A new occurrence of the Mn-Ba ore mineral, romanechite, has been discovered in a small paleo-doline of the Apulian karst on Mesozoic carbonate rock successions, characterized by reddish incrustations and nodules made essentially by Fe-bearing calcite. The conditions under which Mn-Ba ore minerals form represent an intriguing area of research, as these minerals can act as scavengers for heavy elements, impacting soils, surface sediments, and even associated aquatic systems. The genesis of romanechite is linked to the progressive interaction of silicate aqueous solutions enriched in Al, Si, and Fe with the limestone substrate. The findings provide new insights into the genetic processes responsible for the formation of reddish Mn incrustations, supporting their polygenetic origin because of the chemical alteration of limestone and allochthonous siliciclastic muds.
{"title":"First Record of Romanechite in the Apulian Karst (Southern Italy) Resulting from the Interaction of Limestones and Clay Minerals","authors":"Annamaria Fornelli, Francesca Micheletti, Pasquale Acquafredda, Annarosa Mangone","doi":"10.3390/min14090935","DOIUrl":"https://doi.org/10.3390/min14090935","url":null,"abstract":"A new occurrence of the Mn-Ba ore mineral, romanechite, has been discovered in a small paleo-doline of the Apulian karst on Mesozoic carbonate rock successions, characterized by reddish incrustations and nodules made essentially by Fe-bearing calcite. The conditions under which Mn-Ba ore minerals form represent an intriguing area of research, as these minerals can act as scavengers for heavy elements, impacting soils, surface sediments, and even associated aquatic systems. The genesis of romanechite is linked to the progressive interaction of silicate aqueous solutions enriched in Al, Si, and Fe with the limestone substrate. The findings provide new insights into the genetic processes responsible for the formation of reddish Mn incrustations, supporting their polygenetic origin because of the chemical alteration of limestone and allochthonous siliciclastic muds.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"272 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215153","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}
Roman Shendrik, Nikita V. Chukanov, Alexander Bogdanov, Alexandra Myasnikova, Elizaveta Pankrushina, Anatoly A. Zolotarev, Anastasiia Babkina, Ekaterina Popova, Marina F. Vigasina, Sergey M. Aksenov, Grigoriy Ilyin, Igor V. Pekov
The article describes the results of a comprehensive study of the extra-framework components of scapolites using quantum–chemical calculations, electronic and vibrational spectroscopy, and single-crystal X-ray diffraction and crystal structure refinement. The ab initio calculations were performed using an embedded-cluster approach of extra-framework components in various cation surroundings. As a result, through comparing the experimental and ab initio calculation results, the energies of the electronic and vibrational transitions of various extra-framework components (CO3)2−, (CO3)·−, S3·−, S2·−—as well as the role of these components in the process of the lowering of the symmetry—were determined for scapolites belonging to the marialite–meionite solid–solution series. The nature of the various colors of the scapolites has also been established. Colors from purple to blue are a result of the presence of radiation-induced pairs of defects: carbonate radical anions (CO3)·− and F-centers. However, polysulfide S3·− radical anions are found in some violet scapolites.
文章介绍了利用量子化学计算、电子和振动光谱以及单晶 X 射线衍射和晶体结构细化对鳞片石框架外组分进行综合研究的结果。采用嵌入式簇方法对各种阳离子环境中的框架外组分进行了 ab initio 计算。结果，通过比较实验结果和 ab initio 计算结果，确定了属于万里石-梅安石固溶体系列的鳞片矿中各种框架外成分 (CO3)2-、(CO3)--、S3--、S2--的电子和振动跃迁能量，以及这些成分在降低对称性过程中的作用。此外，还确定了霞石各种颜色的性质。从紫色到蓝色的颜色是由于存在辐射诱导的成对缺陷：碳酸根阴离子 (CO3)-- 和 F-中心。不过，在一些紫色霞石中也发现了多硫化物 S3--基阴离子。
{"title":"Nature of Scapolite Color: Ab Initio Calculations, Spectroscopy, and Structural Study","authors":"Roman Shendrik, Nikita V. Chukanov, Alexander Bogdanov, Alexandra Myasnikova, Elizaveta Pankrushina, Anatoly A. Zolotarev, Anastasiia Babkina, Ekaterina Popova, Marina F. Vigasina, Sergey M. Aksenov, Grigoriy Ilyin, Igor V. Pekov","doi":"10.3390/min14090937","DOIUrl":"https://doi.org/10.3390/min14090937","url":null,"abstract":"The article describes the results of a comprehensive study of the extra-framework components of scapolites using quantum–chemical calculations, electronic and vibrational spectroscopy, and single-crystal X-ray diffraction and crystal structure refinement. The ab initio calculations were performed using an embedded-cluster approach of extra-framework components in various cation surroundings. As a result, through comparing the experimental and ab initio calculation results, the energies of the electronic and vibrational transitions of various extra-framework components (CO3)2−, (CO3)·−, S3·−, S2·−—as well as the role of these components in the process of the lowering of the symmetry—were determined for scapolites belonging to the marialite–meionite solid–solution series. The nature of the various colors of the scapolites has also been established. Colors from purple to blue are a result of the presence of radiation-induced pairs of defects: carbonate radical anions (CO3)·− and F-centers. However, polysulfide S3·− radical anions are found in some violet scapolites.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"560 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215155","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}
