Basin Subsidence Research Articles

Architecture of lacustrine deposits in response to early Carboniferous rifting and Gondwanan glaciation, Nova Scotia, south‐east Canada

AbstractUpper Palaeozoic lacustrine basin deposits not only record local tectonism but are also an archive to evaluate global palaeoclimate changes linked to the Late Palaeozoic Gondwanan ice age. The Tournaisian Horton Group of Nova Scotia, south‐east Canada, accumulated in rift basins following the final accretion of peri‐Gondwanan terranes to the Appalachians. Sedimentology, mineralogy and geochemistry of the well‐exposed sandstones and shales at the classic Blue Beach section (ca 353.5 to 352 Ma) reveal the interplay of local tectonism and global climatic controls on lacustrine sedimentation. The lacustrine depositional environment gradually transitioned from deep water offshore at the base of the section to wave‐dominated and fluvial‐dominated nearshore at the top. Multiple small transgressive–regressive sedimentation cycles have an average 21 ka duration, likely related to Milankovitch cyclicity. Unusually abundant soft‐sediment deformation structures and landslides are the sedimentary responses to frequent earthquakes during the most active phase of rift subsidence. The overall succession shows changes from a shallowing‐up balanced‐filled to an overfilled lacustrine basin. The chemical weathering intensity index and the Th/K ratio show a longer‐term trend from dry and cool conditions low in the section to humid and warm conditions near the top, with rapid change in the transition period. The section records the peak of the global mid‐Tournaisian carbon isotope excursion and the corresponding cooling event (354 Ma to approximately 351 Ma). The sedimentary succession is a response to long‐term and short‐term climatic cycles influencing lake level and sediment supply during the time of maximum rift basin subsidence recorded by the soft‐sediment deformation structures.

Oligocene Orogen‐Parallel Extension in Southern Tibet During Indian Continental Subduction

AbstractThe controversial history of Indian subduction beneath Asia is crucial to understand the Himalayan orogeny and more in general the geodynamic process of continental subduction. New key information is here presented from the Oligocene‐Pliocene Shiquanhe Basin located in the southwestern Tibetan Plateau. The alluvial‐fan, lacustrine, and braided‐river sediments of the Oligocene Rigongla Formation were non‐conformably deposited onto the Upper Cretaceous Gangdese granitoid rocks and fed from erosion of the batholith itself and of associated Paleogene Linzizong volcanic rocks. Stratigraphic evidence testifies to the development of an orogen‐parallel intracontinental rift along the retro‐side of the Gangdese arc in the Oligocene, at the same time as the Kailas basin formed along the pro‐side of the Gangdese arc. The subsidence of these twin basins may have been caused by steepening of the subducting Indian continental slab or by the passage of a wave of dynamic topography during continuing subduction.

A Study on the Movement and Deformation Law of Overlying Strata and the Self-Healing Characteristics of Ground Fissures in Non-Pillar Mining in the Aeolian Sand Area

The mining area in western China is ecologically sensitive. Coal mining can cause the formation of ground fissures, leading to geological disasters and further accelerating the process of land desertification. In this study, the working face of non-coal-pillar mining in the aeolian sand area was considered as the research object. The movement and deformation law of overlying strata were investigated through field measurements, theoretical analysis, and numerical simulation, and the mechanism governing the self-healing characteristics of ground fissures was revealed. The results demonstrated that the surface angular parameters were lower. This implies that the surface movement and the degree of deformation in non-coal-pillar mining in the aeolian sand area are significant, with a large mining influence range and rapid surface subsidence speed. After the mining of the working face, the resulting failure form of the overlying rock was asymmetric. Boundary ground fissures are typically located within the boundary of the working face, and no outward expansion is primarily observed. Dynamic ground fissures have “waviness” morphological characteristics and asymmetric “M” type development characteristics. A location model as well as a development cycle model of dynamic ground fissures were established for the first time, which can be used to predict the location and period of ground fissures. Based on the motion characteristics of hinged rock block structures, the mechanical mechanism of the self-healing phenomenon of dynamic ground fissures was revealed. A partition monitoring mode of working faces without coal pillar mining was proposed for the first time, which can reduce a lot of manpower and material resources. The coal mining subsidence basin is divided into a natural restoration area and an artificial restoration area. The combination of natural restoration and artificial guidance was used to control the ground fissures and reduce the associated costs. The research conclusions can provide a basis for mining damage evaluation and ecological environment protection in the aeolian sand area.

