摘要
中-晚侏罗世随着劳亚大陆与冈瓦纳大陆的裂解、北大西洋的开启以及古特提斯洋的闭合,导致全球海平面的改变和气候波动。在中-晚侏罗世交界的卡洛期-牛津期,西特提斯域广大地区的气候从冷湿转变为干热,羌塘盆地位于特提斯喜马拉雅构造域东段,它是否也有类似的气候变化特征？文章对羌塘盆地雁石坪剖面中、上侏罗统夏里组沉积物中Ca CO3、赤铁矿和针铁矿环境代用指标进行了测定,并结合岩性和沉积相变化分析了该区古气候变化,研究结果表明：中-晚侏罗世交界时期,羌塘盆地雁石坪地区气候变化经历了早期（163.8-162 Ma）相对冷湿、中期（162-161.4 Ma）半干旱以及晚期（161.4-159.6 Ma）干旱3个演化阶段。显示羌塘盆地中-晚侏罗世交界时期（163.8-159.6 Ma）的气候变化与同一时期的西特提斯构造域气候变化趋势一致,为羌塘盆地侏罗纪可能的成盐潜力研究和评价提供了重要的古气候依据。
The separation of Laurasia land and Gondwana land and the opening of the Atlantic Ocean as well as the extinction of the Palaeotethys Ocean in late Jurassic probably led to severe sea level change and climate fluctuation. Recent studies show that global climate was not always warm in late Jurassic. On the contrary, the world underwent a violent period of climate change, turning from cold wet to drought and hot during the Callovian-Oxfordian transition of the vast region of the west Tethys. In order to determine whether similar climate shifts might have happened in the East Tethys, the authors took the sediments from the Xiali Formation of Yanshiping Section in the Qiangtang Basin as the study object, measured CaCO3, hematite and goethite, and analyzed lithologic changes with the purpose of summarizing the characteristics of the palaeoclimatic evolution. Some conclusions have been reached： Climate change in 163.8-159.6 Ma could be generally divided into three stages. The first stage（163.8-- 162 Ma）was probably humid, the second the third stage（161.4-159.6 Ma）was characterized by stage （ 162 - 161.4 Ma） might have been semiarid and aridification. It is thus held that the climate change at the late stage of the Middle Jurassic period （163.8- 159.6 Ma） of the Qiangtang Basin in East Tethys responded to the Paleoclimatic evolution of West Tethys. In the light of climate evolution, the results achieved by the authors will help to evaluate the halite-forming potential at the late stage of the Middle Jurassic period.
出处
《矿床地质》
CAS
CSCD
北大核心
2014年第5期993-1002,共10页
Mineral Deposits
基金
国家973重点基础研究发展计划项目(编号:2011CB403003)的资助
