Hydrothermal Systems hydrothermal system , Geochemistry hydrothermal system geochemistry of

The Tatun Volcano Group (TVG) is located in northern Taiwan and consists of many springs and fumaroles. The Tayukeng (TYK) area is the most active fumarole site in the TVG. In this study, we analyzed the long-term geochemical variations of hydrothermal fluids and proposed a mechanism responsible for the variation in TYK. There are two different aquifers beneath the TYK area: a shallow SO42−-rich aquifer and a deeper aquifer rich in Cl−. TYK thermal water was mainly supplied by the shallow SO42−-rich aquifer; therefore, the thermal water showed high SO42− concentrations. After 2015, the inflow of deep thermal water increased, causing the Cl− concentrations of the TYK to increase. Notably, the inferred reservoir temperatures based on quartz geothermometry increased; however, the surface temperature of the spring decreased. We inferred that the enthalpy was lost during transportation to the surface. Therefore, the surface temperature of the spring does not increase with an increased inflow of deep hydrothermal fluid. The results can serve as a reference for understanding the complex evolution of the magma-hydrothermal system in the TVG.

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Mercury concentrations in thermal waters of the Bolshoi Semyachik hydrothermal system, Russia, Kamchatka.

10.5194/egusphere-egu21-15094 ◽

2021 ◽

Author(s):

Anton Nuzhdaev

Keyword(s):

Hydrothermal System ◽

Kamchatka Peninsula ◽

Hydrothermal Systems ◽

Thermal Waters ◽

Hydrothermal Solutions ◽

Average Value ◽

Thermal Fields ◽

Gas Jets ◽

First Time ◽

Hydrothermal Fields

The study of mercury receipt within volcanic activity zones and large hydrothermal systems recently causes the big interest connected with attempts of an estimation of volumes of natural mercury receipt on a daily surface.The hydrothermal system connected with volcanic massif Big Semyachik is one of the largest on the territory of Kamchatka peninsula. On the surface, the hydrothermal system is manifested by three large hydrothermal fields - the Verhnee Field, the parychay Dolina, and the Northern Crater of the Central Semyachik, the heat export from which is estimated at 300 MW (Vakin, 1976). On the surface of the thermal fields hot thermal waters and powerful steam-gas jets are unloaded.&#160; At the same time, due to the inaccessibility of thermal fields remain poorly studied, and in particular, there is no information on the concentrations of mercury in hydrothermal solutions.During fieldwork in 2020 all types of thermal waters were sampled, chemical types of waters were established, concentrations of mercury in hydrothermal solutions: for hot thermal waters the average value of mercury was - 0.44 mcg / L, and in steam-gas jets - the average value of mercury was - 4.60 mcg / L.Thus, in the course of the work the data on concentrations of mercury in hydrothermal solutions of one of the largest hydrothermal systems of Kamchatka were received for the first time.&#160;

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Hydrothermal systems generation scheduling using cultural algorithm

Journal of Hydroinformatics ◽

10.2166/hydro.2009.056 ◽

2009 ◽

Vol 11 (1) ◽

pp. 65-78 ◽

Cited By ~ 8

Author(s):

Xiaohui Yuan ◽

Hao Nie ◽

Yanbin Yuan ◽

Anjun Su ◽

Liang Wang

Keyword(s):

Differential Evolution ◽

Heuristic Search ◽

Hydrothermal System ◽

Selection Criteria ◽

Optimization Methods ◽

Hydrothermal Systems ◽

Cultural Algorithm ◽

Short Term ◽

Generation Scheduling ◽

Simple Selection

This paper proposes an enhanced cultural algorithm to solve the short-term generation scheduling of hydrothermal systems problem, in which differential evolution is embedded into a cultural algorithm and applies two knowledge sources to influence the variation operator of differential evolution and couples with simple selection criteria based on feasibility rules and heuristic search strategies to handle constraints in the cultural algorithm effectively. A test hydrothermal system is used to verify the feasibility and effectiveness of the proposed method. Results are compared with those of other optimization methods reported in the literature. It is shown that the proposed method is capable of yielding higher quality solutions.

