The origin of chert in the Aurignacian of Vogelherd Cave investigated by infrared spectroscopy

The analyses of raw material provenance offers the possibility of tracing short and long-distance raw material transport. So far, most studies of raw material of flint and chert in Europe have been based on macroscopic analyses. We apply infrared spectroscopy to Aurignacian assemblages from Vogelherd cave and to the Magdalenian site Randecker Maar in southwestern Germany. We compare raw material samples from three chert-bearing areas in Germany with archaeological samples from Vogelherd. Our results show that infrared spectroscopy can distinguish between different raw materials. Our archaeological samples from Vogelherd correspond to the sampled geological cherts in terms of their spectral signature. Our comparison of reference samples and archaeological samples highlights problems in commonly used macroscopic identifications of chert raw materials.

Spatiotemporal distribution characteristics, causes, and prevention advice of fatal geohazards in Jiangxi Province, China

Fatal geohazards result in severe losses of life and property worldwide, thus urging many large-scale studies of such geohazards. Further research on hotspots prone to fatal geohazard identified in national-scale studies is critical for government geohazard prevention. It has been pointed out that more detailed small-scale (sub-national) studies are essential for the hotspots (e.g., Jiangxi Province) identified in national-scale studies. However, there are only a few small-scale studies of hotspots and earlier studies have rarely delved into a thorough and detailed analysis of hotspots. In addition, previous studies of fatal geohazards have failed to offer specific geohazard prevention advice, significant for geohazard control policies. To bridge these gaps, this study took advantage of the Jiangxi Inventory of Fatal Geohazards (JIFGH) and employed spatial analysis and the geographical detector to analyze the spatiotemporal characteristics and causes and present prevention advice on fatal geohazards in Jiangxi Province. The study also analyzes the importance of provincial-scale (first-level administrative scale) studies for hotspots identified in national-scale studies. JIFGH includes 386 non-seismically triggered fatal geohazards that caused a total of 979 fatalities in the 1960-2020 period. The temporal trend of fatal geohazards in Jiangxi Province is mainly affected by rainfall and the government geohazard prevention measures. The causes of most fatal geohazards in Jiangxi Province include (i) slope-cutting activities in house construction projects that create steep slopes prone to failure, which threaten the vulnerable residents and buildings nearby and (ii) rainfall that triggers failures of cut slopes. This study not only proposes geohazard prevention advice for Jiangxi Province and tectonically stable areas but also analyzes the significance of provincial-scale studies of hotspots identified in national-scale studies. Therefore, this study contributes to the prevention of fatal geohazards in Jiangxi Province and tectonically stable areas, while also providing an essential reference for other studies of fatal geohazards.

Integrated approach to evaluate unstable rocky slopes: case study of Aqabat Al-Sulbat road in Aseer Province, Saudi Arabia

In this applied research work, the risk of rock instability in the Aqabat Al-Sulbat road section located in the north-west area of Aseer Province in Saudi Arabia was evaluated, and the primary natural trigger factors of rock slope instability on further environmental components (rock slope stability, road network, and urban areas) were estimated using satellite images (Landsat8), digital terrain models, and geoprocessing in geographical information systems software (classification, overlapping algorithms and production thematic mapping in Arctoolbox). Additionally, field geotechnical investigations testing and over-coring drilling sampling allowed the characterization of the section of road in terms of geological structure and environmental components (geology, morphology, road network, lineaments, and hydrology). As a result, rock slope instability vulnerability mapping was simulated using satellite imagery and geographical information systems (GIS) and ranking natural trigger factors using the combined fuzzy Delphi analytical hierarchic process with the technique for order performance by similarity to ideal solution (TOPSIS) as multiple-criteria decision-making (MCDM) techniques. Additionally, many rock layer discontinuity stations were implemented to evaluate rock slope instabilities, and these were visualized using the Dips program and combined with modeling using 3DEC software to predict rock slope failure based on the distinct element method (DEM) at a small scale. Thereafter, safety factors were computed depending on these previous geospatial data. Finally, vulnerability index mapping was combined with rock instability risk mapping for the Aqabat Al-Sulbat road. Within the framework of sustainable development, these results can be used to inform the urban planning of the municipality of Aseer Province.

