Complex life forms on land in the pre-Cambrian era?
|April 26, 2014||Posted by News under Cambrian explosion, Intelligent Design, News|
Yup, says Paul Knauth.
According to prevailing wisdom, the continents were lifeless, irradiated rock shelves until after the occurrence known as the Cambrian explosion in the seas 540 million years ago, when the precursors to rooting plants and animals burst forth from the ocean to colonize the land. Knauth has long led the charge to challenge that narrative, which is biased by the fossil record, he said. Marine fossils are protected by layers of marine sediment and the quietude of ocean deeps. Land fossils are much more likely to have been pulverized by changing climates and erosion long before paleontologists could have chanced upon them. The fossil record, therefore, is heavily weighted toward the seas, making it appear that they were the cradle of life.
According to Knauth, the surviving land-based fossils are most likely to be tiny and hidden in “geological time capsules,” such as the Death Valley cave, which has withstood volcanoes, glaciers and the clashing of continental plates. During the last 10,000 years, the cave was sliced open by rainwaters flushing the surrounding landscape, a 750- to 800-million-year-old geological formation called the Beck Spring Dolomite. In the early 1990s, Knauth analyzed the geochemistry of the surface of this 1,000-foot layer of dolomite. His results showed that the region seethed with mats of photosynthesizing, unicellular life forms long before the Cambrian explosion.
Nearly 30 years later, the field is finally catching up with him. During the last half decade, a number of researchers have reported an abundance of geochemical and microfossil evidence that life inhabited the continents as far back as 2.2 billion years ago.
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