Journal of Structural Geology最新文献

{"title":"Ground penetrating radar - based investigation of fracture stratigraphy and structural characterization in karstified carbonate rocks, Brazil","authors":"","doi":"10.1016/j.jsg.2024.105263","DOIUrl":"10.1016/j.jsg.2024.105263","url":null,"abstract":"<div><p>Fracture stratigraphy study for a subsurface sedimentary rock sequence can be a challenging and demanding task. Typically, the data obtained from seismic and well-logs are heavily impacted by resolution issues and are difficult to interconnect. In this work, we document and extract fracture properties (orientation, density, intensity, etc.) from a layered carbonate sequence for fracture stratigraphy characterization. High-resolution subsurface Ground Penetrating Radar (GPR) data images, coupled with drone and previously documented well-log profiles, were analyzed to achieve the structural characterization task. The studied outcrop is localized in the Potiguar Basin (Brazil), where the Cretaceous Jandaíra Formation carbonates are exposed for hundreds of meters. The sequence is subdivided into an upper packstone/grainstone portion and a lower wackestone bed package. We documented the higher fracture intensity/density in the lower bed package portion, highlighting that depositional texture and intra-bed stylolites control the higher fracture distribution in the sequence. Finally, a 3D conceptual model describing the overall results is presented. This model summarizes and shows the innovative fracture stratigraphy method based on the GPR data analysis.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142241467","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 effect of pre-existing structures on the Cenozoic rifting processes: Insights from seismic reflection imaging of the northeastern south China sea","authors":"","doi":"10.1016/j.jsg.2024.105257","DOIUrl":"10.1016/j.jsg.2024.105257","url":null,"abstract":"<div><p>The South China Sea (SCS) opened due to the extension of a compressional setting of the paleo-Pacific subduction. The pre-existing structure significantly influences the geometry of rift basins and the kinematic evolution of the rifting. However, structural evidence of the paleo-Pacific subduction in the northeastern SCS remains enigmatic. The deformation front, serving as the structural evidence of paleo-subduction, is associated with accretionary style deformation and would be reactivated during the subsequent extension phase. In this study, we use a multi-channel seismic profile to investigate the pre-existing structure related to the paleo-Pacific subduction in the northeastern SCS, emphasizing the influence of pre-existing structure on the rift evolution. The seismic profile reveals imbricate reflections in the lower crust. These reflections are interpreted as the deformation front of the Paleo-Pacific subduction. Notably, the deformation front is hyperextended in the Chaoshan Depression. The result of the stretching factors indicates that the ductile lower crust experienced preferential thinning during the rifting beneath the Chaoshan Depression. In the northern part of the profile, a transparent reflection zone was identified and interpreted as a magmatic arc related to Mesozoic subduction. One major achievement of our study is these seismic reflections provide the structural evidence for Paleo-Pacific subduction and reveal that the northeastern SCS has experienced crustal shortening and imbrication through a series of dipping thrusts. Subsequently, we discuss the role of pre-existing structures in lower crustal thinning and continental rifting. We propose the deformation front of the Mesozoic subduction, as a pre-existing weakness, facilitated the kinematic evolution of the rifting in the northeastern SCS during the Cenozoic.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240818","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Intraplate active deformation: Lake Salt fault zone and source of the Obruk (Bor-Niğde) earthquakes, Cappadocia-central Anatolia, Türkiye","authors":"","doi":"10.1016/j.jsg.2024.105256","DOIUrl":"10.1016/j.jsg.2024.105256","url":null,"abstract":"<div><p>Intraplate strike slip deformation structures play a crucial role in understanding how the earthquake are triggered, and respond to long-term deformation in plate interiors. One of the examples for intraplate structure is the Lake Salt Fault Zone (LSFZ) in Türkiye, located at the Central Anatolia region which has hosted a few moderate magnitude earthquakes. The LSFZ extends in NW-SE direction along the eastern border of the Lake Salt basin. In the western and central sections, it exhibits a rather linear trace, and it marks the west-northwestern boundary of the Cappadocian plateau. Along its strike, two big cities, namely, Aksaray and Niğde, and some significant eruption centers (the Hasan, Keçibuyduran and Melendiz Mountain stratovolcanoes) are located, and there is a 12 km right lateral offset. LSFZ has four main segments, namely, Karacaören, Keçikalesi, Obruk and Büyükkaraoğlan fault segments, and they have hosted two moderate-sized (Mw = 5.1 to 5.2) earthquakes (on September 20, 2020 and February 25, 2023) at the localities approximately 5 km ENE and SSW of Obruk Town (Niğde). Their focal mechanisms revealed that the LSFZ exhibits dominantly dextral strike-slip faulting with normal component. The vertical and horizontal displacement rates along the LSFZ are 0.14 mm/yr and 4.6 mm/yr, respectively. The recurrence interval of earthquakes of Mw ≥ 6.7 on the LSFZ is more than one thousand years, owing to the low slip rate. We propose that the LSFZ is in a seismic gap having potential to host a large earthquake.