山西吕梁山地区中—新生代隆升剥露过程：磷灰石裂变径迹证据-《地球科学与环境学报》

文章信息/Info

Title:: Mesozoic-Cenozoic Uplift-exhumation History in Luliangshan Area of Shanxi: Evidences from Apatite Fission Track

作者:: 任星民; 朱文斌; 朱晓青; 王玺; 罗梦; 1. 南京大学地球科学与工程学院,江苏南京 210046; 2. 中国地质调查局青岛海洋地质研究所,山东青岛 266071; 3. 河海大学文天学院,安徽马鞍山 243031

Author(s):: REN Xing-min; ZHU Wen-bin; ZHU Xiao-qing; WANG Xi; LUO Meng; 1. School of Earth Sciences and Engineering, Nanjing University, Nanjing 210046, Jiangsu, China; 2. Qingdao Institute of Marine Geology, China Geological Survey, Qingdao 266071, Shandong, China; 3. School of Wentian, Hohai University, Ma’anshan 243031, Anhui, China

Keywords:: low temperature thermochronology; uplift-exhumation; fission track; Mesozoic-Cenozoic; tectonic-thermal event; basin-mountain coupling; Shanxi

摘要:: 运用磷灰石裂变径迹热年代学方法研究了华北克拉通吕梁山地区前寒武系杂岩体及其周边盆地的构造热演化过程,这对于进一步探讨和认识华北克拉通演化和破坏等科学问题有重要意义。结果表明:山西吕梁山地区磷灰石裂变径迹年龄分布于40~138 Ma,记录了吕梁山地区早白垩世以来的冷却事件;裂变径迹年龄与海拔高程呈正相关关系,线性相关系数为0.789;磷灰石颗粒的围限径迹长度范围为10.62~12.99 μm,远小于其初始长度(16.3 μm),表明样品经历了长期的退火过程?磷灰石裂变径迹时间-温度模拟结果表明吕梁山地区经历了两期快速隆升:第1期冷却事件对应晚侏罗世—早白垩世吕梁山山体发生的剧烈冷却抬升,该事件使得样品进入部分退火带,随后长期处于部分退火带;第2期则表现为渐新世以来吕梁山地区出现伸展造山运动,与山西地堑系形成盆山耦合,山体快速隆升剥蚀。此外,中新世末(约9 Ma)以来,青藏高原快速隆升向东扩展的远程效应对吕梁山地区构造的影响不明显。

Abstract:: Tectonic-thermal evolution processes of Precambrian complex in Luliangshan area of North China Craton and its peripheral basin were studied by the means of apatite fission track thermochronology in order to further discuss and recognize the evolution and breakup of North China Craton. The results show that the apatite fission track ages in Luliangshan area of Shanxi are 40-138 Ma, recording the cooling events since Early Cretaceous; fission track ages are positively correlated with the altitudes, and the correlation coefficient is 0.789; the confined track lengths of apatite particles (10.62-12.99 μm) are much shorter than the original length (16.3 μm), indicating that the samples suffer a long annealing process. The time-temperature simulation results of apatite fission track show that there are two rapid uplifts in Luliangshan area. For the first rapid uplift, severe cooling uplift of massif happens from Late Jurassic to Early Cretaceous in Luliangshan area, and the event makes the samples into the partial annealing zone, and subsequently keeps in the zone; for the second rapid uplift, the extending orogeny, which happens since Oligocene in Luliangshan area, is basin-mountain coupling with Shanxi graben, and the massif suffers from rapid uplift and denudation. In addition, the effect of rapid uplift extension eastward of Qinghai-Tibet Plateau since the latest Miocene (about 9 Ma) is not significant on the structure in Luliangshan area.