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" Sediment Movement and Basin Evolution and Fill in a Shale-cored Deepwater Fold and Thrust Belt, NW Borneo Malaysia "
Kobayashi, Hirofumi
Wood, Lesli J
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1052230
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| Doc. No
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TL51347
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| Main Entry
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Kobayashi, Hirofumi
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| Title & Author
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Sediment Movement and Basin Evolution and Fill in a Shale-cored Deepwater Fold and Thrust Belt, NW Borneo Malaysia\ Kobayashi, HirofumiWood, Lesli J
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| College
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Colorado School of Mines
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| Date
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2019
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| Degree
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Ph.D.
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| student score
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2019
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| Note
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231 p.
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| Abstract
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This thesis investigates the deformation and sedimentation in deepwater fold and thrust belts (DWFTB) to better understanding of the manner in which structure and sedimentation interact. First, this thesis reviews the existing published literature for the known state of DWFTB development and fill processes, and confirms what appear to be the primary observations of previous researchers on what variables at the basin- to fold-scales most affect the structural style and sedimentation in DWFTB setting. These observations confirm that both the tectonic setting and the nature of the deep substrate (i.e. salt vs shale), and the volumes of incoming sediments are three primary variables of most influence. These observations provide the hypothesis of primary processes to examine the northwest (NW) Borneo DWFTB. Second, this thesis documents the tectono-sedimentary sequences of the offshore, NW Borneo DWFTB using three- and two-dimensional seismic data and borehole data. The analysis of the seismic sequence stratigraphic framework, termination pattern-based seismic external forms, and depositional seismic facies-analysis combined with the growth strata interpretation identifies the pre-, the syn-, and the post-kinematic sequences. These sequences are examined for the manner in which structure and sedimentation interact to form basins and fill basins. Third, this thesis characterizes marine mass transport complexes (MTCs) in the NW Borneo DWFTB using the three dimensional seismic, borehole logs, and available biostratigraphic assemblages, and documents the impact of these catastrophic events on the sediment pathways. Some of the key observations from this study regarding structure and sedimentation include: 1. Larger scale, long-lived structures (regional fold segment boundaries) are key to the long-term nature of a basin fill because they often form the long-lived sediment inputs to the basin. Smaller scale, shorter-time frame structural elements (folds and thrusts) might control the higher frequency on-off switch for sediment input into sub basins. 2. Fold growth is not equant across a structure. Locations of sediment bypass across a structure will change through time, becoming active and dormant as the structure grows. 3. The focal area of uplift and the timing of increased uplift of a growing fold are well identified by the lateral and vertical transitions in seismic external form along the strike of the fold. These variations in seismic external form are accompanied by the changes in depositional seismic facies; the development of submarine channel facies and the occurrence of mass transport complexes facies. Thus combined mapping of both seismic external form and facies is essential to constrain the interaction between structure and sedimentation in DWFTB setting. Some of the key observations from this study regarding seismic scale mass transport processes and complexes(MTCs) include: 1. Attached MTCs are more readily related to large progradation and shelfal sediment loading in response to regional tectonics or sea level changes. 2. Detached MTCs are related to local gravitational instability in the steepened forelimb slope of anticlinal folds by amplified and rotated by folding processes. 3. Emplacement of large, attached MTCs can form topography on the seascape that results in complete redirection of FTB gravity flows. 4. Attached MTCs contain an abundance of neritic fauna and flora, elevated density readings, and may contain large transported blocks and sandier lithologies that can compromise seal integrity. 5. Detached MTCs show unusually high width: length ratios due to confinement in the run-out direction. May prove to be better seals due to their likely muddier nature, but this is highly dependent on the nature of the failed strata. 6. Syn-kinematic attached MTCs show low width: length ratios due to lateral confinement in the run-out direction by anticlines. These MTCs display increased thicknesses per volume distributions compared to global attached systems, probably reflecting that the tractional and cohesive nature of MTCs causes them to build thicker deposits when confined.
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| Descriptor
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Geology
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Petroleum geology
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Sedimentary geology
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| Added Entry
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Wood, Lesli J
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| Added Entry
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Colorado School of Mines
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