【摘要】 气候-构造相互作用是目前固体地球和全球变化中最前沿的核心科学问题,地表侵蚀是气候-构造之间的桥梁纽带,地层沉积速率则是地表侵蚀强弱的直接响应。祁连山北缘-河西走廊在约4～2Ma期间沉积了一套粗粒相磨拉石-玉门砾岩,是研究气候-构造相互作用的一个理想产物,目前其气候或构造的主要成因存在争议。本文尝试阐述祁连山北缘-河西走廊地区4～2Ma期间玉门砾岩形成主要诱因是气候?还是构造?在磁性地层年代学控制下,同时期内玉门砾岩沉积速率从西北向东南减少的趋势与现今地貌的西北-东南减少趋势相一致,而与西北-东南增加的现今年平均降水量相异,因此认为地貌高差应为玉门砾岩沉积速率时空变化的主要诱因,此时期内该地区构造隆升可能驱了气候变化。更多还原

【Abstract】 The climate-tectonics interaction is one of the frontiers of studies on global climate change and solid earth sciences in last decades. The key for deciphering this issue is the surface erosion,and the sedimentation rate is particular. The thick molasse,namely,the Yumen Conglomerate,deposited from 4Ma to 2Ma in the Hexi Corridor of NW China,is an ideal object for the investigation of climate-tectonics interaction. In this paper,we try to decipher the chief trigger for the formation of the conglomerate. Based on published magnetostratigraphic data,during the same interval the northwestwards sedimentation rate increasing trend of the Yumen Conglomerate is coincident with the present day topography rather than the annual precipitation. During the deposition of the Yumen Conglomerate,tectonics might be the predominant factor controlling the regional sedimentation rate and surface erosion rate,though climate might still has a role to play. In conclusion,the tectonics might be the most important factor controlling the regional climate change during the Yumen Conglomerate deposited intervals.更多还原