Resolving the Late Paleozoic Ice Age in Time and Space
Stratigraphic record and facies associations of the late Paleozoic ice age in eastern Australia (New South Wales and Queensland)
Published:January 01, 2008
Christopher R Fielding, Tracy D Frank, Lauren P Birgenheier, Michael C Rygel, Andrew T Jones, John Roberts, 2008. "Stratigraphic record and facies associations of the late Paleozoic ice age in eastern Australia (New South Wales and Queensland)", Resolving the Late Paleozoic Ice Age in Time and Space, Christopher R. Fielding, Tracy D. Frank, John L. Isbell
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Stratigraphic and sedimentological data from New South Wales and Queensland, eastern Australia, indicate that the late Paleozoic ice age consisted of at least eight discrete glacial intervals (each 1–8 m.y. in duration) separated by nonglacial intervals of comparable duration. These events spanned an interval from the mid-Carboniferous (ca. 327 Ma) to the early Late Permian (ca. 260 Ma), and they illustrate a pattern of increasing climatic austerity and increasingly widespread glacial ice from initial onset until an acme in the Early Permian, followed by an opposite trend toward the final demise of glaciation in the Late Permian.
Glacial facies are composed of diamictites, interbedded diamictites, conglomerates and sandstones, rhythmites, laminated mudrocks with dispersed outsize gravel, glendonites, clastic intrusions, faceted, striated, and bullet-shaped clasts, and rare, well-sorted siltstones interpreted as windblown loessites. Carboniferous glacial intervals are predominantly of continental origin and were deposited in an array of mainly glaciofluvial and glaciolacustrine environments. Permian glacial facies, by contrast, were formed mainly in glaciomarine environments. Cyclical vertical stacking patterns occur on a variety of scales, suggesting glacial-interglacial and longer-term fluctuations in climatic conditions.