Article
Multidisciplinary Sciences
Yu Wang, Stephen F. Foley, Stephan Buhres, Jeremie Soldner, Yigang Xu
Summary: Potassium-rich volcanism occurring throughout the Alpine-Himalayan belt from Spain to Tibet is characterized by unusually high Th/La ratios, which may be attributed to a new mantle lithosphere formed only 20 to 50 million years earlier at shallow depths without deep subduction of continental materials. This mechanism is consistent with a temporal trend in Th/La in potassic postcollisional magmas, indicating shallow sources in accretionary settings.
Article
Mineralogy
Yves Moelo
Summary: A new occurrence of pyrite crystals with rhombohedral habit is described from the Madan Pb-Zn ore field. The crystallographic point group of these crystals is (3) over bar, and they are considered as a dimorph of cubic pyrite, known as pseudo-cubic trigonal pyrite (pyrite-R). Four types of twinning have been distinguished, including three contact twins and one penetration twin. Twinning by metric merohedry confirms the symmetry decrease in these crystals.
EUROPEAN JOURNAL OF MINERALOGY
(2023)
Article
Geochemistry & Geophysics
Ji Shen, Ying-Nan Zhang, Yi-Zeng Yang, Liping Qin, Yongsheng He, Sheng-Ao Liu, Fangyue Wang, Huaiwei Ni
Summary: Molybdenum (Mo) isotopes can be fractionated during redox-related hydrothermal and Earth's surface processes. Different types of rocks exhibit distinct Mo isotope compositions, which are influenced by magmatic evolution, hydrothermal alteration, and multiple-end-member mixing trends.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geosciences, Multidisciplinary
Peter Marchev, Raya Raicheva, Stoyan Georgiev, Ivan P. Savov, Danko Jelev
Summary: The study presents a possible model for the formation of ultrapotassic rocks based on the analysis of a monzonite intrusion in the Central Rhodope Massif in Bulgaria. The monzonite shows evidence of extensive crustal assimilation and hybridization with primitive mantle-derived magma, leading to its ultrapotassic composition.
GEOLOGICAL MAGAZINE
(2022)
Article
Geochemistry & Geophysics
Heng-Ci Tian, Shi-Hong Tian, Zeng-Qian Hou, Zhi-Ming Yang, Yuanchuan Zheng
Summary: By studying rocks from the Qulong region in southern Tibet, it was found that these rocks were most likely formed by various degrees of partial melting and fractional crystallization from the same source. The Li isotope composition did not show significant fractionation during partial melting and magma differentiation. The Cu mineralization was related to magmatic fluids exsolved from a deep magma chamber.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geosciences, Multidisciplinary
Yan Jing, Wenchun Ge, M. Santosh, Yu Dong, Hao Yang, Zheng Ji, Junhui Bi, Hongying Zhou, Dehe Xing
Summary: Studying rocks from the Early Mesozoic can provide insights into the melting processes during the closure of the Paleo-Asian Ocean. The granite porphyry is likely derived from partial melting of subducting Paleo-Asian oceanic crust, while the Nb-enriched mafic rocks are related to subduction and likely derived from the interaction between peridotitic mantle wedge and oceanic slab-derived adakitic melts.
GEOSCIENCE FRONTIERS
(2022)
Article
Geology
Jian-Kang Yi, Di-Cheng Zhu, Roberto F. Weinberg, Qing Wang, Jin-Cheng Xie, Liang-Liang Zhang, Zhi-Dan Zhao
Summary: This study investigates the source of post-collisional Oligocene high-K adakitic granites in southern Tibet and provides evidence for their generation through melting of intermediate to felsic arc rocks. It concludes that high-K adakitic magmas are derived from melting of older intermediate to felsic arc rocks at intermediate pressures, without any involvement of HP melting of metabasaltic rocks.
Article
Geochemistry & Geophysics
Chenglai Deng, Changqing Hu, Ming Li, Wu Li
Summary: The study found that the Shangcheng pluton consists of adakitic rocks, and the enrichment of iron isotopes cannot be explained by weathering/alteration and fluid exsolution. Fractional crystallization of magnetite may account for the variability of iron isotopes in certain rocks.
Article
Geosciences, Multidisciplinary
Svenja Trapp, Marian Janak, Kathrin Fassmer, Nikolaus Froitzheim, Carsten Muenker, Neven Georgiev
Summary: The study confirms ultra-high-pressure metamorphism in the Rhodope Metamorphic Complex in Bulgaria and determines the Variscan age of metamorphism through Lu-Hf dating of garnet-whole-rock. By analyzing eclogite samples from Belica and Gega, the research reveals the metamorphic processes and ages in these regions.
