乌江流域中-新生代以来构造运动的碎屑磷灰石裂变径迹证据  

The Detrital Apatite Fission-track Evidence for Tectonic Processes since Mesozoic—Cenozoic in Wujiang River Catchments

作　　者：张君[1] 李长安[1,2] 孙习林[1] 

机构地区：[1]中国地质大学(武汉)地球科学学院,武汉430074 [2]教育部长江三峡库区地质灾害研究中心,武汉430074

出　　处：《地质论评》2013年第3期537-543,共7页Geological Review

基　　金：国家自然科学基金资助项目(编号40971008)的成果

摘　　要：通过对乌江河漫滩现代沉积物中碎屑磷灰石裂变径迹年代学分析,得到3个峰值年龄:P1--5.9Ma;P2--27.6Ma;P3--82.3Ma。分析认为,各峰值年龄分布主要受阶段性的构造活动影响,并与中—新生代以来乌江流域发生的重大构造事件的时限相吻合,指示裂变径迹年龄峰值记录了云贵高原东部中—新生代以来构造演化的重大事件。其中,P3峰值年龄主要受控于晚白垩世隆升作用,P2峰值年龄主要受晚渐新世缓慢隆升和断裂构造作用控制,P1峰值年龄主要受控于中—上新世之交发生的区域性构造抬升作用。P1峰值年龄的颗粒数占总颗粒数比重最大,高达40.7%,指示在5.9Ma发生了大规模的区域性构造隆升事件,在如此大规模的地表抬升运动和气候变化的共同作用下,河流的侵蚀能力得到增强,乌江流域的深切河谷地貌应该形成于5.9Ma以后。Based on the detrital apatite fission track analysis on the modern sediment from flood plain in the Wujiang River, we plotted out 3 peak values： P1-5.9Ma; P2-27.6Ma; P3-82.3Ma, all the peaks resulted from the periodical tectonic events occurred in the Wujiang River catchments. The consistency between a series of important tectonic events and experimental results reveals that the fission track ages recorded important tectonic events in the eastern Yunnan-Guizhou Plateau since Mesozoic-Cenozoic. The main control factors of P3, P2 and P1 are uplift movements in the Late Cretaceous, slowly uplifting as well as faulting in the late Oligocene and regional quickly uplift events in the Miocene-Pliocene respectively. Among the results, the large scale regional tectonic uplift events as indicated by P1 associated with climate change accelerated significantly erosion process, which implies that deep gorgecutting by the Wujiang River most likely formed after 5.9Ma.

关 键 词：乌江流域 碎屑磷灰石 裂变径迹 构造运动 下切侵蚀 

分 类 号：P534.6[天文地球—古生物学与地层学]