摘要
本文以渤海湾盆地为例 ,讨论通过定量研究镜质体反射率剖面资料来重建沉积盆地构造演化特征。结果表明渤海湾盆地曾经历过与印支运动和燕山运动相对应的两次重要的构造抬升、剥蚀事件。估算的这两次构造抬升作用剥蚀的地层厚度分别平均约为 1 1 1 0m和 90 0m ,剥蚀速率分别为 35～82m/Ma和 8～ 1 7m/Ma。研究表明渤海湾盆地不同地史时期古地温梯度不同 ,中生代古地温梯度 ( 4 .33～ 4 .6 7℃ / 1 0 0m)明显高于晚古生代 ( 3.4 9～3.92℃ / 1 0 0m)和新生代 ( 3.75～ 3.76℃ / 1 0 0m)以及现代地温梯度 ( 3.5～3.7℃ / 1 0 0m) ,这表明本区在中生代时曾出现过高热异常。镜质体反射率剖面回归参数 (热响应因子b)反映出渤海湾盆地在新生代沉降速度明显加大 ,此时控制盆地沉降作用的构造背景发生了重大的变化 ,强烈的坳陷和断裂作用取代了晚古生代地台和中生代的断陷而成为本区最重要的构造特征。
Systematic measurements and quantitative analysis of vitrinite reflectance data from the Bohai Gulf Basin have revealed two tectonics and unconformities corresponding to the Late Paleozoic Mesozoic (Indo Sinian movement) and Mesozoic Eocene (Yanshanian movement) boundaries. The estimated thickness of the section that was removed by erosion during this two tectonic events is about 650～1520 m(average 1110 m) and 650～1200 m (average 900 m) , respectively. The rate of erosion is about 35～82 m/Ma and 8～17 m/Ma respectively, in which the first one (Indo Sinian movement) is larger than the second one (Yanshanian movement), suggesting that the Indo Sinian movement is more extensive and the uplift is stronger than that of the Yanshanian movement. The thermal response factor (b), which provides a useful tool for the sediment basin tectonics reconstruction, indicates a maximum subsidence rate of the Bohai Gulf Basin during the Eocene, which implies that the tectonic background had changed greatly since Eocene. Depression and faulting were the tectonic features in the Bohai Gulf Basin after that time.
出处
《矿物学报》
CAS
CSCD
北大核心
2001年第4期705-709,共5页
Acta Mineralogica Sinica
基金
国家自然科学基金项目 (批准号 :40 1730 0 5 )
中国博士后科学基金 ( 1999/10 )
贵州省自然科学基金 ( 99 30 91)
