Pub Date : 2024-07-18DOI: 10.1134/s1075701524700053
A. V. Grigorieva, A. V. Lalomov, V. A. Zaitsev, D. A. Lalomov, A. V. Chefranova
Abstract
Loparite is the main placer-forming mineral in placers located along the periphery of the Lovozero alkaline massif. The article presents new materials of the study of loparite from samples taken during field work at the Sergevan site of the Revda placer, located near the northern frame of the massif. The mineral was extracted from the heavy fraction of a technological sample weighing about 30 kg. The paper presents the results of a study of the morphology, features of the chemical composition and internal structure of loparite from placers, as well as its relationship with the bedrock of the massif. Two loparite grains groups were determined: loparite-1, represented by large (0.25–0.75 mm) twins of crystals of regular crystallographic forms, and loparite-2, comprises smaller (0.05–0.20 mm) fragments of irregular shape. The work studied the mineralogical features of each type of grains and revealed their relationship with the bedrock mineralization. The study of the typomorphic features of placer loparite makes it possible to develop an optimal technological scheme for the enrichment of placers to expand the rare metal resource base of Russia
{"title":"Loparite in Placers of the Lovozero Placer Cluster Using the Example of the Sergevan Site","authors":"A. V. Grigorieva, A. V. Lalomov, V. A. Zaitsev, D. A. Lalomov, A. V. Chefranova","doi":"10.1134/s1075701524700053","DOIUrl":"https://doi.org/10.1134/s1075701524700053","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Loparite is the main placer-forming mineral in placers located along the periphery of the Lovozero alkaline massif. The article presents new materials of the study of loparite from samples taken during field work at the Sergevan site of the Revda placer, located near the northern frame of the massif. The mineral was extracted from the heavy fraction of a technological sample weighing about 30 kg. The paper presents the results of a study of the morphology, features of the chemical composition and internal structure of loparite from placers, as well as its relationship with the bedrock of the massif. Two loparite grains groups were determined: loparite-1, represented by large (0.25–0.75 mm) twins of crystals of regular crystallographic forms, and loparite-2, comprises smaller (0.05–0.20 mm) fragments of irregular shape. The work studied the mineralogical features of each type of grains and revealed their relationship with the bedrock mineralization. The study of the typomorphic features of placer loparite makes it possible to develop an optimal technological scheme for the enrichment of placers to expand the rare metal resource base of Russia</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"140 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141745842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-18DOI: 10.1134/s1075701524600099
A. V. Chugaev, E. Yu. Anikina, N. S. Bortnikov, V. V. Aristov, A. V. Travin, D. B. Bondar, I. V. Rassokhin, T. I. Oleynikova
Abstract
The large Zun-Kholba deposit, relating to a numerous group of orogenic-type gold deposits, is in the Eastern Sayan (Russia)—a segment of the Altai-Sayan fold system of the Central Asian Orogenic Belt. The paper discusses the results of mineralogical, geochemical, geochronological, and Pb-isotopic studies of gold mineralization; the purpose was to verify the genetic model of the deposit. Mineralogical and geochemical data obtained for ore bodies located between hypsometric levels from 1290 to 2090 m indicate a complex distribution of mineral associations at the deposit. There is no vertical and horizontal zonation in the distribution of mineral associations, in the chemical composition of the main ore minerals, as well as in the content of impurity elements in them. In dating ore-forming processes at the Zun-Kholba deposit, a comprehensive approach based on the study of K–Ar and Rb–Sr isotope systems of metasomatites was applied. The combination of Rb–Sr and 40Ar–39Ar methods allowed us to determine that the age of gold mineralization is 411 ± 2 Ma, while the age of the superimposed event, which is associated with redistribution of ore, as well as disturbance of the Rb–Sr and K–Ar isotopic systems of metasomatites, is about 380 Ma. Pb–Pb isotopic study of ore mineralization at the deposit and host Precambrian rocks allowed to prove the leading contribution of the latter in ore lead supply to the mineral-forming system. The model of formation of the Zun-Kholba orogenic gold deposit assumes a genetic relationship between ore-forming processes and intraplate alkaline mafic magmatism due to the impact of the plume in the Early Devonian time on the lithosphere of the Tuva-Mongolian terrane.
