Tectonophysics最新文献

{"title":"Revisiting the dip-slip rate of the North Tehran Fault (Northern Iran) through studying the faulted materials and geomorphic markers","authors":"Maryam Heydari ,&nbsp;Mohammad R. Ghassemi","doi":"10.1016/j.tecto.2024.230610","DOIUrl":"10.1016/j.tecto.2024.230610","url":null,"abstract":"<div><div>The North Tehran Fault (NTF), located south of the Central Alborz Mountains, crosses north of the megacity of Tehran. The NTF is the principal active fault in Tehran, playing an essential role in the risk potential for the near ten million inhabitants of the capital city. Despite this risk, our knowledge about its slip rate is limited to two contradictory quantifications for the western segment of the fault. Slip rates remain unquantified towards the north and east, where it forms a transpressional duplex structure with the Mosha Fault. In this study, we combine detailed fieldwork on the previously documented outcrops of the NTF, including faulted colluvial and alluvial units in the west and uplifted remnants of the pediment surface in the east of the fault. We present new luminescence ages to temporally constrain the fault activity in the Middle-Late Pleistocene in selected sites. Our study in the western NTF reports a cumulative dip-slip rate of 0.56 ± 0.04 mm a⁻¹ for the Kan area and a minimum slip rate of 0.28 ± 0.02 mm a⁻¹ for the Hesarak area outcrops. On the hanging wall of the eastern NTF, a dated pediment surface has risen 579 m relative to the present base level of the Kond River in the footwall. Our analyses suggest that 299 m of such differential movement is thrust-related uplift, which indicates an uplift rate of 1.00 ± 0.12 mm a⁻¹. The dip-slip and shortening rates for the NTF at the Latyan Basin amounts to 1.39 ± 0.17 mm a⁻¹ and 0.97 ± 0.12 mm a⁻¹, respectively.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"897 ","pages":"Article 230610"},"PeriodicalIF":2.7,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143142244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The use of anisotropy of magnetic susceptibility and brittle mesostructures analysis to investigate the tectonic evolution of the oriental Atlas. Case study of the southern edge of the Tunisian trough, NW Tunisian Atlas","authors":"Siwar Ben Elhoul ,&nbsp;Philippe Robion ,&nbsp;Chaouki Khalfi PhD ,&nbsp;Haithem Briki ,&nbsp;Riadh Ahmadi","doi":"10.1016/j.tecto.2024.230603","DOIUrl":"10.1016/j.tecto.2024.230603","url":null,"abstract":"<div><div>This study used a combination of the Anisotropy of Magnetic Susceptibility (AMS) and the structural method to assess the tectonic evolution of the northwestern Tunisian Atlas. A total of 370 oriented specimens were sampled at 18 sites from fine grained Cretaceous sediments ranging from Aptian to Campanian. In order to identify the main magnetic carriers of the AMS signal, representative samples were analysed using thermomagnetic techniques. The results revealed that ferromagnetic (<em>s.l</em>) minerals play a trivial role, favouring the conclusion that paramagnetic minerals are the main contributors. The AMS results showed 12 sites exhibiting normal AMS fabrics, typical for weakly deformed sediments, with a well-defined magnetic lineation and a magnetic foliation sub-parallel to the bedding plane. Only two main orientations of the magnetic lineation were defined and were greatly controlled by the tectonic deformation recorded in the area. Both AMS and structural analyses illustrate a transition from a generally N-S extensional direction for the Aptian-Albian formations to a NW-SE shortening direction for Cenomanian- Campanian series. Except for the Albian-Cenomanian Formation, where the AMS results disaccord with the microtectonic analysis, the roughly N-S magnetic lineation was attributed to the lower Cretaceous <em>syn</em>-deposit rifting phase and was not overprinted by the later NW-SE compressive phases. Thus, it can be concluded that the AMS texture was acquired during early stages of the deformation and once lithified, it was hardly altered by subsequent tectonic movements. Besides, the AMS results also revealed two undefined fabrics: one sedimentary and two inverse. The integrated magnetic and mineralogical investigations confirmed the influence of the magnetic mineralogy on the resulting AMS fabric.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"897 ","pages":"Article 230603"},"PeriodicalIF":2.7,"publicationDate":"2024-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143142296","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}

