Alteration and Mineralization Products of the Zannone Giant Pockmark (Zannone Hydrothermal Field, Central Tyrrhenian Sea)

The Zannone Giant Pockmark (ZGP) is a shallow-water (<−150 m) giant depression located on the shelf off Zannone Island (Pontine Archipelago, central Tyrrhenian Sea, Italy), hosting active hydrothermal vents. The ZGP seabed displays different fluid-venting morphologies (pockmarks, lithified pavements, mounds, and cone-shaped structures) and widespread bacterial communities. In this study, we analyzed ROV (Remote Operated Vehicle) images to gain information on seabed geology and the textural, mineralogical, and geochemical composition of authigenic crusts and gravel-sized clasts sampled close to active emissions. ROV images show authigenic dome-shaped crusts composed of native sulfur associated with barite, gypsum, amorphous silica, and secondary hydrothermal minerals (illite–montmorillonite). The gravel-sized clasts are mostly rhyolites strongly affected by hydrothermal alteration (Alteration Index > 88; depletion of some mobile elements and enrichment of some base metals), causing feldspar-destruction, silicification, formation of hydrothermal phyllosilicates, and precipitation of disseminated pyrite. More intense alteration implying the complete obliteration of the primary mineralogy or fabric is represented by quartz-pyrite samples. ZGP seabed morphology and petro-geochemical features of deposits point to the possible occurrence of a sulfide system linked to the degassing of magma similar to that feeding the Pleistocene products of Ponza Island.

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Ultra-small cells and DPANN genome unveiled inside an extinct vent chimney

10.1101/2021.03.08.430540 ◽

2021 ◽

Author(s):

Hinako Takamiya ◽

Mariko Kouduka ◽

Hitoshi Furutani ◽

Hiroki Mukai ◽

Takushi Yamamoto ◽

...

Keyword(s):

Nucleic Acids ◽

Grain Boundaries ◽

Deep Sea ◽

Hydrothermal Vents ◽

Single Gene ◽

Metal Sulfide ◽

Small Cells ◽

Acid Fermentation ◽

Microbial Life ◽

Fluid Venting

AbstractChemosynthetic organisms flourish around deep-sea hydrothermal vents where energy-rich fluids are emitted from metal sulfide chimneys. In contrast to actively venting chimneys, the nature of microbial life in extinct chimneys without fluid venting remains largely unknown. Here, the occurrence of ultra-small cells in silica-filled grain boundaries inside an extinct chimney is demonstrated by high-resolution bio-signature mapping. The ultra-small cells are associated with extracellularly precipitated Cu2O nanocrystals. Single-gene analysis shows that the chimney interior is dominated by a member of Pacearchaeota known as a major phylum of DPANN. Genome-resolved metagenomic analysis reveals that the chimney Pacearchaeota member is equipped with a nearly full set of genes for fermentation-based energy generation from nucleic acids, in contrast to previously characterized Pacearchaeota members lacking many genes for nucleic acid fermentation. We infer that the ultra-small cells associated with silica and extracellular Cu2O nanocrystals in the grain boundaries are Pacearchaeota, on the basis of the experimentally demonstrated capability of silica to concentrate nucleic acids from seawater and the presence of Cu-exporting genes in a reconstructed Pacearchaeota genome. Given the existence of ~3-billion-year-old submarine hydrothermally deposited silica, proliferation of microbial life using silica-bound nucleic acids might be relevant to the primitive vent biosphere.

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The synthesis of highly dispersed noble and base metals on silica via strong electrostatic adsorption: I. Amorphous silica

Journal of Catalysis ◽

10.1016/j.jcat.2008.09.022 ◽

2008 ◽

Vol 260 (2) ◽

pp. 329-341 ◽

Cited By ~ 145

Author(s):

Ling Jiao ◽

John R. Regalbuto

Keyword(s):

Amorphous Silica ◽

Base Metals ◽

Electrostatic Adsorption ◽

Strong Electrostatic Adsorption ◽

Highly Dispersed

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Hydrothermal Alteration and Mineralization of the Randu Kuning Porphyry Cu-Au and Intermediate Sulphidation Epithermal Au-Base Metals Deposits in Selogiri, Central Java, Indonesia

Journal of Applied Geology ◽

10.22146/jag.26951 ◽

2016 ◽

Vol 1 (1) ◽

pp. 1

Author(s):

Sutarto Sutarto ◽

Arifudin Idrus ◽

Agung Harijoko ◽

Lucas Donny Setijadji ◽

Franz Michael Meyer ◽

...

