Detailed Structural Mapping Research Articles

The pulse of buying: mapping the conceptual structure and decoding impulse purchase patterns

Purpose This study aims to conduct a rigorous bibliometric analysis of impulse buying research trends and patterns, map the conceptual landscape of the field, identify significant themes and propose a roadmap for future studies in this domain. Design/methodology/approach This study used Snyder’s (2019) four-step systematic review approach. By using a specific search string, articles from the past 21 years (2003–2023) were retrieved from the Scopus and Web of Science databases. Performance analysis and science mapping were conducted using Biblioshiny to analyze the field’s knowledge base. Findings The volume and influence of impulse buying research have surged over the past two decades. The factorial analysis identified three main sub-themes within the impulse buying literature. In addition, Bradford’s law confirmed that the top five journals account for a significant portion of the relevant research. Despite the increased publications, author productivity diverges from Lotka’s law, indicating a few influential authors. This study provides a detailed conceptual map of the research landscape and proposes targeted future research questions by highlighting untapped opportunities. Research limitations/implications This study offers insights for refining marketing strategies and highlights the importance of ethical considerations in marketing, especially during crises. It also strengthens the theoretical foundation of impulse buying by mapping core themes and identifying unexplored areas. Originality/value This study introduces an innovative approach by using factorial analysis with the multiple correspondence analysis technique to develop a detailed conceptual structure map of impulse buying research. It applies bibliometric laws such as Bradford’s law and Lotka’s law to explain the dispersion of research articles. By identifying core themes, this study charts a roadmap for future inquiry, addressing significant gaps and uncovering new research directions.

The Tectonic Framework of Parecis Basin: Insights from a Multiphysics Interpretation Workflow

The Parecis Basin, one of Brazil’s most extensive intracratonic basins, holds significant potential for hydrocarbon exploration. Despite its vast size, Parecis has yet to be extensively explored, with only five wildcat wells drilled. So far, no commercial discoveries have been announced. Regional studies have suggested Paleozoic sedimentation, while recent analyses have revealed a Neoproterozoic infill. Its tectonic model is still a matter of debate, and to date, no detailed structural map for the whole basin has been published. The present work proposes a new detailed structural map of the Parecis Basin based on a four-step interpretation workflow integrating seismic and gravimetric data. The first step includes converting the public 2D seismic lines to the depth domain. The second step is estimating the residual Bouguer anomaly, where the computed residual anomalies should relate to the basin’s tectonic features. The third step comprises the 2D forward modeling of the gravimetric anomalies using the 2D seismic interpretation as a constraint. The final step compiled all the interpreted features into our new structural map. This map reveals the top of the basement, forming a complex framework of horsts and grabens. Normal faults define the main structural style in the basin. Further, we could recognize thick, high-density bodies embedded in the crystalline basement. These bodies consist of Orosian–Calimian (1.8–1.6 Ga) mafic and ultramafic rocks, which may be a potential source for hydrogen exploration in the basin. Subsequent geophysical and geochemical surveys will assess the hydrogen potential in the area.

Tectonic inversion of an intracontinental rift basin: An example from the opening and closure of the Paleo-Tethys Ocean, northern Tibetan Plateau

