Magma Chamber Associated to Deep Faults in Copahue Active Volcanic Complex, South America, Suggested by Magnetotelluric Study
Journal Title: Геофизический журнал - Year 2018, Vol 40, Issue 4
Abstract
Magnetotelluric studies were carried out in 1993 and 2008 inside the caldera of Copahue Volcanic Complex, located in South America, at the border between Chile and Argentina (37°45ʹ S; 71°10.2ʹ W). The main effusive centre of this complex is the Copahue Active Volcano, which constitutes an important geothermal zone. The study of the crust and the investigation of possible magma chambers were the objectives of this survey. Six magnetotelluric soundings were interpreted taking in mind the geologic and tectonic background. Two 2D bimodal modelling along two profiles approximately perpendicular to geological strike were performed. In addition, two magnetovariational studies were made, using two magnetic variometers. Induction (Wiese) vectors were thus estimated for three MT sites. Among the results, the lithosphere in the region is suggested to be 60—66 km thickness, with upper and lower crusts of 8 km and 10 km thickness respectively. A magma chamber is suggested at lower crust with top at 3—8 km depth, with 1 Ωm of resistivity, thus indicating partial-melting or melted-rocks. Data suggest this chamber could be genetically associated with a deep fault system into the caldera. Heat flows of 130—278 mW/m2 were estimated at surface, above magma chambers, using empirical formulas linking depths of thermal conductive layers, in the crust and upper mantle, with heat flows values measured at surface. The estimated heat flows, thus obtained, are rather consistent with heat flows measured in wells drilled into the caldera. Taking into account that magnetotelluric soundings, at present, are not usual in volcanic studies, the present work may give valuable information about this active volcano, (which at present is in yellow alert), mainly because there are people living at about 15 km from the volcano or less in Argentina and Chile. In addition this study is important from geothermal point of view, for the possibility to obtain energy without air contamination.
Authors and Affiliations
E. Borzotta, A. T. Caselli, M. J. Mamani
Keywords
Related Articles
- EP ID EP421028
- DOI 10.24028/gzh.0203-3100.v40i4.2018.140616
- Views 36
- Downloads 0
A thermobaric mechanism for the formation of low velocity zones in the crystalline crust of the northwestern Black Sea shelf: a new type of traps for abiogenic methane
Seismic studies of the NW Black Sea shelf have delineated low-velocity zones (LVZs) in the crystalline crust at depths of 6—16 km. For the first time, this paper presents a novel thermodynamic mechanism for their formati...
The nature of bifocal source of the earthquake and precursors of the blow
On the base of ousting principle and application of the data on location bifocal model of earthquake source is proposed, which includes zones of dilatancy and compaction. The first one corresponds to the recognized set o...
Modeling of regional magnetic field applying spherical functions: theoretical aspect
Observation of geomagnetic field, measurement of its components values and establishment on their base models of geomagnetic field as well as geomagnetic mapping are the main trend of geomagnetic studies. Analytical mode...
Alternatives of «shale scenario» of development of the Russian fuel and energy complex on the basis of the deep oil paradigm of petroleum geology
The condition and ways of the decision of the basic problems of modern petroleum geology in the field of recovery of resources of hydrocarbon and searches of oil and gas fields are discussed. Problems of efficiency, stra...
Analysis of results of interpretation of elastic parameters of solid core of the Earth from the standpoint of current geomechanics
It follows from the basic principles of mechanics of deformable solids relating to the strength, stability and propagation of elastic waves that the inner core of the Earth cannot exist in the form of a spherical structu...