OSL Dating of Paleo-Shorelines at Dagze Co, Central Tibetan Plateau

• Published in: Frontiers in Earth Science
• Main Authors: Wu, Yang, Chen, Yiwei, Huang, Long, Ding, Ping, Cui, Hao, Wei, Gangjian
• Format: Report
• Language: English
• Published: FRONTIERS MEDIA SA 2022
• Subjects: Geology; paleo-shoreline; OSL dating; Dagze Co; lake level change; Tibetan Plateau; Geosciences; Multidisciplinary; SUMMER MONSOON; ASIAN MONSOON; QINGHAI LAKE; BEACH RIDGES; TANGRA YUMCO; ICE CORE; HOLOCENE; LUMINESCENCE; CLIMATE; BASIN; Tangra; ice core
• Online Access: http://ir.gig.ac.cn/handle/344008/68258; https://doi.org/10.3389/feart.2022.940013

Well-preserved paleo-shoreline systems suggest lake shrinkage occurred in a vast region of the Tibetan Plateau, indicating dramatic paleo-environmental changes that linked closely to variations in Asian monsoon precipitation, glacial meltwater, and evaporation. The elevation and chronology of these shoreline features can be used to reconstruct lake level fluctuation history and regional paleo-climate. Here, we report optically stimulated luminescence (OSL) dating of 14 sediment samples from three of seven paleo-shorelines at south of Dagze Co, central Tibetan Plateau, using coarse-grained quartz and K-feldspar. Two fine grain silt samples were also measured. The results suggest the following: 1) The highest paleo-shoreline for Dagze Co has an elevation around 4,525 m (+55 m above modern lake). Its age is estimated to be 9.1 +/- 0.5 to 9.6 +/- 0.6 ka, suggesting a relative humid condition in the early Holocene. 2) After that, the lake level dropped similar to 20 m and remained relatively stable (+35 m) from similar to 8 to 5 ka, implying a dry condition with reduced runoff. Lake level further declined for similar to 40 m since about 5 ka. 3) The general trend of shrinkage for Dagze Co broadly matches studies from adjacent lakes, suggesting a common pattern of lake's evolution on the south/central plateau in the late Quaternary. The long-term decreasing trend of Asian monsoon precipitation should be the main reason.