Porphyry Cu-Au±Mo mineralization hosted by potassic igneous rocks: implications from the giant Peschanka porphyry deposit, Baimka Trend (North East Siberia, Russia)

2021 ◽  
pp. SP513-2020-178
Author(s):  
Andrey F. Chitalin ◽  
Ivan A. Baksheev ◽  
Yurii N. Nikolaev ◽  
Georgy T. Djedjeya ◽  
Yuliya N. Khabibullina ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Igneous Rocks ◽  
Oxidation States ◽  
Island Arcs ◽  
Porphyry Cu ◽  
North East ◽  
Average Grade ◽  
High K ◽  
High Oxidation ◽  
Other World

AbstractPorphyry Cu-Au±Mo mineralization at Peschanka is hosted by monzodiorite and monzonite intrusions with high-K calc-alkaline to shoshonitic compositions and dated at about 144.1±1.5 Ma, using U/Pb zircon ages. The Cretaceous intrusions are emplaced in a melange of Cretaceous island arcs, a tectonic setting comparable to other world-class porphyry Cu-Au deposits, such as Oyu Tolgoi, Mongolia, and Pebble, Alaska.Abundant primary magnetite contents of the Peschanka intrusions, as well as numerous gypsum and anhydrite veins, reflect the high oxidation states of their parental magmas. This mineralogical interpretation is confirmed by high whole-rock Fe2O3/FeO ratios and high V/Sc ratios of the rocks of up to 1.27 and up to 21.9, respectively. The whole-rock Eu/Eu& ratios of the Peschanka intrusions are ≥1 which is also typical for potassic igneous rocks with high oxidation states. Abundant amphibole and biotite phenocrysts of the intrusions as well as their high whole-rock Sr/Y ratios of up to 225 document significantly high H2O contents of the high-K magmas.Peschanka contains a resource of >9.5 Mt of copper at an average grade of 0.43 wt% and 16.5 Moz of gold at a high average grade of 0.23 g/t and, thus, representing one of the largest undeveloped greenfield copper projects worldwide. The vicinity of Peschanka still offers significant brownfields exploration potential.The hypogene vein-related and disseminated Cu-Au±Mo sulfide mineralization at Peschanka is structurally-controlled by significant NE-trending strike-slips that acted as the conduits for the hydrothermal fluids. The central part of the orebody consists of high-grade N-S trending sheeted quartz-bornite veining with unusually high vein densities. The highest Cu and Au grades are directly correlated with high vein densities.Peschanka is defined by distinct hydrothermal alteration zones including potassic, phyllic, propylitic and argillic assemblages, but a distinct lack of advanced argillic alteration. The mineralization itself is also zoned ranging from a central Mo-Cpy-Bn sulfide assemblage to a peripheral Py-Mt-dominated zone (“pyrite-shell”). Late-stage polymetallic assemblages overprint and surround the main stockwork zone.

scholarly journals Tectonic Evolution of the West Bogeda: Evidences from Zircon U-Pb Geochronology and Geochemistry Proxies, NW China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 341
Author(s):  
Yalong Li ◽  
Wei Yue ◽  
Xun Yu ◽  
Xiangtong Huang ◽  
Zongquan Yao ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Tectonic Setting ◽  
Continental Rift ◽  
Middle Permian ◽  
Upper Permian ◽  
Late Permian ◽  
Island Arcs ◽  
The West ◽  
Structural Deformations ◽  
Tian Shan

The Bogeda Shan (Mountain) is in southern part of the Central Asian Orogenic Belt (CAOB) and well preserved Paleozoic stratigraphy, making it an ideal region to study the tectonic evolution of the CAOB. However, there is a long-standing debate on the tectonic setting and onset uplift of the Bogeda Shan. In this study, we report detrital zircon U-Pb geochronology and whole-rock geochemistry of the Permian sandstone samples, to decipher the provenance and tectonic evolution of the West Bogeda Shan. The Lower-Middle Permian sandstone is characterized by a dominant zircon peak age at 300–400 Ma, similar to the Carboniferous samples, suggesting their provenance inheritance and from North Tian Shan (NTS) and Yili-Central Tian Shan (YCTS). While the zircon record of the Upper Permian sandstone is characterized by two major age peaks at ca. 335 Ma and ca. 455 Ma, indicating the change of provenance after the Middle Permian and indicating the uplift of Bogeda Shan. The initial uplift of Bogeda Shan was also demonstrated by structural deformations and unconformity occurring at the end of Middle Permian. The bulk elemental geochemistry of sedimentary rocks in the West Bogeda Shan suggests the Lower-Middle Permian is mostly greywacke with mafic source dominance, and tectonic setting changed from the continental rift in the Early Permian to post rift in the Middle Permian. The Upper Permian mainly consists of litharenite and sublitharenite with mafic-intermediate provenances formed in continental island arcs. The combined evidences suggest the initial uplift of the Bogeda Shan occurred in the Late Permian, and three stages of mountain building include the continental rift, post-rift extensional depression, and continental arc from the Early, Middle, to Late Permian, respectively.

