Foreland Basin Research Papers - Academia.edu (original) (raw)

2025, Journal of Structural Geology

The microstructures of the heterogeneously deformed limestones of the Kolhan Group, Singhbhum Craton (SC), eastern India are investigated to study deformation mechanism, grain size and shape preferred orientation (SPO) development. The texture of the deformed rocks is analyzed by Electron Back-Scattered Diffraction (EBSD) in order to determine crystallographic preferred orientation (CPO) development in calcite grains. The c-axis pattern in protomylonite and mylonite define girdle patterns developed perpendicular to local shear planes showing monoclinic symmetry. The latter is interpreted in terms of a top-to-south shear, which is consistent with the observed microstructural and fabric data from the deformed rocks. The Anisotropy of Magnetic Susceptibility (AMS) studies are performed on 22 heterogeneously strained limestone specimens to document strain variation within the Kolhan rocks. The field fabric, SPO data measured from calcite and mica grains (κ cal and κ mi ) and calcite CPO data are compared with observed variation in AMS fabric intensity (P j) across the Kolhan basin. Integration of these data sets help to establish presence of large internal thrust planes within the Kolhan basin, which form a part of the regional foreland vergent thrust system developed along the northern margin of the SC.

2025

After a decade of research the functions of circular enclosures of the middle Neolithic are still debated. In a project funded by the German Research Foundation (DFG) two of these roundels were excavated in order to learn more about their structure, history of construction, their function as well as their spatial characteristics. Based on high-resolution digital elevation models, possible orientations towards topographical and astronomical features are systematically investigated using a GIS-based visibility analysis and a self-developed tool in Wolfram Mathematica. In this article preliminary results of two (partially) excavated roundels in the northern Forelands of the Harz Mountains are presented.

2025, Journal of South American Earth Sciences

We present new U-Pb LA-ICP-MS data from the Central Andean foreland basins combined with new and published stratigraphic information in order to reconstruct the Miocene fragmentation of the Andean foreland between 26 and 28°S. The disruption of this foreland basin and the subsequent development of elevated intermountain basins have been the focus of several studies. However, the absence of temporal constraints in the Miocene to Pliocene sedimentary record of the low elevation Choromoro and Tucuman foreland basins has presented an obstacle for precise paleogeographic reconstructions. We describe 11 discontinuous stratigraphic sections and use the U-Pb LA-ICP-MS method to date 10 pyroclastic-bearing sediments in order to reconstruct the stratigraphic evolution of the Choromoro and Tucuman basins. We combine our results with published stratigraphic and thermochronologic data from adjacent basins to present a refined Miocene paleogeographic model. In a first stage, a continuous Early Miocene foreland lacustrine basin developed, filling up the preexisting Paleogene topography. The second stage is characterized by basin unroofing around ~12 Ma; the easily eroded sedimentary cover was removed, leading to the uplift of the underlying basement rocks and the segmentation of the lacustrine system. In the third stage, relief increase took place after ~6 Ma due to the low erodibility of the basement blocks; as a result, stable fluvial systems developed. Progressive relief development caused pronounced unconformities in the basins and the development of proximal fluvial-gravitational depositional systems after 3 Ma. This model emphasizes on the relations between tectonics, climate, and erodibility, and their control on the evolution of the depositional systems and relief.

2025, Iraqi Journal of Science

The Late Maastrichtian–Danian phosphatic succession prevails as a deposit to the west of Rutbah region, Western Iraq. This is manifested through the lithostratigraphic sections of boreholes (K.H5\6 and K.H 5\8) drilled previously in the area. The succession is mainly composed of phosphate, shale, porcelanite, oyster and foraminiferal carbonate lithofacies belonging to Digma and Akashat formations. Three facies associations are distinguished during the study: the phosclast planktonic (FA1) that dominates the outer ramp, the phosclast foraminiferal (FA2) that dominates the mid ramp, and the quartz dolomitic phosclast (FA3) present in the inner ramp. These facies’ associations are differentiated into seventeen microfacies types. Microfacies analysis and fauna contents have shown gradual facies variation grading from a high energy inner ramp environment in the east to a low energy deep water ramp environment in the west.

2025, Przegląd Geologiczny

2025, Correlation Between Strength and Durability of Sandstones from the Dumri Formation, Tinau Khola Area, West-Central Nepal

Strength and Durability indices are two significant geotechnical criteria that can describe rock fragments' strength and weathering resistance. The Dumri Formation is the youngest and thickest of the Tansen Group, Lesser Himalaya. A thick succession of medium-grained, bluish-grey quartzose sandstone and red-purple shale represents it. To assess the quality of the sandstones, different laboratory tests and analyses were made to characterize the physical and mechanical properties of the sandstones. Physical properties were greatly influenced by composition and texture. The intact rock strength was figured out by the point load strength index (PLSI) and Aggregate impact value (AIV). Rock durability against slaking was determined using the slake durability index (SDI) test. The strength and durability indices were correlated through regression analysis. Sandstones assessed were classified as lithic and feldspathic wacke. Sandstones exhibited high resistance to slaking and are extremely durable (SDI = 99.53-99.86%) under a two-cycle test. Sandstones are strong to very strong (PLSI = 5.28-8.92 MPa) and possess high impact resistance (AIV = 6-9%). The correlation between PLSI and SDI was found to be high (r=0.86). Similarly, a correlation between AIV and SDI was (r=0.98), and between AIV and PLSI was (r=0.86).

2025, Turkish Journal of Earth Sciences

The Karaçayır syenite, intruding the Palaeozoic crustal metamorphics and unconformably overlain by Upper Paleocene to Eocene Tokuş formation in the north of Sivas (east-central Anatolia), has been studied with respect to 207 Pb-206 Pb single zircon evaporation, biotite 40 Ar-39 Ar, and apatite fission-track geothermochronology. 207 Pb-206 Pb single zircon evaporation dating yields an age of 99.0±11.0 Ma (Cenomanian-Turonian) which is considered to be the intrusion age. Biotite 40 Ar-39 Ar age determination gives a cooling age of ca. 65 Ma. Apatite fission-track dating, combined with T-t modeling based on track-length distribution data, determines a fast tectonic exhumation with an uplift rate of > 1 mm/a which occurred 58-61 Ma ago. This Middle Paleocene fast tectonic uplift is considered to have resulted from a compressional regime induced by the collision between the Tauride-Anatolide platform (TAP) and the Eurasian plate (EP) along the İzmir-Ankara-Erzincan (İAE) suture zone following the closure of the northdipping subducted İAE ocean which belongs to northern Neo-Tethyan realm. This compressional regime has also formed the peripheral foreland basins in central Anatolia.

