A comparison on sedimentary processes between collisional versus wedges: examples fromoffshore Southwestern Taiwan and Barbados prism

Wei-Zhi Liao

Abstract

Barbados acrretionary wedge locates in Caribbean Sea at where south American plate subducts beneath Caribbean plate. Frontal collisional wedge off Southwestern Taiwan generated by oblique collision from Philippine plate to Eurasia plate. These two areas are similar in continent-ocean setting. Using the side-scan sonar system and 3.5kHz seismic profile combining core data to interpret the sedimentary process in southern termination of Barbados Prism, and interpret the frontal collisional wedge Southwestern Taiwan by the MCS-seismic profile. Comparing the similarities and dissimilarities of sedimentary process between these two area, then discuss with the comparison.

There are three types of surficial sediments identified on the South Barbados prism: (1) sediments derived form South American and hemipelagic or pelagic; (2) clay introduced by diapiric process; (3) deposits indurated by diagenesis. On the frontal collisional wedge Southwestern Taiwan, most of sediments derived from Taiwan orogen. Sediments contribute by other process are negligible.

Tectonic activity acts agreat role in sedimentary process on the South Barbados prism. The orientation of submarine canyon, distribution of mud diapirs, and sediments movement are influenced by the trend of fault. In Southwestern Taiwan, tectonic activity makes a chain of intraslope basins on collisional wedge. Sediments fill and spill basins, and develop some characters may display in seismic profile. Mud diapirs finally locate on the edge of intraslope basins.

Comparing these two area, sedimentary process are both influenced by tectonic activity and distribution of structure. But there are something different. The type of fault is not all the same in both area. The tectonic trend in frontal collisional wedge does not influence the pathway of sediment strongly like southern Barbados prism. And there is no bottom current erode on frontal collisional wedge offshore Southwestern Taiwan in evidence.

 

Reference

Yu, H.S. and Huang, Z.Y. (2006). Intraslope Basin, Seismic Facies and Sedimentary Processes in the Kaoping Slope, Offshore Southwestern Taiwan, Terr. Atmos. Ocean. Sci., 17(4), 659-677.

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Faugeres, J.C., Gonthier, E., Bobier, C., and Griboulard, R. (1997). Tectonic control on sedimentary processes in the southern termination of the Barbados Prism. Marine Geology,140, 117-140.

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