沉积物的矿物和地球化学特征与盆地构造、古气候背景

构造和气候的变化是盆地充填和演化的两个主要控制因素,对沉积物而言，其主要是对沉积物类型和分布的控制。从沉积物的矿物学和地球化学的角度，提取了与盆地构造和气候演变有关的主要参数，包括碳酸盐岩矿物中的δ¹³C、δ¹⁸O、石英/长石、高岭石/粘土、伊利石/粘土的比值，反演地质历史中盆地在构造和气候上的变化。对松辽盆地白垩系的研究表明，泉三段、泉四段中石英/长石低值代表了在盆地坳陷期存在着具有一定强度的构造运动。伊利石/粘土和高岭石/粘土的分析反映出松辽盆地白垩世的气候经历了由泉三段沉积期气候干旱到青山口组沉积期气候湿润、姚家组沉积期气候快速转向干旱、嫩一段沉积期湿润的气候和嫩三、四段沉积期湿热气候的演变。碳酸盐岩中碳、氧同位素分析显示松辽盆地在83.3 Ma左右发生了海侵事件，在82.8 Ma左右发生了海退事件。

Basin Tectonic Setting and Paleoclimate Revealed from Minerals and Geochemistry of the Sediments

Changes of tectonic setting and climate are two important controlling factors for basin filling and evolution. They control the types and the distributions of the sediments. In the view of mineralogy and geochemistry of sediments, some dominating parameters are used to study the evolution of the basin tectonic setting and climate in the geological history, including δ¹³C and δ¹⁸O of carbonates, quartz/feldspar, kaolinite/clay and illite/clay. The low value of the quarter/feldspar occurred in Quan Ⅲ and Quan Ⅳ sequences indicates that there were tectonic activities happened at that time. The analyses of illite/clay and kaolinite/clay show that the climate had undergone the changes from aridity in the Quan Ⅲ period to humidity in the Qingshankou period, quickly to aridity in the Yaojia period, to humidity in the NenⅠperiod, and to hot humidity in the Nen Ⅲ and Ⅳ period during the Middle Cretaceous in Songliao Basin. The analysis of the stable isotope of carbon and oxygen from the carbonates shows that there was a transgression event at 83.3 Ma and a regression event at 82.8 Ma in Songliao Basin.