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Ransiki earthquakes, northeastern Bird’s Head Peninsula, northwestern New Guinea, Indonesia: Deformation partitioning in oblique plate convergence 印度尼西亚新几内亚西北部鸟头半岛东北部Ransiki地震:斜板块会聚中的变形划分
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-12-01 Epub Date: 2023-09-23 DOI: 10.1016/j.jog.2023.101999
Sukahar Eka Adi Saputra , Christopher L. Fergusson , Colin V. Murray-Wallace
{"title":"Ransiki earthquakes, northeastern Bird’s Head Peninsula, northwestern New Guinea, Indonesia: Deformation partitioning in oblique plate convergence","authors":"Sukahar Eka Adi Saputra ,&nbsp;Christopher L. Fergusson ,&nbsp;Colin V. Murray-Wallace","doi":"10.1016/j.jog.2023.101999","DOIUrl":"https://doi.org/10.1016/j.jog.2023.101999","url":null,"abstract":"<div><p>The plate boundary between the Pacific-Caroline and Australian plates in northwestern New Guinea is associated with a geographic concentration of earthquakes developed in the Ransiki region of the northeastern Bird’s Head Peninsula (West Papua, northwestern New Guinea) at the intersection of the Ransiki and Yapen faults. We examine these earthquakes based on regional geomorphological and lithostratigraphical frameworks, field observations of surface ruptures and liquefaction phenomena, and focal mechanisms of historical earthquakes. The Ransiki earthquakes are a set of 29 earthquakes from the Global Centroid Moment Tensor catalogue in the period 1977–2019 (magnitudes of Mw4.9 to Mw7.5). In the east, focal mechanisms show sinistral movement along the east-west trending Yapen Fault including the Mw6.7 earthquake on 21 April 2012. The largest earthquake was on 10 October 2002 (Mw7.5) and along with other earthquakes mainly in the southwest were associated with dextral movement indicated by focal mechanism solutions on the northwest trending Ransiki Fault south of its intersection with the Yapen Fault. The southern part of the Ransiki Fault therefore indicates local north-northeast compression that is also evident in the newly recognised Wainoei Fault south of Yapen Island. The two largest earthquakes (10 October 2002, 21 April 2012) show ground effects associated with liquefaction, indicated by surface offsets, open fissures, and sand blows, that all occurred in saturated sediments of the Ransiki delta. Earthquakes in the Ransiki region show that west-southwest oblique plate convergence between the Australian and Pacific-Caroline plates is partitioned into east-west sinistral strike-slip motion along the Yapen Fault and north-northeast compression associated with the Ransiki Fault.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 101999"},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50191630","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}
引用次数: 0
Editorial – Geological and tectonic evolution of the Arctic 社论-北极的地质和构造演化
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-12-01 Epub Date: 2023-09-26 DOI: 10.1016/j.jog.2023.102001
Morten Smelror, Oleg V. Petrov
{"title":"Editorial – Geological and tectonic evolution of the Arctic","authors":"Morten Smelror,&nbsp;Oleg V. Petrov","doi":"10.1016/j.jog.2023.102001","DOIUrl":"https://doi.org/10.1016/j.jog.2023.102001","url":null,"abstract":"","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 102001"},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50168895","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}
引用次数: 0
Late Paleozoic-Jurassic tectonic evolution of the eastern Deseado Massif in central-southern Patagonia 巴塔哥尼亚中南部东Deseado地块晚古生代侏罗系构造演化
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-12-01 Epub Date: 2023-09-20 DOI: 10.1016/j.jog.2023.101997
C. Navarrete , J. Bastías-Silva , G. Gianni , G. Jalfin , G. Guerra , M. Hurley , D. Chew , J.M. Turra , M. Ocampo , M.B. Lastra , N. Herbst , M. Iglesias , M. Perez Frasette , F. Drakou
