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Geological formations with fractures are frequently encountered in various research fields. Accurately characterizing these fractured media is of paramount importance when it comes to tasks that demand precise predictions of liquid flow and solute transport within them. Since directly measuring fractured media poses inherent challenges, data assimilation (DA) techniques are typically employed to derive inverse estimates of media properties using observable state variables. Nonetheless, the considerable difficulties arising from the strong heterogeneity and non‐Gaussian nature of fractured media have diminished the effectiveness of existing DA methods. In this study, we formulate a novel DA approach known as parameter estimator with deep learning (PEDL) that harnesses the capabilities of DL to capture nonlinear relationships and extract non‐Gaussian features. To evaluate PEDL's performance, we conduct three case studies, comprising two numerical cases and one real‐world case. In these cases, we systematically compare PEDL with three widely used DA methods: ensemble smoother with multiple DA (ESMDA), iterative local updating ES (ILUES), and ES with DL‐based update (ESDL). Notably, in the problems characterized by highly non‐Gaussian features, ESMDA and ILUES produce significantly divergent results. Conversely, employing the DL‐based update, ESDL demonstrates improved performance. However, its estimation uncertainty remains high, potentially attributable to ESDL's updating mechanism. Comprehensive analyses confirm PEDL's validity and adaptability across various ensemble sizes and DL model architectures. Moreover, even in scenarios where structural difference exists between the accurate reference model and the simplified forecast model, PEDL adeptly identifies the primary characteristics of fracture networks. Key Points: A deep learning‐based data assimilation method, named parameter estimator with deep learning (PEDL), is proposed to characterize fractured media with highly non‐Gaussian featuresPEDL outperforms three popular data assimilation methods based on deep learning or the Kalman formulaComprehensive analyses confirm PEDL's validity and adaptability across various ensemble sizes and DL model architectures [ABSTRACT FROM AUTHOR]

The Archean Superior craton was formed by the assemblage of continental and oceanic terranes at ∼2.6 Ga. The craton is surrounded by multiple Proterozoic mobile belts, including the Paleoproterozoic Trans‐Hudson Orogen which brought together the Superior and Rae/Hearne cratons at ∼1.9–1.8 Ga. Despite numerous studies on Precambrian lithospheric formation and evolution, the deep thermochemical structure of the Superior craton and its surroundings remains poorly understood. Here we investigate the upper mantle beneath the region from the surface to 400 km depth by jointly inverting Rayleigh wave phase velocity dispersion data, elevation, geoid height and surface heat flow, using a probabilistic inversion to obtain a (pseudo‐)3D model of composition, density and temperature. The lithospheric structure is dominated by thick cratonic roots (>300 km) beneath the eastern and western arms of the Superior craton, with a chemically depleted signature (Mg# > 92.5), consistent with independent results from mantle xenoliths. Beneath the surrounding Proterozoic and Phanerozoic orogens, the Mid‐continent Rift and Hudson Strait, we observe a relatively thinner lithosphere and more fertile composition, indicating that these regions have undergone lithospheric modification and erosion. Our model supports the hypothesis that the core of the Superior craton is well‐preserved and has evaded lithospheric destruction and refertilization. We propose three factors playing a critical role in the craton's stability: (a) the presence of a mid‐lithospheric discontinuity, (b) the correct isopycnic conditions to sustain a strength contrast between the craton and the surrounding mantle, and (c) the presence of weaker mobile belts around the craton. Plain Language Summary: We introduce a new model of the temperature and composition of the Superior Craton, a stable and ancient (>2.5 billion years old) geological formation, and its neighboring areas, by using an advanced and novel imaging technique. The central aim of the study is to use the present‐day structure (from the surface to 400 km depth) to understand how the craton's lithosphere (the rigid outer layer of the Earth) has evolved over time, and how its deep roots have persisted over billions of years of geological processes. The Superior Craton displays well‐preserved cores with a distinct chemical composition beneath its eastern and western arms, which likely contribute to its long‐term preservation. Isopycnicity (a state of density equilibrium) within the lithosphere is a likely controller of long‐term stability. Additionally, the presence of layering in the lithosphere and weaker structures (e.g., mountain belts, rifts, hotspot tracks) surrounding the edges of the craton emerge as critical factors contributing to the resilience and endurance of the Superior Craton's lithosphere. These findings significantly advance our understanding of the mechanisms governing the evolution and stability of cratonic regions. Key Points: First integrated multi‐observable probabilistic thermochemical model of the lithosphere beneath the Superior craton and environsThe Superior craton shows well‐preserved depleted cores beneath its eastern and western armsLong‐term craton stability is likely controlled by isopycnicity, and the presence of mid‐lithospheric discontinuities and mobile belts [ABSTRACT FROM AUTHOR]

The storage of fluids in the subsurface is critical for a broad spectrum of applications including managed aquifer recharge, storage of liquefied carbon dioxide and hydrogen, geothermal heat extraction and exploitation of hydrocarbon. It is surprising then, that there has been relatively little measurement of the vertical distribution of poroelastic storage in geologic formations as compared with permeability. We present experiments in which fluid was injected into an important regional aquifer and the depth‐dependent strain response measured using fiber optic distributed acoustic sensing. The formation expansion and contraction in response to fluid injection were several 100 nanostrain. Strain, and the implied storage distribution, was highly localized in specific strata and demonstrated complex, hydromechanical behavior. This new window into fluid‐geomechanical coupling undermines some typically use models and observations currently in practice, but provides potential for complete representation and prediction of fluid storage in the subsurface. Plain Language Summary: A fiber optic cable was used to measure strain in response to water injection and withdrawal in a sandstone aquifer. The strain was found to be focused in limited strata within the aquifer. In some strata, the formation expanded with injection, and in others the formation contracted with injection. This complex behavior is attributed to the interaction between fluid flow and mechanical strain in the porous rock and is contrary to common models of water storage which predict a proportionate expansion of pore space with injection. These results provide important insight into understanding transient flow response to impulse and oscillatory pressure loading of the well. Key Points: Strain and flow direction was correlated or anti‐correlated with injection head, depending on injection intervalInjection and strain behavior was not simply correlated to geophysical or lithologic logsDynamic injection/withdrawal tests are of limited predictive value to managed aquifer recharge [ABSTRACT FROM AUTHOR]

Unconformity‐related uranium (URU) deposits in the Athabasca Basin, Canada, include the highest grade, large tonnage deposits in the world. Recent studies of the Patterson Lake corridor uranium deposits suggest a deep heat source enhances hydrothermal fluid flow and incursion of basinal brines along brittlely reactivated ductile shear zones. However, the spatial extent of the ore systems and lower crustal features capable of driving the hydrothermal cells remained largely unresolved. Three‐dimensional electrical conductivity models derived from inversion of magnetotelluric data and coincident gravity modeling identified a voluminous conductivity anomaly and corresponding gravity low related to a belt of high‐heat producing intrusions that dips below the deposit. Shallow conductive bodies are identified below the deposits and similarly prospective corridors. The volume and location of the intrusive bodies may have provided a source of radiogenic heat that helped drive remobilization of fluids along reactivated structures, redefining the spatial extent of URU systems. Plain Language Summary: The western Athabasca Basin, straddling the border of Saskatchewan and Alberta in Canada, is home to some of the highest‐grade, large tonnage uranium deposits in the world. Recent studies have suggested a spatial connection between uranium ore systems that are found near the earth's surface and geological processes occurring deep within the crust. However, the processes connecting the lower crust to these shallow deposits is poorly understood. This study used 3D models created from magnetotelluric data, a passive a geophysical technique that measures the earth's natural electric and magnetic fields, to image the earth from surface to a depth of 40 km. We identified a voluminous igneous intrusion that extends from the surface to great depths in the earth's crust. We propose that this intrusion may have contributed to the uranium endowment of the basin, and that radiogenic heat from the large igneous body helped circulate uranium‐bearing fluids through the shallow crust along reactivated geologic structures. The modeling, when combined with other geoscientific datasets, showcases the role of high‐heat producing granitic intrusions in driving the hydrothermal fluid cells that formed the deposits. Key Points: Integrated resistivity—gravity modeling over the Arrow uranium deposit in CanadaMagnetotelluric inversion images deep‐seated thermal source and fluid pathways that formed some of the highest‐grade uranium depositsHolistic ore system model illustrates relationship between crustal ore system and lower crustal resistivity anomalies [ABSTRACT FROM AUTHOR]

Estimating the longitudinal dispersion coefficient DL in flow through heterogeneous porous media is paramount to many problems in geological formations. Moreover, although it is well‐known that DL is sensitive to the morphology of such formations, it has been very difficult to establish a firm link between the two. We describe a novel deep convolutional neural network (DCNN) for estimating DL. The inputs for training of the network are a large and diverse set of data consisting of three‐dimensional images of porous media, as well as their porosity, and the associated DL values computed by random‐walk particle‐tracking (RWPT) simulations. The trained network predicts DL very rapidly, and its predictions are in excellent agreement with the data not used in the training. Thus, a combination of the DCNN and RWPT simulation provides a powerful tool for studying many flow‐related phenomena in geological formations, and estimating their properties. Plain Language Summary: Measuring or computing the dispersion coefficient DL in flow through porous media, a fundamental characteristic of transport in geological formations and risk analysis, is a time‐consuming endeaver. Moreover, although DL is sensitive to the morphology of a pore space, a direct link between the two has been missing. We proposed a deep convolutional neural network for predicting DL, using 3D images of porous media and their porosities. The accuracy of the predictions for the actual data indicates that the ability of the network for estimating the important flow and transport properties of porous media for new input data. The present work was at the core scale, on the order of the physical sizes of the sandstones used in our study. The same approach may be used at the eld scale. In that case, one generates the input data by following the same procedure, except that the data should be generated for models in which the permeability and porosity of the formation vary spatially, and represent correlated fields. Work in this direction is in progress. Key Points: Dispersion coefficientConvolutional neural networkFlow through porous media [ABSTRACT FROM AUTHOR]

