scholarly journals Seawater-rock interaction at Ushishir volcano-hydrothermal system, Kuril Islands

2019 ◽  
Vol 98 ◽  
pp. 01049
Author(s):  
Yuri Taran ◽  
Elena Kalacheva
Keyword(s):  
Hydrothermal System ◽  
Total Mass ◽  
Boron Concentration ◽  
Hydrothermal Activity ◽  
Hydrothermal Fluids ◽  
Heat Output ◽  
Rock Interaction ◽  
Oxygen Isotopic ◽  
High Boron ◽  
Significant Uptake

Ushishir volcano is located in the middle of the Kuril Arc. The Ushishir crater, a closed bay connected with the ocean by a narrow and shallow strait is characterized by a strong hydrothermal activity. Boiling springs, hot pools, fumaroles and shallow submarine vents are manifestations of a magmatic-seawater hydrothermal system with the discharging solution similar in chemical and isotopic composition to the seafloor hydrothermal fluids. The main features of the Ushishir fluids are: (1) water has close to zero δD and a large oxygen isotopic shift (6 7‰); (2) high boron concentration (~70 ppm); (3) a significant uptake of Ca and Sr from the rock and Ca/Sr higher than that for seawater with 87Sr/86Sr ~0.7037, a bit higher than the rock value (0.7032). The measured onshore discharge of boiling water is ~ 5 kg/s; however, a large plume of the discoloured seawater releasing from the outer submarine slope of the volcano indicates a much higher total mass and heat output.

scholarly journals Source Analysis of Silicon and Uranium in uranium-rich shale in the Xiuwu Basin, Southern China

2019 ◽  
Vol 11 (1) ◽  
pp. 89-100
Author(s):  
Zhuo Li ◽  
Kun Zhang ◽  
Yan Song ◽  
Xiaoxue Liu ◽  
Zhenxue Jiang ◽  
...  
Keyword(s):  
Lower Cambrian ◽  
Southern China ◽  
Isotopic Analysis ◽  
Hydrothermal Activity ◽  
Hydrothermal Fluids ◽  
Source Analysis ◽  
Uranium Deposits ◽  
Uranium Enrichment ◽  
Element Analysis ◽  
Oxygen Isotopic

Abstract Uranium deposits are crucial resources for the development of the nuclear energy. Among known sources of uranium, the uranium-rich shales have recently obtained significance. In this paper, the Lower Cambrian Wangyinpu Formation shale in the Xiuwu Basin, southern China, has been studied using a combination of techniques including element analysis (Al, Fe, and Mn), δ30Si silicon isotopic analysis, δ18O oxygen isotopic analysis, study of core samples. It has been observed that significant hydrothermal activity occurred in the Xiuwu Basin during the Early Cambrian period. The results show that 20%–40% of the silicon in most of the sections of the Lower Cambrian Wangyinpu Formation were inherited from the hydrothermal fluids, with temperatures ranging between 75∘C and 102∘C. It is concluded that more than 90% of the uranium in most of the sections of the Lower Cambrian Wangyinpu shale was derived from submarine hydrothermal fluids, while less than 10% from the terrigenous detritus. The enrichment of uranium in the basin was observed in the Middle-Upper part of the Wangyinpu Formation and the geological resources estimated to a tune of ~4.9×103 t. In this paper, we proposed a model for silicon and uranium enrichment in the Lower Cambrian shale controlled by hydrothermal activity in the Xiuwu Basin. This model also provides a scientific rationale for uranium further exploration and exploitation of the uranium resource.

scholarly journals Rolling Ironstones from Earth and Mars: Terrestrial Hydrothermal Ooids as a Potential Analogue of Martian Spherules

Minerals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 460
Author(s):  
Marcella Di Bella ◽  
Franco Pirajno ◽  
Giuseppe Sabatino ◽  
Simona Quartieri ◽  
Roberto Barbieri ◽  
...  
Keyword(s):  
High Resolution ◽  
Volcanic Activity ◽  
Hydrothermal System ◽  
Mineralogical Composition ◽  
Hydrothermal Activity ◽  
Hydrothermal Fluids ◽  
Cause Of Formation ◽  
The Earth ◽  
High Resolution Images ◽  
Iron Ooids

