S. Oriolo, P. González, Pablo Alegre, K. Wemmer, R. Varela, M. Basei
{"title":"The Cuesta de Rahue Basement Inlier (Southern Neuquén Precordillera, Argentina): A Devonian to Triassic polyphase orogenic record in northern Patagonia","authors":"S. Oriolo, P. González, Pablo Alegre, K. Wemmer, R. Varela, M. Basei","doi":"10.1144/jgs2022-143","DOIUrl":"https://doi.org/10.1144/jgs2022-143","url":null,"abstract":"New geological, structural, microstructural, and K-Ar biotite and illite geochronological data of igneous-metamorphic rocks exposed in the Cuesta de Rahue Basement Inlier are presented to reconstruct the Late Palaeozoic to Mesozoic tectonometamorphic and magmatic history of northwestern Patagonia. This block comprises a medium-grade metasedimentary sequence (Cuesta de Rahue Metamorphic Complex), Late Carboniferous granitoids and a low-grade metavolcano-sedimentary unit (Arroyo Coloco Metamorphic Complex). The Cuesta de Rahue Metamorphic Complex was deposited during the middle Palaeozoic and underwent Devonian low-pressure regional metamorphism, succeeded by the intrusion of granitoids at ca. 300 Ma. On the other hand, the Arroyo Coloco Metamorphic Complex record deformation and metamorphism at epizonal conditions (> 300 °C), constrained at ca. 232-199 Ma by K-Ar and XRD illite data. The Cuesta de Rahue Basement Inlier thus records a protracted orogenic evolution, recording Devonian metamorphism, Late Carboniferous-Permian Gondwanide tectonomagmatic processes, and Late Triassic deformation and metamorphism. Afterwards, this block was also affected by Mesozoic normal faulting and, finally, by Miocene-Pliocene Andean deformation. The latter was intimately related to reactivation of inherited basement fabrics, favouring a transpressional deformation regime.\u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.6484467\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48698650","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Naing, S. Robinson, M. Searle, C. Morley, I. Millar, O. Green, P. Bown, T. Danelian, M. Petrizzo, G. Henderson
{"title":"Age, depositional history and tectonics of the Indo-Myanmar Ranges, Myanmar","authors":"T. Naing, S. Robinson, M. Searle, C. Morley, I. Millar, O. Green, P. Bown, T. Danelian, M. Petrizzo, G. Henderson","doi":"10.1144/jgs2022-091","DOIUrl":"https://doi.org/10.1144/jgs2022-091","url":null,"abstract":"The Indo-Myanmar Ranges (IMR) are an enigmatic mountain belt that occupy a complex tectonic zone in western Myanmar extending from the northern continuation of the active Sunda-Andaman arc into the eastern Himalayan syntaxis. The IMR are part of an accretionary fore-arc basin-arc complex that includes the Central Myanmar Basin and the Wuntho-Popa Arc to the east. New biostratigraphic, petrologic, and detrital zircon U-Pb age data are presented that are used to test and refine the divergent tectonic models that have been proposed for western Myanmar. These data suggest: 1) that the Upper Triassic Pane Chaung Formation was originally deposited adjacent to the NE Indian continental margin within northern Gondwana during the Late Triassic, and 2) that the Upper Cretaceous – Paleogene rocks of the IBR were mainly derived from the Wuntho-Popa Arc and Inner Belt, with a subordinate input from a crustal source, potentially from the Naga metamorphic-type Paleozoic basement. The Kalemyo ophiolite has an Early Cretaceous age similar to ages of ophiolites in the Indus Yarlung-Tsangpo suture zone, south Tibet and Nagaland, reinforcing the hypothesis that they were once part of the same Neo-Tethyan ocean floor.\u0000 \u0000 Supplementary material:\u0000 https://doi.org/10.6084/m9.figshare.c.6487105\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46546298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Volkan Karabacak, Ç. Özkaymak, H. Sözbilir, O. Tatar, B. Aktuğ, Ö. Özdağ, R. Çakır, E. Aksoy, Fikret Koçbulut, Mustafa Softa, Elif Akgün, Ahmet Demir, Gökhan Arslan
{"title":"The 2023 Pazarcık (Kahramanmaraş, Türkiye) Earthquake (Mw: 7.7): Implications for surface rupture dynamics along the East Anatolian Fault Zone","authors":"Volkan Karabacak, Ç. Özkaymak, H. Sözbilir, O. Tatar, B. Aktuğ, Ö. Özdağ, R. Çakır, E. Aksoy, Fikret Koçbulut, Mustafa Softa, Elif Akgün, Ahmet Demir, Gökhan Arslan","doi":"10.1144/jgs2023-020","DOIUrl":"https://doi.org/10.1144/jgs2023-020","url":null,"abstract":"\u0000 Southern Türkiye faced widespread catastrophic destruction by two devastating earthquakes on the same day. As the earthquakes occurred at 04:17 (Mw=7.7, Pazarcık, Kahramanmaraş) and 12:30 (Mw=7.6, Elbistan, Kahramanmaraş) on February 6, 2023, neighboring active fault systems were broken in succession between the Hatay and Malatya Provinces in the region. The first earthquake, one of the