¹⁰Be Exposure Ages Obtained From Quaternary Glacial Landforms on the Tibetan Plateau and in the Surrounding Area

Abstract

In situ terrestrial cosmogenic nuclide (TCN) exposure dating using 10Be is one of the most successful techniques used to determine the ages of Quaternary deposits and yields data that enable the reconstruction of the Quaternary glacial history of the Tibetan Plateau and the surrounding mountain ranges. Statistical analysis of TCN 10Be exposure ages, helps to reconstruct the history of glacial fluctuations and past climate changes on the Tibetan Plateau, differences in the timing of glacier advances among different regions. However, different versions of the Cosmic‐Ray‐prOduced NUclide Systematics on Earth (CRONUS‐Earth) online calculator, which calculates and corrects the TCN ages of Quaternary glacial landforms, yield different results. For convenience in establishing contrasts among regions, in this paper, we recalculate 1848 10Be exposure ages from the Tibetan Plateau that were published from 1999 to 2017 using version 2.3 of the CRONUS‐Earth calculator. We also compare the results obtained for 1594 10Be exposure ages using different versions (2.2, 2.3 and 3.0) of the CRONUS‐Earth calculator. The results are as follows. (1) Approximately 97% of the exposure ages are less than 200 ka. A probability density curve of the exposure ages suggests that greater numbers of oscillations emerge during the Holocene, and the peaks correspond to the Little Ice Age, the 8.2 ka and 9.3 ka cold events; the main peak covers the period between 12 and 18 ka. (2) In most areas, the newer versions of the calculator produce older 10Be exposure ages. When different versions of the CRONUS‐Earth calculator are used, approximately 29% of the 10Be exposure ages display maximum differences greater than 10 ka, and the maximum age difference for a single sample is 181.1 ka.

Comparative phylogeography of two sister species of snowcock: impacts of species-specific altitude preference and life history

“…There is a growing understanding that avian evolution in the QTP region has been firmly associated with the orogenetic history of the flanking mountain chains (An et al 2009(An et al , 2015Qu et al 2009;Lei et al 2014). The Tibetan Plateau stretches from the Himalayan Mountains in the south to the Kunlun, Altun and Qilian Mountains in the north and from the Pamirs and the Hindu Kush in the west to the western part of the Qinling Mountain in the east (Zhang et al 2018). However, the investigation on origin and evolutionary history of Tibetan endemic bird species has long been limited to the central plateau region, southern and eastern fringes (Prum et al 2015).…”