High-resolution images of Mars from National Aeronautics and Space Administration (NASA) rovers revealed mm-size loose haematite spherulitic deposits (nicknamed “blueberries”) similar to terrestrial iron-ooids, for which both abiotic and biotic genetic hypotheses have been proposed. Understanding the formation mechanism of these haematite spherules can thus improve our knowledge on the possible geologic evolution and links to life development on Mars. Here, we show that shape, size, fabric and mineralogical composition of the Martian spherules share similarities with corresponding iron spherules currently forming on the Earth over an active submarine hydrothermal system located off Panarea Island (Aeolian Islands, Mediterranean Sea). Hydrothermal fluids associated with volcanic activity enable these terrestrial spheroidal grains to form and grow. The recent exceptional discovery of a still working iron-ooid source on the Earth provides indications that past hydrothermal activity on the Red Planet is a possible scenario to be considered as the cause of formation of these enigmatic iron grains.

Magnetite texture and trace-element geochemistry fingerprint of pulsed mineralization in the Xinqiao Cu-Fe-Au deposit, Eastern China

2020 ◽  
Vol 105 (11) ◽  
pp. 1712-1723
Author(s):  
Yu Zhang ◽  
Pete Hollings ◽  
Yongjun Shao ◽  
Dengfeng Li ◽  
Huayong Chen ◽  
...  
Keyword(s):  
Trace Element ◽  
Triple Junction ◽  
Eastern China ◽  
Black Shales ◽  
Hydrothermal Fluids ◽  
Oscillatory Zoning ◽  
Trace Element Geochemistry ◽  
Element Geochemistry ◽  
Rock Interaction ◽  
Multiple Pulses

Abstract The origin of stratabound deposits in the Middle-Lower Yangtze River Valley Metallogenic Belt (MLYRB), Eastern China, is the subject of considerable debate. The Xinqiao Cu-Fe-Au deposit in the Tongling ore district is a typical stratabound ore body characterized by multi-stage magnetite. A total of six generations of magnetite have been identified. Mt1 is commonly replaced by porous Mt2, and both are commonly trapped in the core of Mt3, which is characterized by both core-rim textures and oscillatory zoning. Porous Mt4 commonly truncates the oscillatory zoning of Mt3, and Mt5 is characterized by 120° triple junction texture. Mt1 to Mt5 are commonly replaced by pyrite that coexists with quartz, whereas Mt6, with a fine-grained foliated and needle-like texture, commonly cuts the early pyrite as veins and is replaced by pyrite that coexists with calcite. The geochemistry of the magnetite suggests that they are hydrothermal in origin. The microporosity of Mt2 and Mt4 magnetite, their sharp contacts with Mt1 and Mt3, and lower trace-element contents (e.g., Si, Ca, Mg, and Ti) than Mt1 and Mt3 suggest that they formed via coupled dissolution and reprecipitation of the precursor Mt1 and Mt3 magnetite, respectively. This was likely caused by high-salinity fluids derived from intensive water-rock interaction between the magmatic-hydrothermal fluids associated with the Jitou stock and Late Permian metalliferous black shales. The 120° triple junction texture of Mt5 suggests it is the result of fluid-assisted recrystallization, whereas Mt6 formed by replacement of hematite as a result of fracturing. The geochemistry of the magnetite suggests that the temperature increased from Mt2 to Mt3 and implies that there were multiple pulses of fluids from a magmatic-hydrothermal system. Therefore, we propose that the Xinqiao stratiform mineralization was genetically associated with multiple influxes of magmatic hydrothermal fluids derived from the Early Cretaceous Jitou stock. This study demonstrates that detailed texture examination and in situ trace-elements analysis under robust geological and petrographic frameworks can effectively constrain the mineralization processes and ore genesis.

scholarly journals Analysis of Hydrothermal Systems Beneath Tayukeng through Long-Term Geochemical Signals of Hydrothermal Fluids in Tatun Volcano Group, Taiwan

2021 ◽  
Vol 18 (14) ◽  
pp. 7411
Author(s):  
Hsin-Fu Yeh ◽  
Hung-Hsiang Hsu
Keyword(s):  
Surface Temperature ◽  
Hydrothermal System ◽  
Hydrothermal Fluid ◽  
Thermal Water ◽  
Hydrothermal Systems ◽  
Hydrothermal Fluids ◽  
Geochemical Variations ◽  
Northern Taiwan

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.

