龙门山中、南段中-新生代隆升史:来自裂变径迹的证据

运用裂变径迹年代学方法对龙门山中、南段中生代地层内的磷灰石、锆石进行分析,并进行了热历史模拟,结果表明:①龙门山中、南段天全、怀远一带中生代地层最主要的强烈隆升阶段为喜山晚期,与该区的强烈构造运动时期相一致;②怀远镇西南侧及西侧剖面,喜山晚期强烈隆升阶段的时间自西侧的20Ma左右开始至东侧的7～5Ma开始并延续至今,开始强烈隆升的时间自西向东逐步变新;与龙门山造山带逆冲推覆作用在时空上具向东前展式渐进推覆的特点相对应;③部分地区存在163～155Ma、140～77 Ma、55～22Ma的隆升事件.

Uplifting history of Meso-Cenozoic era in the central-southern part of Longmenshan region: Evidence from the fission-track ages.

Through fission track chronology method, we have analyzed apatite and zircon of the Mesozoic sequence in the central-southern Longmenshan and simulated the thermal history and got the following results: (1) the Mesozoic sequence at the Tianquan-Huaiyuan area in the central-southern Longmenshan had the strongest uplift in the Late Himalayan stage, coincident with the strong structure movement in the region. (2) For the profiles at southwestern and western Huaiyuan Town, the rapid uplift in Late Himalayan initiated from 20Ma in the west to 7~5Ma in the east and continued up to now, i.e., the beginning time of the uplift became younger from west to east, which is well corresponding with the eastwards progressive thrusting of the Longmenshan orogeny. (3) Some of local uplift events occurred at 165~155Ma, 140~77Ma and 55~22Ma.