interbedded lithologies, and (3) proximity to nearshore carbonates supplying abundant fine-grained detrital carbonate. These combined conditions were best met along flooded, subtropical continental shelves or epeiric seas during My-scale (3rd-order) sea-conditions and over time periods from the Camb...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.490.6389 http://epswww.unm.edu/facstaff/dolomite/pdf/4.pdf |
| Summary: | interbedded lithologies, and (3) proximity to nearshore carbonates supplying abundant fine-grained detrital carbonate. These combined conditions were best met along flooded, subtropical continental shelves or epeiric seas during My-scale (3rd-order) sea-conditions and over time periods from the Cambrian to the Quaternary. Given this, it is difficult to invoke models of internally driven thermohaline oceanic oscillations or continental ice sheet instabilities to explain their origin. Instead, we suggest that Palaeogeography, Palaeoclimatology, Palaeoecology 243 (2007) 348–372 www.elsevier.com/locate/palaeolevel rises. The rhythmic alternation between carbonate-rich and carbonate-poor layers is interpreted to represent millennial-scale paleoclimatic changes related to: (1) wet/dry climate cycles which influenced the amount of continent-derived eolian and/or fluvial sediment input, (2) variations in offshore transport (via storm-generated or density currents) of nearshore-derived terrigenous or carbonate sediments, and/or (3) changes in wind-driven upwelling and availability of recycled biogenic silica. The various rhythmite successions accumulated under dramatically different paleoenvironment and paleogeographic conditions including active to passive tectonic settings, equatorial to subtropical latitudes, long-term icehouse through greenhouse climatic conditions, calcite versus aragonitic seas, variable atmospheric CO2 concentrations, before and after land plant and animal evolution, and across widely varying ocean basin configurations. If our short-term paleoclimatic interpretations for the rhythmites are correct, then it is apparent that millennial-scale climate changes occurred over a very wide spectrum of paleoceanographic, paleogeographic, paleoclimatic, tectonic, and biologicMillennial-scale paleoclimate cycles recorded in widespread Palaeozoic deeper water rhythmites of North America |
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