Present-day heat flow, thermal history and tectonic subsidence of the East China Sea Basin
Present-day heat flow, thermal history and tectonic subsidence of the East China Sea Basin
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DOI：
10.1016/j.marpetgeo.2004.05.007
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发表时间：
2004-11
影响因子：
4.2
通讯作者：
Shuchun Yang;Shengbiao Hu;Dongsheng Cai;X. Feng;Linlin Chen;Le Gao
中科院分区：
文献类型：
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作者：
Shuchun Yang;Shengbiao Hu;Dongsheng Cai;X. Feng;Linlin Chen;Le Gao
东海盆地位于欧亚板块、太平洋板块和菲律宾海板块的交汇区域，由西有台北坳陷、东有西湖坳陷两个坳陷组成。热流测量结果表明，东海海盆现今热流在70.6mW/m2左右，变化范围在55 ~ 88mW/m2之间。西湖和台北低气压之间的热流没有显著差异。利用镜质组反射率重建热历史表明，台北坳陷与西湖坳陷的热历史不同。台北坳陷前第三系在古新世末温度最高时的古热流值平均达到82mW/m2，远高于现今的热流值。西湖坳陷下第三系沉积在渐新世末温度最高（35.4 ~ 23.3 ma），平均古热流值为83mW/m2。构造沉降分析表明，整个东海盆地主要裂陷期的时间存在差异。台北坳陷在晚白垩世（~ 65Ma）至早始新世（~ 55Ma）期间发生裂陷，在晚始新世至中新世末（23.3 ~ 5.2 ma）期间发生热沉降。西湖坳陷初期沉降持续至中新世早期，热沉降持续至中新世末期。从上新世到现在，整个亚洲西太平洋边缘都发生了加速下沉。盆地内不整合面剥蚀厚度显著，台北坳陷古新世剥蚀量为1147m，渐新世以上剥蚀量为1208m，西湖坳陷渐新世剥蚀量为1409m。
The East China Sea Basin is located in the convergence area between the Eurasian plate, the Pacific plate and the Philippine Sea plate, and consists of two depressions, the Taibei Depression in the west and the Xihu Depression in the east. Heat flow measurements show that the East China Sea Basin is characterized by present-day heat flow around 70.6mW/m2, varying between 55 and 88mW/m2. No significant difference in heat flow is observed between the Xihu and the Taibei Depressions. Thermal history reconstruction using vitrinite reflectance suggests that the thermal history was, however, different in the Taibei and the Xihu Depressions. Paleo-heat flow values when the pre-Tertiary formations experienced their maximum temperature at the end of the Paleocene reached a mean of 82mW/m2in the Taibei Depression, much higher than the present-day value. The lower Tertiary sediments in the Xihu Depression experienced maximum temperatures at the end of Oligocene (35.4–23.3Ma) and reached a mean paleo-heat flow value of 83mW/m2. Tectonic subsidence analysis shows that the timing of the major rifting episode was different across the East China Sea Basin. The rifting occurred from the Late Cretaceous (∼65Ma) to the early Eocene (∼55Ma) in the Taibei Depression, followed by thermal subsidence from the late Eocene to the end of Miocene (23.3-5.2Ma). In contrast, in the Xihu Depression the initial subsidence lasted until the early Miocene and thermal subsidence to the end of Miocene. From Pliocene to the present, an accelerated subsidence took place all along the West Pacific margin of Asia. Significant thicknesses of strata were removed from the unconformities in the basin: the mean amount of erosion was 1147m from the Paleocene and 1208m above the Oligocene in the Taibei Depression, and 1409m from the Oligocene in the Xihu Depression.