Deformation Events Research Articles

Evaluating the Relation of Cave Passage Formation to Stress-Field: Spatio-Temporal Correlation of Speleogenesis with Active Tectonics in Asprorema Cave (Mt. Pinovo, Greece)

Caves serve as time capsules, preserving significant markers of tectonic activity and offering insights into geological history. Fault geometries and past activations found in caves can be correlated with known deformational events in the broader area, temporally delimiting the speleogenesis. More specifically, cave passage formation is suggested to be affected by the regional stress-field. The Asprorema Cave in Northern Greece is a typical example of a fracture guided cave, with passage geometry influenced by relative sidewall movements, revealing these discontinuities as faults. This study constructs the timeframe and conceptual model of speleogenesis in relation to tectonic events, geomorphological evolution and hydrological zones, and verifies its relation to the stress-field. Active tectonics, mineralogy and cave geomorphology are investigated. Results suggest syntectonic speleogenesis under phreatic and epiphreatic conditions. The absence of corrosion on fault slip surfaces implies recent activations post cave’s shift to the vadose zone. Structural analysis identifies three main neotectonic phases: NNW-SSE striking faults (oldest group of structures), NE-SW striking faults with dextral strike-slip movement (post-middle Miocene), and NE-SW striking normal faults indicating extensional stress-regime (Quartenary). The last two phases affect cave passage shape causing wall displacement, highlighting passage formation along discontinuities perpendicular to the horizontal minimum stress axis.

The Protracted Evolution of a Plate Boundary: Eastern Cuba Block and Old Bahamas Channel

AbstractThe Eastern Cuban block has experienced a complex tectonic history characterized by plate interactions, resulting in a diverse array of geological features observable in the offshore sedimentary record. We investigate the tectonic evolution of offshore Eastern Cuba, specifically in the Old Bahamas Channel and its surrounding areas, by integrating multi‐channel seismic (MCS) reflection and published geological data. Our analysis employs stratigraphic frameworks and MCS data to assess deformation and key geological events in the region. We highlight the complex tectonic history of the Eastern Cuban block, marked by significant geodynamic events, such as rifting, the subduction of the oceanic Proto‐Caribbean plate, and syn‐orogenic and post‐orogenic phases. The seismic units observed in the majority of the study area reveal the early evolution of the Northern Proto‐Caribbean margin, subsequently impacted by the Cuban orogeny and the reactivation of the Cuban Transform Fault zone corresponding to a former plate boundary. We propose estimated ages for the seismic sequences, correlating them with available well data from neighboring regions. This study offers valuable insights into the tectonic history and geological evolution of offshore Eastern Cuba, contributing to a more comprehensive understanding of the region's geodynamic development.

The power of modern 3-D visualization of high-resolution terrain models in geologic mapping: Complex fold geometries revealed by 3-D mapping in the Panamint metamorphic complex, eastern California, USA

We use structure from motion–multiview stereo (SM) terrain models developed from ground-based images and images acquired from uncrewed aircraft (aka drones) as a base map for three-dimensional (3-D) mapping on the walls of a deep canyon in the Panamint Range of eastern California, USA. The ability to manipulate the 3-D model with views from arbitrary look directions and broad scale range revealed structures that were invisible to conventional two-dimensional (2-D) mapping because of both the scale of the structures and their exposure on vertical to near-vertical cliff faces. The analysis supports field evidence for four phases of ductile deformation, with only one of the younger phases documented on early geologic maps of the area. The oldest deformational event (D1) produced the main metamorphic fabric and pre-dates Late Cretaceous plutons. This deformation produced a 200–250-m-thick high-strain zone localized along marbles at the top of the Kingston Peak Formation and lower Noonday Formation. Geometric analysis from the model suggests strongly that large sheath folds at scales of 100–300 m are developed within these marbles. Large measured finite strains indicate displacement across this apparent shear zone of at least 4–5 km and displacements of tens of kilometers are allowable, yet the structure is invisible to conventional mapping because the high-strain zone is stratabound. The main fabric shows two clear overprints and a third that is likely an even younger deformation. D2 and D3 generated tight to close, recumbent folds and open to tight, upright folds, respectively, both folding the main foliation with localized development of crenulation cleavages axial planar to the folds. An additional overprint shows no clear cross-cutting relationship with D2 or D3 fabrics and could be a manifestation of either of those events, although the deformation is spatially limited to a narrow shear zone beneath a brittle, dextral-normal fault with the same kinematics as a mylonitic fabric in a Cretaceous granite in the footwall. This observation suggests an extensional, core complex–style deformation to produce this structure. We suggest that 3-D mapping has the potential to revolutionize geologic mapping studies, particularly where steep topography provides 3-D views that are virtually invisible on conventional 2-D maps. Previously bewildering geologic puzzles can be solved by the ability to visualize large cliff exposures from arbitrary angles and map the features in true 3-D at resolutions to the centimeter level. Although this study emphasized intermediate scales imaged by a drone, our methods here are easily extended to larger scales using a crewed aircraft for imaging. We suggest these methods should be used routinely in frontier areas with steep terrain where aviation is already in use for access, but the methods can be employed anywhere steep terrain “hides” major rock exposures on conventional 2-D maps.