The Palaeocene–Eocene boundary (PEB) interval has been recognized in the Patala Formation, Nammal Gorge Section, Pakistan using lithostratigraphy, stable carbon isotope stratigraphy and integrated biostratigraphy. Four distinct lithological units are identified in the Patala Formation in stratigraphic order from bottom to top; unit‐1 to unit‐4. The top of unit‐3 hosts three closely spaced unconformities demarcated as U1, U2, and U3. The PEB interval is represented by a negative shift of 1.61‰ in δ13CV‐PDB representing the carbon isotopic excursion (CIE) in unit‐2. Based on the encountered foraminifera, dinocysts, and calcareous nannoplanktons, the following biozones are identified across the PEB; two larger benthonic foraminiferal (LBF) zones (SBZ4 and SBZ5), the zonal boundary slightly postdating the CIE, two smaller benthonic foraminiferal zones (BB1 and BB2), three planktonic foraminiferal zones (P4/P5 + E1), four dinocysts zones (Pak‐DV, Pak‐DVI, Pak‐DVII, Pak‐DVIII), and two calcareous nannoplankton subzones (NP9a and NP9b). The following protist, dinocyst and calcareous nannoplanktons encountered in the studied interval advocates for the placement of the possible PEB at the level between samples NAM‐SH‐07 and 08; 1—presence of the smaller benthonic foraminifera Angulogavelinella avnimelechi diagnostic of the base of the CIE and the benthonic extinction event (BEE) Tethys wide, 2—presence of the cosmopolitan and the PEB diagnostic dinocyst species 'Axiodinium augustum', 3—presence of the PEB diagnostic Rhomboaster‐Discoaster calcareous nannoplankton assemblage. The LBF species Alveolina vredenburgi [a marker species of the Larger Foraminiferal Turnover (LFT) associated with the Palaeocene Eocene Thermal Maximum (PETM) and PEB in western Tethys] occurs slightly above the onset of the CIE. Previously reported compositional change in the LBF assemblage from the Salt Range [i.e. the replacement of the Palaeocene orbitoidiform LBF (Setia and Orbitosiphon) by the Eocene LBF (Orthophragminids, Alveolina, Nummulites and Assilina)] also postdates the PEB interval here. The late appearance of Alveolina vredenburgi and the compositional change in the LBF after the onset of the CIE are attributed to the facies variation across the PEB reflecting fluctuating depositional environment due to the active tectonic across this interval. This fluctuation is evident from the smaller benthonic and planktonic foraminiferal dominating assemblages in unit‐2 representing bathyal settings followed by LBF dominating unit‐3 representing shallow carbonate platform settings. The change in LBF assemblage closely resembles the well‐known LFT associated with the PETM as well as the carbonate platform stage III and the PEB reported from other Tethyan sections. [ABSTRACT FROM AUTHOR]

Geologic carbon storage is required for achieving negative CO2 emissions to deal with the climate crisis. The classical concept of CO2 storage consists in injecting CO2 in geological formations at depths greater than 800 m, where CO2 becomes a dense fluid, minimizing storage volume. Yet CO2 has a density lower than the resident brine and tends to float, challenging the widespread deployment of geologic carbon storage. Here, we propose for the first time to store CO2 in supercritical reservoirs to reduce the buoyancy‐driven leakage risk. Supercritical reservoirs are found at drilling‐reachable depth in volcanic areas, where high pressure (p > 21.8 MPa) and temperature (T > 374°C) imply CO2 is denser than water. We estimate that a CO2 storage capacity in the range of 50–500 Mt yr−1 could be achieved for every 100 injection wells. Carbon storage in supercritical reservoirs is an appealing alternative to the traditional approach. Plain Language Summary: Geologic carbon storage, which consists in returning carbon deep underground, should be part of the solution to effectively reach carbon neutrality by the middle of the century to mitigate climate change. CO2 has been traditionally proposed to be stored in sedimentary rock at depths below 800 m, where CO2 becomes a dense fluid, minimizing the required storage volume. Nevertheless, CO2 is lighter than brine in the traditional concept, so a rock with sufficient sealing capacity should be present above the storage formation to prevent leakage. Indeed, one of the main hurdles to deploy geologic carbon storage is the risk of CO2 leakage. To reduce this risk, we propose a novel storage concept that consists in injecting CO2 in reservoirs where the pore water stays in supercritical conditions (pressure and temperature higher than 21.8 MPa and 374°C, respectively) because at these conditions, CO2 becomes denser than water. Consequently, CO2 sinks, leading to a safe long‐term storage. This concept, which could store a significant portion of the total requirements to decarbonize the economy, should start being implemented in deep volcanic areas, given that supercritical reservoirs are found at relatively shallow depths between 3 and 5 km. Key Points: We propose a novel geologic carbon storage concept that reduces the buoyancy‐driven CO2 leakage riskBy injecting CO2 in reservoirs where the resident water stays in supercritical conditions, CO2 sinks because it is denser than pore waterSupercritical reservoirs are found at relatively shallow depths between 3 and 5 km in deep volcanic areas [ABSTRACT FROM AUTHOR]

The rate of carbon dioxide (CO2) dissolution in saline aquifers is the least well‐constrained of the secondary trapping mechanisms enhancing the long‐term security of geological carbon storage. CO2 injected into a heterogeneous saline reservoir will preferentially travel along high permeability layers increasing the CO2‐water interfacial area which increases dissolution rates. We provide a conservative, first‐principles analysis of the quantity of CO2 dissolved and the rate at which free‐phase CO2 propagates in layered reservoirs. At early times, advection dominates the propagation of CO2. This transitions to diffusion dominated propagation as the interfacial area increases and diffusive loss slows propagation. As surrounding water‐filled layers become CO2 saturated, propagation becomes advection dominated. For reservoirs with finely bedded strata, ∼10% of the injected CO2 can dissolve in a year. The maximum fraction of CO2 that dissolves is determined by the volumetric ratio of water in low permeability layers and CO2 in high permeability layers. Plain Language Summary: To limit global warming to 2°C, it is likely that large amounts of carbon dioxide (CO2) will need to be stored underground. A significant fraction of the total possible storage space for CO2 is in salt water reservoirs, kilometers beneath the surface. It is important that once the CO2 has been injected underground, it is securely trapped, otherwise, there is a risk that it could leak back to the surface. After the CO2 is injected into these reservoirs, it can dissolve in the surrounding water, greatly reducing the risk of leakage, although complete dissolution of all the injected CO2 may take millions of years. However, preferential flow of CO2 along more permeable layers in geological formations creates a complex front between the water and CO2 which increases the surface area available for dissolution. This study calculates the minimum amount of injected CO2 that can dissolve in such a reservoir and how far it travels. Using injection of CO2 for enhanced oil recovery at the Salt Creek Field in Wyoming as an example, we find that in one year around 10% of the total injected CO2 can dissolve into the surrounding water by this process and become trapped. Key Points: Injection of carbon dioxide into finely bedded reservoirs leads to enhanced contact area with water and hence enhanced dissolution ratesPropagation rates of free‐phase carbon dioxide transition from advection to diffusion dominated as the contact area with water increasesFor injection into the Salt Creek reservoir, Wyoming, nearly 10% of the injected carbon dioxide is predicted to dissolve in one year [ABSTRACT FROM AUTHOR]

The dynamic properties of freestanding rock landforms are a function of fundamental material and mechanical parameters, facilitating noninvasive vibration‐based structural assessment. Characterization of resonant frequencies, mode shapes, and damping ratios, however, can be challenging at culturally sensitive geologic features, such as rock arches, where physical access is limited. Using sparse ambient vibration measurements, we describe three resonant modes between 1 and 40 Hz for 17 natural arches in Utah spanning a range of lengths from 3–88 m. Modal polarization data are evaluated to combine field observations with 3‐D numerical models. We find outcrop‐scale elastic moduli vary from 0.8 to 8.0 GPa, correlated with diagenetic processes and identify low damping at all sites. Correlation of dense‐array measurements from one arch validates predictions of simple bending modes and fixed boundary conditions. Our results establish use of sparse ambient resonance measurements for structural assessment and monitoring of arches and similar freestanding geologic features worldwide. Plain Language Summary: Natural rock arches vibrate under ambient conditions with a unique set of frequencies controlled by geometry, host material, and interactions with nearby bedrock. Recent rockfall events at well‐known arches in Utah have highlighted the need to develop noninvasive assessment methods to better understand how these sensitive landforms evolve. To reduce site impacts, we employed limited instrumentation to measure ambient vibrations of 17 arches across Utah for identification of resonant frequencies. We combine direct observations with predictive numerical models to visualize resonant mode shapes and describe the controlling material properties and structural boundaries. In defining the first three modes of each site, we are able to characterize dynamic properties at arches encompassing several geologic formations and a range of length scales. These results establish a versatile method for structural evaluations of arches and other significant freestanding geologic features. Key Points: Single‐station ambient vibration data and numerical modeling describe the dynamic response of natural arches with limited site accessDense seismic array directly resolves resonant mode shapes, validating predictions of simple bending modes and fixed boundary conditionsSandstone arches in Utah resonate between 1 and 40 Hz, exhibit low damping, and have stiffness that vary with diagenetic conditions [ABSTRACT FROM AUTHOR]