Limited flexural control of fold-thrust belts on the Jurassic Sichuan Basin, South China

The northern part of the Jurassic Sichuan Basin has long been thought of as a foreland basin in relation to the post-collisional compression along the northern margin of the Yangtze block. However, the exact coupling mechanism between mountain building and basin formation remains unclear. Here, we integrate stratigraphic correlation, basin subsidence analysis and flexural simulation to quantitatively assess the extent to which the fold-thrust belts have controlled basin subsidence. Flexural backstripping of the stratigraphic record, spanning from 201 to 149 Ma, along two cross sections that are perpendicular to the Micangshan fold-thrust belt and the Dabashan fold-thrust belt, respectively, reveals a limited flexural control of mountain loading on basin subsidence. Owing to the short-wavelength nature of plate flexure, the basin-adjacent thrust belts exerted dominant control on basin subsidence only along its margin, with the width of the foredeeps not exceeding ca. 120 km, failing to drive subsidence in the forebulge and backbulge regions. Flexural modeling results suggest that crustal thickening was relatively weak during the Early to Middle Jurassic. This was followed by a more rapid and intense phase of crustal growth in the Late Jurassic, possibly extending into the earliest Early Cretaceous. Compared to the Micangshan region, the Dabashan region has experienced more intense compression during the Late Jurassic. Additionally, our results reveal spatial variations in plate rigidity along the northern margin of the Yangtze block, with greater plate stiffness in the Dabashan region. The presence of residual subsidence, an anomalous long-wavelength subsidence component corrected for both basin-adjacent thrust loading and associated sediment loading, highlights the necessity for an additional driving mechanism for basin subsidence. This residual subsidence was likely dynamic subsidence induced by the flat subduction of the Paleo-Pacific plate (the Izanagi plate) beneath East Asia as the flat slab progressively migrated inland.

Prediction Parameters for Mining Subsidence Based on Interferometric Synthetic Aperture Radar and Unmanned Aerial Vehicle Collaborative Monitoring

Coal mining induces surface subsidence, making rapid and precise monitoring of this subsidence a key area of current research. To address the limitations of D-InSAR technology in capturing large-gradient deformations in the central subsidence basin and the challenges facing UAVs in accurately monitoring small deformations at the basin’s edge, we propose a method for inverting the expected parameters of surface subsidence by synergistically integrating InSAR and UAV monitoring. We determined the cumulative subsidence of monitoring points along the dip and strike observation line of the Banji 110,801 working face between 10 April 2021 and 28 June 2022, employing D-InSAR and UAV techniques. By leveraging the complementary strengths of both monitoring techniques, we fused the two types of monitoring data and verified the error of the fusion data to be within 10 cm through leveling data verification. Simulation experiments utilizing the probability integration method and the Broyden–Fletcher–Goldfarb–Shanno (BFGS) optimization algorithm confirmed that the 10 cm data source error remains within the required limits for probability integration parameter inversion. Finally, the BFGS algorithm was employed to invert the parameters of the probability integration method based on the fusion data results. Subsequently, these inversion parameters were used to predict the subsidence at the monitoring point and were compared with the level measured data. The results demonstrate that the use of collaborative InSAR and UAV monitoring technology for inverting the expected parameters of surface subsidence in the mining area yields superior results, aligning with the actual patterns of ground surface movement and deformation. This study addresses the global need for unmanned monitoring of mining-related subsidence. It employs InSAR and UAV technologies in a synergistic approach to monitor surface subsidence in mining regions. This approach harnesses the strengths of multiple data sources and presents a novel concept for the unmanned monitoring of surface subsidence in mining areas, contributing to environmental protection efforts.