Uncertainty Analysis of Post-Failure Behavior in Landslides Based on SPH Method and Generalized Geotechnical Random Field Theory

In slope stability analysis, the inherent heterogeneity and spatial variability of soil significantly influence the aftermath of landslides, including critical aspects like runout distance, influence distance, and volume. This research integrates Smoothed Particle Hydrodynamics (SPH) with random field theory to precisely model the large deformation events in slopes with anisotropic shear parameters, while leveraging Graphics Processing Unit (GPU) parallel computing to expedite the generation of random field samples and SPH simulations. This approach meticulously examines how spatial heterogeneity of soil affects slope instability, simulating soil parameters across varied geological settings. It considers the fluctuation scale of anisotropy, the cross-correlation of cohesion and the angle of internal friction, along with their coefficient of variation (CV), to elucidate their impact on landslide magnitude and severity. This study furnishes a robust tool for a holistic assessment of slope impacts and landslide volumes. Additionally, by delineating the computational efficiency disparities between GPUs and Central processing units (CPUs), it underscores the pronounced efficiency benefits of GPU computing. The insights garnered offer fresh perspectives and methodologies in slope stability analysis and disaster risk evaluation, contributing to the finer prediction and management of this prevalent and grave geological hazard.

Multistage evolution of gold mineralization in the Kibali gold district: Insights from pyrite analyses

The Kibali gold district, located on the Congo Craton, comprises a Neoarchean gold resource exceeding 28.7 Moz. The district is located within a westerly-verging stacked fold-and-thrust belt associated with a compressional tectonic regime active from ca. 2.64–2.60 Ga. Deposits are hosted by a major fault zone that consists of a complex series of smaller thrust faults, shear zones, and folds, which extend over 60 km. Gold deposits are primarily hosted in BIF and clastic sedimentary rocks. The gold and associated sulfides are in veins and disseminated in NE-to NNE-trending ore shoots within the deformed and metamorphosed volcanosedimentary rocks. Pyrite is the dominant sulfide mineral and hosts both solid solution gold and free gold. Because of its strong association with the gold mineralization, our study focusses on unravelling the metallogeny of the area by considering pyrite textural analyses, in situ trace element analyses using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), and S isotopic composition (δ34S) analyses using Secondary Ion Mass Spectrometry (SIMS).Eight distinct pyrite types were identified, including microcrystalline sooty (py-0a), small grains (<40 μm) (py-0b), aggregate recrystallized (py-1), core-rich inclusion (py-2), vein-like (py-3), non-zoned (py-4a), oscillatory As-bands zoned (py-4b), and cubic euhedral (py-5) pyrite. The ore-forming processes occurred over a polyphase evolution. Syn-diagenetic pyrite py-0a in volcaniclastic layers of older basin sediments served as the primary repository of Au (15.6 ppm median) with a near-zero δ34S value. Late diagenetic or early metamorphic pyrite (py-0b) was found in younger basin sediments. Py-1 resulted from solid-state recrystallization of py-0a and py-0b. During the early ore stage, porous py-2 with high Au concentrations (3.1 ppm) and various trace element enrichments precipitated due to fluid-rock interaction. Metal precipitation occurred through sulfidation and carbonation of wall rock with a relatively reduced fluid undergoing 34S-depletion. However, py-3 displayed notable trace element depletion and a complex mineral association. In a second ore stage, py-4a and zoned py-4b deposition occurred, dominated by an over-pressured fluid fracturing brittle rock. Py-4b, rich in Au (5.5 ppm) concentrated in oscillatory zoned As-rich bands, resulted from interactions during pulsed fluid flow. This process involved fluid phase separation, non-equilibrium conditions, 32S-depletion, and precipitation of py-4b with a high δ34S value (6.4 ‰ mean). Subsequently, pyrite (0–4) generations underwent deformation during a later ductile deformation event, leading to the remobilization and concentration of invisible gold into adjacent gold grains within the high-grade shoot plunging NE. This process involved shearing, boudinaging, and folding ore minerals in tightly folded structures. Late-stage py-5 formed under gold-poor fluid conditions or inefficient gold depositional conditions. Brittle fracturing of these grains later provided local sites for remobilized gold. The study contributes insights into the origin and evolution of gold mineralization in the Kibali gold district, supporting a multistage ore-forming fluid system.

