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Australia: The Land Where Time Began |
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Northwestern Australia and East Africa – A Deglaciation Event in the
Early Permian between these 2 Landmasses
Along the entire length of the Tethyan margin of Gondwana the base of
the Gondwana megasequence is formed by glacigene deposits from the late
Palaeozoic. The prevailing climate largely controlled the lithology of
the deposits in these sequences and the climate influence was also
imposed on early diagenesis*. A change from a mineralogically immature
composition (arkosic chloritic) of the periglacial sediments to a
mature, kaolinite pyrite quartz dominated lithofacies of the periglacial
deposits reflects the
change from the cold glacial climate to a postglacial environment that
was cool temperate. The appearance of black, kaolinitic lutites, that
usually have high organic carbon content, is a typical feature of the
latter period. In this paper only a few examples of typical deglaciation
sequences, of the many known occurrences, are discussed, including
Tanzania, Southern Oman, the Lesser Himalaya, northwestern Australia and
southwest China. These deglaciation sequences have been shown by
microflora and fauna that all these deglaciation sequences are from the
Late Asselian to Early Sakmarian age indicates that along the Tethyan
margin of Gondwana deglaciation was a synchronous event, within the
limit of dating methods. In the Late Sakmarian/Early Artinskian a peak
in sea level was experienced in all but 1 of the sections that have been
described here, which supports this statement. The sudden increase of
bioproduction that was stimulated by higher temperatures and a high
atmospheric carbon dioxide concentration caused the high level of
organic matter content in the deglaciation deposits. The dominance of
euxinic conditions during this period was a high organic material,
combined with basin geometries that were overdeepened. According to
Wopfner the rapid, synchronous amelioration of climate cannot be
explained by the shifting of pole positions, rather, only by global
warming that was rapid and sustained.
*https://en.wikipedia.org/wiki/Diagenesis
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Author: M.H.Monroe Email: admin@austhrutime.com Sources & Further reading |