Article
Geochemistry & Geophysics
Leon Glaser, Anna Grosche, Panagiotis C. Voudouris, Karsten M. Haase
Summary: This article discusses the genetic models for the formation of K-rich magmas and the magmatic activity in Limnos Island. New data on rocks and minerals reveal that the magmas underwent fractional crystallization without significant assimilation of crustal rocks. Isotope data suggests that the mantle source has been hybridized by subducted sedimentary material. The study also finds that the magmatic activity in Limnos Island is related to the subduction of continental crust.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2022)
Article
Geochemistry & Geophysics
Rachel Bezard, Simon Turner, Bruce Schaefer, Gene Yogodzinski, Kaj Hoernle
Summary: This study investigated the behavior of Re and Os during eclogite melting in primitive submarine lavas from the western Aleutian Arc. The results show that the Os-187/Os-188 of adakitic and non-adakitic volcanic rocks vary significantly but largely overlap, with the most radiogenic values occurring in samples with the lowest Os concentrations. The source of the adakites is unlikely to comprise significant eclogite-derived Os, suggesting minimal mobilization of Os during eclogite melting.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Chao Huang, Bin Chen, Keke Sun
Summary: A-type granites always co-exist with calc-alkaline granitoids in post-collisional settings. The source characteristics and formation P-T conditions of the two categories of A-types should be very different. Our data indicate that the calc-alkaline granitoids were derived mainly from melting of the Paleozoic metabasite that were buried deep in the lower crust. Re-melting of such a residue at even higher temperatures yielded a parental magma to the peralkaline A-type granites. This study confirms the previous experimental work on dehydration melting of calc-alkaline granitoids, and further indicates that the compositional discrepancies between experimental melts and natural A-types could be ascribed to the lack of fractionation processes in the former.
Article
Geochemistry & Geophysics
Stephen J. Turner, Charles H. Langmuir
Summary: Hydrous arc magmas are produced when water-bearing materials from subducted oceanic plates are transported to the mantle beneath volcanic arcs. The study shows that both sediment and ocean crust melt in arc volcanism, and the contribution of aqueous fluids to arc mass-balance is limited. Oxygen fugacity has a significant effect on slab melting. The research findings have important implications for understanding arc volcanism and the fluxes of elements into the deep mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Sunna Haroardottir, Simon Matthews, Saemundur A. Halldorsson, Matthew G. Jackson
Summary: In this study, a comprehensive geochemical database of Icelandic volcanic rocks was compiled to examine the spatial distribution and generation of geochemical heterogeneity in Iceland. The results show that mantle potential temperatures have a minor role, while lithospheric thickness plays a key role in generating geochemical heterogeneity.
Article
Geochemistry & Geophysics
Yan Hu, Fang-Zhen Teng, Catherine Chauvel
Summary: This study used stable potassium isotopes to track the crustal signatures in lavas from Martinique Island in the Lesser Antilles arc. The results show that the variations in K isotopes in these lavas are related to chemical parameters and radiogenic isotope ratios, indicating modification of mantle sources by input of subducted sediments. Most lavas have <1% to 5% of subducted sediments added to their mantle sources, with some samples showing divergence likely caused by the addition of K-bearing fluids from slab dehydration.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Aleisha C. Johnson, Zhe J. Zhang, Nicolas Dauphas, Roberta L. Rudnick, John D. Foden, Magali Toc
Summary: The isotopic compositions of titanium and iron in lavas and mineral separates from Rindjani Volcano in Indonesia show lower isotopic fractionations compared to other differentiation suites. This is attributed to the dominance of low-Ti magnetite and clinopyroxene as carriers of titanium in Rindjani lavas. The high Fe3+/Fe2+ ratio in calc-alkaline magmas like Rindjani leads to decreased titanium isotopic fractionation. Similarly, negligible iron isotopic fractionation is observed in Rindjani rocks and minerals due to their oxidized nature and similar Fe3+/Fe2+ ratios. Paired titanium and iron isotopic analyses can be a powerful tool for assessing oxygen fugacity during differentiation.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geosciences, Multidisciplinary
Eunjoo Choi, Marco L. Fiorentini, Andrea Giuliani, Stephen F. Foley, Roland Maas, Stuart Graham
Summary: The study revealed that the Proterozoic alkaline ultramafic rocks in the Yilgarn Craton and its northern margin have different origins, indicating varying mantle sources; the rocks from the Eastern Goldfields Superterrane and Norseman share similar compositions, possibly originating from a common mantle source; while the orangeites in the Earaheedy Basin show signatures of subduction-related magmas, suggesting an ancient lithospheric mantle source.