THE ARABIA – EURASIA COLLISION ZONE IN IRAN: TECTONOSTRATIGRAPHIC AND STRUCTURAL SYNTHESIS

The Arabia – Eurasia collision zone in the central part of the Alpine – Himalayan orogenic system has had a complex deformation history since the Palaeozoic. In Iran, the collision zone consists of the Alborz‐Talesh, Kopeh Dagh and Zagros foldbelts and the intervening Central Iran area. In this review paper, we summarize the structural architecture and tectonostratigraphic characteristics of these domains and attempt to correlate regional deformation events between them. The results show that six regional‐scale deformation phases can be recognized and correlated in Iran over a time interval extending from the Late Palaeozoic to the Late Cenozoic.Late Palaeozoic rifting in northern Gondwana and subsequent oceanic spreading resulted in the separation of the Central and North Iran blocks from the Arabian Platform. These blocks later converged and collided with the southern margin of Eurasia due to the subduction of the intervening PalaeoTethys lithosphere (“Cimmerian orogeny”: Late Triassic). The convergent setting resulted in the initial development of the Alborz‐Talesh foldbelt in present‐day northern Iran, while extensional basins developed in the forebulge area in Central Iran. Continuing northward subduction of NeoTethyan oceanic lithosphere at the southern Eurasia margin produced Early Cretaceous back‐arc extension and associated volcanism in Central Iran and the Alborz‐Talesh area to the north. A phase of compressional deformation in the Late Cretaceous was related to the collision of a series of microcontinents derived from Northern Gondwana, including the Ercinjan and Bitlis massifs, with the Central Iran block, and is recorded in the Alborz‐Talesh foldbelt and in Central Iran. Further back‐arc extension in the late Paleocene – Eocene was accompanied by pervasive volcanism and volcaniclastic sedimentation throughout northern and Central Iran. The final closure of NeoTethys and convergence between the Arabian and Eurasian Plates evolved through phases of early Oligocene “soft” collision and middle Miocene “hard” collision. This was accompanied by thrusting in the internal parts of the Zagros foldbelt and by folding and subordinate thrusting in the more external parts, with related development of the flexural Mesopotamian Basin in the foreland to the SW.

Age, Kinematic and Thermal Constraints of Syn‐Orogenic Low‐Temperature Deformation Events: Insights From Thermochronology and Structural Data of the Nekézseny Thrust (Alpine‐Carpathian‐Dinaric Area)

AbstractUnraveling the age and kinematics of low temperature deformation events is crucial in understanding the late‐stage evolution of orogens. However, accurate age constraints can often be challenging to obtain due to unideal outcrop conditions, large sedimentary hiatuses or the lack of well‐defined thermal events. In this study, we show on the example of the Nekézseny Thrust, a poorly exposed late orogenic thrust in the southern Western Carpathians, that a combined approach of structural analysis and multi‐method thermochronology can provide the necessary temporal, kinematic and thermal constraints for a detailed reconstruction of the deformation history. While structural mapping revealed that the Late Cretaceous Uppony Gosau Basin in the footwall of the Nekézseny Thrust underwent a significant post‐Campanian and pre‐Miocene shortening, K/Ar dating of fault gouge samples from the main fault zone constrained the primary thrusting event to the Maastrichtian. Based on the acquired apatite fission‐track and (U‐Th)/He ages, subsequent heating of the Upper Cretaceous sediments due to tectonic burial was limited to 75–100°C, followed by deformation‐related and gradual cooling between the Eocene and Early Miocene. Considering the reconstructed deformation history, as well as the large‐scale tectonic affinity of the displaced units in its footwall and hanging wall, the Nekézseny Thrust is a far‐traveled (ca. 600 km) segment of the Late Cretaceous Alps‐Dinarides contact zone, whose development was linked to the switch from lower plate to upper plate position with respect to the Sava Zone and Alpine Tethys sutures, respectively.

