Geochemistry of the alteration pipe at the Amulet Upper A deposit, Noranda, Quebec

1982 ◽  
Vol 19 (11) ◽  
pp. 2060-2084 ◽  
Author(s):  
B. V. Hall
Keyword(s):  
Hydrothermal Alteration ◽  
Sampling Procedure ◽  
Contact Metamorphism ◽  
Dominant Factor ◽  
Hydrothermal Solutions ◽  
Zinc Deposit ◽  
Pillow Lavas ◽  
Sample Position ◽  
Copper Zinc ◽  
Massive Sulphides

The Amulet Upper A orebody is a stratiform pyritiferous copper–zinc deposit situated within a sequence of andesitic pillow lavas. Underlying the massive sulphides is a cylindrical alteration pipe containing sulphides plus cordierite–anthophyllite-bearing rock. Hydrothermal alteration considered coincident with the formation of the overlying massive sulphides resulted in the development of a chlorite–quartz assemblage occupying the center of the alteration pipe, with a sericite–epidote–quartz assemblage at the fringes. Contact metamorphism resulting from the intrusion of the Lac Dufault granodiorite isochemically transformed the chlorite–quartz assemblage to cordierite–anthophyllite, and the sericite–epidote–quartz assemblage to biotite–epidote–quartz. This caused the development of four mineralogical zones within the alteration pipe: (1) anthophyllite zone, (2) cordierite zone, (3) biotite zone, and (4) stockwork zone.Pillows within the alteration pipe and exterior to it were studied using whole-rock analyses. A statistically balanced sampling procedure was adopted such that chemical and mineralogical variations within a single pillow could be compared with variations between adjacent pillows and finally with pillows situated in different locations within the deposit area. The largest source of variation was found to be a function of sample position within the alteration pipe. Ancillary variations include: (1) variations on the scale of an individual pillow resulting from the inward penetration of hydrothermal solutions and (2) variations between adjacent pillows due to differing degrees of alteration and veining.Proceeding into the alteration pipe, CaO, Na2O, Ba, Cr, Ni, and Sr were removed, Fe2O3T, MgO, K2O, H2O+, S2−, Cd, Cu, Li, and Zn were added, and Al2O3, TiO2, and V remained relatively constant. These changes were largely a chemical manifestation of the introduction of sulphides, plus the breakdown of plagioclase and pyroxene to form chlorite and quartz in the center of the alteration pipe, and sericite, epidote, and quartz at the fringes. Temperature appears to have been the dominant factor in controlling the distribution of the alteration assemblages, although sulphur fugacity did have an effect on the sulphide assemblages.

The Sherritt-Gordon copper-zinc deposit, northern Manitoba

1929 ◽  
Vol 24 (5) ◽  
pp. 457-469 ◽  
Author(s):  
Everend Lester Bruce
Keyword(s):  
Zinc Deposit ◽  
Copper Zinc

The event geological maps: a new predictive tool to identify potential NOA (Naturally Occurring Asbestos) lithologies, Example from the Pyrenees (France).

2020 ◽  
Author(s):  
Florence Cagnard ◽  
Didier Lahondère ◽  
Benjamin Le Bayon ◽  
Aurore Hertout ◽  
Thierry Baudin ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Regional Metamorphism ◽  
Contact Metamorphism ◽  
Natural Environments ◽  
Field Observations ◽  
Predictive Tool ◽  
Naturally Occurring ◽  
Geological Maps ◽  
Naturally Occurring Asbestos ◽  
Geological Event

<p>The event geological maps consist in innovative numerical maps that were just designed and produced for the first time, as part of the RGF (“French Geological Referential”) mapping program in the Pyrenees. Rocks acquire their mineralogical, structural and textural characteristics through a complex geological history reflecting successive stages of transformation (i.e. metamorphism, deformation, alteration…), so called “geological events”. Classical geological maps can only represent some of these events.  In the Pyrenean orogenic belt, which results from a polyphase tectono-metamorphic history over 600 Ma (from Precambrian to present), 3400 geological events were identified. Such geological events were classified by types (e.g. deposit, volcanism, intrusion, metamorphism, weathering, hydrothermal alteration…) and time periods. They were referenced into a database and associated to mapped features (120,000 polygons and lines), coming from a compilation of 60 geological maps at 1: 50,000 scale.</p><p>In the Pyrenees, Naturally Occurring Asbestos (NOA) mostly occur in specific lithologies such as ultrabasic, basic and intermediate plutonic rocks, and meta-limestones. These rocks may be affected by different metamorphic events (i.e. hydrothermal alteration, greenschist and/or HT-LP regional metamorphism, contact metamorphism). We performed a GIS treatment to produce a predictive map of potential NOA hosting lithologies. This treatment crosses lithological and selected geological event informations (e.g different metamorphic and alteration events).</p><p>Subsequent geological field investigations with associated sampling and laboratory analyses (combining optical microscopy, microprobe and SEM analyses) allowed us to identify and characterize fibrous and asbestiform mineralogical species. Results of this work particularly emphasize: (i) the importance of actinolite-asbestos in doleritic rocks, and (ii) the occurrence of fibrous actinolite/tremolite in different marbles and skarns. Finally, we present a 1: 50,000 scale map of potential NOA occurrences in the Pyrenees.</p><p>Conversely, field observations allowed us to improve both the lithostratigraphic and the event geological maps, in particular with the identification of geological domains where intense hydrothermal alteration was not previously mapped. All the data (maps of potential NOA occurrences, field observations and results of laboratory analyses) are stored in a geospatial database, partly accessible to the public. This work illustrates a possible use of geological event maps as a powerful innovative and predictivity tool. This approach will be useful in the context of the evolution of French regulations now imposing the search for asbestos before all types of works in natural environments.</p>

