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Thread: Development of Oxygen Atmosphere

  1. #1 Development of Oxygen Atmosphere 
    Universal Mind John Galt's Avatar
    Join Date
    Jul 2005
    Part of the explanation for the Cambrian explosion of complex life forms relates to increase in oxygen in the atmosphere. In earlier times, despite a couple of billion years of photosynthesis, the amount of oxygen in the atmosphere is thought to have been to low for complex metazoans to develop.
    In an interesting paper in Science, pre-published in Science Express, it is suggested that the oxygen was allowed to build up only after carbon was sequestered in clays.

    Late Precambrian Oxygenation; Inception of the Clay Mineral Factory
    Martin Kennedy et al
    An enigmatic stepwise increase in oxygen in the late Precambrian is widely considered a prerequisite for the expansion of animal life. Accumulation of oxygen requires organic matter burial in sediments, which is largely controlled by the sheltering or preservation by detrital clay minerals in modern marine continental margin depocenters. Here we show mineralogical and geochemical evidence for an increase in clay mineral deposition in the Neoproterozoic that immediately predated the first metazoans. Today most clay minerals originate in biologically active soils, so initial expansion of a primitive land biota would greatly enhance production of pedogenic clay minerals (the "clay mineral factory"), leading to increased marine burial of organic carbon via mineral surface preservation.

    If this hypothesis is borne out by further investigation it has important implications for the development of extraterrestrial intelligence. Any one interested in discussing?

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