The Zaozigou orogenic gold-antimony deposit, West Qinling Orogen, China: Structural controls on multiple mineralization events

Orogenic gold deposits are generally thought to represent one perhaps protracted event. However, recent research on orogenic gold deposits increasingly offers evidence for some deposits forming through multiple and clearly discreet hydrothermal episodes. The giant Zaozigou orogenic Au-Sb deposit in the Triassic to Cretaceous West Qinling Orogen, central China, includes both steeply dipping and gently dipping orebodies. The two distinct mineralization styles provide a valuable setting for investigating a multiple mineralization model by integrating structural analysis within a robust geochronological framework. Through fieldwork and geochronology, we define a progression of major tectonic events in the area of the Zaozigou deposit. The deposit is hosted within a well-bedded sequence of Early Triassic metasedimentary rocks of the South Qinling Terrane. Pre-mineralization E-W shortening (D1) during subduction of the Mianlue oceanic slab include folding with resulting axial planes striking N-S, emplacement of Triassic ENE-striking and WNW-striking dacite dikes accompanied by Middle Triassic greenschist facies metamorphism. Late Triassic gold-stibnite quartz vein and disseminated mineralization formed along ENE-striking and steeply dipping D2 brittle to ductile sinistral faults. Their orientations suggest a link to the regional NNE-SSW maximum principal stress coinciding with transpression caused by the Late Triassic collision between the South China Block and South Qinling Terrane. Overprinting Early Cretaceous quartz-stibnite veins developed along gently dipping (20° to 40°) brittle D3 normal fault zones, which exhibit a NE-SW minimum principal stress. This younger deformation event is interpreted to be related to the Early Cretaceous tectonic transition from shortening to extension of the West Qinling Orogen. Therefore, the Zaozigou deposit reveals a model of multiple orogenic gold mineralizing events, with migration of hydrothermal fluids during discrete deformation episodes and the resulting formation of a single composite deposit formed along overprinting structures at separate times of orogenesis.

Tectonic Evolution of the Eastern Southern Alps (Italy): A Reappraisal From New Structural Data and Geochronological Constraints

AbstractThe Eastern Southern Alps fold‐and‐thrust belt (ESA) is part of the seismically active S‐verging retro‐wedge of the European Alps. Its temporal tectonic evolution during continental shortening has so far been constrained by few and low‐resolution indirect time constraints. Aiming at better elucidating the ESA spatiotemporal evolution, we gathered new structural and geochronological data from two regional thrust systems: the innermost south verging Valsugana Thrust (VT) and the more external Belluno Thrust System (BTS). Field work allowed us to constrain the geometry and kinematics of those thrusts and related folds and informed our sampling strategy to carry out fault gouge K‐Ar and tectonic carbonate U‐Pb dating from representative samples structurally associated with the VT and BTS. Our results suggest that the VT was active already in the Late Cretaceous (between ∼78 and 76 Ma) in response to far‐field stresses, with repeated reactivation continuing to the Late Miocene (∼6 Ma). The BTS recorded two distinct deformation events during the Oligocene (∼30 Ma) and at the Oligocene‐Miocene boundary (∼23 Ma). The VT was active for ∼72 Myr and partly acted during out‐of‐sequence thrusting. Based on regional correlations, we propose that the ESA share a similar spatiotemporal deformation history with the central Southern Alps farther to the west. We suggest a conceptual regional tectonic model wherein multiple, broadly coeval deformation events occurred in the entire Southern Alps during their long‐lived orogenic deformation in response to generally continuous NW‐SE shortening.

