scholarly journals Geysers

2021 ◽  
pp. 289-299
Author(s):  
Chi-Yuen Wang ◽  
Michael Manga
Keyword(s):  
Hydrothermal Systems ◽  
Boiling Water ◽  
Data Sets ◽  
Geothermal Systems ◽  
Surface Manifestation

AbstractGeysers, springs that intermittently erupt boiling water, appear to be especially sensitive to earthquakes. As they are a surface manifestation of geothermal systems, their response to earthquakes provides a window into how earthquakes change hydrothermal systems and processes. The most common approach to document responses to earthquakes is to identify changes in the interval between eruptions. Sustained changes in eruption intervals may be caused by changes in permeability. Confirming what processes lead to changes at geysers is hampered by limited reliable, quantitative multi-parameter data sets.

scholarly journals Imaging Thermal Anomalies in Hot Dry Rock Geothermal Systems from Near-Surface Geophysical Modelling

2019 ◽  
Vol 11 (6) ◽  
pp. 675 ◽  
Author(s):  
David Gomez-Ortiz ◽  
Isabel Blanco-Montenegro ◽  
Jose Arnoso ◽  
Tomas Martin-Crespo ◽  
Mercedes Solla ◽  
...  
Keyword(s):  
Ground Penetrating Radar ◽  
Electromagnetic Induction ◽  
Hydrothermal Systems ◽  
Ground Temperature ◽  
Geothermal Systems ◽  
Near Surface ◽  
Hot Dry Rock ◽  
Ground Temperatures ◽  
Imaging Results ◽  
Ground Penetrating

Convective hydrothermal systems have been extensively studied using electrical and electromagnetic methods given the strong correlation between low conductivity anomalies associated with hydrothermal brines and high temperature areas. However, studies addressing the application of similar geophysical methods to hot dry rock geothermal systems are very limited in the literature. The Timanfaya volcanic area, located on Lanzarote Island (Canary Islands), comprises one of these hot dry rock systems, where ground temperatures ranging from 250 to 605 °C have been recorded in pyroclastic deposits at shallow (<70 m) depths. With the aim of characterizing the geophysical signature of the high ground temperature areas, three different geophysical techniques (ground penetrating radar, electromagnetic induction and magnetic prospecting) were applied in a well-known geothermal area located inside Timanfaya National Park. The area with the highest ground temperatures was correlated with the location that exhibited strong ground penetrating radar reflections, high resistivity values and low magnetic anomalies. Moreover, the high ground temperature imaging results depicted a shallow, bowl-shaped body that narrowed and deepened vertically to a depth greater than 45 m. The ground penetrating radar survey was repeated three years later and exhibited subtle variations of the signal reflection patterns, or signatures, suggesting a certain temporal variation of the ground temperature. By identifying similar areas with the same geophysical signature, up to four additional geothermal areas were revealed. We conclude that the combined use of ground penetrating radar, electromagnetic induction and magnetic methods constitutes a valuable tool to locate and study both the geometry at depth and seasonal variability of geothermal areas associated with hot dry rock systems.

A New Approach to Characterizing Deposit Type Using Mineral Inclusion Assemblages in Gold Particles

2021 ◽  
Author(s):  
R. J. Chapman ◽  
J. K. Mortensen ◽  
M. M. Allan ◽  
R. D. Walshaw ◽  
J. Bond ◽  
...  
Keyword(s):  
Unknown Origin ◽  
Hydrothermal Systems ◽  
Mineral Inclusion ◽  
Canadian Cordillera ◽  
Data Sets ◽  
Simple Method ◽  
Gold Particles ◽  
Deposit Type ◽  
Placer Deposits ◽  
Detrital Particles

