QUATERNARY SCIENCE REVIEWS | 卷:211 |
A spatially-restricted Younger Dryas plateau icefield in the Gaick, Scotland: Reconstruction and palaeoclimatic implications | |
Article | |
Chandler, Benjamin M. P.1,2  Boston, Clare M.2  Lukas, Sven3  | |
[1] Queen Mary Univ London, Sch Geog, Mile End Rd, London E1 4NS, England | |
[2] Univ Portsmouth, Dept Geog, Buckingham Bldg,Lion Terrace, Portsmouth PO1 3HE, Hants, England | |
[3] Lund Univ, Dept Geol, Solvegatan 12, S-22362 Lund, Sweden | |
关键词: Plateau icefield; Younger Dryas; Glacier reconstruction; Palaeoclimate; Scotland; | |
DOI : 10.1016/j.quascirev.2019.03.019 | |
来源: Elsevier | |
【 摘 要 】
Considerable research has been conducted in Scotland to reconstruct Younger Dryas glaciers and palaeoclimatic conditions, but our understanding remains incomplete. In this contribution, we examine the Gaick, a dissected plateau that extends over similar to 520 km(2) in the Central Grampians, Scotland. The extent and style of Younger Dryas glaciation in the Gaick has been repeatedly contested, although a model of extensive plateau icefield glaciation has become generally accepted. This is despite well-documented issues with key elements of the plateau icefield reconstruction. We synthesise the results of recent geomorphological mapping in the Gaick and recognise a distinct morphostratigraphic signature in the upper parts of the western catchments. This differs markedly from sediment-landform associations in other parts of the area, and we argue this provides a strong indication of spatially-restricted Younger Dryas (similar to 12.9-11.7 ka) glaciation in the Gaick. Our interpretation is independently supported by glacierisation threshold analysis, which implies that the eastern Gaick was unable to nourish Younger Dryas ice. We therefore contest the accepted paradigm of extensive Younger Dryas glaciation in this area. Based on the geomorphological evidence and glacier surface profile modelling, we reconstruct a similar to 42 km(2) plateau icefield that yields an equilibrium line altitude of 751 +/- 46 m. Using this value, a sea-level precipitation value of 826 +/- 331 mm a(-1) is inferred for the Younger Dryas, which suggests considerably drier conditions than at present. Using recalculated glacier-derived precipitation estimates from Scotland, we present regional climate analysis that corroborates arguments for a strong west-east precipitation gradient across Scotland. (C) 2019 Elsevier Ltd. All rights reserved.
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