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Aquatic Thermal Reservoirs of Microbial Life in a Remote and Extreme High Andean Hydrothermal System

Microorganisms ◽

10.3390/microorganisms8020208 ◽

2020 ◽

Vol 8 (2) ◽

pp. 208

Author(s):

Vilma Pérez ◽

Johanna Cortés ◽

Francisca Marchant ◽

Cristina Dorador ◽

Verónica Molina ◽

...

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Microbial Diversity ◽

Hydrothermal System ◽

Benthic Communities ◽

Hydrothermal Systems ◽

Rrna Gene ◽

Clone Libraries ◽

Bacterial Clone ◽

Hydrothermal Ecosystem

Hydrothermal systems are ideal to understand how microbial communities cope with challenging conditions. Lirima, our study site, is a polyextreme, high-altitude, hydrothermal ecosystem located in the Chilean Andean highlands. Herein, we analyze the benthic communities of three nearby springs in a gradient of temperature (42–72 °C represented by stations P42, P53, and P72) and pH, and we characterize their microbial diversity by using bacteria 16S rRNA (V4) gene metabarcoding and 16S rRNA gene clone libraries (bacteria and archaea). Bacterial clone libraries of P42 and P53 springs showed that the community composition was mainly represented by phototrophic bacteria (Chlorobia, 3%, Cyanobacteria 3%, at P42; Chlorobia 5%, and Chloroflexi 5% at P53), Firmicutes (32% at P42 and 43% at P53) and Gammaproteobacteria (13% at P42 and 29% at P53). Furthermore, bacterial communities that were analyzed by 16S rRNA gene metabarcoding were characterized by an overall predominance of Chloroflexi in springs with lower temperatures (33% at P42), followed by Firmicutes in hotter springs (50% at P72). The archaeal diversity of P42 and P53 were represented by taxa belonging to Crenarchaeota, Diapherotrites, Nanoarchaeota, Hadesarchaeota, Thaumarchaeota, and Euryarchaeota. The microbial diversity of the Lirima hydrothermal system is represented by groups from deep branches of the tree of life, suggesting this ecosystem as a reservoir of primitive life and a key system to study the processes that shaped the evolution of the biosphere.

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Theoretical inversion of the fossil hydrothermal systems with oxygen isotopes of constituent minerals partially re-equilibrated with externally infiltrated fluids

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s1755691021000244 ◽

2021 ◽

pp. 1-10

Author(s):

Chun-Sheng WEI ◽

Zi-Fu ZHAO

Keyword(s):

Oxygen Isotopes ◽

Hydrothermal System ◽

Meteoric Water ◽

Surface Reaction ◽

Country Rock ◽

Eastern China ◽

Hydrothermal Systems ◽

Dabie Orogen ◽

Magmatic Water ◽

Initial Oxygen

ABSTRACT While the external infiltration of water has been identified from modern geothermal and/or fossil hydrothermal systems through stable isotopes, the physicochemical boundary conditions like the initial oxygen isotopes of water $( {{\rm \delta }^{ 18}{\rm O}_{\rm W}^{\rm i} } ) $ and rock as well as alteration temperature were implicitly presumed or empirically estimated by the conventional forward modelling. In terms of a novel procedure proposed to deal with partial re-equilibration of oxygen isotopes between constituent minerals and water, the externally infiltrated meteoric and magmatic water are theoretically inverted from the early Cretaceous post-collisional granitoid and intruded Triassic gneissic country rock across the Dabie orogen in central-eastern China. The meteoric water with a $ {{\rm \delta }^{ 18}{\rm O}_{\rm W}^{\rm i} } $ value of −11.01 ‰ was externally infiltrated with a granitoid and thermodynamically re-equilibrated with rock-forming minerals at 140°C with a minimum water/rock (W/R)o ratio around 1.10 for an open system. The lifetime of this meteoric hydrothermal system is kinetically constrained less than 0.7 million years (Myr) via modelling of surface reaction oxygen exchange. A gneissic country rock, however, was externally infiltrated by a magmatic water with $ {{\rm \delta }^{ 18}{\rm O}_{\rm W}^{\rm i} } $ value of 4.21 ‰ at 340°C with a (W/R)o ratio of 1.23, and this magmatic hydrothermal system could last no more than 12 thousand years (Kyr) to rapidly re-equilibrate with rock-forming minerals. Nevertheless, the external infiltration of water can be theoretically inverted with oxygen isotopes of re-equilibrated rock-forming minerals, and the ancient hydrothermal systems driven by magmatism or metamorphism within continental orogens worldwide can be reliably quantified.