A Bibliometric Analysis of the Scientific Research on Artisanal and Small-Scale Mining

Mineral resource exploitation is one of the activities that contribute to economic growth and the development of society. Artisanal and small-scale mining (ASM) is one of these activities. Unfortunately, there is no clear consensus to define ASM. However, its importance is relevant in that it represents, in some cases, the only employment alternative for millions of people, although it also significantly impacts the environment. This work aims to investigate the scientific information related to ASM through a bibliometric analysis and, in addition, to define the new lines that are tending to this field. The study comprises three phases of work: (i) data collection, (ii) data processing and software selection, and (iii) data interpretation. The results reflect that the study on ASM developed intensively from 2010 to the present. In general terms, the research addressed focuses on four interrelated lines: (i) social conditioning factors of ASM, (ii) environmental impacts generated by ASM, (iii) mercury contamination and its implication on health and the environment, and (iv) ASM as a livelihood. The work also defines that geotourism in artisanal mining areas is a significant trend of the last decade, explicitly focusing on the conservation and use of the geological and mining heritage and, in addition, the promotion of sustainable development of ASM.

Empirical study of the coupling relationship between biodiversity and environmental geology under different ecological status: Evidence from five typical areas in Guizhou, China

Analyzing the coupling relationship between biodiversity and environmental geology and exploring the factors affecting the coupling degree are of vital significance for the protection and restoration of the ecological environment. In this study, we selected five typical areas (i.e., Caohai, Chishui, Fanjingshan, Maolan, and Guanshanhu) to represent the whole Guizhou Province, China. Based on the coupling coordination degree model, we analyzed their coupling coordination trend. The results showed that the coordinated development stages of the Chishui and Fanjingshan areas both could be categorized as the synchronous development type of primary coordination because of their excellent nature conditions; the Maolan area was categorized as having restrained environmental geology because of its weak environmental geology condition; and the Guanshanhu and Weining areas were strongly affected by human activities, and both could be categorized as having restrained biodiversity. In combination with practical situation, Guizhou province can be categorized into the following three zones: an original ecological zone, a zone with fragile ecological environment, and a zone affected by human activities. Biodiversity conservation measures should be proposed according to the specific ecological situation of these different zones. In this way, the harmonious coexistence of economic development and the ecological environment can be realized.

Groundwater Flow Analysis for Inclined Aquifers

Sedimentary deposits that have water in subsurface groundwater system are not often completely horizontal because of the geological features such as: bedding and folding. These deposits typically overlay on sloped impervious layers, and therefore; additional research is necessary for these situations. In this research an analytical model is presented for groundwater flow on inclined impermeable layer. The presented model is preferable to the Paolowsky method regarding its applicability and accuracy. The Dupuit's assumption is used for the formulation. The presented model can be generalized for the situation, having surficial infiltration into and exfiltration from the groundwater system. Several problems of different slope situations and boundary conditions are addressed by the presented model and the results are shown here. The model is compared with numerical model Seep/w and good agreements are obtained when possible.

Slide type landslide susceptibility assessment of the Büyük Menderes watershed using artificial neural network method

