Multi-Stage Evolution of Gold-Bearing Hydrothermal Quartz Veins at the Mokrsko Gold Deposit (Czech Republic) Based on Cathodoluminescence, Spectroscopic, and Trace Elements Analyses

We performed a detailed analysis of hydrothermal quartz at the Mokrsko gold deposit (Čelina, Mokrsko-East, and Mokrsko-West deposits). Twenty-one samples were studied by scanning electron microscopy cathodoluminescence (CL) imagining, CL emission spectra and trace elements were measured on six selected samples. Four quartz growth generations Q1 to Q4 were described. Homogeneous early blue CL Q1 with initial emission spectra at 380 and 500 nm was observed at the Čelina deposit with typical titanium concentrations in the range of 20–50 ppm. Hydrothermal quartz at Mokrsko-West, which also includes early Q1, late subhedral faces of yellow CL Q2, and microfissures of greenish CL Q3 (both 570 nm), is characterized by titanium depletion. The titanium concentration is comparable to previous studies of crystallization temperatures proving titanium concentration in quartz as a good geothermal indicator. Q4, developed in microfissures only at Čelina, has no visual CL effect. Mokrsko-West is specific in comparison to Mokrsko-East and Čelina by germanium enrichments in hydrothermal quartz (up to 17 ppm) and the presence of fluorite. Tectonic (sheeted veinlets system, regional tectonic setting) and geochemical (germanium in quartz, the presence of fluorite) characteristics of the quartz veins link the late mineralization stages at the Mokrsko-West deposit to the temporally related Blatná intrusive suite.

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Genetic relationship between greisenization and Sn-W mineralizations in vein and greisen deposits: Insights from the Panasqueira deposit (Portugal)

BSGF - Earth Sciences Bulletin ◽

10.1051/bsgf/2020046 ◽

2021 ◽

Vol 192 ◽

pp. 2

Author(s):

Gaëtan Launay ◽

Stanislas Sizaret ◽

Philippe Lach ◽

Jérémie Melleton ◽

Éric Gloaguen ◽

...

Keyword(s):

Trace Elements ◽

Hydrothermal System ◽

Quartz Vein ◽

Major And Trace Elements ◽

Multivariate Statistical ◽

Quartz Veins ◽

Hydrothermal Quartz ◽

Multivariate Statistical Approach ◽

Cooling Trend ◽

Ti In Quartz

The W-Sn Panasqueira ore deposit is a magmatic-hydrothermal system, which includes a high grade quartz-vein type mineralization and underneath disseminated greisen-type mineralization located in the upper part of a two-mica granite. We investigate genetic and chronological relationships between greisenization of the Panasqueira granite and the formation of ore-bearing quartz veins by monitoring major and trace elements variations in quartz-muscovite assemblages composing the two-mica granite, greisen and ore-bearing quartz veins. Greisen is marked by an overall depletion in Mg, Ti, Ca, Na, Ba, Sr, REE and enrichment in Fe, Li, Rb, Cs, Sn, W that reflect the breakdown of feldspars and biotite and implication of W-Sn-bearing fluids during greisenization. Muscovite from greisen and mineralized quartz veins are enriched in granophile elements (F, Rb, Cs, Li, Sn, W and Zn) compared to magmatic muscovite from the two-mica granite. Trace elements contents in quartz depict evolutionary trends with progressive enrichment in Ge and B and depletion in Al, Ti and Li between magmatic and hydrothermal quartz that emphasize the progressive evolution and cooling of the magmatic-hydrothermal system of Panasqueira. Multivariate statistical approach applied on quartz and muscovite data demonstrates similarities in composition between quartz and muscovite from greisen with those composing ore-bearing quartz veins. These similarities suggest that greisenization and the formation of mineralized veins result from the same hydrothermal event and derived from the same source of hydrothermal fluids. Apatite from greisen and quartz vein yielded respectively U-Pb ages of 292 ± 10 Ma and 295 ± 5 Ma confirming that greisenization and the formation of mineralized veins occurred roughly at the same time. These ages also overlap with the cooling age of the Panasqueira granite (296 ± 4 Ma), indicating a temporal and genetic link between greisenization, W-Sn mineralization and the granite crystallization. Temperatures of the magmatic-hydrothermal system constrained by Ti-in quartz thermometry depicts a cooling trend from magmatic quartz of granite (700–600 °C) to hydrothermal quartz of greisen (500–400 °C) and veins (450–350 °C). These results provide evidences that greisenization and the formation of W-Sn bearing quartz veins occurred at the magmatic-hydrothermal transition, during which orthomagmatic fluids rich in volatils, incompatible elements and metals (W and Sn) were exsolved at the final stage of solidification of the Panasqueira two-mica granite.