Abstract Mineral inclusions within native gold are features of lode gold occurrences that are preserved in detrital particles. Inclusion assemblages in populations of gold particles in placers from specific localities are revealed through inspection of polished sections, and assimilation of robust data sets permits reconstruction of the lode source mineralogy. Inclusion assemblages differ considerably according to the source deposit type, and various approaches have been employed to graphically represent inclusion mineralogy. We present a simple method for depicting and comparing inclusion assemblages using a single standardized radar diagram template that illustrates the proportions of 11 metal and 5 nonmetal (and metalloid) elements in each inclusion assemblage. The Canadian Cordillera hosts many different gold-bearing deposit types and is an ideal terrane in which to develop a globally applicable methodology. Although placer gold is widespread, the location and nature of source mineralization is commonly unclear. This study is based on the inclusion suites recorded in 37 sample sets of gold particles from both placer and lode localities. Radar diagrams describing inclusion assemblages show clear generic differences according to deposit type. Diagnostic signatures have been established and act as templates against which samples of unknown origin may be compared. This approach permits differentiation between populations of gold particles formed in different magmatic systems (low-sulfidation epithermal, calc-alkalic porphyry, and alkalic porphyry), which may all be distinguished from gold formed in orogenic (amagmatic) mineralization. Metallic element signatures are most useful in differentiating gold from different magmatic hydrothermal systems, whereas nonmetallic elements allow for classification of orogenic gold subtypes. Comparisons of mineral inclusion signatures from gold in the Canadian Cordillera with samples from similar geologic settings worldwide suggest that this approach to gold fingerprinting is globally applicable. Therefore, the geochemical signatures of inclusion assemblages provide a robust indication of deposit type and may be applied in exploration to illuminate regional metallogeny in areas where relationships between placer deposits and their source(s) may be unclear.

Diffuse H2 and He degassing survey to study of hidden potential geothermal systems in La Palma, Canary Islands

2020 ◽  
Author(s):  
Fátima Rodríguez ◽  
Antonio Polo Sánchez ◽  
Katherine Dale ◽  
Chloe Codner ◽  
Alba Martín ◽  
...  
Keyword(s):  
Rift Zone ◽  
Average Distance ◽  
Hydrothermal Systems ◽  
Soil Gas ◽  
Geothermal Systems ◽  
Soil Matrix ◽  
North West ◽  
The North ◽  
La Palma ◽  
Cumbre Vieja

&lt;p&gt;La Palma is one of the eastern islands of the Canary Archipelago located off the West African continental margin. Volcanic activity in the last 123 ka has taken place exclusively at the southern part of the island, where Cumbre Vieja volcano has been formed. Cumbre Vieja, one of the most active basaltic volcano in the Canaries, host seven historical eruptions being Tenegu&amp;#237;a eruption (1971) the most recent one. Cumbre Vieja volcano, characterized by a main north&amp;#8211;south rift zone 20 km long and covering an area of 220 km&lt;sup&gt;2&lt;/sup&gt;, does not show any visible degassing that show the existence of active geothermal systems. For that reason, geochemical prospecting of soil gases and volatiles in the soil matrix itself of Cumbre Vieja can provide useful information to investigate the presence of permeable areas and potential upflow areas for the degassing of geothermal systems at depth.&lt;/p&gt;&lt;p&gt;We report herein the results of an intensive soil gas study, focused on non-reactive and/or highly mobile gases such as helium (He) and hydrogen (H&lt;sub&gt;2&lt;/sub&gt;), in Cumbre Vieja, with geothermal exploration purposes. He has unique characteristics as a geochemical tracer: it is chemically inert and radioactively stable, non-biogenic, highly mobile and relatively insoluble in water. H&lt;sub&gt;2&lt;/sub&gt; is one of the most abundant trace species in volcano-hydrothermal systems and is a key participant in many redox reactions occurring in the hydrothermal reservoir gas.&lt;/p&gt;&lt;p&gt;Soil gas samples were collected at 1,201 sites selected from June 2019 to September 2019, with an average distance between sites of &amp;#8776; 250 m, at &amp;#8776; 40 cm depth using a metallic probe. He content was analyzed by means of a quadrupole mass spectrometer (QMS; Pfeiffer Omnistar 422) and hydrogen concentrations by a micro-gas chromatograph (microGC; VARIAN CP490). Soil He concentration showed values up to 23.9 ppm with an average of 5.73 ppm. Soil H&lt;sub&gt;2&lt;/sub&gt; concentrations measured ranged from typical atmospheric values (&amp;#8776; 0.5 ppm) up to 19.8 ppm. The mean value measured for H&lt;sub&gt;2&lt;/sub&gt; was 0.78 ppm. Although He concentration values showed high spatial variability, the highest values can be observed in the north&amp;#8211;south rift zone of Cumbre Vieja and around the surface contact with Cumbre Nueva ridge. Spatial distribution of H&lt;sub&gt;2&lt;/sub&gt; concentration showed the highest values in the north-west area of Cumbre Vieja volcano. The results showed here are useful to identify the possible existence of permeable portions of deep-seated actively degassing geothermal reservoirs. However, a multidisciplinary approach is essential to obtain additional information about possible geothermal systems underlying at Palma island with the last goal of the selection of appropriate locations for future exploratory wells.&lt;/p&gt;

