Exploration of a Frontier Region: Statistical Comparison of Detrital Zircon Suites from the Russian Arctic
Elizabeth L. Miller1 and Alex Soloviev2
1Geol. and Environ Sciences, Stanford University, Stanford, CA.
2Alex Soloviev, Geological Institute, Russian Academy of Sciences, Moscow, Russia.
Over 60 sets of detrital zircon data (~ 100 grains/sample) from the Russian and Alaskan sectors of the Arctic are compared and contrasted using relative age probability distribution diagrams, cumulative age probability curves and the Kolmogorov-Smirnov test in order to establish major depositional sequences and their provenance through time. These data help constrain paleogeography, tectonic events and test plate tectonic models. The comparison-based analysis provides a baseline for determining the age, provenance, and tectonic affinity of stratigraphic units dredged or drilled in the offshore. At least four major clastic depositional systems are defined:
1. In the Carboniferous and Permian, a broad carbonate shelf characterized the Barents region of the Russian Arctic between the Caledonides and the nascent Urals. Comparison of detrital zircon suites from Chukotka, Wrangel Island and N. Alaska suggest they formed the seaward portion of the Barents Shelf (with the paleo Pacific) before the Amerasian and Eurasian basins opened. River systems provided detritus to this shelfal region from the Baltic shield, the Caledonides, and sometimes from Neoproterozoic basement that flanked the Baltic shield.
2. Permo-Triassic rifting broke apart the Barents platform. Rift systems and shoulders re-organized river systems. Some transported material from Uralian sources towards the Pacific margin of Arctic Russia. Others re-worked Neoproterozoic and Caledonian material into Triassic shelf basins. Rift basins likely connected to Triassic back-arc basins of the northern Pacific.
3. Late Paleozoic-early Mesozoic siliciclastic strata deposited along the paleo-Pacific margin of Siberia (Verkoyansk) were transported by the “paleo-Lena” transcontinental river system from the actively deforming southern margin of Siberia into shelf to deep water settings. Zircon suites track the depositional ages of host sediments and reflect the tectonic and magmatic history of their source regions.
4. In the Jurassic to earliest Cretaceous, Pacific margin subduction brought changes to the above depositional systems with the collision and accretion of upper Paleozoic to Jurassic arc systems, reversing river systems and providing new orogenic sources that fed foreland basins. This re-organization was fleeting, followed by a profound rifting event that ultimately formed the present Amerasian Basin (mid to Late Cretaceous) and the Eurasian Basin (Tertiary).
AAPG Search and Discover Article #90096©2009 AAPG 3-P Arctic Conference and Exhibition, Moscow, Russia