Date Awarded

2013

Document Type

Thesis

Degree Name

Master of Science (M.Sc.)

Department

Virginia Institute of Marine Science

Abstract

The Lanyang Plain, along the northeastern Taiwan orogen, provides an excellent example of the tectonic and climatic controls on erosion and subsequent riverine sediment supply to the coastal ocean and deep sea. 12 deep borings on the Lanyang Plain and 2 long cores in Southern Okinawa Trough (MD12403, ODP1202), together with high-resolution seismic data on Ilan Shelf, provide a good record of the depositional history during Holocene, in both on-land and offshore areas. Based on these data, we find the sediment thickness reaches 216 m in Lanyang Plain, and the average sediment rate is estimated to be 3.6 Mt/yr - 5 Mt/yr in both the Lanyang Plain and the Ilan shelf. This value is higher than previous estimation of 2.6 Mt/yr by Kao and Milliman (2008).

We have divided on-land sedimentation rates over different periods (0-4 ka BP, 4-8 ka BP, and 8-12 ka BP) to document variations in Holocene sedimentation in response to event-enhanced and/or accommodation-space change. We find particularly high accumulation rates at 8-12 ka BP. Higher sedimentation rates noted in 2 offshore cores occurred at the same time. Together, this suggests greater sedimentation during this period, which we suggest may be related to the regional intensification of the southwest (summer) monsoon in Southern Asia, perhaps reflected by increased typhoon activity. Scrutinizing data from other previous studies, this event seems to have been characterized by higher sediment accumulation throughout Taiwan.

DOI

https://dx.doi.org/doi:10.25773/v5-v8ng-wk84

Rights

© The Author

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