Eugenio E Veloso

Servicio Nacional de Geologia y Mineria SERNAGEOMIN · Departamento de Geología Regional Programa de Geología y Geofísica Marina

Geothermal exploration in the Central Andean Volcanic Zone (CAVZ) focuses on heat capacities of known geothermal systems, yet the role of faults, veins, fractures and folds on the evolution and migration of fluids is far from complete. Here, we present a compilation of He and Sr isotope data and newly generated structural maps to examine if particu...

The Chile Triple Junction, where the hot active spreading centre of the Chile Rise system subducts beneath the South American plate, offers a unique opportunity to understand the influence of the anomalous thermal regime on an otherwise cold continental margin. Integrated analysis of various geophysical and geological datasets, such as bathymetry,...

Fiber-optic distributed temperature sensing (DTS) has been widely used since the end of the 20th century, with various industrial, Earth sciences, and research applications. To obtain precise thermal measurements, it is important to extend the currently available DTS calibration methods, considering that environmental and deployment factors can str...

The subduction of an active spreading center generates a clear signature in the temporal evolution of subduction zones. It disrupts the typical arc‐type magmatism and intraplate seismicity, enhances the emplacement of backarc plateau lava and profoundly change the tectonics and topographic relief. These distinct observations are commonly linked to...

Crustal deformation in transpressive tectonic settings is partitioned across fault‐bounded tectonic blocks whose borders may represent ideal loci for enhanced rock exhumation. Field and petrographic analysis, geothermobarometry, zircon U‐Pb geochronology, and zircon and apatite (U‐Th)/He thermochronology were applied to intrusive and metamorphic ro...

The flow structure of a brittle crustal volume is defined by the multi-scale geometric and hydraulic properties of its fracture meshes. The length density distribution n(L,l) and the transmissivity distribution K(L,l) control the hydrologic scaling, where l is fracture length and L is the system size. The flow structure might display at most three...

This paper intends to validate the application of magnetic techniques, particularly magnetic susceptibility, as sampling tools on a copper tailings terrace, by correlating them analytically. Magnetic susceptibility was measured in both the field and laboratory. Data obtained allowed for designing spatial magnetic susceptibility distribution maps, s...

In this work, we present an update for the conceptual model of the El Tatio-La Torta geothermal system, one of the most studied geothermal fields in the Central Andes of South America. Using the structural model reported by Veloso et al. (2019) for northern Chile, the conceptual model proposes a reservoir architecture and heat transfer modes at dif...

Fracture opening at low differential stress controls maximum sustainable fluid pressure (λ) within cohesive brittle crust. Standard Andersonian stress states occur when two conditions are met: (1) one of the principal stresses σ1≥σ2≥σ3 is vertical, and (2) failure occurs at optimal orientations so that stress tensor shape ratio ϕ=(σ2-σ3)/(σ1- σ3) i...

(Free download https://authors.elsevier.com/c/1aZ9vcTGy27qj) The Fe-Cu Dominga deposit (2082 Mt at 23% Fe, 0.07% Cu), located in the Coastal Cordillera of northern Chile, is hosted by volcanic rocks of the Punta del Cobre Formation (131.5±1.5 Ma zircon U-Pb) and into subvolcanic units (Dioritic Complex, 131.6±1.0 Ma zircon U-Pb). The Fe-Cu minerali...

Cerro Pabellón is a hidden high-enthalpy geothermal system (reservoir temperature up to 250 °C) located in the Pampa Apacheta (northern Chile), where the first geothermal power plant in South America is currently operating. A fumarolic field, located on the summit of Apacheta Volcano, about 3.5 km W of Pampa Apacheta, is the only evidence of the pr...

Cerro Pabellón, the first geothermal power plant in South America starting industrial operations (48 MWe) at the end of 2017, is placed over a high enthalpy (T>200°C) geothermal field, located in Pampa Apacheta, Northern Chile. From XRD and SEM-EDX mineralogical analyses on the cuttings of a production well and on the drill core of an exploratory w...

La Zona Volcánica Central Andina de Chile reúne los elementos para el desarrollo de sistemas geotérmicos. No obstante, en el Norte de Chile estos sistemas potenciales están poco estudiados. Entonces, como parte de un estudio geológico regional y con el objetivo de localizar zonas de descarga del sistema hidrotermal del Campo Geotérmico Licancura, s...