{"title":"A Mantle–Plume Model for the Formation of the Zun-Kholba Orogenic Gold Deposit (Eastern Sayan, Russia): Mineralogical Results, Rb–Sr and 40Ar–39Ar Geochronological and Pb–Pb Isotope Studies","authors":"A. V. Chugaev, E. Yu. Anikina, N. S. Bortnikov, V. V. Aristov, A. V. Travin, D. B. Bondar, I. V. Rassokhin, T. I. Oleynikova","doi":"10.1134/s1075701524600099","DOIUrl":"https://doi.org/10.1134/s1075701524600099","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The large Zun-Kholba deposit, relating to a numerous group of orogenic-type gold deposits, is in the Eastern Sayan (Russia)—a segment of the Altai-Sayan fold system of the Central Asian Orogenic Belt. The paper discusses the results of mineralogical, geochemical, geochronological, and Pb-isotopic studies of gold mineralization; the purpose was to verify the genetic model of the deposit. Mineralogical and geochemical data obtained for ore bodies located between hypsometric levels from 1290 to 2090 m indicate a complex distribution of mineral associations at the deposit. There is no vertical and horizontal zonation in the distribution of mineral associations, in the chemical composition of the main ore minerals, as well as in the content of impurity elements in them. In dating ore-forming processes at the Zun-Kholba deposit, a comprehensive approach based on the study of K–Ar and Rb–Sr isotope systems of metasomatites was applied. The combination of Rb–Sr and <sup>40</sup>Ar–<sup>39</sup>Ar methods allowed us to determine that the age of gold mineralization is 411 ± 2 Ma, while the age of the superimposed event, which is associated with redistribution of ore, as well as disturbance of the Rb–Sr and K–Ar isotopic systems of metasomatites, is about 380 Ma. Pb–Pb isotopic study of ore mineralization at the deposit and host Precambrian rocks allowed to prove the leading contribution of the latter in ore lead supply to the mineral-forming system. The model of formation of the Zun-Kholba orogenic gold deposit assumes a genetic relationship between ore-forming processes and intraplate alkaline mafic magmatism due to the impact of the plume in the Early Devonian time on the lithosphere of the Tuva-Mongolian terrane.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"80 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141738108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1134/s1075701524010069
T. V. Svetlitskaya, P. A. Nevolko
Abstract
The Zhireken Mo-porphyry deposit is located within the West Stanovoi terrane of the Transbaikalia sector of the Mongol–Okhotsk orogenic belt and is linked to the Middle–Late Jurassic Zhireken composite intrusion. Despite the long-term history of exploration of the deposit, many issues regarding magmatism and ore mineralization remain undetermined. In particular, the ore-producing granitoid intrusion that is genetically related to the deposit formation has not yet been identified. The study provides new U–Pb LA-ICP-MS zircon ages and geochemical whole-rock and zircon compositions obtained for igneous rocks of the Zhireken deposit. The research shows that the deposit is spatially associated with a series of high-K calc-alkaline to shoshonitic I-type granitoid intrusions that were emplaced at around 158–166 Ma at the postcollision stage of the evolution of the Mongol–Okhotsk Ocean. The sequence of the intrusive events includes biotite leucogranite (U–Pb age of ca. 164–166 Ma) → biotite–amphibole granite and granodiorite (U–Pb age of ca. 161–163 Ma) → dikes of granite-porphyry (U–Pb age of ca. 162–163 Ma), leucogranite-porphyry, and (quartz) diorite-porphyry → dikes of quartz monzonite-porphyry (U–Pb age of ca. 158 Ma). The U–Pb dates obtained and the observed geological relationships between granitoids and ore mineralization suggest that the emplacement of an ore-causative granite intrusion and the formation of porphyry-Mo stockwork system at the Zhireken deposit occurred in the interval of a. 158–161 Ma. A thorough examination employing geochemical whole-rock and mineral (zircon) fertility indicators reveals no genetic link between the studied granitoids and porphyry mineralization since they are all generated from weakly oxidized magmas. The ore-causative granitoid intrusion genetically related to Mo mineralization at the Zhireken deposit is either buried or represented by a rock type that is out of focus in both the present and previous studies.
