Article
Geochemistry & Geophysics
Camille Dusseaux, Aude Gebelin, Gilles Ruffet, Andreas Mulch
Summary: The study presents the first stable isotope paleoaltimetry estimates for the hinterland of the eroded Variscan Belt of Western Europe based on hydrogen isotope ratios of muscovite from syntectonic leucogranites. The significant difference in hydrogen isotope values between the Millevaches massif and the Bourbon l'Archambault foreland basin supports paleoaltimetry estimates, indicating that the Variscan belt of western Europe acted as a barrier to moisture transport and induced an orographic rain shadow effect.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Herve Rezeau, Marc Hassig, Emin Sadikhov, Massimo Chiaradia, Robert Moritz
Summary: The present-day configuration of the Lesser Caucasus and Eastern Pontides regions has been shaped by multiple episodes of arc magmatism and tectonic events. These regions are also rich in mineral deposits, such as polymetallic deposits and porphyry Cu-Mo deposits. New zircon Hf isotopic data has provided insights into the geological evolution of these areas, highlighting three distinct cycles of arc magmatism and revealing the presence of a composite basement. This study offers new constraints for understanding the geodynamic evolution of the region and provides valuable information for mineral exploration.
EARTH-SCIENCE REVIEWS
(2023)
Review
Geosciences, Multidisciplinary
Boheng Shen, Shuzhong Shen, Qiong Wu, Shuichang Zhang, Bin Zhang, Xiangdong Wang, Zhangshuai Hou, Dongxun Yuan, Yichun Zhang, Feng Liu, Jun Liu, Hua Zhang, Yukun Shi, Jun Wang, Zhuo Feng
Summary: This study critically reviews the chronostratigraphy and biostratigraphy of the latest Carboniferous and Permian in the North China Block and provides insights into the stratigraphic correlation and geological events. The study also estimates the amplitude of sea-level changes and highlights the favorable period for coal accumulation during the late Carboniferous and early Permian. The climatic shift during the Permian is attributed to the northward migration of the Pangea and the closure of the Paleo Asian Ocean.
SCIENCE CHINA-EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Yukun Shi, Xiangdong Wang, Junxuan Fan, Hao Huang, Huiqing Xu, Yingying Zhao, Shuzhong Shen
Summary: Recent study revealed a rapid increase of marine fauna species and genus richness during the Late Paleozoic Ice Age, lasting 41.2 million years and named as Carboniferous-earliest Permian Biodiversification Event (CPBE). The event included a slow increase episode and a main radiation episode, with most distinct patterns in fusulinid foraminifera and decreasing trends in nektonic conodonts and cephalopods, possibly related to marine environmental shifts caused by the Rheic Ocean closure.
EARTH-SCIENCE REVIEWS
(2021)
Article
Geography, Physical
Yuan Wang, Jianghai Yang, Charles M. Henderson, Dongxun Yuan, Rui Ma, Jia Liu
Summary: This study establishes five conodont zones for the Taiyuan Formation in southern North China and determines a late Gzhelian to late Asselian age, which is consistent with high-precision zircon U-Pb ages. The study also combines conodont biostratigraphy with previously published U-Pb ages to construct a new chronostratigraphic framework for the Carboniferous-Permian strata across North China. It reveals an earlier initiation of climate aridification in the northern part compared to the southern part, possibly due to northward drift, increased atmospheric pCO2, and global warming.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2023)
Article
Thermodynamics
Kai Wang, Tao Han, Jun Deng, Yanni Zhang
Summary: The study investigates the coal combustion characteristics and kinetic parameters of Chinese coals from different geological periods. The results show that the heating rate has an impact on the characteristic temperatures of coal samples. The Carboniferous-Permian coals have lower ignition temperatures, higher heat release, and lower activation energy compared to Jurassic coals, indicating superior combustion performance.
Article
Geosciences, Multidisciplinary
Donghai Zhang, Baochun Huang, Guochun Zhao, Joseph G. Meert, Simon Williams, Jie Zhao, Tinghong Zhou
Summary: Research indicates that the northward motion of North China and Mongolia paralleled Laurussia from the Late Carboniferous to Early Permian, with the Paleo-Asian Ocean in the east-central segment having a width of about 2,700 km. This wide ocean impeded floral and faunal exchange until the Guadalupian, prior to its final closure by approximately 250 Ma.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geography, Physical
Joan Lloret, Jose Lopez-Gomez, Nemesio Heredia, Fidel Martin-Gonzalez, Raul de la Horra, Violeta Borruel-Abadia, Ausonio Ronchi, Jose F. Barrenechea, Joaquin Garcia-Sansegundo, Carlos Gale, Teresa Ubide, Nicola Gretter, Jose B. Diez, Manuel Juncal, Marceliano Lago
Summary: This study integrates detailed stratigraphic, sedimentary, tectonic, paleosol, and magmatic data to reveal a similar geodynamic evolution across the Pyrenean-Cantabrian Ranges at the end of the Variscan cycle. The lower-middle Permian basins started their development under an extensional regime related to the end of the Variscan Belt collapse, transitioning to Pangea breakup in the middle Permian times. The comparison with other basins near the paleoequator shows common features of magmatic activity, extensional tectonics, high subsidence rates, thick sedimentary records, and periods without sedimentation, providing a better understanding of major crustal re-equilibration and reorganization in Western-Central Europe during the post-Variscan period.