Unraveling Zr/Hf fractionation: Hydrothermal zirconium and hafnium fluoride complexation up to 400°C

2020 ◽  
Author(s):  
Anselm Loges ◽  
Marion Louvel ◽  
Max Wilke ◽  
Sthephan Klemme ◽  
Timm John ◽  
...  
Keyword(s):  
Hydrothermal Systems ◽  
Effect Of Temperature ◽  
Data Sets ◽  
Strong Temperature Dependence ◽  
Aqueous Solvent ◽  
Fluoride Complexation ◽  
Fluoride Complexes ◽  
The Stability ◽  
Hydrothermal Environments ◽  
Aqueous Complexes

&lt;p&gt;High field strength elements (HFSE) such as Zr and Hf are relatively insoluble in most natural hydrothermal solutions and consequently immobile in most geological systems. However, fluoride forms stable aqueous complexes with many HFSE ions, including Zr&lt;sup&gt;4+&lt;/sup&gt; and Hf&lt;sup&gt;4+&lt;/sup&gt;, and is thus a potent mobilizer of these elements. Due to their identical charge and similar ionic radius (590 pm and 580 pm, respectively), Zr and Hf behave almost identically in geological system and are therefore referred to as geochemical twins. Fluoride complexation in hydrothermal environments is one of few processes in the Earth's crust that can effectively fractionate them from one another. This fact can be used to trace past fluoride activity in fossil hydrothermal systems by investigating Zr/Hf ratios, if fluoride complexation of Zr and Hf is sufficiently well understood. Mobility of metals as complexes is controlled by two distinct but related mechanisms: Formation of the complex itself and solvation of that complex in the solvent. Poly(hydrogen-fluoride) bridging of fluoride complexes to the surrounding aqueous solvent is crucial to the understanding of the solvation and therefore the mobility of fluoride complexes.&lt;/p&gt;&lt;p&gt;We report geometries of Zr and Hf fluoride complexes up to 400&amp;#176;C, determined by extended X-Ray absorption fine structure (EXAFS) in a hydrothermal autoclave. Existing data sets on the stability of those complexes at lower temperatures are extended to 400&amp;#176;C. Our data show strong temperature dependence of the complex stability for both metals. However, the effect of temperature is not equally strong for Zr and Hf. Fractionation of the twin pair is thus a function of temperature as well as fluoride activity.&lt;/p&gt;

Expanding a Geothermal Field Downwards. The Challenge of Drilling a Deep Well in the Hengill Area, SW Iceland.