Abstract Suture zones located across the Tibetan region clearly demarcate the rift-and-drift and continental accretion history of the region. However, the intraplate responses to these marginal plate-tectonic events are rarely quantified. Our understanding of the Paleo-Tethyan orogenic system, which involved ocean opening and closing events to grow the central Asian continent, depends on the tectonic architecture and histories of major late Paleozoic–early Mesozoic orogenic belts. These opening and collision events were associated with coupled intracontinental deformation, which has been difficult to resolve due to subsequent overprinting deformation. The late Paleozoic–early Mesozoic Zongwulong Shan–Qinghai Nanshan belt in northern Tibet separates the Qilian and North Qaidam regions and is composed of Carboniferous–Triassic sedimentary materials and mantle-derived magmatic rocks. The tectonic setting and evolutional history of this belt provide important insight into the paleogeographic and tectonic relationships of the Paleo-Tethyan orogenic system located ~200 km to the south. In this study, we integrated new and previous geological observations, detailed structural mapping, and zircon U-Pb geochronology data from the Zongwulong Shan–Qinghai Nanshan to document a complete tectonic inversion cycle from intraplate rifting to intracontinental shortening associated with the opening and closing of the Paleo-Tethyan Ocean. Carboniferous–Permian strata in the Zongwulong Shan were deposited in an intracontinental rift basin and sourced from both the north and the south. At the end of the Early–Middle Triassic, foreland molasse strata were deposited in the southern part of the Zongwulong Shan during tectonic inversion in the western part of the tectonic belt following the onset of regional contraction deformation. The Zongwulong Shan–Qinghai Nanshan system has experienced polyphase deformation since the late Paleozoic, including: (1) early Carboniferous intracontinental extension and (2) Early–Middle Triassic tectonic inversion involving reactivation of older normal faults as thrusts and folding of pre- and synrift strata. We interpret that the Zongwulong Shan–Qinghai Nanshan initiated as a Carboniferous–Early Triassic intracontinental rift basin related to the opening of the Paleo-Tethyan Ocean to the south, and it was then inverted during the Early–Middle Triassic closing of the Paleo-Tethyan Ocean. This work emphasizes that pre-Cenozoic intraplate structures related to the opening and closing of ocean basins in the Tethyan realm may be underappreciated across Tibet.

The relationship between kinematics and fault geometry for surface coseismic ruptures on across-strike faults: New observations of slip vectors and displacements along the Pisia and Skinos faults from the 1981 Eastern Gulf of Corinth, Greece earthquakes

The relationships between kinematics and fault geometry for the coseismic ruptures from the 24th and February 25, 1981 earthquake sequence in the eastern Gulf of Corinth (Ms 6.7 and 6.4) are analysed. The two earthquakes ruptured faults located across strike rather than along strike as typifies other earthquake sequences. In detail, surface ruptures formed on the sub-parallel Pisia and Skinos Faults, with an 8 km along-strike overlap zone, separated across strike by < 2 km. The largest coseismic offsets occurred in the overlap zone. The 41-year-old ruptures are still well preserved as bedrock fault plane lichen-free stripes and colluvial ruptures, allowing detailed structural mapping at 213 rupture localities. A comparison between our measurements and Jackson et al. (1982) showed no overall consistent signal of post-seismic slip as some of our measurements were greater and some smaller than those recorded in 1981. The ruptures produced a single maximum asymmetric profile (Pisia: maximum throw of 223 cm) and a double maxima profile (Skinos: maximum throw of 109 cm and 130 cm). The shapes of the profiles differed in previous earthquakes on these faults, as evidenced by an older lichen-free stripe, implying non-characteristic earthquakes. Summing the two overlapping throw profiles across-strike reveals a single maximum symmetric bell-like profile. Using the above observations on coseismic offsets, kinematic information, and the geometry of faults, a rupture scenario has been proposed in terms of fault bends and corrugation orientations which suggests that parts of each fault may have ruptured in each earthquake.

LITHO-STRUCTURAL MAPPING USING REMOTE SENSING AND FIELD WORK TECHNIQUES: A CASE STUDY FROM CENTRAL SALT RANGE ARA, RAWAL AND SIDHANDI VILLAGE, PUNJAB PAKISTAN