2025, Turkish Journal of Earth Sciences

2025

Predictive exploration methods are possible due to the linear alignment of many oil and gas fields in the Alberta Basin. In the Athabasca Basin, fault networks may be of interest for uranium exploration. Knowledge of basement structure is important in the exploration for diamonds. The large, fault-related Pine Point Mississippi-Valley-type mineral deposit in the Phanerozoic sedimentary cover lies in the Northwest Territories only a short distance north of the Alberta border. Two fundamentally different types of crystalline-basement structures, formed in different tectonic conditions, are recognized in the Alberta Basin: 1) Archean and Early Proterozoic (Hudsonian and older) ductile orogenic structures, and 2) Middle Proterozoic to Recent cratonic ones. The influence of ancient ductile structures on the Alberta Basin is largely confined to the control on Early Paleozoic depositional and drape patterns by the Precambrian erosional basement relief, which is to some extent related to th...

2025, Minerals

Foreland fold and thrust belts always represent a complex diagenetic history of carbonate succession, particularly multiphase dolomitization, due to the multi-sourcing nature of fluids affecting syn-to post-depositional successions. The present work documents a comprehensive study on the diagenetic changes, particularly dolomitization patterns in the Jurassic carbonates (Samana Suk Fm) in the Lesser Himalayan fold and thrust belt, NW Pakistan. To better understand the processes involved, integrated field/petrographic, geochemical, isotopic, and micro-thermometric studies were carried out. Field observations indicate that dolostones appear as light grey to brown stratabound and patchy units within the formation. Petrographic analysis reveals that fabric destructive matrix dolomite (RD-I) and fabric preserving replacive dolomite (RD-II) phases are present as distinct units. In addition, saddle dolomite cement (SD) and fracture-filling calcite (CC) are also observed in association with...

2025, Ingeniería Investigación y Tecnología

The Lower Paleogene Chicontepec Foreland Basin at the southern region of the Tertiary Tampico-Misantla Basin at East-Central Mexico, resulting from the loading pressure of the uplifted and thrust-folded front of the Sierra Madre Oriental, on the passive, unfolded and thermally in subsidence Cretaceous basement, during the northeastward tectonic stresses from the Laramide Orogeny, against the Tuxpan Island eastern. The foreland basin consists stratigraphically of complex low density turbidite systems, being their detached and non-channelized outer-fan lobe facies the most conspicuous, composite by disperse and discontinue sandy lenses with tight and highly cemented calcareous lithofacies, micro-fractured and with micro-vugs by dissolution. The hydrocarbons flowed vertically from the underlay Cretaceous and Upper Jurassic rocks through the NW-SE dextral transpressive strike-slip fault planes and fractures, then spread laterally toward the micro-fractured sandy lenses and within the unconformable erosive surfaces, bounding the depositional systems (systems tracts), at different levels of the Chicontepec stratigraphic column, in a hybrid petroleum system with low permeability unconventional reservoirs.

2025, Geological Quarterly

Auriferous sediments in the East Sudetic Foreland region include up to five gold-bearing horizons associated with preglacial and Quaternary fluvial sediments. The largest placer potential lies in the preglacial (Eopleistocene?) drainage system, primarily in palaeochannels of the Bia³a G³ucho³aska River. The White Gravel series is the richest gold-bearing horizon. It contains between 0.37 g/m 3 Au near the base and <0.10 g/m 3 Au in its upper part. Maximum gold grade occurs in the first 1-2 m above the contact with the bedrock. Gold concentration in this area was controlled by the ability of streams to aggradation and the development of sedimentologic traps, where gold was accumulated during the preglacial valley erosion. Oblique orientation of the palaeo-Bia³a G³ucho³aska valley and its tributaries to the regional ice-flow direction probably prevented the glaciers from eroding deeply into the palaeochannels. From the exploration prospective, study of palaeochannel systems in the vicinity of Otmuchów-Prudnik could identify other buried placer gold occurrences. Gold-bearing sediments, correlated stratigraphically with the Bia³a G³ucho³aska palaeochannel White Gravels occur in several other areas, including the Nysa K³odzka, Kwisa and Kaczawa valleys.

2025, Journal of Asian Earth Sciences

The Siwalik Group which forms the southern zone of the Himalayan orogen, constitutes the deformed part of the Neogene foreland basin situated above the down¯exed Indian lithosphere. It forms the outer part of the thin-skinned thrust belt of the Himalaya, a belt where the faults branch o a major deÂ collement (MD) that is the external part of the basal detachment of Himalayan thrust belt. This deÂ collement is located beneath 13 Ma sediments in far-western Nepal, and beneath 14.6 Ma sediments in mid-western Nepal, i.e., above the base of the Siwalik Group. Unconformities have been observed in the upper Siwalik member of western Nepal both on satellite images and in the ®eld, and suggest that tectonics has aected the frontal part of the outer belt since more than 1.8 Ma. Several north dipping thrusts delineate tectonic boundaries in the Siwalik Group of western Nepal. The Main Dun Thrust (MDT) is formed by a succession of 4 laterally relayed thrusts, and the Main Frontal Thrust (MFT) is formed by three segments that die out laterally in propagating folds or branch and relay faults along lateral transfer zones. One of the major transfer zones is the West Dang Transfer Zone (WDTZ), which has a north-northeast strike and is formed by strike-slip faults, sigmoid folds and sigmoid reverse faults. The width of the outer belt of the Himalaya varies from 25 km west of the WDTZ to 40 km east of the WDTZ. The WDTZ is probably related to an underlying fault that induces: (a) a change of the stratigraphic thickness of the Siwalik members involved in the thin-skinned thrust belt, and particularly of the middle Siwalik member; (b) an increase, from west to east, of the depth of the deÂ collement level; and (c) a lateral ramp that transfers displacement from one thrust to another. Large wedge-top basins (Duns) of western Nepal have developed east of the WDTZ. The superposition of two deÂ collement levels in the lower Siwalik member is clear in a large portion of the Siwalik group of western Nepal where it induces duplexes development. The duplexes are formed either by fartravelled horses that crop out at the hangingwall of the Internal DeÂ collement Thrust (ID) to the south of the Main Boundary Thrust, or by horses that remain hidden below the middle Siwaliks or Lesser Himalayan rocks. Most of the thrusts sheets of the outer belt of western Nepal have moved toward the S±SW and balanced cross-sections show at least 40 km shortening through the outer belt. This value probably under-estimates the shortening because erosion has removed the hangingwall cut-o of the Siwalik series. The mean shortening rate has been 17 mm/yr in the outer belt for the last 2.3 Ma.

