ORCID Profile
0000-0003-3254-702X
Current Organisation
Norwegian University of Life Sciences
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Publisher: Elsevier BV
Date: 2012
Publisher: Academy of Science of South Africa
Date: 21-06-2016
DOI: 10.4314/WSA.V42I2.05
Publisher: Public Library of Science (PLoS)
Date: 08-04-2014
Publisher: Mineralogical Society of America
Date: 03-07-2023
DOI: 10.2138/AM-2022-8440
Abstract: We evaluate the controlling factors of hydrothermal wolframite and scheelite precipitation in the quartz vein-type Jiaoxi tungsten deposit situated in the western part of the Lhasa terrane (Tibet, China) using texture, major and trace element mineral geochemistry, and sulfur stable isotope geochemistry. Pyrite and chalcopyrite that are intergrown with Fe-enriched wolframite and siderite, have distinct in situ S isotope compositions (δ34SV-CDT) of −31.38 to +1.77‰, and +2.07 to +2.30‰, respectively. Major and trace element contents and in situ S isotope compositions of pyrite and chalcopyrite indicate that the hydrothermal evolution involved fluid-fluid mixing and greisenization. We report evidence for an early magmatic fluid, which is characterized by the enrichment of W, Mn, Zr, Ti, Sc, and Sn and depletion of Fe. This magmatic fluid was diluted by meteoric water and interacted with biotite monzogranite porphyry to leach Fe, Mg, and Zn into the system to form wolframites with variable Fe/(Fe+Mn) ratios ranging between 0.06–0.84. The late Fe-enriched magmatic fluid released from the muscovite granite mixed with meteoric water that leached minor Fe and S from shale to form late shale-hosted wolframite with a Fe/(Fe+Mn) mass ratio of & .75 and coeval siderite and sulfides. This study highlights that multiple Fe sources were present in the system, including muscovite granite-released Fe through fluid exsolution, biotite monzogranite porphyry-released Fe during greisenization, and minor Fe released from the shale as a result of meteoric water leaching.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Schweizerbart
Date: 29-11-1999
Publisher: Springer Science and Business Media LLC
Date: 18-09-2010
Publisher: Elsevier BV
Date: 11-2012
Publisher: Springer Science and Business Media LLC
Date: 05-11-2005
Publisher: Elsevier BV
Date: 10-2018
Publisher: Geological Society of America
Date: 03-2009
DOI: 10.1130/G25284A.1
Publisher: Elsevier BV
Date: 03-2019
Publisher: Society of Economic Geologists
Date: 03-2021
DOI: 10.5382/ECONGEO.4791
Abstract: The Watershed tungsten deposit (49.2 Mt avg 0.14% WO3) lies within the Mossman orogen, which comprises deformed Silurian-Ordovician metasedimentary rocks of the Hodgkinson Formation intruded by Carboniferous-Permian granites of the Kennedy Igneous Association. The Hodgkinson Formation in the Watershed area comprises skarn-altered conglomerate, psammite, and slate units that record four deformation events evolving from ductile, isoclinal, colinear folding with transposition (D1–D3) to brittle ductile shear zones (D4). Multiple felsic to intermediate dikes cut across the metasedimentary rocks at Watershed including the following: (1) Carboniferous, monzonite dikes (zircon U/Pb age of 350 ± 7 Ma) emplaced during D1–2 and (2) Permian granite plutons and dikes (zircon U/Pb ages of 291 ± 6, 277 ± 6, and 274 ± 6 Ma) and diorite (zircon U/Pb age of 281 ± 5 Ma) emplaced during D4. Tungsten mineralization is largely restricted to skarn-altered conglomerate, which preserves a peak metamorphic mineralogy formed during ductile deformation and comprises garnet (Grt40–87 Alm0–35Sps1–25Adr0–16), actinolite, quartz, clinopyroxene (Di36–59Hd39–61Jhn1–5), and titanite. A first mineralization event corresponds to the crystallization of disseminated scheelite in monzonite dikes (pre-D3) and adjacent units, with scheelite grains aligned in the S1–2 fabric and affected by D3 folding. This event enriched the Hodgkinson Formation in tungsten. The bulk of the scheelite mineralization formed during a second event and is concentrated in multistaged, shear-related, quartz-oligoclase-bearing veins and vein halos (muscovite 