In the Central Salt Range lithological structural mapping has been a great challenge and of great interest to geologists as it is in rugged and inaccessible mountain terrain. In this paper a comprehensive lithological mapping conducted in the villages of Ara, Rawal and Sidhandi which are located in Central Salt Range region of Punjab, Pakistan. This study uses a combination of remote sensing techniques and field work to elucidate the geological and structural characteristics of the study area. Due to complex tectonic history and mineral resources Central Salt Range is of great geological interest. In this research we combined data from geological field observations and satellite images to produce detailed lithological and structural maps. Remote sensing data help to identify surface features and geological structures. These ground truth observations are complemented by extensive field work including geological mapping and structural analysis. Our work represent a diverse rock composition in the study area, including sedimentary rocks and various fault systems. We classify fault zones on basis of their characteristics, and our structural analysis provides insight into the fault history of the region. Moreover, the study discusses the implications of these geological features for understanding regional tectonics, potential mineral deposits, and land resources in the area. This work demonstrates the synergy between remote sensing techniques and fieldwork in understanding the geological complexities of the Central Salt Range. This work provides valuable information for geological mapping and risk assessment in the area. Additionally, this research demonstrates the importance of a multidisciplinary approach in geological investigations, emphasizing the importance of integrating remote sensing and field data to enhance our understanding of complex geological environments. Keywords: Litho-structural mapping, Remote sensing, Fieldwork techniques, Central Salt Range, Ara, Rawal, and Sidhandi villages, Punjab, Pakistan, Geological analysis, Satellite imagery, Structural mapping, Fault systems, Geological features, Tectonic history, Mineral resources, Sedimentary rocks, Deformation history

Analysis of Karst Surface Anisotropy Using Directional Semivariograms, Slovenia

AbstractThe paper presents a study of the anisotropic properties of the karst surface through the use of semivariograms. Karst is formed by hydrogeological and tectonic deformations that determine the surface and subsurface characteristics of the area. Among the most prominent surface features are dolines, which generally form in a linear direction. Semivariograms can be used to determine both the preferred direction of anisotropy and the degree of anisotropy. The surface exhibits the greatest elevation variability in the direction of the most diverse terrain, corresponding to dolines. The results, based on the eight karst areas studied, show that it is possible to detect and, more importantly, quantify anisotropy in all karst areas, although in some cases it is impossible or difficult to detect visually. The directions of the semivariograms agree very well with those obtained from the visual inspection of the maps, as well as with the orientations of the main faults. The method is therefore very useful for quantitative determination of anisotropy and its interpretation could be greatly improved by using the detailed structural geological maps of the karst.

New insights from conjugate transfer zones in the southern Cairo-Suez province: Implications for deformation history and mechanism

Detailed structural field mapping with the aid of high resolution satellite images were carried out to identify structural style and geometry of Middle Eocene conjugate divergent transfer zones along the southern part of Cairo-Suez Province, Egypt. Eight conjugate divergent transfer zones are recognized between the tips of oppositely-dipping main boundary faults of the mapped fault blocks. The internal geometry of the conjugate divergent transfer zones is represented by elongated fault belts of left-stepping, en echelon normal faults between the terminations of neutral or overlapped boundary faults. Also, dip polarities of the mapped en echelon faults are found to be related to the stepping of the main boundary faults. Accordingly, three main types of conjugate divergent transfer zones are identified in the present study, which are; right-stepping-, left-stepping- and hybrid-stepping-related conjugate divergent transfer zones. Structural analysis of the mapped transfer zones revealed a geometric relationship between the overstepping (Os) of the boundary faults and the total lengths (Tl) of the extended en echelon faults. In addition, the geometry of en echelon faults formed between conjugate divergent transfer zones is attributed to the reactivation of deep seated faults by dextral transtension during the Late Eocene and Oligocene-Miocene times. The interaction of the associated preexisting deep seated Riedel shears is found to have controls on sedimentation and present day architecture. The results of this work highlight the role of preexisting basement structures and boundary faults controlling the internal geometry of transfer zones. Because of the significance of transfer zones in petroleum exploration, the findings of this research provide new data that can be correlated with similar transfer zones in the subsurface and other outcrops in extensional systems.