2025, Annals of Geophysics

The seismic activity in the Eastern Carpathians area is poorly recorded (a few hundreds of small-to-moderate earthquakes in the Romanian catalogue over the last century).

2025, Natural Hazards and Earth System Sciences Discussions

Seismic-induced ground motion at a site is generally influenced by seismic source, propagation path and local site conditions. Over the last several decades, researchers have consistently asserted that for near site attenuation, the spectral parameter kappa is subject primarily to site conditions. In this research we estimated parameter kappa based on the acceleration amplitude spectrum of shear waves, from the selected recordings of local earthquakes from seismological stations situated in the western part of Croatia from the slope of the high-frequency part. The spatial distribution of individual kappa values is compared with the azimuthal distribution of earthquake epicentres, with 𝑉 𝑠30 values and the published coda-Q values for each station, as well as with isoseismal maps for several stronger events in the investigated area, along with the geological features. The dextral shift of crustal segments and frontal thrust of the External Dinarides along the Kvarner fault zone has probably had an impact on the geometry of the kappa parameter contour lines. These results are important for gaining further insight into the attenuation of near-surface crust layers in the Northwestern External Dinarides and the associated Adriatic foreland, as well as in similar geotectonic settings.

2025, BIO Web of Conferences

Biogenic gas was previously considered as a drilling hazard before it has become captivating with competitive price and due to high demand. This study was done to diagnose rock formations which are prospective match up to revolutionary hydrocarbon system variables and to cast up volume estimation. The North Papua Basin, which classified as a foreland (hybrid) basin, is reckoned to have significant gas potentials from well data compliments Pleistocene Mamberamo sandstone with robust biogenic gas parameters, high methane composition (99-100%) and low CO2, H2S or N2 contents. Rapid sedimentation and low geothermal gradient play great role to establish effective biogenic gas system, followed by young-aged reservoir parameter. Field data comprise of soil gas sample supports geochemical investigation. Petrophysical and seismic interpretation results, as follow, are applied to assist volumetric calculation and uncertainty analysis using Monte Carlo simulation. Source rock evaluation from t...

2025, Frontiers in Earth Science

2D seismic reflection profiles revealed the presence of a triangle zone at the frontal part of the western Kura foreland fold-and-thrust belt of the pro-wedge of the Greater Caucasus. To understand the triangle zone geometry, seismic interpretations should be substantiated by forward kinematic modeling, supported by analog experiments. This study presents a new structural model for the region by integrating field observations, well data, and seismic reflection data. East-West directed along-strike structural variation of the frontal thrust is observed on the interpreted seismic profiles which affected the fold geometry. The Bitsmendi breakthrough fault-propagation fold gradually transits into a wedge structure in the W-E direction and is represented by the triangle zone. The seismic profiles interpretation results completely match with analog models of similar triangle zones. The analysis of the experimental results helps us to further understand the kinematic evolution of natural s...

2025, Geophysical Journal International

We use two gravity profiles that we measured across Central Nepal, in conjunction with existing data, to constrain the mechanical behaviour and the petrological structure of the lithosphere in the Himalayan collision zone. The data show (1) overcompensation of the foreland and undercompensation of the Higher Himalaya, as expected from the flexural support of the range; (2) a steep gravity gradient of the order of 1.3 mgal km x1 beneath the Higher Himalaya, suggesting a locally steeper Moho; and (3) a 10 km wide hinge in southern Tibet. We compare these data with a 2-D mechanical model in which the Indian lithosphere is flexed down by the advancing front of the range and sedimentation in the foreland. The model assumes brittle Coulomb failure and nonlinear ductile flow that depends on local temperature, which is computed from a steadystate thermal model. The computed Moho fits seismological constraints and is consistent with the main trends in the observed Bouguer anomaly. It predicts an equivalent elastic thickness of 40-50 km in the foreland. The flexural rigidity decreases northwards due to thermal and flexural weakening, resulting in a steeper Moho dip beneath the high range. Residuals at short wavelengths (over distances of 20-30 km) are interpreted in terms of (1) sediment compaction in the foreland (Dr=150 kg m x3 between the Lower and Middle Siwaliks); (2) the contact between the Tertiary molasse and the meta-sediments of the Lesser Himalaya at the MBT (Dr=220 kg m x3 ); and (3) the Palung granite intrusion in the Lesser Himalaya (Dr=80 kg m x3 ). Finally, if petrological transformations expected from the local (P, T) are assumed, a gravity signature of the order of 250 mgal is predicted north of the Lesser Himalaya, essentially due to eclogitization of the lower crust, which is inconsistent with the gravity data. We conclude that eclogitization of the Indian crust does not take place as expected from a steady-state local equilibrium assumption. We show, however, that eclogitization might actually occur beneath southern Tibet, where it could explain the hinge observed in the gravity data. We suspect that these eclogites are subducted with the Indian lithosphere.