Article
Multidisciplinary Sciences
Violina Angelova, Daniela Kovacheva
Summary: This study aims to characterize serpentine soils in Bulgaria and examine the biogeochemistry of pedogenic Ni and its relation to Ni available forms. The results show that serpentine soils in Bulgaria have high content of Ni, neutral to slightly alkaline reaction and medium to high organic matter content. The primary minerals present in the soil samples include serpentine group, talc group, amphibole group, feldspar group and quartz. The secondary minerals include calcite, dolomite, clinochlore and montmorillonite. The forms of iron oxides in the soils significantly affect the availability of Ni.
COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES
(2023)
Article
Geochemistry & Geophysics
Zhi-Wei Song, Chang-Qing Zheng, Chen-Yue Liang, Bo Lin, Xue-Chun Xu, Quan-Bo Wen, Ying-Li Zhao, Cheng-Gang Cao, Zhi-Xin Wang
Summary: The study of Early Jurassic volcanic rocks in Western Liaoning provides insights into the evolution of volcanic magma source and composition, crust-mantle interaction, craton destruction, and oceanic plate subduction. Through detailed petrography, dating, geochemistry, and isotopic studies, it is revealed that these intermediate-acidic volcanic rocks were derived from the partial melting of the lower crust, influenced by the long-range tectonic effects in the Early Jurassic.
Article
Geochemistry & Geophysics
Tian -Yu Lu, Zhen-Yu He, Reiner Klemd
Summary: The adakitic magmatism in southern Tibet, after the collision between India and Eurasia, is believed to originate from the partial melting of the thickened lower crust in Lhasa. However, little attention has been given to the magma differentiation processes following the formation of the adakitic melts. In this study, in situ zircon trace-element geochemistry and whole-rock geochemical data are used to understand the magma differentiation and mineralization of post-onset collision adakitic magmatism in the southern Lhasa subterrane. Results show that specific minerals (titanite, magnetite) underwent fractional crystallization in the ca. 30 Ma monzogranite, while the ca. 15 Ma granodiorite experienced equilibrium crystallization. Thermodynamic modeling also supports these findings. Reduced oxygen fugacity conditions during magnetite fractionation led to sulfide segregation and the removal of sulfur and chalcophile elements like Ni and Cu. This suggests that magnetite fractionation in the shallow to mid-continental crust may contribute to the low Cu fertility of magmas, forming Cu-poor post-onset collision adakitic rocks in the Gangdese magmatic belt.
Article
Geology
Wei Wang, Qing-Guo Zhai, Pei-Yuan Hu, Sun-Lin Chung, Yue Tang, Hai-Tao Wang, Zhi-Cai Zhu, Hao Wu, Zhi-Qiang Huang
Summary: Research suggests that adakitic dacite in the Rutog area of western Tibetan Plateau may have been formed due to the northward subduction of the Indus-Yarlung Zangbo oceanic lithosphere, triggering Late Cretaceous magmatism. This finding provides new insights into the geodynamic evolution of the Indus-Yarlung Zangbo Neo-Tethys Ocean.
INTERNATIONAL GEOLOGY REVIEW
(2021)
Article
Geology
Yu-Song Chen, Zheng-Hong Liu, Qing-Bin Guan, Le Wan, Jin Liu, Tian-Yu Gao
Summary: This research presents new chronological and geochemical data on adakitic rocks in the Baishan area, southeastern Jilin Province, China, indicating four stages of adakitic magmatism with different tectonic settings, including compressional, extensional, and subduction-related settings, in response to tectonic events such as the closure of the Paleo-Asian Ocean, collision between the North China Craton and Yangtze Craton, and subduction of the Paleo-Pacific Plate during the Mesozoic.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geology
Sun HaoZhe, Zhao ZhiDan, Zhu DiCheng, Liu Dong, Wang Qing, Tang Yan, Qi NingYuan, Dong GuoChen
Summary: The study indicates that the Miocene volcanic rocks in the Milashan area show adakitic affinity and may have formed through partial melting of the lower crust, with a source region possibly being garnet amphibolite. Additionally, the volcanic rocks formed simultaneously with the Milashan fault, suggesting that both phenomena may have been caused by lithosphere delamination of the Lhasa terrane.
ACTA PETROLOGICA SINICA
(2021)
Article
Geochemistry & Geophysics
Ezequiel Garcia Morabito, Alejandro Beltran-Trivino, Carla M. Terrizzano, Florencia Bechis, Jeremias Likerman, Albrecht Von Quadt, Victor A. Ramos
Summary: Theoretical studies suggest that the dynamics of actively deforming mountain ranges are affected by variations in climate. A study in North Patagonia analyzes the spatial patterns of deformation and their temporal variations to evaluate potential feedbacks between climate and deformation. The data indicate a decrease in shortening rates and subsidence after a period of widespread deformation and uplift, with subsequent structural reorganization marked by enhanced erosion and slip on interior faults.