{"title":"Late Paleozoic-Jurassic tectonic evolution of the eastern Deseado Massif in central-southern Patagonia","authors":"C. Navarrete ,&nbsp;J. Bastías-Silva ,&nbsp;G. Gianni ,&nbsp;G. Jalfin ,&nbsp;G. Guerra ,&nbsp;M. Hurley ,&nbsp;D. Chew ,&nbsp;J.M. Turra ,&nbsp;M. Ocampo ,&nbsp;M.B. Lastra ,&nbsp;N. Herbst ,&nbsp;M. Iglesias ,&nbsp;M. Perez Frasette ,&nbsp;F. Drakou","doi":"10.1016/j.jog.2023.101997","DOIUrl":"https://doi.org/10.1016/j.jog.2023.101997","url":null,"abstract":"<div><p>Previous tectonic studies have indicated that the peri-cratonic lithosphere, located away from continental margins, is sensitive to far-field stresses propagating from active plate margins, which induce variable deformation. In order to gain a better understanding of potential intraplate tectonic events associated with the geodynamic evolution of the active margin of southwestern Gondwana, we conducted a tectono-sedimentary study of the Permian-Jurassic volcano-sedimentary record in the Deseado Massif, located in southern Patagonia. Our multidisciplinary analysis includes detailed geological mapping of an area of approximately 150 km<sup>2</sup>, structural analysis, geoelectric tomography, 2D seismic data, new geochronological dating, petrographic studies, and stratigraphic loggings of the volcano-sedimentary basin record. This comprehensive data set has allowed us to establish the tectonic, sedimentary, and magmatic evolution of the eastern Deseado Massif. Specifically, we have identified major normal faults associated with the syn-extensional deposition of late Permian and Jurassic sedimentary and volcanic rocks, as well as the Late Triassic emplacement of intermediate and felsic intrusive bodies. Additionally, interspersed large-scale shortening events were recognized, which induced positive tectonic inversion events in the region, recording contrasting stress fields during the analyzed lapse. Based on this, six major intraplate tectonomagmatic events were defined: (i) a potential post-Devonian pre-late Permian exhumation of the Neoproterozoic-early Paleozoic igneous-metamorphic basement, which we tentatively link to the Gondwanide orogeny; (ii) intraplate extension in the Late Permian (255 ± 4 Ma) related to the deposition of the Dos Hermanos Member of the La Golondrina Formation; (iii) Late Triassic (231 ± 3 Ma) intrusion of andesitic bodies, tentatively linked to the inland migration of arc magmatism associated with the South Gondwana flat slab; (iv) subsequent Late Triassic positive tectonic inversion of Permian extensional faults caused by a large-scale contractional event linked to the South Gondwana flat slab; (v) the extension-related emplacement and deposition of Early-Middle Jurassic (176 ± 3 Ma; 172 ± 4 Ma) sedimentary (lacustrine and fan deltas-related deposits), pyroclastic rocks (ignimbrites and ash tuffs), and lavas (lava domes and dykes) related to the Chon Aike silicic large igneous province; and (vi) poorly-constrained post-Middle Jurassic positive tectonic inversion of Jurassic faults. Therefore, we suggest that the geological events preserved in the Deseado Massif provide a key deformational record of the distal effects associated with ancient geodynamic processes that occurred along the southwestern active margin of Gondwana.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"158 ","pages":"Article 101997"},"PeriodicalIF":2.3,"publicationDate":"2023-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50191981","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}
引用次数: 0
Geodetic/gravimetric evidence for mass loss in the subsidence area of Bandung, Indonesia 印度尼西亚万隆沉降区质量损失的大地测量/重力证据
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-09-01 Epub Date: 2023-07-10 DOI: 10.1016/j.jog.2023.101987
Brian Bramanto , Kristian Breili , Christian Gerlach , Irwan Gumilar , Vegard Ophaug , Eko Januari Wahyudi
