Hydrothermal Fluids of Magmatic Origin

Sharma, Rajesh; Srivastava, Pankaj

doi:10.1007/978-3-319-06471-0_9

Cited by 22 publications

(12 citation statements)

References 92 publications

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“…Similarly to CC4‐S, calcite cement CC6 shows a high Mn content (up to 2,644 ppm), which is a key difference with other diagenetic phases described here (Figure ). The origin of a Mn‐rich fluid exclusively affecting the carbonate slivers embedded in the Tazoult core rocks could be associated with: (i) Triassic clayely sediments of the salt wall (Chukhrov, Gorshkov, Rudnitskaya, Beresovskaya, & Sivtsov, ), and (ii) hydrothermal fluids associated with the intrusion of gabbro in the core of the salt wall, as magma partitioning can result in fluids rich in base metals such as Mn (Schindler, Hagemann, Banks, Mernagh, & Harris, ; Sharma & Srivastava, ) (Figure ). Similarly, the fluorite cement that exclusively appears in the Aït bou Oulli Fm.…”

Section: Discussionmentioning

confidence: 99%

Diagenetic evolution of lower Jurassic platform carbonates flanking the Tazoult salt wall (Central High Atlas, Morocco)

et al. 2019

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Platform carbonates diagenesis in salt basins could be complex due to potential alterations of fluids related and non‐related to diapirism. This paper presents the diagenetic history of the Hettangian to Pliensbachian platform carbonates from the Tazoult salt wall area (central High Atlas, Morocco). Low structural relief and outcrop conditions allowed to define the entire diagenetic evolution occurred in the High Atlas diapiric basins since early stages of the diapiric activity up to their tectonic inversion. Precipitation of dolomite and calcite from both warmed marine‐derived and meteoric fluids characterised diagenetic stages during Pliensbachian, when the carbonate platforms were exposed and karstified. Burial diagenesis occurred from Toarcian to Middle Jurassic, due to changes of salt‐induced dynamic related to increase in siliciclastic input, fast diapir rise and rapid burial of Pliensbachian platforms. During this stage, the diapir acted as a physical barrier for fluid circulation between the core and the flanking sediments. In the carbonates and breccias flanking the structures, dolomite and calcite precipitated from basinal brines, whereas carbonate slivers located in the core of the structure, were affected by the circulation of Mn‐rich fluids. The final diagenetic event is characterised by the income of meteoric fluids into the system during uplift caused by Alpine orogeny. These results highlight the relevant influence of diapirism on the diagenetic modifications in salt‐related basins in terms of diagenetic events and involved fluids.

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Section: Discussionmentioning

confidence: 99%

Diagenetic evolution of lower Jurassic platform carbonates flanking the Tazoult salt wall (Central High Atlas, Morocco)

et al. 2019

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“…All these characteristics depict that the fluid evolved from the original H 2 O‐NaCl‐CO 2 ± N 2 system at moderate temperature and variable salinity where H 2 O‐CO 2 ‐rich gaseous fluid evolved to aqueous biphase (H 2 O‐NaCl) and gaseous (CO 2 ) fluid by liquid immiscibility (Figure 11). This lower density fluid immiscibility plays an important role in the exhalation of hydrothermal fluid from the ascending cooling magmatic fluid (Sharma & Srivastava, 2014). The presence of type 3a FI in the late‐stage indicates that at the culmination of the mineralisation, the ore fluid composition changes into the H 2 O‐NaCl dominant fluid.…”

Section: Discussionmentioning

confidence: 99%

“…Water and its vapour, CO 2 , N 2 , SO 2 , H 2 S, CH 4 , CO, HCl, HF, NH 3 , O 2 , Cl are the common and predominant components of the exsolved magmatic fluid. Partition of Cl into the fluid phase increases the salinity of fluid (R. Sharma & Srivastava, 2014). Many metals (Cu, Pb, Zn, W, Mn, Li, etc.)…”

Section: Discussionmentioning

confidence: 99%

Genesis of the late‐stage base metal sulfide mineralisation and its relationship with the regional deformation in Ambaji–Deri, South Delhi Terrane, North‐West India