Geological setting of the Tverrfjell copper/zinc deposit, Central Norway

1985 ◽  
Vol 74 (3) ◽  
pp. 467-482 ◽  
Author(s):  
Ralf Krupp ◽  
Gabriele Krupp
Keyword(s):  
Zinc Deposit ◽  
Geological Setting ◽  
Copper Zinc

Evolution of the south-central segment of the Archean Abitibi Belt, Quebec. Part III: Plutonic and metamorphic evolution and geotectonic model

1983 ◽  
Vol 20 (9) ◽  
pp. 1374-1388 ◽  
Author(s):  
Erich Dimroth ◽  
Laszlo Imreh ◽  
Normand Goulet ◽  
Michel Rocheleau
Keyword(s):  
Hydrothermal Alteration ◽  
High Intensity ◽  
Thermal Contact ◽  
Volcanic Rocks ◽  
Metamorphic Grade ◽  
Contact Metamorphism ◽  
Metamorphic Evolution ◽  
South Central ◽  
Central Segment ◽  
Basin System

Textural criteria permit distinction between the pre-Kenoran and Kenoran phases of plutonism and metamorphism. The pre-Kenoran plutons and pre-Kenoran metamorphic phases are directly related to the volcanic evolution. Synvolcanic tonalite–trondhjemite plutons and swarms of mafic and felsic dykes core central volcanic complexes. The volcanic rocks underwent three types of pre-Kenoran metamorphism, namely, a pervasive alteration, a thermal contact metamorphism that affected narrow aureoles around synvolcanic plutons, and a high-intensity hydrothermal alteration that affected cross-cutting pipes in central volcanic complexes.Synkinematic Kenoran metamorphism resulted in the growth of minerals (chlorite, actinolite, etc.) parallel to schistosities. Synkinematic metamorphic grade ranges form the pumpellyite–prehnite facies to the amphibolite facies. Late- to post-kinematic metamorphic phases resulted in the growth of minerals across schistosities. Syn- to post-kinematic plutons are not voluminous in the part of the Abitibi Belt described here, but they underlie vast areas in the Bellecombe Belt. They range from gneissose early synkinematic plutons to late-kinematic plutons that have well preserved igneous textures.The paleogeographic, tectonic, plutonic, and metamorphic histories of the Abitibi and Bellecombe belts are reviewed and we conclude that the belts are analogous to an island arc – fore-arc basin system.

Axial primary halo characterization and deep orebody prediction in the Ashele copper-zinc deposit, Xinjiang, NW China

2020 ◽  
Vol 213 ◽  
pp. 106509
Author(s):  
Chaojie Zheng ◽  
Xianrong Luo ◽  
Meilan Wen ◽  
Pooria Ebrahimi ◽  
Panfeng Liu ◽  
...  
Keyword(s):  
Zinc Deposit ◽  
Nw China ◽  
Copper Zinc

Application of LA-ICP-MS to process mineralogy: Gallium and germanium recovery at Kipushi copper-zinc deposit

2022 ◽  
Vol 176 ◽  
pp. 107322
Author(s):  
M. Kelvin ◽  
E. Whiteman ◽  
J. Petrus ◽  
M. Leybourne ◽  
V. Nkuna
Keyword(s):  
Zinc Deposit ◽  
Icp Ms ◽  
Copper Zinc ◽  
Process Mineralogy

Metasomatism in the Whin Sill of the North of England. Part II: Hydrothermal Alteration by Juvenile Solutions

1929 ◽  
Vol 66 (5) ◽  
pp. 221-238 ◽  
Author(s):  
L. R. Wager
Keyword(s):  
Thin Layer ◽  
Hydrothermal Alteration ◽  
Outer Surface ◽  
Large Scale ◽  
General Character ◽  
Small Scale ◽  
Hydrothermal Solutions ◽  
Vein Quartz ◽  
Columnar Jointing ◽  
The North