Abstract: Recent (<26 Ma) Central Andean volcanism in northern Chile (17º40’-27º10’S) is mainly represented by eruption of large-scale stratovolcanoes. The Altiplano-Puna volcanic complex (APVC; 21°-24°S), a volcano-tectonic province within the Central Andes, is characterized by presence of both crystal-rich huge dacite-rhyolite ignimbrite sheets a...

Oblique subduction between the Nazca and South American plates produces the Southern Volcanic Zone (33-46°S) (SVZ), an active tectono-magmatic-hydrothermal setting. Tectonics of the SVZ is controlled by the Liquiñe-Ofqui Fault System (LOFS) and the Andean Transverse Faults (ATF). The LOFS is an active intra-arc 1200-km-long fault system, with dextr...

Fault zones can control the location, emplacement, and evolution of economic mineral deposits and geothermal systems by acting as barriers and/or conduits to crustal fluid flow (e.g. magma, gas, oil, hydro-geothermal and groundwater). The nature of the fault control permeability is critical in the case of fluid flow into low porosity/permeability c...

The Dominga district in northern Chile (2082 Mt at 23.3 % Fe, 0.07 % Cu) shows a spatial and genetic affinity among distinctive structural elements and Fe–Cu-rich paragenetic mineral assemblages. Deep seated, NE-to-E striking structural elements form a right-lateral duplex-like structural system (early structural system, ESS) that cuts a regionally...

In this study, we examine the fracture network of the Tolhuaca geothermal system located in the Southern Andean volcanic zone that may have acted as a pathway for migration and ascent of deep-seated fluids under the far/local stress field conditions of the area. We measured the orientation, slip-data and mineralogical content of faults and veins re...

Poster presented at the AGU Fall Meeting 2016, San Francisco, USA.

Geothermal exploration in northern Chile is on a developing stage; few studies have dealt with the link between structural elements (i.e. faults, fault-veins and veins), increased heat and fluid flow, and mineral alteration patterns in the development of geothermal fields. In the Licancura area, undergoing a general compression arising from the pla...

Identification of surface hydrothermal mineralogy using Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) imagery is one of the first steps to define potential areas for geothermal exploration; being especially relevant in areas of difficult access (e.g. high-altitude), where direct sampling is logistically complicated and time...

In continental margins, large-scale, strike-slip fault-systems resulted from oblique subduction commonly exhibit a complex pattern of faulting where major faults define the inland boundary of tectonic slivers that can be detached from the margin. In turn, subsidiary faults bound and define internal tectonic blocks within the sliver which are expect...

Abstract In this study, magnetic BaTiO3:Co (BT:Co) nanoparticles prepared using a combined sol–gel-hydrothermal technique were dispersed in a chitosan/Pluronic F-127 solution (QO/Pl) to obtained a nanocomposite hybrid films. Nanoparticles and hybrid films were characterized by X-ray powder diffraction, Fourier transform infrared (FTIR) spectroscopy...

Las distintas asociaciones paragenéticas ricas en minerales de Fe y de Fe-Cu descritas en el depósito y distrito de Dominga (ca. 70 km al norte de La Serena) están espacial y genéticamente relacionadas con una serie de elementos estructurales particulares. A diferencia de otros depósitos de la Franja Ferrífera Cretácica, evidencias de campo indican...

Circulation of hydrothermal solutions through the host rocks of ore bodies generates important mineralogical changes and, consequently, the original magnetic properties of these rocks could be strongly modified. In the Escondida porphyry copper deposit, each lithological-alteration rock unit shows highly distinctive magnetic properties; potassic an...

Integrated Ocean Drilling Program (IODP) Hole 1256D successfully sampled a complete section of an intact oceanic crustal sheeted-dike complex (SDC) (from 1061 to 1320 meters below seafloor; mbsf) on a 15 Ma-old Cocos Plate. A series of rock magnetic measurements were carried out to understand the magmatic processes that accreted this end-member, su...

Fluid–rock interaction related to the circulation of hydrothermal fluids can strongly modify the physicochemical properties of wall rocks in porphyry Cu deposits. These processes can also produce compositional and textural changes in ferromagnetic minerals, which can be quantified using magnetic methods. In the Escondida porphyry Cu deposit of nort...

Reorientation of mesoscopic faults, veins and fractures recovered from drilling is critical to construct reliable structural models that can account for their architecture and deformation regime. However, oriented cores are expensive and time consuming to drill. Some techniques achieve reorientation by introducing tools into the borehole. Problems...

Magnetic proxies obtained from fine-grain sediments have been used to unravel climatic and environmental settings (Evans and Heller, 2003), yet similar studies from coarse-grain sediments lack. We present magnetic and mineralogical measurements of 115 samples collected on four coarse-grained Neogene paleosol profiles (gyspi-, gypsi/verti-, calci-so...