Article
Geochemistry & Geophysics
Antonio Castro
Summary: A non-basaltic cotectic array has been identified as a constraint on the origin of Andean-type batholiths, challenging models based on basaltic magmas and supporting the derivation of batholiths from non-basaltic magma precursors. The results of the study provide a new perspective on the formation of calc-alkaline batholiths at active continental margins.
Article
Multidisciplinary Sciences
Ming Tang, Xuanyu Liu, Kang Chen
Summary: A new hypothesis suggests that the high Mg/Fe ratio of the continental crust is linked to magma differentiation beneath high mountains. Research using geochemical data shows that andesites from mature continental arcs with thick crusts have higher Mg# than those from oceanic arcs with thin crusts. This is due to Fe depletion during high-pressure differentiation in thick crusts. Melting/crystallization experiments further support this hypothesis, showing that the Mg# characteristics of continental arc lavas match that of the continental crust. These findings suggest that the high Mg# of the continental crust can be explained by intracrustal calc-alkaline differentiation processes in magmatic orogens.
NATIONAL SCIENCE REVIEW
(2023)
Article
Geosciences, Multidisciplinary
Li-Juan Xu, Sheng-Ao Liu, Shuguang Li
Summary: Zinc isotopes can be used to track the recycling of crustal materials and the compositional heterogeneity of the mantle. The study on metabasalts from the Dabie Orogen in China showed variations in zinc isotopic compositions, indicating limited isotope fractionation during deep subduction processes.
GEOSCIENCE FRONTIERS
(2021)
Article
Geochemistry & Geophysics
Anupam Banerjee, Ramananda Chakrabarti, Antonio Simonetti
Summary: The study of stable Ca isotopic compositions of globally distributed carbonatites reveals that older carbonatites may be influenced by crustal carbonates in their mantle source, while younger carbonatites are likely affected by recycled crustal carbonates.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Long Chen, Dong-Yong Li, Jiang-Hong Deng, San-Zhong Li, Ian Somerville, Yi-Xiang Chen, Zi-Fu Zhao, Wei An, Xiao-Hui Li
Summary: Fe-Mg isotope data from mafic plutonic rocks and trench sediments in southern Tibet reveal negative correlations between d(26)Mg values and (Sr-87/Sr-86)(i) and (Pb-206/Pb-204)(i) values, but positive correlations with e(Nd)(t) and e(Hf)(t) values. Conversely, d(56)Fe values show positive correlations with (Sr-87/Sr-86)(i) and (Pb-206/Pb-204)(i) values, but negative correlations with e(Nd)(t) and e(Hf)(t) values. This suggests the importance of source mixing and source melting in the recycling of crustal materials in subduction zones.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geosciences, Multidisciplinary
Lei Yang, Jia-Min Wang, Xiao-Chi Liu, Gautam P. Khanal, Fu-Yuan Wu
Summary: The behavior of radiogenic isotopes during the melting of metasediments is influenced by the source and temperature of the melt. During the melting process, muscovite preferentially enters the melt relative to plagioclase, resulting in variation in Sr isotopes. In addition, the incomplete dissolution of zircon and the higher crystallization temperature result in the leucosome having Nd and Hf isotopes compositions closer to the source.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geochemistry & Geophysics
Tiago Valim Angelo, Christopher J. Spencer, Aaron J. Cavosie, Robert Thomas, Hong-Yan Li
Summary: Granitoids intruding oceanic crustal rocks and mantle peridotite in the Samail supra-subduction ophiolite of Oman and United Arab Emirates exhibit evolved chemical signatures. Tonalites and trondhjemites associated with oceanic crust display ridge 'tholeiitic' granitoid characteristics and are formed by basalt/gabbro fractionation or oceanic crust anatexis. Peraluminous mantle-hosted granitoids, on the other hand, show compositional differences from typical S-type granitoids, suggesting a distinct tectonic setting involving the subducted slab and minimal mantle contribution.
JOURNAL OF PETROLOGY
(2023)
Article
Geochemistry & Geophysics
Qi-Qi Pan, Yan Xiao, Ben-Xun Su, Xia Liu, Paul T. Robinson, Ibrahim Uysal, Peng-Fei Zhang, Patrick Asamoah Sakyi
Summary: Amphibole occurrences in chromitites, dunites, and harzburgites from the Lycian ophiolite in Turkey provide evidence for water involvement in chromitite formation and metasomatism. The composition and crystallization temperatures of interstitial amphibole and amphibole inclusions in chromite suggest the presence of hydrous melts/fluids during the initial subduction of the Neo-Tethyan oceanic lithosphere.