40Ar-39Ar weighted average age of 276 ± 6 Ma), which were emplaced during D4. The multistage veins developed preferentially in competent, skarn-altered conglomerate units and formed synchronous with four retrograde alteration stages. The retrograde skarn minerals include clinozoisite after garnet, quartz, plagioclase, scheelite, and phlogopite with minor sodium-rich hibole, which formed during retrograde stages 1 and 2, accompanied by later muscovite, calcite, and chlorite formed during retrograde stage 3. Retrograde stage 4 was a late-tectonic, noneconomic sulfide stage. The principal controls on scheelite mineralization at Watershed were the following: (1) early monzonite dikes enriched in scheelite (2) D4 shear zones that acted as fluid conduits transporting tungsten from source areas to traps (3) skarn-altered conglomerate lenses that provide a competent host to facilitate vein formation and a source for calcium to form scheelite and (4) an extensional depositional environment characterized by vein formation and normal faulting, which provide trapping structures for tungsten-bearing fluids, with decompression being a likely control on scheelite deposition. The coexistence of scheelite with oligoclase in monzonite dikes and veins suggests that tungsten was transported as NaHWO40. Exploration in the area should target Carboniferous monzonite, associated with later syn-D4 shear zones cutting skarn-altered conglomerate.
Publisher: Elsevier BV
Date: 04-2022
Publisher: Elsevier BV
Date: 09-2022
Publisher: Elsevier BV
Date: 02-1999
Publisher: Elsevier BV
Date: 12-2017
Publisher: Oxford University Press (OUP)
Date: 05-08-2021
DOI: 10.1093/PETROLOGY/EGAB066
Abstract: Many intrusions with adakite-like affinities in collisional zones have obviously higher K2O contents and K2O/Na2O ratios compared with counterparts in subduction zones. A suite of Eocene post-collisional high-K2O adakite-like intrusions, mafic microgranular enclaves, and potassic–ultrapotassic l rophyres in the Machangqing complex are associated with the Indian–Asian collision within the western Yangtze Craton, southeastern Tibet. The potassic–ultrapotassic l rophyres, with a zircon U–Pb age of 34·1 ± 0·2 Ma, have high K2O and MgO contents, are enriched in light rare earth elements and large ion lithophile elements, and display high Rb/Sr, and low Ba/Rb and Nb/U ratios. They show enriched isotopic compositions [i.e. (87Sr/86Sr)i = 0·7070–0·7082, εNd(t) = −3·2 to −2·8], and zircon εHf(t) values (−1·6 to +2·6). Their parental magmas are inferred to have been derived from partial melting of an enriched lithospheric mantle, metasomatized by subduction-related fluids. The adakite-like intrusions, with zircon U–Pb ages of 35·4 ± 0·4 and 35·2 ± 0·3 Ma, are characterized by high SiO2 (68·8–71·1 wt%) and Al2O3 (14·0–15·3 wt%) contents, high Sr/Y (41–118) ratios, and low Y (5·3–14·7 ppm) contents. They show low contents of compatible elements (e.g. Ni = 9·5–36·2 ppm) and total REE, and lower Mg# values than the l rophyres and mafic microgranular enclaves. The adakite-like intrusions have positive large ion lithophile element anomalies, especially potassium, negative high field strength element anomalies, negative εNd(t) (−5·5 to −3·3), and high (87Sr/86Sr)i (0·7064–0·7070) and zircon εHf(t) values (0·0 to +2·7), indicating that they were formed by partial melting of the juvenile lower crust. Mafic microgranular enclaves hosted in the adakite-like intrusions, with U–Pb ages similar to the l rophyre of c. 34 Ma, exhibit disequilibrium textures, and some of them contain phlogopite. They exhibit potassic–ultrapotassic affinity, and relatively high compatible element contents. They are also characterized by enriched isotopic compositions with (87Sr/86Sr)i = 0·7063–0·7074, εNd(t) = −6·6 to −4·1, and variable zircon εHf(t) values (−0·6 to +3·2). Petrological and geochemical evidence suggests that the mafic microgranular enclaves were formed by magma mixing between potassic–ultrapotassic and pristine adakite-like melts. We propose a magma mixing model for the origin of the high-K2O adakite-like