{"title":"Geodetic/gravimetric evidence for mass loss in the subsidence area of Bandung, Indonesia","authors":"Brian Bramanto ,&nbsp;Kristian Breili ,&nbsp;Christian Gerlach ,&nbsp;Irwan Gumilar ,&nbsp;Vegard Ophaug ,&nbsp;Eko Januari Wahyudi","doi":"10.1016/j.jog.2023.101987","DOIUrl":"10.1016/j.jog.2023.101987","url":null,"abstract":"<div><p>Land subsidence monitoring in Bandung, Indonesia, was initiated in the 2000 s. However, the monitoring has been limited to geometric observations only, which may restrict the further physical interpretation of the cause of the subsidence. In this study, we combine geometric and gravity observation methods to monitor surface subsidence in Bandung. 63 Synthetic Aperture Radar (SAR) images from Sentinel-1A covering the period of 2014–2020 were used to estimate the mean surface geometric changes. For the gravity observations, a hybrid gravity configuration that incorporates absolute (2008–2014) and relative (2011–2016) gravity observations were used to estimate the gravity changes. We estimated geometric changes of up to − 160 mm/yr, indicating rapid subsidence in the greater Bandung area. We obtained gravity changes ranging between − 56.7 and 40.1 <em>μ</em>Gal/yr. Upon subtracting the deformation-induced gravity field from the observed field, we produced a residual gravity field that was presumed to be dominated by the groundwater signal, which was then investigated further. We found that the gravity-derived groundwater signal was mainly negative, indicating subsurface mass loss. We further compared the signal with the modeled gravity effect from deep groundwater observations (1996–2008). The median difference between the observed and modeled groundwater gravity signal was estimated to be 2.8 ± 18.0 <em>μ</em>Gal/yr or equivalent to 0.08 ± 0.55 m/yr in terms of water height if we set the integration cap and groundwater depth to 1.4 km and 150 m, respectively. The discrepancy can be attributed to modeling (simple geohydrological assumption) and measurement (different observation periods and noise) factors. Nevertheless, both measurements indicate that the mass is decreasing due to groundwater depletion, demonstrating the potential of geometric-gravimetric observations to infer sub-surface mass loss.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"157 ","pages":"Article 101987"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45801013","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}
引用次数: 0
Lattice-preferred orientation (LPO) of olivine and amphibole in amphibole peridotites and neighboring hornblendites from Gapyeong, South Korea and implications for seismic anisotropy 韩国加平地区角闪岩橄榄岩和角闪岩中橄榄石和角闪岩的格优选取向(LPO)及其地震各向异性意义
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-09-01 Epub Date: 2023-05-26 DOI: 10.1016/j.jog.2023.101977
Jaeseok Lee, Haemyeong Jung
{"title":"Lattice-preferred orientation (LPO) of olivine and amphibole in amphibole peridotites and neighboring hornblendites from Gapyeong, South Korea and implications for seismic anisotropy","authors":"Jaeseok Lee,&nbsp;Haemyeong Jung","doi":"10.1016/j.jog.2023.101977","DOIUrl":"10.1016/j.jog.2023.101977","url":null,"abstract":"<div><p>Amphibole peridotites and neighboring hornblendites are often found in subduction zones. To understand the effect of amphibole-rich rocks on seismic anisotropy in subduction zones, we studied the lattice-preferred orientation (LPO) of olivine and amphibole in amphibole peridotites and neighboring hornblendites in Gapyeong, South Korea. The major minerals of amphibole peridotites were olivine (31–51% in volume), amphibole (28–47%), and orthopyroxene (7–16%). Amphibole in amphibole peridotites showed relatively high SiO<sub>2</sub> and low TiO<sub>2</sub> and Na<sub>2</sub>O contents (S-type amphibole), indicating that it was formed under supra-subduction conditions. Amphibole in amphibole peridotites showed the type-I, type-II, and type-IV LPO, whereas amphibole in neighboring