Scattering Attenuation Images of the Control of Thrusts and Fluid Overpressure on the 2016–2017 Central Italy Seismic Sequence

Deep fluid circulation likely triggered the large extensional events of the 2016–2017 Central Italy seismic sequence. Nevertheless, the connection between fault mechanisms, main crustal-scale thrusts, and the circulation and interaction of fluids with tectonic structures controlling the sequence is still debated. Here, we show that the 3D temporal and spatial mapping of peak delays, proxy of scattering attenuation, detects thrusts and sedimentary structures and their control on fluid overpressure and release. After the mainshocks, scattering attenuation drastically increases across the hanging wall of the Monti Sibillini and Acquasanta thrusts, revealing fracturing and fluid migration. Before the sequence, low-scattering volumes within Triassic formations highlight regions of fluid overpressure, which enhances rock compaction. Our results highlight the control of thrusts and paleogeography on the sequence and hint at the monitoring potential of the technique for the seismic hazard assessment of the Central Apennines and other tectonic regions

Cap rock efficiency of geothermal systems in fold-and-thrust belts:evidence from paleo-thermal and structural analyses in Rosario de La Frontera geothermal area (NW Argentina)

Cap rock characterization of geothermal systems is often neglected despite fracturing may reduce its efficiency and favours fluid migration. We investigated the siliciclastic cap rock of Rosario de La Frontera geothermal system (NW Argentina) in order to assess its quality as a function of fracture patterns and related thermal alteration. Paleothermal investigations (XRD on fine-grained fraction of sediments, organic matter optical analysis and fluid inclusions on veins) and 1D thermal modelling allowed us to distinguish the thermal fingerprint associated to sedimentary burial from that related to fluid migration. The geothermal system is hosted in a Neogene N-S anticline dissected by high angle NNW- and ENE-striking faults. Its cap rock can be grouped into two quality categories: ● rocks acting as good insulators deformed by NNW–SSE and E–W shear fractures, NNE-SSW gypsum- and N-S striking calcite-filled veins formed during the initial stage of anticline growth. Maximum paleo-temperatures (<60°C) were experienced during deposition to folding phases. ● rocks acting as bad insulators deformed by NNW-SSE fault planes and NNW- and WNW-striking sets of fractures associated to late transpressive kinematics. Maximum paleo-temperatures higher than about 115°C are linked to fluid migration from the reservoir to surface (with a reservoir top at maximum depths of 2.5 km) along fault damage zones. This multi-method approach turn out to be particularly useful to trace the main pathways of hot fluids and can be applied in blind geothermal systems where either subsurface data are scarce or surface thermal anomalies are lacking

A Dominant Negative ERβ Splice Variant Determines the Effectiveness of Early or Late Estrogen Therapy after Ovariectomy in Rats

The molecular mechanisms for the discrepancy in outcome of initiating estrogen therapy (ET) around peri-menopause or several years after menopause in women are unknown. We hypothesize that the level of expression of a dominant negative estrogen receptor (ER) β variant, ERβ2, may be a key factor determining the effectiveness of ET in post-menopausal women. We tested this hypothesis in ovariectomized nine month-old (an age when irregular estrous cycles occur) female Sprague Dawley rats. Estradiol treatment was initiated either 6 days (Early ET, analogous to 4 months post-menopause in humans), or 180 days (Late ET, analogous to 11 years post-menopause in humans) after ovariectomy. Although ERβ2 expression increased in all OVX rats, neurogenic and neuroprotective responses to estradiol differed in Early and Late ET. Early ET reduced ERβ2 expression in both hippocampus and white blood cells, increased the hippocampal cell proliferation as assessed by Ki-67 expression, and improved mobility in the forced swim test. Late ET resulted in either no or modest effects on these parameters. There was a close correlation between the degree of ERβ2 expression and the preservation of neural effects by ET after OVX in rats, supporting the hypothesis that persistent elevated levels of ERβ2 are a molecular basis for the diminished effectiveness of ET in late post-menopausal women. The correlation between the expression of ERβ2 in circulating white blood cells and brain cells suggests that ERβ2 expression in peripheral blood cells may be an easily accessible marker to predict the effective window for ET in the brain

Fracture Modeling applied to the geothermal system potential reservoir of Rosario de La Frontera (La Candelaria Ridge, NW Argentina)

[No abstract available

Reconstruction of a “Discrete Fracture Network” in the geothermal reservoir of Rosario de La Frontera (La Candelaria Ridge, Salta province, NW Argentina).