GLOBAL AND PLANETARY CHANGE
(2021)
Article
Geosciences, Multidisciplinary
J. Deckers, B. Rombaut
Summary: During the Westphalian C period, the southeastern Campine Basin was part of the foreland of the Variscan Orogen, where sedimentation and subsidence led to thinning of rock units towards the northwest due to flexural downwarping of the continental crust, likely caused by tectonic loading from the approaching Variscan Orogen. This asymmetric subsidence pattern reflects a foreland system with a forebulge flank extending into the Campine Basin, consistent with existing data and models in the region.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2021)
Article
Geochemistry & Geophysics
Manuel Francisco Pereira, Jose Manuel Fuenlabrada, Carmen Rodriguez, Antonio Castro
Summary: Carboniferous magmatism in southwestern Iberia played a crucial role in understanding the formation of the Pangea supercontinent and recorded the complex oblique convergence between Laurussia and Gondwana. A new tectonic model suggests that the Iberia Variscan belt was the site of simultaneous collisional and accretionary orogenic processes.
Article
Geosciences, Multidisciplinary
Kevin Freville, Pierre Trap, Jonas Vanardois, Jeremie Melleton, Michel Faure, Olivier Bruguier, Marc Poujol, Philippe Lach
Summary: This study provides a reappraisal of the Variscan tectono-metamorphic history of the Pelvoux Massif, proposing a new understanding of the flow pattern and kinematics of the Variscan crust and the Eastern Variscan Shear Zone. The results suggest a sinistral transpression and NW-SE shortening event, with the onset of crustal partial melting around 650 degrees C during the late Visean. The findings also indicate strain partitioning and horizontal crustal flow, as well as the southeastward motion of the partially molten crust.
BSGF-EARTH SCIENCES BULLETIN
(2022)
Article
Geochemistry & Geophysics
Jaime A. Poblete, Paul H. G. M. Dirks, Zhaoshan Chang, Jan Marten Huizenga, Martin Griessmann, Chris Hall
Summary: The Watershed tungsten deposit in the Mossman orogen is largely found in skarn-altered conglomerate, influenced by four deformation events that led to the formation of multistage quartz veins. Key controls on scheelite mineralization include early monzonite dikes enriched in scheelite, D-4 shear zones acting as fluid conduits, skarn-altered conglomerate providing a host for vein formation, and an extensional depositional environment.
Article
Geosciences, Multidisciplinary
Renda Huang, Fujie Jiang, Di Chen, Ruoyuan Qiu, Tao Hu, Linhao Fang, Meiling Hu, Guanyun Wu, Chenxi Zhang, Jiahao Lv, Yuping Wu, Liliang Huang
Summary: By studying the Fengcheng Formation in northwest China, we have confirmed that it records the Carboniferous-Permian boundary. Through global carbon isotope data, we found the similarity of negative carbon isotope excursions in terrestrial and marine profiles, supporting their global synchrony and potential use for delimiting the Carboniferous-Permian boundary in terrestrial sections. This study contributes to understanding the Carboniferous-Permian global carbon cycle, high-latitude glaciation, eustatic fluctuations, global volcanism, and their potential relationships.
Article
Geology
Jean-Baptiste Jacob, Stephane Guillot, Daniela Rubatto, Emilie Janots, Jeremie Melleton, Michel Faure
Summary: The study confirms the age of Variscan high-pressure metamorphism in the Palaeozoic basement of the western Alps, with ages of 456 ± 4 Ma and 448 ± 6 Ma obtained from eclogites. The peak pressure stage in the retrogressed eclogites was estimated to be >1.4 GPa at 690-740 degrees C, followed by decompression. Metamorphic zircon rims yield U-Pb dates scattering between 340 and 310 Ma, representing late stages of melt crystallization. The development of a mylonitic S2 foliation correlates with retrogression in the amphibolite facies during the mid-late Carboniferous, indicating exhumation of eclogites mixed with mid-crustal felsic lithologies.