{"title":"U–Pb Ages and Whole-Rock and Zircon Geochemistry of Granitoids from the Zhireken Mo-Porphyry Deposit, Eastern Transbaikalia: New Insights into the Link to Mineralization","authors":"T. V. Svetlitskaya, P. A. Nevolko","doi":"10.1134/s1075701524010069","DOIUrl":"https://doi.org/10.1134/s1075701524010069","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Zhireken Mo-porphyry deposit is located within the West Stanovoi terrane of the Transbaikalia sector of the Mongol–Okhotsk orogenic belt and is linked to the Middle–Late Jurassic Zhireken composite intrusion. Despite the long-term history of exploration of the deposit, many issues regarding magmatism and ore mineralization remain undetermined. In particular, the ore-producing granitoid intrusion that is genetically related to the deposit formation has not yet been identified. The study provides new U–Pb LA-ICP-MS zircon ages and geochemical whole-rock and zircon compositions obtained for igneous rocks of the Zhireken deposit. The research shows that the deposit is spatially associated with a series of high-K calc-alkaline to shoshonitic I-type granitoid intrusions that were emplaced at around 158–166 Ma at the postcollision stage of the evolution of the Mongol–Okhotsk Ocean. The sequence of the intrusive events includes biotite leucogranite (U–Pb age of ca. 164–166 Ma) → biotite–amphibole granite and granodiorite (U–Pb age of ca. 161–163 Ma) → dikes of granite-porphyry (U–Pb age of ca. 162–163 Ma), leucogranite-porphyry, and (quartz) diorite-porphyry → dikes of quartz monzonite-porphyry (U–Pb age of ca. 158 Ma). The U–Pb dates obtained and the observed geological relationships between granitoids and ore mineralization suggest that the emplacement of an ore-causative granite intrusion and the formation of porphyry-Mo stockwork system at the Zhireken deposit occurred in the interval of a. 158–161 Ma. A thorough examination employing geochemical whole-rock and mineral (zircon) fertility indicators reveals no genetic link between the studied granitoids and porphyry mineralization since they are all generated from weakly oxidized magmas. The ore-causative granitoid intrusion genetically related to Mo mineralization at the Zhireken deposit is either buried or represented by a rock type that is out of focus in both the present and previous studies.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"251 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615890","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1134/s1075701524010021
A. N. Berzina, A. P. Berzina, V. O. Gimon
Abstract
The Sorskoe (Sorsk, Sora) porphyry Cu–Mo deposit is located in the Kuznetsk Alatau, in the northwest of the Altai-Sayan folded region. Commercial Cu–Mo mineralization is closely associated with small porphyry intrusions (stocks, dikes) localized in the Uibat pluton. The magmatites of the pluton and small intrusions are composed of rocks of the gabbroid, monzonitoid, and granite/leucogranite associations. The rock associations of the pluton and small porphyry intrusions are similar in mineral composition, type of metallogenic specialization, petrogeochemical and isotopiс characteristics. The gabbroic and monzonitic rocks were probably generated by fractionation of the mafic magma and assimilation of lower crustal material. The geochemical characteristics indicate the absence of a genetic relationship between basic/intermediate rocks and the granite/leucogranite association. The rocks of the granite/leucogranite association were probably derived from the silicic magma generated by partial melting of the juvenile lower mafic crust due to the heat released from the mafic magma. U-Pb geochronological data indicate a time gap between the completion of pluton formation (∼478 Ma) and emplacement of small porphyry intrusions (from ∼467 to ∼457 Ma). Age differences between pluton and small intrusions suggest they are not coeval and were probably sourced from independent upper-middle crust magma chambers, which were formed by ascending melts derived from a deep large long-lived magma reservoir. The rocks of the Uibat pluton represent the remnant of the earlier solidified and eroded magma chamber. Periodic episodes of magma supply from a late shallow magma chamber resulted in the formation of small porphyry intrusions. Together these observations suggest that the magmatites of the pluton and small intrusions are not comagmatic. Their magmas may have been derived from a common deep-seated source, but possibly evolved independently, that is, they do not represent a single magma lineage, as often noted for porphyry Cu–Mo deposits. Changing tectonic environment before the emplacement of small intrusions triggered porphyry magma ascent, fluid saturation and exsolution and provided favorable conditions for large-scale mineralization.
