Three-Dimensional Electrical Resistivity Modeling to Elucidate the Crustal Magma Supply System Beneath Aso Caldera, Japan

2018 ◽  
Author(s):  
M. Hata ◽  
N. Matsushima ◽  
S. Takakura ◽  
M. Utsugi ◽  
T. Hashimoto ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Supply System ◽  
Magma Supply ◽  
Aso Caldera ◽  
Crustal Magma ◽  
Resistivity Modeling

scholarly journals Crustal magma pathway beneath Aso caldera inferred from three-dimensional electrical resistivity structure

2016 ◽  
Vol 43 (20) ◽  
pp. 10,720-10,727 ◽  
Author(s):  
Maki Hata ◽  
Shinichi Takakura ◽  
Nobuo Matsushima ◽  
Takeshi Hashimoto ◽  
Mitsuru Utsugi
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Resistivity Structure ◽  
Aso Caldera ◽  
Crustal Magma

scholarly journals Magnetotelluric study in the Los Lagos Region (Chile) to investigate volcano-tectonic processes in the Southern Andes

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Maria Jose Segovia ◽  
Daniel Diaz ◽  
Katarzyna Slezak ◽  
Felipe Zuñiga
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Phase Changes ◽  
Fault System ◽  
Electrical Anisotropy ◽  
Mountain Range ◽  
Southern Andes ◽  
Nazca Plate ◽  
First Results ◽  
Dimensional Parameters

AbstractTo analyze the process of subduction of the Nazca and South American plates in the area of the Southern Andes, and its relationship with the tectonic and volcanic regime of the place, magnetotelluric measurements were made through a transversal profile of the Chilean continental margin. The data-processing stage included the analysis of dimensional parameters, which as first results showed a three-dimensional environment for periods less than 1 s and two-dimensional for periods greater than 10 s. In addition, through the geomagnetic transfer function (tipper), the presence of structural electrical anisotropy was identified in the data. After the dimensional analysis, a deep electrical resistivity image was obtained by inverting a 2D and a 3D model. Surface conductive anomalies were obtained beneath the central depression related to the early dehydration of the slab and the serpentinization process of the mantle that coincides in location with a discontinuity in the electrical resistivity of a regional body that we identified as the Nazca plate. A shallow conductive body was located around the Calbuco volcano and was correlated with a magmatic chamber or reservoir which in turn appears to be connected to the Liquiñe Ofqui fault system and the Andean Transverse Fault system. In addition to the serpentinization process, when the oceanic crust reaches a depth of 80–100 km, the ascending fluids produced by the dehydration and phase changes of the minerals present in the oceanic plate produce basaltic melts in the wedge of the subcontinental mantle that give rise to an eclogitization process and this explains a large conductivity anomaly present beneath the main mountain range.

scholarly journals Crustal architecture of a metallogenic belt and ophiolite belt: implications for mineral genesis and emplacement from 3-D electrical resistivity models (Bayankhongor area, Mongolia)

2021 ◽  
Vol 73 (1) ◽  
Author(s):  
Matthew J. Comeau ◽  
Michael Becken ◽  
Alexey V. Kuvshinov ◽  
Sodnomsambuu Demberel
Keyword(s):  
Electrical Resistivity ◽  
Crustal Structure ◽  
Three Dimensional ◽  
Suture Zone ◽  
Fault System ◽  
Magnetotelluric Data ◽  
Low Resistivity ◽  
Ophiolite Belt ◽  
Geological Processes ◽  
Metallogenic Belt