Jawad Ahmad, Rujun Chen, Ijaz Ahmed, Muhammad Yaseen, Shahid Ali Shah, Osama Abdul Rahim, Farid Ullah, Shah Fahad, Li Rui
The Qiushuwan Cu-Mo deposit, situated in the East Qinling molybdenum belt, is a notable mining site renowned for its considerable quantities of medium-sized molybdenum. The goal of this study is to improve comprehension and identify additional mineral resources by conducting a thorough examination of the mine using the spread spectrum-induced polarization (SSIP) technique. Gathering SSIP data, conducting geological investigations, and examining the electrical characteristics of rock and mineral samples along Profile-80 led to significant discoveries. The investigation identified two significant ore bodies with high conductivity: C2, linked to granite porphyry and molybdenum veins, and C4, associated with a skarn deposit containing a concentrated amount of copper ore. This study used resistivity models created from SSIP data to find out how conductivity changed in different parts of the research area. Additional drill verifications validated these findings, indicating the presence of potential mineral resources. The petrographic analysis of core samples showed that minerals like pyrite, molybdenite, chalcopyrite, epidote, calcite, and garnet were present. Notably, the samples frequently contained both pyrite and molybdenite together. Sample 04-2 contained substantial quantities of molybdenite and pyrite; Sample 05-1 had occasional pyrite; and Sample 07-4 included both pyrite and chalcopyrite. These findings offer useful insights for evaluating the magnitude and economic feasibility of the mineral deposits; however, additional investigation is required to completely comprehend the scope of the resources. The integration of borehole data and the alignment of geological sections with inversion models confirmed the validity of the conclusions. The core samples that were retrieved show a lot of different minerals, including valuable ores and minerals that have been changed. Pyrite and molybdenite are always found together. These findings establish a solid basis for further investigation and the sustainable management of resources. This study contributes to the understanding of the Qiushuwan Cu-Mo deposit and advances exploration techniques using the spread spectrum-induced polarization (SSIP) method. It provides useful information for geologists, mining professionals, and stakeholders involved in resource usage.
{"title":"Spread Spectrum Induced Polarization (SSIP) Survey for the Qiushuwan Copper–Molybdenum Deposits in Southern Henan Province, China","authors":"Jawad Ahmad, Rujun Chen, Ijaz Ahmed, Muhammad Yaseen, Shahid Ali Shah, Osama Abdul Rahim, Farid Ullah, Shah Fahad, Li Rui","doi":"10.3390/min14090934","DOIUrl":"https://doi.org/10.3390/min14090934","url":null,"abstract":"The Qiushuwan Cu-Mo deposit, situated in the East Qinling molybdenum belt, is a notable mining site renowned for its considerable quantities of medium-sized molybdenum. The goal of this study is to improve comprehension and identify additional mineral resources by conducting a thorough examination of the mine using the spread spectrum-induced polarization (SSIP) technique. Gathering SSIP data, conducting geological investigations, and examining the electrical characteristics of rock and mineral samples along Profile-80 led to significant discoveries. The investigation identified two significant ore bodies with high conductivity: C2, linked to granite porphyry and molybdenum veins, and C4, associated with a skarn deposit containing a concentrated amount of copper ore. This study used resistivity models created from SSIP data to find out how conductivity changed in different parts of the research area. Additional drill verifications validated these findings, indicating the presence of potential mineral resources. The petrographic analysis of core samples showed that minerals like pyrite, molybdenite, chalcopyrite, epidote, calcite, and garnet were present. Notably, the samples frequently contained both pyrite and molybdenite together. Sample 04-2 contained substantial quantities of molybdenite and pyrite; Sample 05-1 had occasional pyrite; and Sample 07-4 included both pyrite and chalcopyrite. These findings offer useful insights for evaluating the magnitude and economic feasibility of the mineral deposits; however, additional investigation is required to completely comprehend the scope of the resources. The integration of borehole data and the alignment of geological sections with inversion models confirmed the validity of the conclusions. The core samples that were retrieved show a lot of different minerals, including valuable ores and minerals that have been changed. Pyrite and molybdenite are always found together. These findings establish a solid basis for further investigation and the sustainable management of resources. This study contributes to the understanding of the Qiushuwan Cu-Mo deposit and advances exploration techniques using the spread spectrum-induced polarization (SSIP) method. It provides useful information for geologists, mining professionals, and stakeholders involved in resource usage.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"125 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215152","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}
