摘要
通过对西昆仑北部山前的碎屑锆石裂变径迹年代学分析,将年龄划分为8个峰值区间:P1—4.7Ma以来;P2—13～9Ma;P3—24～18Ma;P4—47～33Ma;P5—79～57Ma;P6—131～103Ma;P7—185～180Ma;P8—267～235Ma,各峰值分布受阶段性抬升剥露和热事件共同影响。P8与P5主要受热事件控制,P6、P4、P3、P2、P1主要和抬升剥露有关,P7主控因素不明显。裂变径迹年龄峰值与西昆仑及邻区发生的一系列重大构造事件的时限吻合,并伴随强烈的区域性断裂活动,指示裂变径迹年龄峰值记录了西昆仑及邻区构造演化的重大事件;其中,晚白垩世以来喜马拉雅东、西构造结抬升具有相似性,反映了青藏高原自印度板块与欧亚大陆碰撞以来经历了相似的阶段性抬升。柯克亚连续沉积剖面显示西昆仑及邻区4.7Ma以来开始最后一次大规模抬升,并指示上新世以来西昆仑及邻区的径迹年龄储备表现出由多样性向一致性、由无规律向年轻化的发展趋势,暗示4.7Ma以来的抬升具整体抬升性质;3.6Ma为抬升的转折点,表现为抬升剥露速率加快、基底开始大规模出露地表,西昆仑山对南边的水流形成障碍。
Based on the detrital zircon fission-track age analysis on the northern foot of the western Kunlun Mountains,we plotted out 8 ranges of peak values,P1：since 4.7 Ma,P2：13-9 Ma,P3：24-18 Ma,P4：47-33 Ma,P5：79-57 Ma,P6：131-103 Ma,P7：185-180 Ma,P8：267-235 Ma;all the peaks resulted from the periodical uplift and thermal events.The main control factor of P8 and P5 are thermal events;and that of P6,P4,P3,P2,P1 are uplift and exhumation;the cause of P7 is unsure.The consistency of a series of important tectonic events and associated intensive regional fault activities reveal that the fission-track peaks recorded important tectonic events around the western Kunlun Mountains and adjacent regions;among them,the uplifts of west and east tectonic syntaxes of the Tibetan plateau since the late Cretaceous are similar,which reflects that the Tibetan plateau underwent similar periodical uplifts since the collision between Indian and Eurasian plates.The continuous depositional succession of Kekeya reveals that 4.7 Ma was the beginning of the last large scale uplift,and it shows that the fission-track age trend evolved since the Pliocene from diversity to simplicity and from irregularity to becoming younger in these regions.It implies that the uplifts behaved as an integration and 3.6 Ma was the turning point of uplift process,since then the uplift and exhumation rate had been accelerated,most of the basement rocks began to outcrop onto the surface and the western Kunlun Mountains became the obstacle to the currents from the south.
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2010年第3期64-78,共15页
Earth Science Frontiers
基金
国家自然科学基金项目(40672137
40902060)
中国地质调查局项目"青藏高原新生代地质作用过程与第四纪环境演变综合研究"(1212010610103)
中国石油化工股份有限公司项目"塔里木区块构造-岩相古地理研究与编图"
关键词
西昆仑
碎屑锆石
裂变径迹
峰值
抬升
the Western Kunlun
detrital zircon
fission track
peak values
uplift
作者简介
刘函（1986-），男，硕士研究生，构造地质学专业，主要从事构造年代学及造山带地质学方面工作。E-mail：abc23982112@163．com
通讯作者：王国灿。E-mail：wgcan@cug．edu．cn
