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河流下切在岩溶区形成的多级层状洞穴,记录了地体隆升和地貌演化历史,但由于测年手段的限制,国内在这方面的研究一直进展不大。近年来,运用宇宙成因核素得到洞穴碎屑沉积物埋藏年龄的方法,已成为反演山地区域构造-地貌演化的新途径。本文尝试运用宇宙成因核素~(26)Al/~(10)Be埋藏测年技术,对属于贵州荔波地区4层洞穴系统的黑洞(第二层)碎屑沉积物进行年龄测定,假设样品进洞前无埋藏史,测年结果显示黑洞年龄至少有1.06±0.23Ma,并且该地区三岔河流域的侵蚀速率为55.1±2.3m/Ma。这是对该地区洞穴测年的一次新探索,体现出洞穴沉积物宇宙成因核素埋藏测年技术在我国晚新生代地质地貌演化研究方面具有良好的应用前景。
The river cut the multilevel stratiform caves formed in the karst area and recorded the history of the uplift and evolution of the landform. However, due to the limitation of the dating method, there has been little progress in this field in China. In recent years, the use of cosmic nuclides to obtain burial ages of cave clastic sediments has become a new way to reverse the tectonic-geomorphological evolution in mountainous regions. In this paper, we attempt to determine the age of clastic sediments in the black hole (second layer) of a four-layer cave system in Libo, Guizhou, using the dating technique of ~ (26) Al / ~ (10) There is no burial history before entering the cave, and the dating results show that the black hole is at least 1.06 ± 0.23Ma in age, and the erosion rate in Sancha River in this area is 55.1 ± 2.3m / Ma. This is a new exploration of the age of caves in the area, which shows that the burial dating technique of cosmic genetic nuclides in the cave sediments has a good application prospect in the study of the evolution of the Late Mesozoic geomorphology in China.