Timing of Holocene Lake Highstand in Jinchang Paleolake from the Northeast Tibetan Plateau Foreland
Timing of Holocene Lake Highstand in Jinchang Paleolake from the Northeast Tibetan Plateau Foreland
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DOI：
10.2478/geochr-2020-0004
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发表时间：
2020-07
期刊：
影响因子：
1.2
通讯作者：
H. Long;Hongyi Cheng;Linhai Yang;Lei Gao;Qian Liu
中科院分区：
文献类型：
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作者：
H. Long;Hongyi Cheng;Linhai Yang;Lei Gao;Qian Liu
摘要中国北方干旱区的湖岸线海滩脊及其沉积物常被用作古环境标志。强大的年代学是至关重要的，利用这些档案的古环境重建和解释。利用石英和钾长石发光测年技术，结合放射性碳测年技术，对青藏高原东北缘金昌古湖周围最高浪成海滩脊进行了年代学研究。一致的石英和钾长石年龄表明，沉积前的发光信号的充分复位的调查沉积物。这两种发光年龄与三个独立的14 C年龄一致，进一步证实了这些发光年龄的鲁棒性。研究结果表明，该海滩脊形成于8.5-6.9 ka，表明该地区存在一个明显的湖泊高位期，这一点在附近的其他湖泊中也已得到证实。这种高水位事件可能暗示了区域湿度条件的增加，这可能是由亚洲夏季风降水增加引起的。
Abstract Lake shoreline beach ridges and their sediments have often been investigated as paleoenvironmental indicators in arid northern China. Robust chronology is crucial to utilize this archive for paleoenvironmental reconstruction and interpretation. In this study, we reported a robust chronology for the highest wave-built beach ridge around Jinchang paleolake at the northeast (NE) margin of the Tibetan Plateau, using a combined quartz and K-feldspar luminescence dating technique, together with radiocarbon dating. The consistent quartz and K-feldspar ages suggested the sufficient reset of luminescence signals before deposition for the investigated sediments. Both kinds of luminescence ages were in agreement with three independent 14C ages, further corroborating the robustness of these obtained luminescence ages. Our results demonstrated that the investigated beach ridge was formed around 8.5–6.9 ka, suggesting a distinct period of lake highstand which has been identified in other lakes nearby. This highstand event may implicate an increased regional moisture condition, which is likely caused by the increased Asian summer monsoon precipitation.