Dynamic topography due to mantle flow contributes to shaping Earth's evolving landscapes by affecting sediment routing, which has rarely been explored in source‐to‐sink contexts. Here we design a generic model to investigate the impact of dynamic topography on both landscape evolution and stratigraphic formations. An imposed wave of dynamic topography propagates laterally under a fixed continent, exerting transient surface uplift and subsidence. We find that a migrating dynamic topography can induce significant drainage reorganizations and affect sediment routing from source to sink. Variations in sediment supply driven by the lateral migrating dynamic topography contribute to the formation of diachronous unconformities along the margin. The predicted sediment flux histories are then put into perspective with the Cretaceous sedimentary records along the Southern African margins. Finally, we demonstrate that correlating offshore depositional hiatuses and unconformities has the potential to constrain the spatiotemporal evolution of past dynamic topography events. Plain Language Summary: Convective motion within Earth's interior result in transient uplift and subsidence of the surface is called dynamic topography. This process slowly shapes landscapes over millions of years and identifying its fingerprints in the rock record remains a challenge. This study uses numerical modeling to investigate the erosional and depositional response of landscapes to sea level change and to mantle flow. We show that unlike sea level change, dynamic topography reorganizes river flows and changes sediment supply to offshore regions, generating various stratal patterns. We model a simple circular landscape that evolves similarly to the southern African landscape between 140 and 66 million years ago and suggest sedimentary fingerprints to link the evolution of the Earth's surface to the dynamics of its deep interior. Key Points: A propagating wave of dynamic topography can induce significant drainage reorganizations and affect sediment routing from source to sinkVariations in sediment supply driven by the migration of dynamic topography can create diachronous unconformities along continental marginsOur model predicts sediment flux histories comparable to that along the Southern African margins during Cretaceous times [ABSTRACT FROM AUTHOR]

Estimating flow and transport properties of porous media that undergo deformation as a result of applying an external pressure or stress is important to a wide variety of processes, ranging from shale formations into which a fracking liquid is injected to CO2 sequestration in geological formations. We propose a novel model for estimating the effective permeability of such porous media. Given the pore‐size distribution (PSD) of a porous medium before deformation, as well as the Young's modulus of its grains, the model uses Hertz‐Mindlin theory of contact between grains to compute the new PSD that results from applying an external pressure P to the medium and utilizes the updated PSD in the effective‐medium approximation to estimate the effective permeability at P. Comparison between the predictions and experimental data for several types of sandstones indicates excellent agreement between the two. Key Point: This demonstrates the first application of the effective‐media approximation to estimating the permeability of deforming porous media [ABSTRACT FROM AUTHOR]

Earthquakes caused by human activities have been observed for decades. Often these are related to industrial activities pumping fluids into deep geologic formations, like with wastewater disposal. The simplest theory connecting these processes to earthquakes is straightforward: injection leads to fluid pressure changes that either reduce the strength of preexisting faults or generate new faults. In practice, the conditions that lead to induced earthquakes are not always clear in ways that can be generalized. Kao et al. (2018, https://doi.org/10.1029/2018GL079288) show how the distribution of induced earthquakes in Western Canada relate to natural rates of deformation in the crust. Using these new results, they discuss an intriguing paradox: induced seismicity can cause short‐term increases in the seismic hazard that are followed by a period of reduced seismic hazard. Such hazard‐reducing scenarios are plausible but hinge upon simplifying assumptions about how the crust stores and releases strain energy in the form of earthquakes. Key Points: Geodetic data indicate a close relationship between crustal strain rates and induced earthquakesInduced earthquakes might reduce the seismic hazard in the long runHazard‐reducing scenarios hinge critically on a few major assumptions [ABSTRACT FROM AUTHOR]

This study focuses on the palaeoecology of the Late Devonian ostracods based on more than 4,500 carapaces and valves collected from stratal sections in western Junggar, NW China. According to the ostracod faunas from the Hongguleleng Formation, 3 ecological assemblages are proposed for open oceanic island arc context, that is, Ostracod Assemblage‐1, Ostracod Assemblage‐2, and Ostracod Assemblage‐3. They characterize the foreshore, nearshore, and offshore environments, respectively. The water energy should be the first environmental factor controlling the composition of the ostracod assemblages from the Lower Member of the Hongguleleng Formation, and salinity fluctuations could be also involved. [ABSTRACT FROM AUTHOR]

Penecontemporaneous dissolution has been considered as the dominant origin of reservoir formation, whereas epigenetic dissolution has also played certain roles in the improvement of reservoir capacity in the Upper Cretaceous Mishrif Formation in the Middle East. Here, we report a possible new reservoir origin based on a case study in the Halfaya oilfield of Iraq, that is, facies‐controlled eogenetic karstification. The most representative evidence is that early selective dissolution is not only present in relative high‐energy categories of rocks but also in low‐energy ones in the cored intervals. Meanwhile, the occurrence frequency of karstification varies among different environments and associated lithologies. In grainstones and packstones, spongy‐like dissolution pores and irregular karst channels are widely developed, with fillings and massive plastic breccias. In contrast, in wackestones, lots of high‐angle karst channels are developed based on biological burrows, and the karst is more frequently observed in the shoal environment than in the low‐energy environments. These characteristics are indication of eogenetic karstification. The model of this karstification can be attributed to a multiple superimposition of short‐term exposure during the penecontemporaneous stage and the medium‐term exposure after the shallow burial stage. The karst has impact on reservoir capacity, according to which 3 areas are divided in the increasing order, namely, the tight bedrock area, spongy‐like dissolution pores area, and karst channels and vugs‐filled area, among which the karst channels and vugs‐filled area is the most favourable for oil accumulation. This understanding might be general to the Mishrif reservoirs in the entire Middle East. [ABSTRACT FROM AUTHOR]

At the south‐western margin of the North China Craton (NCC), there existed a lot of Mesoproterozoic strata. However, it is hardly known about the Mesoproterozoic stratigraphic sequence and deep structures of the south‐western part of NCC (most is the Ordos Block) due to the thick Phanerozoic sedimentary cover above the Precambrian basement and strata. Combining the drilling well data, seismic profiles, and outcrops around the whole Ordos Block, it becomes possible to reveal the deep structure and distribution of Mesoproterozoic strata. The distribution and sedimentation of Mesoproterozoic at the southwestern margin of NCC were controlled by a series of NE–SW extension deep faults just existed in Mesoproterozoic Changcheng System and Jixian System. According to the drilling well data, the Changchang System includes several various thickness volcanic rocks, and the stratigraphic sequence and lithological combination are similar to the Yanliao Rift. During the sedimentation from Longjiayuan Formation to Duguan Formation, the water got deeper revealed by the content of Ce element gradually decreasing. However, the content of Ce element unusually increases during the steady subsidence of the Mesoproterozoic basin, while the Xunjiansi Formation sedimented. The deposition of tephra or hydrothermal might contribute a lot to the increase of the Ce element's content. Besides that, numerous soft‐sediment deformation structures developed in carbonate rocks of Mesoproterozoic Xunjiansi Formation at the south‐western margin of NCC. What's more, the Xunjiansi Formation with soft‐sediment deformation structures can be regarded as a marker bed for the comparison with the Wumishan Formation in Yanliao Rift. Besides that, there is a set of residual sandstone conformably covered the dolomite of Mesoproterozoic Fengjiawan Formation. It corresponds with Xiamaling Formation of Building System in Yanliao Rift System based on the stratigraphic sequence and relative sedimentary time limited by the youngest zircon U–Pb age peak 1,511.1 ± 10 Ma (n = 7) and single zircon U–Pb age 1,436 ± 28 Ma. Therefore, the south‐western part of NCC have high similarity of stratigraphic sequence and sedimentary framework with Yanliao Rift. Moreover, the development of volcanic rocks in Changcheng System, soft‐sediment deformation structures, and Ce abnormal increasing in Xunjiansi Formation might suggest that there developed an active Mesoproterozoic Rift in the south‐western part of the NCC similar to Yanliao Rift. Generally, the south‐western part of NCC share similar tectonic background with Yanliao Rift. [ABSTRACT FROM AUTHOR]

The Zhunmubutai ophiolitic mélange is a newly discovered ophiolite suite located between the Solonker‐Linxi ophiolite belt and the Erenhot‐Hegenshan‐Xi‐Ujimqin ophiolite belt, the central part of Xilinhot Microcontinent (XLMC). It was composed of plagiogranite, pyroxene peridotite, pillow basaltic andesite, and associated mafic rocks and surrounded by a quartz diorite pluton and mélange zone containing sandstones and slates of Early Permian Shoushangou Formation. In this study, zircon grains from a quartz diorite and a plagiogranite yield 206Pb/238U ages of 313 ± 1 Ma (MSWD = 1.60, n = 20) and 328 ± 1 Ma (MSWD = 0.9, n = 93), respectively. Sixty‐four zircons from the slate yielded ages ranging from 307 to 2,313 Ma, and with a peak at 340 Ma. These data indicate the Zhunmubutai ophiolitic mélange formed 300 to 340 Ma. The Zhunmubutai plagiogranites that have low contents of K2O (0.07–0.33 wt.%), K2O/Na2O (0.02–0.09), and Rb/Sr (0.01–0.05) show an oceanic plagiogranites affinity. They are also characterized by low contents of TiO2, Nd, Ta, and significant LREE enrichment. Furthermore, the εHf (328 Ma) values range from 14.23 to 18.87. These features suggest that the plagiogranite was originated by the anatexis of amphibolites and with crustal contamination. Combined with previous studies, suggest that the Zhunmubutai ophiolitic mélange may have formed in an extensional environment during the early stages of opening of an ocean basin. [ABSTRACT FROM AUTHOR]

This study presents 40Ar/39Ar ages of autochthonous glauconites from the lower segment of the onshore Karai Shale Formation of the Cauvery Basin that constrain its age from 100.3 ± 0.7 to 92.6 ± 0.6 Ma. The 40Ar/39Ar plateau ages of the 3 glauconite samples are consistent with the existing biostratigraphic age of Late Albian to Middle Turonian of the Karai Shale Formation. These ages are significant because of the occurrences of oceanic anoxic event (OAE)1d and oceanic anoxic event (OAE)2 in contemporaneous offshore deposits, the Sattapadi Shale and Bhuvanagiri Formation, respectively. Although in the onshore deposits, the glauconite ages mark condensed deposits of the transgressive Karai Shale. As onshore glauconitic deposits may be transitional to organic‐rich black shale deposits offshore in modern and ancient sedimentary settings, the 40Ar/39Ar ages precisely constrains the timing of Cretaceous oceanic anoxic events reported in the Cauvery Basin. [ABSTRACT FROM AUTHOR]

