Dynamic Crustal Recycling and Surface Processes at the Suture Zone of Arc-Continent Collision: Insights from Deep-Time Sedimentary Stratigraphy and Modern Landscape of the Coastal Range, Eastern Taiwan

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dc.contributor.advisorDorsey, Rebecca
dc.contributor.authorLai, Larry Syu-Heng
dc.date.accessioned2023-03-24T18:53:53Z
dc.date.available2023-03-24T18:53:53Z
dc.date.issued2023-03-24
dc.description.abstractThe arc-continent collision system has been considered as a primary mechanism in the growth of continental crust, which involves development of both rising eroding mountains and subsiding syn-orogenic basins. However, the rates, timescales, and structural controls on these processes remain poorly understood. In this dissertation, I address these questions through stratigraphic and geomorphic studies in the Coastal Range of eastern Taiwan, an active arc-continent collisional orogen. The first portion of this work focuses on long-debated origin of the Lichi Mélange and associated basin evolution in the southern Coastal Range. Results of integrated stratigraphic and lithofacies analysis reveal a polygenetic origin (sedimentary deposit overprinted by structural shears) of the Lichi Mélange. This mélange unit is interbedded with orogen-derived turbidites that accumulated on accreting island-arc basement in a retrowedge foredeep basin from ca. 4.0 to 0.8 Ma. The next chapter investigates vertical crustal motions involved in creation of the modern Coastal Range. I applied high-resolution backstripping procedures to composite sections in southern and northern Coastal Range, using updated age constraints and foraminifera-based paleobathymetry. The results reveal abruptly oscillating vertical motions in the accreting arc crust, which can be interpreted by an eastward migrating flexural wave, followed by an extremely rapid uplift via transpressional deformation since 0.8-0.5 Ma. In the following chapter, I further conducted quantitative topographic analysis to evaluate the primary controls on the landscape patterns in the modern Coastal Range. The results show that, in this fast-eroding terrain, channel steepness and hillslope gradient are independent of uplift rate but systematically vary with bedload grain size and bedrock lithology. High flux of coarse sediment and ubiquitous mass-wasting hillslopes together dominate erosion processes and set the topographic limit of the Coastal Range. These three chapters collectively present a comprehensive investigation into the genesis of Taiwan’s Coastal Range, from a subsiding deep-marine sedimentary basin millions of years ago to a rapidly emerging steep mountain belt today. The results provide novel perspectives in understanding how rock cycle, crustal deformation, and topographic evolution interact in an active mountain-building zone. This dissertation includes previously published co-authored materials with electronic data spreadsheets in supplemental files.en_US
dc.identifier.urihttps://hdl.handle.net/1794/28074
dc.language.isoen_US
dc.publisherUniversity of Oregon
dc.rightsAll Rights Reserved.
dc.subjectArc-continent collisionen_US
dc.subjectCrustal recyclingen_US
dc.subjectMélangeen_US
dc.subjectSedimentary basin analysisen_US
dc.subjectTaiwan Coastal Rangeen_US
dc.subjectTectonic geomorphologyen_US
dc.titleDynamic Crustal Recycling and Surface Processes at the Suture Zone of Arc-Continent Collision: Insights from Deep-Time Sedimentary Stratigraphy and Modern Landscape of the Coastal Range, Eastern Taiwan
dc.typeElectronic Thesis or Dissertation
thesis.degree.disciplineDepartment of Geological Sciences
thesis.degree.grantorUniversity of Oregon
thesis.degree.leveldoctoral
thesis.degree.namePh.D.

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