Fluid-Rock Interaction at the Magmatic-Hydrothermal Interface of the Mount Cagua Geothermal System, Philippines

2005 ◽  
pp. 197-222
Keyword(s):  
Geothermal System ◽  
Rock Interaction

Water–rock interaction and hydrothermal mineral equilibria in the Tendaho geothermal system

1998 ◽  
Vol 86 (1-4) ◽  
pp. 253-276 ◽  
Author(s):  
Giovanni Gianelli ◽  
Negussie Mekuria ◽  
Stefano Battaglia ◽  
Alessandro Chersicla ◽  
Paolo Garofalo ◽  
...  
Keyword(s):  
Geothermal System ◽  
Rock Interaction ◽  
Mineral Equilibria ◽  
Water Rock Interaction ◽  
Hydrothermal Mineral

scholarly journals Evolution of fluid–rock interaction in the Reykjanes geothermal system, Iceland: Evidence from Iceland Deep Drilling Project core RN-17B

2015 ◽  
Vol 302 ◽  
pp. 47-63 ◽  
Author(s):  
Andrew P.G. Fowler ◽  
Robert A. Zierenberg ◽  
Peter Schiffman ◽  
Naomi Marks ◽  
Guðmundur Ómar Friðleifsson
Keyword(s):  
Geothermal System ◽  
Deep Drilling ◽  
Rock Interaction ◽  
Drilling Project

scholarly journals Water–rock interactions in the Bruchsal geothermal system by U–Th series radionuclides

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Lena Kölbel ◽  
Thomas Kölbel ◽  
Ulrich Maier ◽  
Martin Sauter ◽  
Thorsten Schäfer ◽  
...  
Keyword(s):  
Reservoir Characterization ◽  
Isotopic Fractionation ◽  
Reservoir Rock ◽  
Geothermal System ◽  
Specific Information ◽  
Radium Isotopes ◽  
Rock Interaction ◽  
Removal Time ◽  
Interaction Processes ◽  
Water Rock Interaction

Abstract Uranium and thorium decay series disequilibria in deep geothermal brines are a result of water–rock interaction processes. The migratory behavior of radionuclides provides valuable site-specific information and can therefore be an important tool for reservoir characterization and sustainable management of geothermal sites. In this study, we present data from long-term monitoring of naturally occurring 238U, 232Th and 235U series radionuclides analyzed in brine samples collected from the Permo-Triassic sedimentary reservoir rock at the Bruchsal geothermal site (SW Germany). The results show that radionuclides of the elements radium (226Ra, 228Ra, 224Ra, 223Ra), radon (222Rn), and lead (210Pb, 212Pb) are rather soluble in brine, while isotopes of uranium (238U, 234U, 235U), thorium (232Th, 228Th, 230Th), polonium (210Po), and actinium (227Ac, 228Ac) have low solubilities and are mostly immobile. Activities of radium isotopes in the geothermal brine exceed those of their thorium progenitors (average 226Ra = 29.9 Bq kg−1, about 103 times that of its 230Th parent). Modelling the observed disequilibria allows the following conclusion on water–rock interaction processes: (1) supply from alpha-recoil depends on isotope half-life because it is limited by the rate of diffusion through microfractures causing isotopic fractionation. (2) Radium retardation due to adsorption is low (226Ra/222Rn = 1.3) resulting in adsorption–desorption rate constants in the order of 10−10 s−1 for k1 and 10−9 for k2. (3) Scavenging of 226Ra from brine can best be explained by co-precipitation with barite resulting in an observed 226Ra anomaly in the solids of the reservoir section. The precipitation rate constant amounts to ca. 3.4 × 10−8 s−1 corresponding to a mean removal time of radium from brine by mineral precipitation to approximately 1 year.

scholarly journals Contribution of the Paragenetic Sequence of Clay Minerals to Re-Examination of the Alteration Zoning in the Krafla Geothermal System

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 935
Author(s):  
David Escobedo ◽  
Patricia Patrier ◽  
Daniel Beaufort ◽  
Benoit Gibert ◽  
Léa Levy ◽  
...  
Keyword(s):  
Clay Minerals ◽  
Clay Mineralogy ◽  
Hydrothermal Activity ◽  
Geothermal System ◽  
Alteration Zone ◽  
Rock Interaction ◽  
Geothermal Fluids ◽  
Alteration Zoning ◽  
Closed Systems ◽  
Host Rocks

This paper revisits the clay mineralogy of the “smectite” alteration zone in the Krafla geo-thermal field via the study of an exploratory well in which temperatures range from 40 °C to 215 °C. The clay alteration consists of several mineral assemblages superimposed in time and space, resulting from different stages of water-rock interaction. Trioctahedral clay minerals (chlorite, corrensite and smectite) are observed throughout the studied section. These minerals can form in nearly closed systems as replacements of groundmass minerals/glass after interactions with resident and nearly stagnant fluids not far from chemical equilibrium (neutral to basic pH conditions) or from direct precipitation from geothermal fluids. They are locally superimposed by Al clay phases (smectite, illite/smectite and kaolinite), which result from intense leaching of the host rocks due to their interaction with low pH fluids under strong W/R ratios. The absence of mineralogical zoning is explained by the fact that hydrothermal alteration is strongly dependent on very recent hydrodynamics. The current fluid circulation generates trioctahedral clays at depth that cannot be distinguished from pervasive earlier alteration. The only easily detectable signature of current activity and the most relevant signature for geothermal exploration is the presence of Al dioctahedral phases since it indicates leaching and intense hydrothermal activity.

