Ferruginous Quartzites in the Chopawamsic Terrane, Piedmont Province, Virginia: Evidence for an Ancient Back-Arc Hydrothermal System

2018 ◽  
Vol 113 (2) ◽  
pp. 421-438
Author(s):  
Brent E. Owens ◽  
Bradley J. Peters
Keyword(s):  
Hydrothermal System ◽  
Back Arc ◽  
Ferruginous Quartzites ◽  
Piedmont Province

Boiling vapour-type fluids from the Nifonea vent field (New Hebrides Back-Arc, Vanuatu, SW Pacific): Geochemistry of an early-stage, post-eruptive hydrothermal system

2017 ◽  
Vol 207 ◽  
pp. 185-209 ◽  
Author(s):  
Katja Schmidt ◽  
Dieter Garbe-Schönberg ◽  
Mark D. Hannington ◽  
Melissa O. Anderson ◽  
Benjamin Bühring ◽  
...  
Keyword(s):  
Hydrothermal System ◽  
Early Stage ◽  
Sw Pacific ◽  
New Hebrides ◽  
Back Arc

Noble gas and stable isotope geochemistry of thermal fluids from Deception Island, Antarctica

2009 ◽  
Vol 21 (3) ◽  
pp. 255-267 ◽  
Author(s):  
Minoru Kusakabe ◽  
Keisuke Nagao ◽  
Takeshi Ohba ◽  
Jung Hun Seo ◽  
Sung-Hyun Park ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Hydrothermal System ◽  
Hot Spring ◽  
Isotope Geochemistry ◽  
Noble Gas ◽  
Deception Island ◽  
Rock Interaction ◽  
Thermal Fluids ◽  
Back Arc ◽  
Fumarolic Gas

AbstractNew stable isotope and noble gas data obtained from fumarolic and bubbling gases and hot spring waters sampled from Deception Island, Antarctica, were analysed to constrain the geochemical features of the island's active hydrothermal system and magmatism in the Bransfield back-arc basin. The 3He/4He ratios of the gases (< 9.8 × 10-6), which are slightly lower than typical MORB values, suggest that the Deception Island magma was generated in the mantle wedge of a MORB-type source but the signature was influenced by the addition of radiogenic 4He derived from subducted components in the former Phoenix Plate. The N2/He ratios of fumarolic gas are higher than those of typical mantle-derived gases suggesting that N2 was added during decomposition of sediments in the subducting slab. The δ13C values of -5 to -6‰ for CO2 also indicate degassing from a MORB-type mantle source. The H2/Ar- and SiO2 geothermometers indicate that the temperatures in the hydrothermal system below Deception Island range from ~150°C to ~300°C. The δD and δ18O values measured from fumarolic gas and hot spring waters do not indicate any contribution of magmatic water to the samples. The major ionic components and δD-δ18O-δ34S values indicate that hot spring waters are a mixture of local meteoric water and seawater. Mn and SiO2 in spring waters were enriched relative to seawater reflecting water-rock interaction at depth.

scholarly journals Hydrothermal fields of the Piip submarine volcano, Komandorsky Back-Arc Basin: Chemistry and origin of vent mineralization and bubbling gas

1994 ◽  
Vol 41 ◽  
pp. 55-64
Author(s):  
Pavel V. Torokhov ◽  
Yuri A. Taran
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Isotopic Composition ◽  
Significant Role ◽  
Hydrothermal System ◽  
Submarine Volcano ◽  
Bacterial Sulphate Reduction ◽  
Back Arc ◽  
Hydrothermal Fields

Active thermal vents of the Piip submarine volcano were studied in 1990 from aboard sub­mersibles MIR 1 and 2. Samples of free gas and hydrothermal deposits were collected in the areas of thermal fluid discharge. Mineralogical, isotopic and microprobe studies of samples have shown, as the hydrothermal system cools, the high-temperature anhydrite association displayed at the surface is substituted by calcite-barite and later by calcite-barite-sulfide assemblages. The chemical and isotopic composition of gas and carbonates indicates the significant role of hydrocarbons from the sedimentary layers which, during the low-temperature stage, stimulate the processes of bacterial sulphate reduction. The evolution of a simular hydrothermal system is traced in the Great Caucasus barite deposits.

scholarly journals O SUPERGRUPO RIO DAS VELHAS DA FAIXA MATEUS LEME-PITANGUI - PARTE MERIDIONAL DO CRÁTON DO SÃO FRANCISCO, MG – E SEU SISTEMA DE ALTERAÇÃO HIDROTERMAL

1993 ◽  
Author(s):  
Antônio Wilson Romano
Keyword(s):  
Hydrothermal System ◽  
Sedimentary Rocks ◽  
Upper Proterozoic ◽  
Quadrilátero Ferrífero ◽  
Back Arc ◽  
The Relationship ◽  
High Aluminium ◽  
Mineralogical Assemblage ◽  
Mineralogical Phases ◽  
Deformational Event

The studied area is located at the southern São Francisco Craton, between the northwest comer of the Quadrilátero Ferrífero and the Upper Proterozoic Bambui basin. The region comprises Archaean granite-gneisses and two supracrustal sequences: a) The Archaean Rio das Velhas Supergroup, which consists of a thick sequence of a greenstones associated with metamorphic felsic volcanites, volcano-clastic and sedimentary rocks; and b) the overlying Early Proterozoic Minas Supergroup with its widespread banded iron formations.Two major deformational events are present. The oldest Dn event can be detected only in the Rio das Velhas rocks and produced large folds with mainly E-W trending axis. The latter Dn+1 of Transamazonian age (±2,0 Ga) is a progressive deformational event, that has also affected the Minas Supergroup. It produces NW-SE to NE-SW folds associated to conspicuous planar and linear structures. This event envolved to a NW-vergent thurst system with the development of a strong stretch lineation. This event also produced strike-slip faults interpreted as tear-faults parallel to the direction of the thrusts.This paper deals with the large hydrothermal alteration which has affected the lower volcanoclastics rocks of the Rio das Velhas Supergroup. This alteration has been produced by a solfataric hydrothermal system in mesothermal P-T conditions. It produced a high aluminium mineralogical assemblage of corundum, kyanite (minor andaluzite) and muscovite. This mineralogy is latter retrograde altered to diaspore, pyrophyllite, kaolinite. Minor amounts of tourmaline, rutile, chloritoid are also present. A hydrothermal zoning with three major subdivisions is proposed as follows: high aluminium zone, sericitic (muscovitic) zone and propilitic zone. Some cristallochemical aspects of the mineralogical phases are discussed, and also the origin  of the protolite and the relationship between alteration and deformatiom. The hydrothermal system has evolved under pre to syn tectonic conditions during the Archean Dn tectonism.For this event, a model of collisional tectonics is also proposed for the area, as the Rio das Velhas Supergroup represents a former continental back-arc basin.

scholarly journals Rare Earth Elements in the hydrothermal system at Okinawa Trough back-arc basin

2007 ◽  
Vol 41 (1) ◽  
pp. 1-15 ◽  
Author(s):  
YAYOI HONGO ◽  
HAJIME OBATA ◽  
TOSHITAKA GAMO ◽  
MIWAKO NAKASEAMA ◽  
JUNICHIRO ISHIBASHI ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Hydrothermal System ◽  
Okinawa Trough ◽  
Back Arc
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