intrusions from the Machangqing complex. In this model, the formation of high-K2O adakite-like intrusions occurred in three stages: (1) partial melting of metasomatized lithospheric mantle generated potassic–ultrapotassic mafic melts (2) underplating of these mafic melts beneath thickened juvenile lower crust resulted in partial melting of juvenile mafic lower crust and the generation of adakite-like melts (3) magma mixing involved 80 % pristine adakite-like melts and 20 % potassic–ultrapotassic melts. This leads to the enrichment of K2O in these adakite-like intrusions, and magma differentiation further promotes K2O enrichment. These results are applicable to compositionally similar adakite-like rocks produced in other collisional zones, such as the Tibet, Sulu–Dabie and Zagros orogenic belts. From which we conclude that in continental collision zones, the post-collisional mantle-derived magmas characterized by potassic–ultrapotassic affinities are spatially associated with coeval collision-related adakite-like intrusions that originated from lower crustal melting. The emplacement of adakite-like and potassic–ultrapotassic rocks is controlled by the same fault systems, which increases the possibility of interaction between these two magma suites.
Publisher: Elsevier BV
Date: 10-2021
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 02-1999
Publisher: Springer Science and Business Media LLC
Date: 08-2001
Publisher: Elsevier BV
Date: 10-2014
Publisher: Society of Economic Geologists
Date: 2020
DOI: 10.5382/SP.23.08
Abstract: The Geita mine is operated by AngloGold Ashanti and currently comprises four gold deposits mined as open pits and underground operations in the Geita greenstone belt, Tanzania. The mine produces ~0.5 Moz of gold a year and has produced ~8.3 Moz since 2000, with current resources estimated at ~6.5 Moz, using a lower cut-off of 0.5 g/t. The geologic history of the Geita greenstone belt involved three tectonic stages: (I) early (2820–2700 Ma) extension (D1) and formation of the greenstone sequence in an oceanic plateau environment (II) shortening of the greenstone sequence (2700–2660 Ma) involving ductile folding (D2–5) and brittle-ductile shearing (D6), coincident with long-lived igneous activity concentrated in five intrusive centers and (III) renewed extension (2660–2620 Ma) involving strike-slip and normal faulting (D7–8), basin formation, and potassic magmatism. Major gold deposits in the Geita greenstone belt formed late in the history of the greenstone belt, during D8 normal faulting at ~2640 Ma, and the structural framework, mineral paragenesis, and timing of gold precipitation is essentially the same in all major deposits. Gold is hosted in iron-rich lithologies along contacts between folded metaironstone beds and tonalite-trondhjemite-granodiorite (TTG) intrusions, particularly where the contacts were sheared and fractured during D6–7 faulting. The faults, together with damage zones created along D3 fold hinges and D2–3 hydrothermal breccia zones near intrusions, formed microfracture networks that were reactivated during D8. The fracture networks served as conduits for gold-bearing fluids i.e., lithologies and structures that trap gold formed early, but gold was introduced late. Fluids carried gold as Au bisulfide complexes and interacted with Fe-rich wall rocks to precipitate gold. Fluid-rock interaction and mineralization were enhanced as a result of D8 extension, and localized hydrofracturing formed high-grade breccia ores. Gold is contained in electrum and gold-bearing tellurides that occur in the matrix and as inclusions in pyrrhotite and pyrite. The gold mineralization is spatially linked to long-lived, near-stationary intrusive centers. Critical factors in forming the deposits include the (syn-D2–6) formation of damage zones in lithologies that enhance gold precipitation (Fe-rich lithologies) late tectonic reactivation of the damage zones during extensional (D8) faulting with the introduction of an S-rich, gold-bearing fluid and efficient fluid-rock interaction in zones that were structurally well prepared.
