Knowledge Resource Center for Ecological Environment in Arid Area
DOI | 10.1016/j.tecto.2007.10.013 |
Sedimentation and preservation of the Miocene Atacama Gravels in the Pedernales-Chanaral Area, Northern Chile: Climatic or tectonic control? | |
Nalpas, T.1; Dabard, M. -P.1; Ruffet, G.1; Vernon, A.1; Mpodozis, C.2; Loi, A.3; Herail, G.4,5 | |
通讯作者 | Nalpas, T. |
会议名称 | 6th International Symposium on Andean Geodynamics (ISAG) |
会议日期 | SEP 12-14, 2005 |
会议地点 | Barcelona, SPAIN |
英文摘要 | In recent years, longitudinal changes on the thin/thick-skinned tectonic styles of the Central Andes has been intensively discussed while other studies have considered the role of mass transfers on the unloading of the orogen, and on the stress regime along the plate interface arising from changes on the volume of sediment arriving into the Peru-Chile trench. The search for paleo-climate records is therefore crucial for our understanding of the history of the Central Andes. In this paper, we focus on the Atacama Gravels, an extensive blanket of Miocene continental deposits filling a Neogene paleo-valley system along the southern Atacama Desert in northern Chile. An east-west transect, between Pedernales and Chanaral (26 degrees 30'S), enabled us to carry out a sedimentological and tectonic study of the Atacama Gravels, based on logging and field observations along the Rio Salado canyon. New (39)Ar-(40)Ar ages obtained on intercalated and overlying ignimbrites date the beginning of the Atacama Gravels sedimentation at around the Oligocene-Miocene boundary and cessation of sedimentation in the Late Miocene. Thirteen lithofacies, included within five facies associations (A1 to A5) were identified. Depositional environments vary from proximal alluvial fan (A1, A2) in the Precordillera through ephemeral fluvial (A3, A4) to distal playa lake (A5) in the Coastal Cordillera. No evidences of synsedimentary deformation have been found, showing that the change from sediment removal to sediment preservation cannot be explained by tectonic causes. and climate change appears to be the dominant controlling factor of sediment preservation. A progressive change from semi-arid towards hyper-arid climatic conditions during the Miocene, led to a reduction on the transport capacity of the fluvial system and sediment preservation along the paleo-valley system formed during the Oligocene. (c) 2008 Elsevier B.V. All rights reserved. |
英文关键词 | Atacama Gravels Andes Depositional environments Climate Deformation (39)Ar-(40)Ar dating |
来源出版物 | TECTONOPHYSICS |
ISSN | 0040-1951 |
出版年 | 2008 |
卷号 | 459 |
期号 | 1-4 |
页码 | 161-173 |
出版者 | ELSEVIER SCIENCE BV |
类型 | Article;Proceedings Paper |
语种 | 英语 |
国家 | France;Chile;Italy |
收录类别 | SCI-E ; CPCI-S |
WOS记录号 | WOS:000261369300011 |
WOS关键词 | AR-40-AR-39 LASER PROBE ; FAN-DELTA SYSTEM ; CENTRAL ANDES ; ALLUVIAL FANS ; PUNA PLATEAU ; EXCESS ARGON ; COASTAL CORDILLERA ; FLOW DEPOSITS ; WESTERN ALPS ; LA-ESCONDIDA |
WOS类目 | Geochemistry & Geophysics |
WOS研究方向 | Geochemistry & Geophysics |
资源类型 | 会议论文 |
条目标识符 | http://119.78.100.177/qdio/handle/2XILL650/297443 |
作者单位 | 1.Univ Rennes 1, UMR 6118, F-35042 Rennes, France; 2.ENAP SIPETROL, Las Condes, Santiago Chile, Chile; 3.Univ Cagliari, Dipartimento Sci Terra, I-09127 Cagliari, Italy; 4.LMTG, IRD, F-31400 Toulouse, France; 5.Univ Chile, Dpto Geol, Santiago, Chile |
推荐引用方式 GB/T 7714 | Nalpas, T.,Dabard, M. -P.,Ruffet, G.,et al. Sedimentation and preservation of the Miocene Atacama Gravels in the Pedernales-Chanaral Area, Northern Chile: Climatic or tectonic control?[C]:ELSEVIER SCIENCE BV,2008:161-173. |
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