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Response of a Hydrothermal System to Escalating Phreatic Unrest the Case of Turrialba and Irazú in Costa Rica (2007-2012)

10.21203/rs.3.rs-139302/v1 ◽

2021 ◽

Author(s):

Dmitri Rouwet ◽

Raul Mora-Amador ◽

Carlos Ramirez ◽

Gino González-Ilama ◽

Eleonora Baldoni ◽

...

Keyword(s):

Costa Rica ◽

Hydrothermal System ◽

Crater Lake ◽

Removal Rate ◽

Summit Crater ◽

Hydrothermal Systems ◽

Thermal Springs ◽

Total Output ◽

Crater Lakes ◽

Phreatic Eruptions

Abstract This study presents the first hydrogeochemical model of the hydrothermal systems of Turrialba and Irazú volcanoes in central Costa Rica, manifested as thermal springs, summit crater lakes, and fumarolic degassing at both volcanoes. Our period of observations (2007-2012) coincides with the pre- and early syn-phreatic eruption stages of Turrialba volcano that resumed volcanic unrest since 2004, after almost 140 years of quiescence. Peculiarly, the generally stable Irazú crater lake dropped its level during this reawakening of Turrialba. The isotopic composition of discharged fluids reveals the Caribbean meteoric origin; a contribution of “andesitic water” for Turrialba fumaroles up to ~50% is suggested. Four groups of thermal springs drain the northern flanks of Turrialba and Irazú volcanoes into two main rivers. Río Sucio (i.e. “dirty river”) is a major rock remover on the North flank of Irazú, mainly fed by the San Cayetano spring group. Instead, one group of thermal springs discharges towards the south of Irazú. All thermal spring waters are of SO4-type (i.e. steam heated waters), although none of the springs has a common hydrothermal end-member. A water mass budget for thermal springs results in an estimated total output flux of 187 ± 37 L/s, with 100 ± 20 L/s accounted for by the San Cayetano springs. Thermal energy release is estimated at 110 ± 22 MW (83.9 ± 16.8 MW by San Cayetano), whereas the total rock mass removal rate by chemical leaching is ~3,000 m3/y (~2,400 m3/y by San Cayetano-Río Sucio). Despite Irazú being the currently less active volcano, it is a highly efficient rock remover, which, on the long term can have effects on the stability of the volcanic edifice with potentially hazardous consequences (e.g. flank collapse, phreatic eruptions). Moreover, the vapor output flux from the Turrialba fumaroles after the onset of phreatic eruptions on 5 January 2010 showed an increase of at least ~260 L/s above pre-eruptive background fumarolic vapor fluxes. This extra vapor loss implies that the drying of the summit hydrothermal system of Turrialba could tap deeper than previously thought, and could explain the coincidental disappearance of Irazú’s crater lake in April 2010.

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3-D Geoelectrical Characterisation of the Central Volcanoes of São Miguel Island (Azores Archipelago, Portugal) using Broad-Band Magnetotelluric Data

10.5194/egusphere-egu2020-10695 ◽

2020 ◽

Author(s):

Duygu Kiyan ◽

Colin Hogg ◽

Volker Rath ◽

Andreas Junge ◽

Rita Carmo ◽

...

Keyword(s):