{"title":"Age and Relationship between Magmatites of a Pluton and Small Intrusions (Sorskoe Porphyry Cu–Mo Deposit, Khakassia)","authors":"A. N. Berzina, A. P. Berzina, V. O. Gimon","doi":"10.1134/s1075701524010021","DOIUrl":"https://doi.org/10.1134/s1075701524010021","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Sorskoe (Sorsk, Sora) porphyry Cu–Mo deposit is located in the Kuznetsk Alatau, in the northwest of the Altai-Sayan folded region. Commercial Cu–Mo mineralization is closely associated with small porphyry intrusions (stocks, dikes) localized in the Uibat pluton. The magmatites of the pluton and small intrusions are composed of rocks of the gabbroid, monzonitoid, and granite/leucogranite associations. The rock associations of the pluton and small porphyry intrusions are similar in mineral composition, type of metallogenic specialization, petrogeochemical and isotopiс characteristics. The gabbroic and monzonitic rocks were probably generated by fractionation of the mafic magma and assimilation of lower crustal material. The geochemical characteristics indicate the absence of a genetic relationship between basic/intermediate rocks and the granite/leucogranite association. The rocks of the granite/leucogranite association were probably derived from the silicic magma generated by partial melting of the juvenile lower mafic crust due to the heat released from the mafic magma. U-Pb geochronological data indicate a time gap between the completion of pluton formation (∼478 Ma) and emplacement of small porphyry intrusions (from ∼467 to ∼457 Ma). Age differences between pluton and small intrusions suggest they are not coeval and were probably sourced from independent upper-middle crust magma chambers, which were formed by ascending melts derived from a deep large long-lived magma reservoir. The rocks of the Uibat pluton represent the remnant of the earlier solidified and eroded magma chamber. Periodic episodes of magma supply from a late shallow magma chamber resulted in the formation of small porphyry intrusions. Together these observations suggest that the magmatites of the pluton and small intrusions are not comagmatic. Their magmas may have been derived from a common deep-seated source, but possibly evolved independently, that is, they do not represent a single magma lineage, as often noted for porphyry Cu–Mo deposits. Changing tectonic environment before the emplacement of small intrusions triggered porphyry magma ascent, fluid saturation and exsolution and provided favorable conditions for large-scale mineralization.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"30 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140616030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1134/s1075701524010070
V. S. Vesnin, P. A. Nevolko, T. V. Svetlitskaya, P. A. Fominykh, D. V. Bondarchuk
Abstract
The Bystrinsky Cu–Au–Fe porphyry–skarn and Shakhtama Mo-porphyry deposits are located in Eastern Transbaikalia, Russia. The host rocks in the deposits are multiphase granitoid plutons of the Middle–Late Jurassic Shakhtama complex. Economical mineralization is genetically related to small bodies of granite porphyries and granodiorite porphyries of late phases. To identify the specifics of fertile magmatic rocks, the composition of volatile components and rare-earth elements in apatite from fertile and barren intrusions was studied. Special attention was paid to the proof of the primary magmatic origin of apatite and the absence of influence of metasomatic alteration processes on their composition. It was shown that fertile intrusions at the Bystrinsky and Shakhtama deposits are characterized by an increased SO3 content in apatite, which indicates their formation from oxidized melts. In addition, it is shown that the presence of sulfate sulfur in the melt is a necessary for the sulfide ore formation. It has been established that a high Cl content (>0.8 wt %) in fertile magmatic rocks, which ensures the transfer of chalcophilic elements, is a characteristic difference between apatites from Cu-porphyry and Mo-porphyry systems. The content of volatile apatite can be used as a sign of fertility for porphyry systems. An analysis of the trace element composition of apatite made it possible to establish that apatites from fertile granitoids of the Shakhtama and Bystrinsky deposits are characterized by Eu/Eu* > 0.4, which indicates the oxidation and high water saturation of the parental melts. The revealed characteristics of apatite from fertile intrusions and their discreteness from barren granitoids can serve as a sign of fertility of igneous rocks for porphyry mineralization.