With the increasing depletion of shallow resources, mining has gradually shifted to deeper levels, and the high-temperature problem of deep mining has restricted the efficient and safe development of mining. In this study, five types of thermal insulation materials for surrounding rocks with different ratios were produced using tailings, P.O.32.5 clinker, aluminum powder, glass beads, quick lime, and slaked lime as test materials. Based on the uniaxial compression test, the thermal constant analysis test, and numerical simulation analysis technology, the change rule of mortar compressive strength and thermal conductivity was analyzed, and the cooling effect of surrounding-rock thermal insulation materials with different ratios was discussed. The results showed that the compressive strength of the surrounding-rock thermal insulation materials ranged from 0.39 to 0.53 MPa, and the thermal conductivity ranged from 0.261 to 0.387 W/(K·m), with the compressive strength of ratio E being the largest and the thermal conductivity of ratio A being the lowest. In the numerical simulation analysis results, the thermal insulation layer thickness was taken as a value of 10 cm when, at this time, the best thermal insulation effect and economic benefits involved a temperature reduction of 0.9 K. In the case of changing the thermal conductivity and inlet wind speed, the original temperature of the rock temperature reduction was also very clear, with maximum reductions of 0.92 K, 0.92 K, and 1.42 K.
{"title":"Experimentation of Heat-Insulating Materials for Surrounding Rocks in Deep Mines and Simulation Study of Temperature Reduction","authors":"Hongwei Deng, Yuanzhe Xiao","doi":"10.3390/min14090938","DOIUrl":"https://doi.org/10.3390/min14090938","url":null,"abstract":"With the increasing depletion of shallow resources, mining has gradually shifted to deeper levels, and the high-temperature problem of deep mining has restricted the efficient and safe development of mining. In this study, five types of thermal insulation materials for surrounding rocks with different ratios were produced using tailings, P.O.32.5 clinker, aluminum powder, glass beads, quick lime, and slaked lime as test materials. Based on the uniaxial compression test, the thermal constant analysis test, and numerical simulation analysis technology, the change rule of mortar compressive strength and thermal conductivity was analyzed, and the cooling effect of surrounding-rock thermal insulation materials with different ratios was discussed. The results showed that the compressive strength of the surrounding-rock thermal insulation materials ranged from 0.39 to 0.53 MPa, and the thermal conductivity ranged from 0.261 to 0.387 W/(K·m), with the compressive strength of ratio E being the largest and the thermal conductivity of ratio A being the lowest. In the numerical simulation analysis results, the thermal insulation layer thickness was taken as a value of 10 cm when, at this time, the best thermal insulation effect and economic benefits involved a temperature reduction of 0.9 K. In the case of changing the thermal conductivity and inlet wind speed, the original temperature of the rock temperature reduction was also very clear, with maximum reductions of 0.92 K, 0.92 K, and 1.42 K.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"63 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142226997","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}
The Hongnipo deposit, a newly discovered large copper deposit in the Kangdian Fe-Cu metallogenic belt of southwest China, is hosted in the Paleoproterozoic metavolcanic and metasedimentary rocks of the Hekou group. The deposit comprises five strata-bound ore bodies and is associated with sporadically distributed gabbroic intrusions. Four stages of mineralization and alteration have been identified: sodic alteration (I), banded sulfide (II), magnetite (III), and sulfide vein/stockwork (IV). Extensive sodic alteration of stage I is confirmed by the composition of feldspars. Trace element analysis of magnetite suggests a formation temperature of 400 ± 50 °C and has a characteristic of IOCG deposits, while high δ18O values (8.3–11.0‰) of fluids from stage III indicate a magmatic water origin. Sulfide δ34SVCDT values from stages II and IV range from −2.6 to 10.9‰ and −1.5 to 9.9‰, respectively, suggesting a mixed sulfur source from magmatic H2S and reduced seawater sulfate. Chalcopyrite from Hongnipo shows a narrow δ65Cu range of −0.135 to 0.587‰, indicating formation at high temperatures. The lack of correlation between δ65Cu and δ34SVCDT values suggests distinct geochemical behaviors in mineralization. In summary, the Hongnipo deposit is classified as a Cu-rich section of a typical IOCG deposit.