Fracture Zone ◽

Hydrothermal System ◽

High Frequency ◽

Broad Band ◽

Hydrothermal Systems ◽

Volcanic System ◽

Magnetotelluric Soundings ◽

Field Campaign ◽

The North ◽

Swarm Activity

The Azores islands are located at the triple junction between the North American, Eurasian and African plates. The Mid-Atlantic Ridge separates the North America from Eurasia and African plates, while Azores-Gibraltar Fracture Zone is the boundary between Eurasia and African plates. S&#227;o Miguel Island, situated at the southeastern part of the western segment of the Azores-Gibraltar Fracture Zone, has three active strato-volcanoes, Sete Cidades, Fogo (&#193;gua de Pau), and Furnas. At Furnas and Fogo volcanoes, intense circulation of volcanic fluids at depth leads to high CO2 outgassing and flank destabilisation, whereas its neighbour Congro Fissural volcanic system, located between Fogo and Furnas volcanoes, experiences significant seismic swarm activity and poses considerable threat to the local population. Enhanced electrical conductivity values are typically associated with volcanic-hydrothermal systems and the modelled conductivity structures can provide constraints on these volcanic and hydrothermal processes.Our previous work on Furnas volcano, which yielded a revised conceptual model developed from 39 high-frequency magnetotelluric soundings that imaged the hydrothermal system of the volcano to a depth of 1 km directly beneath the caldera, has now been expanded to include 35 additional broad-band magnetotelluric soundings from a recent field campaign conducted in late 2018, to image deeper and broader to gain new insights into the regional context of the Furnas volcanic system. The resistivity model of Furnas shallow hydrothermal system constructed from high-frequency dataset delineated two enhanced conductive zones, one at 100 m and another at 500 m depth, separated by a resistive layer. The shallow conductor has conductivity less than 1 S/m, which can be explained by clay mineral surface conduction with a mass fraction of at least 20% smectite. The deeper conductor extends across the majority of the survey area and is located at depths where smectite is generally not formed. We interpret this as the result of saline aqueous fluids near the boiling point, inferring temperatures of at least 240 oC. The less conductive layer found between these conductors is interpreted to be steam-dominated and coincides within the mixed-clay zone found in many volcanic hydrothermal systems. 3-D inversions using the deep-probing data indicate continuation of a strong conductive zone towards the south, beneath the 1630 Dome, which represents the most recent phase of eruptive activity in the multi-caldera complex. During the 2018 field campaign, we have enlarged our study to include 50 broad-band soundings on the adjacent Fogo (&#193;gua de Pau) volcano and Congro Fissural volcanic system. The Fogo-Congro region is subjected to seismic swarm activity and its relationship with the geoelectrical structure is being investigated.

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Distribution and Transport of Thermal Energy within Magma–Hydrothermal Systems

Geosciences ◽

10.3390/geosciences10060212 ◽

2020 ◽

Vol 10 (6) ◽

pp. 212 ◽

Cited By ~ 1

Author(s):

John Eichelberger

Keyword(s):

Heat Flux ◽

Hydrothermal System ◽

Lava Lake ◽

Crystallization Rate ◽

Hydrothermal Systems ◽

Constant Thickness ◽

Magma Body ◽

Lower Face ◽

Rhyolite Magma ◽

Upper Face

Proximity to magma bodies is generally acknowledged as providing the energy source for hot hydrothermal reservoirs. Hence, it is appropriate to think of a “magma–hydrothermal system” as an entity, rather than as separate systems. Repeated coring of Kilauea Iki lava lake on Kilauea Volcano, Hawaii, has provided evidence of an impermeable, conductive layer, or magma–hydrothermal boundary (MHB), between a hydrothermal system and molten rock. Crystallization on the lower face of the MHB and cracking by cooling on the upper face drive the zone downward while maintaining constant thickness, a Stefan problem of moving thermal boundaries with a phase change. Use of the observed thermal gradient in MHB of 84 °C/m yields a heat flux of 130 W/m2. Equating this with the heat flux produced by crystallization and cooling of molten lava successfully predicts the growth rate of lava lake crust of 2 m/a, which is faster than simple conduction where crust thickens at t and heat flux declines with 1 / t . However, a lava lake is not a magma chamber. Compared to erupted and degassed lava, magma at depth contains a significant amount of dissolved water that influences the magma’s thermal, chemical, and mechanical behaviors. Also, a lava lake is rootless; it has no source of heat and mass, whereas there are probably few shallow, active magma bodies that are isolated from deeper sources. Drilling at Krafla Caldera, Iceland, showed the existence of a near-liquidus rhyolite magma body at 2.1 km depth capped by an MHB with a heat flux of ≥16 W/m2. This would predict a crystallization rate of 0.6 m/a, yet no evidence of crystallization and the development of a mush zone at the base of MHB is observed. Instead, the lower face of MHB is undergoing partial melting. The explanation would appear to lie in vigorous convection of the hot rhyolite magma, delivering both heat and H2O but not crystals to its ceiling. This challenges existing concepts of magma chambers and has important implications for use of magma as the ultimate geothermal power source. It also illuminates the possibility of directly monitoring magma beneath active volcanoes for eruption forecasting.