Magmatic-Hydrothermal Mineralization Processes at the Yidong Tin Deposit, South China: Insights from In Situ Chemical and Boron Isotope Changes of Tourmaline

2021 ◽  
Author(s):  
He-Dong Zhao ◽  
Kui-Dong Zhao ◽  
Martin R. Palmer ◽  
Shao-Yong Jiang ◽  
Wei Chen
Keyword(s):  
South China ◽  
Hydrothermal Fluids ◽  
Boron Isotope ◽  
Granitic Magma ◽  
Gangue Mineral ◽  
Rock Interaction ◽  
Hydrothermal Mineralization ◽  
Mineralization Processes ◽  
Tin Deposit

Abstract Owing to the superimposition of water-rock interaction and external fluids, magmatic source signatures of ore-forming fluids for vein-type tin deposits are commonly overprinted. Hence, there is uncertainty regarding the involvement of magmatic fluids in mineralization processes within these deposits. Tourmaline is a common gangue mineral in Sn deposits and can crystallize from both the magmas and the hydrothermal fluids. We have therefore undertaken an in situ major, trace element, and B isotope study of tourmaline from the Yidong Sn deposit in South China to study the transition from late magmatic to hydrothermal mineralization. Six tourmaline types were identified: (1) early tourmaline (Tur-OE) and (2) late tourmaline (Tur-OL) in tourmaline-quartz orbicules from the Pingying granite, (3) early tourmaline (Tur-DE) and (4) late tourmaline (Tur-DL) in tourmaline-quartz dikelets in the granite, and (5 and 6) core (Tur-OC) and rim (Tur-OR), respectively of hydrothermal tourmaline from the Sn ores. Most of the tourmaline types belong to the alkali group and the schorl-dravite solid-solution series, but the different generations of magmatic and hydrothermal tourmaline are geochemically distinct. Key differences include the hundredfold enrichment of Sn in hydrothermal tourmaline compared to magmatic tourmaline, which indicates that hydrothermal fluids exsolving from the magma were highly enriched in Sn. Tourmaline from the Sn ores is enriched in Fe3+ compared to the hydrothermal tourmaline from the granite and displays trends of decreasing Al and increasing Fe content from core to rim, relating to the exchange vector Fe3+Al–1. This reflects oxidation of fluids during the interaction between hydrothermal fluids and the mafic-ultramafic wall rocks, which led to precipitation of cassiterite. The hydrothermal tourmaline has slightly higher δ11B values than the magmatic tourmaline (which reflects the metasedimentary source for the granite), but overall, the tourmaline from the ores has δ11B values similar to those from the granite, implying a magmatic origin for the ore-forming fluids. We identify five stages in the magmatic-hydrothermal evolution of the system that led to formation of the Sn ores in the Yidong deposit based on chemical and boron isotope changes of tourmaline: (1) emplacement of a B-rich, S-type granitic magma, (2) separation of an immiscible B-rich melt, (3) exsolution of an Sn-rich, reduced hydrothermal fluid, (4) migration of fluid into the country rocks, and (5) acid-consuming reactions with the surrounding mafic-ultramafic rocks and oxidation of the fluid, leading to cassiterite precipitation.

Variation in kaolinite morphology with growth temperature in isotopically mixed pore-fluids, Brent Group, UK North Sea

Clay Minerals ◽  
1994 ◽  
Vol 29 (4) ◽  
pp. 591-608 ◽  
Author(s):  
M. Osborne ◽  
R. S. Haszeldine ◽  
A. E. Fallick
Keyword(s):  
Meteoric Water ◽  
Pore Space ◽  
Pore Waters ◽  
The West ◽  
Rock Interaction ◽  
Isotopic Studies ◽  
Reservoir Sandstones ◽  
Oxygen Isotopic ◽  
Low Degrees ◽  
Water Rock Interaction

AbstractDiagenetic kaolinite in reservoir sandstones of the Brent Group precipitated following the dissolution of detrial feldspar. Two distinct morphologies of kaolinite occur: (1) early diagenetic vermiform kaolinite which is often associated with expanded detrital micas; (2) later diagenetic ‘blocky’ kaolinite. Combined hydrogen and oxygen isotopic studies suggest that vermiform kaolinite precipitated at 25–50°C, and blocky kaolinite at 50–80°C, from pore-waters of a similar isotopic composition (δ18O = −6.5 to −3.5‰). These pore-waters are interpreted to be either a mixture of meteoric and compactional waters, or alternatively a meteoric water that had evolved isotopically due to water-rock interaction. Kaolinite precipitation occurred predominantly during the late Cretaceous to early Eocene. Influx of meteoric water into the Brent Group, probably occurred during the Palaeocene. Fluid flow across the entire basin was driven by a hydrostatic head on the East Shetland Platform palaeo-landmass to the west. The development of the two kaolinite morphologies is possibly related to the degree of supersaturation at the time of precipitation. At low degrees of supersaturation, vermiform kaolinite precipitated slowly upon detrital mica surfaces. Blocky kaolinite precipitated more rapidly into open pore-space at higher degrees of supersaturation. Precipitation of blocky kaolinite was perhaps triggered by the decay of oxalate.