hornblendites showed the type-III and type-IV LPO. In the case of olivine, most samples showed a mixture of A- and B-type LPO, and one sample showed a mixture of B- and C-type LPO. Many serpentine inclusions were found in olivines. Fourier-transform infrared (FTIR) analysis of the samples showed that the olivines contained a large amount of water (∼29000–45000 ppm H/Si). We also found many dislocations in olivines. These observations indicate that samples showing a mixture of A- and B-type LPO and a mixture of B- and C-type LPO of olivine were deformed under water-rich conditions by dislocation creep. In amphibole peridotites, the P-wave anisotropy of olivine was relatively low (0.9–4.8%), whereas the P-wave anisotropy of amphibole was high (6.5–17.7%). The maximum S-wave anisotropy of olivine was also relatively low (0.87–2.89%), whereas the maximum S-wave anisotropy of amphibole was high (3.81–15.19%). In hornblendites, the P-wave anisotropy and maximum S-wave anisotropy of amphibole were high (6.9–13.6% and 4.27–10.61%, respectively). The P-wave anisotropy and maximum S-wave anisotropy of the amphibole peridotites were in the range of 2.6–8.4% and 1.73–7.30%, respectively. The seismic velocity and anisotropy pattern of amphibole peridotites were more similar to those of amphibole than those of olivine, indicating that the seismic properties of amphibole peridotites were more strongly affected by amphibole than by olivine. Furthermore, the seismic anisotropy of the mixture of amphibole peridotite and hornblendite in subduction zones was also found to be significantly affected by the amphibole LPO in hornblendite.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"157 ","pages":"Article 101977"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48115373","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}
引用次数: 1
Emplacement dynamics of the plumbing system and lava pile of the Paraná Magmatic Province in Morro da Igreja, Santa Catarina, Brazil 巴西圣卡塔琳娜州Morro da Igreja paran<s:1>岩浆省管道系统和熔岩堆的就位动力学
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-09-01 Epub Date: 2023-05-16 DOI: 10.1016/j.jog.2023.101974
Ana Carolina Massulini Acosta , Luana Moreira Florisbal , Jairo Francisco Savian , Breno Leitão Waichel , Mateus Souza da Silva , Ricardo Ivan Ferreira da Trindade
{"title":"Emplacement dynamics of the plumbing system and lava pile of the Paraná Magmatic Province in Morro da Igreja, Santa Catarina, Brazil","authors":"Ana Carolina Massulini Acosta ,&nbsp;Luana Moreira Florisbal ,&nbsp;Jairo Francisco Savian ,&nbsp;Breno Leitão Waichel ,&nbsp;Mateus Souza da Silva ,&nbsp;Ricardo Ivan Ferreira da Trindade","doi":"10.1016/j.jog.2023.101974","DOIUrl":"10.1016/j.jog.2023.101974","url":null,"abstract":"<div><p>The mechanisms of magma ascent, transport and emplacement of the volcanic pile from LIPs are key issues regarding the understanding of the complex construction of volcanic systems and magma transport through the crust. The integrated approach of morphology of the volcanic and subvolcanic bodies, whole rock geochemistry and ASM data provides a robust tool to unravel the flow dynamics of the volcanic bodies and the sequence of the magmatic events. Such approach allows building up a model of construction of the lava pile considering the role played by the plumbing system. This paper investigates the emplacement mechanism of sill and lava flows of the Serra Geral Group (SGG), in the southern part of Mesozoic Paraná-Etendeka Magmatic Province (PEMP) in Brazil. Geologic and geochemical analysis were integrated with anisotropy of magnetic susceptibility (AMS), anisotropy of anhysteretic remanent magnetization (AARM) and rock magnetism experiments on 14 sampling sites in the Morro da Igreja region, top of the lava pile in Santa Catarina. The area is composed of low-Ti basaltic (with predominance of rubbly pahoehoe) and silicic lava flows, both