Lithospheric Flexure Controls on Geomorphology, Hydrology, and River Chemistry in the Andean Foreland Basin

AbstractTectonics exerts a strong control over the morphology of Earth's surface that is apparent in active mountain belts. In lowland areas, subtle processes like lithospheric flexure and isostatic rebound can impact Earth surface dynamics, hydrologic connectivity, and topography, suggesting that geomorphic and hydrologic analyses can shed light on underlying lithospheric properties. Here we examine the effect of lithospheric flexure on the geomorphology, hydrology, and river water chemistry of the Rio Bermejo fluvial system in the east Andean foreland basin of northern Argentina. Results show that proximal to the mountain front, foredeep basin subsidence causes sedimentation along a braided channel belt that is superelevated relative to the surrounding flood basin. During floods, water flows from the superelevated channel into the groundwater reservoir, causing a net loss of discharge with distance downstream. Further downstream, forebulge uplift forces channel narrowing, high lateral migration rates, and incision up to 13 m into older river deposits. This incision locally allows groundwater flow into the river, causing a ∼20% increase in river solute load. Groundwater emerges from the forebulge into the backbulge, predominantly as spring‐fed channels. Here, channel migration rates decrease, suggesting a switch from net uplift to subsidence that reduces the depth to the groundwater table. This analysis shows that subtle lithospheric flexure can have significant effects on river channel morphology that determine hydrologic flow paths, and ultimately influence geochemical and ecological patterns. We suggest that these effects may elucidate lithospheric properties that are otherwise inferred from bulk geophysical observations.

Multi-criteria analysis of the possibility of retrofitting the system of rainwater drainage from subsidence basins in a liquidated mine

Multi-criteria analysis of the possibility of retrofitting the system of rainwater drainage from subsidence basins in a liquidated mine

An InSAR Deformation Phase Retrieval Method Combined with Reference Phase in Mining Areas

The acquisition of precise deformation data, including the entirety of the subsidence basin resulting from subterranean mining operations, assumes critical significance in the context of surface impairment monitoring during the course of mining activities. In light of the constraints associated with InSAR technology when applied to the surveillance of expansive deformation gradient mining regions, an innovative approach is advanced herein for InSAR deformation phase retrieval. This approach integrates a reference phase, derivable through a variety of means, including pre-existing models or measurements. Initially, the reference deformation phase is subjected to subtraction from the wrapped InSAR deformation phase, culminating in the derivation of the wrapped phase indicative of the residual phase. Notably, it is posited that the fringe density characterizing the wrapped phase of the residual phase is theoretically diminished in comparison to that of the InSAR wrapped phase. This reduction in complexity in phase unwrapping ensues as a direct consequence. Subsequent to this, the phase retrieval process is effectuated through the summation of the reference phase and the unwrapped phase pertaining to the residual phase. The study harnesses Sentinel-1A and ALOS PALSAR-2 data, employing the PIM-predicted outcomes and GNSS-RTK monitoring outcomes as reference phases for the execution of phase retrieval experiments in two designated study areas. The computation of subsidence is subsequently realized through the combination of the displacement vector depression angle model and the retrieved phase, with the accuracy thereof corroborated through the utilization of leveling data. The experimental findings underscore the efficacy of the reference phase retrieval methodology in securing a more precise deformation phase characterization within expansive deformation gradient mining regions, thereby demonstrating the suitability of this methodological approach.