scholarly journals Surface and Groundwater Hydrochemistry of the Menengai Caldera Geothermal Field and Surrounding Nakuru County, Kenya

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3131 ◽  
Author(s):  
Nelly Montcoudiol ◽  
Neil M. Burnside ◽  
Domokos Györe ◽  
Nicholas Mariita ◽  
Thecla Mutia ◽  
...  
Keyword(s):  
Ionic Composition ◽  
Sampling Period ◽  
Geothermal Field ◽  
Wet Season ◽  
Lake Nakuru ◽  
Rock Interaction ◽  
Geothermal Wells ◽  
Groundwater Hydrochemistry ◽  
Hydrological System ◽  
Oxygen Isotopic

In order to assess the sustainability and impact of production from geothermal reservoirs on hydrological systems, a thorough understanding of local and regional hydrogeological systematics is a prerequisite. The Menengai Caldera in the Kenya Great Rift Valley is one of the largest explored geothermal fields in the country. This paper presents a hydrochemical investigation of the Menengai Caldera geothermal field and the ground and surface waters of the surrounding Nakuru County. Our results demonstrated a similar, sodium-alkaline dominated, ionic composition across all water types. Geothermal wells return the highest cation/anion concentrations and largely demonstrate a meteoric source from their δ18O and δ2H signature. Wells MW-09 (central part of the caldera), MW-18 (eastern part) and MW-20 (central part) showed a more evaporitic signature, closely matching with our own calculated Lake Evaporation Line, suggesting an increased mixing influence of Lake Nakuru waters. MW-09 also showed evidence of high-temperature oxygen isotopic exchange and significant water-rock interaction. Lake samples largely demonstrated seasonal shifts in ionic and isotopic values. Lake Nakuru ionic composition and isotopic values increased throughout the 12-month wet–dry–wet season sampling period. This correlated with a decrease in area which suggests a lessening of water inflow and facilitates increased evaporation. Groundwaters demonstrated clear evidence of mixing between meteoric, irrigation and lake waters. These observations enhanced the understanding of the hydrological system surrounding the Menengai Caldera and, when combined with future studies, will provide a powerful tool to assess the sustainability and impact of soon-to-be completed geothermal power production operations.

scholarly journals Shallow Magmatic Hydrothermal Eruption in April 2018 on Ebinokogen Ioyama Volcano in Kirishima Volcano Group, Kyushu, Japan

Geosciences ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 183 ◽  
Author(s):  
Yasuhisa Tajima ◽  
Setsuya Nakada ◽  
Fukashi Maeno ◽  
Toshio Huruzono ◽  
Masaaki Takahashi ◽  
...  
Keyword(s):  
Hydrothermal System ◽  
Hydrothermal Activity ◽  
Volcanic Field ◽  
Multiple Systems ◽  
Geothermal Activity ◽  
Hydrothermal Eruption ◽  
Kirishima Volcano ◽  
Geophysical Observation ◽  
Under The Volcano ◽  
Fluid Pressurization

The Kirishima Volcano Group is a volcanic field ideal for studying the mechanism of steam-driven eruptions because many eruptions of this type occurred in the historical era and geophysical observation networks have been installed in this volcano. We made regular geothermal observations to understand the hydrothermal activity in Ebinokogen Ioyama Volcano. Geothermal activity resumed around the Ioyama from December 2015. A steam blowout occurred in April 2017, and a hydrothermal eruption occurred in April 2018. Geothermal activity had gradually increased before these events, suggesting intrusion of the magmatic component fluids in the hydrothermal system under the volcano. The April 2018 eruption was a magmatic hydrothermal eruption caused by the injection of magmatic fluids into a very-shallow hydrothermal system as a bottom–up fluid pressurization, although juvenile materials were not identifiable. Additionally, the upwelling of mixed magma–meteoric fluids to the surface as a kick was observed just before the eruption to cause the top–down flashing of April 2018. A series of events was generated in the shallower hydrothermal regime consisting of multiple systems divided by conductive caprock layers.

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