Large quantities of saddle dolomite, dolomite, calcite, celestite, fluorite, barite, quartz, and pyrite occur as fracture fillings in the fourth member of the Middle Triassic Leikoupo Formation in the Yuanba area, northeast Sichuan. They were found either as single mineral or mineral assemblages. The properties, origin, and evolution of the fluids from which these fracture fillings were precipitated were studied using a variety of methods, including polarized light microscopy, cathodoluminescence microscopy, fluid inclusions, and stable isotope analysis. Homogenization temperatures of the liquid–gas inclusions trapped within the dolomite ranged from 112 to 138 °C. Based on this temperature range and the oxygen isotope data, the δ18O values of the fluids from which the dolomite precipitated were determined to be between −5‰ and 7‰ (Standard Mean Ocean Water). The study suggests that the fracture‐filling dolomite, ubiquitous in the fourth member of the Middle Triassic Leikoupo Formation in the study area, was produced from high‐temperature, high‐salinity brines. These brines were interpreted to have originated from the mixtures of hot brines trapped in rock formations and hydrothermal fluids from deep sources and to have become enriched in strontium during diagenesis. [ABSTRACT FROM AUTHOR]

The present study integrates detrital zircon U–Pb–Hf isotopic analysis from 13 sandstone samples from an Upper Cretaceous–Miocene sedimentary sequence in Nepal Himalaya to determine their provenance. These sequences constrain a shifting of provenance from south to north. The U–Pb ages from Upper Cretaceous–Palaeocene strata (Amile Formation) mainly cluster between ~1,860 and 1,400 Ma with a peak at ~1,630 Ma and an absence of grains younger than the Palaeoproterozoic (1,400 Ma) age. The detritus yielded positive detrital zircon ƐHf (t) values (as high as +10). However, the detrital zircon U–Pb ages from Eocene–Miocene sequence cluster at ~500–650, ~700–900, ~1,600–1,850, and ~2,500 Ma, and in addition, they have both positive and negative ƐHf (t) values (+11 to −25). This finding further elucidates that the detritus in the Amile Formation was entirely sourced from India, which changed following the time of the Bhainskati Formation deposition, to a mixture of both Asian and Indian affinities (the Himalayan region). This change in source region marks the possible time of the India–Asia collision during this transition phase, that is, Late Palaeocene–Earliest Eocene. [ABSTRACT FROM AUTHOR]

The middle Eocene Fulra Limestone Formation of the Kachchh Basin, western India was investigated to interpret depositional environments and sources of limestones based on facies analysis, mineralogy, and major, trace, and rare earth elements (REEs) geochemistry. Facies stacking pattern of the Fulra Limestone Formation exhibits an overall shallowing‐upward sedimentary succession developed in the middle to inner ramp to lagoonal set‐up. Staining of the thin sections and X‐ray diffraction patterns show dominance of calcite mineral. The CaO, ranging from 40.45% to 49.69%, is the dominant oxide among the major oxides followed by SiO2 (4.04–10.3%). The dominance of CaO over MgO suggests that the major mineral phase has been calcite and no dolomitization occurred during the deposition of the Fulra limestone. The low proportion of SiO2 and Al2O3 suggests low siliciclastic input during the precipitation of the Fulra limestone that is confirmed by the positive correlation of ∑REE with Al2O3, Fe2O3, Ni, Th, Sc, and Y and the negative correlation of SiO2, Al2O3, and Sr with CaO. The average value of REE contents in the Fulra Limestone Formation are lower (*16.02 ppm) than the average value of typical marine carbonates (*28 ppm). The Post‐Archean Australian Shale‐normalized REE + Y patterns of the Fulra limestone exhibit seawater like shale‐normalized REE + Y pattern, whereas slightly lower average value of Y/Ho ratio (34.60) than the typical seawater value (~44–74) suggests modification of the seawater, to some extent, by input of freshwater in a coastal environment. The REEs of the Fulra Limestone Formation have similarity with the carbonates of the Arabian Sea and/or shallow marine carbonates with exception of a few elements. It is envisaged from this study that the Fulra limestone was deposited in a shallow marine to coastal set‐up where mixing of the continental material in seawater was feasible. [ABSTRACT FROM AUTHOR]

Permo–Triassic (P–T) successions in Iran are known as one of the most extensive carbonate–evaporite sequences in the world, holding prolific hydrocarbon accumulations, such as the gas fields in the Zagros Basin. This study addresses the impact of paleoenvironmental changes across the P–T extinction boundary, variations in eustatic level and diagenesis on the carbonate reservoir quality of the Permo–Triassic Upper Dalan and Kangan formations in the Lavan Gas Field (offshore Zagros). A total of eight lithofacies have been defined and interpreted, representing the shallower parts (inner ramp to shoal) of a carbonate homoclinal ramp. The diagenetic features show the mixing influence of marine, meteoric and burial processes, with prevalence of multistage dolomitization and late meteoric‐related imprints. The main dolomitization processes are interpreted to be penecontemporaneous and associated with continuous seawater reflux and high evaporation within the intertidal environment. Combined analysis of facies and petrophysical properties has been utilized to define six rock types, including RT4 (grainstones from oolitic shoals) as the best reservoir, whereas RT1 (supratidal anhydrite) is acting as the main cap rock within the studied carbonate–evaporite sequence. Multiscale characterization of lithological and petrophysical properties suggest that the Upper Dalan Formation has a single reservoir unit (D1), whereas the Kangan Formation may be divided into two reservoir units (K1 and K2). The best reservoir quality is promoted by dissolution and dolomitization associated with late Transgressive Sequence Tracts (TST) to early Highstand Sequence Tracts (HST) sequences, while low reservoir quality corresponds to late HST sequences accompanied by pore‐occluded cements. Petrophysical analysis suggest better porosity‐permability for the Upper Dalan than for the Kangan Formation. This observation is closely associated with the different nature of lithofacies, where the Kangan Formation contains more fine‐grained carbonate rocks, and the higher intensity of porosity‐grain dolomitization in the Upper Dalan Formation. This study provides a better understanding on reservoir quality prediction across the P–T boundary and the effect of eustatic fluctuations and diagenesis in controlling porosity‐permeability evolution with similar settings elsewhere. [ABSTRACT FROM AUTHOR]

Our study on the seamounts in the southeast Caroline Plate reveals a formation of a special kind of seamounts in the oceanic basin. These moniliform seamounts link up like the reason of hotspots, but the tectonic factors lead to their formation. The differential motions of the Caroline, North Bismarck, and Pacific plates resulted in the shear stress field by the West Melanesian Trench. The R and R′ faults can be distinguished obviously by seafloor topography. The evolution history of these seamounts can be subdivided into two stages as follows. (a) The R′ faults developed firstly as normal faults to generate ridges on these faults as the release of the underlying sediments. (b) The R faults appeared as shear faults and cut off the ridge from the older R′ faults. These faults can be very deep fractures, which cut through the lithosphere and produced a NW‐trending negative anomaly in isostatic gravity anomaly. As the pressure is released by the R faults, the sediments releasing under the R faults accumulated into these seamounts. The other sections of the R faults performed like a valley because of the leakage of sediments along the faults. Sediments would also release along the R faults to generate ridges when no seamount occurs on the faults. [ABSTRACT FROM AUTHOR]

A significant proportion of shale gas resources occurs in Lower Silurian Longmaxi Formation in southeast Sichuan Basin, South China, where commercial gas production has been achieved at Fuling Shale Gas Field. This study area is located adjacent to Fuling Jiaoshiba shale play. Elemental geochemistry regarding paleoenvironment aspects of lower Silurian Longmaxi shale gas is poorly understood. However, the samples in this study are representative, revealing the complete elemental geochemical characteristics of Longmaxi Shale. This research has analysed trace and rare earth elements of lower Silurian Longmaxi Shale and investigated the depositional environment, provenance, and tectonic settings when this type of shale formed. Sedimentary structures include horizontal lamination, massive lamination, and deformation structures that are well developed in black shale and grey silty shale of lower Silurian Longmaxi Formation. Gamma ray, total organic carbon, and pyrite contents are relatively higher in the lower part of the shale. The enrichment of sulfophile heavy metal elements (Cu, Zn, Pb, Mo, Ni) indicates that a reducing environment is common during the deposition of Longmaxi Formation. The concentration of rare earth elements is generally constant with relatively high concentration of light rare earth elements, stable concentration of heavy rare earth elements, and negative Eu anomalies. The sediments of Longmaxi Formation are derived primarily from the sedimentary rocks and granites in continental crust. The combination of trace and rare earth elements indicates that the tectonic settings of the provenance are continental island arc and active continental margin. [ABSTRACT FROM AUTHOR]

The North Qilian orogenic belt is the key in the exploration of the formation and assembly of Asia. The Early–Middle Devonian Xueshan Formation, which is deposited in the north area of North Qilian Orogenic Belt, is the most important for revealing the evolution basin–mountain transition of the North Qilian Belt. In order to reveal the tectonic evolution of the central orogenic belt in China and Paleozoic global plate reconstruction, it is necessary to perform provenance analysis of the Xueshan Formation. Eighteen samples were collected from Yumen and Yongchang profiles in the west of North Qilian Belt (WN), and 16 samples were obtained from Gulang and Jingtai profiles in the east of North Qilian Belt (EN). The compositions of clastic conglomerates and the sandstones suggested that felsic volcanic was the main source of the WN Xueshan Formation deposits and that the sedimentary and metamorphic rocks were the main source of the EN sediments. According to major geochemistry indexes, such as Al2O3/SiO2 ratio ranging from 0.08 to 0.37 and the chemical index of alteration less than 80, the source rocks were moderately weathered and of moderately matured. The samples from the EN were relatively enriched in Cr, Ni, Sc, and V elements and depleted in Hf element. However, those from the WN were enriched in Hf without the enrichment of Cr, Ni, Sc, or V. The samples from WN showed a strong negative Eu anomaly, but the samples from EN showed a weak negative Eu anomaly or a positive Eu anomaly. All the above geochemical characteristics suggested the prominent input of felsic clasts with granitic rocks into the WN. Meanwhile, the discrimination diagrams of trace elements implied that WN rocks were derived from continental island arc and that the EN rocks were derived from orogenic belt and the passive continental margin. The North China Plate subducted southwards and formed subduction‐related arc magmatism along the southern margin of the North Qilian Terrane during the Early–Middle Devonian. In conclusion, the WN is a fore‐arc basin, but EN is a foreland basin. [ABSTRACT FROM AUTHOR]