Subsurface structure of the Tarfaya-Laayoune-Dakhla basin (West African Craton Margin, Morocco) revealed from the analysis of aeromagnetic data

The Tarfaya-Laayoune-Dakhla basin is the largest coastal basin in the Moroccan Atlantic margin. It is filled by a thick Meso-Cenozoic sedimentary cover that overlies unconformably the NW margin of the West African Craton and its Proterozoic to Paleozoic peripheral orogenic belt. In this study, we aim to decipher the structure of hidden part of these terranes and discuss the tectonic evolution of the basin. To achieve these objectives, aeromagnetic data were processed by the application of edge enhancement and depth estimation operators. The combination of their results with geological information and boreholes data allowed the construction of a detailed structural map of the subsurface of the study area. The resulted map delineates three distinct tectonic domains: the Northeastern Domain, the Western Domain and the Southern Domain. These domains exhibit geological evidences of four major tectonic periods: the Eburnean, Pan-African and Variscan orogenies, and the Triassic rifting. The Eburnean dextral transpression event formed a shear-zone with a large magmatic body in the Western Domain. This domain was not affected by the subsequent Pan-African orogeny and the following Ediacaran intracontinental rifting phase. Meanwhile, this event led to the formation of an N- to NNE-trending large half-graben structure in the Northeastern Domain, and an Ediacaran bimodal magmatic series in the Southern Domain. The Paleozoic Variscan orogeny has reactivated the N- to NNE-trending normal faults, allowing thrusting in these domains. Eventually, the Central Atlantic opening event reworked pre-existing reverse faults resulting increases in depth in the Northeastern and Western Domains, meanwhile, the extension was reduced in the Southern Domain.

Silurian‐Devonian Lithospheric Thinning and Thermally Softening Along the Northern Margin of the Tarim Craton: Geological Mapping, Petro‐Structural Analysis and Geochronological Constraints

AbstractWhile the western part of northern Tarim Craton has long been considered as a Paleozoic passive margin, a pronounced Silurian‐Devonian magmatism developed on eastern part of this margin may indicate different but active margin setting. In this contribution, detailed structural mapping, petro‐structural analysis, and geochronological investigations were conducted in the Korla area, eastern part of northern Tarim Craton. Three main generations of fabrics were recognized. The earliest pervasive fabric is an originally sub‐horizontal metamorphic S1 foliation that is in part associated with migmatization characterized by high temperature/low pressure metamorphic mineral assemblages, interpreted as reflecting crustal extension. S1 foliation was affected by D2 contraction forming regional‐scale F2 upright folds associated with sub‐vertical axial planar foliation S2. D3 is marked by development of NW‐SE oriented dextral fault, asymmetric mega‐folding of S2 and spaced NW‐SE‐striking S3 foliation, likely in response to dextral transpression. Geochronological data indicate that D1 extension occurred from ca. 420 to 410 Ma, D2 contraction started around 410 Ma and lasted till 400 Ma or later, and D3 transpression was ongoing around ∼370 Ma. Integrated with regional data, an updated geodynamic model is proposed by interpreting the Central Tianshan, South Tianshan and NE Tarim Craton as an early Paleozoic supra‐subduction system. We suggest that the Silurian‐Devonian event reflects thermal softening and horizontal stretching of the supra‐subduction crust, resulting in drifting of the Central Tianshan continental arc from the proto Tarim Craton in association with opening of the South Tianshan back‐arc basin in‐between.

Salt Tectonics Versus Shortening: Recognizing Pre‐Orogenic Evaporite Deformation in Salt‐Bearing Fold‐And‐Thrust Belts on the Example of the Silica Nappe (Inner Western Carpathians)