JOURNAL OF METAMORPHIC GEOLOGY
(2021)
Article
Geography, Physical
Leifu Zhang, Dazhong Dong, Zhen Qiu, Chenjun Wu, Qin Zhang, Yuman Wang, Dexun Liu, Ze Deng, Shangwen Zhou, Songqi Pan
Summary: The study of the marine-continental transitional strata in the Upper Carboniferous to Lower Permian through high-resolution geochemical data integration reveals the characteristics of frequent sedimentary environment changes and the accumulation of organic-rich sediment under varied conditions.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2021)
Article
Geology
Remziye Akdogan, Istvan Dunkl, Aral I. Okay, Xiumian Hu, Gultekin Topuz
Summary: Apatite fission-track and (U-Th)/He ages from Carboniferous to Eocene siliciclastic rocks in the Istanbul Zone of NW Turkey suggest three major deformation and uplift/exhumation phases. These phases are attributed to orogeny, accretion of oceanic plateaus, and closure of oceanic domains in the region.
INTERNATIONAL GEOLOGY REVIEW
(2022)
Article
Geosciences, Multidisciplinary
Umitcan Erbil, Aral Okay, Aynur Hakyemez
Summary: Late Cenozoic in the Aegean region was characterized by large-scale extension, except for the Thrace Basin which showed continuous marine sedimentation from Middle Eocene to Oligocene. The Korudag anticline in the Thrace Basin, formed by north-northwest shortening, is an asymmetric fold with a subhorizontal axis and is unconformably overlain by Middle Miocene sandstones. This shortening event in the Late Oligocene-Early Miocene might be related to changes in subduction dynamics along the Hellenic trench.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2021)
Article
Geochemistry & Geophysics
Seungsoon Choi, Olivier Fabbri, Gultekin Topuz, Aral Okay, Haemyeong Jung
Summary: This study examined the impact of twinning on crystal preferred orientation, CPO strength, and seismic anisotropy in lawsonite blueschists, finding that the presence of twins can significantly reduce seismic anisotropy.
Article
Geosciences, Multidisciplinary
Mesut Aygul, Aral Okay, Bradley R. Hacker, Andrew R. C. Kylander-Clark
Summary: In situ laser probing of minerals in lawsonite-bearing eclogites and a metabasite provides insights into the redistribution and mobility of REEs controlled by metamorphic reactions. The study reveals significant HREE depletion in garnets due to the nucleation of lawsonite, and enrichment of MREE caused by the breakdown of lawsonite in epidote-bearing eclogites. These findings suggest that the behavior of REEs are influenced by different factors in warm and cold subduction zones.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2022)
Article
Geosciences, Multidisciplinary
Aral Okay, Demir Altiner, Taniel Danelian, Gultekin Topuz, Ercan Ozcan, Andrew R. C. Kylander-Clark
Summary: Ophiolitic melanges in Anatolia are Mesozoic subduction-accretion complexes with a scarcity of land-derived coarse-clastic rocks. Through the study of a segment in the Beynam region, it was found that the ophiolitic melange consists of three accretionary units, formed in two stages. The first stage, in the Late Jurassic - Early Cretaceous, involved intra-oceanic subduction and the generation of supra-subduction type oceanic crust. The second stage, in the Late Cretaceous, led to the incorporation of Jurassic oceanic crust into the subduction-accretion complex and the formation of an Andean-type convergent margin.
GEOLOGICAL MAGAZINE
(2022)
Editorial Material
Geochemistry & Geophysics
Aral I. Okay
Article
Geosciences, Multidisciplinary
Aral I. Okay, Andrew R. C. Kylander-Clark
Summary: Detrital zircon ages from Upper Cretaceous sandstones in the Pontides and Anatolide-Tauride Block reveal differences in zircon compositions between the two regions. The absence of sediment transport between the two blocks during the latest Cretaceous suggests an earlier deformation event in the Bornova Flysch Zone related to ophiolite obduction. The predominance of Carboniferous detrital zircons highlights the significance of Carboniferous magmatic activity in the Anatolide-Tauride Block.
INTERNATIONAL JOURNAL OF EARTH SCIENCES
(2023)
Article
Geology
Donna L. Whitney, Jonathan R. Delph, Stuart N. Thomson, Susan L. Beck, Gilles Y. Brocard, Michael A. Cosca, Michael H. Darin, Nuretdin Kaymakci, Maud J. M. Meijers, Aral I. Okay, Bora Rojay, Christian Teyssier, Paul J. Umhoefer
Summary: Escape tectonics is a mechanism for the formation of new plates, in which lithospheric fragments move laterally along strike-slip faults in response to collision. Analysis of thermochronology data and seismic images near the East Anatolian fault zone provides insights into the development of the Anatolian plate and escape system. The younger ages of rocks in and near the EAFZ, as well as the presence of strong Arabian lithospheric mantle beneath the Anatolian crust, suggest that thermal activity and underthrusting of Arabian lithosphere played a fundamental role in the formation of the Anatolian plate and escape system.
