P512.2
国家重点基础研究发展规划项目(编号G1998040800)、国家自然科学基金(编号49972026,39972026)、中国科学院重点知识创新项目(编号KZCXZ-SW-117)和美国国家自然科学基金项目联合资助的成果
青藏高原东缘古近纪盆地的填图和沉积学研究表明,在青藏高原东缘区域性走滑-挤压构造背景下形成的古近纪盆地内广泛发育厚层—巨厚层状的紫红色粗碎屑岩系。其沉积特征指示为一种近源快速堆积的泥石流和辫状河道沉积体,形成于干旱炎热气候条件下的典型陆内冲积扇环境。盆地充填序列、粗碎屑岩层序、动植物化石和盆地内岩浆岩~(40)Ar-~(39)Ar年代学等综合研究结果表明,古近纪盆地内粗碎屑岩大约形成于38～29 Ma。该时期与青藏高原东缘北段(横断山地区)古近纪盆地的形成和南段(兰坪—思茅地区)大盆地的裂解时间基本一致,这很可能预示着青藏高原在晚始新世—早渐新世期间曾发生过整体的快速构造隆升。
Field mapping and sedimentologic investigations of Paleogene basins in eastern Tibet suggest that the depositional characteristics of widespread thick-bedded, purplish red, coarse-grained clastic series of Paleogene basins in the setting of regional strike-slipping and thrusting indicate that the series is a proximal and rapid-accumulating sediment body in debris flows and a fan-surface braided river in a typical dry and hot subaerial alluvial fan environment. The sequences of basin filling and coarse clastic rocks, fauna and sporopollen associations and 40Ar/39Ar dating confirm that the coarse clastic rocks formed in Paleogene basins in the period of 38 ~ 29 Ma, nearly coeval with the formation of the Paleogene basins in the northern segment (Hengduanshan area) and the disintegration of large basins in the southern segment (Lanping - Simao area). The sedimentologic characteristics of the Paleogene coarse-grained clastic rocks, basin tectonics and magmatic activity indicate that a rapid wholesale tectonic uplift may have occurred in the Tibetan Plateau from the Late Eocene to Early Oligocene.
周江羽,王江海,An YIN, BK HORTON, MS SPURLIN.2003.青藏高原东缘古近纪粗碎屑岩沉积学及其构造意义[J].地质学报,77(2):262-271.
ZHOU Jiangyu, WANG Jianghai, An YIN, B K HORTON, M S SPURLIN China University of Geosciences, Wuhan, Hubei, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, Guangdong, Department of Earth, Space Sciences, University of Cal.2003. Sedimentology and Tectonic Significance of Paleogene Coarse Clastic Rocks in Eastern Tibet[J]. Acta Geologica Sinica,77(2):262-271.