{"title":"Temporal variation in counterclockwise vertical-axis block rotations across a rift overlap zone, southwestern Ethiopia, East Africa","authors":"A. Erbello ,&nbsp;G. Dupont-Nivet ,&nbsp;T. Kidane ,&nbsp;N. Nowaczyk ,&nbsp;M. Sudo ,&nbsp;D. Melnick ,&nbsp;B. Bookhagen ,&nbsp;S. Brune ,&nbsp;G. Corti ,&nbsp;G. Gecho ,&nbsp;M.R. Strecker","doi":"10.1016/j.tecto.2024.230599","DOIUrl":"10.1016/j.tecto.2024.230599","url":null,"abstract":"<div><div>The southward propagation of the southern Main Ethiopian Rift (sMER) and the northward propagation of the Kenya Rift have generated the Broadly Rifted Zone (BRZ), a ∼ 40-km-wide region of extensional overlap between the Chew Bahir Basin-Gofa Province and the sMER. However, the tectonic interaction between these propagating rifts is not well-understood. We present new paleomagnetic and geochronologic data from Eo–Oligocene (45–35 Ma) and Miocene (18–11 Ma) volcanic and sedimentary rocks from the BRZ. Rock magnetic, alternating field and thermal demagnetization experiments indicate simple titanomagnetite mineralogies carrying a characteristic remanent magnetization from which straightforward magnetization directions were obtained. Site-mean paleomagnetic directions obtained from the analyzed samples reflect stable normal and reversed polarity directions. A comparison of the mean directions obtained for the Eo–Oligocene and Miocene rocks relative to the pole for stable South Africa at the corresponding ages reveals a significant counterclockwise (CCW) rotation of ∼11.1° ± 6.4° and insignificant CCW rotation of ∼3.2° ± 11.5°, respectively, reflecting a decrease in the extent of block rotations through time. Our results are consistent with the regional migration patterns of deformation during rifting. In the context of the regional tectonic evolution toward a narrow zone of extension, much of the deformation associated with block rotations probably occurred prior to the final stages of the emplacement of the Miocene volcanic flows. In light of the structural fabrics in the basement rocks exposed in the sMER, the observed CCW block rotations were likely accompanied and aided by the reactivation of NW-SE-striking basement heterogeneities, supporting the notion that inherited crustal-scale structures play a significant role during rifting across the BRZ.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"897 ","pages":"Article 230599"},"PeriodicalIF":2.7,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143141376","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}

{"title":"Transient seismic velocity variation accompanying an ML 4.2 earthquake on SE margin of the Tibetan Plateau and its implication for fault slip processes","authors":"Yuhan Xiong ,&nbsp;Zhikun Liu ,&nbsp;Xiaoxia Liu ,&nbsp;Yi Meng ,&nbsp;Zhi Chen ,&nbsp;Shaopeng Yan ,&nbsp;Chuantao Geng ,&nbsp;Jinli Huang","doi":"10.1016/j.tecto.2024.230578","DOIUrl":"10.1016/j.tecto.2024.230578","url":null,"abstract":"<div><div>On 8 July 2020, an M_L 4.2 earthquake occurred in the Xiaojiang fault zone along the eastern margin of the Tibetan Plateau. Applied ambient noise monitoring technique to the continuous waveforms from a near-fault small-aperture array, we obtain daily high-resolution variations in seismic velocity before and after the earthquake. When compared with environmental observations, we exclude these factors such as groundwater level, precipitation, temperature, and atmospheric pressure that might significantly influence the seismic velocity changes. We propose that the observed ∼10-day transitional phase from relatively high velocity to low velocity following the M_L 4.2 earthquake, signifies a transition within the fault zone from a relatively compressional state to an extensional one. This transition could be an indicator of transient dilatation deformation during the long-term strike-slip process of the Xiaojiang fault, which is not easily detected by space geodetic measurements. When the fault zone is in extensional state, there is stronger strain-velocity sensitivity, which is verified by local long-period tidal strain.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"895 ","pages":"Article 230578"},"PeriodicalIF":2.7,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743596","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}

{"title":"The rheological structure of East Asian continental lithosphere","authors":"Yujun Sun ,&nbsp;Shuwen Dong ,&nbsp;Mian Liu ,&nbsp;Huai Zhang ,&nbsp;Yaolin Shi","doi":"10.1016/j.tecto.2024.230575","DOIUrl":"10.1016/j.tecto.2024.230575","url":null,"abstract":"<div><div>The rheological structure of the East Asia continent is the key to understanding its broad, heterogeneous, and intense Cenozoic deformation. Based on a refined three-dimensional thermal structure of the lithosphere in this region and the latest strain rate data, we derived a model of the rheological structure of the East Asian continental lithosphere. The strength envelopes, defined by the yield strength of frictional, fractural, and plastic creep, are constrained by the lithological stratification based on previous studies and the