Geothermal manifestations in the Tyrrhenian area: the role of faults in channelling superhot geothermal fluids

2021 ◽  
Author(s):  
Martina Zucchi
Keyword(s):  
Fluid Flow ◽  
Fault Zones ◽  
Ore Deposits ◽  
Contact Metamorphism ◽  
Normal Faults ◽  
Geothermal System ◽  
Low Permeability ◽  
Geothermal Systems ◽  
Rock Interaction ◽  
Geothermal Fluids

<div> <p><span>Extensional tectonics and related magmatism affecting continental crust can favour the development of geothermal systems. Granitoids intruded in the upper crust represent the main expression of magmatism; they are strictly controlled by brittle structures during their emplacement and exhumation. The cooling of the magmatic bodies produce a thermal perturbation in the hosting rocks resulting in thermo-metamorphic aureoles of several meter thick, usually characterised by valuable ore deposits. After the emplacement and during the cooling stage such granitoids can promote the geothermal fluids circulation mainly through the fault zones. In case of favourable geological and structural conditions, geothermal fluids can be stored in geological traps (reservoirs), generally represented by rock volumes with sufficient permeability for storing a significant amount of fluid. Traps are confined, at the top, by rocks characterised by low, or very low permeability, referred to as the cap rocks of a geothermal system. Several studies are addressed to the study of fluid migration through the permeable rock volumes, whereas few papers are dealing with fluid flow and fluid-rock interaction within the cap rocks. </span></p> </div><div> <p><span>In this presentation, an example of fault-controlled geothermal fluid within low permeability rocks is presented. The study area is located in the south-eastern side of Elba Island (Tuscan Archipelago, Italy), where a succession made up of shale, marl and limestone (Argille a Palombini Fm, early Cretaceous) was affected by contact metamorphism related to the Porto Azzurro monzogranite, which produced different mineral assemblages, depending on the involved lithotypes. These metamorphic rocks were dissected by high-angle normal faults that channelled superhot geothermal fluids. Fluid inclusions analyses on hydrothermal quartz and calcite suggest that at least three paleo-geothermal fluids permeated through the fault zones, at a maximum P of about 0.8 kbar. The results reveal how brittle deformation induces fluid flow in rocks characterised by very low permeability and allow the characterisation of the paleo-geothermal fluids in terms of salinity and P-T trapping conditions. </span></p> </div>

scholarly journals Hydrothermal Alteration at the San Vito Area of the Campi Flegrei Geothermal System in Italy: Mineral Review and Geochemical Modeling

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 810
Author(s):  
Monica Piochi ◽  
Barbara Cantucci ◽  
Giordano Montegrossi ◽  
Gilda Currenti
Keyword(s):  
Reactive Transport ◽  
Numerical Models ◽  
Geochemical Modeling ◽  
Relevant Information ◽  
Campi Flegrei ◽  
Geothermal System ◽  
Data Set ◽  
Rock Interaction ◽  
Geochemical Model ◽  
Rock Formations

The Campi Flegrei geothermal system sets in one of the most famous and hazardous volcanic caldera in the world. The geothermal dynamics is suspected to have a crucial role in the monitored unrest phases and in the eruption triggering as well. Numerical models in the literature do not properly consider the geochemical effects of fluid-rock interaction into the hydrothermal circulation and this gap limits the wholly understanding of the dynamics. This paper focuses on fluid-rock interaction effects at the Campi Flegrei and presents relevant information requested for reactive transport simulations. In particular, we provide: (1) an extensive review of available data and new petrographic analyses of the San Vito cores rearranged in a conceptual model useful to define representative geochemical and petrophysical parameters of rock formations suitable for numerical simulations and (2) the implemented thermodynamic and kinetic data set calibrated for the San Vito 1 well area, central in the geothermal reservoir. A preliminary 0D-geochemical model, performed with a different contribution of CO2 at high (165 °C) and low (85 °C) temperatures, firstly allows reproducing the hydrothermal reactions over time of the Campanian Ignimbrite formation, the most important deposits in the case study area.

scholarly journals Simulation of water–rock interaction in the Yellowstone geothermal system using TOUGHREACT

Geothermics ◽  
2004 ◽  
Vol 33 (4) ◽  
pp. 493-502 ◽  
Author(s):  
Patrick F Dobson ◽  
Sonia Salah ◽  
Nicolas Spycher ◽  
Eric L Sonnenthal
Keyword(s):  
Geothermal System ◽  
Rock Interaction ◽  
Water Rock Interaction
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