Publisher: Geological Society of South Africa
Date: 09-2005
DOI: 10.2113/108.3.439
Publisher: Elsevier BV
Date: 07-2005
Publisher: Elsevier BV
Date: 04-2021
Publisher: Society of Economic Geologists
Date: 2020
DOI: 10.5382/ECONGEO.4696
Abstract: The Mt. Carlton Au-Ag-Cu deposit, northern Bowen basin, northeastern Australia, is an uncommon ex le of a sublacustrine hydrothermal system containing economic high-sulfidation epithermal mineralization. The deposit formed in the early Permian and comprises vein- and hydrothermal breccia-hosted Au-Cu mineralization within a massive rhyodacite porphyry (V2 open pit) and stratabound Ag-barite mineralization within volcano-lacustrine sedimentary rocks (A39 open pit). These orebodies are all associated with extensive advanced argillic alteration of the volcanic host rocks. Stable isotope data for disseminated alunite (δ34S = 6.3–29.2‰ δ18OSO4 = –0.1 to 9.8‰ δ18OOH = –15.3 to –3.4‰ δD = –102 to –79‰) and pyrite (δ34S = –8.8 to –2.7‰), and void-filling anhydrite (δ34S = 17.2–19.2‰ δ18OSO4 = 1.8–5.7‰), suggest that early advanced argillic alteration formed within a magmatic-hydrothermal system. The ascending magmatic vapor (δ34SΣS ≈ –1.3‰) was absorbed by meteoric water (~50–60% meteoric component), producing an acidic (pH ≈ 1) condensate that formed a silicic → quartz-alunite → quartz-dickite-kaolinite zoned alteration halo with increasing distance from feeder structures. The oxygen and hydrogen isotope compositions of alunite-forming fluids at Mt. Carlton are lighter than those documented at similar deposits elsewhere, probably due to the high paleolatitude (~S60°) of northeastern Australia in the early Permian. Veins of coarse-grained, banded plumose alunite (δ34S = 0.4– 7.0‰ δ18OSO4 = 2.3–6.0‰ δ18OOH = –10.3 to –2.9‰ δD = –106 to –93‰) formed within feeder structures during the final stages of advanced argillic alteration. Epithermal mineralization was deposited subsequently, initially as fracture- and fissure-filling, Au-Cu–rich assemblages within feeder structures at depth. As the mineralizing fluids discharged into lakes, they produced syngenetic Ag-barite ore. Isotope data for ore-related sulfides and sulfosalts (δ34S = –15.0 to –3.0‰) and barite (δ34S = 22.3–23.8‰ δ18OSO4 = –0.2 to 1.3‰), and microthermometric data for primary fluid inclusions in barite (Th = 116°– 233°C 0.0–1.7 wt % NaCl), are consistent with metal deposition at temperatures of ~200 ± 40°C (for Au-Cu mineralization in V2 pit) and ~150 ± 30°C (Ag mineralization in A39 pit) from a low-salinity, sulfur- and metal-rich magmatic-hydrothermal liquid that mixed with vapor-heated meteoric water. The mineralizing fluids initially had a high-sulfidation state, producing enargite-dominated ore with associated silicification of the early-altered wall rock. With time, the fluids evolved to an intermediate-sulfidation state, depositing sphalerite- and tennantite-dominated ore mineral assemblages. Void-filling massive dickite (δ18O = –1.1 to 2.1‰ δD = –121 to –103‰) with pyrite was deposited from an increasingly diluted magmatic-hydrothermal liquid (≥70% meteoric component) exsolved from a progressively degassed magma. Gypsum (δ34S = 11.4–19.2‰ δ18OSO4 = 0.5–3.4‰) occurs in veins within postmineralization faults and fracture networks, likely derived from early anhydrite that was dissolved by circulating meteoric water during extensional deformation. This process may explain the apparent scarcity of hypogene anhydrite in lithocaps elsewhere. While the Mt. Carlton system is similar to those that form subaerial high-sulfidation epithermal deposits, it also shares several key characteristics with magmatic-hydrothermal systems that form base and precious metal mineralization in shallow-submarine volcanic arc and back-arc settings. The lacustrine paleosurface features documented at Mt. Carlton may be useful as exploration indicators for concealed epithermal mineralization in similar extensional terranes elsewhere.