Keyword(s):

Hydrothermal Alteration ◽

Carbonate Rocks ◽

Base Metals ◽

Porphyry Cu ◽

Central Java ◽

Copper Gold ◽

Volcaniclastic Rocks ◽

Gold Grade ◽

Epithermal Au ◽

Yogyakarta City

The Randu Kuning Porphyry Cu-Au prospect area is situated in the Selogiri district, Wonogiri regency, Central Java, Indonesia, about 40 km to the South-East from Solo city, or approximately 70 km east of Yogyakarta city. The Randu Kuning area and its vicinity is a part of the East Java Southern Mountain Zone, mostly occupied by both plutonic and volcanic igneous rocks, volcaniclastic, silisiclastic and carbonate rocks. Magmatism-volcanism products were indicated by the abundant of igneous and volcaniclastic rocks of Mandalika and Semilir Formation. The Alteration zones distribution are generally controlled by the NE–SW and NW–SE trending structures. At least eight types of hydrothermal alteration at the Randu Kuning area and its vicinity had been identified, i.e. magnetite + biotite ± K-feldspar ± chlorite (potassic), chlorite + sericite + magnetite ± actinolite, chlorite + magnetite ± actinolite ± carbonate (inner propylitic), chlorite + epidote ± carbonate (outer propylitic), sericite + quartz + pyrite (phyllic), illite + kaolinite ± smectite (intermediate argillic), illite + kaolinite ± pyrophyllite ± alunite (advanced argillic) and quatz + chlorite (sillisic) zones. The Randu Kuning mineralization at Selogiri is co existing with the porphyry Cu-Au and intermediate sulphidation epithermal Au-base metals. Mineralization in the porphyry environment is mostly associated with the present of quartz-sulphides veins including AB, C, carbonate-sulphides veins (D vein) as well as disseminated sulphides. While in the epithermal prospect, mineralization is particularly associated with pyrite + sphalerite + chalcopyrite + carbonate ± galena veins as well as hydrothermal breccias. The Randu Kuning porphyry prospect has copper gold grade in range at about 0.66–5.7 gr/t Au and 0.04–1.24 % Cu, whereas in the intermediate sulphidation epithermal contain around 0.1–20.8 gr/t Au, 1.2–28.1 gr/t Ag, 0.05–0.9 % Zn, 0.14–0.59 % Pb and 0.01–0.65 % Cu.

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Hydrochemical mercury distribution and air-sea exchange over the submarine hydrothermal vents off-shore Panarea Island (Aeolian arc, Tyrrhenian Sea)

Marine Chemistry ◽

10.1016/j.marchem.2017.04.003 ◽

2017 ◽

Vol 194 ◽

pp. 63-78 ◽

Cited By ~ 10

Author(s):

E. Bagnato ◽

E. Oliveri ◽

A. Acquavita ◽

S. Covelli ◽

E. Petranich ◽

...

Keyword(s):

Hydrothermal Vents ◽

Tyrrhenian Sea ◽

Mercury Distribution ◽

Aeolian Arc

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A numerical approach for the formation of chlorite and sulphide-bearing greisen: a study based on the Navalcubilla system (Spanish Central System)

Mineralogical Magazine ◽

10.1180/minmag.1997.061.408.03 ◽

1997 ◽

Vol 61 (408) ◽

pp. 639-654

Author(s):

Fernando Tornos

Keyword(s):

Hydrothermal Alteration ◽

Granitic Rock ◽

Numerical Approach ◽

Base Metals ◽

Central System ◽

Temperature Changes ◽

Ore Minerals ◽

Acid Fluid ◽

High Concentrations ◽

Spanish Central System

AbstractThe formation of sulphide and cassiterite-bearing chlorite-rich greisens in the Navalcubilla granite has been modelled theoretically. Numerical simulation on the reaction of a hydrothermal fluid with a granitic rock predicts assemblages very similar to those found in nature, with progressive formation of muscovite, quartz, chlorite, microcline and plagioclase zones. The hydrothermal alteration of the rock produces a neutralization of the inflowing acid fluid, a drop in the fS2 and, to a lesser degree, an increment in fO2. During hydrothermal alteration, fS2 and fO2 change abruptly between metasomatic zones, but chlorite seems to control their major changes. Scheelite and cassiterite are concentrated in the internal zones, while sulphides are related to the more external zones. Fluid-rock reactions seem to be very effective for precipitating cassiterite and scheelite, even from very Sn and W-poor fluids. Appreciable amounts of sulphides are only expected in systems with high concentrations of base metals. Boiling and simple cooling of the fluids acidifies and oxidizes them but chemical changes are not strong enough to induce significant precipitation of ore minerals, at least when the temperature changes are small. Continued circulation of fluids along fractures with previously precipitated quartz + wolframite produces replacement of wolframite by scheelite and sulphides.