Ground deformation due to natural resource extraction in the Western Canada Sedimentary Basin

The study links multiple natural resource extraction activities in the Western Canada Sedimentary Basin (WCSB) with observations of ground deformation. Sentinel-1, RADARSAT-2, and RADARSAT Constellation Mission (RCM) Synthetic Aperture Radar (SAR) data acquired as early as 2015 were used to compute deformation maps and ground deformation time series. Ground deformation produced by induced earthquakes (2015 Mw 4.6 in British Columbia and 2022/23 Mw 5.1/4.6 in Alberta; and 2017/18 Mw 5.0/4.2 slow slip events in British Columbia) were mapped with individual interferograms. Long-lasting ground deformation due to Steam-Assisted Gravity Drainage (SAGD) and Cyclic Steam Stimulation (CSS) enhanced oil recovery and coal and potash underground mining were mapped with the Multidimensional Small Baseline Subset (MSBAS) time series method. When both ascending and descending data were available, MSBAS was used to compute two-dimensional (2D) deformation time series and rates. It was observed that seismic and aseismic ground deformation due to hydraulic fracturing and saltwater injection in WCSB had a similar surface expression (paired anomaly), spatial extent (5-10 km) and orientation (striking NW-SE), suggesting that triggering processes might be technogenic. In the case of hydraulic fracturing, ground deformation appeared soon after the beginning of the operation, while not with saltwater injection, as it took years. The source mechanism of the 2015 Mw 4.6 earthquake was obtained through inverse modelling of the two descending interferograms. The rectangular source model corresponded to a fault at 1.98 ± 0.09 km depth, with 126° ± 7° strike, 14° ± 2° dip, 72° ± 7° rake, 1.61 ± 0.24 km width, 2.54 ± 0.23 km length, and 0.19 ± 0.07 m slip. In the case of in-situ enhanced oil recovery, ground deformation varied significantly depending on the technique. Continuous uplift observed at the SAGD site had a rate of only about 0.05 m/year, while reversible uplift and subsidence at CSS sites exceeded 0.2 m/month, even though wells in both cases were located at approximately similar depths (380 m for SAGD vs 520 m for CSS). In the case of underground mining, the spatial extent of subsidence depended on the extraction depth (200-500 m for coal vs 1000 m for potash). When a mining operation was conducted in an area with topographic relief, horizontal deformation was observed in addition to subsidence. Various observed deformation signals may precede more consequential deformation events.

Early Proterozoic Polymigmatites in a Zone of Granulite Metamorphism: P–T–X Conditions, Age, and Duration of Migmatization (Northern Ladoga Area, Russia)

Abstract —Polymigmatites in the Early Proterozoic metamorphic complex of the Northern Ladoga area trace the evolution of thermodynamic conditions during anatexis. The P–T conditions inferred for anatectic leucosome correspond to the onset of partial melting under granulite facies conditions of 5.5–6.2 kbar and 720–810 °C. After the peak of metamorphism, pressure and temperature show a coupled decrease to 4 kbar and ~550 °C, respectively. The latest granitic veins were intruded into metamorphic rocks during an event of brittle deformation. The P–T trend correlates with changes in migmatitic mineral assemblages and in chemistry of minerals. Newly formed leucocratic material changed from plagiogranitic to granitic composition when melting involved plagiogneiss but melt derived from Al-rich metapelite remained granitic. The analyzed leucosomes and granitic veins originated by multistage melting, under P–T conditions changing from granulite to amphibolite facies, between 1875 and 1865 Ma. Judging by their ages, the leucosome and granitic vein bodies from the Lakhdenpokhia and Priozersky zones of the area differed in the total duration of crystallization. Therefore, a single thermal event involving different lithologies can produce intrusions of different ages.

Structural, 40Ar/39Ar Geochronological and Rheological Feature Analysis of the Guoxuepu Shear Zone: Indications for the Jitang Metamorphic Complex in the Northern Lancangjiang Zone

AbstractThe Jitang metamorphic complex is key to studying the tectonic evolution of the Northern Lancangjiang zone. Through structural‐lithological mapping, structural analysis and laboratory testing, the composition of the Jitang metamorphic complex was determined. The macro‐ and microstructural analyses of the ductile detachment shear zone (Guoxuepu ductile shear zone, 2–4 km wide) between the metamorphic complex and the overlying sedimentary cap show that the shear sense of the ductile shear zones is top‐to‐the‐southeast. The presence of various deformation features and quartz C‐axis electron backscatter diffraction (EBSD) fabric analysis suggests multiple deformation events occurring at different temperatures. The average stress is 25.68 MPa, with the strain rates (έ) ranging from 9.77×10–14 s–1 to 6.52×10–16 s‐1. The finite strain of the Guoxuepu ductile shear zone indicates an elongated strain pattern. The average kinematic vorticity of the Guoxuepu ductile shear zone is 0.88, implying that the shear zone is dominated by simple shear. The muscovite selected from the protomylonite samples in the Guoxuepu ductile shear zone yields a 40Ar‐39Ar age of 60.09 ± 0.38 Ma. It is suggested that, coeval with the initial Indo–Eurasian collision, the development of strike‐slip faults led to a weak and unstable crust, upwelling of lower crust magma, then induced the detachment of the Jitang metamorphic complex in the Eocene.

