THE LITHOGEOCHEMICAL SIGNATURES OF HYDROTHERMAL ALTERATION FRAMING PALEOPROTEROZOIC AURIFEROUS QUARTZ VEINS, FISHER PROPERTY, SEABEE GOLD OPERATION, SASKATCHEWAN, CANADA

2020 ◽  
Author(s):  
Courtney Onstad ◽  
◽  
Kevin M. Ansdell ◽  
Camille Partin ◽  
Anders Carlson
Keyword(s):  
Hydrothermal Alteration ◽  
Quartz Veins

scholarly journals HYDROTHERMAL ALTERATION AND VEIN TYPES OF THE RANDU KUNING PORPHYRY Cu-Au DEPOSIT AT SELOGIRI AREA, WONOGIRI

2014 ◽  
Vol 9 (1) ◽  
pp. 48-61
Author(s):  
Sutarto Sutarto ◽  
Arifudin Idrus ◽  
Sapto Putranto ◽  
Agung Harjoko ◽  
Lucas D Setijadji ◽  
...  
Keyword(s):  
Hydrothermal Alteration ◽  
Fault Zones ◽  
Alteration Zone ◽  
Quartz Veins ◽  
Porphyry Cu ◽  
Centre Line ◽  
Argillic Alteration ◽  
Intrusive Rocks ◽  
Hydrothermal Alteration Zones ◽  
Alteration Pattern

Many Tertiary hydrothermal altered dioritic composition intrusive rocks were found at the Randu Kuning area and its vicinity, Selogiri, including hornblende microdiorite, hornblende-pyroxene diorite and quartz diorite. The hydrothermal fluids which responsible for the alteration and mineralization at the area is associated with the occurence of the horblende microdiorite intrusion. The alteration zone at the Randu Kuning area and its vicinity can be divided intoseveral hydrothermal alteration zones, such as potassic (magnetite-biotite-K feldspar), prophyllitic (chlorite-magnetite-epidote-carbonate), phyllic (quartz-sericite-chlorite) and argillic (clay mineral-sericite). The alteration pattern in the Randu Kuning porphyry Cu-Au deposit is tipically a diorite model characterising by the domination of potassic alteration and prophyllitic zone. Phyllic and argillic alteration types are restrictive found within the fault zones. A lot of porphyry vein types were found and observed at the Randu Kuning area, and classified into at least seven vein types. The paragenetic sequence of those veins from theearliest to the latest respectively are 1). Magnetite-chalcopyrite±quartz-biotite veinlets, 2). Quartz±magnetite (A type) veins, 3). Banded/Laminated quartz-magnetite (M type) veins, 4). Quartz±K feldspar (B type)veins, 5). Quartz with thin centre line sulphide (AB type) veins, 6). Pyrite±chalcopyrite (C type) veinlets, and 7). Pyrite-quartz+chalcopyrire+carbonate (D type) veins. Gold and copper mineralisation of the Randu Kuning Porphyry Cu-Au deposit, mostly related to the presence of quartz veins/veinlets containing sulfide i.e. Quartz with thin centre line sulphide veins, Pyrite±chalcopyrite veinlets, and Pyrite-quartz+chalcopyrire+carbonate veins.

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.

Relationship of hydrothermal alteration to structure and stratigraphy at the Coniaurum gold mine, northern Ontario

1988 ◽  
Vol 25 (12) ◽  
pp. 2028-2040
Author(s):  
Darwin W. Piroshco ◽  
C. Jay Hodgson
Keyword(s):  
Hydrothermal Alteration ◽  
Volcanic Rocks ◽  
Shear Zones ◽  
Wall Rock ◽  
Gold Mine ◽  
Northern Ontario ◽  
Quartz Veins ◽  
Mineral Assemblages ◽  
Relationship Of ◽  
Ore Zones

The gold mineralized zones of the Coniaurum mine, Porcupine camp, northeastern Ontario, are on the eastern end of the northeast-trending Hollinger–Mclntyre ore system. The ore zones are quartz–ankerite (plus accessories) veins and vein systems and associated pyritic wall rock, hosted by a sequence of mafic volcanic rocks and discordant quartz–feldspar porphyry stocks of Archean age.A least altered facies and three alteration facies can be distinguished within the mafic volcanic rocks: a chlorite facies, an ankerite facies, and a vein envelope facies. The chlorite facies is widespread, overprints the least altered facies (i.e., chlorite replaces actinolite), and hosts barren and locally mineralized quartz veins bordered by vein envelope facies alteration. The ankerite facies is coextensive with subparallel shear zones, which crosscut me axial trace of the Coniaurum anticline, and hosts most of the mineralized vein systems. Addition mineralization occurs within graphitic sediments in the crest area of the Coniaurum anticline.On the basis of the above relationships, the shear zones, hydrothermal alteration, and mineralization are interpreted to be late (i.e., syn- to post-development of the Coniaurum anticline).The mineral assemblages of the chlorite and ankerite alteration facies are interpreted as resulting from lateral gradients in [Formula: see text]. Replacement textures between minerals at the alteration facies boundaries indicate the hydrothermal system first grew outwards but later collapsed inwards and the vein envelope facies is superimposed on the more widespread ankerite and chlorite facies.