{"title":"Apatite Geochemistry As a Fertility Tool for Porphyry Systems (Using the Example of the Shakhtama Mo-Porphyry and Bystrinsky Cu–Au–Fe-Porphyry–Skarn Deposits, Eastern Transbaikalia, Russia)","authors":"V. S. Vesnin, P. A. Nevolko, T. V. Svetlitskaya, P. A. Fominykh, D. V. Bondarchuk","doi":"10.1134/s1075701524010070","DOIUrl":"https://doi.org/10.1134/s1075701524010070","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Bystrinsky Cu–Au–Fe porphyry–skarn and Shakhtama Mo-porphyry deposits are located in Eastern Transbaikalia, Russia. The host rocks in the deposits are multiphase granitoid plutons of the Middle–Late Jurassic Shakhtama complex. Economical mineralization is genetically related to small bodies of granite porphyries and granodiorite porphyries of late phases. To identify the specifics of fertile magmatic rocks, the composition of volatile components and rare-earth elements in apatite from fertile and barren intrusions was studied. Special attention was paid to the proof of the primary magmatic origin of apatite and the absence of influence of metasomatic alteration processes on their composition. It was shown that fertile intrusions at the Bystrinsky and Shakhtama deposits are characterized by an increased SO<sub>3</sub> content in apatite, which indicates their formation from oxidized melts. In addition, it is shown that the presence of sulfate sulfur in the melt is a necessary for the sulfide ore formation. It has been established that a high Cl content (>0.8 wt %) in fertile magmatic rocks, which ensures the transfer of chalcophilic elements, is a characteristic difference between apatites from Cu-porphyry and Mo-porphyry systems. The content of volatile apatite can be used as a sign of fertility for porphyry systems. An analysis of the trace element composition of apatite made it possible to establish that apatites from fertile granitoids of the Shakhtama and Bystrinsky deposits are characterized by Eu/Eu* > 0.4, which indicates the oxidation and high water saturation of the parental melts. The revealed characteristics of apatite from fertile intrusions and their discreteness from barren granitoids can serve as a sign of fertility of igneous rocks for porphyry mineralization.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"36 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1134/s1075701524010033
A. F. Chitalin, I. A. Baksheev, Yu. N. Nikolaev
Abstract
The results of modern studies of the Baimka Ore Zone (BOZ) in Western Chukotka obtained during prospecting and exploration in 2008–2016 are summarized, and the main features of its structure and development are shown. The porphyry–epithermal ore systems of the BOZ were formed within the NW-trending regional-scale dextral strike-slip fault in the Early Cretaceous time. Meridional extensional structures and diagonal strike-slip faults in the strike-strip fault zone controlled the position and morphology of intrusive bodies of monzonites and paragenetically related with them ore stockworks with porphyry copper and gold–silver epithermal mineralization. Ore stockworks were traced to 700-m depth by drilling, and, accordingly to the geophysical data, mineralization is forecasting deeper. The zoning of soil anomalies and the primary geochemical zoning of the Peschanka deposit and the Nakhodka ore field are described. An erosion levels of deposits are different. For the Peschanka deposit, an upper-middle erosion level has been established. For the deposits of the Nakhodka Ore Field, the erosion grade changes from the upper to the lower level. New prospects have been identified within the BOZ, where economical porphyry copper and gold–silver epithermal mineralization is predicted.