depth distribution of earthquakes. The results show large vertical and lateral variations of lithospheric strength in the East Asian continent. A weak lower crust with low effective viscosity is ubiquitous. The rheological structure agrees with the jelly sandwich model in cratons, where the mantle lithosphere is relatively strong. The Tibetan Plateau has the weakest lower crust, with its effective viscosity ranging from 10¹⁹ to 10²⁰ Pa∙s. Its mantle lithosphere is weakened by relatively high temperature; hence, its rheological structure can be described by the crème brûlée model. The lithospheric scale faults and suture zones in and around the Tibetan Plateau, with low strength or viscosity, correspond to the banana split model. The strength of the lithosphere in the Tibetan Plateau and other zones of active Cenozoic tectonics mainly derive from the crust, while the strength of the cratonic lithosphere is dominated by that of the mantle lithosphere. The rheological heterogeneity controls the lateral growth of the Tibetan Plateau and the widespread and differential deformation in the East Asian continent.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"895 ","pages":"Article 230575"},"PeriodicalIF":2.7,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743595","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}

{"title":"Tectonic structures of SW margin of Gondwana from gravity and magnetic anomalies of the Río de la Plata area and their correlation with the Beattie magnetic Anomaly in South Africa","authors":"S.E. Vazquez Lucero ,&nbsp;F. Almaraz ,&nbsp;C.B. Prezzi ,&nbsp;M. Ghidella ,&nbsp;H. Vizán","doi":"10.1016/j.tecto.2024.230571","DOIUrl":"10.1016/j.tecto.2024.230571","url":null,"abstract":"<div><div>The Río de la Plata cratonic area and the adjacent continental platform (South America) have been subject of geophysical and tectonic studies for several decades. However, there are still many uncertainties related with its structural configuration and tectonic evolution. To deepen the knowledge of the tectono-structural characteristics of the cratonic and surrounding areas, we carried out an analysis of magnetic and gravity anomalies, which is highly effective in accurately locating the boundaries of crustal/lithospheric domains/terrains and structures. Additionally, this tectonic characterization allows us to correlate South American geophysical features with their counterparts in southern South Africa (i.e., Beattie Magnetic Anomaly).</div><div>In this study, different filters and techniques were employed to analyze magnetic and gravity anomalies. The gravity anomaly was obtained from global models, whereas the magnetic anomaly was compiled from diverse sources (aerial, terrestrial, and marine data). Particularly, the first vertical derivative, total horizontal derivative, analytic signal, tilt angle and upward continuations were calculated, and 3D Euler Deconvolution was applied.</div><div>Our results confirm the existence, and accurately determine the location, of Río Negro and Colorado transfer zones, Sierra de la Ventana Shear Zone, and extensional structures in the Tandilia System area, here defined as Tandil Trough. Moreover, we propose that the Sierra de la Ventana Shear Zone was shifted northwards in the offshore sector of the study area through sinistral displacement along the Punta Mogotes Shear Zone. Considering the similar rheological contrasts exhibited by the South African margin, we suggest an analogous configuration in the case of the Cape Fold Belt. Additionally, based on our interpretations, and considering previous geophysical studies, we support the proposal that the Beattie Magnetic Anomaly in South Africa and the magnetic anomaly detected beneath the Claromecó Basin would be generated by comparable sources (i.e., Sierra de la Ventana Shear Zone).</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"894 ","pages":"Article 230571"},"PeriodicalIF":2.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706754","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}

{"title":"The deep electrical structure characteristics and regional seismicity of the southeastern Jiali Fault Zone","authors":"Jialin Qi ,&nbsp;Hao Dong ,&nbsp;Leizhe Ji ,&nbsp;Wenbo Wei ,&nbsp;Sheng Jin","doi":"10.1016/j.tecto.2024.230559","DOIUrl":"10.1016/j.tecto.2024.230559","url":null,"abstract":"<div><div>Located in the southeastern Tibetan Plateau, the Jiali fault zone (JLF) is an important strike-slip fault system, which delineates the southern boundary of the south-eastward extrusion of the Tibetan Plateau. The JLF features long-recurrent seismicity and plays an important role in balancing the local stress field. However, previous geophysical studies have mostly focused on regional studies in the northwestern segment and the southeastern end of the JLF. Few geophysical