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142228935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of recent tectonic movement in northeast Japan by using long-term GNSS and tide gauge measurements","authors":"","doi":"10.1016/j.jsg.2024.105258","DOIUrl":"10.1016/j.jsg.2024.105258","url":null,"abstract":"<div><p>The study investigates tectonic movements in northeast Japan by using long-term (2000–2022) global navigation satellite system (GNSS) and tide gauge measurements. The effect of the 2011 Tohoku-Oki earthquake including the other eight seismic events that occurred within this period is also discussed using GNSS time-series. The result showed the break in GNSS-time series because of occurred earthquakes and pointed out tectonic movements significantly. The GNSS sites located in the central and southern parts of northeast Japan showed that the velocity vectors have strong internal variation and suggest the existence source of alternative deformation because of geological terranes within the region. A least square approach was used, and the trend of sea-level measurements was fitted with the straight line. The obtained results from tide gauge measurements showed a rising trend at almost every site and indicated lithospheric uprising movement because of tectonic activities. This is possible because of the ongoing subduction of the Pacific and Philippine Sea plates beneath the Eurasian and North American plates.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168343","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Activity and motion characteristics on the southern segment of the Red River fault zone, Yunnan province, China","authors":"","doi":"10.1016/j.jsg.2024.105245","DOIUrl":"10.1016/j.jsg.2024.105245","url":null,"abstract":"<div><p>The longer time for recording large earthquakes on a plate boundary fault, the better that understanding of large earthquake rupture behavior and seismic hazard on the fault zone. However, large earthquakes (<em>M</em> ≥ 7) are rarely recorded on the boundary fault with slow slipping rate, such as the Red River fault zone (RRFZ), which is an important plate boundary fault that marks the southwestern boundary of the Yangtze platform or south China block. There have been no large earthquake records on the southern segments (including the segment in Vietnam) of the RRFZ since historical earthquake records began in 886 AD, except the 1652 Midu <em>M</em> 7 earthquake and the 1925 Dali <em>M</em> 7 earthquake on the northern segment. The southern segment of the RRFZ will not have a large earthquake in the future or as a large earthquake seismogenic zone with a long period of recurrence, remains controversial, in part because of the absence of constraints from geological evidence. This controversial seriously restricts the risk assessment of future large earthquakes on the southern segment of the RRFZ. By careful interpretations of high resolution remote sensing images, in combination with a detailed field geological and geomorphic survey, we found a series of fault valleys and bedrock outcrops from Gasha toYaojie and Yuangjiang to Hekou on the southern segment of the RRFZ. Multiple trench excavation and radiocarbon dating sample analyses show that the mid valley trace in the southern segment of the RRFZ is an active fault. Geological and geomorphic evidence from Gasha to Yaojie and Yuanjiang to Hekou indicate that the mid valley trace in the southern segment of the RRFZ exhibits dip slip and dextral strike slip motion characteristics. This result is inconsistent with those of previous studies that the mid valley trace is purely strike slip. Furthermore, trenches opened on the range front trace in the southern segment of the RRFZ in Ejia are found to still be active, differing from previous studies. Thus, the seismic hazard on the southern segment of the RRFZ should be reevaluated.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142232838","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 September 6, 2021 MW 5.4 Tofalaria earthquake at a weakly active segment of the Main Sayan fault (Eastern Siberia)","authors":"","doi":"10.1016/j.jsg.2024.105255","DOIUrl":"10.1016/j.jsg.2024.105255","url":null,"abstract":"<div><p>We study in detail the M_w 5.4 September 6, 2021 Tofalaria earthquake occurred in a mountain area of the Eastern Sayan which is characterized by a low level of seismic activity. An interest in the seismic event is caused, on the one hand, by poor knowledge about stress-strain field of the crust in the considered region, and, on the other hand, by its relation to the NW segment of the ancient Main Sayan fault – a structural boundary between the Sayan-Baikal fold belt and the tectonically stable Siberian platform. Seismic moment tensors and hypocentral depths of the mainshock and its largest aftershock (M_w 4.6) are inverted from intermediate-period surface wave amplitude spectra calculated at the stations located at teleseismic distances. Integral source parameters of the mainshock, characterizing its spatio-temporal development, are also estimated and the fault plane is determined. Epicenters of 31 aftershocks with M ≥ 1.8, occurred up to the end of 2021, are constrained from body waves recorded at regional seismic stations. The obtained results show that the Tofalaria earthquake occurred under the influence of the SW-NE compression, which is observed in Western Mongolia. Focal mechanism of the largest aftershock and the NE elongation of the aftershock epicentral field (22 km) indicate stress redistribution after the mainshock in a local crustal volume, bordered by small-scale faults.