2025, Earth surface dynamics

The evolution of the drainage system in the Eastern Alps is inherently linked to different tectonic stages of the alpine orogeny. Crustal-scale faults imposed eastward-directed orogen-parallel flow on major rivers, whereas late orogenic surface uplift increased topographic gradients between the foreland and range and hence the vulnerability of such rivers to be captured. This leads to a situation in which major orogen-parallel alpine rivers such as the Salzach River and the Enns River are characterized by elongated east-west-oriented catchments south of the proposed capture points, whereby almost the entire drainage area is located west of the capture point. To determine the current stability of drainage divides and to predict the potential direction of divide migration, we analysed their geometry at catchment, headwater and hillslope scale covering timescales from millions of years to the millennial scale. We employ χ mapping for different base levels, generalized swath profiles across drainage divides and Gilbert metrics -a set of local topographic metrics quantifying the asymmetry of drainage divides at hillslope scale. Our results show that most drainage divides are asymmetric, with steeper channels west and flatter channels east of a common drainage divide. Interpreting these results, we propose that drainage divides migrate from west towards east so that the Inn catchment grows at the expense of the Salzach catchment and the Salzach catchment consumes the westernmost tributaries of the Mur and Enns catchments. Gilbert metrics across the Salzach-Enns and Salzach-Mur divides are consistent with inferred divide mobility. We attribute the absence of divide asymmetry at the Inn-Salzach divide to glacial landforms such as cirques and U-shaped valleys, which suggest that Pleistocene climate modulations are able to locally obscure the large-scale signal of drainage network reorganization. We suggest that the eastward-directed divide migration progressively leads to symmetric catchment geometries, whereby tributaries west and east of the capture point eventually contribute equally to the drainage area. To test this assumption, we have reconstructed the proposed drainage network geometries for different time slices. χ mapping of these reconstructed drainage networks indicates a progressive stability of the network topology in the Eastern Alps towards the present-day situation.

2025, Geological Journal

The tectonic/stratigraphic interpretation of the Cambro-Ordovician rocks exposed in the south-westernmost sectors of the Sardinia island (i.e., belonging to the Bithia Formation or Unit) is still a hot point of discussion. A debated question is also the age of the metavolcanics interbedded in these rocks. In order to provide a clear answer to this problem, in this paper, we provide new U-Pb zircon dating and a petrographic-geochemical comparison of metavolcanics interbedded within the Bithia Formation with similar Sardinian Ordovician calc-alkaline rocks. The Bithia metavolcanics plot in the rhyodacite/rhyolite field. They show negative troughs for Nb and Ta, negative anomalies for Sr, P, and Ti, and positive peaks for Cs, Rb, K, Th, U, and Pb in the multielement diagram normalized to primitive mantle and significant LREE enrichment, marked negative Eu anomaly, and flat HREE patterns in the chondrite-normalized REE diagram. Owing to these geochemical features, the Bithia metavolcanics plot in the volcanic arc and active continental margin fields closely resembling Middle-Late Ordovician felsic metavolcanics from the Sarrabus, Gerrei, Goceano, and Mt. Grighini units. A new U-Pb zircon age of 462.1 ± 4.3 Ma yielded by a metavolcanic layer within the Bithia Formation at Capo Malfatano must be interpreted as the emplacement age. The CL and BSE images of zircon grains do not show any evidence of interaction with late hydrothermal fluids that could have caused Pb loss and rejuvenated ages, confirming the Middle-Late Ordovician age of the metavolcanics.

2025, Applied Soil Ecology

The initial microbiological activity on the forefield of the continuously retreating Werenskiold glacier (West Spitsbergen) along the chronosequence was investigated using both culture-dependent and culture-independent approaches. The prokaryotic cell parameters: total cell number (TCN g À1 d.w.), biomass (mg C g À1 d.w.), average cell volume (ACV, mm 3 ), morphological structure (% cocci, rods, curved cells in TCN) and the contribution of viable cells with intact membrane (% in TCN) were established. The number of opportunistic bacteria (CFU g À1 d.w.) was counted using plate culture methodology. The PCR-DGGE of amplified 16S rRNA gene fragments and sequencing were also used to analyse the total (native soil samples) and culturable (plate wash samples) bacterial community structure. A total of 33 partial 16S rRNA gene sequences were obtained from the excised DGGE bands, with the majority of the sequences closely related to Actinobacteria, Bacteroidetes, and Proteobacteria (b and g) groups. A high proportion of cultured and uncultured Arthrobacter in the studied glacier foreland soil confirms their role in the initiation of soil formation processes. Changes in the structure of both the native soil samples and wash plate samples communities along the chronosequence indicated their participation in young soil formation. Although initial microbial activity is closely associated with a higher proportion of noncultivated bacteria, less numerous cultivated bacterial strains also feature significantly in the biodiversity. The main factors positively affecting TCN, BB, CFU, and the contribution of viable cells were water, nitrogen, carbon and organic matter content in the soil. In our study we have shown that a large share of the finest-particle-size fractions in the soil (dust, clay) negatively affects the BB and CFU. The native soil samples number of operational taxonomic units (OTUs) was mostly dependent on the pore water composition, and the C:N ratio in the soil, the wash plate samples number of OTUs was mostly connected with organic matter and soil water content.

