台湾海峡地区新生代的构造演化

根据采集反射剖面,结合区域地质资料,分析了晋江凹陷、九龙江凹陷、新竹凹陷、台中凹陷和台湾凹陷为半地堑结构。新竹凹陷和台中凹陷下拗,演变为前陆盆地。晋江凹陷和九龙江凹陷因岩石圈上隆,其沉积较薄。这种模式决定了在台湾海峡地区,西部的生油气层为下第三系,而东部的生油气层为下第三系和上第三系。

CENOZOIC TECTONIC EVOLUTION OF THE TAIWAN STRAIT REGION

More than 10000km of seismic profiles have been acquired in the western part of the Taiwan Strait. According to the analysis of the profiles and regional geological data, the authors believe that Jinjiang Depression, Jiulongjiang Depression, Xinzhu Depression, Taizhong Depression and Taiwan Depression belong to half-graben structures. Thus, it is inferred that the Taiwan Strait region saw the formation of a series of extensional half-grabens due to the effect of extensional tectonic movement in eastern China in Late Mesozoic or Early Cenozoic. Within the grabens, the Lower Tertiary is filling sediment and Upper Tertiary and Quaternary are open-sea sediment. In the Pliocene, east-west collision of the Coastal Range caused the uplift of sedimentary basement in the east of Taiwan and Taiwan Depression, resulting in the formation of Taiwan Island and Taiwan Strait. Owing to the flexion of the lithosphere, Xinzhu and Taizhong Depressions are downwarped and evolved into a foreland basin with a relatively thick Upper Tertiary and Quaternary sediment. Jinjiang Depression and Jiulongjiang Depression have very thin Upper Tertiary and Quaternary sediment due to the upwarping of the lithosphere. This model leads to the fact that Lower Tertiary acts as oil-gas sources in the west of the Taiwan Strait region, while both Lower and Upper Tertiary are source rocks in the east.