Burial history and hydrocarbon generation model of the Lower–Middle Jurassic sediments in the Tarnovo depression

This study deals with the geodynamic evolution in the Tarnovo depression, contributes to a better understanding of the burial and thermal history, and gives a model of the generation of hydrocarbons from the Lower–Middle Jurassic rocks. The implications of the complex heat flow scenario for the timing of hydrocarbon generation from the Stefanets Member of the Etropole Formation in selected sections were also analyzed. The Tarnovo depression is defined as a small tectonic unit in the central part of the South Moesian Platform margin developed mainly during the Early–Middle Jurassic. Therefore, the sediment subsidence during the Early–Middle Jurassic is largely a consequence of the tectonic processes in an extensional basin with tilted, fault-bounded, and eventually rotated blocks. There is a trend of increasing tectonic and basin subsidence in southern direction, observed in modeled well sections. The Lower–Middle Jurassic rocks enter the “oil window” in the late Barremian, Hauterivian, or even the late Valanginian towards the south, starting active generation in the middle Aptian. The model shows that gas generation is possible only in the southern and marginal zones of the Tarnovo depression. Among the sequence, the Stefanets Member of the Etropole Formation (Aalenian–early Bajocian in age), composed of shales and siltstones, possesses source rock qualities and good hydrocarbon generation potential. The research model argues for peak of the oil generation from the Stefanets Member at the end of the Barremian up to the Albian to the north and gas generation starting in the Barremian and continuing during the Cenozoic only in the southern part.

Displacements of Fushun west opencast coal mine revealed by multi-temporal InSAR technology

ABSTRACT In this paper, the Multi-Temporal Interferometric Synthetic Aperture Radar (MT-InSAR) technology is adopted to monitor the Line of Sight (LOS) displacement of Fushun West Opencast Coal Mine (FWOCM) and its surrounding areas in northeast China using Sentinel-1 Synthetic Aperture Radar (SAR) images acquired from 2018 to 2022. The spatial-temporal evolution of urban subsidence and the south-slope landslide are both analyzed in detail. Comparison with ground measurements and cross-correlation analysis via cross wavelet transform with monthly precipitation data are also conducted, to analyze the influence factors of displacements in FWOCM. The monitoring results show that a subsidence basin appeared in the urban area near the eastern part of the north slope in 2018, with settlement center located at the intersection of E3000 and fault F1. The Qian Tai Shan (QTS) landslide on the south slope, which experienced rapid sliding during 2014 to 2016, presents seasonal deceleration and acceleration with precipitation, with the maximum displacement in vicinity of the Liushan paleochannel. The results of this paper have fully taken in account for the complications of large topographic relief, geological conditions, spatial distribution and temporal evolution characteristics of surface displacements in opencast mining area. The wide range and long time series dynamic monitoring of opencast mine are of great significance to ensure mine safety production and geological disaster prevention in the investigated mining area.

Tectonic, eustatic and climate controls on facies architecture during the transition to the Neoproterozoic icehouse in the Adelaide Superbasin, Australia

The Tonian to Cryogenian (ca. 1000–635 Ma) marks a crucial turning point in Earth’s history, where tectonic reorganisation and fluctuating oceanic and atmospheric geochemistry plunged the globe into icehouse conditions. This was followed by a postglacial warming period that delivered large volumes of nutrients to the oceans and stimulated eukaryotic evolution. The Adelaide Superbasin in South Australia hosts a thick repository of Neoproterozoic and lower Cambrian sedimentary successions that preserve the depositional conditions during this unique time. In this study, detailed sedimentological data was collected from over 8,350 m of measured section at seven locations across the northern Flinders Ranges. Tonian deposits reveal a carbonate platform setting, where deposition was controlled by basin geometry and proximity to uplifted source areas. In the early Cryogenian, sedimentary successions were affected by the Sturtian glaciation, characterised by two glacial advance-retreat phases that coincide with climatically driven regression. The end of the Sturtian glaciation was marked by basin subsidence and widespread transgression into a more distal subaqueous environment. Despite the lithostratigraphic and sequence stratigraphic similarity between Tonian–Cryogenian successions globally, their correlation remains contentious. The influence of local tectonic regimes during the Tonian created a potential oceanic restriction between developing basins, which challenges the chemostratigraphic correlation between these deposits. Further, limited geochronological ages and opposing interpretations of glacial cyclicity puts into question the timing and extent of the Sturtian glaciation. Conversely, the post glacial transgression appears to be the most globally consistent as it results from climatically controlled sea level rise that was driven by melting ice sheets.