The Büyük Menderes watershed is the largest drainage watershed in Western Anatolia with an area of approximately 26,000 km². In the study area, almost 863 landslides occurred, extending over 222 km² with a mean landslide area of 0.21 km². In this study, landslide susceptibility assessments were carried out using artificial neural network method, which is one of the data-driven methods. In this study, that will contribute to the mitigation or control of the landslides caused by the reasons controlling the spatial and temporal distribution of landslides created in the GIS and MATLAB environment by using scientific and technological approaches within the framework. Since derivative activation function is also used in back-propagation artificial neural networks, its derivative is easily calculated in order not to slow down the calculation. Levenberg-Marquardt back-propagation (LM), resilient back propagation back-propagation (trainrp), scaled conjugate gradient back-propagation (trainscg), conjugate gradient with Powell/Beale restarts back-propagation (traincgb), and Fletcher-Powell conjugate gradient back-propagation (traincgf) algorithms are used, which constantly interrogate the link between the input parameter and the result output, and at least one cell's output is given as an input to any other cell. Geology, digital elevation model, slope, topographic wetness index, roughness index, plan, profile curvatures, and proximity to active faults and rivers were used as landslide conditioning factors. In susceptibility assessments, landslides were separated by 70% analysis, 15% test, and 15% validation datasets by random selection method. The performances of the landslide susceptibility maps were assessed by the area under the ROC curve (AUC), accuracy (ACC), precision, recall, F1 score, Kappa test error histogram, and confusion matrix, respectively. The area under the receiver operating characteristic curves, analysis, testing, validation, landslides, and study areas were found between 0.873 and 0.911. The susceptibility map had a high prediction rate in which high and very high susceptible zones corresponded to 26% of the study area including 82% of the recorded landslides.

Analysis on the spatial differentiation characteristics of poverty risk caused by disaster under the stress of geological disasters: a case study of Sichuan Province

Research on the poverty risk caused by geological disasters in disaster-prone areas is a useful exploration to coordinate social economic development with disaster prevention and reduction, and is of great significance to the regional sustainable development. Based on statistical data and spatial data, this paper takes Sichuan Province as the typical research area. Remote sensing and geographic information technology are used to study the poverty risk caused by disasters based on the quantitative evaluation of geological disasters risk and regional development level. The spatial differentiation characteristics of poverty risk caused by disasters are explored on the 1 km × 1 km grid scale. The results indicate that (1) the overall risk of geological disasters in Sichuan Province is relatively high, with high and relatively high risk areas accounting for more than 40% and low and relatively low risk areas accounting for less than 30%. The risks in Mountain and Ravine Areas are significantly higher than other areas. (2) The regional development level in Sichuan Province is relatively high, but with significant spatial differences. The development level of high-altitude areas and remote mountainous areas is quite different from that of the Chengdu Plain in the middle Sichuan Province. The uneven development in the east, middle, and west is a prominent problem. (3) The poverty risk caused by disasters is high, and the spatial pattern presents a characteristic of "high in the west and low in the east" with high positive spatial correlation. High-High Cluster Areas are mainly distributed in western and southwestern Sichuan. Low-Low Outlier Areas are mainly distributed in Chengdu Plain and Hilly Areas of Sichuan Basin. High-Low Outlier and Low-High Outlier Areas occupy a relatively small percentage with scattered distribution. This paper provides some theoretical support for policy formulation and management of coordinated development of regional socioeconomic and ecological environment.

Numerical modeling as a tool for evaluating the renewability of geothermal resources: the case study of the Euganean Geothermal System (NE Italy)

Renewable natural resources are strategic for reducing greenhouse gas emissions and the human footprint. The renewability of these resources is a crucial aspect that should be evaluated in utilization of scenario planning. The renewability of geothermal resources is strictly related to the physical and geological processes that favor water circulation and heating. In the Veneto region (NE Italy), thermal waters of the Euganean Geothermal System are the most profitable regional geothermal resource, and its renewability assessment entails the evaluation of fluid and heat recharge, regional and local geological settings, and physical processes controlling system development. This renewability assessment is aimed at defining both the importance of such components and the resource amount that can be exploited without compromising its future preservation. In the second part of the twentieth century, the Euganean thermal resource was threatened by severe overexploitation that caused a sharp decrease in the potentiometric level of the thermal aquifers. Consequently, regulation for their exploitation is required. In this work, the renewability of the Euganean Geothermal System was assessed using the results from numerical simulations of fluid flow and heat transport. The simulations were based on a detailed hydrogeological reconstruction that reproduced major regional geological heterogeneities through a 3D unstructured mesh, while a heterogeneous permeability field was used to reproduce the local fracturing of the thermal aquifers. The model results highlight the role played by the resolved structural elements, in particular the subsurface high-angle faults of the exploitation field, and by the anomalous regional crustal heat flow affecting the central Veneto region.

