Characterization of Illite Clays associated with the Sinongduo low sulfidation epithermal deposit, Central Tibet using field SWIR spectrometry

Guo, Na; Guo, Wenbo; Shi, Wang; Huang, Yiru; Guo, Yuqing; Lian, Dunmei

doi:10.1016/j.oregeorev.2019.103228

Cited by 15 publications

(5 citation statements)

References 31 publications

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“…By comparison, white micas from the Pebble porphyry deposit largely have ISM values <1.0, except for a “sericite (minor pyrophyllite)” sample which reported an ISM value of 3.65 (Harraden et al ., 2013). As well as having generally much higher crystallinity and therefore higher formation temperatures than Pebble porphyry system white micas, MQP white micas have higher crystallinity than all white micas from the Cerro La Mina high sulfidation epithermal deposit whose ISM ratios are all <1.6 (Jansen et al ., 2017: Figure 6), and those reported from other epithermal vein gold deposits with ISM ratios <1.0 (Victoria; Chang et al ., 2011; Sinongduo; Guo et al ., 2020; Shihu; Yao et al ., 2021).…”

Section: Discussionmentioning

confidence: 99%

Chemical and short‐wave infrared characteristics of white mica associated with the Gajah Tidur porphyry copper system at the deep Grasberg Cu—Au—(Mo) deposit, Indonesia

et al. 2022

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The Grasberg Cu—Au—(Mo) deposit comprises the shallower Main Grasberg porphyry Cu—Au and the deeper Gajah Tidur (GT) porphyry Cu—Mo—(Au) systems. The GT porphyry preserves various types of white mica whose geochemical variations provide insights into the white mica‐dominated alteration of porphyry systems. The white mica assemblages within the GT porphyry system comprise: (1) muscovite‐anhydrite‐chlorite (MAC), (2) muscovite‐chlorite‐anhydrite (MCA), and (3) muscovite‐quartz ± pyrophyllite (MQP). These assemblages display zonation from central and deep parts of the system to its shallower and peripheral parts. The MAC alteration white micas are characterized by high Na, Fe, Ti, and V concentrations, and with short‐wave infrared Al—OH absorption wavelengths of 2203–2208 nm. The MCA white micas have higher Mg content than the other two GT white mica assemblages but similar Al—OH absorption wavelengths to the MAC white micas. The MQP alteration white micas have low Na, Fe, Mg, and Ti, but relatively high Si, Al, and F, and Al—OH absorption wavelengths are largely shorter than 2202 nm. We interpret that the high Fe and Ti content of the MAC white micas is due to inheritance of these elements from mafic minerals they replaced. The higher Fe content of these white micas explain their longer wavelength Al—OH absorption positions relative to the MQP white micas. In contrast, lower Fe content and shorter Al—OH wavelengths of the MQP white micas are caused by their higher Si and Al content, which reduces iron occupancy in the white mica crystal structure. White micas in this assemblage formed at lower temperature and probable lower pH condition that may have led to a replacement of Fe by Al. The short‐wave infrared Al—OH position of white mica together with the associated hydrothermal assemblage can be used as a proximitor for porphyry Cu hydrothermal centres. White mica associated with chlorite, anhydrite, and chalcopyrite, which commonly occur overprinting or adjacent to the potassic alteration center, are characterized by Al—OH absorption positions at 2200–2215 nm. By contrast, white mica associated with quartz‐pyrite are characterized by Al—OH wavelengths shorter than 2202 nm. In the distal part of porphyry Cu system, white micas may be associated with chlorite and have Al—OH absorption positions longer than 2204 nm.

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Section: Discussionmentioning

confidence: 99%

Chemical and short‐wave infrared characteristics of white mica associated with the Gajah Tidur porphyry copper system at the deep Grasberg Cu—Au—(Mo) deposit, Indonesia

et al. 2022

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“…1b). The detailed deposit geology of the Sinongduo epithermal deposit was introduced by Li et al (2019), Guo et al (2020) and Yang et al (2020).…”

Section: Deposit Geologymentioning

confidence: 99%

Genesis of the Sinongduo Carbonate‐hosted Pb‐Zn‐Ag Deposit in the Central Lhasa Terrane, Tibet

Ran

Tang

Yang

et al. 2023

Acta Geologica Sinica (Eng)

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The Sinongduo mining region includes two types of mineralizations: the epithermal and the carbonate‐hosted Pb‐Zn‐Ag deposits. Despite being studied for many years, the ore formation process and genesis of the carbonate‐hosted Pb‐Zn‐Ag deposits remain poorly understood. The Pb‐Zn‐Ag ore bodies occur as veins and are hosted by limestone and dolostone of the Permian Xiala Formation. Three sulfide mineralization substages have been identified at the Sinongduo carbonate‐hosted deposit. Indium coupled with Cu, Co and Sn was incorporated into sphalerite as substitutions: 2Zn2+ ↔ Cu+ + In3+, (3n/2 + 1)Zn2+ ↔ Co2+ + nIn3+ or (2n + 1)Zn2+ ↔ Co2+ + n(Cu+ + In3+) (n > 1) and 4Zn2+ ↔ Sn2+ + 2In3+. Sphalerite and pyrite in the mineralization stage display δ34S values in a narrow range of +5.7‰ to +11.3‰, which are similar to those of Palaeocene igneous rocks, indicative of a magmatic source of sulfur. We present systematic carbon‐hydrogen‐oxygen isotope results that further support a magmatic source for the ore‐forming fluids that were influenced by meteoric water. Furthermore, the Pb isotope compositions of sulfide minerals in the Sinongduo carbonate‐hosted deposit overlap with the values of coeval Linzizong volcanic rocks and are similar to those of Indian Ocean sediments, indicating upper crustal sources of metals. We conclude that the Sinongduo carbonate‐hosted Pb‐Zn‐Ag deposit is a medium‐ to low‐temperature magmatic‐hydrothermal deposit related to Linzizong magmatism.