Identifying coal mining subsidence impacts by soil moisture based on optical trapezoid model in Google Earth Engine

AbstractMany coal mining areas overlapped with agricultural land in the world. However, surface subsidence and waterlogging brought on by coal mining inexorably harm the agricultural land. Soil moisture can reflect the variation of mining impact significantly according to the geographic features of the high underground water table, which shows significant spatial gradient variation within the subsidence basin. Previous studies have used site survey and unmanned aerial vehicle (UAV), which are not applicable to large‐scale assessments of the ecological impacts and defining the scale of impacts. Here, we used the Google Earth Engine (GEE) platform and an optical trapezoid model (OPTRAM) to estimate the soil moisture distribution around 50 mining subsidence waterbody samples in eastern China. Based on the spatial variation in soil moisture, the impact boundary of coal mining was determined using buffer analysis and trend fitting. The results showed that: (1) The OPTRAM can well reflect the soil moisture distribution which shows a good correlation between estimated and measured values, with R = 0.83 and RMSE = 0.054. (2) The spatial trend fitting of soil moisture is suitable for evaluating mining impact, and the impact distances are in the range of 96–762 m, 80% of which are located at 128–436 m. We also find that 28% of subsidence waterbody buffer basins were heavily influenced by human activities, and the coal mining impact boundaries cannot be effectively identified. The study provides a new idea to quantify the ecological and agricultural impact boundary of coal mining, which could be applied to other similar regions across the globe.

Faulting, basin formation and orogenic arcuation at the Dinaric–Hellenic junction (northern Albania and Kosovo)

The Dinaric–Hellenic mountain belt bends where two fault systems transect the orogen: (1) the dextral Shkoder-Peja Transfer Zone (SPTZ), active sometime between the Late Cretaceous and middle Eocene; (2) the Shkoder-Peja Normal Fault (SPNF), which accommodated NW–SE directed orogen-parallel extension. The SPTZ dextrally offsets the Dinaric–Hellenic nappes by ~ 75 km, a displacement attributed to reactivation of an Early Mesozoic rift transfer zone in the Adriatic margin during Paleogene subduction of the Pindos Ocean. This subduction involved an initial counter-clockwise rotation of the Hellenides with respect to the Dinarides around a pole at the NW end of the Budva–Krasta–Cukali–Pindos Basin. The SPNF overprints the SPTZ and is a composite structure comprising five fault segments: four of them (Cukali–Tropoja, Decani, Rožaje, Istog) were active under ductile-to-brittle conditions. They downthrow the West Vardar Ophiolite in the hanging wall. The Cukali–Tropoja and Decani segments exhume domes with anchizonal-to-greenschist-facies metamorphism in their footwalls. These structures formed during a first-phase of extension and clockwise rotation, whose Paleocene age is constrained by cross-cutting relationships. A second extensional phase was accommodated mainly by the fifth (Dukagjini) segment of the SPNF, a subsurface normal fault bordering syn-rift, mid-late Miocene clastic and lacustrine sediments in the Dukagjini Basin (DB) that are sealed by Plio-Pleistocene strata. This later phase involved subsidence of Neogene basins at the Dinaric–Hellenic junction coupled with accelerated clockwise oroclinal bending. The driving force for clockwise rotation is thought to be bending and rollback of the untorn part of the Adriatic slab beneath the Hellenides.