Resolving the History of Life on Earth by Seeking Life As We Know It on Mars

An origin of Earth life on Mars would resolve significant inconsistencies between the inferred history of life and Earth's geologic history. Life as we know it utilizes amino acids, nucleic acids, and lipids for the metabolic, informational, and compartment-forming subsystems of a cell. Such building blocks may have formed simultaneously from cyanosulfidic chemical precursors in a planetary surface scenario involving ultraviolet light, wet-dry cycling, and volcanism. On the inferred water world of early Earth, such an origin would have been limited to volcanic island hotspots. A cyanosulfidic origin of life could have taken place on Mars via photoredox chemistry, facilitated by orders-of-magnitude more sub-aerial crust than early Earth, and an earlier transition to oxidative conditions that could have been involved in final fixation of the genetic code. Meteoritic bombardment may have generated transient habitable environments and ejected and transferred life to Earth. Ongoing and future missions to Mars offer an unprecedented opportunity to confirm or refute evidence consistent with a cyanosulfidic origin of life on Mars, search for evidence of ancient life, and constrain the evolution of Mars' oxidation state over time. We should seek to prove or refute a martian origin for life on Earth alongside other possibilities.

Contributing Areas to Domestic Wells in Dipping Sedimentary Rocks under Extreme Recharge Events

We use particle tracking to determine contributing areas (CAs) to wells for transient flow models that simulate cyclic domestic pumping and extreme recharge events in a small synthetic watershed underlain by dipping sedimentary rocks. The CAs consist of strike-oriented bands at locations where the water table intersects high-hydraulic conductivity beds, and from which groundwater flows to the pumping well. Factors that affect the size and location of the CAs include topographic flow directions, rock dip direction, cross-bed fracture density, and position of the well relative to streams. For an effective fracture porosity (n_e ) of 10^-4 , the fastest advective travel times from CAs to wells are only a few hours. These results indicate that wells in this type of geologic setting can be highly vulnerable to contaminants or pathogens flushed into the subsurface during extreme recharge events. Increasing n_e to 10^-3 results in modestly smaller CAs and delayed well vulnerability due to slower travel times. CAs determined for steady-state models of the same setting, but with long-term average recharge and pumping rates, are smaller than CAs in the models with extreme recharge. Also, the earliest-arriving particles arrive at the wells later in the steady-state models than in the extreme-recharge models. The results highlight the importance of characterizing geologic structure, simulating plausible effective porosities, and simulating pumping and recharge transience when determining CAs in fractured rock aquifers to assess well vulnerability under extreme precipitation events.

Evaluation of soil-gas radon concentrations from different geological units with varying strata in a crystalline basement complex of southwestern Nigeria

The aim of this study is to determine the variation of soil-gas radon concentrations from different rock formations in Ogbomoso, southwestern Nigeria. The radon concentrations at different five geological domains in Ogbomoso are determined with respect to depth. The measurements varied from the surface (0 cm) to 100 cm depth, with an interval of 20 cm. At all the geological domains (Porphyroclastic, Granite, Quartzite, Migmatite and Banded gneiss), radon has its minimum emission over migmatite at 0 cm, while its maximum emissions occured over granite and banded gneiss at 80 cm. The overall soil-gas radon concentrations in Ogbomoso varied from 0.06 to 26.5 kBq/m³, which is within the natural limit of 0.4 to 40 kBq/m³ based on the International Commission on Radiological Protection's recommendation. An F-ratio of 6.989 and a p-value of 0.001 were obtained for the first inferential hypothesis, while an F-ratio of 2.489 and a p-value of 0.076 were obtained for the second inferential hypothesis using ANOVA test. The post hoc (using Tukey HSD and Duncan) tests revealed that at 60 + cm, depth controls the level of radon concentrations being emanated from the subsurface. The pollution index in Ogbomoso is of level 1 at 80 cm and level 0 (safe limit) at other depths. In conclusion, the soil-gas radon emission depends on the local geology and lithological sequences (depths). Cracks that could act as passage for indoor radon at the floors of the buildings around the polluted zones should be avoided in order to have a sustainable city.

