摘要:与简单盆地和叠合盆地中-浅层相比,叠合盆地深层往往缺乏镜质体反射率等传统古温标,海相碳酸盐岩层次往往缺乏磷灰石、锆石等重矿物而无法开展裂变径迹和(U-Th)/He分析,而且经历了多期复杂热史,古温标早期热记录被后期构造—热事件叠加改造,因此单一古温标和单一的热史恢复模式难以满足叠合盆地深层构造—热演化研究。本文从沉积盆地构造—热演化基本研究方法入手,着重介绍了发展迅速的多种显微组分荧光分析(FAMM)和二元同位素技术。针对叠合盆地深层多期复杂热史恢复的难点,以四川盆地为例总结了开展叠合盆地深层构造—热演化研究的思路和工作方法。叠合盆地深层构造—热演化研究应坚持今古地温场并举、盆地热演化与区域构造演化相结合、地质—地球物理—地球化学三位一体的总体工作思路,多温标耦合,正、反演结合,既考虑岩石圈热演化的动力学规律,又考虑该演化过程对盆地基底沉降、地层发育、古温标热演化程度的影响,只有这样才能保证叠合盆地深层构造—热演化研究结果的可靠性。
关键词: 构造—热演化/
多期复杂热史/
叠合盆地/
四川盆地
Abstract:Compared with the simple basin and shallow zone of superimposed basin, the deep zone of superimposed basin is usually lack of vitrinite reflectance and other traditional paleothermometer, and has experienced several complicated thermal history. Because the early thermal recording was superimposed by later tectonic thermal events, single paleothermometer or single thermal history reconstruction model is difficult to apply. Unfolding itself first with methods of tectono-thermal reconstruction of sedimentary basins, the idea and method system of the tectono-thermal evolution reconstruction for the deep zone in superimposed basin are summarized according to the difficulties on reconstruction of multiple-episode thermal evolution history and taking the Sichuan Basin for an example. The thermal evolution research for deep zone of superimposed basin should adhere to three general principles: 1)The thermal history reconstruction should be based on the study of present geothermal field; 2)The thermal evolution of the basin should combine with regional tectonic evolution; 3)The geological, geophysical, and geochemical method are trinity. Moreover, the method system should combine forward with inverse modeling. Both the kinetics of lithospheric tectono-thermal evolution and the thermal evolution stage of paleothermometers are should considered.
Key words:Tectono-thermal evolution/
Multiple-episode thermal evolution/
Superimposed basin/
The Sichuan Basin
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