""\\"Discrete fracture network (DFN) models are three-dimensional stochastic or combined . stochastic\\\\\\\/deterministic representations of fractures network that characterizes natural fracture systems. . They represent an important tool to investigate pathways for fluid flow in geothermal reservoirs in order to . predict their behavior in prospect evaluation and reservoir management. . In this project a DFN model is applied to the geothermal system of Rosario de La Frontera, in the Salta . province, with the aim to assess the effective permeability of its reservoir and to obtain input parameters for . dynamic reservoir modeling.. This active geothermal system is marked by several hot springs, with surface temperatures ranging . between 50°C and 99°C, in the surroundings of the town of Rosario de la Frontera, to the north of La . Candelaria Ridge (Fig. 1a). Fractured sandstones strata belonging to the syn-rift deposits of the Salta . Group (Pirgua subgroup) provide the reservoir rocks of this geothermal fluids (Moreno Espelta et alii, . 1975).. With the aid of dedicated software, a 3-D geological model of the La Candelaria anticline was built in order. to extract a 3-D geocellular volume of the deep reservoir to constrain the fracture network model. The reconstruction of the structure model of the La Candelaria Ridge shows a broad N-S east-verging . anticline uplifted by high-angle thrust faults.. Stuctural study on outcrops of the reservoir rocks allowed us to elaborate a deterministic fractures network . model and to calculate the input parameters for the generation of the DFN. Field work was dedicated to a . quantitative and qualitative analysis of the fractures and faults defining diagnostic parameters such as . orientation, dimension, spatial distributions, surface texture, and to calculate their density distribution within . the regional fold. The acquisition of these parameters was performed along scan-lines and on scan-areas . of the outcropping reservoir rocks. . According to orientation, the observed discontinuities were classified as longitudinal, transverse and . oblique with respect to the fold axis trend (e.g. Stearns, 1968; Hancock, 1985; Cooper, 1992), and in turn. grouped into six sets. They show different frequency values across the anticline. In particular NNW-SSE . and NE-SW trending fractures are predominant along the eastern and western limbs of the anticline, . respectively. . In conclusion, DFN models were generated for each fractures set in order to evaluate their influence on the . permeability anisotropy in different portions of the studied anticline. \\""

Quality assessment of reservoirs by means of outcrop data and "discrete fracture network" models: the case history of Rosario de La Frontera (NW Argentina) geothermal system

We report the results of a systematic study carried out on the fracture systems exposed in the Sierra de La Candelaria anticline, in the central Andean retrowedge of northwestern Argentina. The aim was to elaborate a kinematic model of the anticline and to assess the dimensional and spatial properties of the fracture network characterizing the Cretaceous sandstone reservoir of the geothermal system of Rosario de La Frontera. Special regard was devoted to explore how tectonics may affect fluid circulation at depth and control fluids' natural upwelling at surface. With this aim we performed a Discrete Fracture Network model in order to evaluate the potential of the reservoir of the studied geothermal system. The results show that the Sierra de La Candelaria regional anticline developed according to a kinematic model of transpressional inversion compatible with the latest Andean regional WNW–ESE shortening, acting on a pre-orogenic N–S normal fault. A push-up geometry developed during positive inversion controlling the development of two minor anticlines: Termas and Balboa, separated by further NNW–SSE oblique-slip fault in the northern sector of the regional anticline. Brittle deformation recorded at the outcrop scale is robustly consistent with the extensional and transpressional events recognized at regional scale. In terms of fluid circulation, the NNW–SSE and NE–SW fault planes, associated to the late stage of the positive inversion, are considered the main structures controlling the migration paths of hot fluids from the reservoir to the surface. The results of the fracture modeling performed show that fractures related to the same deformation stage, are characterized by the highest values of secondary permeability. Moreover, the DFN models performed in the reservoir volume indicates that fracture network enhances its permeability: its secondary permeability is of about 49 mD and its fractured portion represents the 0.03% of the total volume.Fil: Maffucci, Roberta. Università Roma Tre. Dipartimento di Scienze; ItaliaFil: Bigi, Sabina. Sapienza University of Rome. Department of Earth Sciences; ItaliaFil: Corrado, Sveva. Università Roma Tre. Dipartimento di Scienze; ItaliaFil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Investigaciones En Energía No Convencional; ArgentinaFil: Di Paolo, Lea. Geology and Geochemistry Labs; ItaliaFil: Giordano, Guido. Università Roma Tre. Dipartimento di Scienze; Italia. Consiglio Nazionale delle Ricerche. Sezione di Milano. Istituto per la Dinamica dei Processi Ambientali; ItaliaFil: Invernizzi, Chiara. Università degli studi di Camerino. Sezione di Geologia. Scuola di Scienze e Tecnologie; Itali

Preliminary assessment of the geothermal potential of Rosario de la Frontera area (Salta, NW Argentina): Insight from hydro-geological, hydro-geochemical and structural investigations

This work is part of a project aimed to the development and application of hydrogeological, hydrogeochemical and geological methodologies for the study of the geothermal system of Rosario de La Frontera (NW Argentina).The surface thermal manifestations of this area, whose temperatures range from 22.6 to 92.6°C, are mainly located in the northern sector of Sierra de la Candelaria anticline. This regional structure crops out between the provinces of Salta and Tucuman (NW Argentina), at the foothills of the central Andean retro-wedge.The present investigation focuses on hydrogeological and structural data, and isotopic compositions (18O, D and 3H) of thermal springs.Preliminary results allowed to define: i) the meteoric origin of spring water and their long (more than 50 years) residence time at depth, ii) a positive water balance, ranging between 2 and 4 millions of m3/yr, and iii) a conservative geothermal reservoir volume of about 39km3, iv) a geothermal potential with Er=5.6*1018J and Ef=0.8*1018J. © 2014 Elsevier Ltd.Fil: Invernizzi, Chiara. Università Degli Studi Di Camerino; ItaliaFil: Pierantoni, Pietro Paolo. Universtà Degli Studi Di Camerino; ItaliaFil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; ArgentinaFil: Maffucci, Roberta. Università Degli Studi "Roma Tre"; ItaliaFil: Corrado, Sveva. Università Degli Studi "Roma Tre"; ItaliaFil: Baez, Walter Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; ArgentinaFil: Tassi, Franco. Universita Degli Studi Di Firenze; ItaliaFil: Giordano, Guido. Università Degli Studi "Roma Tre"; ItaliaFil: Viramonte, Jose German. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energia No Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energia No Convencional; Argentin