The disappearance of glaciers in the Tien Shan Mountains in Central Asia at the end of Pleistocene

Takeuchi, Nozomu; Fujita, Koji; Aizen, Vladimir; Narama, Chiyuki; Yokoyama, Yūsuke; Okamoto, S.; Kinoshita, Naoki; Kubota, Jumpei

doi:10.1016/j.quascirev.2014.09.006

Cited by 45 publications

(58 citation statements)

References 33 publications

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“…1). Our estimated ages at the ice-bedrock interface (8.3± 6.2 3.6 ka BP for the Chongce 216.6 m Core 4 and 9.0± 7.9 3.6 ka BP for the Chongce 135.8 m Core 2 respectively, see details in Supplement) are either of Holocene origin or, less likely, originate in the late deglaciation period, similarly to the result of the Grigoriev ice core in the western Tien Shan (Takeuchi et al, 2014). In both cases, the results con- firm the upper constraint of 42 ± 4 ka BP derived from the luminescence age of the basal sediment sample collected from the bottom of the Chongce 216.6 m Core 4 (Zhang et al, 2018).…”

Section: Discussionmentioning

confidence: 82%

“…Borehole temperatures were −2.7 • C at 10 m and −3.9 • C at the ice-bedrock interface. Takeuchi et al (2014) suggested that the bottom age of the Grigoriev ice core coincides with the Younger Dryas cold period (YD, 11.7-12.9 ka BP). However, the oldest 14 C age (12.58 ± 0.10 ka) is obtained from a soil sample collected underneath the glacier, which should be considered an upper constraint for the age of ice at the ice-bedrock interface.…”

Section: The Grigoriev Ice Corementioning

confidence: 99%

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Age ranges of the Tibetan ice cores with emphasis on the Chongce ice cores, western Kunlun Mountains

et al. 2018

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Abstract. An accurate chronology is the essential first step for a sound understanding of ice core records. However, dating ice cores drilled from the high-elevation glaciers is challenging and often problematic, leading to great uncertainties. The Guliya ice core, drilled to the bedrock (308.6 m in length) along the western Kunlun Mountains on the northwestern Tibetan Plateau (TP) and widely used as a benchmark for palaeoclimate research, is believed to reach > 500 ka (thousand years) at its bottom. Meanwhile other Tibetan ice cores (i.e. Dasuopu and East Rongbuk in the Himalayas, Puruogangri in the central TP and Dunde in the north-eastern TP) are mostly of Holocene origin. In this study, we drilled four ice cores into bedrock (216.6, 208.6, 135.8 and 133.8 m in length, respectively) from the Chongce ice cap ∼ 30 km to the Guliya ice core drilling site. We took measurements of 14 C, 210 Pb, tritium and β activity for the ice cores, and used these values in a two-parameter flow model to establish the ice core depth-age relationship. We suggested that the Chongce ice cores might be of Holocene origin, consistent with the other Tibetan ice cores except Guliya. The remarkable discrepancy between the Guliya and all the other Tibetan ice core chronology implies that more effort is necessary to explore multiple dating techniques to confirm the age ranges of the TP glaciers, including those from Chongce and Guliya.

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Section: Discussionmentioning

confidence: 82%

Section: The Grigoriev Ice Corementioning

confidence: 99%

Age ranges of the Tibetan ice cores with emphasis on the Chongce ice cores, western Kunlun Mountains

et al. 2018

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“…The largest improvement was found at Gregorieve (78°E, 42°N), where the correlation improved from 0.26 to 0.38, and the root-mean-square error decreased by about 14%. Takeuchi et al (2014) reported a relatively high borehole temperature of −2.7°C at the site. Because the impact of the diffusion is large at warm sites, the core should be affected by the diffusion; thus, the consideration of the process improved the reproducibility.…”

Section: Ice Coresmentioning

confidence: 95%

Global Evaluation of Proxy System Models for Stable Water Isotopes With Realistic Atmospheric Forcing