During the Early Carboniferous, the northeastern Qaidam Basin probably formed in an active continental margin setting. Due to marine regression after the late Early Carboniferous, the marginal shelf began to receive more terrestrial clastic sediments, and alternating occurrence of carbonates and siliciclastics characterized this region. Consequently, shales or mudstones with considerable thickness were deposited in the Upper Carboniferous, especially in the Keluke Formation. In order to illuminate a more accurate sedimentary environment of shales and further evaluate the shale gas potential, multidisciplinary traditional methods were conducted including rock core examinations and laboratory analysis. Results reveal that the sedimentary microfacies of shales in the Keluke Formation can be divided into the upper shoreface, the lower shoreface, and the upper to transition offshore. These microfacies developed on a homoclinal carbonate ramp with a gentle slope. The thickest succession of mudstone develops in the lower shoreface, which is a counterpart with the lagoonal setting of a stationary hydraulic system. The quartz content of shale samples ranges from 30% to 66% and clay minerals from 24% to 43% by bulk compositional analysis, which indicates the content of brittle minerals and shales fissility to some extent. The total organic carbon content ranges from 0.5% to 7.6% by weight, with an average value of 2.69% in ZK1‐1 and 1.11% in ZK3‐2, indicating abundant organic matter richness. The kerogen is mainly of type II, which indicates that source for the organic matter is a mixture of higher terrestrial plants and acquatic organisms. The vitrinite reflectance ranges from 1.22% to 1.55%, indicating a moderate to high thermal maturity. Three types of pores are recognized in the shales, including organic pores, intrapartical pores, and interparticle pores. The significance of this work emphasizes two aspects. First, it gives a more detailed classification of sedimentary environment of the mudstone succession; second, it acquires the preliminary subsurface data regarding to the shale gas potential evaluation. [ABSTRACT FROM AUTHOR]

The correlation between dike density and regional‐scale mineralization indicates a fundamental criterion for ore‐forming process. Here, a novel dike distribution density method is formulated for evaluating this correlation and exploring mine targets quantitatively. Three parameters (dike density, dike orientation scatter degree and dike fractal dimension) are proposed to express the degree of irregularity and complexity of dike distribution patterns. This method is applied to the South Alatao Mountains area (China), where the dike swarms show regionally well‐developed density gradients and the mineral deposits are spatially associated with abundant dike swarms. On the basis of this quantitative dike distribution density method, 60% of the deposit targets are delineated in this area. This result indicates that the method is an effective quantification tool for prospecting mine targets. The dike distribution density method is applicable for areas where abundant regional‐scale dike swarms and mineralization occur. It should be considered as an effective and complimentary technique for the common mine prospectivity analysis. [ABSTRACT FROM AUTHOR]

Abstract: Determining the ages of young planetary surfaces relies on using populations of small, often sub‐km diameter impact craters due to the higher frequency at which they form. Smaller craters however can be less reliable for estimating ages as their size‐frequency distribution is more susceptible to alteration with debate as to whether they should be used at all. With the current plethora of meter‐scale resolution images acquired of the lunar and Martian surfaces, small craters have been widely used to derive model ages to establish the temporal relation of recent geologic events. In this review paper, we discuss the many factors that make smaller craters particularly challenging to use and should be taken into consideration when crater counts are confined to small crater diameters. Establishing confidence in a model age ultimately requires an understanding of the geologic context of the surface being dated as reliability can vary considerably and limitations of the dating technique should be considered in applying ages to any geologic interpretation. [ABSTRACT FROM AUTHOR]

The restrictive factors of cultivated land are key to the improvement of cultivated land quality, scientific implementation of the land consolidation projects, and the efficiency of remediation. On the basis of the provincial plots of cultivated land quality in Shaanxi Province, this paper analysed the improvement potential of cultivated land quality from the perspective of restrictive factors. First, the potential exponential model was used to determine the distribution of various combinations of restrictive factors at the provincial scale. Second, a geological detector was used to determine the influences of different combinations of restrictive factors on cultivated land quality. Finally, through the investigation of cultivated land consolidation projects that have been implemented in the study area, the improvement potential level of different combinations of restrictive factors was determined. The degree of influence of the single restrictive factor or combinations of restrictive factors on the quality of cultivated land was improved, and the difference of the quality of cultivated land in different index areas could be revealed as well. The results showed that there were 12 single‐factor restrictions and 34 double‐factor restrictions. The area under single‐factor restrictions reached 76.77% of the total land. The quality of cultivated land in the southern and central areas of Shaanxi Province was relatively good. The quality of cultivated land in the northern region was under significant influence of restrictive factors whereas that in southern and middle areas was less affected. From the perspective of improvement potential of restrictive factors, Shaanxi was relatively low with huge internal diversity, whereas the improvement potential in northern Shaanxi had huge advantage. [ABSTRACT FROM AUTHOR]

To study the status quo of research on geological hazards in the Central China Orogen and its geological distribution quantitatively, we used bibliometric methods and deeply analysed the numbers, the authors and research institutions involved, and the distribution and changes of the research contents of papers on geological hazards published from 1962 to 2016. This review involved 26,677 documents, 26,339 authors, and 11,095 research institutions. The results showed that the study of geological hazards has significant time‐domain characteristics. In this field, the greatest number of papers was published in Recent Developments in World Seismology and the Chinese Journal of Geophysics–Chinese Edition, with 456 and 159 papers, respectively. As shown by an analysis of keywords, the current research focuses mainly on the evaluation, distribution characteristics, development regularity, detection and prediction, and prevention and control of geological hazards. The conclusions find that the authors of foreign‐published papers are mostly Chinese researchers, which cannot reflect the status quo of foreign research in this field to a certain extent. Differentiation between domestic and foreign research approaches and objectives through comparative analysis should be further explored. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin (ECSSB) lies at the south‐eastern margin of the Eurasian Plate and was affected by the subduction of the Pacific Plate and the Philippine Plate. It experienced and recorded multistage tectonic inversions in the Cenozoic, especially in the Xihu Sag. In an attempt to investigate the evolution and mechanism of tectonic inversion, this paper presents numerical simulation results by the finite element method to the Xihu Sag. Combined with comprehensive structural analyses of seismic profiles, this paper determines the structural geometry of the sag for establishing a viscoelastic geologic model including six‐layer strata and nine major faults. Simulation results show that the boundary conditions of transtension and transpression control the inversion process that propagates from east to west, and the distribution of low compressive stress displays certain correlations with the distribution of oil deposits. Based on quantitative analysis of the vertical displacement field of the Xihu Sag, this paper identifies a tectonic inversion process, which indicates that the western part of the sag uplifts and the eastern part subsides during the first‐stage inversion; whereas the western part subsides and central‐eastern parts uplift during the second and third stages. The formation of the tectonic inversion is controlled by the adjustment of the stress field from dextral transtension to sinistral transpression caused by the change of subduction rates and direction of the Pacific Plate and the Philippine Sea Plate. [ABSTRACT FROM AUTHOR]

The sedimentary features of the Cixerri Formation (Eocene–Oligocene) and its evolution in space and time are described through mapping, investigation of all the significant outcrops, and also by analysing the depositional architecture of well‐exposed and laterally extensive outcrops. The Cixerri Formation marks the middle Eocene Pyrenean unconformity and blankets a former structural ridge‐and‐swale morphology. This started by covering the flanks of the ridges with small alluvial fans and ultimately filled the swales with fluvial deposits in braided to meandering stream environments. In this latter sedimentation phase, the depositional environment of the formation evolved both upwards, and from west to east, to gradually lower energy environments, suggesting a transgressive‐type evolution. The Eocene–Oligocene Cixerri Formation was deposited by a fluvial network with a regular flow regime under a humid–warm climate: This network was formed by a main W‐E‐directed trunk and a NW‐SE‐directed minor branch that ultimately joined together. The Cixerri Formation, which was fed by the erosion of a sector of the Pyrenean Chain, passes upwards to coarser deposits that indicate the transition from a quiet tectonic environment to an active transtensional tectonic phase (Apennine phase). A comparison with similar coeval formations in Northern Sardinia, Corsica, and the Western Mediterranean area (Balearic Islands, France) is attempted, before the significance of the formation in the Pyrenean orogeny is then discussed. [ABSTRACT FROM AUTHOR]

The East China Sea Shelf Basin (ECSSB) is an important tectonic unit of the western Pacific active continental margin. It is divided further into a series of sags and basement ridges. The Xihu Sag on the east margin of the ECSSB is an important hydrocarbon exploration area and contains significant petroleum resources. The Huagang Formation is the major reservoir in Xihu Sag, and its provenance has been the focus of debate at all times. The major and trace elements (including rare earth elements) compositions were analyzed for the Oligocene Huagang Formation sandstone and mudstone samples in the Xihu Sag. The provenance and tectonic setting of these clastic rocks are discussed. The Chemical Index of Alteration value and A–CN–K diagrams suggest low to moderate weathering in the source areas of the Huagang Formation. The mudstones have lower index of compositional variation values (<1), indicating that the mudstone samples are compositionally mature, whereas the index of compositional variation values for the sandstone samples (0.59 to 1.87) indicate that the sandstones are compositionally immature and mature. The major and trace element composition and ratios of the clastic rock samples indicate that mudstones are mainly from Late Mesozoic igneous rocks in SE China, which is dominated by the acidic volcanic rock. The provenance of sandstones is from two different directions, the Central Uplift Group of ECSSB and the Taiwan–Sinzi Fold Belt with more mafic volcanic rock. Based on the geochemical analysis of the clastic rock samples, the tectonic setting of Xihu Sag was Japanese‐type continental margin during the Huagang Formation deposition time (Oligocene). [ABSTRACT FROM AUTHOR]