Identification of precipitation trend and landslide susceptibility analysis in Miandoab County using MATLAB

Iranian plateau is a seismically active region. Within this region, northwestern Iran is of high importance. Before proper planning for mitigating the earthquake-induced hazards can be achieved, it is necessary to identify high-risk areas in terms of susceptibility to earthquakes. In this study, landslide susceptibility in Miandoab Country was modeled using the so-called random forest algorithm (RFA) in MATLAB based on records acquired at 67 earthquake hotspots considering 9 factors affecting the earthquake occurrence (i.e., height, slope, direction, distance from fault, distance from river, distance from road, land use, geology, and precipitation). Predictive power of the model and validity of its results were evaluated using relative operating characteristic (ROC) curve and area under the curve (AUC). The assessment results showed very good accuracy of the model (0.97). It was further found that digital height layer, geology, and distance from fault impose the largest contributions into earthquake potential. The results also showed that 53%, 8.3%, and 38.4% of the study area were classified as being at low risk, moderate risk, and high risk of earthquake. Among other climatic elements, the precipitation exhibits the largest fluctuations; we proceeded to evaluate precipitation trends in the study area for a statistical period of 30 years. This was practiced by implementing Mann-Kendall nonparametric test in MATLAB. This subject-matter is especially important in Iran where the annual precipitation level is as low as 250 mm. The results showed that the precipitation follows an increasing trend in the region.

The earth vibrates with analogies: The Dirac sea and the geology of the vacuum

The debate around analogy in modern physics that focuses on its role as a logical inference often correspondingly overlooks its historical dimension and the other equally important functions and aspects that are intertwined with this dimension. Inspired by a close investigation of the primary sources and archival material of a few historical actors, this paper lays out a framework on analogy-making which preserves as much as possible its historical complexity. While not losing sight of the logical role, our framework puts a special emphasis on the heuristic process, and aims at offering to the historian and philosopher of science as well as the physicist some tools to capture the subtle functions of analogical reasoning involved in such a process. After having traced it out theoretically, we make use of this framework to interpret the growth of the ideas of two remarkable physicists dealing with the multifaceted notion of vacuum in 20th century physics. We first consider the trajectory followed by John A. Wheeler, between the 1960s and 1970s, towards (in his own words) a "geology of the vacuum"; and then examine, starting from the hitherto neglected Japanese reception of the idea of Dirac sea in the early 1930s, the pathway that led Yoichiro Nambu to the discovery of spontaneous symmetry breaking.

Developing a pan-European high-resolution groundwater recharge map - Combining satellite data and national survey data using machine learning

Groundwater recharge quantification is essential for sustainable groundwater resources management, but typically limited to local and regional scale estimates. A high-resolution (1 km × 1 km) dataset consisting of long-term average actual evapotranspiration, effective precipitation, a groundwater recharge coefficient, and the resulting groundwater recharge map has been created for all of Europe using a variety of pan-European and seven national gridded datasets. As an initial step, the approach developed for continental scale mapping consists of a merged estimate of actual evapotranspiration originating from satellite data and the vegetation controlled Budyko approach to subsequently estimate effective precipitation. Secondly, a machine learning model based on the Random Forest regressor was developed for mapping groundwater recharge coefficients, using a range of covariates related to geology, soil, topography and climate. A common feature of the approach is the validation and training against effective precipitation, recharge coefficients and groundwater recharge from seven national gridded datasets covering the UK, Ireland, Finland, Denmark, the Netherlands, France and Spain, representing a wide range of climatic and hydrogeological conditions across Europe. The groundwater recharge map provides harmonised high-resolution estimates across Europe and locally relevant estimates for areas where this information is otherwise not available, while being consistent with the existing national gridded datasets. The Pan-European groundwater recharge pattern compares well with results from the global hydrological model PCR-GLOBWB 2. At country scale, the results were compared to a German recharge map showing great similarity. The full dataset of long-term average actual evapotranspiration, effective precipitation, recharge coefficients and groundwater recharge is available through the EuroGeoSurveys' open access European Geological Data Infrastructure (EGDI).