{"title":"Porphyry Copper and Epithermal Gold–Silver Mineralization of the Baimka Ore Zone, Western Chukotka, Russia","authors":"A. F. Chitalin, I. A. Baksheev, Yu. N. Nikolaev","doi":"10.1134/s1075701524010033","DOIUrl":"https://doi.org/10.1134/s1075701524010033","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The results of modern studies of the Baimka Ore Zone (BOZ) in Western Chukotka obtained during prospecting and exploration in 2008–2016 are summarized, and the main features of its structure and development are shown. The porphyry–epithermal ore systems of the BOZ were formed within the NW-trending regional-scale dextral strike-slip fault in the Early Cretaceous time. Meridional extensional structures and diagonal strike-slip faults in the strike-strip fault zone controlled the position and morphology of intrusive bodies of monzonites and paragenetically related with them ore stockworks with porphyry copper and gold–silver epithermal mineralization. Ore stockworks were traced to 700-m depth by drilling, and, accordingly to the geophysical data, mineralization is forecasting deeper. The zoning of soil anomalies and the primary geochemical zoning of the Peschanka deposit and the Nakhodka ore field are described. An erosion levels of deposits are different. For the Peschanka deposit, an upper-middle erosion level has been established. For the deposits of the Nakhodka Ore Field, the erosion grade changes from the upper to the lower level. New prospects have been identified within the BOZ, where economical porphyry copper and gold–silver epithermal mineralization is predicted.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"36 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140616038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1134/s1075701524010094
A. S. Yakubchuk
Abstract
Higher gold grades (0.1–1 g/t) in porphyry systems of northern Eurasia make them competitive with the Andean porphyries despite usually smaller volumes of mineralization and lower copper grades. It is concluded that porphyry systems of northern Eurasia occurred in island arc settings as did the porphyries of the West Pacific, contrary to the Andean continental magmatic arcs. The paper considers structural and tectonic control of porphyry clusters in northern Eurasia, as well as practical aspects to estimate the depth of erosion in porphyry systems.
{"title":"Porphyry Deposits of Northern Eurasia: Practical Aspects of Tectonic Control, Structural Features and Estimates of Depth of Erosion from the Urals to the Pacific","authors":"A. S. Yakubchuk","doi":"10.1134/s1075701524010094","DOIUrl":"https://doi.org/10.1134/s1075701524010094","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Higher gold grades (0.1–1 g/t) in porphyry systems of northern Eurasia make them competitive with the Andean porphyries despite usually smaller volumes of mineralization and lower copper grades. It is concluded that porphyry systems of northern Eurasia occurred in island arc settings as did the porphyries of the West Pacific, contrary to the Andean continental magmatic arcs. The paper considers structural and tectonic control of porphyry clusters in northern Eurasia, as well as practical aspects to estimate the depth of erosion in porphyry systems.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"97 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615896","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1134/s1075701524010057
K. O. Shishkanova, V. M. Okrugin, T. M. Filosofova
Abstract
The Mutnovskoe deposit is one of the largest and most prospective ore deposits in South Kamchatka. The northern and southern flanks within the main veining zone Opredelyayushchaya, composed of low-sulfi (goldsilver) and sulfide-polymetallic (gold-silver-polymetallic) types of ores, respectively, are distinguished. The paper presents the results of the complex mineralogical and geochemical studies of the gold-silver-polymetallic ores of the southern flank of the deposit. Features of textures and structures, mineral, chemical compositions and genesis of the ores, as well forms of precious and base metals occurrences are shown. Typomorphic features of pyrite, sphalerite, galena, chalcopyrite, tennantite-tetrahedrite, Au, Ag, Pb and Bi tellurides, native gold, Bi, Se and Ag sulfosalts are characterized. The pyrite-sphalerite, quartz, sphalerite-galena-quartz, and chalcopyrite-tennantite-tetrahedrite mineral associations are distinguished. The temperatures and composition of ore-forming solutions are shown.