intruded by a tabular sill that reaches a few hundred meters wide. The mafic lava flows are composed of Gramado, Urubici and Esmeralda magma-type basalts and andesite basalts. The silicic lava flows are massive or foliated, classified as Palmas type dacites. The sill has regular columnar joints and is classified as Esmeralda type. Magnetic mineralogy data suggests magnetite or Ti-poor magnetite as the main magnetic mineral for all the igneous rocks, and AARM results show anomalous fabric for the lava flows and normal or intermediate fabric for the sill. Besides the anomalous fabric sites, AMS data provide reliable directional data to infer flow direction for the sill, with initial propagation towards NE, followed by a preferential SE direction of magma flow. For the silicic rocks, the presence of vertical and inclined magnetic foliation suggest a lava dome geometry. The dynamics of the magmatic flow of the sill and lava flows associated with the compositional characteristics of the rocks allows stablishing the stratigraphy of the magmatic events in the area as well as the proposition of an emplacement model for the sequence.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"157 ","pages":"Article 101974"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46254175","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}
引用次数: 0
High-pressure – Low-temperature metamorphic rocks of Iran and their geodynamic significance: A review 伊朗高压-低温变质岩及其地球动力学意义综述
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-09-01 Epub Date: 2023-06-08 DOI: 10.1016/j.jog.2023.101986
Mirmohammad Miri , Ali A. Sepahi
{"title":"High-pressure – Low-temperature metamorphic rocks of Iran and their geodynamic significance: A review","authors":"Mirmohammad Miri ,&nbsp;Ali A. Sepahi","doi":"10.1016/j.jog.2023.101986","DOIUrl":"10.1016/j.jog.2023.101986","url":null,"abstract":"<div><p>High-pressure-low-temperature (HP-LT) rocks such as eclogites and blueschists preserve valuable information about the history and geodynamics of subduction zones. HP-LT rocks exposed in Iran formed during subduction of Paleo-Tethys and Neo-Tethys oceanic lithosphere beneath the Iran microplate and were subsequently exhumed from the Permian to the Early Eocene. The Shanderman and Anarak complexes are associated with Paleo-Tethys, and the Shahrekord, Hajiabad-Esfandaghe, Sistan, Makran, and Sabzevar complexes are related to Neo-Tethys. The assemblage garnet + omphacite + amphibole (Na-, Na-Ca) + white mica + albite ± zoisite formed at the peak metamorphism stage of the eclogites, and amphibole (Na-, Na-Ca) + albite ± white mica ± zoisite ± epidote ± lawsonite formed in blueschists. Retrograde metamorphism replaced peak assemblages with epidote-amphibolite and greenschist facies mineral assemblage (Ca-amphibole + Na-Ca plagioclase + epidote + chlorite). For the various complexes, geothermobarometry calculations and phase diagram modeling show peak P-T conditions of 23 kbar - 600 °C (Shanderman), 14 kbar - 560 °C (Anarak), 25 kbar - 670 °C (Shahrekord), 17 kbar - 530 °C (Hajiabad-Esfandaghe), 24 kbar - 650 °C (Sistan), 15 kbar - 560 °C (Makran), and 17 kbar - 570 °C (Sabzevar). Their retrograde P-T conditions are ∼6 kbar - 470 °C, 7 kbar - 500 °C, 6 kbar - 530 °C, 10 kbar - 450 °C, 8 kbar - 500 °C, 7 kbar − 500 °C and 6 kbar - 490 °C, respectively. The obtained P-T conditions represent a geothermal gradient of 12–16 °C/km for the Paleo-Tethys HP-LT complexes and 7–11 °C/km for the Neo-Tethys. Field and petrographic studies reveal that subduction metamorphism occurred mostly along clockwise P-T paths, except for the Hajiabad-Esfandaghe, Makarn and a subunit of the Anarak complexes that endured counter-clockwise paths. The differences may show a greater subduction angle of Neo-Tethys oceanic lithosphere than Paleo-Tethys, resulting in a cold geothermal gradient and development of continental back-arc basins during the Mesozoic.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"157 ","pages":"Article 101986"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41973191","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}