scholarly journals Orogenic Gold in Transpression and Transtension Zones: Field and Remote Sensing Studies of the Barramiya–Mueilha Sector, Egypt

2019 ◽  
Vol 11 (18) ◽  
pp. 2122 ◽  
Author(s):  
Basem Zoheir ◽  
Mohamed Abd El-Wahed ◽  
Amin Beiranvand Pour ◽  
Amr Abdelnasser
Keyword(s):  
Remote Sensing ◽  
Hydrothermal Alteration ◽  
Gold Mineralization ◽  
Shear Zones ◽  
Island Arc ◽  
Quartz Veins ◽  
Vein Formation ◽  
Time Space ◽  
Band Ratioing ◽  
Sentinel 2

Multi-sensor satellite imagery data promote fast, cost-efficient regional geological mapping that constantly forms a criterion for successful gold exploration programs in harsh and inaccessible regions. The Barramiya–Mueilha sector in the Central Eastern Desert of Egypt contains several occurrences of shear/fault-associated gold-bearing quartz veins with consistently simple mineralogy and narrow hydrothermal alteration haloes. Gold-quartz veins and zones of carbonate alteration and listvenitization are widespread along the ENE–WSW Barramiya–Um Salatit and Dungash–Mueilha shear belts. These belts are characterized by heterogeneous shear fabrics and asymmetrical or overturned folds. Sentinel-1, Phased Array type L-band Synthetic Aperture Radar (PALSAR), Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER), and Sentinel-2 are used herein to explicate the regional structural control of gold mineralization in the Barramiya–Mueilha sector. Feature-oriented Principal Components Selection (FPCS) applied to polarized backscatter ratio images of Sentinel-1 and PALSAR datasets show appreciable capability in tracing along the strike of regional structures and identification of potential dilation loci. The principal component analysis (PCA), band combination and band ratioing techniques are applied to the multispectral ASTER and Sentinel-2 datasets for lithological and hydrothermal alteration mapping. Ophiolites, island arc rocks, and Fe-oxides/hydroxides (ferrugination) and carbonate alteration zones are discriminated by using the PCA technique. Results of the band ratioing technique showed gossan, carbonate, and hydroxyl mineral assemblages in ductile shear zones, whereas irregular ferrugination zones are locally identified in the brittle shear zones. Gold occurrences are confined to major zones of fold superimposition and transpression along flexural planes in the foliated ophiolite-island arc belts. In the granitoid-gabbroid terranes, gold-quartz veins are rather controlled by fault and brittle shear zones. The uneven distribution of gold occurrences coupled with the variable recrystallization of the auriferous quartz veins suggests multistage gold mineralization in the area. Analysis of the host structures assessed by the remote sensing results denotes vein formation spanning the time–space from early transpression to late orogen collapse during the protracted tectonic evolution of the belt.

Hydrothermal Alteration in the Carrock Fell Area, Cumberland, England

1962 ◽  
Vol 99 (1) ◽  
pp. 1-8 ◽  
Author(s):  
A. Ewart
Keyword(s):  
Hydrothermal Alteration ◽  
Quartz Veins ◽  
Thermal Metamorphism ◽  
The North ◽  
Rock Types ◽  
Southern Margin

AbstractWithin this area are developed a series of quartz veins which cut three rock types, the Grainsgill granite, part of the southern margin of the Carrock Fell gabbro to the north, and an intervening area of hornfels belonging to the Skiddaw Slate Series. Both the hornfels and the gabbro have suffered thermal metamorphism due to the granite, and in addition, the hornfels has undergone a very localized metamorphism due to the gabbro. All three rock types have undergone a further hydrothermal alteration due to the quartz veins. The microscopic changes involved in this alteration are described and it is shown that the end product in each case is essentially similar to a greisen, with the addition of pyrite and arsenopyrite.