2025, Journal of Geophysical Research

Deep groundwater flow can be driven by several mechanisms in sedimentary basins. In the case of evolving foreland basins, large-scale compression and thrusting could develop abnormally high pressures in the foreland sag that would initiate transient fluid flow. The so-called tectonic "squeegee" effect is thought to have caused basin-wide migration of ore-forming brines and hydrocarbons (Oliver, 1986). Two-dimensional numerical models are developed here to quantify the role of cmnpressional tectonics in driving regional fluid flow in the later stages of thrusting in a foreland basin. Poroelasticity theory coupled with regional groundwater flow form the basic elements of the mathematical model. We use the mathematical model to predict deformation and pressure dissipation in the unfaulted and nonfolded part of a foreland basin in front of a thrust belt as it is subjected to an instantaneous loading event. Sets of numerical experiments show that overpressure zones develop along the leading edge of the thrust belt near the loading front. Stress-induced flow rates of the order of centimeters to meters per year are possible soon after compression of the foreland, and transient flow fields dissipate in about 103 and 10 4 years. Longer transients can exist in very low permeability strata. Large overpressures may be unable to buildup under conditions of gradual thrusting, as fluid pressures may dissipate too quickly. The general features of tectonically driven flow are also explored through a sensitivity study to consider effects of permeability, fault and stratigraphic heterogeneity, loading magnitude, and variations in rock compressibility. The sensitivity study is based mostly on numerical experiments. As these solutions suffered from stability problems in cases where bulk rock compressibility exceeded 10 -9 Pa -! , some simple scaling arguments are used to extend the numerical results for squeezing of soft shale. One basin-specific application to the Ouachita orogen suggests that tectonic squeezing could have caused transient flow systems with relatively large flow velocities in basal Cambro-Ordovician aquifers. The volume of fluid expelled, however, is probably only a small fraction of the total brine volume needed to have formed the huge Mississippi Valley-type lead-zinc ore deposits fringing the northern margin of the Arkoma Basin on the Ozark Uplift. INTRODUCTION Groundwater flow systems evolve continuously during the development of a sedimentary basin. Transient hydraulic and thermal states evolve in response to changes in climate, thermal conditions, sediment compaction, landscape erosion, geochemical reactions, continental uplift, and tectonic stress. Understanding the transient history of subsurface fluid flow, therefore, could help elucidate the role of deep groundwater in geologic processes such as overthrusting, diagenesis, hydrothermal ore genesis, metasomatism, and petroleum migration [Bredehoeft and Norton, 1990]. In young basins there is plenty of direct evidence from drilling programs that tectonics and fluid flow play important roles in many geological and geochemical processes within subduction zones [Langseth and Moore, 1990]. In ancient basins an association among regional fluid migration, ore mineralization, and deformation of orogenic belts has been suggested by Garven and Freeze [ 1984a], Oliver [ 1986], and Bethke and Marshak [1990]. This association is particularly evident in the North American midcontinent (Figure 1). The fact that major petroleum production in North America comes from sedimentary basins associated with thrust belts suggests that there is a possible genetic relationship between thrust sheet compression and hydrocarbon migration. On the I Now at S.S. Papadopulos and Associates, Incorporated,

2025, Journal of Geophysical Research: Solid Earth

Deep groundwater flow can be driven by several mechanisms in sedimentary basins. In the case of evolving foreland basins, large‐scale compression and thrusting could develop abnormally high pressures in the foreland sag that would initiate transient fluid flow. The so‐called tectonic “squeegee” effect is thought to have caused basin‐wide migration of ore‐forming brines and hydrocarbons (Oliver, 1986). Two‐dimensional numerical models are developed here to quantify the role of compressional tectonics in driving regional fluid flow in the later stages of thrusting in a foreland basin. Poroelasticity theory coupled with regional groundwater flow form the basic elements of the mathematical model. We use the mathematical model to predict deformation and pressure dissipation in the unfaulted and nonfolded part of a foreland basin in front of a thrust belt as it is subjected to an instantaneous loading event. Sets of numerical experiments show that overpressure zones develop along the lead...

2025

The sedimentary structures in the bauxite deposits of thc Jnrnmu area are suggestive of a reworked bauxlte precursor. Trace elements and REE concentrations show that the precursor bauxite originated from the weathering of basalt. Tt means... more

2025, Tectonics

Two high‐precision leveling networks were successively surveyed in France, the NGF, measured during the 1886–1907 period, and the IGN69, measured from 1965 to 1979. The accuracy of these levelings (standard deviation of 1.8mm/√km to 3.8mm/√km) allows us to compute the vertical displacements of the benchmarks between two different eras. The results indicate the occurrence of discrete zones of uplift and subsidence: (1) a regional uplift (up to 1.4 mm/yr) of the Subalpine Massifs; (2) an important uplift of the internal Jura (up to 2 mm/yr); (3) a relative subsidence of the southern part of the Jura (0.8 mm/yr); and (4) a relative subsidence of the Bresse Basin with respect to the external Jura. Comparing the spatial distribution of zones of uplift and their respective vertical displacement rates with a regional structural cross section leads to the conclusion that present‐day uplift of the Belledonne and Bornes Massifs and of the internal parts of the Jura Mountains, can be explained...

2025, Journal of Geophysical Research: Solid Earth

Episodic GPS measurements are used to quantify the present-day velocity field in the northwestern Himalaya from the southern Pamir to the Himalayan foreland. We report large postseismic displacements following the 2005 Kashmir earthquake and several mm/yr thrusting of the central segment of the Salt Ranges and Potwar Plateau over the foreland, westward thrusting of Nanga Parbat above the Kohistan Plateau, and ~12 mm/yr SSE velocities of the Karakorum Ranges and of the Deosai and Kohistan Plateaus relative to the Indian Plate. Numerical simulations allow to determine a first approximation of slip along active faults: (1) substantial creep of ~87 mm/yr between 2006 and 2012 along the flat northeast of the Balakot-Bagh Thrust affected by the 2005 earthquake; (2) ~5 mm/yr slip of the central segment of the Salt Ranges and Potwar Plateau, whereas their western boundaries are clearly inactive over the time span covered by our measurements; (3) 13 mm/yr ductile slip along the Main Himalayan Thrust modeled by a dislocation dipping 7°northward, locked at a depth of 15 km; and (4) ~20 mm/yr slip along the shear zone forming the western boundary of Nanga Parbat, between depths of 1.6 and 6.5 km. Residuals velocities suggest the existence of left-lateral strike slip along the Jhelum Fault.

2025, Tectonophysics

Determination of relative movements between the alpine foreland and the External Crystalline Massif is a key-point for the understanding of the present-day tectonics of the western Alps. In this study we try to test the continuity of the present-day tectonics with the Mio-Pliocene deformation. In particular, we will test if the present-day displacements are localized along the thrusts of the Jura Mountains, or along a blind thrust in the Bas Dauphine ´Molasse Basin. Definition of relative movements is achieved by several methods, including a comparison of two high precision leveling networks to estimate vertical displacements, horizontal deformation measurements performed by triangulation=triangulation and triangulation=GPS comparison, in situ stress measurements performed in the different tectonic units and geomorphologic observations that constrain the location and the magnitude of the Quaternary deformation. Comparison of leveling data demonstrates: (1) an uplift of the southern Bas Dauphine ´Molasse Basin relative to its northern part (0.8 mm=year), also revealed by geomorphologic analysis, (2) a significant uplift of the most external jurassian anticlines (0.8 to 2 mm=year), also recorded by the deformation of a paleo-river bed, and (3) an important uplift (up to 2 mm=year) of the Subalpine Massifs. The horizontal strain estimated from comparison of horizontal geodetic data (triangulation, GPS) shows (1) a NW-SE directed shortening between the eastern Chartreuse Massif and the Bas Dauphine ´Molasses Basin (approximately 3 mm=year), ( ) an E-W-directed shortening in the Jura Mountains (approximately 4-3 mm=year) and (3) a dextral strike-slip motion consistent with focal mechanisms along a NNE-SSW direction between the eastern Chartreuse Massif and the eastern Belledonne Massif. These data reveal a present-day strain partitioning between the Belledonne External Crystalline Massif and the Bas Dauphine ´Molasses Basin. The westward motion of the Subalpine Massifs is partitioned along two southern jurassian thrust-folds, and a dextral NNE-SSW strike-slip shear zone between the Chartreuse Massif and the Belledonne Massif. This strain partitioning is also accompanied by a stress partitioning between the alpine foreland and the External Crystalline Massifs.