Okazaki

Yoshimura

2019

JGR Atmospheres

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Proxy system models (PSMs) are an important bridge between climate simulations and climate records prior to the period where instrumental observations are available. PSMs help to interpret what proxies show and how they record climate. Although previous studies have evaluated PSMs for individual sites, their systematic evaluation on a global scale has not yet been conducted. This study evaluated the performance of PSMs for stable water isotopes in ice cores, corals, and tree‐ring cellulose for the period 1950–2007. Spatial distributions of the mean state were well simulated for all proxy types, albeit with a bias for tree‐ring cellulose. Interannual variability was well simulated for corals and tree‐ring cellulose. These results indicate that the models represent key mechanisms for the proxies. In contrast, the reproducibility of interannual variability in ice cores was markedly lower than that for the other proxies. Although the reproducibility was limited by the atmospheric forcing used to drive the model, the results suggest that the PSM may be missing postdepositional processes, such as sublimation for ice cores on the interannual time scale.

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“…We use a simplified and idealised scenario for the Eastern Tian Shan deglaciation. An ice core in the Kyrgyz Tian Shan shows a more complicated post‐LGM history with glacial advance at the Younger Dryas (Takeuchi et al ., ). A detailed history of deglaciation in each studied catchment could inform the precise timing of sediment evacuation.…”

Section: Pleistocene Climate and Aggradation–incision Cyclesmentioning

confidence: 99%

Lag and mixing during sediment transfer across the Tian Shan piedmont caused by climate‐driven aggradation–incision cycles

et al. 2017

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Transient sediment storage and mixing of deposits of various ages during transport across alluvial piedmonts alters the clastic sedimentary record. We quantify buffering and mixing during cycles of aggradation-incision in the north piedmont of the Eastern Tian Shan. We complement existing chronologic data with 20 new luminescence ages and one cosmogenic radionuclide age of terrace abandonment and alluvial aggradation. Over the last 0.5 Myrs, the piedmont deeply incised and aggraded many times per 100 kyr. Aggradation is driven by an increased flux of glacial sediment accumulated in the high range and flushed onto the piedmont by greater water discharge at stadialinterstadial transitions. After this sediment is evacuated from the high range, the reduced input sediment flux results in fluvial incision of the piedmont as fast as 9 cm/yr and to depths up to 330 m. The timing of incision onset is different in each river and does not directly reflect climate forcing but the necessary time for the evacuation of glacial sediment from the high range. A significant fraction of sediments evacuated from the high range is temporarily stored on the piedmont before a later incision Accepted ArticleThis article is protected by copyright. All rights reserved.phase delivers it to the basin. Coarse sediments arrive in the basin with a lag of at least 7 to 14 kyrs between the first evacuation from the mountain and later basinward transport. The modern output flux of coarse sediments from the piedmont contains a significant amount of recycled material that was deposited on the piedmont as early as the Middle Pleistocene. Variations in temperature and moisture delivered by the Westerlies are the likely cause of repeated aggradation-incision cycles in the north piedmont instead of monsoonal precipitation. The arrival of the gravel front into the proximal basin is delayed relative to the fine-grained load and both are separated by a hiatus. This work shows, based on field observations and data, how sedimentary systems respond to climatic perturbations, and how sediment recycling and mixing can ensue.

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The disappearance of glaciers in the Tien Shan Mountains in Central Asia at the end of Pleistocene

Cited by 45 publications

References 33 publications

Age ranges of the Tibetan ice cores with emphasis on the Chongce ice cores, western Kunlun Mountains

Age ranges of the Tibetan ice cores with emphasis on the Chongce ice cores, western Kunlun Mountains

Global Evaluation of Proxy System Models for Stable Water Isotopes With Realistic Atmospheric Forcing

Lag and mixing during sediment transfer across the Tian Shan piedmont caused by climate‐driven aggradation–incision cycles

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