{"title":"Geology and Geochemistry of the Hongnipo Copper Deposit, Southwest China","authors":"Wangdong Yang, Gongwen Wang, Yunchou Xu","doi":"10.3390/min14090936","DOIUrl":"https://doi.org/10.3390/min14090936","url":null,"abstract":"The Hongnipo deposit, a newly discovered large copper deposit in the Kangdian Fe-Cu metallogenic belt of southwest China, is hosted in the Paleoproterozoic metavolcanic and metasedimentary rocks of the Hekou group. The deposit comprises five strata-bound ore bodies and is associated with sporadically distributed gabbroic intrusions. Four stages of mineralization and alteration have been identified: sodic alteration (I), banded sulfide (II), magnetite (III), and sulfide vein/stockwork (IV). Extensive sodic alteration of stage I is confirmed by the composition of feldspars. Trace element analysis of magnetite suggests a formation temperature of 400 ± 50 °C and has a characteristic of IOCG deposits, while high δ18O values (8.3–11.0‰) of fluids from stage III indicate a magmatic water origin. Sulfide δ34SVCDT values from stages II and IV range from −2.6 to 10.9‰ and −1.5 to 9.9‰, respectively, suggesting a mixed sulfur source from magmatic H2S and reduced seawater sulfate. Chalcopyrite from Hongnipo shows a narrow δ65Cu range of −0.135 to 0.587‰, indicating formation at high temperatures. The lack of correlation between δ65Cu and δ34SVCDT values suggests distinct geochemical behaviors in mineralization. In summary, the Hongnipo deposit is classified as a Cu-rich section of a typical IOCG deposit.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"28 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215154","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}
Nuriya R. Ayupova, Valery V. Maslennikov, Irina Yu. Melekestseva, Dmitry A. Artemyev, Elena V. Belogub
The formation of Paleozoic silica–iron-rich sedimentary rocks in the Urals volcanic-hosted massive sulfide (VHMS) deposits is considered a result of seafloor alteration of hyaloclastites mixed with calcareous/organic or sulfide material. These rocks host various Ti mineral phases pointing to the transformation of precursor metacolloidal TiO2 phases to disordered anatase during seafloor alteration of hyaloclastites, which was later converted to globules and clusters and further to diagenetic rutile. The LA-ICP-MS analysis showed that the Ti content of hyaloclasts partly replaced by finely dispersed Si–Fe aggregates increases to 540–2950 ppm and decreases (<5 ppm) in full Si–Fe pseudomorphs after hyaloclasts. LA-ICP-MS element mapping reveals the enrichment in V, U, Cr, W, Nb, Pb, and Th of the anatase globules and the local accumulation of Zr, Y, and REE on their periphery. Corrosive biogenic textures in the outer zones of some hyaloclasts and biomorphic aggregates in rocks contain anatase particles in assemblage with apatite indicating the biophilic properties of Ti. This work fills the knowledge gaps about Ti mobilization during low-temperature seafloor alteration of hyaloclastites in VHMS deposits.