studies have been conducted on the JLF segment in the Eastern Himalayan Syntaxis region. To better understand the deep structures of the JLF and to provide geophysical constraints for the regional seismicity, we propose a crustal-scale resistivity model derived from magnetotelluric profile data across the three branches (Xixingla, Puqu, and Parlung faults) of the southeastern segment of JLF. The three-dimensional electrical structure shows that the JLF is generally characterized by a series of northeast dipping features. Unlike Parlung and Puqu branches, which are currently relatively inactive, the Xixingla fault is imaged to dip steeply in the shallow part of the crust and gradually turninto a gentle dip angle in the deeper section, before ultimately converging with a low-resistivity layer in the mid-to-lower crust. As the recent seismicity shows a combination of thrusting and strike-slip mechanisms, the primary strike-slip tectonic background for the regional seismicity may be modified by the northeastward compression from the subducting Indian Plate. Combined with other geological and geophysical evidence, we suggest that the reverse thrust and strike-slip displacement of faults may jointly contribute to the combined dynamic mechanism for seismicity in this area, due to the intrusion of the Namcha Barwa metamorphic complex beneath the Lhasa terrane.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"895 ","pages":"Article 230559"},"PeriodicalIF":2.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759070","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}

{"title":"Exhumation response to oceanic plateau accretion and oroclinal bending: Low-temperature thermochronology study of Wrangellia terrane on southern Vancouver Island, Canada","authors":"Xin Qiao,&nbsp;Ruohong Jiao,&nbsp;Dante Canil","doi":"10.1016/j.tecto.2024.230562","DOIUrl":"10.1016/j.tecto.2024.230562","url":null,"abstract":"<div><div>Approximately 50 Myr ago, the triple junction of the Kula-Farallon-North America plates converged with the continental margin, causing ridge subduction and the formation, accretion and translation of two oceanic plateaus. We investigate the effects of this tectonic configuration on the exhumation of southern Wrangellia terrane on southern Vancouver Island since the Eocene. We report late Cretaceous to late Oligocene (85.4 to 23.3 Ma) apatite fission track ages (AFT) and, for the first time, Oligocene to early Miocene (36.6 to 14.0 Ma) apatite (U<img>Th)/He ages (AHe) for 16 bedrock samples of Wrangellia. The thermal history modelling of these ages for 13 samples reveals variable cooling patterns between regions. Samples close to the major faults of a fold and thrust belt show accelerated cooling (4–5 °C/Myr) during the Eocene. In the central area, the modelled cooling rates have been slow and generally uniform throughout the Cenozoic (0.5–1.5 °C/Myr), whereas samples from the west coast yielded very slow cooling (&lt;0.5 °C/Myr) from 70 to 30 Ma, followed by moderate cooling (1.5–3 °C/Myr) since. Combining ages, fission track length and thermal history models in this and previous studies, we interpret the moderate-accelerated exhumation of the fold and thrust belt in the Eocene to be a response to oroclinal bending following oceanic plateau accretion. The exhumation pattern of the western side of southern Wrangellia is linked to the ongoing Cascadian Subduction zone ca.30 Ma. This exhumation pattern also supports a hypothesis that all crust of southern Wrangellia was all overlain by sedimentary strata in Eocene before ∼50 Ma, and that an accretionary complex of the Pacific Rim terrane was partly the outboard equivalent of these strata. In the southern Wrangellia, no exhumation response to the Miocene oroclinal bending associated with formation of the Olympic mountains is observed.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"895 ","pages":"Article 230562"},"PeriodicalIF":2.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Upper and lower crustal deformation and residual topography in a continental back-arc: Inferences from the Pannonian-Transylvanian Basins","authors":"Dániel Kalmár ,&nbsp;Attila Balázs","doi":"10.1016/j.tecto.2024.230572","DOIUrl":"10.1016/j.tecto.2024.230572","url":null,"abstract":"<div><div>The topography and subsidence history of sedimentary basins are commonly related to crustal and lithospheric thinning linked to isostasy, also influenced by flexure and dynamic topography. The static component of the topography relative to a reference level can be calculated by the assumption that a lithospheric column consisting of crustal layers and a lithospheric mantle lid float within the asthenosphere. Here, we discuss the observed and calculated residual topography of the Pannonian Basin, i.e. the difference between the actual and calculated isostatic