广西十万大山盆地中生代地层的裂变径迹研究及其地质意义  

Fission Track Analysis on Mesozoic Strata in the Shiwandashan Basin, Guangxi Province and Its Geological Significance

作　　者：周祖翼[1] 郭彤楼[1] 许长海[1] 杨风丽[1] 

机构地区：[1]同济大学海洋地质教育部重点实验室,上海200092

出　　处：《地质学报》2005年第3期395-401,共7页Acta Geologica Sinica

基　　金：国家重点基础研究项目(编号G2000047604);国家自然科学基金项目(编号40321603);教育部跨世纪优秀人才计划项目资助的成果

摘　　要：对采自中国南方十万大山盆地中生代地层的11个磷灰石样品和6个锆石样品进行了裂变径迹分析,所有磷灰石样品以及锆石样品SS-5、SW033、SW055的裂变径迹年龄数据均小于样品的地层年龄,表明这些样品在沉积后所经历的埋藏温度曾经大于最大退火温度。样品Shw-1、SW027、SW025的锆石裂变径迹年龄大于样品的地层年龄,反映的是源区的锆石年龄。根据磷灰石裂变径迹年龄数据进行的时间-温度历史模拟表明,十万大山地区的磷灰石样品基本反映了相同的低温段热演化史。各个样品在41～85Ma之间分别达到最大古地温值(介于98～175℃之间),此后各个样品的热演化史总体上呈冷却的趋势。自晚白垩世以来,盆地各地普遍遭受了抬升剥蚀过程,估算的地层剥蚀量在2281～4484m之间。Fission track analysis is carried out for 11 apatite samples and 6 zircon samples from Mesozoic strata in the Shiwandashan Basin, Guangxi Province in South China. Fission track ages for all apatite samples and 3 zircon samples are younger than their respective strata ages, which shows that the maximum burial temperatures for these samples exceeded the total annealing temperatures of the fission tracks. Zircon samples Shw-1, SW027, SW025 yield fission track ages that are older than their respective strata ages, reflecting the provenance ages of these zircons. Time-temperature history modeling based on apatite fission track analytical data shows that these samples experienced similar low-temperature history. These samples reached their maximum burial temperature (ranging between 98～175℃) during the period of 41～85 Ma, which was followed by a period of monotonous cooling and uplifting. Based on our modeling results, the amount of erosion since the Late Cretaceous is estimated to range between 2281～4484 m.

关 键 词：十万大山盆地 中生代地层 地质意义 磷灰石裂变径迹 广西 裂变径迹分析 裂变径迹年龄 十万大山地区 地层年龄 年龄数据 热演化史 地层剥蚀量 中国南方 退火温度 锆石年龄 历史模拟 晚白垩世 剥蚀过程 样品 低温段 古地温 

分 类 号：P534.5[天文地球—古生物学与地层学] TE122[天文地球—地质学]