AbstractRecognizing salt‐related structures and differentiating them from tectonic shortening‐related anticlines and synclines can be a very challenging task in salt‐bearing fold‐and‐thrust belts, especially in poor outcrop conditions. In this study, we explain several diagnostic structural and sedimentary features that may be used to distinguish pre‐orogenic halokinetic structures from shortening‐related structures on the example of the Silica Nappe (Inner Western Carpathians, Central Europe). Detailed structural mapping in this area resulted in the recognition of several pre‐orogenic salt‐related structures, including linear salt walls and minibasins. Initial evaporite movement started as early as the late Early Triassic, and widespread diapirism occurred during the Middle to Late Triassic, ultimately leading to facies differentiation, with carbonate platform growth in the subsiding minibasins and reduced basinal deposition on top of the diapirs. Later, the inherited salt structures localized the deformation during the Cretaceous Alpine orogeny, and exerted a strong control on the geometry and kinematics of the subsequent deformations. Our new interpretation explains previously unsolved structural problems in the Silica Nappe, like pre‐orogenic thickness variations during the post‐rift phase, frequent young‐on‐older type thrust contacts and multiple folding directions with variable vergencies. The results point out that the Silica Nappe is a fold‐and‐thrust belt, where pre‐orogenic salt tectonics and its effects on the fold‐and‐thrust belt evolution can be studied in detail.

Evolution of Thrace Macula on Europa: Strike‐Slip Tectonic Control and Identification of the Youngest Terrains

AbstractChaos terrains are geologically young and extensively disrupted surface features of Europa, thought to be an expression of the subsurface ocean interacting with the surface. The most prominent examples of this terrain on Europa are Conamara Chaos, and Thera and Thrace Maculae, all prime targets for the upcoming JUICE and Europa Clipper missions to assess the astrobiological potential of Europa. Of the three features, Thrace Macula is currently the least studied and understood. It intersects both Agenor Linea to the north and Libya Linea to the south, two important regional‐scale bands whose interaction with Thrace is yet to be fully unraveled, especially in terms of their relative ages of emplacement and activity. Using Galileo Solid State Imager data and Digital Terrain Models, we conducted detailed structural mapping and terrain analysis to develop a novel hypothesis on the mechanisms involved in the study area. We find that Thrace Macula is bordered along most sides by preexisting strike‐slip faults that have constrained its emplacement and areal distribution. We determine a sequence of events in the area involving the formation of Agenor Linea, followed by that of Libya Linea first and Thrace Macula later, and ultimately by strike‐slip tectonic activity likely driven by Libya Linea, that displaced a portion of Thrace Macula. Therefore, Thrace's subsurface material, uprising along faults postdating its formation, represents the freshest possible that could be sampled by future spacecraft in this region, a major consideration for the upcoming Europa Clipper mission.

Reconciling onshore and offshore geological mapping: lessons from north Cornwall, SW England

Abstract We present the first detailed stratigraphic and structural geological map of offshore north Cornwall and Devon, SW England, based on freely available bathymetric data. Although the bathymetry is often spectacular, revealing fold and fault structures exposed on the seabed at a range of scales and with high resolution, interpretation is not as straightforward as it might appear and depends critically upon both accuracy and knowledge of the onshore geology. Unfortunately, onshore stratigraphic controls are limited and restricted to several thin ‘named shales’ whose coastal outcrops are not always well constrained. In addition, the structure is markedly non-cylindrical on local to regional scales, making seaward projection problematic, while the impact of early thrusting on the stratigraphy has often been previously neglected. We therefore developed a workflow to handle the problems we encountered, including: recognition of vertical to horizontal and 3D to 2D projections; variations in bathymetric data characteristics; prediction of expected seabed outcrop geometries based on coastal structures; incorporation of non-cylindrical effects; and problems with quantitative GIS terrain profiles and structural measurements that result in an absence of such measurements. The geological map produced should therefore be viewed as a step forward, but as forming a base for further detailed bathymetric mapping.