The Chagan Sag is a small Early Cretaceous intracontinental passive rift subbasin in the Yingen‐Ejinaqi Basin Group generated on the Tianshan‐Xingmeng Orogenic Belt. The Lower Cretaceous strata contain the Bayingebi, Suhongtu, and Yingen formations deposited during the syn‐rift phase. The Wuliji Structural Zone bounded by a high‐dip syn‐sedimentary fault is an intensively studied area with an extent of ~300 km2 having abundant available subsurface dataset and great hydrocarbon potential. According to well‐ and seismic‐based sequence stratigraphic study, the Upper Bayingebi Member generally corresponds to a complete third‐order transgressive–regressive sequence in the Wuliji Structural Zone. The transgressive system tract gradually thins towards the north, but the regressive system tract covers the entire study area in this third‐order sequence. Further investigations reveal that tectonic subsidence and climate change are two predominant allogenic factors for controlling stratigraphic development in the Wuliji Structural Zone. During the deposition of the Upper Bayingebi Member, transverse gravity flow dominated fan‐delta complexes sourced from the Maodun Subuplift are well developed in the Wuliji Structural Zone. The retrogradational conical fan deltas are mainly located in the southern sector during the transgressive system tract stage, but the progradational Gilbert‐type fan deltas are widely developed during the regressive system tract stage. The sedimentary evolution and stratigraphic architecture are directly linked with preexisting topography, accommodation, and sediment supply. In addition, climate change and vegetation types are thought to be critical controls for fluid properties originated from feeder drainage systems and depositional processes of the construction of fan‐delta complexes in the distinct system tracts. [ABSTRACT FROM AUTHOR]

The late Jurassic Qal'eh Dokhtar Formation lithologically comprises three parts, from bottom to top, a lower sandstone unit, middle shale unit and an upper carbonate unit, which extend in a N–S direction over a wide area to the east of the Shotori Range and west of the Lut Block (Central Iran). This succession was deposited on a mixed carbonate–siliciclastic ramp. Carbonate rocks of the Qal'eh Dokhtar Formation vary from undolomitized, to partly dolomitized, to completely dolomitized. Field observations from two measured sections (the type section, 955 m thick, and the Sorond section, 639 m thick), combined with detailed petrographic and geochemical analyses, revealed the diverse types of dolomite in this formation. Five types of replacement dolomite and one type of dolomite cement were distinguished. Replacement dolomites (RD) consist of: (1) fine crystalline planar‐s (RD1); (2) medium crystalline planar‐s (RD2); (3) medium crystalline planar‐e (RD3); (4) coarse crystalline planar‐s (RD4); and (5) coarse crystalline planar‐e (RD5). Coarse crystalline planar dolomite cements (DC) were observed in low abundance and filling dissolution voids and fractures. Variation in dolomite types is mainly related to early to late diagenetic processes leading to changes in composition of the dolomitizing fluids. Replacement dolomites are non‐stoichiometric (Ca43‐56–Mg34‐45) with Sr, Mn and Fe concentrations of 41–138 ppm, 168–919 ppm and 5000–21000 ppm, respectively. These dolomites are characterized by δ18O values ranging from 0.0 to –11.8 ‰ VPDB and δ13C values of +1.1 to +3.2 ‰ VPDB. These values are depleted in δ18O relative to the postulated values for late Jurassic dolomites precipitated in equilibrium with seawater, while δ13C values are within the range of Jurassic seawater dolomite values. Fluid inclusion data of RD4, RD5 and DC yield homogenization temperatures of 72 to 118 °C. Based on petrographic, fluid inclusion microthermometric data and geochemical results, the replacement dolomites in the Qal'eh Dokhtar Formation are interpreted to have formed in the subsurface at shallow to intermediate burial depths. These dolomites were then recrystallized at increased burial depths and temperatures. Seawater was the major source of Mg2+ for early diagenetic dolomite (DR1), while Mg2+ for late diagenetic dolomites was provided from diagenesis of clay minerals in shales and mechanical compaction of mudstone in the Qal'eh Dokhtar Formation. The dolomite cement is postdated by coarsely crystalline mosaic calcite cement indicating that diagenetic fluids eventually became undersaturated with respect to dolomite and oversaturated with respect to calcite. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Charcoal morphometry is increasingly employed in the analysis of Quaternary sediments, but has not been applied in studies of earlier sediments. We present findings relating to charcoal morphometry and morphotypes in a Toarcian sequence, which contains a preponderance of highly elongate forms, and morphometric values well outside expected ranges. SEM imaging reveals elongate particles of two distinct kinds. One originates in conifer xylem, and may be associated with formation at high levels of heating. It is proposed that the other may derive from tree ferns, or from plants with similar growth forms. Our results show the importance of recognizing the wide morphological variation that exists in sedimentary charcoal. Failing to do so may result in serious errors in its identification, interpretation and quantification. [ABSTRACT FROM AUTHOR]

With the recent discovery of new oil fields around the Dongying Depression, Bohai Bay Basin, a better understanding of the origin of its high-quality lacustrine carbonate reservoirs has become important. The lacustrine carbonates of the upper fourth member of the Eocene Shahejie Formation (ES4s) have been examined using a variety of methods, including core and thin section observations, XRD, SEM, CL and fluid inclusion and isotope testing. The δ13C and δ18O values of the Dongying carbonates differ significantly from Eocene marine values, and the 87Sr/86Sr ratios of carbonate minerals are higher than Eocene marine water and the same as the surrounding Palaeozoic carbonate bedrock. Additionally, the distribution of the carbonates is controlled by the surrounding Palaeozoic carbonate bedrock, all of which indicate their lacustrine origin. Six major carbonate lithofacies are distinguished in the southern gentle slope zone. Bioclastic, oolitic and intraclastic grainstones dominate the littoral to sublittoral zones, while mudstones are mainly distributed in the profundal zone. The ES4s interval is composed of a third-order depositional sequence that contains several small-scale, higher frequency depositional cycles. Overall, stacking patterns of high-frequency depositional cycles are consistent with the general facies variation from basin to shore. Shallow-water grainstones contain both primary intergranular and secondary dissolution pores, whereas the dolomitized mudstones in the profundal zone contain intercrystalline pores and fractures. Diagenetic processes that improve reservoir quality include dissolution and dolomitization. Reservoir quality was diminished by burial calcite cementation and compaction. High-quality reservoirs are mostly distributed in dolomitized grainstones and wackestones, which are deposited in the shoal facies of shallow lakes. Variations in reservoir quality in the Dongying Depression are due to a combination of lithofacies type, dissolution intensity, early dolomitization and tectonic-related deformation. Due to the influx of meteoric waters and shallow burial depth, the grainstones in the littoral zone have the best reservoir quality. Integrated studies have helped to understand the reservoir heterogeneity and hydrocarbon potential of the Dongying lacustrine carbonates. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

New information has been obtained in recent years regarding formation rates and the production size-frequency distribution ( PSFD) of decameter-scale primary Martian craters formed during recent orbiter missions. Here we compare the PSFD of the currently forming small primaries (P) with new data on the PSFD of the total small crater population that includes primaries and field secondaries (P + fS), which represents an average over longer time periods. The two data sets, if used in a combined manner, have extraordinary potential for clarifying not only the evolutionary history and resurfacing episodes of small Martian geological formations (as small as one or few km2) but also possible episodes of recent climatic change. In response to recent discussions of statistical methodologies, we point out that crater counts do not produce idealized statistics, and that inherent uncertainties limit improvements that can be made by more sophisticated statistical analyses. We propose three mutually supportive procedures for interpreting crater counts of small craters in this context. Applications of these procedures support suggestions that topographic features in upper meters of mid-latitude ice-rich areas date only from the last few periods of extreme Martian obliquity, and associated predicted climate excursions. [ABSTRACT FROM AUTHOR]

Exceptionally preserved 'Burgess Shale-type' fossil assemblages from the Cambrian of Laurentia, South China and Australia record a diverse array of non-biomineralizing organisms. During this time, the palaeocontinent Baltica was geographically isolated from these regions, and is conspicuously lacking in terms of comparable accessible early Cambrian Lagerstätten. Here we report a diverse assemblage of small carbonaceous fossils ( SCFs) from the early Cambrian (Stage 4) File Haidar Formation of southeast Sweden and surrounding areas of the Baltoscandian Basin, including exceptionally preserved remains of Burgess Shale-type metazoans and other organisms. Recovered SCFs include taxonomically resolvable ecdysozoan elements (priapulid and palaeoscolecid worms), lophotrochozoan elements (annelid chaetae and wiwaxiid sclerites), as well as 'protoconodonts', denticulate feeding structures, and a background of filamentous and spheroidal microbes. The annelids, wiwaxiids and priapulids are the first recorded from the Cambrian of Baltica. The File Haidar SCF assemblage is broadly comparable to those recovered from Cambrian basins in Laurentia and South China, though differences at lower taxonomic levels point to possible environmental or palaeogeographical controls on taxon ranges. These data reveal a fundamentally expanded picture of early Cambrian diversity on Baltica, and provide key insights into high-latitude Cambrian faunas and patterns of SCF preservation. We establish three new taxa based on large populations of distinctive SCFs: Baltiscalida njorda gen. et sp. nov. (a priapulid), Baltichaeta jormunganda gen. et sp. nov. (an annelid) and Baltinema rana gen. et sp. nov. (a filamentous problematicum). [ABSTRACT FROM AUTHOR]