Geochemical, mineralogical, and isotopic data relating to the origin and tectonic setting of the Rossland volcanic rocks, southern British Columbia

1981 ◽  
Vol 18 (5) ◽  
pp. 858-868 ◽  
Author(s):  
B. Beddoe-Stephens ◽  
R. St J. Lambert
Keyword(s):  
British Columbia ◽  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Major And Trace Elements ◽  
Lower Jurassic ◽  
Island Arcs ◽  
Rock Types ◽  
Tectonic Environment ◽  
Isotopic Analyses ◽  
Arc Setting

Bulk-rock and mineral chemical and isotopic analyses of Rossland volcanic rocks are used to infer the nature of the magma extruded in the Nelson–Rossland area of southern British Columbia during the Early Jurassic. Metamorphism of the volcanic rocks to subgreenschist and greenschist facies precludes use of mobile major and trace elements (e.g., Na, K, and Rb) as petrogenetic indicators. Data on immobile elements (Ti, Zr, and Y) and pyroxene compositions indicate that the volcanic rocks formed in a destructive-margin plate tectonic environment. Present-day 87Sr/86Sr ratios range from 0.70372 to 0.70480 but do not define an isochron. Corrected to Jurassic time, the initial ratios range from 0.70328 to 0.70404. Whole-rock δO18 values range from 7.9 to 11.6%, correlating inversely with metamorphic grade. Clinopyroxene δO18 of 4.8–6.5 is comparable with fresh clinopyroxenes from mafic rocks of mantle origin. In view of the preponderance of basaltic rather than andesitic rock types, and because of the nature of the lithologies within the volcanic rocks and associated sediments, an island-arc setting is indicated. The appearance of primary amphibole in basaltic members of the Rossland suite, and the occurrence of ankaramitic rocks, are thought to indicate a mildly alkalic rather than a subalkalic parent magma. Comparison of the Rossland volcanic rocks with those of recent island arcs, and consideration of the Upper Triassic – Lower Jurassic paleogeography in the Cordillera, suggest the rocks may be related to a localized oceanic basin, their extrusion being associated with faults bounding its western edge.

scholarly journals Características Tectónicas de Áreas de Aporte para Arenas de Playas de Tierra del Fuego y Península Antártica, Argentina

2000 ◽  
Vol 27 (1) ◽  
pp. 69
Author(s):  
EDGARDO MARTÍN GELOS ◽  
JORGE OSVALDO SPAGNUOLO ◽  
FEDERICO IGNACIO ISLA
Keyword(s):  
Antarctic Peninsula ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Mineralogical Composition ◽  
Tierra Del Fuego ◽  
Heavy Minerals ◽  
Island Arcs ◽  
Sediment Sources ◽  
Pacific Margin ◽  
The Antarctic

Sand mineralogical analysis from 22 beaches were performed within the southernmost area of Argentina (Isla Grande de Tierra del Fuego), the Antarctic Peninsula and the Scotia Arc (South Orkney, South Shetland and James Ross islands included). Composition triangles of light and heavy minerals were considered in order to relate them to depocenters, sediment sources and tectonic setting. 71% of the sediments would have been transported from magmatic arcs, 24% from elevated crystalline basements and only 5% from recycled orogene. In regard to the heavy mineral distribution, 70% were assigned to a suite from an active continental margin and the remaining 30% would correspond to areas outside the continental margins (volcanic arcs). In a general way, sediment sources were related to active margins or volcanic island arcs. As an anomalous fact, it is stressed that the coasts of Tierra del Fuego and the western sector of the Antarctic Peninsula and adjacent islands, contain sediments from a Pacific margin but lying on a passive Atlantic margin. Finally, it should be adviced about the convenience to know the source areas when ice is the transport agent, as it avoids a selective ability and it does not modify the original mineralogical composition.

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