available for geologic processes that have formed the crust seen today. 

SIMS is the oldest of all existing MSI technologies as it was already used in the late 1960s to collect some of the first ion images of monolayers (18). Since then, SIMS has been widely used in material science to study hard surfaces like semiconductors or rocks (19). 

Space and astronomy is the oldest of all sciences. Long before humans understood the composition of rocks and minerals, knew how chemical reactions take place, or even discovered how their own bodies were constructed and operated, they knew of the existence of bodies beyond the Earth s atmosphere other planets, stars, and a variety of strange objects for which they had only simple explanations. The knowledge that early astronomers had of the skies was quite remarkable. They were able to predict the motion of stars, the arrival of seasons, the appearance of eclipses, and other astronomical phenomena with an accuracy that is quite astonishing to modern scientists. 

The oldest rocks on earth have been dated at 3.8 X lO y. The rocks at the earth s surface have been subjected to extensive weathering, so even older rocks may have existed. This age, 3.8 X lO y, thraefore represents the minimum possible age of the earth—the time since the solid crust first formed. Ages of meteorites, assumed to have solidified at the same time as other solid objects in the solar system, including earth, have been determined to be 4.4 X 10 y to 4.6 X 10 y. It is now believed from this and other evidence that the age of the earth is 4.6 X 10 y. 

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