Cosmogenic 10 Be surface exposure dating and glacier reconstruction for the Last Glacial Maximum in the Quemuqu Valley, western Nyainqentanglha Mountains, south Tibet

2017 ◽  
Vol 32 (5) ◽  
pp. 639-652 ◽  
Author(s):  
Guocheng Dong ◽  
Xiangke Xu ◽  
Weijian Zhou ◽  
Yunchong Fu ◽  
Li Zhang ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Surface Exposure Dating ◽  
Last Glacial ◽  
Exposure Dating ◽  
Glacier Reconstruction ◽  
The Last Glacial Maximum ◽  
South Tibet ◽  
The Last Glacial

Timing of glacier advances and climate in the High Tatra Mountains (Western Carpathians) during the Last Glacial Maximum

2014 ◽  
Vol 82 (1) ◽  
pp. 1-13 ◽  
Author(s):  
Michał Makos ◽  
Jan Dzierżek ◽  
Jerzy Nitychoruk ◽  
Marek Zreda
Keyword(s):  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Tatra Mountains ◽  
Last Glacial ◽  
Exposure Dating ◽  
Temperature And Precipitation ◽  
Southern Side ◽  
The Last Glacial Maximum ◽  
High Tatra Mountains ◽  
The Last Glacial

AbstractDuring the Last Glacial Maximum (LGM), long valley glaciers developed on the northern and southern sides of the High Tatra Mountains, Poland and Slovakia. Chlorine-36 exposure dating of moraine boulders suggests two major phases of moraine stabilization, at 26–21 ka (LGM I — maximum) and at 18 ka (LGM II). The dates suggest a significantly earlier maximum advance on the southern side of the range. Reconstructing the geometry of four glaciers in the Sucha Woda, Pańszczyca, Mlynicka and Velicka valleys allowed determining their equilibrium-line altitudes (ELAs) at 1460, 1460, 1650 and 1700 m asl, respectively. Based on a positive degree-day model, the mass balance and climatic parameter anomaly (temperature and precipitation) has been constrained for LGM I advance. Modeling results indicate slightly different conditions between northern and southern slopes. The N–S ELA gradient finds confirmation in slightly higher temperature (at least 1 °C) or lower precipitation (15%) on the south-facing glaciers during LGM I. The precipitation distribution over the High Tatra Mountains indicates potentially different LGM atmospheric circulation than at the present day, with reduced northwesterly inflow and increased southerly and westerly inflows of moist air masses.

scholarly journals Glacial geomorphology and cosmogenic 10Be and 26Al exposure ages in the northern Dufek Massif, Weddell Sea embayment, Antarctica

2012 ◽  
Vol 24 (4) ◽  
pp. 377-394 ◽  
Author(s):  
Dominic A. Hodgson ◽  
Michael J. Bentley ◽  
Christoph Schnabel ◽  
Andreas Cziferszky ◽  
Peter Fretwell ◽  
...  
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Weddell Sea ◽  
Glacial Geomorphology ◽  
Last Glacial ◽  
Exposure Dating ◽  
Exposure Ages ◽  
The Last Glacial Maximum ◽  
The Last Glacial

AbstractWe studied the glacial geomorphology and geochronology of two ice-free valleys in the Dufek Massif (Antarctic Specially Protected Area 119) providing new constraints on past ice sheet thickness in the Weddell Sea embayment. 10Be and 26Al cosmogenic surface exposure dating provided chronological control. Seven glacial stages are proposed. These include an alpine glaciation, with subsequent (mid-Miocene?) over-riding by a warm-based ice sheet. Subsequent advances are marked by a series of minor drift deposits at 760 m altitude at > 1 Ma, followed by at least two later ice sheet advances that are characterized by extensive drift sheet deposition. An advance of plateau ice field outlet glaciers from the south postdated these drift sheets. The most recent advance involved the cold-based expansion of the ice sheet from the north at the Last Glacial Maximum, or earlier, which deposited a series of bouldery moraines during its retreat. This suggests at most a relatively modest expansion of the ice sheet and outlet glaciers dominated by a lateral ice expansion of just 2–3 km and maintaining a thickness similar to that of the northern ice sheet front. These observations are consistent with other reports of modest ice sheet thickening around the Weddell Sea embayment during the Last Glacial Maximum.

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

2021 ◽  
pp. 10-17
Author(s):  
Oguz Turkozan
Keyword(s):  
Middle East ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Testudo Graeca ◽  
Last Glacial ◽  
The Past ◽  
Precipitation Seasonality ◽  
Multiple Refugia ◽  
The Last Glacial Maximum ◽  
The Last Glacial

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.

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