{"title":"Features of the Mineralogy of the Ores of the Southern Flank of the Mutnovskoe Gold–Silver–Polymetallic Deposit (Southern Kamchatka)","authors":"K. O. Shishkanova, V. M. Okrugin, T. M. Filosofova","doi":"10.1134/s1075701524010057","DOIUrl":"https://doi.org/10.1134/s1075701524010057","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The Mutnovskoe deposit is one of the largest and most prospective ore deposits in South Kamchatka. The northern and southern flanks within the main veining zone Opredelyayushchaya, composed of low-sulfi (goldsilver) and sulfide-polymetallic (gold-silver-polymetallic) types of ores, respectively, are distinguished. The paper presents the results of the complex mineralogical and geochemical studies of the gold-silver-polymetallic ores of the southern flank of the deposit. Features of textures and structures, mineral, chemical compositions and genesis of the ores, as well forms of precious and base metals occurrences are shown. Typomorphic features of pyrite, sphalerite, galena, chalcopyrite, tennantite-tetrahedrite, Au, Ag, Pb and Bi tellurides, native gold, Bi, Se and Ag sulfosalts are characterized. The pyrite-sphalerite, quartz, sphalerite-galena-quartz, and chalcopyrite-tennantite-tetrahedrite mineral associations are distinguished. The temperatures and composition of ore-forming solutions are shown.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"36 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140616031","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.1134/s1075701524010045
N. V. Shatova, A. V. Molchanov, A. V. Terekhov, V. V. Shatov, O. V. Petrov, S. A. Sergeev, E. M. Prasolov, G. P. Dvornik, V. I. Leontev
Abstract
In the territory of the Ryabinovoe porphyry copper-gold deposit, ore mineralization is confined to multi-stage metasomatism fields, which were formed in two stages. At the first, pre-ore stage, high-temperature potassium-sodium metasomatites (aegirine feldspathites) were formed, at the second stage, medium-low-temperature wallrock gumbeites in the form of two facies varieties: carbonate-sericite-muscovite-orthoclase and quartz-carbonate-barite-adular varieties. Results of isotope studies (U-Pb, Rb-Sr, Re-Os, 40Ar/36Ar, 3He/4He, 20Ne) of the aforementioned metasomatites and ore mineralization are discussed in the paper.
{"title":"The Ryabinovoe Porphyry Cu–Au Deposit (Southern Yakutia): Geology, Wallrock Alteration, Noble Gases Isotope Systematics and Isotopic Dating of Mineralization Processes","authors":"N. V. Shatova, A. V. Molchanov, A. V. Terekhov, V. V. Shatov, O. V. Petrov, S. A. Sergeev, E. M. Prasolov, G. P. Dvornik, V. I. Leontev","doi":"10.1134/s1075701524010045","DOIUrl":"https://doi.org/10.1134/s1075701524010045","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>In the territory of the Ryabinovoe porphyry copper-gold deposit, ore mineralization is confined to multi-stage metasomatism fields, which were formed in two stages. At the first, pre-ore stage, high-temperature potassium-sodium metasomatites (<i>aegirine feldspathites</i>) were formed, at the second stage, medium-low-temperature wallrock <i>gumbeites</i> in the form of two facies varieties: <i>carbonate-sericite-muscovite-orthoclase</i> and <i>quartz-carbonate-barite-adular</i> varieties. Results of isotope studies (U-Pb, Rb-Sr, Re-Os, <sup>40</sup>Ar/<sup>36</sup>Ar, <sup>3</sup>He/<sup>4</sup>He, <sup>20</sup>Ne) of the aforementioned metasomatites and ore mineralization are discussed in the paper.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"26 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140615897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-06DOI: 10.1134/s1075701523070176
N. S. Bortnikov, N. D. Tolstykh
Abstract
