Sediment transport processes across the Tibetan Plateau inferred from robust grain-size end members in lake sediments

• DOI: 10.5194/cp-10-91-2014
• Publication Date: 2014-01-16T06:18:15Z
• Authors: E. Dietze; F. Maussion; M. Ahlborn; B. Diekmann; K. Hartmann; K. Henkel; T. Kasper; G. Lockot; S. Opitz; T. Haberzettl
• Keywords: Deposition

Abstract. Grain-size distributions offer powerful proxies of past environmental conditions that are related to sediment sorting processes. However, they often multimodal character because sediments can get mixed during deposition. To facilitate the use grain size as palaeoenvironmental proxy, this study aims distinguish main detrital processes contribute lacustrine sedimentation across Tibetan Plateau using grain-size end-member modelling analysis. Between three and five robust subpopulations were distinguished at different sites from similarly–likely model runs. Their modes grouped linked common transport depositional be associated with contemporary climate (precipitation patterns lake ice phenology, gridded wind shear stress data High Asia Reanalysis) local catchment configurations. The coarse sands clays >250 μm <2 probably transported by fluvial Aeolian (~200 μm) dust (~60 μm), saltation in near-surface suspension clouds, occasional westerly storms winter spring. Coarse regional ~25 may derive near-by sources keep longer term suspension. continuous background is differentiated into two end members (modes: 5–10 2–5 represent sources, directions and/or trapping dynamics long-range, upper-level episodic northerly transport. According only origin small amounts mean (19± 5%), whereas aeolian deposition dominate clastic lakes (contributions: 42 ± 14% 51 11%). alluvial reworking material nearby slopes summer seems limit interpretation should crosschecked other proxy information. If not considered a stand-alone high transferability regions archives allows helpful reconstructions history.