引用次数: 0
Slab tear and rotation imaged with core-refracted shear wave anisotropy 用核折射横波各向异性成像板撕裂和旋转
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-09-01 Epub Date: 2023-06-17 DOI: 10.1016/j.jog.2023.101985
Laura Petrescu , Andrei Mihai , Felix Borleanu
{"title":"Slab tear and rotation imaged with core-refracted shear wave anisotropy","authors":"Laura Petrescu ,&nbsp;Andrei Mihai ,&nbsp;Felix Borleanu","doi":"10.1016/j.jog.2023.101985","DOIUrl":"10.1016/j.jog.2023.101985","url":null,"abstract":"<div><p>We investigate the complex flow field around the Vrancea slab in Romania, a steeply sinking seismogenic lithospheric block that experienced lateral tear-off and possible rotation. The Vrancea slab is located beneath the South-East Carpathians and generates frequent seismicity despite its remote location from active collisional boundaries. We analyse core-refracted shear wave (SKS) splitting recorded by permanent broadband seismic stations from the Romanian Seismic Network for periods up to 10 years, and compare our results with seismic tomography of the upper mantle. We identify several stations with large backazimuthal variations of SKS fast axis polarization and delay times both in the slab hinge zone, the back-arc and the circum-slab region, indicating complex mantle deformation patterns. To investigate the effect of a two-level rotated slab we invert SKS waveforms using cross-convolutional misfit combined with a neighbourhood search algorithm to model two layers of anisotropy. In the shallow mantle, anisotropy aligns with the upper slab strike and reorients along the strike of the lower slab at depths below the hinge zone. In the back-arc trench-perpendicular anisotropy switches to trench-parallel, due to the recent retreat and roll-back of the slab. Our results have important implications for understanding SKS interference from subducted slab fragments and provide evidence of the recent retreat, break-off and rotation of two Vrancea slab levels sinking into the upper mantle.</p></div>","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"157 ","pages":"Article 101985"},"PeriodicalIF":2.3,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43395835","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}
引用次数: 2
Anisotropic gradients in Iran: Quasi-Love waves illuminate the deep structure and deformation style of the Zagros, Alborz, and Kopet Dagh 伊朗各向异性梯度:准爱波照亮Zagros, Alborz和Kopet Dagh的深部结构和变形风格
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-09-01 Epub Date: 2023-08-17 DOI: 10.1016/j.jog.2023.101989
Amir Sadeghi-Bagherabadi , Lucia Margheriti , Abdelkrim Aoudia , Paola Baccheschi , Francesco Pio Lucente , Farhad Sobouti
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引用次数: 0
Gravimetric inversion and three-dimensional geological modelling of the Piquiri Syenite Massif, southern Brazil 巴西南部皮奎里正长岩体重力反演及三维地质建模
IF 2.3 3区 地球科学
Journal of Geodynamics Pub Date : 2023-08-01 DOI: 10.1016/j.jog.2023.101988
Victor Soares Cardoso, Maria de Fátima Bitencourt, J. Savian, Robson dos Santos Aquino, Cristiane Butori Rivera
{"title":"Gravimetric inversion and three-dimensional geological modelling of the Piquiri Syenite Massif, southern Brazil","authors":"Victor Soares Cardoso, Maria de Fátima Bitencourt, J. Savian, Robson dos Santos Aquino, Cristiane Butori Rivera","doi":"10.1016/j.jog.2023.101988","DOIUrl":"https://doi.org/10.1016/j.jog.2023.101988","url":null,"abstract":"","PeriodicalId":54823,"journal":{"name":"Journal of Geodynamics","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"54756842","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}
引用次数: 0
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