2025

r Parma . This structure represents a tectonic window in which more than 800 m of Miocene strata crop out beneath allochthonous Cretaceous to Eocene Ligurian units . In its lower part, the Miocene succession consists of Langhian marls which are onlapped- by predominantly sandstone and pebbly-sandstone strata of Serravallian age . These strata represent a good analogue of a Miocene gas-hearing reservoir discovered by a Joint Venture groep led by British Gas in an area near the Salsomaggiore structure and are generally interpreted as the proximal equivalents of the basinal turbidites forming the upper portion of the Marnoso- arenacea (Langhian to Tortonian), cropping out in the eastern part of the narthern Apennines (e .g., Ricci Lucchi, 1981) . To understand the depositional origin of 'these units and describe the lithologic characteristics of the drilled reservoirs, we integrated outcrop observations and subsurface data as an application of a more general project of collaboratio...

2025

In the continental basin-fill models, tectonically driven rejuvenation/quiescence of the hinterland, rate of basin subsidence and climate are considered as important controls of sedimentation. In applying this model-derived knowledge to the interpretation of ancient sedimentary successions, it has become common to relate the caliber of clastic sedimentary units (conglomerate, sandstone or mudstone) to the climatic or tectonic events. However, any

2025, Journal of Asian Earth Sciences

The Siwalik Group was deposited from the Mid-Miocene to the Pliocene in the foreland of the Himalaya and records the unroofing history of the mountain belt. In this study we provide the first magnetostratigraphic data for the eastern Himalayan foreland basin. We analyzed two sections of the lower to upper Siwalik Group along the Kameng River in Arunachal Pradesh, India. Magnetostratigraphic data were acquired from 395 sites within a 5.8 km-thick molassic series. Thermal demagnetization and magnetic rock-property analyses indicate a relatively low temperature (150-340 °C) Characteristic Remanent Magnetization (ChRM) yielding reliable primary directions carried by iron sulfides such as greigite. The results show local counter-clockwise rotation of the thrust sheets, which is consistent with partitioning of arc-normal and left-lateral strain along the Himalaya. Nineteen polarity zones have been identified in the two sections. Detrital fission-track data from the top and bottom of the sections are used to constrain correlations with the geomagnetic polarity time scale (GPTS) from chron C5Ar.1n to chron C2An.2n. From these results, we propose that the Siwalik Formation in Arunachal Pradesh was deposited between 13 and 2.5 Ma. The transition between the lower and middle Siwaliks is dated at about 10.5 Ma and the middle to upper Siwaliks transition is dated at 2.6 Ma. These results, coupled with sedimentological observations, suggest that the eastern Himalayan chrono-stratigraphic record is nearly synchronous with that analyzed in other parts of the Neogene Himalayan foreland basin. Nevertheless, some differences in the evolution of the sedimentation rate and in the thickness of the middle Siwaliks suggest that Indian plate flexure in the East is different from that observed in other parts of the Indian foreland basin, and could be affected by the presence of the Shillong Plateau to the south.

2025, Earth-Science Reviews

The morphological boundary between the Himalayas and the foreland plain is well expressed and most often corresponds to the frontal emergence of the Main Himalayan Thrust (MHT). This boundary is affected by surface ruptures during very large Himalayan earthquakes (Mw > 8) that regularly induce (with a recurrence of the order of 500 to 1,200 years) the uplift of the foothills relative to the plain. However, a thrust-fold system is hidden beneath the plain and is displayed by the seismic profiles of oil companies in east/central Nepal and by H/V passive geophysical techniques in Darjeeling. Its long-term kinematic evolution is slow, with a tectonic uplift of the hanging wall that is lower than the subsidence rate of the foreland basin, that is, less than approximately half a millimetre per year. During phases of low sedimentation controlled by climatic fluctuations, the morphological surfaces of the piedmont are incised by large rivers for several tens of metres; therefore, structures hidden under the sediments emerge slightly in the plain. The evolution of the hidden structures corresponds to an embryonic thrust belt mainly affected by a long-term shortening rate of 1.4 +2.5 /-1.2 mm•yr -1 , that is, 2-20% of the shortening rate of the entire Himalayan thrust system. Nonetheless, the details of the deformation associated with the embryonic thrust belt are still poorly understood. Several deformation components could affect the central Himalayan and Darjeeling piedmonts. i) Any slow steady-state deformation, such as layer parallel shortening (LPS) is not detected by Global Navigation Satellite System (GNSS) data, and such deformation would therefore absorb less than 0.5 mm•yr -1 . The geodetic data that suggest the aseismic growth of some of the structures are highly controversial. ii) For the rest of the deformation of the embryonic thrust wedge, it is yet to be proven whether deformation occurs during rare great earthquakes affecting the piedmont during medium earthquakes and/or during post-seismic deformation related to great earthquakes. The amplitude of this long-term low deformation is too limited to significantly reduce the seismic hazard in the seismic gaps of the Himalayan belt. iii) In some portions of the Himalayan front, such as Darjeeling (India), the thrust deformation related to great earthquakes propagates several tens of kilometres south of the morphological front in the zone previously affected by the long-term low deformation. It induces multi-metre surface ruptures in the piedmont and a mean shortening of 8.5 ± 6.2 mm•yr -1 . iiii) Pre-existing faults in the bedrock of the Indian craton, often oblique to the Himalayan structures, are locally reactivated beneath the foreland plain with low deformation rates.

