Distribution and Characters of Gas Hydrate by Geological controls on Southwestern Taiwan
Speaker : Yi-chen Lin
Abstract
Bottom simulating reflector (BSR) is a key indicator for the existence of gas hydrate, delineating the bottom of the gas hydrate stability zone. On Southwestern Taiwan region, BSR has been observed from the active accretionary wedge to passive China continental margin.
In recent years, over 10000km of MCS reflection profiles have been collected. Four major occurrences of BSR type of ridge type, basin type, submarine-canyon type, and continental type, are recognized on the basis of the relationship of BSR to topographic and structural features. BSR can be identified along 50% seismic profiles by (Liu et al, 2006), 30% in the accretionary and 20% in the continental slope by (Lin et al, 2009). A BSR distribution map suggests that gas hydrates are distributed both in China continental slope as well as in the submarine Taiwan accretionary wedge and their type relationship with topographic.
Main characteristics of BSRs in the study area can be described as most occur beneath topographic highs and in general, a series of high-amplitude dipping reflectors beneath BSRs can be found. These features indicate that gas hydrate may accumulate preferably beneath topographic ridges especially underneath four-way-dip topographic closures.
References
Liu, C.-S., Schnurle, P., Wang, Y., Chung, S.-H., Chen, S.-C., Hsiuan, T.-H., 2006. Distribution and characters of gas hydrate offshore of southwestern Taiwan. Terr.Atmos.Ocean. Sci. 17, 615–644.
Lin, C.-C., Lin, A.T., Liu, C.-S., Schnurle, P., Chen, G.-Y., Liao, W.-Z., 2009. Geological controls on BSR occurrences in the incipient arc-continent collision zone offshore southwest Taiwan. Marine and Petroleum Geology 26, 1118–1131.