AbstractCrustal architecture strongly influences the development and emplacement of mineral zones. In this study, we image the crustal structure beneath a metallogenic belt and its surroundings in the Bayankhongor area of central Mongolia. In this region, an ophiolite belt marks the location of an ancient suture zone, which is presently associated with a reactivated fault system. Nearby, metamorphic and volcanic belts host important mineralization zones and constitute a significant metallogenic belt that includes sources of copper and gold. However, the crustal structure of these features, and their relationships, are poorly studied. We analyze magnetotelluric data acquired across this region and generate three-dimensional electrical resistivity models of the crustal structure, which is found to be locally highly heterogeneous. Because the upper crust (< 25 km) is found to be generally highly resistive (> 1000 Ωm), low-resistivity (< 50 Ωm) features are conspicuous. Anomalous low-resistivity zones are congruent with the suture zone, and ophiolite belt, which is revealed to be a major crustal-scale feature. Furthermore, broadening low-resistivity zones located down-dip from the suture zone suggest that the narrow deformation zone observed at the surface transforms to a wide area in the deeper crust. Other low-resistivity anomalies are spatially associated with the surface expressions of known mineralization zones; thus, their links to deeper crustal structures are imaged. Considering the available evidence, we determine that, in both cases, the low resistivity can be explained by hydrothermal alteration along fossil fluid pathways. This illustrates the pivotal role that crustal fluids play in diverse geological processes, and highlights their inherent link in a unified system, which has implications for models of mineral genesis and emplacement. The results demonstrate that the crustal architecture—including the major crustal boundary—acts as a first‐order control on the location of the metallogenic belt.

Lineaments Revisited

SEG Discovery ◽  
2000 ◽  
pp. 1-20
Author(s):  
JEREMY P. RICHARDS
Keyword(s):  
Large Scale ◽  
Mineral Exploration ◽  
Porphyry Copper ◽  
Regional Scale ◽  
Tectonic Events ◽  
Magma Reservoirs ◽  
Magma Supply ◽  
Magmatic History ◽  
Lithospheric Stress ◽  
Crustal Magma

ABSTRACT Large-scale crustal lineaments are recognized as corridors (up to 30 km wide) of aligned geological, structural, geomorphological, or geophysical features that are distinct from regional geological trends such as outcrop traces. They are commonly difficult to observe on the ground, the scale of the features and their interrelationships being too large to map except at a regional scale. They are therefore most easily identified from satellite imagery and geophysical (gravity, magnetic) maps. Lineaments are believed to be the surface expressions of ancient, deep-crustal or trans-lithospheric structures, which periodically have been reactivated as planes of weakness during subsequent tectonic events. These planes of weakness, and in particular their intersections, may provide high-permeability channels for ascent of deeply derived magmas and fluids. Optimum conditions for magma penetration are provided when these structures are placed under tension or transtension. In regions of subduction-related magmatism, porphyry copper and related deposits may be generated along these lineaments because the structures serve to focus the ascent of relatively evolved magmas and fluid distillates from deep-crustal magma reservoirs. However, lineament intersections can only focus such activity where a magma supply exists, and when lithospheric stress conditions permit. A comprehensive understanding of regional tectono-magmatic history is therefore required to interpret lineament maps in terms of their prospectivity for mineral exploration.

Unusual Bonding in Ternary Nitrides: Preparation, Structure and Properties of Ce2MnN3.

1998 ◽  
Vol 53 (1) ◽  
pp. 63-74 ◽  
Author(s):  
Rainer Niewa ◽  
Grigori V. Vajenine ◽  
Francis J. DiSalvo ◽  
Haihua Luob ◽  
William B. Yelon
Keyword(s):  
Electrical Resistivity ◽  
Three Dimensional ◽  
Structure And Properties ◽  
Electronic Effects ◽  
Nitrogen Gas ◽  
Metallic Behavior ◽  
Band Structure Calculations ◽  
Dimensional Network ◽  
Square Planar ◽  
Structure Calculations

Ce2MnN3 was prepared by reaction of cerium nitride and manganese with nitrogen gas at 900 °C. It crystallizes isotypic to AC2MN3 (Ac = U, Th; M = Cr, Mn) and Ce2CrN3, space group Immm (No. 71), a = 3.74994(6) Å, b = 3.44450(6) Å and c = 12.4601(2) Å. The manganese atoms are coordinated in a nearly square planar fashion by four nitrogen atoms. These corner-connected MnN4 units form infinite 1∞[MnN2N2/2] chains, which run parallel to each other along the crystallographic a-axis, forming the motif of hexagonal rod packing. Cerium atoms connect the chains into a three-dimensional network. The results of measurements of the magnetic susceptibility, as well as of the electrical resistivity suggest metallic behavior. Electronic effects leading to shorter bonds between manganese and bridging nitrogen atoms than between manganese and terminal nitrogen atoms in the 1∞[MnN2N2/2] chains were investigated through extended Hückel and LMTO band structure calculations. Issues pertaining to stability of this and some other nitridometallate structures are discussed.

Sign in / Sign up

Export Citation Format

Share Document