Thermochronological constraints on the exhumation history of the Carboniferous Katebasu gold deposit, western Tianshan Gold Belt, NW China

2021 ◽  
pp. SP516-2020-201
Author(s):  
WeiCe Zhao ◽  
XiaoBo Zhao ◽  
ChunJi Xue ◽  
Reimar Seltmann ◽  
Alla Dolgopolova ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Cooling History ◽  
Western Tianshan ◽  
Three Phase ◽  
History Of ◽  
Two Phases ◽  
Uplift And Erosion ◽  
Exhumation History

AbstractThe western Tianshan Gold Belt hosts numerous giant and large gold deposits that have been formed during the late Paleozoic amalgamation of the Tianshan orogen. However, little is known about their exhumation histories during the Mesozoic to Cenozoic intracontinental evolution of the orogen. The Carboniferous Katebasu orogenic gold deposit in northwestern China is a new gold discovery within the western Tianshan Gold Belt, and it shares many similarities with other orogenic gold deposits in the belt. In this contribution, new 40Ar/39Ar and (U-Th)/He ages were combined with previous geochronology and numerical modeling to quantify its post-Carboniferous cooling and exhumation history. The results revealed a three-phase cooling history and two phases of post-mineralization exhumation. We suggest that a large volume (∼0.8 km) of the mineralized roof parts of the Katebasu deposit might have been removed during uplift and erosion, whereas significant ore reserves could still exist at depth. The large erosion depth of the Katebasu gold deposit in the Nalati Range of the Chinese western Tianshan also signifies that shallow-emplaced porphyry and epithermal systems that formed prior to Permo-Triassic uplift might have been largely eroded.

scholarly journals Genesis of the Koka Gold Deposit in Northwest Eritrea, NE Africa: Constraints from Fluid Inclusions and C-H-O-S Isotopes

2019 ◽  
Author(s):  
Kai Zhao ◽  
Huazhou Yao ◽  
Jianxiong Wang ◽  
Ghebsha Fitwi Ghebretnsae ◽  
Wenshuai Xiang ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Meteoric Water ◽  
Gold Mineralization ◽  
Early Stage ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Quartz Veins ◽  
Three Phase ◽  
Igneous Origin ◽  
Ne Africa

The Koka gold deposit is located in the Elababu shear zone between the Nakfa terrane and the Adobha Abiy terrane, NW Eritrea. Based on the paragenetic study two main stages of gold mineralization were identified in the Koka gold deposit: 1) an early stage of pyrite-chalcopyrite-sphalerite-galena-gold-quartz vein; and 2) a second stage of pyrite-quartz veins. NaCl-aqueous inclusions, CO2-rich inclusions, and three-phase CO2-H2O inclusions occur in the quartz veins at Koka. The ore-bearing quartz veins formed at 268℃, from NaCl-CO2-H2O(-CH4) fluids averaging 5 wt% NaCl eq. The ore-forming mechanisms include fluid immiscibility during stage I, and mixing with meteoric water during stage II. Oxygen, hydrogen and carbon isotopes suggest that the ore-forming fluids originated as mixtures of metamorphic water, meteoric water and magmatic water, whereas sulfur isotope suggest an igneous origin. Features of geology and ore-forming fluid at Koka deposit are similar to those of orogenic gold deposits, suggesting the Koka deposit might be an orogenic gold deposit related to granite.

scholarly journals Genesis of the Koka Gold Deposit in Northwest Eritrea, NE Africa: Constraints from Fluid Inclusions and C–H–O–S Isotopes

Minerals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 201 ◽  
Author(s):  
Kai Zhao ◽  
Huazhou Yao ◽  
Jianxiong Wang ◽  
Ghebsha Fitwi Ghebretnsae ◽  
Wenshuai Xiang ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Gold Mineralization ◽  
Early Stage ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Quartz Veins ◽  
Second Stage ◽  
Three Phase ◽  
Igneous Origin ◽  
Ne Africa

: The Koka gold deposit is located in the Elababu shear zone between the Nakfa terrane and the Adobha Abiy terrane, NW Eritrea. Based on a paragenetic study, two main stages of gold mineralization were identified in the Koka gold deposit: (1) an early stage of pyrite–chalcopyrite–sphalerite–galena–gold–quartz vein; and (2) a second stage of pyrite–quartz veins. NaCl-aqueous inclusions, CO2-rich inclusions, and three-phase CO2–H2O inclusions occur in the quartz veins at Koka. The ore-bearing quartz veins formed at 268 °C from NaCl–CO2–H2O(–CH4) fluids averaging 5 wt% NaCl eq. The ore-forming mechanisms include fluid immiscibility during stage I, and mixing with meteoric water during stage II. Oxygen, hydrogen, and carbon isotopes suggest that the ore-forming fluids originated as mixtures of metamorphic water and magmatic water, whereas the sulfur isotope suggests an igneous origin. The features of geology and ore-forming fluid at the Koka deposit are similar to those of orogenic gold deposits, suggesting that the Koka deposit might be an orogenic gold deposit related to granite.

