Collaborative Research: Mining SCICEX Geophysical Data in the Arctic Ocean to Constrain the Structure and Geologic Development of the Amerasian Basin

University Of Alaska Fairbanks Campus, Fairbanks AK

Investigators

Abstract

Abstract OPP-0240964 Cochran OPP-0241004 Coakley OPP-0241188 Edwards This is a collaborative proposal by Principal Investigators at Lamont Doherty Earth Observatory and the Universities of Hawaii and Alaska. Between 1995 and 1999, the U.S. Navy carried out five nuclear submarine cruises to the Arctic Ocean for civilian scientific research through the SCICEX (SCience ICe EXercise) program. The Seafloor Characterization and Mapping Pods' (SCAMP)instrument package, an integrated geophysical survey system providing gravity, swath bathymetry and sidescan, and chirp sub-bottom profiler data was installed on the submarine for the 1998 and 1999 cruises. During those two cruises, SCAMP geophysical data were acquired over the major Arctic Ocean floor features. These data were used to determine the morphology, structure and tectonics of the Gakkel Ridge which occupies a singularly important position as the slowest spreading portion of the global mid-ocean ridge system, and to test the hypothesis of the existence of a Pleistocene Arctic ice sheet by imaging shallow portions of the Arctic Ocean for glaciogenic features. The purpose of this project is to allow continued mining of this unique and rich data set and to address important questions related to the origin, structure and development of the Amerasian Basin. The primary foci of the proposed work will be the Lomonosov Ridge, a sliver of continental crust extending across the Arctic Ocean separating the Mesozoic Amerasian Basin from the Tertiary Eurasian Basin, and the Chukchi Borderland, a high-standing area of extended continental crust jutting into the Canada Basin. Geophysical studies of the SCICEX data from the Amerasian Basin emphasizing those features allow investigation of a very simple, but unanswered and extremely fundamental question: How did the Amerasian Basin come into being? The origin and tectonic development of the basin has been very controversial. Published data from the basin is inconclusive and can be used to support radically different models. Principal Investigators will determine the structure and the type of rifting and distinguish among the different models. The Chukchi Borderland is a block of continental crust protruding into the Amerasian Basin. Different models for the development of the Amerasian Basin propose different modes of formation for the northern and eastern (Northwind Escarpment) margin of the Borderland. SCAMP data will provide the necessary data to determine the structure of the margin and the form of rifting and to allow further tests for the models for the origin of the basin.