1357 / 2019-08-09 18:00:33

A luminescence chronology of alpine meadow soil based on both Quartz and K-feldspar around Qinghai Lake, northeastern Qinghai-Tibetan Plateau

1、第四纪地质与全球变化 > 专题6：第四纪年代学进展及应用

The extensive alpine meadow soil distributed on the Qinghai-Tibetan Plateau (QTP) plays a core role in local ecological system. However, its formation age and pedogenic process under the varied climatic background in geological history is still unclear. Therefore, it is necessary to carry out a systematic chronological study for alpine meadow soil on the QTP. In this study, a combined luminescence chronology based on both quartz optically stimulated luminescence (OSL) and potassium-rich feldspar (K-feldspar) infrared stimulated luminescence (post-IR IRSL, pIRIR) was firstly employed to determine the age of alpine meadow soil. Meanwhile, accelerator mass spectrometry (AMS) 14C dating method of soil organic matter was used to measure alpine meadow soil’s 14C ages from Xiangpi Mountain (XPSD1 and XPSD2). Sand-sized (63-90 μm) quartz and K-feldspar fractions of the twelve samples from two alpine meadow soil profiles of Riyue Mountain (RYS1 and RYS2) on the northeastern QTP were selected to obtain the equivalent dose (De). The age of the quartz and K-feldspar is in a good agreement. 14C ages are younger than the true age of soils. The alpine meadow soil in the Qinghai Lake (QHL) basin formed and developed mainly during the late Holocene (4-0 ka), the parental material is derived from aeolian dust. The soil development follows the mode of aeolian dust aggradation. Combined with the paleoenvironmental records in QHL, alpine meadow soil might be a product of relatively dry and cold climate.