构造和气候共同控制下的藏南热隆盆地中更新世以来的演化

热隆盆地是亚东－谷露裂谷系南部, 由宁金抗沙西麓断裂控制的断陷盆地, 根据野外地质调查、 遥感(RS)和数字高程模型(DEM)分析, 盆地内发育有三期洪积扇, 形成时代分别在中更新世中期(第一期)、 中更新世中期至晚更新世早期(第二期)、 晚更新世晚期(第三期)。 这三期洪积扇的发育分别对应于间冰期和间冰阶的高温大降水时期, 表明在第四纪以来, 由于间冰期与间冰阶期的到来, 温度升高, 降雨量增加, 地表径流作用增强, 先成洪积扇被破坏, 新洪积扇形成。 盆地内自中更新世中晚期以来剥蚀程度自北向南减弱, 表明在整体抬升的背景下, 由于宁金抗沙西麓断裂的活动, 使得盆地北部基岩抬升速率大于南部, 形成自北向南的掀斜。

Evolution of Relong Basin in southern Tibet controlled by both tectonics and climate since mid-Pleistocene

Relong Basin(RLB) is a fault basin,part of the southern Yadong-Gulu rift system,controlled by the Ningjinkangsha west piedmont fault(NWPF).Field mapping,remote sensing and digital elevation model analyses revealed three stages of alluvial fans distributing in the RLB.The first stage is that the fan formed at middle mid-Pleistocene,the second formed at early later Pleistocene,and the third formed at later later-Pleistocene.The three stages are corresponding to the interglacial and great precipitation epoch in the interstadial.In later Quaternary,in the interglacial and interstadial,with temperature rising,precipitation adding and runoff increasing,old fans were eroded and the new fans started forming.The rock uplift continues in later Quaternary in the area of RLB.Owing to the activity of NWPF,the RLB tilts from north to south and the denudation decreased from north to south since mid-Pleistocene.