The Magnetopause Deformation Indicated by Fast Cold Ion Motion

AbstractThe magnetopause deformation due to the upstream magnetosheath pressure perturbations is important to understand the solar wind‐magnetosphere coupling process, but how to identify such events from in situ spacecraft observations is still challenging. In this study, we investigate magnetopause crossing events with fast‐moving cold ions in the magnetosphere from Magnetospheric Multiscale observations, and find when fast‐moving cold ions are present at the magnetopause, they are closely associated with the magnetopause deformation, which is featured by fast magnetopause motion and significant magnetopause normal deflection from model predictions. Therefore, fast‐moving cold ions can be a useful indicator to search for magnetopause deformation events. By integrating the cold ion speed, the inferred magnetopause deformation amplitude varies from 0.1 to 2.0 RE. Further statistics indicate that such magnetopause deformation events prefer to occur under quasi‐radial interplanetary magnetic field and fast solar wind conditions, suggesting high‐speed magnetosheath jets could be one direct cause of magnetopause deformations.

Shock features in carbonates from CM carbonaceous chondrites

We have investigated different carbonate minerals (calcite, aragonite, and ankerite) from two meteorites with different shock metamorphic stages (Boriskino, CM2 − ∼ S3-S4 and Murchison CM2.5–2.2 − S1-S2) using various electron microscope techniques. Our detailed transmission electron microscopy study shows that carbonates are valuable recorders of the shock metamorphic environment and help interpret shock metamorphic conditions on the chondrite parent asteroids. We show the occurrence of fine-scale complex microstructures (dislocations, modulations, mosaic blocks, and microfractures) in all carbonates analyzed, indicating that they were modified during deformation processes at a variable degree. The presence of shock features in all generations of carbonates (Type 0, 1, and 2) indicates that shock deformation event/(s) occurred after the precipitation of all types of carbonates. In Boriskino, the most shocked meteorite analyzed, carbonates record very distinct microstructures compared to Murchison, an unshocked or very weakly shocked sample. We divided these microstructures into two different categories as a function of the degrees of deformation, and several features could be used as diagnostic tools for low and high shock pressures in meteorites. Deformation features are pervasive in calcites, aragonites (Type 1 and 2 Ca carbonates), and ankerites from Boriskino. However, the abundance and distribution of these deformation features are minimal in all calcite crystals analyzed from Murchison and one Type 0 Ca carbonate from Boriskino. This suggests the presence of a correlation between these microstructural features and the degree of shock metamorphic stages of the samples analyzed. The low amount of deformation features in the Type 0 calcite from Boriskino could indicate that the least altered lithologies from Boriskino were not subject to high-intensity impacts.

From early Paleozoic subduction to end-Carboniferous post-orogenic collapse: New constraints on the tectonic evolution of the Central and South Tianshan (NW China)

Recognition of extensional events during orogenesis is critical for the reconstruction of geodynamic evolution of orogens, but is also a challenge due to multi-stage tectonic superimpositions. The South Tianshan is the southern margin of the Paleozoic Central Asian Orogenic Belt (CAOB) and a key for understanding the geodynamic evolution of the CAOB. Here we present new structural, geochronological and geochemical data for the Paleozoic sedimentary, igneous and metamorphic rocks in the Central and South Tianshan (NW China). Based on our new results and published data, we suggest that a neritic to terrestrial back-arc basin existed to the south of the Central Tianshan magmatic arc during the Early-Middle Devonian. We document a crustal anatectic event (∼304 Ma) associated with peraluminous granitic magmatism (∼305–295 Ma) in the South Tianshan. Multi-stage ductile deformation events witnessed the Paleozoic evolution from subduction-accretion to post-orogenic collapse of the Tianshan Orogen: (1) Late Devonian-Carboniferous regional top-to-the-north ductile shearing is related to the southward subduction of the South Tianshan back-arc basins; (2) late Carboniferous south-verging folds and brittle-ductile axial-plane cleavages correspond to back-thrusting resulted from the collision between Central Tianshan and Tarim; (3) latest Carboniferous ductile normal faults developed in migmatites define a dome-like structure linked with syn-anatectic exhumation of the middle crust during the post-collisional extension; and (4) regional dextral strike-slip faulting attributed to Permian lateral extrusion. Therein, two stages of crustal extension are key puzzle pieces to reconstruct the accretionary orogenic processes of the Paleozoic Tianshan.