topography. The residual topography calculation is based on new geophysical constraints on the sedimentary, upper and lower crustal and lithospheric thicknesses based on reflection seismic and new receiver function analysis. The crustal thickness decreases from 40 to 45 km beneath the Eastern Alps to 22 km in the eastern Great Hungarian Plain that is floored by less than 60 km thick lithosphere affected by Miocene extension. The sedimentary thickness reaches more than 6 km in the deepest depocenters. The crust is much less attenuated in the Transdanubian Range (28 km), Apuseni Mountains or Transylvanian Basin (32.5–35 km). The interpreted lower crustal thickness reaches maximum 15–20 km in the Eastern Alps, 12–15 km in the Apuseni Mountains, 10 km in the Transdanubian Range and thins to 5 km in the Great Hungarian Plain. The new four-layer lithospheric model shows a much lower residual topography value than previously suggested for the Pannonian Basin. Only the Transdanubian Range is affected by maximum 300 m of positive residual topography, whereas the Transylvanian Basin shows 300–400 m of negative residual topographic values. The former is interpreted to be affected by small-scale asthenospheric upwelling effects, likely also contributing to the Miocene-Pliocene volcanic activity of the area. While the currently uplifting Transylvanian Basin undergoes tectonic re-adjustment linked to the gradual Vrancea slab break-off. Our results demonstrate the important effects of the thick sedimentary succession and the different crustal thinning values on the observed and predicted topographic variations in extensional sedimentary basins.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"894 ","pages":"Article 230572"},"PeriodicalIF":2.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleolatitudinal movements of the eastern Sakarya Zone from Jurassic to Eocene","authors":"Sercan Kayın ,&nbsp;Z. Mümtaz Hisarlı ,&nbsp;Turgay İşseven ,&nbsp;Abdurrahman Dokuz ,&nbsp;Bahadırhan Sefa Algur","doi":"10.1016/j.tecto.2024.230570","DOIUrl":"10.1016/j.tecto.2024.230570","url":null,"abstract":"<div><div>The study area covers a region oriented north-south from the Black Sea coastline in the north to the Kelkit Basin in the south within the eastern Sakarya Zone in northern Türkiye. The objective of this study is to investigate the paleolatitudinal movements of the eastern Sakarya Zone during the Jurassic-Eocene time interval through paleomagnetism. Various volcanic and sedimentary units (e.g., the Şenköy, Berdiga, Mescitli, Çatak, Kızılkaya, and Çağlayan Formations) spanning the time interval from the Early Jurassic to Middle Eocene were identified. A total of 98 locations belonging to Early/Middle Jurassic to Eocene volcanic and sedimentary units were selected for paleomagnetic core sample collection. The samples were subjected to demagnetization through thermal and alternating field methods. Characteristic remanent magnetization directions (ChRM) were obtained. Isothermal remanent magnetization (IRM) and high temperature susceptibility (HTS) measurements were made to identify the minerals responsible for magnetization. To ascertain whether magnetization was acquired through rock formation or as a consequence of subsequent tectonic processes, conglomerate and fold tests were performed. The results showed that magnetization was acquired before folding, i.e., the rocks have primary magnetization. Polarity tests were also conducted using coeval normal and reverse polarity sites. The results indicate that the mean magnetization direction for the Early-Middle Jurassic is 18.1°/55.2° (D/I) and 3.3°/51.5° (D/I) for sedimentary and volcanic rocks, respectively, and 348.7°/46.7° (D/I) for Late Jurassic/Early Cretaceous sedimentary rocks. In the Late Cretaceous period, the mean magnetization direction is 8.0°/49.3° (D/I) and 9.1°/47.0° (D/I) for sedimentary and volcanic rocks, respectively. In the case of the Early/Middle Eocene, the mean magnetization direction is 348.6°/52.7° (D/I) and 5.9°/48.8° (D/I) for sedimentary and volcanic rocks, respectively. In this study, the E/I correction was applied to the Late Jurassic/Early Cretaceous sedimentary rocks, and paleolatitude data obtained from sedimentary rocks were also utilized. Our paleomagnetic results indicate that the eastern Sakarya Zone was situated at latitudes spanning from 27.9° to 35.7° during the Early Jurassic - Middle Eocene time interval. In consequence, the eastern Sakarya Zone constituted a portion of the southern margin of the Eurasian continent during the Late Jurassic and Middle Eocene periods.</div></div>","PeriodicalId":22257,"journal":{"name":"Tectonophysics","volume":"894 ","pages":"Article 230570"},"PeriodicalIF":2.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142691107","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}