The proper choice of proxies for relevant strontium isotope baselines used for provenance and mobility studies in glaciated terranes - Important messages from Denmark

Strontium (Sr) isotope based provenance and mobility studies of ancient humans and animals necessitate representative isoscapes/baselines. However, regions/terranes that were shaped and affected by glaciers during the last Ice Ages and are covered by glaciogenic sediments present a challenge with regards to the choice of suitable surface proxy archives. Recent studies proposed that only ⁸⁷Sr/⁸⁶Sr signatures from pristine areas are relevant for this purpose. To test this theory, 160 new Sr concentrations [Sr] and ⁸⁷Sr/⁸⁶Sr signatures composed from ~960 subsamples of soil leachates and plants, complemented with 55 surface waters from agriculturally unaffected pristine forest sites from all over Denmark (island of Bornholm excluded) were analyzed. The results reveal that average ⁸⁷Sr/⁸⁶Sr signatures of all three proxies (plants: 0.7115 ± 0.0025; 2σ, n = 162; soil leachates: 0.7118 ± 0.0037; 2σ; n = 161, surface waters: 0.7104 ± 0.0030; 2σ, n = 55) are elevated compared to larger water bodies (creeks, rivers, lakes). In mixing diagrams, the data converge in a shared high [Sr] low ⁸⁷Sr/⁸⁶Sr endmember, which points to either remnant natural carbonates and/or organic components retaining carbonate Sr in the studied Podzols/Luvisols. The indications for more abundant carbonates in the past, compared to today's acid leached soils, implies that ⁸⁷Sr/⁸⁶Sr values measured from pristine forest locations and heathlands do not adequately reflect the biosphere compositions that prevailed ~12,000-2000 thousand years ago. Consequently, pristine forests in Denmark seem to be unsuitable proxy archive environments for constructing Sr isotope baselines for determining the provenance and mobility of ancient humans and animals. Hence, ⁸⁷Sr/⁸⁶Sr values measured in these pristine areas are non-representative and inadequate, and their use will lead to wrong interpretations. Finally, our study sheds light on the complexity of defining relevant and representative isoscapes/baselines in significantly changing environments and areas where the surface biosphere conditions do not necessary reflect the underlying geology.

Design of a Comprehensive Assessment Model for the Stability and Engineering Geology of Slope Based on Improved Convolutional Neural Network

The geological mechanics, geotechnical characteristics, and hydrogeological conditions of slopes are complex and changeable, so their stability assessment is a complicated system; their traditional engineering geological assessment does not consider the opposition of the system, the uncertainty of performance indicators, and the ambiguity of index classification, being easy to distort results due to the ambiguity. Improved convolutional neural network (CNN) has outstanding advantages in analyzing problems with randomness and fuzziness. It can perform unified numerical processing on slope assessment indicators with precise values, interval values, and qualitative judgment values, making the traditional qualitative description is transformed into quantitative calculation. Therefore, on the basis of summarizing and analyzing previous research works, this paper expounded the research status and significance of the comprehensive assessment model for slope stability and engineering geology; elaborated the development background, current status, and future challenges of the improved CNN; introduced the methods and principles of the model structure, convolutional layer design, and data flow optimization of the improved CNN; performed the assessment index system establishment and index weight determination; established the mathematical assessment model for slope stability; conducted the assessment module design for slope stability based on the improved CNN; analysed the importance of individual factors to the comprehensive engineering geological characteristics; discussed the determination of assessment value of comprehensive unit engineering geological characteristics; explored the assessment module design for slope engineering geology based on the improved CNN; and finally carried out an engineering application and its result analysis. The study results show that the improved CNN can select some universal and objective factors according to the actual conditions of slopes, including topography, stratum lithology, geological structure, atmospheric rainfall, groundwater, engineering activities, setting up factor sets and judgment sets, and making fuzzy inferences. The comprehensive assessment model can use appropriate mathematical methods to judge the pros and cons of slope's stability and engineering geology according to certain principles and standards, and grade the results and identify the most important geological problems. The results of this paper provide a reference for further researches on the design of a comprehensive assessment model for slope stability and engineering geology based on the improved CNN.