2020 ◽  
Author(s):  
Gunnar Gunnarsson ◽  
Vignir Demusson ◽  
Ingvi Gunnarsson ◽  
Bjarni Reyr Kristjánsson ◽  
Sigrún Tómasdóttir ◽  
...  
Keyword(s):  
Geothermal Field ◽  
Hydrothermal Systems ◽  
Measured Temperature ◽  
Geothermal Systems ◽  
Magma Body ◽  
Deep Well ◽  
Well Design ◽  
Geothermal Fields ◽  
Original Plan ◽  
Promising Target

&lt;p&gt;&lt;span&gt;In 1986 a well, which was planned as a convetional production well in the Nesjavellir Field in the Hengill Area, SW Iceland, was unexpectedly drilled into a very hot formation at the depth of 2.1&amp;#160;km. The measured temperature in the lowest part of the well was 380&amp;#176;C, which was the upper range of the measuring tool used. Thus, the bottom-hole temperature was most probably higher. No one expected to hit such a hot body in this place and the well design was not appropriate to handle such high temperatures and resulting pressures. Thus, the lower parts of that well were closed off and it has since then been operated as a conventional geothermal well.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;This incidence sparked the idea of drilling deeper into volcanic hydrothermal systems in Iceland in order to gain a better understanding of the roots of the geothermal systems and to be able to produce fluids with higher enthalpy. The Iceland Deep Drilling Project (IDDP) is supposed to realize that idea. The IDDP project is a consortium of domestic and international partners, both from industry and academia. The three power companies in Iceland, which operate power-production in volcanic geothermal fields (Landsvirkjun, HS-Orka, OR), committed themselves to drill one deep well each in a field of theirs. &lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;To date two wells have been drilled in the IDDP project. The first one, IDDP-1, was drilled in the Krafla Field, N Iceland, which is operated by Landsvirkjun, and the second well, IDDP-2, was drilled in the Reykjanes Field, which is operated by HS-Orka. The original plan was to drill down to 4-5 km. However, the IDDP-1 in Krafla was drilled into magma of rhyolite composition at the depth of 2.1 km and could therefore not be drilled further. During flow tests, it was flowing superheated steam at high pressure at well head temperature of 450&amp;#176;C. The power capacity was estimated to be 36 MW&lt;sub&gt;e&lt;/sub&gt;. However, due to hostile chemistry of the fluid and damaged casing, the well had to be abandoned and closed after the well tests. IDDP-2 was drilled down to 4,659 m. The highest temperature measured in the bottom of the well was 426&amp;#176;C at a pressure of 340 bar. It was also possible to obtain core samples from the bottom of the well. However, due to damaged casing it hasn't been possible to do further temperature and pressure measurements in the lower parts of IDDP-2. To date flow tests in IDDP-2 have not started.&lt;/span&gt;&lt;/p&gt;&lt;p&gt;&lt;span&gt;The next well in the IDDP project is planned in the Hengill Area. The most promising target is the hot body that started it all in the Nesjavellir Field. According to experience from IDDP-1 and IDDP-2 the main techincal obstacle is the casing. Both wells have serious casing problems. The magma body unexpectedly hit by IDDP-1 illustrated that careful interdisciplinary preperations are needed when drilling into the unknown. Currently, few projects are ongoing to fill the knowledge gaps in order to minimize risk and maximize the probability of successful drilling. &lt;/span&gt;&lt;/p&gt;

scholarly journals Volcanic hydrothermal systems as potential analogues of Martian sulphate-rich terrains

2015 ◽  
Vol 95 (2) ◽  
pp. 153-169 ◽  
Author(s):  
A. Rodríguez ◽  
M.J. van Bergen
Keyword(s):  
Hydrothermal Activity ◽  
Hydrothermal Systems ◽  
Geothermal Systems ◽  
Ambient Conditions ◽  
Flow Paths ◽  
Near Surface ◽  
Mineral Associations ◽  
The Status ◽  
History Of ◽  
Active Processes

