气候变化领域集成服务门户(CCPortal): Postglacial evolution of a formerly glaciated valley: Reconstructing sediment supply, fan building, and confluence effects at the millennial time scale

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DOI	10.1130/B31924.1
	Postglacial evolution of a formerly glaciated valley: Reconstructing sediment supply, fan building, and confluence effects at the millennial time scale
	Brardinoni F.; Picotti V.; Maraio S.; Bruno P.P.; Cucato M.; Morelli C.; Mair V.
发表日期	2018
ISSN	167606
起始页码	1457
结束页码	1473
卷号	130 期号:2021-09-10
英文摘要	We reconstruct the post-Last Glacial Maximum (LGM) evolution of the upper Adige River floodplain, Eastern Italian Alps. In particular, we are interested in constraining the time scales associated with fan building and understanding how the relevant sediment supply at tributary confluences has interacted with the Adige River to form the present landscape configuration. By combining high-resolution seismic imaging with drillhole data and radiocarbon dating, we show (i) that ~80% of the valley fill was deposited in post-LGM times, (ii) that sediment evacuation from tributaries began with local deglaciation at the end of the Younger Dryas; and (iii) that tributary basin aspect and size, by controlling the local pattern of deglaciation, may have delayed fan building by up to two millennia. Debris-flow sediment supply from the Gadria-Strimm system drove the evolution of this valley segment between 12 and 6.25 k.y. B.P., first deflecting, then damming the course of the Adige River, forming a lake, and affecting the shape and size of the neighboring fans. Our data show an anisotropic development of the Gadria fan, with growth focused on the central and eastern portion of the fan between 10 and 8.5 k.y. B.P., followed by gradual lateral shifting toward west for about the next two millennia. The estimated sediment yield associated with the fan formation describes a debris flow-driven paraglacial sedimentary wave that conforms to the conceptual model originally proposed by Church and Ryder (1972), but never tested before in upland basins with empirical data. The wave lasted for ~4 k.y. and around 9 k.y. B.P. peaked at ~390,000 m3yr-1. At the valley profile scale, results suggest that similar fans functioned as effective sediment traps, which prevented, and still limit, fluvial reworking and valley floor incision. We argue that these geomorphic barriers, which have enhanced fragmentation of the valley long profile, with knickpoints located at major tributary fans, have delayed postglacial landscape recovery until today. © 2018 Geological Society of America.
语种	英语
来源期刊	Bulletin of the Geological Society of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/185082
作者单位	Department of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy; Department of Earth Sciences, ETH Zürich, Zürich, Switzerland; Centro di GeoTecnologie, University of Siena, San Giovanni Valdarno, Italy; The Petroleum Institute, Department of Petroleum Geosciences, Abu Dhabi, United Arab Emirates; Provincia Autonoma di Bolzano, Ufficio Geologia e Prove Materiali, Cardano, Italy
推荐引用方式 GB/T 7714	Brardinoni F.,Picotti V.,Maraio S.,et al. Postglacial evolution of a formerly glaciated valley: Reconstructing sediment supply, fan building, and confluence effects at the millennial time scale[J],2018,130(2021-09-10).
APA	Brardinoni F..,Picotti V..,Maraio S..,Bruno P.P..,Cucato M..,...&Mair V..(2018).Postglacial evolution of a formerly glaciated valley: Reconstructing sediment supply, fan building, and confluence effects at the millennial time scale.Bulletin of the Geological Society of America,130(2021-09-10).
MLA	Brardinoni F.,et al."Postglacial evolution of a formerly glaciated valley: Reconstructing sediment supply, fan building, and confluence effects at the millennial time scale".Bulletin of the Geological Society of America 130.2021-09-10(2018).