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作者 Hogarth, Leah Jolynn
書名 Tectonic signatures on active margins
國際標準書號 9781109671599
book jacket
說明 137 p
附註 Source: Dissertation Abstracts International, Volume: 71-04, Section: B, page: 2261
Adviser: Neal W. Driscoll
Thesis (Ph.D.)--University of California, San Diego, 2010
High-resolution Compressed High-Intensity Radar Pulse (CHIRP) surveys offshore of La Jolla in southern California and the Eel River in northern California provide the opportunity to investigate the role of tectonics in the formation of stratigraphic architecture and margin morphology. Both study sites are characterized by shore-parallel tectonic deformation, which is largely observed in the structure of the prominent angular unconformity interpreted as the transgressive surface
Based on stratal geometry and acoustic character, we identify three sedimentary sequences offshore of La Jolla: an acoustically laminated estuarine unit deposited during early transgression, an infilling or "healing-phase" unit formed during the transgression, and an upper transparent unit. The estuarine unit is confined to the canyon edges in what may have been embayments during the last sea-level rise. The healing-phase unit appears to infill rough areas on the transgressive surface that may be related to relict fault structures. The upper transparent unit is largely controlled by long-wavelength tectonic deformation due to the Rose Canyon Fault. This unit is also characterized by a mid-shelf (∼40 m water depth) thickness high, which is likely a result of hydrodynamic forces and sediment grain size
On the Eel margin, we observe three distinct facies: a seaward-thinning unit truncated by the transgressive surface, a healing-phase unit confined to the edges of a broad structural high, and a highly laminated upper unit. The seaward-thinning wedge of sediment below the transgressive surface is marked by a number of channels that we interpret as distributary channels based on their morphology. Regional divergence of the sequence boundary and transgressive surface with up to ∼8 m of sediment preserved across the interfluves suggests the formation of subaerial accommodation during the lowstand. The healing-phase, much like that in southern California, appears to infill rough areas in the transgressive surface. Reflectors within the laminated upper unit exhibit divergence towards the Eel River Syncline, which suggests that deposition in the syncline is syntectonic. The transgressive surface is offset across the Eureka Anticline indicating deformation has occurred since ∼10 ka. The relief observed along the transgressive surface is consistent with deformation rates measured onshore
School code: 0033
Host Item Dissertation Abstracts International 71-04B
主題 Geology
Marine Geology
Alt Author University of California, San Diego. Earth Sciences
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