兴化XH-1孔记录的苏北盆地晚新生代沉积体系及环境变化过程

The sediments sequence and environmental oscillation of the core XH-1 in Subei Basin since late Cenozoic

通过对位于苏北盆地中部的兴化XH-1孔350．08m连续岩芯的古地磁测年，确定了年代地层序列。在此基础上，对钻孔沉积物进行了以粒度特征为重点，包括矿物组成、结构、沉积构造和沉积组合在内的综合岩相古地理分析，划分出8个沉积相和19个沉积亚相。并根据沉积相的组合特征，将苏北盆地3．20Ma以来的沉积环境演化划分为沉降盆地-收缩湖盆～开阔平原湖泊～滩地湖沼4个大的阶段和8个沉积体系，恢复了盆地沉积环境演化从活动到稳定、从沉降到充填、从起伏到平坦的发展过程，分析了构造、沉积、气候及海平面变化对苏北平原形成的影响。通过对比，揭示了中国东部沉降盆地的地形、气候变化和水系重大调整与青藏高原隆升之间的藕合关系，其中发生在距今2．25～2．10Ma和1．90～1．72Ma左右的2次运动使盆地地形和水系发生重大调整，而发生在距今0．99Ma左右的昆黄运动导致东亚季风气候发生了重大的转型，冬、夏季风强度都显著增加，盆地沉积呈现出明显的周期性特征。

Based on paleomagnetism dating and the grain size of sediments, as well as the paleolitho facies analyzing like mineral composition, deposit structure and sediments assembly, we identified 8 sedimentary facies and 19 subfacies of the core XH-1 in Xinghua, Subei Basin. These facies show that the basin had come through four specific intervals as basin subside, construct lake, broad lake and shoal land 3.2 Ma BP. The changes of topography and the drainage system well recorded the two structure movements during the 2.25-2.10 Ma BP and 1.90-1.72 Ma BP. During and after the Kunhuang Movement 0.99 Ma BP, the sediments sequences varied abruptly and confirmed the transformation of the East Asian Monsoon during that time. Comparing the changes of topography, climate and the drainage system of the basin, we try to hold the clue of the coupling of the basin evolvement and the uplift of the Tibetan Plateau.