乌拉尔火山成因块状硫化物（VHMS）矿床中古生代富硅铁沉积岩的形成被认为是混有钙钛矿/有机物或硫化物物质的透明闪长岩海底蚀变的结果。这些岩石中含有各种钛矿物相，表明在透明闪长岩的海底蚀变过程中，前驱体元古代二氧化钛相转变为无序锐钛矿，随后转变为球状和团状，并进一步转变为成岩金红石。LA-ICP-MS 分析表明，部分被细微分散的硅-铁聚集体取代的透明钙钛矿中的 Ti 含量增加到 540-2950 ppm，而透明钙钛矿之后的全硅-铁假晶中的 Ti 含量则下降（<5 ppm）。LA-ICP-MS元素图谱显示，锐钛矿球粒富含V、U、Cr、W、Nb、Pb和Th元素，Zr、Y和REE元素在其外围局部聚集。岩石中一些透明碎屑岩和生物形态聚集体外部区域的腐蚀性生物成因纹理含有锐钛矿颗粒与磷灰石的集合体，这表明了钛的亲生物特性。这项研究填补了有关VHMS矿床中透明沸石低温海底蚀变过程中Ti迁移的知识空白。
{"title":"The Fate of “Immobile” Ti in Hyaloclastites: An Evidence from Silica–Iron-Rich Sedimentary Rocks of the Urals Paleozoic Massive Sulfide Deposits","authors":"Nuriya R. Ayupova, Valery V. Maslennikov, Irina Yu. Melekestseva, Dmitry A. Artemyev, Elena V. Belogub","doi":"10.3390/min14090939","DOIUrl":"https://doi.org/10.3390/min14090939","url":null,"abstract":"The formation of Paleozoic silica–iron-rich sedimentary rocks in the Urals volcanic-hosted massive sulfide (VHMS) deposits is considered a result of seafloor alteration of hyaloclastites mixed with calcareous/organic or sulfide material. These rocks host various Ti mineral phases pointing to the transformation of precursor metacolloidal TiO2 phases to disordered anatase during seafloor alteration of hyaloclastites, which was later converted to globules and clusters and further to diagenetic rutile. The LA-ICP-MS analysis showed that the Ti content of hyaloclasts partly replaced by finely dispersed Si–Fe aggregates increases to 540–2950 ppm and decreases (<5 ppm) in full Si–Fe pseudomorphs after hyaloclasts. LA-ICP-MS element mapping reveals the enrichment in V, U, Cr, W, Nb, Pb, and Th of the anatase globules and the local accumulation of Zr, Y, and REE on their periphery. Corrosive biogenic textures in the outer zones of some hyaloclasts and biomorphic aggregates in rocks contain anatase particles in assemblage with apatite indicating the biophilic properties of Ti. This work fills the knowledge gaps about Ti mobilization during low-temperature seafloor alteration of hyaloclastites in VHMS deposits.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"8 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215191","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}
Wei Wang, Sichun Hu, Shoujing Wang, Hongzhao Liu, Deshui Yu, Lin Liu, Hongliang Wang, Ke Wang
In this paper, the process of solid-state metalized reduction and magnetic separation was investigated for preparation of nickel–iron concentrate from a low-grade laterite nickel ore. The effects of reduction temperature, reduction time, amount of dosages, and magnetic field strength on grades and recoveries of nickel and iron were studied. The results showed that nickel–iron concentrate with a nickel grade of 7.32%, nickel recovery of 81.84%, iron grade of 78.74%, and iron recovery of 69.78% were obtained under the conditions of a reduction temperature of 1200 °C, reduction time of 120 min, calcium fluoride addition of 12%, ferric oxide addition of 10%, coal addition of 12%, and magnetic field strength of 170 kA/m.
{"title":"Preparation of Nickel–Iron Concentrate from Low-Grade Laterite Nickel Ore by Solid-State Metalized Reduction and Magnetic Separation","authors":"Wei Wang, Sichun Hu, Shoujing Wang, Hongzhao Liu, Deshui Yu, Lin Liu, Hongliang Wang, Ke Wang","doi":"10.3390/min14090926","DOIUrl":"https://doi.org/10.3390/min14090926","url":null,"abstract":"In this paper, the process of solid-state metalized reduction and magnetic separation was investigated for preparation of nickel–iron concentrate from a low-grade laterite nickel ore. The effects of reduction temperature, reduction time, amount of dosages, and magnetic field strength on grades and recoveries of nickel and iron were studied. The results showed that nickel–iron concentrate with a nickel grade of 7.32%, nickel recovery of 81.84%, iron grade of 78.74%, and iron recovery of 69.78% were obtained under the conditions of a reduction temperature of 1200 °C, reduction time of 120 min, calcium fluoride addition of 12%, ferric oxide addition of 10%, coal addition of 12%, and magnetic field strength of 170 kA/m.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"42 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215156","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}
Valentin Afanasiev, Vladimir Kovalevsky, Alexander Yelisseyev, Rudolf Mashkovtsev, Sergey Gromilov, Sargylana Ugapeva, Ekaterina Barabash, Oksana Ivanova, Anton Pavlushin
