Detrital Zircon Geochronology and Plate Tectonic Reconstruction of the Arctic
Elizabeth L. Miller
Geol. and Environ Sciences, Stanford University, Palo Alto, CA.
Detrital zircon geochronology is a powerful means of establishing paleogeographic ties between regions translated or rifted apart as a consequence of plate motions. The Arctic represents a series of relatively small ocean basins formed in the Cretaceous and Cenozoic that rift apart a series of longer established, mostly shelf and shelf basin systems and orogenic belts. This method is especially valuable in the Arctic as it can be used to establish changing clastic source regions through time in sedimentary sequences prior to rifting and can provide fairly specific tie-points between the various components of this prior paleogeography.
We have collected and compiled detrital zircon geochronologic data sets from various parts of the Arctic and from rocks that span the Paleozoic and Mesozoic. The results of these studies provide remarkable insight and tie points between the Eurasian and Pacific sides of the present Arctic region and suggest that these two parts of the Arctic were once much closer together than previously imagined.
Increasingly robust detrital zircon data sets suggest that Wrangel Island, Chukotka and N. Alaska (the Arctic Alaska-Chukotka microplate) restore against the Lomonosov Ridge upon closure of the Amerasia Basin and to the edge of the Barents Shelf after closing the Eurasia Basin. Detrital zircon data from younger (Jurassic and Cretaceous) strata provide additional evidence that the original Barents Shelf continental margin was much closer to the paleo-Pacific margin than previously thought. This proximity brings up the likely possibility that Pacific subduction-driven tectonics played a more fundamental role in the evolution of the Arctic Amerasia Basin than previously thought.
AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia