Bathymetry and gravity data from Shatsky Rise, Northwestern Pacific Ocean : implication for the origin and evolution of an oceanic plateau /
Shatsky Rise is located in the northwestern Pacific Ocean and is the oldest extant oceanic plateau formed probably in the Late Jurassic or Early Cretaceous. As with many other oceanic plateaus, the origin of the rise is poorly known. Unlike other oceanic plateaus in the Pacific, Shatsky Rise contain...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1999.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733673211&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Shatsky Rise is located in the northwestern Pacific Ocean and is the oldest extant oceanic plateau formed probably in the Late Jurassic or Early Cretaceous. As with many other oceanic plateaus, the origin of the rise is poorly known. Unlike other oceanic plateaus in the Pacific, Shatsky Rise contains magnetic lineations, key to its tectonic history. Bathymetry and gravity data were analyzed to study the origin of Shatsky Rise. Bathymetry data constrain volcanic morphology of the rise. Gravity data constrain the density structure of the rise. Shatsky Rise consists of three volcanic massifs, small seamounts, and a low relief ridge. Each of the massifs has a domal and more or less symmetrical shape. The volume of the massifs shows a decrease from SW to NE. Also, magnetic lineations indicate an age progression, younger from south to northeast. Volume and age trends imply that Shatsky Rise formed by episodic volcanism. Volcanic massifs have low slopes (<20) similar to flood basalts. Parallelism of mythology and magnetic lineations implies that ridge crests modified the rise flanks. Two basins exist within the crest. One, Helios Basin, is interpreted as an abandoned rift basin. The other, Sliter Basin, seems to be normal lithosphere blanketed by rise sediments. Low relief Papanin Ridge may connect to Hess Rise. The lineation-parallel Ojin Rise Seamounts have different morphology from main massifs and higher slopes (6-8)ĚŠ, implying different origin. Low amplitude free-air anomalies contrast to the large size of Shatsky Rise and indicate that the rise is compensated by Airy isostasy. Low amplitude isostatic gravity anomalies indicate that density anomalies within the rise are few. Ojin Rise Seamounts show the thin elastic plate thickness (5 km) from a flexure model indicating that the seamounts formed near the ridge. The morphology of Shatsky Rise is consistent with the plume-head hypotheses in which TAMU Massif represents plume-head eruption and Papanin Ridge represents the Low output plume-tail. ORI and Shirshov Massifs may be the product of a transition from plume-head to plume-tail. Gravity data are consistent with eruption of all edifices near the spreading ridges, implying the rise history is one of plume ridge interactions. |
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| Item Description: | Vita. "Major Subject: Oceanography". |
| Physical Description: | xvi, 183 leaves : illustrations, maps ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 166-174). |