Carbonado is a specific variety of diamonds, typical representatives of which are distributed in the diamond placers of Central Africa, Brazil, and Venezuela. Carbonado consists of the microcrystalline aggregates of diamonds, with inclusions of mineral matter. These aggregates appear as fragments that are rounded to varying degrees. Carbonado has been known for a long time, but its primary sources have not been found and its genesis remains unclear. We have substantiated the hypothesis that the most probable precursor of carbonado is shungite. Shungite is a specific form of non-crystalline, non-graphitic, fullerene-like carbon. Shungite rocks, currently known in Karelia (Russia), are natural microdispersed composite materials containing shungite—carbonaceous matter and mineral components of different compositions. The content of carbonaceous matter in shungite rocks is from less than 10% to 98%. The carbon isotopic composition of shungite is light ẟ13C from −25‰ to −40‰. The age of shungite rock is more than 2 billion years old, but earlier shungite was probably much more widespread. Known shungite rocks are more than 2 billion years old, but earlier shungite was probably much more widespread. Shungite rocks could recrystallize into diamond rock upon subduction to high pressure and temperature. The diamond rocks could then be exhumed to the Earth’s surface, where they could undergo disruption and reworking with formation of those very fragments that are known as “carbonado”.
{"title":"About the Origin of Carbonado","authors":"Valentin Afanasiev, Vladimir Kovalevsky, Alexander Yelisseyev, Rudolf Mashkovtsev, Sergey Gromilov, Sargylana Ugapeva, Ekaterina Barabash, Oksana Ivanova, Anton Pavlushin","doi":"10.3390/min14090927","DOIUrl":"https://doi.org/10.3390/min14090927","url":null,"abstract":"Carbonado is a specific variety of diamonds, typical representatives of which are distributed in the diamond placers of Central Africa, Brazil, and Venezuela. Carbonado consists of the microcrystalline aggregates of diamonds, with inclusions of mineral matter. These aggregates appear as fragments that are rounded to varying degrees. Carbonado has been known for a long time, but its primary sources have not been found and its genesis remains unclear. We have substantiated the hypothesis that the most probable precursor of carbonado is shungite. Shungite is a specific form of non-crystalline, non-graphitic, fullerene-like carbon. Shungite rocks, currently known in Karelia (Russia), are natural microdispersed composite materials containing shungite—carbonaceous matter and mineral components of different compositions. The content of carbonaceous matter in shungite rocks is from less than 10% to 98%. The carbon isotopic composition of shungite is light ẟ13C from −25‰ to −40‰. The age of shungite rock is more than 2 billion years old, but earlier shungite was probably much more widespread. Known shungite rocks are more than 2 billion years old, but earlier shungite was probably much more widespread. Shungite rocks could recrystallize into diamond rock upon subduction to high pressure and temperature. The diamond rocks could then be exhumed to the Earth’s surface, where they could undergo disruption and reworking with formation of those very fragments that are known as “carbonado”.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"17 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215195","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}
A unique Li–Na metasomatic rock from Iwagi Islet in Southwest (SW) Japan is an episyenite that contains new Li-rich minerals, including sugilite, katayamalite, murakamiite, and ferro-ferri-holmquistite. We present petrographical, mineralogical, and geochronological data for the protoliths and episyenite. We classified the metasomatic rocks based on the mineral assemblages, from the protolith biotite granite to albitized granite, quartz albitite, hedenbergite albitite, aegirine albitite, sugilite albitite, and katayamalite albitite. The protolith of hedenbergite albitites may have been metasomatic granite that has been subjected to calcic skarnization. Albitites are formed related to fractures and shear zones that focused the fluid flow and metasomatism. Extensive albitization and formation of abundant Li minerals requires involvement of external Li-Na-Cl-rich fluids, which might be related to deep high-temperature Arima-like brines derived from dehydration of the subducted oceanic slab. Formation of the albitites began with quartz dissolution and vug formation, and record interface-coupled dissolution–reprecipitation processes in an open system. The 40Ar/39Ar age of 91.5 ± 0.3 Ma determined for the katayamalite is slightly younger than the protolith zircon U–Pb age of 93.5 ± 1.7 Ma (Turonian), reasonably explaining the timing of Li–Na metasomatism after the petrogenesis of host granites.