largest earthquakes in this region during the last century, caused widespread damage to infrastructure and buildings, and produced large scale seismo-gravitational surface deformation such as landslides, lateral spreading, liquefaction and also extensional cracks. Here, we present the surface rupture geometry and coseismic displacement characteristics of the fault systems, determined with field observations immediately after the February 6, 2023 Pazarcık (Kahramanmaraş, Türkiye) earthquake (Mw=7.7). Preliminary results show that the total rupture length (L\u0000 max\u0000 ) is 270±10 km on the Karasu, Pazarcık and Erkenek segments of the East Anatolia Fault Zone. Left-lateral strike-slip faulting is developed with a maximum horizontal displacement (D\u0000 max\u0000 ) of 7.30 m and an average displacement (D\u0000 avg\u0000 ) of 3.00 m. Although the surface rupture generally exhibits a narrow deformation zone width of 2-5 m, it expands up to 50 m in some sections of the faults. Our implications for rupture dynamics suggest that fracture development started on a secondary fault (Narlı Fault), transferred to the main fault and triggered the breaking of asperities on Pazarcık segment which exhibits a long period accumulation of stress to initiate the major rupturing.\u0000 \u0000 \u0000 Supplementary material:\u0000 Figures S1 – S12 with details on coseismic displacement are available at:\u0000 https://doi.org/10.6084/m9.figshare.c.6487245\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-03-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47086340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bing Pan, Malik Muhammad Saud Sajid Khan, Guoxiang Li, Shehryar Ahmed, M. Qasim, Z. Yin, I. A. Jadoon, Maoyan Zhu
{"title":"Occurrence of\u0000 Tannuolina\u0000 in the early Cambrian siltstones of Hazara Basin, North Pakistan and its biostratigraphical significance","authors":"Bing Pan, Malik Muhammad Saud Sajid Khan, Guoxiang Li, Shehryar Ahmed, M. Qasim, Z. Yin, I. A. Jadoon, Maoyan Zhu","doi":"10.1144/jgs2021-149","DOIUrl":"https://doi.org/10.1144/jgs2021-149","url":null,"abstract":"\u0000 The tommotiids are an important group of Cambrian small shelly fossils, primarily retrieved from the carbonate rock by acid process. Herein, the abundant isolated sclerites of\u0000 Tannuolina\u0000 are recovered from the siltstone-dominated upper part of the Hazira Formation in the eastern Hazara Basin, North Pakistan. This discovery of tommotiids preserved in the siltstones not only suggests their occurrences in a variety of sedimentary lithofacies, but also provides the opportunity to look for the sclerites or scleritomes (even soft-tissue) of tommotiids in much wider taphonomic windows. The sclerites include two morphs, i.e. mitral and sellate types. Through morphological comparison, they can be identified as\u0000 Tannuolina zhangwentangi\u0000 Qian & Bengtson, 1989. The large mitral and sellate sclerites (about 1 cm) illustrated herein manifest a relatively consistent morphology during the size increasement. The sellate sclerites may contain two sub-types, the larger sellate sclerite with sella on the sellate side and the smaller convex sellate side without sella on either sides. In the original scleritome, the two sub-types of sellate sclerites probably combine as a composite with the duplicatural side of the smaller one attached on the sella area of the large one. For the first time,\u0000 T. zhangwentangi\u0000 has been recovered from the Indian subcontinent, previously unknown outside South China. The middle and upper part of the Hazira Formation exclusively bearing\u0000 T. zhangwentangi\u0000 can directly invite correlation with the\u0000 S. flabelliformis\u0000 –\u0000 T. zhangwentangi\u0000 Assemblage Zone of South China representing the uppermost Cambrian Stage 2. This new palaeontological finds not only signifies the utility of\u0000 T. zhangwentangi\u0000 for intercontinental biostratigraphical correlation, but also suggests that the Terreneuvian SSF biostratigraphy between the Indian subcontinent and South China are quite consistent, comprising of three (at least two) correlative SSF Assemblage Zone (Zone Ⅰ, possible Ⅲ, and Ⅳ of South China). Additionally, our result may also support a relatively close palaeogeographical linkage between these two regions in early Cambrian.\u0000 \u0000 \u0000 Thematic collection:\u0000 This article is part of the Advances in the Cambrian Explosion collection available at:\u0000 https://www.lyellcollection.org/topic/collections/advances-in-the-cambrian-explosion\u0000","PeriodicalId":17320,"journal":{"name":"Journal of the Geological Society","volume":" ","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42217934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}