Geology of unmineralized and gold-bearing iron formation, Contwoyto Lake – Point Lake region, Northwest Territories, Canada

1989 ◽  
Vol 26 (1) ◽  
pp. 46-64 ◽  
Author(s):  
Paul G. Lhotka ◽  
Bruce E. Nesbitt
Keyword(s):  
Hydrothermal Alteration ◽  
Thermal Conditions ◽  
Iron Formation ◽  
Small Scale ◽  
Iron Sulphide ◽  
Quartz Veins ◽  
Slave Province ◽  
Lake Region ◽  
Iron Sulphides ◽  
Gold Bearing

Numerous gold occurrences, including the Lupin mine, exist in Archean iron formation within the Contwoyto Lake – Point Lake region of the Slave Province. Early studies suggested that gold was a syngenetic component of the iron formation; however, the present study suggests that the gold and sulphides are epigenetic.At both the Lupin mine and small-scale gold occurrences gold is associated with quartz veins and concentrations of pyrrhotite or pyrite and of arsenides (arsenopyrite ± loellingite) in iron formation. The quartz veins contain 0.03–1.00 ppm Au and comprise sulphide-poor quartz. A zoned sequence of hydrothermal alteration is present in iron formation adjacent to quartz veins. Immediately adjacent to the veins a calc-silicate lithology (0.03–1.00 ppm Au) is sometimes developed that comprises hedenbergite + quartz ± epidote ± scheelite ± grossular. Next is an arsenide-rich zone (5–30 ppm Au) comprising hornblende + quartz ± hedenbergite ± epidote ± actinolite. The next zone is an iron-sulphide zone (5–30 ppm Au), lacking abundant arsenides but containing pyrrhotite or pyrite and hornblende + quartz ± hedenbergite ± epidote ± actinolite. Farther from the veins, iron formation is unmineralized (≤0.03 ppm Au), lacks sulphides, and comprises grunerite + quartz ± magnetite. In the transition zone, hornblende replaces grunerite, and iron sulphides replace amphiboles and magnetite. The scale of the sequence of zones varies from millimetres to metres about individual veins. In well-mineralized portions of the Lupin mine, where quartz veins are closely spaced, unmineralized iron formation is absent between the veins.The symmetrical zonal pattern in the mineralogy and gold values about the veins at Lupin and at the small-scale occurrences indicates that mineralization at both scales of gold occurrence formed by an epigenetic process. Mineralization occurred by selective sulphidation of iron formation after most of the Archean deformation and was coincident, or nearly coincident, with peak thermal conditions. Gold was probably transported as an aqueous gold–sulphide complex and deposited as a result of sulphidation reactions.

Gold mineralisation at Eqi, north-east Disko Bugt, West Greenland

1999 ◽  
pp. 129-140 ◽  
Author(s):  
Henrik Stendal ◽  
Christian Knudsen ◽  
Mogens Marker ◽  
Bjørn Thomassen
Keyword(s):  
Hydrothermal Alteration ◽  
Hydrothermal Activity ◽  
Gold Deposits ◽  
Volcanic Complex ◽  
Igneous Complex ◽  
Original Series ◽  
West Greenland ◽  
Quartz Veins ◽  
North East ◽  
Altered Zone

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Stendal, H., Knudsen, C., Marker, M., & Thomassen, B. (1999). Gold mineralisation at Eqi, north-east Disko Bugt, West Greenland. Geology of Greenland Survey Bulletin, 181, 129-140. https://doi.org/10.34194/ggub.v181.5121 _______________ Gold mineralisation at Eqi, north-east Disko Bugt, West Greenland, is hosted in Archaean (c. 2800 Ma old) supracrustal rocks; the latter are divided by a thrust into a lower volcanic unit and an upper sedimentary and volcaniclastic unit. The lower volcanic unit comprises three parts: a basal pillowed greenstone sequence, an acid volcanic complex, and an upper mafic igneous complex. Intensive hydrothermal activity resulted in extensive carbonatisation and sericitisation, which is most intense just above a system of acid feeder dykes within the basal greenstone sequence. Primary enrichment in gold took place during pervasive hydrothermal alteration, and the gold is mainly located in carbonate-altered rocks. Remobilisation of gold occurred during formation of later quartz veins in the altered zone; these quartz veins have gold contents of up to 60 ppm. The geological setting, geochemistry and formation of the gold mineralisation at Eqi is similar to many Archaean gold deposits in the Abitibi belt of Canada.

Sign in / Sign up

Export Citation Format

Share Document