In Teesdale and Weardale, at all exposures that have been examined, the Whin Sill is cut by a system of approximately vertical, sweeping, joint planes. These are distinct in general character from, and are on a larger scale than, the columnar jointing which is conspicuous in all vertical scars of Whin Sill. The pattern of the larger scale jointing on a horizontal surface varies with the depth within the sill; Fig. 1 shows diagrammatically the appearance at a depth of about 10 feet below the top of the sill; the inset Fig. 2, of the upper surface of the sill, shows how the joints have a more irregular course in the more rapidly cooled part of the dolerite. The joints do not usually pass from the dolerite into the adjacent sediment and Fig. 2 also shows a thin layer of baked sediment, attached to the outer surface of the sill, which the joint does not penetrate. The large scale jointing is often displaced by the small scale columnar jointing in a way that proves the large scale jointing to be the earlier. For the purposes of this paper, the early, large scale, joints will be referred to simply as the early joints. The walls of the early joints, for a distance of an inch or so, have been altered by hydrothermal solutions, to a rock which, although varying in composition with the distance from the joint, consists essentially of chlorite, quartz, and carbonate. The joint walls are usually about a quarter of an inch apart, and the space between them is filled with calcite and quartz. The calcite is present in greater abundance than the quartz which occurs in well shaped crystals of vein-quartz habit.

Hydrothermal alteration, veining, and fluid-inclusion characteristics of the Kalzas wolframite deposit, Yukon

1989 ◽  
Vol 26 (10) ◽  
pp. 2106-2115 ◽  
Author(s):  
J. V. Gregory Lynch
Keyword(s):  
Hydrothermal Alteration ◽  
Sedimentary Rocks ◽  
Hydrothermal Activity ◽  
Contact Metamorphism ◽  
Quartz Veins ◽  
The Core ◽  
Outer Periphery ◽  
Windermere Supergroup ◽  
Homogenization Temperatures ◽  
Host Rocks

Kalzas is a sheeted vein and stockwork wolframite deposit, crosscutting continental margin sedimentary rocks of the Proterozoic Windermere Supergroup in central Yukon. Mineralization is synchronous with Cretaceous post-tectonic granites of the Selwyn Plutonic Suite.Parallel sets of planar quartz veins contain coarse euhedral wolframite and are generally oriented perpendicular to southeast-plunging fold axes. Widespread alteration of the host rocks and intense stockwork veining surround the veins. Alteration and mineralization show a distinct concentric zonation across a 2.5 km long southeast-trending oval. The core zone is characterized by orthoclase contained within quartz–tourmaline–wolframite veins. Minor phases include apatite, molybdenite, bismuthinite, pyrite, chalcopyrite, and pyrrhotite. Host rocks are prevasively tourmalinized and sericitized. Hydrothermal alteration here at the core of the system overprints early biotitization of the host rocks. The biotitization appears to have been the result of earlier contact metamorphism from a hidden pluton situated beneath the deposit that converted the chloritic groundmass of the metasediments to biotite. At the fringe of wolframite mineralization, cassiterite occurs with quartz, muscovite, and tourmaline, whereas orthoclase is distinctly lacking. The outer periphery of the concentrically zoned sequence features pervasive sericitization, disseminated pyrite, and the disappearance of tourmaline. Here, quartz veins are barren except for minor galena.Three main stages mark the mineralogical evolution of the deposit: (1) early biotitization of the chloritic host rocks in the core area; (2) quartz-dominated veining with internally complex timing relations, hydrothermal alteration, and zoning; and (3) carbonate veining and replacement of wolframite by scheelite.Fluid inclusions within quartz are dominated by H2O and contain variable amounts of CO2 as well as minor CH4 and NaCl. The CO2 content ranges from approximately 0 to 6 mol%. The fluids are generally dilute but locally contain as much as 7 wt.% NaCl equivalent. Homogenization temperatures are variable: for quartz, 160–340 °C; for cassiterite, 280–350 °C; and for apatite, 220–360 °C. Minimum hydrothermal pressures at the time of mineralization are estimated to have been in the range 300–600 bar (1 bar = 100 kPa). Fluctuations in pressure with cooling appear to have resulted in CO2 immiscibility and the formation of late-stage carbonates at the termination of hydrothermal activity.

The discovery of a copper-zinc deposit at Garon Lake, Quebec

1960 ◽  
Vol 55 (2) ◽  
pp. 338-353 ◽  
Author(s):  
G. F. Joklik
Keyword(s):  
Zinc Deposit ◽  
Copper Zinc
Sign in / Sign up

Export Citation Format

Share Document