Fluid Flow, Mineralization and Deformation in an Oceanic Detachment Fault: Microtextural, Geochemical and Isotopic Evidence From Pyrite at 13°30′N on the Mid‐Atlantic Ridge

AbstractHydrothermal fluids in ultramafic‐hosted hydrothermal systems associated with oceanic detachment faults can be more oxidizing compared to mafic‐hosted vent sites. These fluids form a mineral assemblage of pyrite, magnetite and hematite. At 13°30′N on the Mid‐Atlantic Ridge, chlorite‐quartz breccias recovered from an exposed fault scarp contain pyrite, with abundant magnetite and hematite, indicating that the redox of the fluids was variable. In primary micron‐scale zonations in pyrite, Ni, Co, and Se have a decoupled relationship, recording fluctuations in the chemical composition and temperature of hydrothermal fluid as the grains grew. Secondary zonations that erase and overprint primary zonations are limited to the grain margin and permeable regions within the grain core. Secondary zonations formed via two processes: (a) grain dissolution followed by overgrowth, and (b) remobilization of metals during oxidizing fluid flow events. In both instances, Ni and Co have been mobilized and concentrated, and are not lost to the hydrothermal fluid. Superimposed on these features is evidence of grain scale deformation related to periods of fault movement along the detachment surface. Sulfur isotope ratios (δ34S) in pyrite systematically decrease from the grain margin to the grain core, indicating that increased amounts of sulfur were derived from thermochemical sulfate reduction of seawater. Thus, pyrite records the evolution of fluid flow and deformation events during exhumation along the detachment surface from ∼1 to 2 km below the seafloor at the base of the lava pile, with temporal fluctuations in fluid redox identified as an important process in controlling Ni and Co enrichment in pyrite.

Comprehensive Insights into Eosinophil Interactions in Sickle Cell Anemia Severity

Sickle Cell Anemia (SCA) is a prevalent inherited blood disorder characterized by abnormal hemoglobin leading to erythrocyte deformation and consequential vaso-occlusive events. While the primary focus has traditionally centered on the role of red blood cells in SCA pathophysiology, recent investigations have unveiled the intricate involvement of eosinophils in modulating disease severity. Eosinophils, classically recognized for their role in parasitic infections and allergic responses, have emerged as significant contributors to the inflammatory milieu and vascular dysfunction observed in SCA. This paper aims to provide an extensive understanding of the multifaceted interactions between eosinophils and the pathogenesis of sickle cell anemia, emphasizing their impact on disease severity. Insights into eosinophil biology, including their cytokine release profile, granule protein activity, and endothelial interactions, underscore their dual role in both propagating and modulating inflammation in the context of SCA. The complex interplay between eosinophils and the inflammatory microenvironment in SCA dictates disease severity, warranting a deeper understanding of these interactions for the development of targeted therapeutic strategies. In conclusion, this comprehensive review consolidates current knowledge regarding eosinophil involvement in sickle cell anemia severity, emphasizing the necessity for further investigations into specific eosinophilic mechanisms. A deeper comprehension of eosinophilic contributions to SCA pathophysiology presents a pathway toward novel therapeutic modalities, ultimately enhancing the management and prognosis of individuals afflicted with this challenging hematologic disorder.

Origin of calcite cements in the Permian Lucaogou Formation tight reservoirs, Jimsar sag, Junggar basin, NW China: Constraints from geochemistry