Article
Geology
Cumhur Babaoglu, Gultekin Topuz, Aral I. Okay, Serhat Koksal, Jia-Min Wang, Fatma Toksoy-Koksal
Summary: This paper investigates the petrology and age of the volcanism in the Istanbul Zone, NW Turkey. It discovers minor alkaline basalt and acidic volcanic rocks that date back to approximately 261 million years ago. It suggests that the volcanism occurred in an extensional setting concurrent with the northward subduction of the Palaeo-Tethys beneath the Sakarya and Istanbul zones after the Variscan orogeny.
INTERNATIONAL GEOLOGY REVIEW
(2023)
Article
Geology
Ezgi Saglam, Turgut Duzman, Cemre Ay, Aral I. Okay, Gultekin Topuz, Gursel Sunal, Ercan Ozcan, Demir Altiner, Aynur Hakyemez, Jia-Min Wang, Andrew R. C. Kylander-Clark
Summary: During the Late Cretaceous, a 2700 km-long magmatic arc extended from the Lesser Caucasus through the northern margin of the Pontides into ABTS in the Balkans. The arc magmatism started in the Turonian, peaked in the middle Campanian, and became rare after the late Campanian. The magmatism showed calc-alkaline to high-K calc-alkaline composition and subduction geochemical signatures.
INTERNATIONAL GEOLOGY REVIEW
(2023)
Article
Geochemistry & Geophysics
Aral I. Okay, Ercan Ozcan, Muzaffer Siyako, Kerem A. Burkan, Andrew R. C. Kylander-Clark, Michael D. Bidgood, David Shaw, Michael D. Simmons
Summary: The Thrace Basin, with its complex tectonic history, is a challenging case for classification. New geochronological and biostratigraphic data provide insights into its tectonic evolution, revealing that the basin primarily contains early Oligocene siliciclastic turbidites sourced from the Rhodope Complex. The exhumation of the northern Rhodope Complex coincided with the main subsidence in the Thrace Basin, suggesting a connection between crustal rotation and basin development.
Article
Geosciences, Multidisciplinary
Ali Osman Yucel, Ercan Ozcan, Rita Catanzariti, Aynur Hakyemez, Aral I. Okay, Attila Ciner, Ali Akin
Summary: New field observations and discovery of calcareous nannofossils and planktonic foraminifera in the shallow-marine Cayraz Formation in Haymana Basin, Central Anatolia, allows for the revision of its stratigraphy and the establishment of a biostratigraphic scheme. Calcareous nannofossils in the upper part of the underlying Eskipolatli Formation suggest the initiation of the Cayraz shelf system in the middle Ypresian, while marly parts of the Cayraz Formation indicate Zone CNE6 in the late Ypresian. Hemipelagic marls in the upper part of the formation yield calcareous nannofossils indicating Zone CNE9 and CNE10 in the lower samples, and Zone CNE12 in the upper samples. The same beds also yield planktonic foraminifers indicating Zone E8 and E9. The end of shallow-marine sedimentation in the Cayraz section is proposed to be in the middle Lutetian.
TURKISH JOURNAL OF EARTH SCIENCES
(2023)
Article
Geology
Donna L. Whitney, Jonathan R. Delph, Stuart N. Thomson, Susan L. Beck, Gilles Y. Brocard, Michael A. Cosca, Michael H. Darin, Nuretdin Kaymakci, Maud J. M. Meijers, Aral I. Okay, Bora Rojay, Christian Teyssier, Paul J. Umhoefer
Summary: This study provides insights into the development of the new plate and escape system by using thermochronology data and seismic images. It is found that the rocks near the East Anatolian fault zone are significantly younger, indicating thermal activity triggered by strike-slip faulting. The images also reveal that the underthrusting of the strong Arabian lithosphere played a crucial role in the localization of the fault zone and the formation of the Anatolian plate and escape system.
Article
Paleontology
Ercan Ozcan, Ali Osman Yucel, Simon F. Mitchell, Johannes Pignatti, Michael D. Simmons, Aral Okay, Levent Sina Erkizan, Munire Nur Gultekin
Summary: This article introduces a unique combination of carbonate-clastic and larger benthic foraminifera in the middle to upper Eocene of northwest Turkey, and describes a newly discovered genus of larger benthic foraminifera, Caudriella. The study reveals the distribution of Caudriella in both the Caribbean and Western Neo-Tethys regions. Comparative analysis of the embryonic-nepionic stages of Caudriella and the emendation of its diagnosis are also conducted.
JOURNAL OF FORAMINIFERAL RESEARCH
(2022)