Article
Geology
Nikolay Bonev, Petyo Filipov, Raya Raicheva, Robert Moritz
Summary: The metamorphic basement of the Sakar-Strandzha Zone in southeast Bulgaria is mainly composed of Late Palaeozoic to Middle Triassic granitoids, meta-granitoids, and meta-volcanic rocks, with similar compositions and tectonic settings, indicating a common regional tectono-magmatic event during the late Palaeozoic to early Mesozoic era.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geosciences, Multidisciplinary
Irena Peytcheva, Albrecht Von Quadt, Vladislav Kostov-Kytin, Milen Kadiyski, Milen Stavrev
Summary: This study focuses on Ta-Nb oxides from Vishteritsa rare-element beryl-columbite LCT pegmatites in the Western Rhodopes, Bulgaria, as a significant source of strategic rare metals for high-tech products and green energy. U/Pb age data from columbite, LA-ICP-MS-U-Pb technique, and a new X36 columbite standard reference material are presented, supporting an Early Eocene magmatic period in the Western Rhodopes. EPMA data on columbite composition and in-situ LA-ICP-MS analysis reveal enrichment in heavy rare earth elements and a high UO2 content, indicating crystallization from highly fractionated fluid-rich magma and U-mobility during overprinting hydrothermal processes.
GEOLOGICA CARPATHICA
(2021)
Article
Geology
Alejandro Piraquive, Andreas Kammer, Matthias Bernet, Thomas Cramer, Albrecht von Quadt, Cristhian Gomez
Summary: The Sierra Nevada de Santa Marta Massif in the Northern Andes provides insights into the structural evolution of the lower crust through a series of tectono-metamorphic events. These events, revealed through geological dating and geochemical analysis, have shaped the complex crustal section of the region, highlighting the tectonic processes that have occurred over millions of years.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geosciences, Multidisciplinary
Mihovil Brlek, Sean P. Gaynor, Giovanni Mongelli, Blanca Bauluz, Rosa Sinisi, Vlatko Brcic, Irena Peytcheva, Ivan Micur, Simon Tapster, Nina Trinajstic, Elisa Laita, Alfonso Yuste, Sanja Suica, Anita Grizelj, Duje Kukoc, Urs Schaltegger
Summary: The study shows that the CK bauxites formed in situ during the Miocene Climatic Optimum, with a maximum depositional age of approximately 16.9576 Ma, coinciding with the onset of the MCO.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2021)
Article
Geosciences, Multidisciplinary
Peter Marchev, Raya Raicheva, Stoyan Georgiev, Ivan P. Savov, Danko Jelev
Summary: The study presents a possible model for the formation of ultrapotassic rocks based on the analysis of a monzonite intrusion in the Central Rhodope Massif in Bulgaria. The monzonite shows evidence of extensive crustal assimilation and hybridization with primitive mantle-derived magma, leading to its ultrapotassic composition.
GEOLOGICAL MAGAZINE
(2022)
Article
Geosciences, Multidisciplinary
Nikolay Bonev, Petyo Filipov, Raya Raicheva, Robert Moritz
Summary: The clastic units studied in southeast Bulgaria originated from recycled continental arc acid rocks, with U-Pb detrital zircon geochronology revealing depositional ages ranging from Late Permian to Late Triassic. The main source of detrital zircons is from Late Carboniferous-Permian and Middle Triassic magmatic bodies, with significant clusters also originating from Proterozoic-Neoarchean and Neoproterozoic-Cambrian magmatic arc systems. The detrital zircon record in the Sakar-Strandzha Zone is similar to adjacent zones, indicating a common Paleozoic paleogeographic position.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
J. Hoerler, A. Von Quadt, R. Burkhard, I. Peytcheva, V. Cvetkovic, T. Baker
Summary: The Karavansalija Mineralized Center in southwestern Serbia belongs to the Oligocene Serbo-Macedonian magmatic and metallogenic belt. The study reveals the subduction-derived origin of the magmas and the process of skarn mineralization through plagioclase-absent, high-pressure amphibole +/- garnet fractionation. The age and evolution of the mineralization are determined by analyzing the zircon age and trace elements.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geosciences, Multidisciplinary
Nikolay Bonev, Massimo Chiaradia, Robert Moritz
Summary: This study focuses on the carbonate sequences in the Sakar-Strandzha Zone (SASTZ) in Bulgaria, which contain the Sakar, Subbalkanide, and Strandzha facies types. Strontium isotopic compositions of various carbonate samples indicate different depositional ages, with the Sakar unit confirming an Early-Middle Triassic age, other Sakar-type sections suggesting an Early Permian age, the Strandzha-type carbonate sample indicating a Middle Triassic age, and a few Subbalkanide-type samples indicating an Early Devonian age. These findings suggest the need for a reassessment of the Subbalkanide-type Triassic and some Sakar-type inferred Triassic carbonate sequences in the SASTZ.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Nikolay Bonev, Zornitsa Dotseva, Massimo Chiaradia
Summary: We present the isotopic compositions of mafic rocks from the Jurassic supra-subduction zone Evros ophiolite in northeastern Greece. These rocks show a mixture of mantle-derived MORB component and crustal material and/or sediment in their melt source, indicating an intra-oceanic arc origin. The isotopic signatures of the Evros ophiolite rocks are comparable to those of mafic rocks from the Mandritsa unit in Bulgaria.