AMERICAN MINERALOGIST
(2022)
Article
Geosciences, Multidisciplinary
Orhan Karsli, Firat Sengun, Jose Francisco Santos, Ibrahim Uysal, Abdurrahman Dokuz, Faruk Aydin, Raif Kandemir
Summary: This study provides new insights into the Late Jurassic granitic magmatism in the Sakarya Zone in northwestern Turkey. The granitic rocks were likely formed by low degree melting of the eclogitic part of an oceanic slab, followed by magma fractionation and crustal contamination. The findings suggest that the continental back-arc basin system played a significant role in the Late Jurassic tectonic evolution of the Paleotethys Ocean and the western Sakarya Zone.
Article
Geochemistry & Geophysics
Leah E. E. Morgan, Brett Davidheiser-Kroll, Klaudia F. F. Kuiper, Darren F. F. Mark, Noah M. M. McLean, Jan R. R. Wijbrans
Summary: The accuracy and traceability of geochronometers are crucial to questions asked by Earth scientists. This study focuses on the 40Ar/39Ar geochronometer and its co-irradiation with reference materials. The authors used various calibration methods to determine the ages of monitor minerals and found that the current results do not meet the desired accuracy, but the extensive methodology development presented in this study can help improve future measurements.
GEOSTANDARDS AND GEOANALYTICAL RESEARCH
(2023)
Article
Geochemistry & Geophysics
Xia Liu, Ben-Xun Su, Phillip Gopon, Yan Xiao, Ibrahim Uysal
Summary: Compared to magmatic processes, the modification of chromite by low-temperature hydrothermal activities in ophiolites has been less studied. In this study, chromitites from the Bursa ophiolite in NW Turkey were found to be modified by hydrothermal fluids, resulting in the presence of unusual inclusions and intergrowths of magnesite, quartz, chlorite, and ferrian chromite. The infiltration of reducing and SiO2-rich serpentinizing fluids caused changes in the composition of ferrian chromite, while CO2-rich fluids led to carbonation of the serpentine matrix and the formation of interstitial magnesite and quartz. The carbon and oxygen isotope compositions of magnesite indicated that the CO2-rich fluids were derived from decarbonation of local marble and metaclastic rocks.
Review
Geosciences, Multidisciplinary
Hossein Azizi, Robert J. Stern, Raif Kandemir, Orhan Karsli
Summary: The Early to Middle Jurassic stratigraphic sequences of the Sanandaj-Sirjan Zone in Iran and the Sakarya Zone in Turkey, which exhibit similar features, suggest that they formed in a common tectonic setting of an extensional basin. The whole-rock chemistry and Sr-Nd isotope signatures indicate that the mafic melts originated from partial melting of the subcontinental lithosphere. The decompression associated with extension led to the partial melting of spinel-garnet lherzolite and formation of tholeiitic to transitional basaltic magma. The inversion of extensional basins occurred during the Mid-Late Jurassic.
Article
Geosciences, Multidisciplinary
Ferkan Sipahi, Mehmet Ali Gucer, Abdurrahman Dokuz, Keewook Yi, Abdullah Kaygusuz, Enver Akaryali, Cigdem Saydam Eker, Cuneyt Doruk
Summary: In this study, geochronological and geochemical data from the Dagdibi Pluton in the Sakarya Zone were obtained to understand the source region and petrogenesis of the middle Eocene magmatism. The pluton has been dated to around 45 million years ago and is primarily composed of K-feldspar, plagioclase, quartz, Mg-hornblende/actinolite, Fe-Ti oxides, and small amounts of biotite. The geochemical and isotopic characteristics of the pluton suggest that it originated from a depleted mantle that was metasomatized by fluids during previous subduction events.
GEOLOGICAL MAGAZINE
(2023)
Article
Geology
Yalcin E. Ersoy, Ibrahim Uysal, Osman Candan, Martin R. R. Palmer, Dirk Mueller
Summary: In eastern Anatolia, the Divrigi-Hekimhan Magmatic Province (DHMP) consists of alkaline rock units formed 77-69 million years ago, located to the northwest of the Baskil Arc formed 85-74 million years ago. These rocks are composed of different types, including basaltic, trachytic, and syenitic rocks, with varying mineral compositions. Geochemical analysis indicates that the magmas originated from a shallow asthenospheric mantle source, which had undergone metasomatism due to subduction processes.
INTERNATIONAL GEOLOGY REVIEW
(2023)
Article
Geosciences, Multidisciplinary
Abdurrahman Dokuz, Mehmet Cihat Alcicek, Vahdet Tuncdemir, Raif Kandemir, Emre Aydincakir
Summary: The processes of removal of sediments in the eastern Sakarya Zone, Turkey, from the upper Carboniferous to Permian period were modeled using geochemical data and LA-ICP-MS U-Pb ages from detrital zircons. The geochemistry and ages indicate a felsic provenance and passive margin setting during the deposition of the upper Carboniferous sediments, as well as subduction-related tectonic setting and increasing erosion rate during the deposition of the overlying Hardisi Formation. The deposition of catalcesme sediments in a back-arc basin, separated from Gondwana, and their subsequent migration into a lacustrine setting are highlighted.