AbstractRemote sensing observations and rover missions have documented the presence of sulphate-rich mineral associations on Mars. Many of these minerals are paleo-indicators of hydrous, acidic and oxidising environments that must have prevailed in Mars´ distant past, contrary to the present conditions. Furthermore, occurrences of silica together with high Cl and Br concentrations in Martian soils and rocks represent fingerprints of chemically atypical fluids involved in processes operating on the surface or at shallow depth. From field observations at representative active volcanoes in subduction settings, supported by geochemical modelling, we demonstrate that volcanic hydrothermal systems are capable of producing Mars-like secondary mineral assemblages near lakes, springs and fumaroles through the action of acidic fluids. Water–gas-rock interactions, together with localised flow paths of water and fumarolic gas emitted from associated subaerial vents, lead to deposition of a range of sulphates, including gypsum, jarosite, alunite, epsomite and silica. Evaporation, vapour separation and fluid mixing in (near-) surface environments with strong gradients in temperature and fluid chemistry further promote the diversity of secondary minerals. The mineralogical and chemical marks are highly variable in space and time, being subject to fluctuations in ambient conditions as well as to changes in the status of volcanic-hydrothermal activity. It is concluded that active processes in modern volcanic-geothermal systems may be akin to those that created several of the sulphate-rich terrains in the early history of Mars.

Upper Jurassic travertine at El Macanudo, Argentine Patagonia: a fossil geothermal field modified by hydrothermal silicification and acid overprinting

2017 ◽  
Vol 155 (6) ◽  
pp. 1394-1412 ◽  
Author(s):  
DIEGO M. GUIDO ◽  
KATHLEEN A. CAMPBELL
Keyword(s):  
Hot Spring ◽  
Sedimentary Facies ◽  
Upper Jurassic ◽  
Geothermal Field ◽  
Hydrothermal Systems ◽  
Geothermal Systems ◽  
Volcanic Event ◽  
Exceptional Preservation ◽  
Argentine Patagonia ◽  
Clay Formation

AbstractThe Deseado Massif hosts numerous Late Jurassic (150 Ma) fossil geothermal systems related to an extensive volcanic event developed in a diffuse extensional back-arc setting. Detailed mapping, petrography and mineralogical observations of El Macanudo outcrops verify that it represents a hot-spring-related travertine partially replaced by silica and delineated by six sedimentary facies. These are large concentric cones (F1), laminated vertical columnar structures (F2), porous layers (F3), shrubby and irregular lamination (F4), low-amplitude wavy bedding (F5) and mounds and breccias (F6). The Macanudo Norte Outcrop rocks constitute a silica-replaced travertine sequence, with development of large conical stromatolites in a deep pool or geothermally influenced shallow lacustrine environment, surrounded by a subaerial travertine apron terrace; whereas, the Macanudo Sur Outcrop is a subaerial travertine mound sequence. Structurally controlled vent areas occur in both northern (F1) and southern (F6) outcrops, mainly located along regional NNE- and ENE-trending faults. The other sedimentary units display a concentric distribution of travertine facies with respect to the interpreted vent areas. The El Macanudo palaeo-hot spring deposit is situated in an eroded Jurassic volcanic centre, and records a complex evolutionary-fluid history. The sediments archived three different Jurassic events, when large and long-lasting hydrothermal systems were active across the region. This relative temporal sequence was formed by: (1) travertine precipitation; (2) development of a silica cap, where early silicification was responsible for exceptional preservation of some stromatolitic fabrics; and (3) acid alteration, recorded by dissolution textures and clay formation, and caused by a palaeo-phreatic water-level drop.

Introduction

Geophysics ◽  
1978 ◽  
Vol 43 (7) ◽  
pp. 1449-1449
Author(s):  
George V. Keller
Keyword(s):  
Geothermal Energy ◽  
Hot Springs ◽  
Energy Sources ◽  
Geothermal Systems ◽  
Early Start ◽  
The Past ◽  
New Energy ◽  
The Geysers ◽  
Surface Manifestation ◽  
The U.S