Publisher: Oxford University Press (OUP)
Date: 07-2004
Publisher: The Geological Society of Finland
Date: 12-1989
Publisher: Gemological Institute of America
Date: 06-1998
Publisher: Elsevier BV
Date: 02-2020
Publisher: Springer Science and Business Media LLC
Date: 22-09-2014
Publisher: Springer Science and Business Media LLC
Date: 04-2023
DOI: 10.1007/S00410-023-02003-1
Abstract: The Paleoproterozoic Bakhuis Granulite Belt (BGB) in Surinam, South America, shows ultrahigh-temperature metamorphism (UHTM) at temperatures of around 1000 °C which, unusually, produced peak-to-near-peak cordierite with sillimanite and, in some cases, Al-rich orthopyroxene on a regional scale. Mg-rich cordierite (Mg/(Mg + Fe) = 0.88) in a sillimanite-bearing metapelitic granulite has a maximum birefringence of second-order blue (ca. 0.020) indicative of a considerable amount of CO 2 ( 2 wt%) within its structural channels. SIMS microanalysis confirms the presence of 2.57 ± 0.19 wt% CO 2 , the highest CO 2 concentration found in natural cordierite. This high CO 2 content has enabled the stability of cordierite to extend into UHT conditions at high pressures and very low to negligible H 2 O activity. Based on a modified calibration of the H 2 O–CO 2 incorporation model of Harley et al. (J Metamorph Geol 20:71–86, 2002), this cordierite occupies a stability field that extends from 8.8 ± 0.6 kbar at 750 °C to 11.3 ± 0.65 kbar at 1050 °C. Volatile-saturated cordierite with 2.57 wt% CO 2 and negligible H 2 O (0.04 wt%) indicates fluid-present carbonic conditions with a CO 2 activity near 1.0 at peak or near-peak pressures of 10.5–11.3 kbar under UHT temperatures of 950–1050 °C. The measured H 2 O content of the cordierite in the metapelite is far too low to be consistent with partial melting at 1000–1050 °C, implying either that nearly all of any H 2 O originally in this cordierite under UHT conditions was lost during post-peak cooling or that the cordierite was formed after migmatization. The high level of CO 2 required to ensure fluid saturation of the c. 11 kbar UHT cordierite is proposed to have been derived from an external, possibly mantle, source.
