Focused exhumation in the syntaxis of the western Chugach Mountains and Prince William Sound, Alaska
Jeanette C. Arkle et al., Dept. of Geology, University of Cincinnati, P.O. Box 0013, Cincinnati, Ohio 45221, USA. Posted online 5 April 2013; http://dx.doi.org/10.1130/B30738.1.
The Yakutat microplate is subducting at a shallow angle beneath southern Alaska and in the region of maximum curvature of most of the major mountain belts and faults -- the southern Alaska syntaxis. The shallow subduction is thought to be responsible for most of the deformation in the region, as well as for devastating earthquakes such as the 1964 Good Friday M9.2 megathrust earthquake. Most studies of deformation have concentrated on the inboard deformation areas along the Denali fault in the Alaska Range, or on the more outboard collision-related deformation in the St. Elias orogen. This new study by Jeanette C. Arkle and colleagues focuses on the western Chugach Mountains and Prince William Sound area in between the inboard and outboard regions. They use thermochronologic data to infer recent and relatively rapid rock uplift that is focused in the core syntaxial area and interpret this focused rock uplift as being caused by underplating above the shallow subducting microplate. The increase in underplated material may be the result of influx of material derived from erosion of the St. Elias orogen farther outboard, thus attesting to the causal and temporal linking of these orogenic systems and the positive feedbacks between precipitation, glacial activity, and rock uplift.
Linking offshore stratigraphy to onshore paleotopography: The Late JurassicPaleocene evolution of the south Norwegian margin
Tor O. Smme et al., Statoil, Martin Linges vei 33, 1330 Fornebu, Norway. Pos
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