{"title":"Petrogenesis of an Episyenite from Iwagi Islet, Southwest Japan: Unique Li–Na Metasomatism during the Turonian","authors":"Teruyoshi Imaoka, Sachiho Akita, Tsuyoshi Ishikawa, Kenichiro Tani, Jun-Ichi Kimura, Qing Chang, Mariko Nagashima","doi":"10.3390/min14090929","DOIUrl":"https://doi.org/10.3390/min14090929","url":null,"abstract":"A unique Li–Na metasomatic rock from Iwagi Islet in Southwest (SW) Japan is an episyenite that contains new Li-rich minerals, including sugilite, katayamalite, murakamiite, and ferro-ferri-holmquistite. We present petrographical, mineralogical, and geochronological data for the protoliths and episyenite. We classified the metasomatic rocks based on the mineral assemblages, from the protolith biotite granite to albitized granite, quartz albitite, hedenbergite albitite, aegirine albitite, sugilite albitite, and katayamalite albitite. The protolith of hedenbergite albitites may have been metasomatic granite that has been subjected to calcic skarnization. Albitites are formed related to fractures and shear zones that focused the fluid flow and metasomatism. Extensive albitization and formation of abundant Li minerals requires involvement of external Li-Na-Cl-rich fluids, which might be related to deep high-temperature Arima-like brines derived from dehydration of the subducted oceanic slab. Formation of the albitites began with quartz dissolution and vug formation, and record interface-coupled dissolution–reprecipitation processes in an open system. The 40Ar/39Ar age of 91.5 ± 0.3 Ma determined for the katayamalite is slightly younger than the protolith zircon U–Pb age of 93.5 ± 1.7 Ma (Turonian), reasonably explaining the timing of Li–Na metasomatism after the petrogenesis of host granites.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"97 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215192","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}
The Dashigou deposit is one of the most representative carbonatite-type Mo-REE deposits in the East Qinling metallogenic belt of China, with a molybdenum resource of more than 180 kt and a rare earth resource of 37.8 kt. Recent exploration has revealed a considerable scale of uranium mineralization within this deposit. Therefore, this study conducted detailed mineralogical and EPMA U-Th-Pb chemical dating on the uranium mineralization in the Dashigou deposit. The results indicate that the U-ore body in the Dashigou deposit mainly consists in carbonatite veins, and principally as anhedral, mesh-like uraninite. The mineral assemblage is characterized by uraninite + rutile + bastnasite + parisite or brannerite. The uraninite displays geochemical compositions of high Y and Ce and low Si, Ti, and Mg. The EPMA U-Th-Pb chemical dating is 144 ± 3.1 Ma, representing the Yanshanian uranium mineralization age in the region. The newly discovered uranium mineralization age indicates that the deposit experienced a uranium remobilization event during the Cretaceous and was formed in an intracontinental orogenic and extensional environment post-collision orogeny.
{"title":"The Yanshanian Uranium Mineralization Age and Its Geological Significance in the Dashigou Carbonatite-Type Mo-REE-U Deposit, East Qinling Orogen, China","authors":"Guangwen Huang, Dehai Wu, Furong Li, Chunrong Pan, Pengfei Fan, Zhuang Min","doi":"10.3390/min14090928","DOIUrl":"https://doi.org/10.3390/min14090928","url":null,"abstract":"The Dashigou deposit is one of the most representative carbonatite-type Mo-REE deposits in the East Qinling metallogenic belt of China, with a molybdenum resource of more than 180 kt and a rare earth resource of 37.8 kt. Recent exploration has revealed a considerable scale of uranium mineralization within this deposit. Therefore, this study conducted detailed mineralogical and EPMA U-Th-Pb chemical dating on the uranium mineralization in the Dashigou deposit. The results indicate that the U-ore body in the Dashigou deposit mainly consists in carbonatite veins, and principally as anhedral, mesh-like uraninite. The mineral assemblage is characterized by uraninite + rutile + bastnasite + parisite or brannerite. The uraninite displays geochemical compositions of high Y and Ce and low Si, Ti, and Mg. The EPMA U-Th-Pb chemical dating is 144 ± 3.1 Ma, representing the Yanshanian uranium mineralization age in the region. The newly discovered uranium mineralization age indicates that the deposit experienced a uranium remobilization event during the Cretaceous and was formed in an intracontinental orogenic and extensional environment post-collision orogeny.","PeriodicalId":18601,"journal":{"name":"Minerals","volume":"23 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142215194","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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