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“…The alteration types in low-sulfidation epithermal deposits are classified as propylitic, argillic, advanced argillic, silicic, and sericitic types, respectively [13]. For example, the alteration mineral association of quartz ± calcite ± adularia ± illite in low-sulfidation deposits, including Au-Ag, or Ag-Pb-Zn ores [18,19]. Globally, the various alteration types occur at different intensities in the silicified vein [20][21][22][23], monzonite [24], diorite porphyry [5,6], granite-granodiorite porphyry [22,25,26], and metamorphic [22,27]-volcanic rocks [8,21,28].…”

Section: Introductionmentioning

confidence: 99%

“…The diagram shows that the vein-veinlet silicification zone in the study area contains mostly illite and smectite; quartz-feldspar porphyries with muscovite, biotite, and smectite; and quartz-mica schists with illite, muscovite, biotite, and smectite (Figure14a). Based on the Al2 O 3 -(Na 2 O + K 2 O)-(Fe 2 O 3 + MgO)-K 2 O triple diagram[18], the vein-veinlet silicification zone and quartz-mica schist samples are classified as falling within the potassium silicate (K-silicate), propylitic, and sericitic categories. The quartz-feldspar porphyry samples, however, are mostly classified as falling within the propylitic category and, to a lesser extent, the potassium silicate category (Figure14b).…”

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confidence: 99%

Petrography and Geochemistry of Hydrothermal Alteration in the Low-Sulfidation Epithermal Kestanelik Au Deposit, Biga Peninsula, NW Turkey

Kiray,

Cengiz

2024

Minerals

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In this study, the facies and degrees of hydrothermal alteration related to the low-sulfidation epithermal Kestanelik Au deposit in the Biga Peninsula metallogenic province are identified through petrographic studies and analysis of geochemical characteristics, such as mass changes, molar element ratios, and alteration indices. The gold mineralization is located in silicified zones containing veins and stockwork veinlets of silica. In the Kestanelik Au deposit, common hydrothermal alteration is mainly found in the Permian-Upper Cretaceous Çamlıca basement metamorphics and the Eocene granodiorite, and less often in the Eocene Şahinli volcanic rocks of the Karabiga Massif on the Peninsula. Based on mineralogical and geochemical studies conducted on altered samples, four different alteration facies are defined as silicic, sericitic, argillic, and propylitic, which show remarkable differences in the behavior of REEs, Si, K, Al, Na, and Ca elements. The hydrothermal fluids that caused alteration in the Kestanelik Au mineralization and host rocks had low REE contents because of REE mobilization. In addition, the kaolinization of feldspars and micas, and the chloritization of biotite and feldspars, may have caused negative Eu anomalies. The characterization of rocks subjected to hydrothermal alteration that are most influenced by diverse K-metasomatism with the largest K gains and losses in Na–Ca is illustrated by molar element ratio plots. Depending on the intensity of K-metasomatism, gold mineralization increases with increasing K trends toward gold ore veins. In the Kestanelik Au field, the argillic, sericitic, and propylitic alteration types from the zones enclosing the Au ore veins are revealed using the Ishikawa alteration index and chlorite–carbonate–pyrite index. Mass changes in the altered rocks indicate that there are gains in Si, K, and Al, and losses in Na and Ca with the increasing intensity of alteration toward the ore veins. The results confirm the presence of silicic and K–metasomatic (sericite and argillic) and propylitic (Fe-rich chloride) alteration zoning extending from the inner regions to the outer regions, which characterize the epithermal ore systems.

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Characterization of Illite Clays associated with the Sinongduo low sulfidation epithermal deposit, Central Tibet using field SWIR spectrometry

Cited by 15 publications

References 31 publications

Chemical and short‐wave infrared characteristics of white mica associated with the Gajah Tidur porphyry copper system at the deep Grasberg Cu—Au—(Mo) deposit, Indonesia

Chemical and short‐wave infrared characteristics of white mica associated with the Gajah Tidur porphyry copper system at the deep Grasberg Cu—Au—(Mo) deposit, Indonesia

Genesis of the Sinongduo Carbonate‐hosted Pb‐Zn‐Ag Deposit in the Central Lhasa Terrane, Tibet

Petrography and Geochemistry of Hydrothermal Alteration in the Low-Sulfidation Epithermal Kestanelik Au Deposit, Biga Peninsula, NW Turkey

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