DOI: 10.1016/j.palaeo.2013.09.030
论文题名: Cool kaolins in Finland
作者: Gilg H.A. ; Hall A.M. ; Ebert K. ; Fallick A.E.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 392 起始页码: 454
语种: 英语
英文关键词: Fennoscandian Shield
; Finland
; Kaolin
; Palaeotemperatures
; Weathering
英文摘要: We use D/H and 18O/16O ratios to explore the age of kaolins on the Fennoscandian Shield. Sub-Cretaceous kaolins in southern Scandinavia have isotopic compositions indicative of weathering under warm mean annual temperatures (MATs) of >15°C. Deep kaolins on the shield surface in Finland previously also have been regarded as products of humid tropical weathering of Mesoproterozoic to Eocene age. New oxygen and hydrogen isotope ratios indicate, however, weathering by cool groundwater under MATs of 13-15°C. Isotope ratios are also not consistent with deep (>1km) burial by cover rocks, indicating that a very old age for the weathering is unlikely. Palaeotemperatures are below Cretaceous MATs, yet substantially above Plio-Pleistocene MATs. Comparisons with palaeotemperatures in N Europe and around the Arctic Ocean indicate that the Finnish kaolins developed on the shield surface in the Palaeogene or, alternatively, Miocene. Deep weathering was selectively developed in highly fractured shield rocks and took place in response to latest Cretaceous and Palaeogene uplift and after stripping of Palaeozoic cover rocks. The cool kaolins in Finland indicate that previous routine attributions of kaolinitic weathering products in the geological record to humid tropical environments should be closely scrutinised. © 2013 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69526
Appears in Collections: 过去全球变化的重建
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作者单位: Lehrstuhl für Ingenieurgeologie, Technische Universität München, Arcisstr. 21, 80333 Munich, Germany; School of Geography and GeoSciences, University of St Andrews, Irvine Building, North Street, St Andrews, KY16 9AL Fife, Scotland, United Kingdom; Department of Physical Geography and Quaternary Geology, Stockholm University, 10691 Stockholm, Sweden; Scottish Universities Environmental Research Centre, East Kilbride, Glasgow G75 0QF, Scotland, United Kingdom
Recommended Citation:
Gilg H.A.,Hall A.M.,Ebert K.,et al. Cool kaolins in Finland[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,392