2025, Journal of Sciences, Islamic Republic of Iran

Suture zones within continental collision zones generally considered as deep-seated thick-skinned thrusts/shear zones rotted in lower crust. Main Zagros Revers Fault (MZRF) is the suture zone for continental collision between the Afro-Arabia and Eurassia plates. The fault comprises of a main thrust in its NW part (Baneh area) while is partitioned to four fault splays in its SE part (Sharekord area). Evaluation of deformation conditions of the MZRF fault rocks carried out using quartz, feldspar and calcite twins’ microstructures as well as mineral composition indicates that the fault has propagated from various conditions correspond to different brittle to brittle-ductile transition zones. This implies localization and partitioning of deformation along strike of the Zagros suture zone. In the Baneh area, the suture zone is an emerged deep-rotted ductile zone, while in the Shahrekord area, this zone is detached at a basal detachment zone between basement and cover and then partitioned into four fault splays through its propagation to the upper structural level. This show that suture zones in orogenic belts might have changes along strike from thick-skinned to thin-skinned thrusts.

2025

The biomethane accumulation of several combinations of whey and sugarcane molasses, inoculated with sludge from a treatment facility of one of the dairy enterprises of Imbabura, was assessed in the current experiment at a concentration of 0.5 g/l COD. The whey: molasses (W: M) ratios for each treatment were 0:100, 25:75, 50:50, 75:25, and 100:0, with a constant temperature of 37°C and an initial pH adjustment of 7.5. Half a litre of total mixes was used for each treatment in duplicate. Six kinetic models were evaluated to account biomethane accumulation in anaerobic co-digestion processes in batch of whey and sugarcane molasses. Five of these have been tested by other researchers, and one was developed by modifying a first-order model to consider changes in the biomethane accumulation profile. This proposed model, along with the modified two-phase Gompertz model, resulted in the ones that were best able to adjust the experimental data, obtaining in all cases an R² ≥ 0.949, indicatin...

2025, Journal of Asian Earth Sciences

The Triassic stratigraphic framework for the Song Da and the Sam Nua basins, north Vietnam, suffers important discrepancies regarding both the depositional environments and ages of the main formations they contain. Using sedimentological analyses and dating (foraminifer biostratigraphy and U-Pb dating on detrital zircon), we provide an improved stratigraphic framework for both basins. A striking feature in the Song Da Basin, located on the southern margin of the South China Block, is the diachronous deposition, over a basal unconformity, of terrestrial and marine deposits. The sedimentary succession of the Song Da Basin points to a foreland setting during the late Early to the Middle Triassic, which contrasts with the commonly interpreted rift setting. On the northern margin of the Indochina Block, the Sam Nua Basin recorded the activity of a proximal magmatic arc during the late Permian up to the Anisian. This arc resulted from the subduction of a southward dipping oceanic slab that separated the South China block from the Indochina block. During the Middle to the Late Triassic, the Song Da and Sam Nua basins underwent erosion that led to the formation of a major unconformity, resulting from the erosion of the Middle Triassic Indosinian mountain belt, built after an ongoing continental collision between the South China and the Indochina blocks. Later, during the Late Triassic, as syn-to post-orogenic foreland basins in a terrestrial setting, the Song Da and Sam Nua basins experienced the deposition of very coarse detrital material representing products of the mountain belt erosion.

2025, Journal of Asian Earth Sciences

2025, Annales Societatis Geologorum Poloniae

This paper presents an insight into the geology of the area surrounding the ODDP proposed drilling site, and the structural development of the Carpathians in post-Palaeogene times. Since the deep drilling is proposed to be located in the Orava region of the Northern Carpathians, on the Polish-Slovak border, the structure and origin of the Neogene Orava Basin is also addressed in the paper. The outline of geology of the Carpathian Mountains in Slovakia and Poland is presented. This outline includes the Inner Carpathian Tatra Mountains, the Inner Carpathian Palaeogene Basin, the Pieniny Klippen Belt, the Outer Carpathians, the deep structure below the Carpathian overthrust, the Orava Basin Neogene cover, the Neogene magmatism, faults and block rotations within the Inner and Outer Carpathians, and the Carpathian contemporary stress field. The outline of geology is accompanied by the results of the most recent magnetotelluric survey and the detailed description of the post-Palaeogene plate tectonics of the circum-Carpathian region. The oblique collision of the Alcapa terrane with the North European plate led to the development of the accretionary wedge of the Outer Carpathians and foreland basin. The northward movement of the Alpine segment of the Carpathian-Alpine orogen had been stopped due to its collision with the Bohemian Massif. At the same time, the extruded Carpatho/ Pannonian units were pushed to the open space, towards a bay of weak crust filled up by the Outer Carpathian flysch sediments. The separation of the Carpatho/Pannonian segment from the Alpine one and its propagation to the north was related to the development of the N-S dextral strike-slip faults. The formation of the West Carpathian thrusts was completed by the Miocene time. The thrust front was still progressing eastwards in the Eastern Carpathians. The Carpathian loop including the Pieniny Klippen Belt structure was formed. The Neogene evolution of the Carpathians resulted also in the formation of genetically different sedimentary basins. These basins were opened due to lithospheric extension, flexure, and strike-slip related processes. A possible astenosphere upwelling may have contributed to the origin of the Orava Basin, which represents a kind of a rift modified by strike-slip/pull-apart processes. In this way, a local extensional regime must have operated on a local scale in the Orava region, within the frame of an overall compressional stress field affecting the entire West Carpathians. Nevertheless, many questions remain open. Without additional direct geological data, which can be achieved only by deep drilling under the Orava Deep Drilling Project, these questions cannot be fully and properly answered.