The sedimentary facies and tectono-stratigraphic successions of the Carboniferous–Lower Permian deposits in western South Qiangtang Block: Implication for a rifting process on the Gondwana margin

The South Qiangtang Block (SQB) was widely acknowledged as a part of the Cimmerian Continent, which rifted away from Gondwanan margin during the Early Permian. However, the sedimentary response to this rifting event has thus far not been unequivocally confirmed, which makes this event ambiguous. In this contribution, three stratigraphic successions are recognised, which are characterised by distinct facies and record different stages in the tectonic evolution of the basin and associated changes in the rates of basin subsidence and sediment accommodation. Succession 1 comprises glacio-marine deposits which are dominated by dark shales and diamictites (Cameng and Zhanjin formations) originated mainly from both gravity flow and downslope resedimentation. Succession 2 is predominated by shallow-water sandstones of delta setting (lower Qudi Formation). Succession 3 is composed of deposits of tidal flat and platform (upper Qudi and Tunlonggongba formations). The sedimentary facies changes fit well with marine rift-basin successions: (1) Succession 1 clearly records ‘sediment underfilled’ stage characterised by rapid tectonic subsidence, low sediment supply, and marks an early to climax stage of syn-rift; (2) deltaic sandstones facies of Succession 2 records ‘sediment filled and overfilled’ when sediment supply consumes up the accommodation, and marks a late stage of syn-rift during the tectonic quiescence period; (3) tidal-rhythmites of Succession 3 is likely a record of short-term autogenic cycles, indicating a possible post-rift stage. Therefore, these successions within the western SQB during the Early Permian was best explained by the tectonic subsidence resulted from the rifting of the SQB from the Gondwanan margin.

Paleobathymetric reconstructions of the SW Barents Seaway and their implications for Atlantic–Arctic ocean circulation

Unravelling past, large-scale ocean circulation patterns is crucial for deciphering the long-term global paleoclimate. Here we apply numerical modelling to reconstruct the detailed paleobathymetry-topography of the southwestern inlet of the Barents Seaway that presently connects the Atlantic and Arctic oceans. Subaerial topography was likely enough to block Atlantic Water from entering the Barents Seaway in the earliest Eocene (c. 55 Ma). The water may have entered in the middle Eocene (c. 47 Ma) as observed from major basin subsidence, but paleotopographic highs to the east may have hindered connections between the two oceans. From the Oligocene (c. 33 Ma) until the onset of the Quaternary (c. 2.7 Ma), basin shallowing and regional shelf uplift blocked Atlantic Water from entering the Barents Seaway. Our results imply that the Fram Strait remained the sole gateway for Atlantic Water into the Arctic Ocean since its opening in the Miocene until the Quaternary.

A new technical pathway for extracting high accuracy surface deformation information in coal mining areas using UAV LiDAR data: An example from the Yushen mining area in western China

Western China is the world’s major coal-producing area, accounting for 1/3 of global coal production. Large-scale underground coal mining has led to serious ground deformation that has unique spatial and temporal characteristics. However, there are obvious engineering limitations to using GNSS, InSAR, and other common measurement techniques for monitoring mining subsidence. In recent years, researchers have attempted to use UAV LiDAR to monitor subsidence in mining areas. Point clouds are obtained through periodic ground scanning. Surface subsidence information is extracted through the filtering, modeling, and superposition processes. Conventional point cloud processing usually produces subsidence models that are too noisy and only provide information on surface subsidence. This means that it is unable to capture the horizontal ground displacement accompanying subsidence in mining areas, which hinders the practical application of this technology. A local flat point extraction (LFPE) algorithm based on geomorphic features is proposed. The algorithm extracts flat surface point clouds from the scan data and calculates the precise subsidence value of the ground by superposition to facilitate deformation monitoring. The obtained subsidence volume is spatially interpolated based on the unique spatial distribution characteristics of the mining subsidence basin to generate the initial surface subsidence model. By denoising this model, we can obtain a fine surface subsidence model that avoids significant noise caused by non-ground point clouds participating in modeling and superposition in common processing methods. On this basis, we successfully extracted the horizontal displacement information accompanying subsidence by employing sub-pixel correlation using the surface feature images before and after subsidence. The proposed technical pathway was validated by applying it to a coal mining subsidence area in the Yushen mining area in western China. Results demonstrate that, compared to conventional treatments, the proposed subsidence modeling method using laser scanning point clouds improves monitoring accuracy by over 50% while also obtaining the necessary horizontal displacement information for engineering requirements. These findings confirm the efficiency and accuracy of the proposed method for acquiring 3D surface deformation in mining areas.

