Large Igneous Provinces used for Plate Reconstructions
Thursday, 22. October 2009, 08:53:01
Palaegeography is mainly a question of Where was What When. As to the “When”, dating of rocks is of course extremely important. Because of recent advances in the recovery and U-Pb dating (uranium-lead dating) of baddeleyite (a rare zirconium oxide mineral) it is now possible to obtain precise ages for the vast majority of the short duration, huge volume, igneous events, known as Large Igneous Provinces (LIPs) that are widespread on all the ~50 main possible 'puzzle pieces' of the Earth's past plates.
Deccan Traps and Siberian Traps are famous examples of such LIPs, because of their possible role in mass extinctions.
Paleocontinental reconstructions are critical to providing a tectonic context for major ore deposits. They are also important to understanding the full context of sedimentary basins. More broadly, robust paleocontinental reconstructions and the recognition of supercontinents through time are essential for inter-block tracing of all geological and structural features of the lithosphere, including their deep mantle roots, and for providing a paleogeographic framework for assessing Earth’s geodynamic evolution and climatic variations through time.
Precisely dated units can be assembled into a LIP 'barcode' (like a supermarket barcode) that characterizes each 'puzzle piece'. By matching these 'barcodes' and using LIP units (particularly their dyke swarms) as piercing points, it is possible to compare and reconstruct the dispersed component pieces into past supercontinents.
Global barcode of LIPs through time. Abbreviations: NA, North America; SA, South America; EU, Europe; AF, Africa; AS, Asia; Au, Australia; PA, Pacific Ocean. Modified after Ernst et al. (2005).
Deccan Traps and Siberian Traps are famous examples of such LIPs, because of their possible role in mass extinctions. Paleocontinental reconstructions are critical to providing a tectonic context for major ore deposits. They are also important to understanding the full context of sedimentary basins. More broadly, robust paleocontinental reconstructions and the recognition of supercontinents through time are essential for inter-block tracing of all geological and structural features of the lithosphere, including their deep mantle roots, and for providing a paleogeographic framework for assessing Earth’s geodynamic evolution and climatic variations through time.
Precisely dated units can be assembled into a LIP 'barcode' (like a supermarket barcode) that characterizes each 'puzzle piece'. By matching these 'barcodes' and using LIP units (particularly their dyke swarms) as piercing points, it is possible to compare and reconstruct the dispersed component pieces into past supercontinents.
Global barcode of LIPs through time. Abbreviations: NA, North America; SA, South America; EU, Europe; AF, Africa; AS, Asia; Au, Australia; PA, Pacific Ocean. Modified after Ernst et al. (2005).
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http://gsa.confex.com/gsa/2009AM/finalprogram/abstract_160852.htm
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http://www.largeigneousprovinces.org/09jan.html
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http://www.supercontinent.org/
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http://www.largeigneousprovinces.org/
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