Magnetic parameters obtained from fine-grain sedimentary deposits, such as loess and marine sediments, have helped to obtain information about the concentration, composition and grain-size of magnetic minerals (e.g. Evans and Heller, 2003). Such information when combine indirectly reflects changes of sediment source and/or diagenetic and authigenic...

Thesis (Ph. D. in Science)--University of Tsukuba, (A), no. 3864, 2005.11.30 Includes bibliographical references http://www.tulips.tsukuba.ac.jp/limedio/dlam/B25/B2599545/1.pdf

Uranium-thorium (U-Th) isotope compositions of whole rocks, groundmasses and minerals from mafic to intermediate Andean arc magmas were determined to assess the influence of crustal stress on rates of pre-eruptive crystallization and the significance of crystal uptake. Volcanoes investigated include Lascar in the central Andes, situated in a compre...

Fault development models are crucial to predict geometry and distribution of fractures at all scales. We present here structures related to the development of the Bolfín Fault in the Atacama Fault System (AFS), covering a range of scales of 7 orders of magnitude. The AFS is a 1000 km-long trench-parallel fault system located in the Andean Forearc....

The nature of crustal deformation in active arcs and the feedback mechanisms between tectonics and magma transport constitute fundamental problems in the understanding of volcanic systems. Additionally, for geothermal energy exploration, a better understanding of how crustal architecture and stress field controls fluid ascent and heat transfer from...

Chile ridge subducts underneath South American plate at latitude 46S, forming a ridge-trench-trench type triple junction that migrated to the north along the Pacific coast. At ~6 Ma, a short segment of the Chile ridge system collided and subducted in the south of the present triple junction. This ridge subduction event resulted in emplacement of th...

In this contribution we examine the relationship between active compression and construction of Pleistocene volcanoes in the present-day magmatic arc of the central Andes (23°S-24°S). Deformation produced several N-S striking, ˜40 km long subparallel ridges. These ridges formed by folding of Pliocene ignimbrites and upper Pliocene and Pleistocene l...

Fault development models are very important to predict geometry and distribution of fractures at all scales. However, models based on structures from microns to km are relatively scarce due to the lack of well-exposed structures. We present structures related to the development of the Bolfín fault in the Atacama Fault System (AFS), covering a scale...

Tectonic evolution of crustal slivers generated during oblique subduction involves a series of translations and rotations. Slivers are defined by large-scale strike-slip faults, whereas internal blocks are by the faulting pattern related to the fault system. Translations and rotations are then likely to accommodate the internal deformation caused b...

The Taitao granites are distributed around the Late Miocene Taitao ophiolite (5.66 ± 0.33 Ma to 5.19 ± 0.15 Ma) exposed at the western tip of the Taitao peninsula, southern Chile, ~ 50 km southeast from the present day Chile triple junction. In this paper, we report sensitive high mass-resolution ion microprobe (SHRIMP) U–Pb ages for the Taitao gra...

The repeated north and southward migration of the Chile Triple junction, offshore the Península de Taitao, is expected to have imposed contrasting stress fields in the forearc for the last 6 Ma because of changes in convergence direction and rate of subducting plates. NNW-SSE to E-W and minor NE-SW striking brittle faults developed in the plutonic...

The repeated north and southward migration of the Chile Triple junction, offshore the Península de Taitao, is expected to have imposed contrasting stress fi elds in the forearc for the last 6 Ma because of changes in convergence direction and rate of subducting plates. NNW-SSE to E-W and minor NE-SW striking brittle faults developed in the plutonic...

Determination of paleocurrent directions is a robust approach to establish the mechanism of sediment transport and of deposition. However, in tectonically controlled (or affected) basins where rotations are suspected, it is of critical importance to correct previously calculated paleocurrent directions to establish the original (pre-tectonic) trans...

Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismi...

Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic l...

One view of seafloor spreading is that mechanical deformation is not significant at high spreading rates. With recovery of up to 37%, and the vertical axis known for many pieces, shipboard visual core descriptions from Hole 1256D provide an opportunity to evaluate the significance of deformational structures in EPR-, superfast- (~220 mm-yr) spread...

Abstract The < 6 Ma young Taitao ophiolite, exposed at the westernmost promontory of the Taitao Peninsula, is located approximately 40 km southeast of the Chile triple junction and consists of a complete sequence of oceanic lithosphere. Systematic sampling for paleomagnetic study was performed to understand the complex obduction processes of the op...