Integrated Spatiotemporal Analysis of Vegetation Condition in a Complex Post-Mining Area: Lignite Mine Case Study

The motivation for this study arises from the need to monitor the condition of a rehabilitated post-mining areas even decades after the end of the recovery phase. This can be facilitated with satellite derived spectral vegetation indices and Geographic Information System (GIS) based spatiotemporal analysis. The study area described in this work is located in Western Poland and has unique characteristics, as it was subjected to the combined underground and open pit mining of lignite deposits that had been shaped by glaciotectonic processes. The mining ended in early 1970’ties and the area was subjected to reclamation procedures that ended in the 1980’ties. We used the Normalized Difference Vegetation Index (NDVI) and the Enhanced Vegetation Index (EVI) spectral indices derived from Sentinel-2 data for the 2015–2022. period. Then, we applied a combination of GIS-based map algebra statistics (local, zonal and combinatorial) and GI* spatial statistics (hot spot and temporal hot spot) for a complex analysis and assessment of the vegetation cover condition in a post-mining area thought to be in the rehabilitated phase. The mean values of NDVI and EVI for the post-mining study area range from 0.48 to 0.64 and 0.24 to 0.31 and are stable in the analyzed 8 year period. This indicates general good condition of the vegetation and post-recovery phase of the area of interest. However, the combination of spatiotemporal analysis allowed us to identify statistically significant clusters of higher and lower values of the vegetation indices and change of vegetation cover classes on 3% of the study area. These clusters signify the occurrence of local processes such as, the encroachment of aquatic vegetation in waterlogged subsidence basins, and growth of low vegetation in old pits filled with waste material, barren earth zones on external waste dumps, as well as present-day forest management activities. We have confirmed that significant vegetation changes related to former mining occur even five decades later. Furthermore, we identified clusters of the highest values that are associated with zones of older, healthy forest and deciduous tree species. The results confirmed applicability of Sentinel-2 derived vegetation indices for studies of post-mining environment and for the detection of local phenomena related to natural landscaping processes still taking place in the study area. The methodology adopted for this study consisting of a combination of GIS-based data mining methods can be used in combination or separately in other areas of interest, as well as aid their sustainable management.

Rotated Transtensional Basins Formed During Back‐Arc Spreading in Japan: Simultaneous Rapid Tectonic Rotation and Basin Subsidence

AbstractPrevious models of strike‐slip basins do not consider the rotation of the basin itself; however, we show that the Tanakura transtensional basin in Japan was rotated and propose that this basin rotation was related to rifting caused by back‐arc spreading. The Tanakura Basin was formed by displacement along the Tanakura Fault Zone, one of the major active transform faults during the opening of the Sea of Japan. We carried out paleomagnetic analyses and U–Pb dating of the Neogene Tanakura Basin fill rocks. We present a revised, high‐precision stratigraphic record for the Neogene Tanakura Basin fill sequence shows that vertical‐axis counter‐clockwise rotation occurred between ∼17.2 and ∼16.6 Ma. Comparison with paleomagnetic data from adjacent areas shows that rotation was restricted to the basin. In addition, the timing of basin rotation corresponds to the rifting phase of the Tanakura Basin, suggesting that rapid basin subsidence owing to rifting and rapid basin rotation owing to strike‐slip faulting occurred simultaneously. The Tanakura Basin has the characteristics of both rift and transtensional basins that have experienced rotation. This study reveals the detailed relationships between the development and rotation of the Tanakura Basin: rifting‐related subsidence accompanied by basin rotation. Rifting owing to back‐arc spreading may have been accompanied by tectonic basin rotation in Northeast Japan, leading to variations in the magnitude and age of rotation, as the rifting occurred at different times in different locations.

