HR: 1340h
AN: T13D-0496    [Abstracts]
TI: Spectral Analysis and Isostasy of the Alpha-Mendeleev Ridge, Arctic Ocean
AU: * Williams, C C
EM: ftccw@uaf.edu
AF: Geophysical Institute University of Alaska, Fairbanks, 903 Koyukuk Dr., Fairbanks, AK 99775 United States
AU: Coakley, B
T13D-0496 AF: Geophysical Institute University of Alaska, Fairbanks, 903 Koyukuk Dr., Fairbanks, AK 99775 United States
AB: The history of the Mesozoic age Amerasian Basin in the Arctic Ocean is not well understood. Basic geophysical data are sparse due to permanent ice cover. Since the Alpha-Mendeleev Ridge (AMR) crosses the ocean, it is crucial to constrain its origin and evolution in order to better understand how the Amerasian Basin evolved. Anecdotal evidence suggests that the Mendeleev Ridge (MR) might be composed of extended continental crust. If it can be demonstrated that these are distinct structures, formed in different events, then very different tectonic models than are currently popular will be necessary to explain the origin of the basin. For this study, we present a spectral analysis of gravity and bathymetry data over the AMR from two data sources. Spectral techniques provide isostatic information without prior assumptions about compensation. Thus these techniques are appropriate because little is known of the history and current state of isostatic compensation of the AMR. The analysis was done separately using profiles over the AMR from both gridded datasets from the International Bathymetric Chart of the Arctic Ocean (IBCAO) and the Arctic Gravity Project (AGP), and then for individual projected shiptracks collected during an unclassified cruise on the US Navy submarine Cavalla (SCICEX 95). Transfer functions estimated by this method are compared to theoretical isostatic models to constrain how isostatic compensation is achieved for the ridge. In general the profiles from gridded data did not produce stable solutions, however the individual shiptracks did produce well-constrained solutions. Transfer functions found using this method resemble those of locally compensated aseismic oceanic ridges and compare well to theoretical isostatic models. Preliminary results indicate that the transfer function for the MR is best described by local isostasy with an average crustal thickness between 20-30 km. From the results presented we can constrain the theories of origin for the AMR and its place in the Amerasian basin.
DE: 3010 Gravity and isostasy (1218, 1222)
DE: 3255 Spectral analysis (3205, 3280)
DE: 9315 Arctic region (0718, 4207)
SC: Tectonophysics [T]
MN: Fall Meeting 2005