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142240817","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Normal fault localization controls during syn- and post-orogenic extension affecting thin-skinned architecture","authors":"","doi":"10.1016/j.jsg.2024.105243","DOIUrl":"10.1016/j.jsg.2024.105243","url":null,"abstract":"<div><p>Balanced cross sections through thrustbelts affected by post-orogenic extension reveal that normal faults are mostly developed in the backlimbs of pre-existing, asymmetric, fault-propagation and detachment folds. Outcrop study, geological cross section balancing, reflection seismic interpretation and numerical modeling in the Eastern Balkans indicate that the nucleation of these normal faults is affected by the occurrence of plastic strain zones in backlimbs, represented by clusters of small-scale dilatant shear fractures. Thrustbelt segments where these zones did not evolve into thrust faults and became passively rotated into steeper geometries are prone to normal fault development during post-orogenic extension. Instead of developing its own precursor fracture clusters, each normal fault of this type nucleates using pre-existing clusters as a shortcut in its development. Rare occurrences of post-orogenic extension-driven faults, which reactivate entire pre-existing thrust fault ramps or develop in fold forelimbs indicate the existence of other parameters that co-control the development of normal faults in this setting. These parameters include thrustbelt topography as well as variations in décollement geometry and frictional properties.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142129460","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"21Ne and 10Be dating of folded fluvial terraces: Constraining active deformation of the Guman fold along the foothill of the western Kunlun mountains (Xinjiang, China)","authors":"","doi":"10.1016/j.jsg.2024.105244","DOIUrl":"10.1016/j.jsg.2024.105244","url":null,"abstract":"<div><p>Characterizing the active deformation of the foreland is particularly valuable for understanding the dynamics of regional structural evolution within active contractional orogens. We focus on the Guman fold, one of the most prominent fold-and-thrust belts along the foothill of the Western Kunlun Mountains (Xinjiang, China). The anticline growing above the blind thrust faults progressively deforms river terraces. However, contemporaneous terrace surfaces are buried under young deposits north of the fold. We propose a novel method that extends terrace surfaces above the forelimb of the fold within the extent of deformation determined on the seismic reflection profile, to estimate the sediment thickness after abandonment of the terraces. Furthermore, cosmogenic nuclide (¹⁰Be and ²¹Ne) depth profile dating was used to determine the exposure ages of the two terrace surfaces: 413–673 kyr for T1b and 3.7–5.2 Myr for T3b. Combining the age and deformation amount, the slip rate on the frontal fault ramp within the fold is estimated to be 0.4^+0.2/_-0.1 mm/yr and 0.17^+0.07/_-0.03 mm/yr since the abandonment of the T1b and the T3b terrace respectively. These rates represent the recent crustal shortening rate across the Guman fold and likely account for most of the total crustal shortening rate across the Western Kunlun Mountains. However, these rates appear to be notably lower by an order of magnitude compared to the long-term (∼23 Ma) average crustal shortening rate (∼1.1–2.6 mm/yr) in this region. This may indicate a rapid slowing down of the deformation at the scale of the whole Western Kunlun Mountains, possibly related to a regional reorganization.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142098201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of morphotectonic indices for assessing active tectonics: A case study of Acheron river basin","authors":"","doi":"10.1016/j.jsg.2024.105240","DOIUrl":"10.1016/j.jsg.2024.105240","url":null,"abstract":"<div><p>Rivers tend to alter the morphology of their bed and valley as a response to changes in their base level. The study of a drainage basin's tectonic activeness is very important. But especially in areas where rates of vertical tectonic movements are scarce, the morphometric analysis can be proved to be a very accurate method for assessing the effects of neotectonic movements on a drainage network. This method is easy to apply, as it does not require a lot of data. This study concerns the drainage basin of Acheron river in Epirus, Greece. In order to assess of river's response to active tectonic movements, a morphometric analysis was conducted, using a digital elevation model (DEM). Seven morphometric parametres and five geomorphic indices were calculated for the entire basin, as well as 9 sub-basins. Subsequently, each sub-basin was categorised into three categories regarding tectonic activeness (high-medium-low) for each index individually. The relative active tectonics index was also calculated, as the average of the aforementioned morphometric parametres and geomorphic indices. Based on that, each sub-basin was categorised into three categories regarding the overall tectonic activeness (low-medium-high). These results were compared with the drainage pattern and field observations, so as to gain insights on the tectonic activeness of the sub-basins and the entire basin of Acheron.</p></div>","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142097751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A journey through ductile to brittle deformation of rocks: How traditional geoscience benefits from innovations – An introduction","authors":"","doi":"10.1016/j.jsg.2024.105242","DOIUrl":"10.1016/j.jsg.2024.105242","url":null,"abstract":"","PeriodicalId":50035,"journal":{"name":"Journal of Structural Geology","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168231","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}