COMPLETING THE PLATE TECTONIC REVOLUTION: A PROJECT TO RECONSTRUCT PRE-PANGEA SUPERCONTINENTS USING THE LARGE IGNEOUS PROVINCE (LIP) RECORD

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.

Unfortunately, the state of understanding of pre-Pangea reconstructions and their specific paleogeographies is tentative at best. There is good evidence, based on the episodic nature of orogenic belts, that there have been several Precambrian supercontinents: in the late Archean- early Paleoproterozoic (e.g., Kenorland, or perhaps three supercratons, Superia, Sclavia, and Vaalbara), in the late Paleoproterozoic-early Mesoproterozoic (Nuna, aka Columbia), and in the early Neoproterozoic (Rodinia). Beyond these general concepts, the exact reconstructions are poorly constrained.

Because of recent advances in the recovery and U-Pb dating of baddeleyite, we can now for the first time, reliably 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. 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, we can compare and reconstruct the dispersed component pieces into past supercontinents.

Based on this approach, we have organized an Industry-Government-University consortium for a 5 year project to make substantial progress toward producing robust reconstructions of pre-Pangea supercontinents. We have assembled an international team of co-workers to obtain the necessary samples from around the world and we are integrating the complementary expertise from related fields such as paleomagnetism and geochemistry. This project, inspired by basic academic research, is being sponsored by mining and oil companies. See http://www.largeigneousprovinces.org/09jan.html and also the project website, www.supercontinent.org, for more information.