Influence of a Rapidly Uplifting Orogen on the Preservation of Climate Oscillations

AbstractClimate oscillations preserved in sedimentary archives tend to decrease in resolution further back in Earth's history. High‐frequency climate cycles (e.g., ∼20‐Kyr precession cycles) are especially prone to poor preservation due to sediment reworking. Recent studies have shown, however, that given sufficient basin accommodation space and sedimentation rate, shallow‐marine paleoclimate archives record precession‐driven hydroclimate change in mid‐low latitude regions. Our study evaluates how the evolution of a rapidly uplifting orogen influences the recording of astronomical climate forcing in shallow‐marine sedimentary strata in the Taiwan Western Foreland Basin (WFB). Time‐series analysis of gamma‐ray records through the late Miocene–Pliocene Kueichulin Formation shows that during early stages of Taiwan orogenesis (before 5.4 Ma), preservation of precession‐driven East Asian Summer Monsoon variability is low despite increasing monsoon intensities between 8 and 3 Ma. The Taiwan Strait had not formed, and the southeast margin of Eurasia was open to the Pacific Ocean. Consequently, depositional environments in the WFB were susceptible to reworking by large waves, resulting in the obscuration of higher‐frequency precession cycles. From 5.4 to 4.92 Ma, during early stages of emergence of Taiwan, basin subsidence increased while sedimentation rates remained low, resulting in poor preservation of orbital oscillations. After 4.92 Ma and up to 3.15 Ma, Taiwan became a major sediment source to the WFB, and sheltered the WFB from erosive waves with the development of Taiwan Strait. The elevated sediment influx, increased basin accommodation as the WFB developed, and formation of a semi‐sheltered strait, resulted in enhanced preservation of precession‐driven East Asian Summer Monsoon variability.

Integration of DInSAR-PS-Stacking and SBAS-PS-InSAR Methods to Monitor Mining-Related Surface Subsidence

Over-exploitation of coal mines leads to surface subsidence, surface cracks, collapses, landslides, and other geological disasters. Taking a mining area in Nalintaohai Town, Ejin Horo Banner, Ordos City, Inner Mongolia Autonomous Region, as an example, Sentinel-1A data from January 2018 to October 2019 were used as the data source in this study. Based on the high interference coherence of the permanent scatterer (PS) over a long period of time, the problem of the manual selection of ground control points (GCPs) affecting the monitoring results during refinement and re-flattening is solved. A DInSAR-PS-Stacking method combining the PS three-threshold method (the coherence coefficient threshold, amplitude dispersion index threshold, and deformation velocity interval) is proposed as a means to select ground control points for refinement and re-flattening, as well as a means to obtain time-series deformation by weighted stacking processing. A SBAS-PS-InSAR method combining the PS three-threshold method to select PS points as GCPs for refinement and re-flattening is also proposed. The surface deformation results monitored by the DInSAR-PS-Stacking and SBAS-PS-InSAR methods are analyzed and verified. The results show that the subsidence location, range, distribution, and space–time subsidence law of surface deformation results obtained by DInSAR-PS-Stacking, SBAS-PS-InSAR, and GPS methods are basically the same. The deformation results obtained by these two InSAR methods have a good correlation with the GPS monitoring results, and the MAE and RMSE are within the acceptable range. The error showed that the edge of the subsidence basin was small and that the center was large. Both methods were found to be able to effectively monitor the coal mine, but there were also shortcomings. DInSAR-PS-Stacking has a strong ability to monitor the settlement center. SBAS-PS-InSAR performed well in monitoring slow and small deformations, but its monitoring of the settlement center was insufficient. Considering the advantages of these two InSAR methods, we proposed fusing the time-series deformation results obtained using these two InSAR methods to allow for more reliable deformation results and to carry out settlement analysis. The results showed that the automatic two-threshold (deformation threshold and average coherence threshold) fusion was effective for monitoring and analysis, and the deformation monitoring results are in good agreement with the actual situation. The deformation information obtained by the comparison, and fusion of multiple methods can allow for better monitoring and analysis of the mining area surface deformation, and can also provide a scientific reference for mining subsidence control and early disaster warning.