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Along-strike segmentation of the Abanico Basin, central Chile: new chronological, geochemical and structural constraints


Piquer, J and Hollings, P and Rivera, O and Cooke, DR and Baker, M and Testa, F, Along-strike segmentation of the Abanico Basin, central Chile: new chronological, geochemical and structural constraints, Lithos, 268-271 pp. 174-197. ISSN 0024-4937 (2017) [Refereed Article]

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Copyright 2016 Elsevier B.V. ę <year>. This manuscript version is made available under the Creative Commons Attribution NonCommercial NoDerivatives (CC-BY-NC-ND) 4.0 license

DOI: doi:10.1016/j.lithos.2016.10.025


The Andes of central Chile are composed mostly of Cenozoic volcanic rocks, erupted during the opening and subsequent inversion of the intra-arc volcano-tectonic Abanico Basin. Until recently, the internal segmentation of this inverted basin was poorly understood. Based on a combination of U-Pb geochronology, (U-Th)/He thermochronology, whole rock geochemistry and structural data, we propose that the Abanico Basin can be divided into two main segments, separated by the NW-striking Piuquencillo fault and conjugate, NE-striking faults. Stratigraphic units defined in the northern segment (Abanico and Farellones formations) cannot be correlated with the rocks of the southern segment (Coya-Machali Formation and Teniente Volcanic Complex) in terms of lithofacies, depositional ages and geochemistry. The northern and southern segments also show temporal differences in their tectonic evolution. An early deformation event beginning at ~22áMa affected only the northern segment and is associated with the formation of progressive unconformities between the Abanico and Farellones formations, and also with crustal thickening as reflected in the geochemistry of the Farellones Formation. A second stage of crustal thickening and exhumation began at ~12áMa, as suggested by a sharp increase of the La/Yb ratios in the northern segment. In the southern segment, this event is reflected by only a moderate increase of La/Yb ratios, and by the transition between the Coya-Machali Formation and the Teniente Volcanic Complex. Finally, a third stage of exhumation and crustal thickening beginning at ~7áMa affected both the northern and southern segments. This last stage was the main exhumation event affecting the rocks of the Andes of central Chile, and is recorded in the geochemistry of igneous rocks by a sharp increase in the La/Yb ratios in the southern segment.

Item Details

Item Type:Refereed Article
Keywords:Andes, Central Chile, Abanico Basin, geochronology, thermochronology, geochemical evolution
Research Division:Earth Sciences
Research Group:Geology
Research Field:Geochronology
Objective Division:Mineral Resources (Excl. Energy Resources)
Objective Group:Mineral exploration
Objective Field:Copper ore exploration
UTAS Author:Piquer, J (Mr Jose Piquer Romo)
UTAS Author:Cooke, DR (Professor David Cooke)
UTAS Author:Baker, M (Dr Michael Baker)
UTAS Author:Testa, F (Dr Francisco Testa)
ID Code:113948
Year Published:2017
Web of Science® Times Cited:30
Deposited By:CODES ARC
Deposited On:2017-01-30
Last Modified:2022-07-11
Downloads:7 View Download Statistics

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