Towards a detailed urban structural mapping using outcrop, geophysical and borehole data integration: Implications for sustainable development

Nowadays, geological conditions and geohazards assessment are essential requirements for sustainable urban planning and development. Hence, with lack of outcrop and near-surface geology, additional geohazards can be imposed. The present study is the first such challenge in one of highly deformed areas in Egypt and, accordingly, an integrated approach for detailed urban geological and structural mapping is given. Therefore, the surface and subsurface field measurements converge on the detailed geological conditions characterization including structural settings in a new urban city, as a case study. In this regard, the measured surface structural data are presented on a detailed geological map considering the surface rock units geometry and distributions. In order to unravel the near-surface geology, geophysical direct current resistivity (DCR) sounding survey is performed to represent subsurface layers distribution considering the surface geological mapping. To reduce the limitations of DCR sounding interpretation, conventional and non-conventional inversion schemes are applied with reference to available borehole data. Evidently, the sum of surface and near-surface mapped fault segments are plotted and analyzed to provide a detailed geometrical structural model. Because the fault rupture hazards and shale layer expansion issues are closely related to the urban sustainable development, a preliminary geohazards assessment is illustrated in the form of fault setbacks calculation and the shale free swelling evaluation. The present approach provides a holistic view of the urban geological mapping and introduces a means of recognizing preliminary potential geohazards problems and/or opportunities at an early stage in any proposed sustainable development, which can support site investigation designing strategies.

Geological structure of karst stratigraphical windows at Škocjan Caves, Slovenia

Within the UNESCO Škocjan Caves, detailed geological structural mapping of the cave passages and of the surface above the cave revealed interesting structural-lithological characteristics of two major collapse dolines, Velika Dolina and Mala Dolina. As a result of the karst processes effects and the formation of collapse dolines, older—stratigraphically lower—carbonates of the Sežana Formation (K22−4) crop out at the surface, underlying rocks of the younger Lipica Formation (K24−5). Here we do not recognize karst windows only in a geomorphological sense but, acknowledging the characteristic lithostratigraphical relationships involved, we suggest use of the new expression “karst stratigraphical window”. Recognizing that karstic areas contain numerous collapse dolines and other doline types, we presume that many more examples of karst stratigraphical windows exist, and that these are distinct from tectonic windows. Our study showed the importance that during the making of detailed geological surface maps of karst areas, it is essential to examine features such as collapse dolines, which may be identified as karst stratigraphical windows. Therefore, providing additional geological data, information about the stratigraphic boundaries and geological structure, in areas without abundance of outcropping rocks is resulting in a more inclusive and comprehensive geological maps.

A single multi-scale and multi-sourced semi-automated lineament detection technique for detailed structural mapping with applications to geothermal energy exploration

Semi-automated algorithms incorporating multi-sourced datasets into a single analysis are increasingly common, but until now operate at a fixed pixel resolution resulting in multi-sourced methods being limited by the largest input pixel size. Multi-scale lineament detection circumvents this issue and allows increased levels of detail to be captured. We present a semi-automated method using a bottom-up Object-Based Image Analysis approach to map regional lineaments to a high level of detail. The method is applied to onshore light detection and ranging (LiDAR) data and offshore bathymetry around the Land's End Granite (Cornwall, UK). The method uses three different pixel resolutions to extract detailed lineaments across a 700 km 2 area. The granite displays large-scale NW–SE fault zones that are considered analogous to those being targeted as onshore deep geothermal reservoirs (2–5 km in depth). Investigation of the lineaments derived from this study shows along-strike variations from NW–SE orientations within granite to NNW–SSE within slate and reflects structural inheritance of early Variscan structures within Devonian slates. This is furthered by analysing these major structures for reservoir potential. Lineaments proximal to these broadly NW–SE features indicate that a damage zone c. 100–200 m wide is present. These observations provide a preliminary understanding of reservoir characteristics for fault-hosted geothermal systems. Thematic collection: This article is part of the Remote sensing for site investigations on Earth and other planets collection available at: https://www.lyellcollection.org/topic/collections/remote-sensing-for-site-investigations-on-earth-and-other-planets Supplementary material: A description of the OBAI method and additional figures are available at https://doi.org/10.6084/m9.figshare.c.6309629

Active detachment faulting controls folding and faulting in western Borneo, SE Asia