The first fossil echinoids are recorded from the Cayman Islands. A regular echinoid, Arbacia? sp., the spatangoids Brissus sp. cf. B. oblongus Wright and Schizaster sp. cf. S. americanus (Clark), and the clypeasteroid Clypeaster sp. are from the Middle Miocene Cayman Formation. Test fragments of the mellitid clypeasteroid, Leodia sexiesperforata (Leske), are from the Late Pleistocene Ironshore Formation. Miocene echinoids are preserved as (mainly internal) moulds; hence, all species are left in open nomenclature because of uncertainties regarding test architecture. All Miocene taxa are recorded from single specimens apart from the 27 assigned to Brissus. Schizaster sp. cf. S. americanus (Clark) is compared to a species from the Oligocene of the south-east USA. Brissus sp. cf. B. oblongus is close in gross morphology to a taxon from the Miocene of Malta. Leodia sexiesperforata is identified from fragments with confidence, being the only extant Antillean sand dollar with elongate ambulacral petals that is limited to carbonate substrates. The Miocene echinoids of Grand Cayman, although of limited diversity, are mainly comprised of genera common in comparable mid-Cenozoic carbonate environments. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Combined with the actual geological settings, tight oil is the oil that occurs in shale or tight reservoirs, which has permeability less than 1 mD and is interbedded with or close to shale, including tight dolomitic oil and shale oil. The Fengcheng area (FA), at the northwest margin of the Junggar Basin, northwest China, has made significant progress in the tight oil exploration of the Fengcheng (P1f) Formation recently, which indicates that the tight oil resources have good exploration prospects. Whereas the lack of recognition of hydrocarbon generation and expulsion characteristics of Permian P1f source rocks results in the misunderstanding of tight oil resource potential. Based on the comprehensive analysis of geological and geochemical characteristics of wells, seismic inversion, sedimentary facies, tectonic burial depth, etc., the characteristics of P1f source rocks were investigated, and the horizontal distributions of the following aspects were predicted: the thickness of source rocks, abundance and type of organic matter. And on this basis, an improved hydrocarbon generation potential methodology together with basin simulation techniques was applied to unravel the petroleum generation and expulsion characteristics of P1f source rocks in FA. Results show that the P1f source rocks distribute widely (up to 2039 km2), are thick (up to 260 m), have high total organic content (TOC, ranging from 0.15 to 4 wt%), are dominated by type II kerogen and have entered into low mature-mature stage. The modeling results indicate that the source rocks reached hydrocarbon generation threshold and hydrocarbon expulsion threshold at 0.5% Ro and 0.85% Ro and the comprehensive hydrocarbon expulsion efficiency was about 46%. The amount of generation and expulsion from the P1f source rocks was 31.85 × 108 and 15.31 × 108 t, respectively, with a residual amount of 16.54 × 108 t within the source rocks. Volumetrically, the geological resource of shale oil is up to 15.65 × 108 t. Small differences between the amounts calculated by the volumetric method compared with that by hydrocarbon generation potential methodology may be due to other oil accumulations present within interbedded sands associated with the oil shales. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In Eastern Sardinia during the early Middle Jurassic, Alpine Tethys opening triggered the rise of a temporary tectonic high. The high collapsed rapidly, was fragmented into separate blocks, and subsequently covered by continental, transitional, and finally shallow marine deposits forming a narrow depositional system comprising the Genna Selole Fm. Present-day exposures in the southern part of the palaeo-high allow the sedimentological evolution of the transgressive cover sequence to be ascertained. Initial terrestrial deposits comprise alluvial fan deposits located at the mouths of palaeovalleys. These pass into braid-deltas and in the coastal areas located between adjacent valleys mouths, palustrine and coastal plain tidally-influenced environments developed. These environments interfingered laterally and passed seaward into a transitional, siliciclastic to carbonate tidal environment. With the collapse of the tectonic high, the continental to transitional environments were transgressed with deposition of marine carbonates. A comparison with similar coeval deposits of the W-Mediterranean domain has been undertaken. [ABSTRACT FROM AUTHOR]

This work presents fission-track ages and thermal history modelling of apatite samples from two Brazilian alkaline formations: Alto Paranaíba and Ponta Grossa Arches. The apatite fission-track ages obtained for Alto Paranaíba Arch agree with those determined by other radiometric dating methods presenting higher closure temperatures. The ages given by the fission-track thermochronometer suggest that no strong tectonic event has occurred after Alto Paranaíba Formation during Upper Cretaceous. This event is also supported by thermal history modelling of this arch, which is characterized by fast cooling followed by residence at lower temperatures. On the other hand, apatite fission-track ages from Ponta Grossa Arch are systematically lower than other radiometric ages, suggesting that at least one tectonic event occurred after Ponta Grossa Formation, around 130 Ma. [ABSTRACT FROM AUTHOR]

The Al-Jawf area of northern Saudi Arabia provides spectacular outcrops of Early Devonian carbonate bioherms in the Wadi Murayr and Dumat Al-Jandal areas. These carbonate bioherms belong to the Qasr Member of the Late Pragian-Early Emsian Jauf Formation (~405 Ma) and are surrounded by a bioclastic carbonate succession. The Qasr Member is the first major carbonate unit of the Palaeozoic succession in Saudi Arabia that mainly consists of microbialite carbonates and metazoan reefs exhibiting distinct mound features. These bioherm complexes and their associated carbonate facies are pervasively dolomitized. Stratigraphic, petrographic and geochemical analyses were conducted to determine the facies distribution and interpret their depositional and diagenetic processes. A total of 11 facies are identified from a range of depositional environments within a carbonate platform system, ranging from tidal flats, lagoon, shoal, patch reefs to reef front. The main diagenetic processes are carbonate cementation and dolomitization. Dolomitization occurred as both fabric preserved (mostly in grain-dominated facies) and fabric destructive (mud-dominated facies). The microbialites and coralline sponges facies show poor reservoir with visual porosity less than 5%, but this succession may have a potential to serve as a good source for the underlying and overlying facies. Ooid and peloidal grainstone facies show fair to good visual porosity that locally exceeds 10% with intergranular porosity as the dominant type. However, in the most studied samples, vuggy and intraparticle porosities are observed as the dominant type. [ABSTRACT FROM AUTHOR]

This is an overview of the mode of formation of the Nile Gorge in northern Egypt. It is based on the interpretation of the Shuttle Radar Topography Mission (SRTM) data along with detailed analysis of landsat image, geological map and seismic data. The results show that the current course of the Nile was caused by a differential uplift of two plateaus: Ma'aza, to the east, and Western Desert plateau, to the west of the river. This uplift is caused by dynamic forces resulting from subsurface convection processes. It also contributed to the formation of several drainage systems, basins and structural features. Abundant faults and fractures that are parallel to the Nile Valley on both flanks that are associated with uplift are proven to be contemporaneous with formation of the river. We conclude that understanding of the uplift is crucial to visualizing the Nile course and its geodynamic formation. The information derived from the SRTM data reveals invaluable knowledge in support of the presented remotely sensed geological features. The paper clearly explains the stages of formation of the Nile segments in space and time and structural controls on the path of the Nile River in Egypt. [ABSTRACT FROM AUTHOR]