Understanding the diagenetic evolution of carbonate cementation in hydrocarbon reservoirs is critical to better reconstruct the history of fluid flow during petroleum accumulation. The extensive occurrence of carbonate cements within the lower Permian Lucaogou Formation tight reservoirs is regarded as a major diagenetic factor that causes strong hydrocarbon reservoir heterogeneities. Petrographic and geochemical analyses, including optical microscopy fitted with cathodoluminescence, scanning electron microscopy, carbon and oxygen stable isotopes, in situ rare earth element, as well as fluid inclusion microthermometry, were carried out to decipher the origin of calcite cementation and understand its control on reservoirs quality. Petrography shows that the precipitating cements mostly consist of pore-filling blocky/mosaic calcite, with a dull orange luminescence color. Chondrite-normalized rare earth element (REE) patterns and C–O isotopic compositions of these calcite cements exhibit strongly negative Eu and Tb anomalies, enrichment in light REE, positive carbon (δ13CPDB = 0.58‰–7.45‰) and negative oxygen (δ18OPDB = −11.38‰ to −8.61‰) isotopic values, similar to the dolostone and micritized peloidal grains, suggesting that the calcite-precipitating fluids were derived from dissolution of lacustrine depositional carbonates. The relative timing of calcite precipitation in reservoirs was constrained based on the thermal-burial history of the study region and precipitation temperatures obtained from fluid inclusions. The results show that this cementation episode mainly occurred during the Late Triassic to Early Jurassic, which was synchronous with the tectonic uplift event. Moreover, homogenization temperatures of fluid inclusions and geochemical signatures of the calcite cement are similar to those of the fracture-fillings, suggesting that these two calcite phases may be genetically related and form coevally within one fluid flow system. It can be interpreted as a response to the compressional tectonic deformation given by the collision of the Qiangtang Block with the Eurasia Plate. This tectonic deformation event is regarded as the driver for calcite precipitation during the early burial stage, resulting in a considerable reduction of reservoir quality. Calcite cementation is pervasive and may play a main role in halting hydrocarbon migration through some of the permeable pathways in reservoirs.

Exploring the impact of fracture interaction on connectivity and flow channelling using grown fracture networks

Quantitative assessment of the flow properties and mechanical stability of naturally fractured rock is frequently practised across the mining, petroleum, geothermal, geological disposal, construction and environmental remediation industries. These fluid and mechanical behaviours are strongly influenced by the connectivity of the fracture system and the size of the intact rock blocks. However, these are amongst the more difficult fracture system properties to characterize and honour in numerical simulations. Nonetheless, they are still the product of interactions between fractures that can be conceptualized as a series of deformation events following geomechanical principles. Generating numerical models of fracture networks by simulating this deformation with a coupled and evolving rock mass and stress field is a significant undertaking. Instead, large-scale fracture network models can be ‘grown’ dynamically according to rules that mimic the underlying mechanical processes and deformation history. This paper explores a computationally efficient rules-based method to generate fracture networks, demonstrates how different types of fracture patterns can be simulated, and illustrates how inclusion of fracture interactions can affect flow and mechanical properties. Relative to methods without fracture interaction and in contrast to some other rules-based approaches, the method described here regularizes and increases fracture connectivity and decreases flow channelling.

SYNERGY OF ADVANCED PROCESSING TECHNIQUES USING COPERNICUS SAR AND OPTICAL SATELLITE IMAGERY TO DETECT GROUND DISPLACEMENTS: THE CASE STUDIES OF PYRGOS AND PAREKKLISIA VILLAGES IN CYPRUS

Abstract. Cyprus has a long history of destructive tectonic activity and related geohazards. This is mainly due to its location on the Mediterranean fault zone and the interaction of the Eurasian and African plates. To study the occurrence of land displacements on a national scale, various space-based monitoring techniques exploiting the Copernicus program’s datasets were studied using Sentinel-1 and Sentinel-2 satellite images for the period of 2016–2021. More specifically, differential spectral indices were calculated by subtracting the reference 2016 Sentinel-2 image from an image for every year until 2021, and a parallelised version of Persistent Scatterer Interferometry (PSI) was conducted using a time series of Sentinel-1 data over the same period, to identify ground displacements over time. The PSI analysis in the area around Pyrgos and Parekklisia villages, detected Line-of-Sight (LoS) uplift phenomena of a maximum rate of 8 mm/y, in ascending and descending Sentinel-1 satellite passes. Similarly, deformation was identified from optical image processing. The integration of both techniques provided qualitative and quantitative information about ground deformation events in both areas, showcasing a complementarity of results obtained, with PSI detecting displacements in urban/built-up areas, and multispectral change detection in rural environment. In terms of correlation, the two techniques showed a fit of 31.34% in ascending and 26% in descending pass, providing additional information on the size of affected areas. This synergistic approach facilitates the systematic monitoring of areas of interest, providing significant and timely information to decision-makers, to take actions and adopt protective measures when and where it is required.