2025

The Iberian Central System, formed after the Alpine reactivation of the Variscan Iberian Massif, features maximum altitudes of 2500 m. It is surrounded by two foreland basins with contrasting elevation: the Duero Basin to the north, located at 750-800 m, and the Tajo Basin to the south, lying at 450-500 m. The deep crustal structure of this mountain range seems to be characterized by the existence of a moderate crustal root that provides isostatic support for its topography. New seismic data are able to constrain the geometry of this crustal root, which appears to be defined by a northward lower-crustal imbrication of the southern Central Iberian crust underneath this range. Contrarily to what was expected, this imbrication also affects the upper crust, as the existing orogen-scale mid-crustal Variscan detachment was probably assimilated during the Carboniferous crustal melting that gave rise to the Central System batholith. In addition, the lower crust might have thinned, allowing coupled deformation at both crustal levels. This implies that the reactivated upper-crustal fractures can reach lower-crustal depths, thus allowing the entire crust to sink. This new model can explain the differences in topography between the Central System foreland basins. Also, it provides further constraints on the crustal geometry of this mountain range, as it seems to be that of an asymmetric Alpine-type orogen, thus hindering the existence of buckling processes as the sole origin of the deformation. The results presented here have been achieved after autocorrelation of seismic noise along the CIMDEF (Central Iberian Massif DEFormation Mechanisms) profile. Although the resolution of the dataset features limited resolution (0.5-4 Hz, stations placed at ∼ 5 km), this methodology has allowed us to pinpoint some key structures that helped to constraint the deformation mechanisms that affected Central Iberia during the Alpine orogeny.

2025, Scientific Reports

The Covid-19 pandemic created havoc and forced lockdowns in almost all the countries worldwide, to inhibit social spreading. In India as well, as a precautionary measure, complete and partial lockdowns were announced in phases during March 25 to May 31, 2020. The restricted human activities led to a drastic reduction in seismic background noise in the high frequency range of 1–20 Hz, representative of cultural noise. In this study, we analyse the effect of anthropogenic activity on the Earth vibrations, utilizing ambient noise recorded at twelve broadband seismographs installed in different environmental and geological conditions in Gujarat. We find that the lockdowns caused 1–19 dB decrease in seismic noise levels. The impact of restricted anthropogenic activities is predominantly visible during the daytime in urban areas, in the vicinity of industries and/or highways. A 27–79% reduction in seismic noise ground displacement (drms) is observed in daytime during the lockdown, in popu...

2025, Geological Quarterly

Multiproxy sedimentological, gamma-spec tro met ric, foraminiferal, cal car e ous nannoplankton, and otolith data were used for the re con struc tion of the Badenian (Mid dle Mio cene) his tory of the Moravian part of the Carpathian Foredeep. The study mate rial orig i nated from the new bore hole LOM-1, which drilled >20 metres of mo not o nous clayey siltstones with ex cep tion ally rich and well-pre served microfossil as sem blages. Dis tal parts of the Carpathian Foredeep (a forebulge depozone) are exposed in this suc ces sion. Gen er ally, a quiet en vi ron ment of outer shelf to up per bathyal of mo not o nous clayey silts was in terpreted, which is typ i cal for the prox i mal parts of a pe riph eral fore land ba sin. The sec tion stud ied can be sub di vided into six in ter vals, con firm ing the cy cli cal char ac ter of Mid dle Mio cene sed i men ta tion in the Cen tral Paratethys. Interannual os cil lations of nu tri ent con tent, tem per a ture and/or sa lin ity are in ter preted based on the os cil la tions of geo chem i cal as well as palaeo bio logi cal data. The turn over con nected with the ini ti a tion of the Mid dle Mio cene Cli ma tic Tran si tion is re corded above the LO (last oc cur rence) of Helicosphaera waltrans in agree ment with pre vi ous ob ser va tions in the Carpathian Foredeep. The changes in clude cool ing, a de crease in nu tri ents, a prob a ble in crease of the sa lin ity of sur face wa ter, and in crease of sea son al ity. Sea son al ity was man i fested by an al ter na tion of mixed and strat i fied wa ter col umns with a sea sonal in put of nutri ents. Con cern ing nu tri ents, sources of sea sonal riverine in put or sea sonal upwelling are both pos si ble.

2025, Tectonics

This paper sheds light on the evolution of the Patom belt. This mountain range draws an arc along the south-eastern edge of the Siberian craton. It is supposed to be of Caledonian age and to result from the accretion of microcontinents against the craton, but up to now, its detailed stratigraphic and tectonic history was unclear. A field study allows us to precise it. The sedimentary record is marked by a slow evolution with stable periods of more than 250 Ma. The observed sedimentary succession confirms the existence of a passive margin setting in the Late Riphean (900 Ma), followed during the Vendian (650-600 Ma) by the obduction of the Baikal-Muya ophiolites belt and a foredeep inversion. After then, a late Cambrian extension occurred, which is first described in this paper. The second collision stage occurred after 385 Ma, in the late Devonian-Early Carboniferous. Sedimentary and tectonic data are interpreted in the light of the geodynamic evolution of Siberia, which is dominated by continental collages against the Siberian craton. Field data reveal a homogeneous direction of compression from the inner areas to the foreland. Whereas the inner range displays metamorphosed units deformed in the ductile domain, deformation is weaker in the foreland, which developed above the cratonic crust. We relate this high deformation gradient to the presence of the stiff craton which impeded strain propagation. The irregular shape of the craton as well as pre-existent basement topography can explain the different tectonic styles observed along the belt.

2025, International Journal of Geosciences

The following paper presents an integrated geological (field observations, wells data) and geophysical data (Gravity measurements and seismic profiles) in Tellian foreland domain of the northeastern Tunisia (Mateur plain) served for a new proposed structural map with many faults already recognized or supposed by traditional structural studies and highlights major regional accidents.

2025, Iraqi Journal of Science

The study area is situated in the northern part of the Arabian Plate. The evolution of the Zagros Foreland basin is related to the compressional tectonic system at the beginning of the Tertiary Period. This study gives an adequate nomenclature for the Oligocene – Early Miocene Sequence is Missan Group. The Buzurgan Oilfield was chosen to represent the stratigraphic column corresponding to that period. These sediments were subdivided into two cycles, where each one ends by a sequence boundary, equivalent to the lowstand siliciclastic residues in the basin center. The first cycle, Paleocene-Oligocene Epoch, was deposited marly limestone with planktonic foraminifera in the basin center during the transgressive and highstand conditions. The Lower Missan Group was deposited during the latest Oligocene lowstand conditions and overlaid the deep marine Oligocene sediments. The second cycle represented the Early Miocene Epoch (Aquitanian), by which the Euphrates Formation was deposited...