Evolution of the Miocene Ailaoshan orogenic gold deposits, southeastern Tibet, during a complex tectonic history of lithosphere-crust interaction

2019 ◽  
Vol 55 (6) ◽  
pp. 1085-1104 ◽  
Author(s):  
Qingfei Wang ◽  
David I. Groves ◽  
Jun Deng ◽  
Huajian Li ◽  
Lin Yang ◽  
...  
Keyword(s):  
Gold Deposits ◽  
Orogenic Gold ◽  
Orogenic Gold Deposits ◽  
Tectonic History ◽  
History Of ◽  
Southeastern Tibet

The early exhumation history of the Western Tianshan UHP metamorphic belt, China: New constraints from titanite U-Pb geochronology and thermobarometry

2018 ◽  
Vol 36 (5) ◽  
pp. 631-651 ◽  
Author(s):  
Lijuan Zhang ◽  
Xu Chu ◽  
Lifei Zhang ◽  
Bin Fu ◽  
Thomas Bader ◽  
...  
Keyword(s):  
Metamorphic Belt ◽  
Western Tianshan ◽  
History Of ◽  
Exhumation History

scholarly journals Cooling and exhumation of the Late Paleozoic Tulasu epithermal gold system, Western Tianshan, NW China: implications for preservation of Pre-Mesozoic epithermal deposits

2020 ◽  
pp. jgs2020-099
Author(s):  
Xiao-Bo Zhao ◽  
Chun-Ji Xue ◽  
Wei-Ce Zhao ◽  
Reimar Seltmann ◽  
David T.A. Symons ◽  
...  
Keyword(s):  
Volcanic Rocks ◽  
Gold Deposits ◽  
Late Paleozoic ◽  
Epithermal Gold ◽  
Nw China ◽  
Epithermal Deposits ◽  
Tectonic Events ◽  
Western Tianshan ◽  
Shallow Crust ◽  
Exhumation History

Epithermal gold deposits are rarely well preserved in pre-Mesozoic terranes because of their low-temperature mineralization at shallow crust levels, and they are easily destroyed by subsequent erosion or depleted by tectonic events. However, several significant Late Paleozoic epithermal gold deposits have been found in the Tulasu volcanic basin in NW China, forming one of the largest gold districts in the western Tianshan Orogen. Here, we report a new 40Ar/39Ar age from a monzonite porphyry enclave hosted in andesite and apatite fission track data for 10 volcanic rocks from the Tulasu basin. These data, combined with the previous dataset, are used to perform inverse thermal modelling to quantify the district's cooling and exhumation history. Our modelling indicates a phase of burial reheating during Late Paleozoic sedimentation following mineralization, a subsequent rapid exhumation in the Jurassic to Early Cretaceous (c. 196–128 Ma), and a slow exhumation to the present. The Mesozoic exhumation is likely related to the far-field effects of the Cimmerian orogeny along the southern Eurasian margin. Therefore, we suggest that the rapid burial by thick sediments and the slow protracted exhumation after mineralization were crucial for the preservation of the Paleozoic epithermal gold system at Tulasu.

scholarly journals Fluid Inclusion Study of the Penjom, Tersang, and Selinsing Orogenic Gold Deposits, Peninsular Malaysia

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 111
Author(s):  
Charles Makoundi ◽  
Khin Zaw ◽  
Zakaria Endut
Keyword(s):  
Fluid Inclusion ◽  
Gold Deposit ◽  
Peninsular Malaysia ◽  
Gold Deposits ◽  
Black Shales ◽  
Orogenic Gold ◽  
Fluid Inclusion Study ◽  
Laser Raman ◽  
Orogenic Gold Deposits ◽  
Basin Scale

Ore-forming fluids in the auriferous district of the Central gold belt in Peninsular Malaysia were studied for their temperature, salinity, and relationship to the surrounding geology. Microthermometric analysis carried out showed homogenisation temperatures range from 210 to 348 °C (Tersang), between 194 and 348 °C (Selinsing), and from 221 to 346 °C (Penjom). Salinities range from 2.41 to 8.95 wt % NaCl equiv (Tersang), between 1.23 and 9.98 wt % NaCl equiv (Selinsing), and from 4.34 to 9.34 wt % NaCl equiv (Penjom). Laser Raman studies indicated that at the Tersang gold deposit, most inclusions are either pure or nearly pure CO2-rich (87–100 mol %), except for one inclusion, which contains CH4 gas (13 mol %). In addition, at Selinsing, most inclusions are CO2-rich (100 mol %). However, an inclusion was found containing CO2 (90 mol %), with minor N2 and CH4. Additionally, at the Penjom gold deposit, most fluid inclusions are CO2-rich (91–100 mol %), whereas one fluid inclusion is N2-rich (100 mol %) and another one has minor N2 and CH4. At a basin scale, homogenisation temperatures against salinity suggests an isothermal mixing of fluids. Most fluids are CO2-rich and are interpreted to be of metamorphic origin. The evidence further indicates involvement of magmatic fluids that is supported by the association of sandstone and carbonaceous black shales with magmatic rocks, such as rhyolite, rhyolite-dacite, and trachyte-andesite at the Tersang and Penjom orogenic gold deposits.