Publisher: Elsevier BV
Date: 12-2022
Publisher: Informa UK Limited
Date: 05-08-2022
Publisher: Elsevier BV
Date: 09-2014
Publisher: Geological Society of America
Date: 2020
Publisher: Geological Society of South Africa
Date: 06-2006
Publisher: Geological Society of America
Date: 2011
Publisher: Wiley
Date: 10-02-2021
DOI: 10.1002/GJ.4094
Abstract: We present in‐situ zircon laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) U–Pb ages, whole‐rock geochemistry, and Sr–Nd–Pb–Hf isotopes of the Mugagangri monzogranite in the southern margin of the Qiangtang Block, Tibet, western China. The zircons yield a U–Pb age of ca. 123 Ma. The hornblende‐bearing monzogranite shows metaluminous to weak peraluminous and high‐K calc‐alkaline characteristics exemplified by high silica (SiO 2 = 67.57–70.57 wt%), high aluminium (Al 2 O 3 = 14.68–15.78 wt%), high potassium (K 2 O = 4.00–5.14 wt%), high alkali (K 2 O + Na 2 O = 7.88–8.62 wt%), and low calcium contents (CaO = 1.72–2.17 wt%), with the aluminium saturation index (A/CNK) ranging from 0.98 to 1.09, suggesting that the Mugagangri monzogranite is a metaluminous to weak peraluminous I‐type high‐K calc‐alkaline granite. Geochemically, similar to the arc magmas, the monzogranite is enriched in large‐ion lithophile elements, and relatively depleted in high‐field‐strength elements. The monzogranite displays relatively high ( 87 Sr/ 86 Sr) i values (0.70972–0.71240), uniform ε Nd ( t ) values (−2.24 to −3.40), variable zircon ε Hf ( t ) values (−14.1 to +8.0), and high radiogenic Pb isotopic values ( 206 Pb/ 204 Pb = 18.588–18.790, 207 Pb/ 204 Pb = 15.616–15.642, and 208 Pb/ 204 Pb = 38.838–39.053). These geochemical characteristics indicate that the monzogranite was derived from a mixed source comprising ancient crustal and mantle materials, and experienced fractional crystallization during emplacement. We propose that the parental magma of the Mugagangri monzogranite was most likely generated during northward subduction of the Bangong Co‐Nujiang Meso‐Tethys Ocean.
Publisher: Elsevier BV
Date: 12-2021
Publisher: Elsevier BV
Date: 05-2020
Publisher: Society of Economic Geologists
Date: 09-2017
Publisher: Elsevier BV
Date: 10-2019
Publisher: Academy of Science of South Africa
Date: 29-01-2016
DOI: 10.4314/WSA.V42I1.12
Publisher: Geological Society of America
Date: 2011
Publisher: Elsevier BV
Date: 07-1998
Publisher: Springer International Publishing
Date: 2019
Publisher: Wiley
Date: 12-09-2019
DOI: 10.1002/GJ.3639
Publisher: Elsevier BV
Date: 02-2012
Publisher: Elsevier BV
Date: 06-2021
Publisher: Elsevier BV
Date: 04-2010
Publisher: Wiley
Date: 12-04-2020
DOI: 10.1002/GJ.3834
Publisher: MDPI AG
Date: 09-11-2021
DOI: 10.3390/MIN11111243
Abstract: The Guangxi Zhuang Autonomous Region is an important manganese ore district in Southwest China, with manganese ore resource reserves accounting for 23% of the total manganese ore resource reserves in China. The Xialei manganese deposit (Daxin County, Guangxi) is the first super-large manganese deposit discovered in China. The Mn oxide in the supergene oxidation zone of the Xialei deposit was characterized using scanning electron microscopy (SEM), energy spectrometer (EDS), transmission electron microscopy (TEM, HRTEM), and X-ray diffraction analysis (XRD). The Mn oxides have a gray-black/steel-gray color, a semi-metallic-earthy luster, and appear as oolitic, pisolitic, banded, massive, and cellular textures. Scanning electron microscopy images show that the manganese oxide minerals are present as fine-spherical particles with an earthy surface. TEM and HRTEM indicate the presence of oriented bundled and staggered nanorods, and nanopores between the crystals. The Mn oxide ore can be classified into two textural types: (1) oolitic and pisolitic (often with annuli) Mn oxide, and (2) massive Mn oxide. Pyrolusite, cryptomelane, and hollandite are the main Mn oxide minerals. The potassium contents of cryptomelane and pyrolusite are discussed. The unit cell parameters of pyrolusite are refined.
