Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1016/j.palaeo.2004.01.020 |
Arid climate 2.5 Ma in the Plio-Pleistocene Valdarno Basin (Northern Apennines, Italy) | |
Ghinassi, M; Magi, M; Sagri, M; Singer, BS | |
通讯作者 | Ghinassi, M |
来源期刊 | PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
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ISSN | 0031-0182 |
EISSN | 1872-616X |
出版年 | 2004 |
卷号 | 207期号:1-2页码:37-57 |
英文摘要 | Distinctive, eolian-dominated sandy deposits 35 m thick exposed along the SW margin of the Plio-Pleistocene Valdarno Basin in the Not-them Apennines, Italy, reflect an unusually arid period in the region. Paleomagnetic investigation and Ar-40/Ar-39 dating of a tephra layer, 10 in above the eolian sand, suggest that the sand was deposited between about 2.7 and 2.4 Ma. This age is coeval with the global climatic deterioration that occurred at the Middle-Upper Pliocene transition. Eolian sediments are represented by cross-bedded sand, rippled sand and horizontal-bedded sand. The alluvial deposits, associated with the eolian sediment, consist of sheet-like beds of coarse sand and erosively based, pebbly sand bodies. Eolian sand, together with fluvial sandy deposits, was formed in the medial-distal portion of an alluvial system, and represents the Rena Bianca Sand Unit. The eolian and alluvial deposits are arranged into sedimentary cycles (2-6 m thick), displaying a wetting-drying-wetting upward trend recording second-order climatic oscillations of ca. 40 ka. Each cycle is enclosed between major bounding surfaces, defined by iron mineral encrustations. These bounding surfaces represent periods of reduced eolian sand accumulation caused by a rising water table. During the 2.5 Ma global cooling, the Valdarno Basin experienced a period of and conditions owing to the influence of cold and dry easterly and northeasterly winds. In contrast, during the Pleistocene, the uplift of the Pratomagno Ridge protected the Valdarno Basin from easterly and northeasterly winds, giving rise to relatively warm and wet conditions, and mitigating the regional and global climatic changes. (C) 2004 Elsevier B.V All rights reserved. |
英文关键词 | Northern Apennines Palcoclimate eolian deposits bounding surfaces sedimentary cycles argon dating |
类型 | Article |
语种 | 英语 |
国家 | Italy ; USA |
收录类别 | SCI-E |
WOS记录号 | WOS:000221484700003 |
WOS关键词 | AEOLIAN SAND SHEETS ; SEQUENCE STRATIGRAPHY ; MEDITERRANEAN SEA ; BOUNDING SURFACES ; ETJO FORMATION ; PLIOCENE ; PRESERVATION ; SEDIMENTS ; DUNE ; SANDSTONE |
WOS类目 | Geography, Physical ; Geosciences, Multidisciplinary ; Paleontology |
WOS研究方向 | Physical Geography ; Geology ; Paleontology |
资源类型 | 期刊论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/147793 |
作者单位 | (1)Univ Siena, Dipartimento Sci Terra, I-53100 Siena, Italy;(2)Univ Florence, Dipartimento Sci Terra, I-50121 Florence, Italy;(3)Univ Wisconsin, Dept Geol & Geophys, Madison, WI 53705 USA |
推荐引用方式 GB/T 7714 | Ghinassi, M,Magi, M,Sagri, M,et al. Arid climate 2.5 Ma in the Plio-Pleistocene Valdarno Basin (Northern Apennines, Italy)[J],2004,207(1-2):37-57. |
APA | Ghinassi, M,Magi, M,Sagri, M,&Singer, BS.(2004).Arid climate 2.5 Ma in the Plio-Pleistocene Valdarno Basin (Northern Apennines, Italy).PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,207(1-2),37-57. |
MLA | Ghinassi, M,et al."Arid climate 2.5 Ma in the Plio-Pleistocene Valdarno Basin (Northern Apennines, Italy)".PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 207.1-2(2004):37-57. |
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