JOURNAL OF ASIAN EARTH SCIENCES
(2023)
Article
Geochemistry & Geophysics
Simge Oguz-Saka, Faruk Aydin, Orhan Karsli, Abdurrahman Dokuz, Thomas Aiglsperger, Daniel P. Miggins, Cuneyt Sen, Raif Kandemir, Bilal Sari, Anthony A. P. Koppers
Summary: The eastern Blacksea magmatic arc (EBMA) in the eastern Sakarya Zone (ESZ) provides a valuable opportunity to study the birth of an extensional intra-arc and back-arc settings during the Late Cretaceous. The volcanic activity of the EBMA during the Late Cretaceous occurred in two major phases, characterized by a bimodal distribution of rock types. The geochemical and isotopic data suggest that the volcanic rocks in the EBMA were formed through interactions with mantle metasomatized by slab/sediment-derived fluids and lower crustal materials.
Article
Geochemistry & Geophysics
Orhan Karsli, Firat Sengun, Faruk Aydin, Hadi S. Moghadam, Abdurrahman Dokuz, William L. Griffin, Simge Oguz Saka, Thomas Zack
Summary: Turkey's Early Paleozoic tectonic evolution has been the focus of attention. Early Paleozoic intrusive rocks are mainly distributed across Europe, Turkey, and Iran. However, the Early Paleozoic rocks have not yet been identified in north Turkey's Sakarya Zone, and thus the Early Paleozoic paleogeography of the Sakarya Zone remains enigmatic. This study provides new field observations, petrography, geochemistry, and geochronology to identify the nature, origin, and tectonic setting of the Ordovician magmatic rocks in the So center dot gut area (Bilecik, northwest Turkey) in the western Sakarya Zone.
Article
Geochemistry & Geophysics
B. Petri, J. R. Wijbrans, G. Mohn, G. Manatschal, M. Beltrando
Summary: The thermal evolution of the Austroalpine Campo and Grosina units, which were part of the necking zone of the Adriatic rifted margin, were studied. The two units exhibited different thermal histories, with the Grosina unit undergoing a slow cooling process during the Permo-Triassic period and the Campo unit experiencing a rapid cooling process during the Jurassic rifting. These findings provide insights into the tectonic evolution and thermal subsidence of the region.
Article
Geosciences, Multidisciplinary
Ben-Xun Su, Qi-Qi Pan, Yan Xiao, Jie-Jun Jing, Paul T. Robinson, Ibrahim Uysal, Xia Liu, Jian-Guo Liu
Summary: The traditional interpretation of mantle peridotites in ophiolites needs to be reconsidered as recent petrological and geochemical data suggest significant compositional variations and modifications in these rocks. The presence of interstitial spinel grains and widespread clinopyroxene suggests post-crystallization modifications. Amphibole and enriched Mg and Ca melts/fluids serve as evidence of the past presence of hydrous melts and indicate interactions between different lithologies. The mantle peridotites of ophiolites cannot be considered as paleo-oceanic lithospheric mantle and cannot be used for reconstructing ancient oceans or constraining global tectonic processes.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geosciences, Multidisciplinary
Igor K. Nikogosian, Antoine J. J. Bracco Gartner, Paul R. D. Mason, Douwe J. J. van Hinsbergen, Klaudia F. Kuiper, Uwe Kirscher, Sergei Matveev, Araik Grigoryan, Edmond Grigoryan, Arsen Israyelyan, Manfred J. van Bergen, Janne M. Koornneef, Jan R. Wijbrans, Gareth R. Davies, Khachatur Meliksetian
Summary: This study presents new geochronological, palaeomagnetic, and geochemical constraints to understand the geodynamic evolution of the South Armenian Block (SAB) and its Gondwanan origin. It reveals the timing of rifting and provides insights into the geological history of the SAB since the Permian.
Article
Environmental Sciences
Yanpu Zhao, Jan R. Wijbrans, Hua Wang, Pieter Z. Vroon, Jianghao Ma, Yanqiong Zhao
Summary: Hydrochemistry and strontium isotope data were analyzed to study the variations in chemical weathering and CO2 consumption fluxes in the Xi River Drainage system. The main ions were Ca2+, Mg2+, and HCO3-, indicating a drainage system on carbonate-dominated bedrock. The weathering rates of silicate and carbonate increased downstream, while the carbonate weathering rates peaked in the middle reaches. Chemical weathering variations were mainly controlled by lithology, vegetation, and climate factors. The Xi River Basin is a CO2 sink with a net consumption of CO2 flux.
INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH
(2023)