Paleoenvironmental evolution of Picos de Europa (Spain) during marine isotopic stages 5c to 3 combining glacial reconstruction, cave sedimentology and paleontological findings

[摘要] In glaciated areas, the environmental evolution before MIS 2 is usually poorly constrained mainly due to the later glacial erosion during the global Last Glacial Maximum (LGM). However, in carbonate areas, karst caves can preserve records of pre-LGM paleoenvironment. We studied a cave (1350 m altitude) to establish the paleoenvironmental evolution of a glaciated karst area in Picos de Europa (SW Europe). For this objective, a glacial reconstruction, cave sedimentology analyses, and macro- and micromammal remains are com bined with ten U-Th, OSL and AMS C-14 ages. The paleo-glacial reconstruction indicates glaciers descended down to 810-1040 m of altitude covering an area of 36.18 km(2) in the surroundings of Covadonga Lakes during the glacial local maximum, with the equilibrium line altitude located at 1524 +/- 36 m. The geomorphological study of the cave and the U-Th and OSL dates reveal the presence of three allochthonous alluvial sediment sequences at 132-135, 98-60 and ca. 36 ka. These last two sequences would come from the erosion of fluvioglacial sediments including teeth fragments of Pliomys coronensis (=P. lenki), an unusual species in high areas of NW Spain during the Upper Pleistocene. In addition, remains of chamois (Rupicapra pyrenaica) dated in 37-33 cal ka BP constitutes the oldest evidence of chamois above 800 m asl in the region. All the presented data indicate the development of alpine glacier-free areas covered by fluvioglacial sediments at ca. 1450 m altitude at 98-60 and 37-33 ka, corresponding to glacial retreat stages. (C) 2020 Elsevier Ltd. All rights reserved.

[发布日期] 2020-11-15

[关键词] Karst;Glacial reconstruction;Paleoenvironment;Pliomys coronensis;Rupicapra pyrenaica