Seismic reflection data and interpretations, integrated with regional geological constraints, provide the basis for a new crustal transect (the Circum-Arctic Lithosphere Evolution (CALE) Transect C) linking the Arctic Ocean to the Pacific margin along two paths that span 5100 km from the Lomonosov Ridge (near the North Pole), across the Amerasia Basin, Chukchi Sea and Bering Sea, and ending at the subducting: Pacific plate margin in the Aleutian Islands. Shown are the transects on a geologic map of the Arctic.
With the advent of U-Pb dating of detrital zircon suites from sandstones with the LA-ICP-MS method it has become routine to collect large and statistically meaningful data sets on the provenance of clastic successions. In remote regions such as the Arctic, where so much is still to be discovered, this technique has been used with great success to determine the first order provenance of sandstones and to match sedimentary successions now separated by rifting. Our work has been funded by a variety of sources including NSF Award 09-542, the American Chemical Society PRF Award 45432-AC8, Exxon-Mobil, Shell International and British Petroleum.
Our studies in the Bering Strait region began with the desire to further understand and compare the geotectonic evolution of Alaska with that of North-East Russia and the Arctic. They grew into a project that provides a better understanding of the links between processes in the mantle and crust and the importance of mantle-derived magmatism and heating in lithospheric extension. Funded by NSF EAR-9018922, NSF Continental Dynamics EAR-93-17087 and a variety of other sources. Illustration shows main granitic batholiths (red) and volcanic rocks (grey with white chicken tracks)
Mesozoic intrusive and volcanic rocks constitute major components of the geology of the Russian Far East. They have been mapped and studied in detail because of their associated mineralization, especially their gold deposits.
Modern U-Pb geochronology of zircons from granitic rocks is beginning to unravel the relative age relations between the various regions and belts of magmatism in the Russian Far East. Older K-Ar dating of these rocks had such a huge spread of ages that it was not possible to discern the space-time progression of magmatism that is now much better known across this region.
Most of the studies and data discussed here were carried out in collaboration with J.Wooden of the U.S. Geological Survey at the joint USGS-Stanford SHRIMP-RG facility.
The history of magmatism in the Russian Far East is intimately related to Pacific margin tectonics as well as to the opening history of the Arctic Ocean Basins. The exact timing of magmatism thus places important contraints on these plate motions through time.
The Amerasian Basin of the Arctic Ocean remains one of the last plate tectonic puzzles on Earth. It's ocean floor has never been drilled scientifically and its origin is very controversial. We are integrating our work across Arctic Russia with new data being collected within the Amerasia Basin in order to place kinematic and timing constraints on the plate tectonic rift history of the Arctic Ocean.
A broad zone of fault-related deformation, called the Schist Belt, stretches E-W for more than 600 km along the southern side of the Brooks Range in northern Alaska. This fault zone played a fundamental role in the formation of flanking sedimentary basins, the Yukon-Koyukuk Basin to the south and the Colville Basin to the north of the Brooks Range. It is also the main structure separating southern Alaska, with a geologic history tied to the Pacific plate margin, from northern Alaska, whose history is tied to plate tectonics in the Arctic Ocean. Despite its impressive physical extent, questions about its exact age and hypotheses about why and how it developed are debated. This project is studying the geology and deformation history of this fault zone, sharing logistics with an international Swedish project whose goals are to better understand the geology of the Arctic region.
The Chukchi Borderland is an unusually shaped rectangular region that juts northward into the deep Arctic Ocean from Arctic Alaska's Beaufort and Chukchi Shelf (Figs 1, 2). The borderland is transected by north-south trending normal faults giving it a ridge-like nature with flat plateau-like crests (Fig. 2).