Formation temperature and ages of the True North orogenic gold deposit in Manitoba, Canada

2021 ◽  
pp. SP516-2020-111
Author(s):  
P. Alexandre ◽  
M. Fayek
Keyword(s):  
Gold Deposit ◽  
Structural Control ◽  
Age Groups ◽  
Oxygen Isotopic Composition ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Laser Fusion ◽  
Formation Temperature ◽  
Orogenic Gold Deposit ◽  
Recent Developments

AbstractThe True North orogenic gold deposit is situated in the 2.99-2.70 Ga Rice Lake greenstone belt near Bissett (Manitoba, Canada). This belt is the western equivalent of northern Ontario's Abitibi gold-producing region. The lithology and alteration, structural control, geochronological framework, and ore geology of the True North orogenic gold deposit have been addressed, but its formation temperature and age are poorly constrained.The deposit's gold-bearing veins are composed mostly of quartz (40 to 80%), ankerite (20 to 30%), and albite (5 to 25%), with minor muscovite, sericite, chlorite, and calcite. Sulfide minerals are dominated by pyrite and chalcopyrite and with minor pyrrhotite; native gold appears as inclusions in sulfides or as free gold. In general, most of the major minerals, the sulfides, and gold all precipitated during the main ore stage.The oxygen isotopic composition of co-existing quartz-albite and quartz-ankerite couples were used to calculate a formation temperature of approximately 230 °C for these minerals, which is comparable to the nearby 007 gold deposit. These temperatures are on the low end of the temperature range reported for orogenic gold deposits. 40Ar/39Ar geochronology (single grain laser fusion of muscovite and sericite) revealed the presence of two age groups, at 2441.2 ± 8.8 Ma and 2483.1 ± 10.2 Ma, approximately 200 My lower than the age of the main collision-related deformation within the Rice Lake belt. These ages indicate that the True North deposit was clearly post-orogenic, similar to vein gold deposits elsewhere, and was likely produced by the emplacement of the Huronian Supergroup and the thermal effects of the Matachewan LIP which has the same ages. It is suggested that the True North deposit may belong to a descriptive category of post-orogenic low-temperature quartz-carbonate-albite vein gold deposit, more in line with recent developments in classification schemes.

scholarly journals The Perron Gold Deposit, Archean Abitibi Belt, Canada: Exceptionally High-Grade Mineralization Related to Higher Gold-Carrying Capacity of Hydrocarbon-Rich Fluids

Minerals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1066
Author(s):  
Damien Gaboury ◽  
Dominique Genna ◽  
Jacques Trottier ◽  
Maxime Bouchard ◽  
Jérôme Augustin ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Trace Element ◽  
Gold Deposit ◽  
Gold Mineralization ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Magmatic Fluid ◽  
High Grade ◽  
Host Rocks ◽  
Mineralizing Fluids

The Perron deposit, an Archean orogenic gold deposit located in the Abitibi belt, hosts a quartz vein-type gold-bearing zone, known as the high-grade zone (HGZ). The HGZ is vertically continuous along >1.2 km, and is exceptionally rich in visible gold throughout its vertical extent, with grades ranging from 30 to 500 ppm. Various hypotheses were tested to account for that, such as: (1) efficient precipitating mechanisms; (2) gold remobilization; (3) particular fluids; (4) specific gold sources for saturating the fluids; and (5) a different mineralizing temperature. Host rocks recorded peak metamorphism at ~600 °C based on an amphibole geothermometer. Visible gold is associated with sphalerite (<5%) which precipitated at 370 °C, based on the sphalerite GGIMFis geothermometer, during late exhumation of verticalized host rocks. Pyrite chemistry analyzed by LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) is comparable to classical orogenic gold deposits of the Abitibi belt, without indication of a possible magmatic fluid and gold contribution. Comparison of pyrite trace element signatures for identifying a potential gold source was inconclusive to demonstrate that primary base-metal rich volcanogenic gold mineralization, dispersed in the host rhyolitic dome, could be the source for the later formation of the HGZ. Rather, nodular pyrites in graphitic shales, sharing similar trace element signatures with pyrite of the HGZ, are considered a potential source. The most striking outcome is the lack of water in the mineralizing fluids, implying that gold was not transported under aqueous complexes, even if fugacity of sulfur (−6) and oxygen (−28), and pH (~7) are providing the best conditions at a temperature of 350 °C for solubilizing gold in water. Fluid inclusions, analyzed by solid-probe mass spectrometry, are rather comparable to fossil gas composed mostly of hydrocarbons (methane and ethane and possibly butane and propane and other unidentified organic compounds), rich in CO2, with N2 and trace of Ar, H2S, and He. It is interpreted that gold and zinc were transported as hydrocarbon-metal complexes or as colloidal gold nanoparticles. The exceptional high content of gold and zinc in the HGZ is thus explained by the higher transporting capacity of these unique mineralizing fluids.

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