The Middle Ordovician Rosroe Formation consists of some 1350 m of coarse, mainly siliciclastic to volcaniclastic sedimentary rocks, deposited in a submarine fan environment, and is restricted to the southern limb of the South Mayo Trough, western Ireland. Discrete allochthonous blocks, reaching 5 m in size, are present in the formation at several localities. Conodonts recovered from these blocks, collected from two separate locations, are of late Early and mid Mid Ordovician age. The conodonts have high conodont-alteration indices (CAI 5) indicative of temperatures as high as 300o to max. 480 °C; some found in the Lough Nafooey area have abnormally high indices (CAI 6), which correspond to temperatures of about 360o to max. 550 °C. The oldest fauna is dominated by Periodon aff. aculeatus and characterized by Oepikodus evae typical of the Oepikodus evae Zone (Floian Stage; Stage Slices Fl2-3, Lower Ordovician). The younger conodont assemblage, characterized by Periodon macrodentatus associated with Oistodella pulchra, is referred to the P. macrodentatus conodont Biozone (lower Darriwilian; Stage Slices Dw1-2). The Rosroe conodont assemblages are of Laurentian affinity; comparable faunas are well known from several locations along the east to south-eastern platform margin of Laurentia and the Notre Dame subzone of central Newfoundland, Canada. The faunal composition from the limestone blocks suggests a shelf edge to slope (or fringing carbonate) setting. The faunal assemblages are coeval with, respectively, the Tourmakeady Formation (Floian-Dapingian) and Srah Formation (Darriwilian) in the Tourmakeady Volcanic Group in the eastern part of the South Mayo Trough and probably are derived from the same or similar laterally equivalent short-lived carbonate successions that accumulated at offshore 'peri-Laurentian' islands, close to and along the Laurentian margin. During collapse of the carbonate system in the late Mid Ordovician, the blocks were transported down a steep slope and into deep-water by debris flows, mixing with other rock types now found in the coarse polymict clastics of the Rosroe Formation. The faunas fill the stratigraphical 'gap' between the Lower Ordovician Lough Nafooey Volcanic Group and the upper Middle Ordovician Rosroe Formation in the South Mayo Trough and represent a brief interval conducive to carbonate accumulation in an otherwise siliciclastic- and volcaniclastic-dominated sedimentary environment. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Upper Jurassic Emuerhe Formation was developed with abundant sedimentary facies types in the western section of the Mohe Basin. Based on the systematic sampling and detailed observation on the Emuerhe Formation of this section, the research on the sandstone grain size characteristics of the Emuerhe Formation was carried out with the grain size parameters features (Mz, SK1, KG and σ1), the sensitive components parameters features (SCPGS, SCGSR and SCPV) and the grain size analytical graphs features (grain size frequency curves, grain size cumulative curves, probability cumulative curves and C-M plots). The comprehensive analytical results illustrate that the hydrodynamic energy of the Emuerhe Formation (three times fan delta facies, two times sandy shallow lake microfacies and five times turbidite deposit) in the western section gradually reduced from bottom to top. In addition, the hydrodynamic energy of each fan delta facies gradually enhanced from bottom to top. Based on the analysis of the hydrodynamic conditions of the Emuerhe Formation in the western section, the hydrodynamic conditions evolution history of this section can be divided into five sedimentary phases, namely respectively for the fan delta sedimentary phase, the first-time sandy shallow lake microfacies sedimentary phase, the short-term deep lake subfacies sedimentary phase, the second-time sandy shallow lake microfacies sedimentary phase and the relatively stable deep lake subfacies sedimentary phase from bottom to top. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The upper Viséan-Serpukhovian strata in the type region for the Serpukhovian Stage is an epeiric-sea succession ca. 90 m in thickness. The predominantly Viséan Oka Group (comprising the Aleksin, Mikhailov, and Venev formations) is dominated by photozoan packstones with fluvial siliciclastic wedges developed from the west. The Lower Serpukhovian Zaborie Group is composed of the Tarusa and Gurovo formations. The latter is a new name for the shale-dominated unit of Steshevian Substage age in the studied area. The Zaborie Group is composed of limestones and marls in its lower (Tarusa and basal Gurovo) part and black smectitic to grey palygorskitic shales in the main part of the Gurovo Formation. The Gurovo Formation is capped by a thin limestone with oncoids and a palygorskitic-calcretic palaeosol. The Upper Serpukhovian is composed of a thin (3-12 m) Protva Limestone heavily karstified during a mid-Carboniferous lowstand. The succession shows a number of unusual sedimentary features, such as a lack of high-energy facies, shallow-subtidal marine sediments penetrated by Stigmaria, the inferred atidal to microtidal regime, and palustrine beds composed of saponitic marls. The succession contains many subaerial disconformities characterized by profiles ranging from undercoal solution horizons to palaeokarsts. Incised fluvial channels are reported at two stratigraphic levels to the west of the study area. The deepest incisions developed from the Kholm Disconformity (top of the Mikhailov Formation). This disconformity also exhibits the deepest palaeokarst profile and represents the major hiatus in the Oka-Zaborie succession. The new sea-level curve presented herein shows two major cycles separated by the Kholm Unconformity at the Mikhailov/Venev boundary. The Lower Serpukhovian transgression moved the base-level away from falling below the seafloor so that the section becomes conformable above the Forino Disconformity (lower Tarusa). The maximum deepening is interpreted to occur in the lower dark-shale part of the Gurovo Formation. The base of the Serpukhovian Stage is defined by FADs of the conodont Lochriea ziegleri and the foraminifer Janischewskina delicata in the middle of the sequence VN2. The Aleksinian-Mikhailovian interval is provisionally correlated with the Asbian (Lower-Middle Warnantian) in Western Europe. Based on FODs of Janischewskina typica and first representatives of Climacammina, the Venevian is correlated with the Brigantian in Western Europe. The Tarusian-Protvian interval contains diverse fusulinid and conodont assemblages, but few forms suitable for international correlation. FADs of the zonal conodont species Adetognathus unicornis and Gnathodus bollandensis at several metres above the Protvian base suggest correlation of the entire Zaborie Group and may be the basal Protvian to the Pendleian. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The palynological record from the Permian part of the Çakraz Formation from the Çamdağ area of NW Turkey has been investigated in order to obtain a more precise age assessment than achieved in previous studies. The 'Late Permian' age and a possible age range beginning in the Roadian (mid Permian) were discussed before for sections of palynomorph-bearing strata occurring within the formation. These deposits are now assigned to the late Cisuralian/Guadalupian and considered to be not older than early Kungurian, and not younger than Capitanian. The new age assessment was conducted via a long-distance, intercontinental palynostratigraphic correlation from NW Turkey to South America, where results of radiometric datings were linked to some siliciclastic sections by absolute ages to the chronostratigraphy. Common conspicuous taxa in pollen-dominated assemblages from both regions are Lueckisporites and Vittatina such as Lueckisporites virkkiae, L. latisaccus, L. stenotaeniatus, Vittatina corrugata, V. subsaccata and V. wodehousei. These species co-occur in strata of the northern as well as southern palaeohemisphere settings (NW Turkey and S America). Thus, Lueckisporites latisaccus, L. stenotaeniatus and Vittatina corrugata are, as well as L. virkkiae or V. subsaccata, considered as being cosmopolitan. Due to the more precise palynological dating of part of the Çakraz Formation and surrounding deposits they are here broadly correlated with Permian continental successions from the Southern Alps, Italy, including the Val Daone Conglomerate and the Verrucano Lombardo/Val Gardena Sandstone (Gröden) red beds, and the Rotliegend deposits of Germany. These results support some earlier views regarding the age and stratigraphic equivalences with European deposits. The new age for the Çakraz Formation also supports recent considerations as middle Permian (part Guadalupian), and as Cisuralian for the lower parts of the formation, such as the fossil-bearing section with plants and tetrapod traces further east in NW Turkey, where the unit also crops out. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Two new Permian-aged formations 'Kariz Now Formation' and 'Aliyak Formation' are proposed for a 65-150 m-thick succession in the KarizNow area,with the type section for both (79.5mthick) located 9 kmnortheast of Aliyak village ca. 100 kmsoutheast of Mashhad city, northeastern Iran. The lower Kariz Now Formation is composed of siliciclastics. The age of this Formation is poorly constrained but its correlation with the Shah Zeid Formation in the Central Alborz suggests a possibleAsselian-Hermagorian age for the KarizNow Formation, which implies a hiatus of Yakhtashian-mid Midian (Artinskian-mid Capitanian) age between the siliciclastics of the Kariz Now Formation and carbonates of the disconformably overlying Aliyak Formation. There is also the possibility of a potential correlation of this Formation with the Kungurian Faraghan Formation in the Zagros area. The succeeding Aliyak Formation is mostly composed of carbonate rocks capped by a thin basaltic lava flow. The Aliyak Formation is unconformably overlain by dolostones that are correlated with the Middle Triassic Shotori Formation. Samples were collected from the Kariz Now and Aliyak formations, but fossils were only recovered from the Aliyak Formation. These include calcareous algae, small foraminiferans, fusulinids, crinoid stems and brachiopods. The recovered fusulinid assemblage from the Aliyak Formation is consistent with that of the upper Capitanian Monodiexodina kattaensis-Codonofusiella erki and Afghanella schencki-Sumatrina brevis zones of the Zagros Mountains and with the upper part of the Ruteh Fm in the Alborz Mountains. Although not radiometrically dated, the basaltic lava flow most probably corresponds to similar basaltic lava flows occurring in the uppermost part of the Ruteh Formation in Central Alborz. Thus, the Permian in the studied region developed in a basin that extended westward as far as the Central Alborz. A late Capitanian age for the Aliyak Formation implies it correlates with the Capitanian KS5 in Al Jabal Al-Akhdar in Oman, with Aliyak Unit 5 potentially representing the Permian maximum flooding surface MFS P25. [ABSTRACT FROM AUTHOR]

Introduction: The geological record of the formation and differentiation of our planet has been destroyed by its subsequent evolution, but extremely rare clues may be obtained from other terrestrial planets. Mars provides a unique and accessible example of an early evolutionary path corresponding to that, inaccessible, of our own world. We can investigate it with spacecraft, and samples are available for in-depth analysis on Earth in the form of martian meteorites. So far, the only available martian samples that appear to have recorded the early conditions and the evolution of the planet until the present time are Northwest Africa (NWA) 7034 and its paired stones, nicknamed "Black Beauty". This regolith breccia has been ejected a few million years ago by the formation of a large impact crater, and contains the oldest martian igneous material ever dated: ~4.5 Ga old [1-4]. However, its source and geological context have so far remained unknown. and with it, a region where the earliest geological records of the planet [1-4] are exposed on the surface. Knowing this source region would provide insights into early Mars geological history and crustal extraction [1-4]. This source region may therefore become a high-priority target for detailed orbital analyses and in-situ exploration [5]. Constraints on the meteorite launch site: Following a hypervelocity impact, ejecta materials moving faster than the escape velocity (5 km/s) may get through the martian atmosphere and continue their course into interplanetary space to become martian meteorites [6]. Slower debris fall back on the surface in a radial pattern or ray around the primary crater, forming secondary craters. The presence of 100 meter-size secondaries attests to the freshness of their associated primary craters [7]. Using the size and spatial distribution of more than 90 million impact craters >50 m (both primaries and secondaries) detected using a Crater Detection Algorithm (CDA) [7-8] on the whole surface of Mars from the global Context Camera (CTX) mosaic [9], a previous work [7] identified ray systems of secondary craters <150 m associated with 19 large primary craters, potential source of the ejection of martian meteorites. Here we compare the abundance of K and Th [10-11] as well as the magnetic field intensity and the magnetization of the surface of Mars derived from orbital measurements [12] at the immediate vicinity of each crater candidate with those of the breccia. We also compare the geological context of each of the crater candidates with the chronology and the lithology of the meteorite [e.g. 1-3, 13-14]. The ejection site for Black Beauty: Among the 19 crater candidates investigated, we found that only one match with the characteristics of the meteorite: a 10 km crater located in the north-east of the Terra Cimeria - Sirenum (TCTS) region, between Hesperia Planum and the Tharsis bulge. Our work suggests that clasts contained in the regolith breccia are representative of the TCTS province, making this region a relic of the early crustal processes on Mars [e.g. 15], and thus, a region of high interest for future missions. Details on the identification of the crater source of this unique meteorite, as well a its geological context and broader implications for early crustal processes on Mars will be presented at the conference. [ABSTRACT FROM AUTHOR]