The results of studying the epithermal deposits of Kamchatka, one of the most promising gold-mining provinces of the Russian Federation, are generalized. The deposits are divided into acid–sulfate (Ac-Sul) and adularia–sericite (Ad-Ser) types (Heald et al., 1987). The disadvantages of the scheme, which is the most popular in the English-language literature and is based on the sulfidation state of mineral parageneses in ores (LS, IS, and HS types), are shown. The classification that we proposed includes differences in mineral associations in circum–ore metasomatites, which are determined by the acidity–alkalinity and an oxidation state of mineral-forming fluids, and are clearly diagnosed at the first stages of studying the deposits. Kamchatka epithermal deposits of the Ad-Ser-type are associated with andesite volcanism of the volcanic belts. Gold ore associations are concentrated in quartz, carbonate–quartz, and adularia–quartz veins, as well as in sericitized metasomatites, which are replaced by argillizites and propylites towards the periphery. The Ad-Ser-type is characterized by combination with polysulfide (Pb, Zn) (Amethyst, Kumroch, Vilyuchinskoe deposits), sulfosalt (Ag, Sb, As, Bi, Sn) (Ozernovskoe, Baranyevskoe), and selenide (Ag, Se) (Amethyst, Asachinskoe, Rodnikovoe) assemblages. Low-fineness native gold (220–310‰) is typical of the early polysulfide assemblage. With an increase in the fugacity of Te and Se, the gold fineness increases to 510–740‰, and with the progressive activity of Sb, As and Bi and the formation of sulfosalt associations, it reaches 998‰. The homogenization temperatures of primary fluid inclusions in quartz from gold-bearing associations of the Ad-Ser-type are 260–250°C; the minerals crystallize from solutions containing no more than 3 wt % NaCl eq. Maletoyvayam, the only Ac-Sul-type deposit in Kamchatka, is localized in quartz, secondary quartzites, and alunite–sericite–kaolinite–quartz metasomatites. Gold-bearing parageneses indicate the leading role of selenium in mineral formation, contain high-fineness native gold, sulfoselenotellurides, tellurides, and selenides of Au, which crystallize from acidic fluids with salinity of 1–5 wt % NaCl eq. at temperatures of 290–175°C.
{"title":"Epithermal Deposits of Kamchatka, Russia","authors":"N. S. Bortnikov, N. D. Tolstykh","doi":"10.1134/s1075701523070176","DOIUrl":"https://doi.org/10.1134/s1075701523070176","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The results of studying the epithermal deposits of Kamchatka, one of the most promising gold-mining provinces of the Russian Federation, are generalized. The deposits are divided into acid–sulfate (Ac-Sul) and adularia–sericite (Ad-Ser) types (Heald et al., 1987). The disadvantages of the scheme, which is the most popular in the English-language literature and is based on the sulfidation state of mineral parageneses in ores (LS, IS, and HS types), are shown. The classification that we proposed includes differences in mineral associations in circum–ore metasomatites, which are determined by the acidity–alkalinity and an oxidation state of mineral-forming fluids, and are clearly diagnosed at the first stages of studying the deposits. Kamchatka epithermal deposits of the Ad-Ser-type are associated with andesite volcanism of the volcanic belts. Gold ore associations are concentrated in quartz, carbonate–quartz, and adularia–quartz veins, as well as in sericitized metasomatites, which are replaced by argillizites and propylites towards the periphery. The Ad-Ser-type is characterized by combination with polysulfide (Pb, Zn) (Amethyst, Kumroch, Vilyuchinskoe deposits), sulfosalt (Ag, Sb, As, Bi, Sn) (Ozernovskoe, Baranyevskoe), and selenide (Ag, Se) (Amethyst, Asachinskoe, Rodnikovoe) assemblages. Low-fineness native gold (220–310‰) is typical of the early polysulfide assemblage. With an increase in the fugacity of Te and Se, the gold fineness increases to 510–740‰, and with the progressive activity of Sb, As and Bi and the formation of sulfosalt associations, it reaches 998‰. The homogenization temperatures of primary fluid inclusions in quartz from gold-bearing associations of the Ad-Ser-type are 260–250°C; the minerals crystallize from solutions containing no more than 3 wt % NaCl eq. Maletoyvayam, the only Ac-Sul-type deposit in Kamchatka, is localized in quartz, secondary quartzites, and alunite–sericite–kaolinite–quartz metasomatites. Gold-bearing parageneses indicate the leading role of selenium in mineral formation, contain high-fineness native gold, sulfoselenotellurides, tellurides, and selenides of Au, which crystallize from acidic fluids with salinity of 1–5 wt % NaCl eq. at temperatures of 290–175°C.</p>","PeriodicalId":12719,"journal":{"name":"Geology of Ore Deposits","volume":"2012 1","pages":""},"PeriodicalIF":0.7,"publicationDate":"2024-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140881392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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