Preview

PDF 132920 - Long-l...pdf | Download (7MB) | Preview

Abstract

Long-lived, high-angle fault systems constitute high-permeability zones that can localize the upward flowof hydrothermal fluids and magma throughout the upper crust. Intersections of these types of structures can developcomplex interference patterns, which constitute volumes of damaged rock (networks of small-scale faults and fractures)where permeability may be significantly enhanced. This is relevant for understanding regional-scale structural controlson the emplacement of hydrothermal mineral deposits and volcanic centers, and also on the distribution of areas of activeupper-crustal seismicity. In the high Andes of central Chile, regional-scale geophysical (magnetic, gravimetric, seismic)and structural datasets demonstrate that the architecture of this Andean segment is defined by NW- and NE-strikingfault systems, oblique to the N-S trend of the magmatic arc. Fault systems with the same orientations are well developedin the basement of the Andes. The intersections of conjugate arc-oblique faults constitute the site of emplacement ofNeogene intrusive complexes and giant porphyry Cu-Mo deposits, and define the location of major clusters of upper-crustalearthquakes and active volcanic centers, suggesting that these fault systems are still being reactivated under thecurrent stress regime. A proper identification of one-dimensional, lithospheric-scale high-permeability zones locatedat the intersections of high-angle, arc-transverse fault systems could be the key to understanding problems such as thestructural controls on magmatic and hydrothermal activity and the patterns of upper-crustal seismicity in the high Andesand similar orogenic belts.

Item Type:	Article
Authors/Creators:	Piquer, J and Yanez, G and Rivera, O and Cooke, DR
Keywords:	porphyry, copper, basement fault intersections, magma and hydrothermal fluid flow, central Chile
Journal or Publication Title:	Andean Geology
Publisher:	Servicio Nacional de Geologia y Mineria
ISSN:	0718-7092
DOI / ID Number:	10.5027/andgeoV46n2-3106
Copyright Information:	Copyright 2019 The Authors. Licensed under Creative Commons Attribution 3.0 Unported (CC BY 3.0) https://creativecommons.org/licenses/by/3.0/
Related URLs:	UTAS Profile: Cooke, DR
Item Statistics:	View statistics for this item

Actions (login required)

Item Control Page