The origin of active deformation and structural evolution in large areas of Western Borneo has been highly debated, with two contrasting views involving gravitational tectonics and plate tectonics. The scarcity of field data on land has significantly hampered our understanding of the onshore structures and their relationship with those of the offshore regions. The Baram Delta province is one of the best examples in SE Asia, where debates on the origin and evolution of active tectonic versus gravitational tectonic structures are broadly associated with the complexity of faults and folds in Brunei and Sarawak (Malaysia). In this paper, we present the results of the first large-scale satellite-based structural mapping and the detailed outcrop-based structural mapping in Brunei Darussalam. The results of the satellite-based mapping reveal a major ∼NE-SW trending detachment fault in Brunei and adjacent regions, which is termed the Tutoh fault, with numerous associated secondary faults and folds. The fault acts as a detachment structure onto which several NW-SE trending faults ramp and have asymmetrical folds showing an en echelon fold-fault system. The topographic expression and the recent strike-slip faulting event on the Tutoh fault system suggest that the fault remains active, challenging the discourse that gravitational tectonics is the only cause of active deformation in Borneo.

Strain partitioning in the Variscan deformation of the Marão domain (Central Iberian zone; northern Portugal)

The formation of the Ibero-Armorican Arc, a major structure in the SW Variscan orogeny, induced in most of its southern Iberian branch a heterogeneous sinistral transpressive regime. The presence of pre- and syn-orogenic steep planar anisotropies subparallel to the main WNW-ESE structural trend, gave rise to an important strain partitioning of the Variscan deformation. This lead to the lateral juxtaposition of narrow blocks where simple shear dominated transpression predominates, with wider ones where the pure shear to pure shear dominated transpression is pervasive. This partitioning of deformation is observed from the orogenic macroscale to the mesoscopic and even microscopic scales.The detailed structural mapping of the well exposed Lower Ordovician Armorican quartzites in one of the simple shear dominated sectors (the Marão Mountain in Northern Portugal), coupled with microstructural observations of chosen thin sections, emphasize the coeval development of WNW-ESE sinistral shear zones and subparallel folds. The interference between different Variscan structures, with particular geometries and kinematics, help to understand how transpressive regimes related to the major early oblique orogenic collisions could evolve to late intracontinental orthogonal collision.When the Variscan transpressive regime of Marão is interpreted in the context of the Iberian Variscides, it becomes clear that independent sectors of the same fold belt could compensate the orogenic shortening by different amounts of vertical thickening versus horizontal lateral escape. This explains why tectonic domains where the structures are related with a stretching subparallel to the a kinematic axis (X ≡ akin), could exist in the vicinity of domains where the stretching is subparallel to the b kinematic axis (X ≡ bkin).

Tectonic Geomorphology Of The Jhelum Fault Zone And Its Contiguous Regions In Western Himalaya

The western Himalayan syntaxis represents the region where the major Himalayan structures abruptly curve and the cause of the curvature and the tectonic geomorphology of the region has not been fully explored. The lack of detailed structural maps with extensive field-based data are missing, which is mainly because of the political problems related to border sharing between Pakistan, India, and Afghanistan. However, and fortunately, the usage of satellite derived images has overcome such constrains by providing a robust platform to remotely map such regions. Therefore, the present study was aimed to supplement our previous works in the region by exploring the western portions of the Hazara-Kashmir-Syntaxis. We have used Google terrain imagery to map the evidence for active faulting that involves mapping of triangular facets, displaced and/or faulted topographic ridges, river terraces, alluvial fans and so on. The crosscutting relationships are used to date the faulting events where absolute dates are not available. Our results show that active tectonic deformation is not just limited to the previously mapped structures (e.g. the Kalabagh Fault, the Salt Range Thrust, the Mahesian Anticline, and the Jhelum Fault) but occurs on a broader deformation zone that is delimited by the Chaman fault system in the west, and the Jhelum Fault in the east. The deformation zone in 3D resembles a tectonically formed diamond shaped box that has Salt Range Thrust in front and the Main Boundary Fault at the back with sides delimited by the Chaman and the Jhelum fault systems. The earthquake centroid moment tensor data compliments our geomorphological work, and establishes that transpression is a dominant tectonic process that governs the western regions, which is in comparison to the east where transtension is the norm in the interior Himalayan with reverse and thrust faulting dominant in the frontal regions.

