• 责任者：Xu Zemin (Department of Civil Engineering ; Kunming University of Science and Technology ; Kunming 650224 ; China) ; Liu Wenlian
• 刊名：Earth Science Frontiers
• 出版年：2011
• 卷期：18(5)
• 关键词：上新世 ; Pliocene ; 沉积构造 ; sedimentary structure ; 青藏高原 ; Qinghai-Tibetan Plateau
• 页码：p.256-270
• 图表：illus., 22 refs.
• 分类号：1200
• issnNo：ISSN1005-2321
• isbnNo：CN11-3370/P

The vertical superimposition relationship between the Xigeda Formation and its overlying, underlying fluvial gravel layers is of great significance for indicating sedimentary environment. The Xigeda Formation, which is mainly made of horizontally laminated mottled fine-grained deposits often containing sandwiches of tens of centimeters of fluvial gravel layers, and the silt layers frequently contain cross-bedding and cross-lamination. The fluvial-lacustrine characteristics and the bottom currents in Xigeda lakes should be taken into account in the study of the genesis of the formation. The mineral components of Xigeda fine-grained deposits and the rock types of gravel layers within Xigeda Formation change with the geographic locations of outcrops. Xigeda Formation deposited primarily in landslide-dammed lakes; secondly in sag ponds derived from local subsidence of rivers, which developed along the fault zone.oft-com:office:office" />