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Characteristics of genetic mineralogy of pyrite and quartz and their indicating significance in the Gaosongshan Gold Deposit, Heilongjiang Province, NE China

Earth Sciences Research Journal ◽

10.15446/esrj.v22n4.57512 ◽

2018 ◽

Vol 22 (4) ◽

pp. 301-318

Author(s):

Huiqing Geng ◽

Xuexiang Gu ◽

Yongmei Zhang

Keyword(s):

Trace Elements ◽

Rare Earth ◽

Rare Earth Elements ◽

Gold Deposit ◽

Volcanic Rocks ◽

Forming Process ◽

Quartz Veins ◽

Epithermal Gold Deposit ◽

Basic Volcanic ◽

P Type

The Gaosongshan epithermal gold deposit in Heilongjiang, Northeast China, is hosted by the Lower Cretaceous intermediate-basic volcanic rocks. Three auriferous quartz veins including eleven gold orebodies were all discovered in tectonoclastic zones. Genetic mineralogy study including the thermoelectricity, rare earth elements and trace elements of pyrite and rare earth elements of quartz were carried out. Thermoelectric conductive type of pyrite is mainly N-P type. Calculating the thermoelectric parameters XNP and denudation percentage γ of pyrites from orebodies 1-I, 2-II and 2-IV, suggests that gold orebodies are all eroded to their middle-lower parts. The variable range of Co concentrations (51.3-264.0ppm) and Ni concentrations (68.9-258.0ppm) and Co: Ni ratio (0.31-1.90), together with relatively small Sr/Ba ratio in ore-bearing pyrites (0.11-0.50), supports a hydrothermal origin of mineralization at Gaosongshan gold deposit. Compared with volcanic rocks, the chondrite-normalized REE patterns of ore-bearing pyrites and quartz are all LREE enriched with similar ΣLREE/ΣHREE ratio ranging from 7.37-13.68 in ore-bearing pyrites, 4.74-15.37 in ore-bearing quartz and no Ce anomalies. δEu values in ore-bearing pyrites and quartz are 0.65-1.66 (average=0.93) and 0.66-1.62 (average=1.03), respectively. δEu values of volcanic rocks are 0.861.07 (average 0.94), suggesting no obvious negative Eu anomalies. Similar REE characteristics of ore-bearing pyrites and quartz and volcanic rocks, together with previous oxygen and hydrogen isotope studies of quartz, suggest that the ore-forming fluids of the Gaosongshan gold deposit were mainly magmatic origin which was associated with andesitic magma and was partly mixed with atmospheric water. Comparing trace elements characteristics of ore-bearing pyrites with volcanic rocks, together with previous S isotopic studies, it is concluded that the ore-forming materials were derived from the surrounding rocks. Slight changes of Y/Ho (23.8027.28), Zr/Hf (35.4147.83), Nb/Ta (10.9618.52) in ore-bearing pyrites indicate that the ore-forming fluid system is relatively stable during the ore-forming process.

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Ages, trace elements and Hf-isotopic compositions of zircons from claystones around the Permian-Triassic boundary in the Zunyi Section, South China: Implications for nature and tectonic setting of the volcanism

Journal of Earth Science ◽

10.1007/s12583-015-0589-9 ◽

2015 ◽

Vol 26 (6) ◽

pp. 872-882 ◽

Cited By ~ 17

Author(s):

Qiuling Gao ◽

Zhong-Qiang Chen ◽

Ning Zhang ◽

William L. Griffin ◽

Wenchen Xia ◽

...

Keyword(s):

Trace Elements ◽

South China ◽

Tectonic Setting ◽

Triassic Boundary ◽

Isotopic Compositions ◽

Permian Triassic Boundary

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New seismological data from the Calabrian arc reveal arc-orthogonal extension across the subduction zone

Scientific Reports ◽

10.1038/s41598-020-79719-8 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Tiziana Sgroi ◽

Alina Polonia ◽

Graziella Barberi ◽

Andrea Billi ◽

Luca Gasperini

Keyword(s):

Lateral Displacement ◽

Tectonic Setting ◽

Plate Boundary ◽

Velocity Model ◽

Tectonic Deformation ◽

Accretionary Wedge ◽

Tectonic Structures ◽

Plate Convergence ◽

Seismogenic Layer ◽

Regional Tectonic

AbstractThe Calabrian Arc subduction-rollback system along the convergent Africa/Eurasia plate boundary is among the most active geological structures in the Mediterranean Sea. However, its seismogenic behaviour is largely unknown, mostly due to the lack of seismological observations. We studied low-to-moderate magnitude earthquakes recorded by the seismic network onshore, integrated by data from a seafloor observatory (NEMO-SN1), to compute a lithospheric velocity model for the western Ionian Sea, and relocate seismic events along major tectonic structures. Spatial changes in the depth distribution of earthquakes highlight a major lithospheric boundary constituted by the Ionian Fault, which separates two sectors where thickness of the seismogenic layer varies over 40 km. This regional tectonic boundary represents the eastern limit of a domain characterized by thinner lithosphere, arc-orthogonal extension, and transtensional tectonic deformation. Occurrence of a few thrust-type earthquakes in the accretionary wedge may suggest a locked subduction interface in a complex tectonic setting, which involves the interplay between arc-orthogonal extension and plate convergence. We finally note that distribution of earthquakes and associated extensional deformation in the Messina Straits region could be explained by right-lateral displacement along the Ionian Fault. This observation could shed new light on proposed mechanisms for the 1908 Messina earthquake.

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