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Characterization of Bacterial Communities in Deep-Sea Hydrothermal Vents from Three Oceanic Regions

Marine Biotechnology ◽

10.1007/s10126-015-9683-3 ◽

2015 ◽

Vol 18 (2) ◽

pp. 232-241 ◽

Cited By ~ 13

Author(s):

Tianliang He ◽

Xiaobo Zhang

Keyword(s):

Deep Sea ◽

Bacterial Communities ◽

Hydrothermal Vents

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Diversity of Total Bacterial Communities and Chemoautotrophic Populations in Sulfur-Rich Sediments of Shallow-Water Hydrothermal Vents off Kueishan Island, Taiwan

Microbial Ecology ◽

10.1007/s00248-016-0898-2 ◽

2016 ◽

Vol 73 (3) ◽

pp. 571-582 ◽

Cited By ~ 4

Author(s):

Li Wang ◽

Man Kit Cheung ◽

Rulong Liu ◽

Chong Kim Wong ◽

Hoi Shan Kwan ◽

...

Keyword(s):

Shallow Water ◽

Bacterial Communities ◽

Hydrothermal Vents

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Comparison of Different Algorithms to Map Hydrothermal Alteration Zones Using ASTER Remote Sensing Data for Polymetallic Vein-Type Ore Exploration: Toroud–Chahshirin Magmatic Belt (TCMB), North Iran

Remote Sensing ◽

10.3390/rs11050495 ◽

2019 ◽

Vol 11 (5) ◽

pp. 495 ◽

Cited By ~ 19

Author(s):

Lida Noori ◽

Amin Pour ◽

Ghasem Askari ◽

Nader Taghipour ◽

Biswajeet Pradhan ◽

...

Keyword(s):

Remote Sensing ◽

Hydrothermal Alteration ◽

Remote Sensing Data ◽

Base Metals ◽

Argillic Alteration ◽

Mineral Assemblages ◽

Vein Type ◽

North Of Iran ◽

Advanced Argillic Alteration ◽

Hydrothermal Alteration Zones

Polymetallic vein-type ores are important sources of precious metal and a principal type of orebody for various base-metals. In this research, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) remote sensing data were used for mapping hydrothermal alteration zones associated with epithermal polymetallic vein-type mineralization in the Toroud–Chahshirin Magmatic Belt (TCMB), North of Iran. The TCMB is the largest known goldfield and base metals province in the central-north of Iran. Propylitic, phyllic, argillic, and advanced argillic alteration and silicification zones are typically associated with Au-Cu, Ag, and/or Pb-Zn mineralization in the TCMB. Specialized image processing techniques, namely Selective Principal Component Analysis (SPCA), Band Ratio Matrix Transformation (BRMT), Spectral Angle Mapper (SAM) and Mixture Tuned Matched Filtering (MTMF) were implemented and compared to map hydrothermal alteration minerals at the pixel and sub-pixel levels. Subtle differences between altered and non-altered rocks and hydrothermal alteration mineral assemblages were detected and mapped in the study area. The SPCA and BRMT spectral transformation algorithms discriminated the propylitic, phyllic, argillic and advanced argillic alteration and silicification zones as well as lithological units. The SAM and MTMF spectral mapping algorithms detected spectrally dominated mineral groups such as muscovite/montmorillonite/illite, hematite/jarosite, and chlorite/epidote/calcite mineral assemblages, systematically. Comprehensive fieldwork and laboratory analysis, including X-ray diffraction (XRD), petrographic study, and spectroscopy were conducted in the study area for verifying the remote sensing outputs. Results indicate several high potential zones of epithermal polymetallic vein-type mineralization in the northeastern and southwestern parts of the study area, which can be considered for future systematic exploration programs. The approach used in this research has great implications for the exploration of epithermal polymetallic vein-type mineralization in other base metals provinces in Iran and semi-arid regions around the world.

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