Publisher: Elsevier BV
Date: 07-2022
Publisher: Wiley
Date: 03-03-2019
DOI: 10.1002/GJ.3473
Publisher: Academy of Science of South Africa
Date: 08-2011
Publisher: Informa UK Limited
Date: 14-10-2022
Publisher: Elsevier BV
Date: 03-2022
Publisher: Elsevier BV
Date: 09-2022
Publisher: Elsevier BV
Date: 02-2020
Publisher: Elsevier BV
Date: 10-2014
Publisher: Elsevier BV
Date: 2016
Publisher: Geological Society of London
Date: 05-2012
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 02-2020
Publisher: GeoScienceWorld
Date: 05-2020
DOI: 10.15372/RGG2019128
Abstract: —Supercontinents are a unique feature of the planet Earth. A brief review of supercontinents formed since the Archean shows that before the Eocambrian, supercontinents, notably Gondwana and Rodinia, amalgamated through high-temperature mobile belts, all of them containing ultrahigh-temperature granulite occurrences. During the final stage of the amalgamation, the lower continental crust was brought to magmatic temperature (from ~900 to more than 1000 °C) during a variable time span, from less than 10 Ma in the recent shortlived orogens to more than 150 Ma in the Eocambrian (Gondwana) or Neoproterozoic (Rodinia) long-lived orogens. Ultrahigh-temperature granulites worldwide contain the same types of fluid inclusions, namely, dense CO2 and highly saline aqueous brines. The fluid amount in the peak metamorphic conditions is indicated by the amount of preserved fluid inclusions (especially CO2) and by the secondary effects caused by the fluids when they left the lower crust, including regional feldspathization, albitization or scapolitization, and formation of megashear zones, either oxidized (quartz–carbonate) or reduced (graphite veins). While some fluids may be locally derived either from mineral reactions or from inherited sediment waters, carbon isotope signature and petrographical arguments suggest that most fluids, both CO2 and high-salinity brines, are derived from carbonatite melts resulting from partial melting of metasomatized mantle. Ultrahigh-temperature metamorphism is critical for supercontinent amalgamation, but the associated fluid causes instability and disruption shortly after amalgamation.
Publisher: Elsevier BV
Date: 2001
Publisher: Geological Society of South Africa
Date: 12-2019
Abstract: The paper reviews published and unpublished geological data pertaining to the structural and metamorphic controls, rock types, characteristic features, source, and timing of hypozonal orogenic gold mineralization in the Giyani Goldfield. The Giyani Goldfield includes the NW domain of the & .0 Ga Giyani greenstone belt (GGB) at the northern edge of the Kaapvaal Craton and the southern retrograde hydrated domain of the juxtaposed Southern Marginal Zone (SMZ) of the ca. 2.72 Ga Limpopo Complex (LC). Mineralization at all gold mines and gold prospects of the Giyani Goldfield is structurally controlled and closely associated with the Hout River shear zone (HRSZ) and associated smaller shear zones suggesting a specific tectonic setting. This tectonic setting is the direct consequence of thrusting the SMZ of the LC against and over the adjacent GGB at the position of the steeply north-dipping (south verging) HRSZ during the exhumation stage of the ca. 2.72 to 2.69 Ga Limpopo orogeny followed by regional retrograde hydration of the southern part of the SMZ at ca. 2.68 to 2.62 Ga. This tectonic setting offers an explanation for a deep-seated crustal source for gold and for the concentration of orogenic gold mineralization within specific structural features located within the Giyani Goldfield. This tectonic setting also explains the lithological, structural and metamorphic complexity, metasomatic alteration and post-peak metamorphic timing of gold mineralization. Finally, it provides important clues with regards to a crustal source for gold mineralizing fluids and the identification of new potential targets for gold exploration in the Giyani Goldfield.
Publisher: Elsevier BV
Date: 11-2012
Publisher: Academy of Science of South Africa
Date: 30-04-2013
DOI: 10.4314/WSA.V39I2.18
Publisher: Elsevier BV
Date: 06-2022
Publisher: Elsevier BV
Date: 11-2021
Publisher: Springer Science and Business Media LLC
Date: 20-10-2015
Publisher: Geological Society of London
Date: 31-05-2017
DOI: 10.1144/SP453.4
Publisher: Elsevier BV
Date: 06-2017
Publisher: Geological Society of America
Date: 1999
Publisher: Elsevier BV
Date: 05-2020
No related grants have been discovered for Jan Marten Huizenga.