2022

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Proterozoic stratiform VMS‐type Ambaji–Deri Zn–Pb–Cu deposits in the Aravalli‐Delhi mobile belt of North‐West India are hosted within meta‐sedimentary sequences of the South Delhi Terrane. Several fracture‐filled discordant late‐stage base metal mineralised quartz veins have intruded along with the fractures and foliation at very high Pf (σ2 < Pf < σ1) with typical hydrothermal alteration zones. Temperatures estimated from hydrothermal chlorite vary from 226 to 293°C (mean. 260°C). 40Ar‐39Ar dating of hydrothermal muscovite yielded a plateau age of 625.5 ± 3.3 Ma. Detailed fluid inclusion (FI) analysis reveals three types of primary and four types of secondary FI. Primary H2O‐NaCl‐CO2 ± N2 type 1a FI has medium to high salinity (11.21–21.96 wt% NaCl equivalent) and high density (0.90–1.04 g/cm3), while the secondary type 1b FI with same compositions are characterized by medium salinity (~12.6 wt% NaCl equivalent) and lower density (0.89–0.90 g/cm3). Phase separation/fluid immiscibility is the primary mechanism of mineralisation in the Ambaji–Deri that caused the original fluid to evolve separately as gaseous (CO2) type 2a, b and aqueous type 3a, b (H2O‐NaCl) with similar salinity and density for the aqueous inclusions and low density for the gaseous inclusions (lowering up to 0.58 g/cm3). The ore‐forming fluid with magmatic signatures possibly originated from the cooling G3 granites, remobilized the pre‐existing metals, and precipitated at ~265°C and ~1 kbar at the epizonal depths in the dilated fractures. Later these fluids are mixed with meteoric water and evolved into low saline aqueous fluids that produced supergene alterations.

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“…In the Palai-Islica deposit, the original volcanic apatite reacted with the hydrothermal fluids (in part, magmatic derived [29,39] and potentially F-bearing [49]), driving its composition to higher F content (and lower Cl, OH, and Fe + Mg + Mn contents). Since the ore-fluids and the fluids that produce the hydrothermal alteration are, essentially, the same fluids with complex and evolving physico-chemical characteristics, these modifications of the composition of apatite from hydrothermal alteration are directly related to the intensity of the alteration, that is, the fluid/rock ratios and the thermodynamic constrains.…”

Section: Chemistry Of Apatite Crystals and Their Evolutionmentioning

confidence: 99%

Anion Composition of Apatite in the Au-Cu Epithermal Deposit of Palai-Islica (Almería, SE Spain) as an Indicator of Hydrothermal Alteration

2021

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The Palai-Islica deposit (Almería, SE Spain) is an Au-Cu epithermal deposit hosted in Neogene calc-alkaline andesites and dacites from the Cabo de Gata-Cartagena volcanic belt in the Betic Cordillera. Major element compositions of apatite from Palai-Islica orebody and related hydrothermally altered and unaltered volcanic rock from the region hosting the deposit were obtained to clarify the processes involved in their formation. Apatite in the host volcanic rocks is rich in chlorapatite and hydroxylapatite components (50–57% and 24–36%) and poor in fluorapatite components (12–21%), indicating assimilation processes of cortical Cl-rich material in the magmatic evolution. Apatite in the orebody sometimes has corrosion textures and is mostly fluorapatite (94–100%). Apatite from the hydrothermally altered host rock of the orebody systematically bears signs of corrosion and has variable and intermediate fluorapatite (19–100%), chlorapatite (1–50%), and hydroxylapatite (0–47%) components. The style of zonation and the composition are related to the proximity to the orebody. These features can be interpreted as the result of hydrothermal modification of high Cl, OH-rich volcanic apatites into F-rich apatites. The enrichment of F is related to the intensity of hydrothermal alteration and could therefore constitute a geochemical index of alteration and of mineralization processes.

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Hydrothermal Fluids of Magmatic Origin

Cited by 22 publications

References 92 publications

Diagenetic evolution of lower Jurassic platform carbonates flanking the Tazoult salt wall (Central High Atlas, Morocco)

Diagenetic evolution of lower Jurassic platform carbonates flanking the Tazoult salt wall (Central High Atlas, Morocco)

Genesis of the late‐stage base metal sulfide mineralisation and its relationship with the regional deformation in Ambaji–Deri, South Delhi Terrane, North‐West India

Anion Composition of Apatite in the Au-Cu Epithermal Deposit of Palai-Islica (Almería, SE Spain) as an Indicator of Hydrothermal Alteration

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