LYCOS RETRIEVER 
Precambrian
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The six-week Precambrian field camp is a 6 semester credit class listed as GEOL4500 (Sec. 2) in the UMD course catalog. Students will be required to have taken a semester of petrology and structural geology.
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One of the great stories of the Precambrian is the evolution of an oxygen atmosphere. Oxygen in the atmosphere not only resulted in one of the greatest ecological crises in Earth's history, it ... was a necessary precursor to the evolution of multicellular animals (metazoans). Of course an oxygen atmosphere is a direct consequence of living organisms - it could not exist with just geologic/atmospheric origins. A direct result of the production of oxygen is the conversion of iron pyrite (FeS2) and oxygen (O2) into hematite (Fe2O3) and gypsum (CaSO4.2H2O).
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Although the Precambrian contains some seven-eighths of Earth's history, its fossil record is poor, with the majority of fossils being the stromatolites that are often heavily metamorphosed or deeply buried. However, preserved cells have been discovered at selective sites, such as the 2.0 Ba Gunflint Formation. The earliest life forms were prokaryotes (eubacteria or archaea) that evolved in the seas, possibly as early as 3.8 Ba. The first were probably chemotrophs existing in an anoxic world and producing H2S or CO2, which were followed by photosynthetic cyanobacteria before the end of the Archaean at 2.5 Ba. When the Eukaryotes (single-celled organisms with a nucleus) evolved through Endosymbiosis is disputed, with claims as early as 3.4 Ba, but with less equivocal fossils dating from 1.8 to .8 Ba. With the eukaryotes comes sexual reproduction, enabling genetic diversity and the concomitant ability to adapt to and survive environmental changes.
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Within the global uniformitarian stratigraphic timescale, plant fossils have been found in Precambrian strata dated to approximately 3.5 billion years in age. Evolutionists have not successfully explained when or how life formed to produce these ancient and wide-spread plant fossils. Young-earth creationists have ... investigated Precambrian plant fossils, focusing primarily on Precambrian rocks found in the Grand Canyon. Controversy has developed around the plant fossil content of the 1.25 billion year old Hakatai Shale. Several studies suggest that modern and ancient fossilized plant material might be present within the shale. Other Precambrian stratigraphic units in the Grand Canyon contain plant fossils.
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In southwestern Kansas the Precambrian surface is largely unweathered. Quartzite outliers occur along the Central Kansas uplift in northeastern Barton County (Walters, 1946) and in southeastern Kansas (Ireland, 1955). The configuration of the Precambrian surface is reflected by the structural features depicted in Figure 6. Merriam (1963) reported that all major positive features on the Precambrian surface have a southerly plunge, and in general the Precambrian surface slopes southward.
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The Precambrian basement of England and Wales is exposed within a number of inliers, which are regarded as ‘windows’ through the cover strata. The rocks that are revealed are of considerable geological diversity. The Precambrian outcrops are sparsely distributed and generally occupy relatively small areas of southern Britain.
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Precambrian