GEOLOGICAL MAGAZINE
(2023)
Article
Geochemistry & Geophysics
Elitsa Stefanova, Stoyan Georgiev, Irena Peytcheva, Peter Marchev, Albrecht von Quadt, Raya Raicheva, Ianko Gerdjikov, Kalin Kouzmanov, Adrian Boyce, Torsten Vennemann
Summary: The Elatsite-Chelopech ore field in Central Bulgaria is rich in porphyry copper and epithermal gold deposits and prospects. Pyrite, arsenopyrite, and sulfosalt minerals are major carriers for valuable elements such as Au, Ag, Sb, Se, and Co. Lead and sulfur isotopic signatures suggest a genetic link between porphyry copper and base metal deposits.
Article
Multidisciplinary Sciences
Peter Marchev, Raya Raicheva, Rositsa Ivanova, Irena Peytcheva, Valentin Grozdev
Summary: This study provides U-Pb zircon ages for a tuff bed in the volcano-sedimentary sequence in Lemnos, Greece, suggesting synchronicity with a known eruption. Comparisons with age data from other European localities indicate a widespread ash distribution over more than 1,000,000 km(2). The study concludes that the Borovitsa volcano may have had two supereruptions separated by 0.5 Ma.
COMPTES RENDUS DE L ACADEMIE BULGARE DES SCIENCES
(2021)
Article
Geochemistry & Geophysics
Huichuan Liu, Alan R. Hastie, Chiara Maria Petrone
Summary: This study conducted isotope analyses on two ocean island basalt (OIB)-associated enriched mafic intrusions in the Yunnan-Burma region, and found that these rocks may have originated from the subduction recycling of marine sediments and altered oceanic crust.
Article
Geochemistry & Geophysics
L. Notini, M. Scambelluri, A. Tommasi, A. Zanetti, F. Ferri, A. Rodriguez-Vargas, E. Rampone
Summary: This study provides important petrologic information on the mantle wedge above an active subduction zone in Southern Colombia. The researchers analyzed a unique suite of rock samples and found evidence of hydration, metasomatism, and partial melting in the mantle wedge. They also observed variations in lithotypes, textures, and mineral abundance, indicating different interactions with melts and fluids. This study sheds light on the complex petrological processes occurring in the mantle wedge and contributes to our understanding of subduction zone dynamics.
Article
Geochemistry & Geophysics
Sourav Bhattacharjee, Aniket Chakrabarty, Roger H. Mitchell, Suresh Chandra Patel, Evgeniy N. Kozlov, Ekaterina N. Fomina, Monojit Dey, Supratim Pal
Summary: The Hogenakkal complex in India consists of silicate-rich and silicate-poor carbonatites and clinopyroxenites. The formation of carbonatite is influenced by silicate minerals. The carbohydrothermal mineralization in the carbonatites is induced by magma-derived fluids and interactions with the surrounding rocks.
Article
Geochemistry & Geophysics
Jia-Min Wang, Kyle Patrick Larson, Jin-Jiang Zhang, Liang Zhao, Fu-Yuan Wu
Summary: The role of collisional belts in the global carbon budget is controversial. This study reveals a previously unrecognized carbon source in the collisional orogen of the Himalayas, where metamorphism of carbonate-bearing rocks in the hanging wall resulted in significant CO2 degassing.
Article
Geochemistry & Geophysics
Joseph Martial Akame, Elson Paiva Oliveira, Vinciane Debaille, Marc Poujol, Bernhard Schulz, Dieudonnee Bisso, Fabien Humbert, Serge Parfait Koah Na Lebogo, Philmont Zo'o Zame
Summary: Archean granitoids play key roles in the crustal evolution and can provide important insights into early geologic processes.
Article
Geochemistry & Geophysics
Xiguang Huang, Jun He, Jingxin Zhao, Jingzhao Dou, Weiyong Li, Aimin Hu, Ge Liu, Yiru Ji, Fukun Chen, Shuangqing Li
Summary: This study investigates the zircon ages and whole-rock geochemical data of Late Paleozoic magmatic rocks in the Western Yunnan Tethyan belt to identify the origin and mechanism of mantle melting. The results suggest that these magmatic rocks may originate from different mantle domains that were metasomatized by slab-derived fluids and sediment-derived melts.