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Machine learning to identify geologic factors associated with production in geothermal fields: a case-study using 3D geologic data, Brady geothermal field, Nevada

Geothermal Energy ◽

10.1186/s40517-021-00199-8 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Drew L. Siler ◽

Jeff D. Pepin ◽

Velimir V. Vesselinov ◽

Maruti K. Mudunuru ◽

Bulbul Ahmmed

Keyword(s):

Machine Learning ◽

Fluid Flow ◽

Hydrothermal System ◽

Geothermal Field ◽

Hydrothermal Systems ◽

Electricity Production ◽

Fault System ◽

Macro Scale ◽

Geologic Data ◽

Geologic Controls

AbstractIn this paper, we present an analysis using unsupervised machine learning (ML) to identify the key geologic factors that contribute to the geothermal production in Brady geothermal field. Brady is a hydrothermal system in northwestern Nevada that supports both electricity production and direct use of hydrothermal fluids. Transmissive fluid-flow pathways are relatively rare in the subsurface, but are critical components of hydrothermal systems like Brady and many other types of fluid-flow systems in fractured rock. Here, we analyze geologic data with ML methods to unravel the local geologic controls on these pathways. The ML method, non-negative matrix factorization with k-means clustering (NMFk), is applied to a library of 14 3D geologic characteristics hypothesized to control hydrothermal circulation in the Brady geothermal field. Our results indicate that macro-scale faults and a local step-over in the fault system preferentially occur along production wells when compared to injection wells and non-productive wells. We infer that these are the key geologic characteristics that control the through-going hydrothermal transmission pathways at Brady. Our results demonstrate: (1) the specific geologic controls on the Brady hydrothermal system and (2) the efficacy of pairing ML techniques with 3D geologic characterization to enhance the understanding of subsurface processes.

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Three-dimensional inversion of audio-magnetotelluric data acquired from the crater area of Mt. Tokachidake, Japan

Earth Planets and Space ◽

10.1186/s40623-021-01502-4 ◽

2021 ◽

Vol 73 (1) ◽

Author(s):

Ryo Tanaka ◽

Yusuke Yamaya ◽

Makoto Tamura ◽

Takeshi Hashimoto ◽

Noritoshi Okazaki ◽

...

Keyword(s):

Hydrothermal System ◽

Hydrothermal Fluid ◽

Three Dimensional ◽

Hydrothermal Systems ◽

High Resistivity ◽

Water Volume ◽

Resistivity Structure ◽

Magnetotelluric Data ◽

Resistive Layer ◽

Active Crater

AbstractSubvolcanic hydrothermal systems can lead to hydrothermal eruptions as well as unrest phenomena without an eruptive event. Historical eruptions and recent unrest events, including ground inflation, demagnetization, and a gradual decrease in the plume height, at Mt. Tokachidake, central Hokkaido, Japan, are related to such a subvolcanic hydrothermal system. This study investigates the three-dimensional (3-D) resistivity structure of Mt. Tokachidake to image its subvolcanic hydrothermal system. A 3-D inversion of the magnetotelluric data, acquired at 22 sites around the crater area, was performed while accounting for the topography. Our resistivity model was characterized by a high-resistivity layer at a shallow depth (50–100 m) and two conductors near the active crater and dormant crater. The high-resistivity layer was interpreted to be composed of dense lava, which acts as a caprock surrounding the conductor. The high conductivity beneath the active crater can be explained by the presence of hydrothermal fluid in fractured or leached zones within the low-permeability lava layer, as the sources of ground inflation and demagnetization were identified within the conductive zone immediately beneath the resistive layer. The resistivity structure was used to estimate the volume of hydrothermal fluid within the pore space. The minimum volume of hydrothermal fluid beneath the active crater that can explain the resistivity structure was estimated to be 3 × 106 m3. This estimate is comparable to the water volume that was associated with the long runout and highly fluidized lahar in 1926. The resistivity structure and volume of hydrothermal fluid presented in this study can be used as a reference for further numerical simulations, which aim to reveal the mechanisms of recent unrest events and assess the risk of hazards, such as lahar.

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