The first exploration for geothermal energy in the U.S. apparently took place during the early 1920s in California and at Yellowstone Park in Wyoming. Despite this early start, by the 1950s, commercially developable geothermal steam had been identified only at one location, The Geysers in California. In the past 10 years, interest in developing geothermal energy has advanced rapidly. Many tens of wildcat wells have been drilled in the search for new energy sources. Many more tens of geothermal prospects are being evaluated. This evaluation of new prospects is beginning to have an impact on the science of geophysical exploration. Some geothermal reservoirs can be located merely by drilling close to thermal manifestations such as geysers and fumiroles. In many other cases, leakage of water in hot springs is far removed from the reservoir in which the hot fluids are present, and it is conceivable that many geothermal systems may exist without any surface manifestation. Development of these more or less hidden geothermal systems will require the services of geologists, geochemists, and geophysicists.

scholarly journals Paleofluid flow: answers in the quartz.

2021 ◽  
Author(s):  
Kevin Freville ◽  
Stanislas Sizaret
Keyword(s):  
Geothermal Energy ◽  
Hydrothermal Systems ◽  
Funding Agency ◽  
Geothermal Systems ◽  
Thermal Anomalies ◽  
Quartz Veins ◽  
Energy Flows ◽  
Attractive Option ◽  
Hydrothermal Fields ◽  
Research Funding Agency

Abstract The search for carbon-free energy sources is at the heart of our concerns. It has become necessary to develop our capacities to harness the active energy flows of our environment while trying to have the lowest possible impact. Among these flows, one of the most stable is that linked to terrestrial thermal anomalies. Geothermal energy is an attractive option due to its regularity and the development of knowledge is encouraged, in France, by the national research funding agency. Geothermal systems are mainly associated with active hydrothermal circulations, fluids can be considered as a source of heat but also of metals. However, fluid circulation within active hydrothermal fields occurs at considerable depths and cannot be observed directly. In this study we propose a method for reconstructing the paleo-flow velocities recorded by quartz. The relative thickness of quartz growth bands is used to deduce the sense and velocity of the paleofluid flow. This contribution highlights the paleofluid flows velocities and the recharge/discharge area in the Limagne Basin geothermal province, which is currently under investigation. Finally, this study provides a tool to be used to study fossil hydrothermal systems containing quartz veins with comb textures.

scholarly journals Nested Shallow Geothermal Systems

2020 ◽  
Vol 12 (12) ◽  
pp. 5152 ◽  
Author(s):  
Alejandro García-Gil ◽  
Miguel Mejías Moreno ◽  
Eduardo Garrido Schneider ◽  
Miguel Ángel Marazuela ◽  
Corinna Abesser ◽  
...  
Keyword(s):  
Geothermal Energy ◽  
Energy Demand ◽  
Data Sets ◽  
Thermal Plume ◽  
Geothermal Systems ◽  
Groundwater Heat Pump ◽  
Energy Governance ◽  
Shallow Geothermal Energy ◽  
Nested System

The long-term sustainability of shallow geothermal systems in dense urbanized areas can be potentially compromised by the existence of thermal interfaces. Thermal interferences between systems have to be avoided to prevent the loss of system performance. Nevertheless, in this work we provide evidence of a positive feedback from thermal interferences in certain controlled situations. Two real groundwater heat pump systems were investigated using real exploitation data sets to estimate the thermal energy demand bias and, by extrapolation, to assess the nature of thermal interferences between the systems. To do that, thermal interferences were modelled by means of a calibrated and validated 3D city-scale numerical model reproducing groundwater flow and heat transport. Results obtained showed a 39% (522 MWh·yr−1) energy imbalance towards cooling for one of the systems, which generated a hot thermal plume towards the downgradient and second system investigated. The nested system in the hot thermal plume only used groundwater for heating, thus establishing a positive symbiotic relationship between them. Considering the energy balance of both systems together, a reduced 9% imbalance was found, hence ensuring the long-term sustainability and renewability of the shallow geothermal resource exploited. The nested geothermal systems described illustrate the possibilities of a new management strategy in shallow geothermal energy governance.

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