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| Detailed Reference Information |
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Sager, W.W. and Pringle, M.S. (1987). Paleomagnetic constraints on the origin and evolution of the Musicians and South Hawaiian seamounts, Central Pacific Ocean. In: Seamounts, Islands and Atolls, Geophysical Monograph Series 43. Keating, B.H., Fryer, P., Batiza, R. and Boehlert, G.W. (Editors), American Geophysical Union, Washington, D.C.. 43: 133-162. |
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Twenty-two new paleomagnetic poles, 24 paleoinclinations, and 14 new radiometric ages have been determined for seamounts and ridges in the Musicians Seamounts and the South Hawaiian seamounts. The geologic and tectonic implications of these data are presented in this report. Paleolatitudes show that the seamounts were formed astride the equator and are consistent with coeval volcanism over a range of 10 degrees -20 degrees of latitude. These data show no clear evidence for the origin of any of the seamounts at fixed-latitude hotspots; however, a progression of ages in the NW-SE trending chain in the Musicians implies a hotspot formation. Two mean paleomagnetic poles defining the Pacific plate Cretaceous apparent polar wander path at 80 and 87 Ma of age were calculated. Age estimates were made for undated seamounts by comparing their paleomagnetic poles to the updated apparent polar wander path. The results imply volcanism over a period greater than 20 Ma, from before 90 Ma to after 70 Ma, in both the Musicians and South Hawaiian seamounts. The similarity of ages of many edifices in both provinces implies that they may have been generated by the same mechanism. The paleomagnetic results from several seamounts in each of the two provinces are interpreted to indicate a possible 15 degrees -26 degrees counterclockwise rotation of two small crustal blocks. A tectonic model is proposed to explain the location and timing of the formation of seamounts in the region using a hotspot to create some of the Musicians Seamounts and tectonic deformation caused by a salient of Farallon plate, trapped between the Murray and Molokai transform faults during a change in spreading direction, to account for the remainder. |
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Keywords
absolute age; Ar/Ar; Central Pacific; Cretaceous; dates; dredged, samples; geochronology; igneous rocks; magnetic inclination;, Mesozoic; Musicians Seamounts; ocean floors; oceanography; Pacific, Ocean; paleolatitude; paleomagnetism; plate tectonics; pole, positions; seamounts; South Hawaiian Seamounts; volcanic rocks, 07 Oceanography; 18 Solid-earth geophysics; 03 Geochronology |
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