UAV-Borne Imagery Can Supplement Airborne Lidar in the Precise Description of Dynamically Changing Shrubland Woody Vegetation

Airborne laser scanning (ALS) is increasingly used for detailed vegetation structure mapping; however, there are many local-scale applications where it is economically ineffective or unfeasible from the temporal perspective. Unmanned aerial vehicles (UAVs) or airborne imagery (AImg) appear to be promising alternatives, but only a few studies have examined this assumption outside economically exploited areas (forests, orchards, etc.). The main aim of this study was to compare the usability of normalized digital surface models (nDSMs) photogrammetrically derived from UAV-borne and airborne imagery to those derived from low- (1–2 pts/m2) and high-density (ca. 20 pts/m2) ALS-scanning for the precise local-scale modelling of woody vegetation structures (the number and height of trees/shrubs) across six dynamically changing shrubland sites. The success of the detection of woody plant tops was initially almost 100% for UAV-based models; however, deeper analysis revealed that this was due to the fact that omission and commission errors were approximately equal and the real accuracy was approx. 70% for UAV-based models compared to 95.8% for the high-density ALS model. The percentage mean absolute errors (%MAE) of shrub/tree heights derived from UAV data ranged between 12.2 and 23.7%, and AImg height accuracy was relatively lower (%MAE: 21.4–47.4). Combining UAV-borne or AImg-based digital surface models (DSM) with ALS-based digital terrain models (DTMs) significantly improved the nDSM height accuracy (%MAE: 9.4–13.5 and 12.2–25.0, respectively) but failed to significantly improve the detection of the number of individual shrubs/trees. The height accuracy and detection success using low- or high-density ALS did not differ. Therefore, we conclude that UAV-borne imagery has the potential to replace custom ALS in specific local-scale applications, especially at dynamically changing sites where repeated ALS is costly, and the combination of such data with (albeit outdated and sparse) ALS-based digital terrain models can further improve the success of the use of such data.

The enigmatic Ayú metamorphic complex of southern Mexico: A late Palaeozoic polyorogenic metasedimentary prism of the Acatlán Complex reworked in the Jurassic

This contribution deals probably with the most enigmatic metamorphic unit (Ayú Complex) closely associated but in controversial contact relationships with the Palaeozoic Acatlán Complex of southern Mexico, and this is because it represents its deepest, and yet youngest roots now exposed as a wide erosional window in the eastern region of the Acatlán Complex close to the tectonic contact with the Grenvillian Oaxacan Complex. Based on detailed structural geologic field mapping and petrographic analyses of the involved lithologies, including two representative samples from which their detrital zircons were separated and dated to reveal their maximum ages of deposition, our main hypothesis that the Ayú Complex sedimentary protolith constitutes a Palaeozoic polyorogenic unit akin to the Acatlán Complex and metamorphosed twice, in the early Permian (285-270 Ma) and in the Middle Jurassic (174-163 Ma), is supported by our new data instead of an original Triassic-Jurassic sedimentary succession metamorphosed only once in the Middle Jurassic. Our new model for the origin and evolution of the Ayú Complex introduces a paleogeographic late Palaeozoc setting that involved the sequential accretion against the Mexican Grenvillian margin of several tectonic blocks constituting the western Acatlán Complex, which is characterized by a protracted Ordovician-Mississippian deep polyorogenic history. The model also attempted to explain the Middle Jurassic origin of the very high temperature and partial melting metamorphic event that migmatized and pervasively reworked the late Palaeozoic Ayú basin protoliths and its underlying probably Precambrian crust, reinforcing the prevailing view of an extensional, magma-assisted tectonic environment directly associated with the Middle Jurassic breakup of Pangea in the southern region of Mexico.