The Radiation Environment of Ceres and Implications for Surface Sampling

Ceres is a large water-rich dwarf planet located within the asteroid belt. Its surface displays evidence of material sourced from a deep subsurface liquid brine layer within recent geologic time, making it a candidate ocean world with possible present-day activity. However, Ceres lacks a substantial atmosphere and likely does not possess a global magnetic field. Therefore, any material emplaced or exposed on the surface will be subject to weathering by charged particles of solar and galactic origin. We have evaluated the effect of charged particle radiation on material within the near-surface of Ceres and find that the timescale for radiation-induced modification and destruction of organics and endogenic material is ∼100 Myr to 1 Gyr within the top 10-20 cm of the surface. Furthermore, we find that the timescale for sterilization of any putative living organisms contained within material at these depths is <500 kyr. Future missions to the surface may therefore consider targeting regions with geologic ages that fall between these two timescales to avoid the risk of backward contamination while ensuring that sampled material is not heavily radiation processed.

Comparative soft-tissue preservation in Holocene-age capelin concretions

Determining how soft tissues are preserved and persist through geologic time are continuing challenge because decay begins immediately after senescence while diagenetic transformations generally progress over days to millions of years. However, in recent years, carbonate concretions containing partially-to-fully decayed macroorganisms have proven to be remarkable windows into the diagenetic continuum revealing insights into the fossilization process. This is because most concretions are the result of biologically induced mineral precipitation caused by the localized decay of organic matter, which oftentimes preserves a greater biological signal relative to their host sediment. Here we present a comparative lipid biomarker study investigating processes associated with soft-tissue preservation within Holocene-age carbonate concretions that have encapsulated modern capelin (Mallotus villosus). We focus on samples collected from two depositional settings that have produced highly contrasting preservation end-members: (1) Kangerlussuaq, Greenland: a marine environment, which, due to isostatic rebound, has exposed strata containing concretions exhibiting exceptional soft-tissue preservation (6-7 kya), and (2) Greens Creek, Ottawa, Canada: a paleo brackish-to-freshwater marine excursion containing concretions exhibiting skeletal remains (~11 kya). Lipid biomarker analysis reveals endogenous capelin tissues and productive waters at Kangerlussuaq that are in sharp contrast to Greens Creek concretions, which lack appreciable capelin and environmental signals. Comparable distributions of bacterial fatty acids and statistical analyses suggest soft-tissue preservation within concretions is agnostic to specific heterotrophic decay communities. We, therefore, interpret preservation within carbonate concretions may represent a race between microbially induced authigenic precipitation and decay. Namely, factors resulting in exceptional preservation within concretions likely include: (1) organic matter input, (2) rate of decay, (3) carbonate saturation, (4) porewater velocity, and (5) rate of authigenic (carbonate) precipitation resulting in arrested decay/bacterial respiration due to cementing pore spaces limiting the diffusion of electron acceptors into the decay foci.

Coupling coordination relationship between geology-geomorphology and ecology in Northeast China

Northeast China is an important ecological barrier and commodity grain base in China. The coupling coordination relationship between geology–geomorphology and ecology has become a critical background condition for ecosystem protection and sustainable development. Taking Northeast China as a case (accounting for about 13% of China’s land area), 9 divisions are divided according to the characteristics of regional ecology and geology–geomorphology, and 17 indicators are selected to build an evaluation index system. Methods of analytic hierarchy process, entropy weight and game theory are used to determine the index weights. Based on the coupling coordination degree (CCD) model, the spatial coupling coordination characteristics of geology–geomorphology and ecology are studied. The variation characteristics of the Normalized Difference Vegetation Index (NDVI) are evaluated by Sen+Mann–Kendall (Sen+MK) method. Our results are as follows. (1) The coupling between geology–geomorphology and ecology is strong, but the spatial differentiation of CCD is obvious. Nine divisions are evaluated as two high–level, three medium–level and three low–level coordination types and one mild imbalance type. (2) The plain divisions Ⅰ and Ⅳ where the typical black soil belt is located are high coordination types. Restricted by geology–geomorphological conditions or ecological conditions, mountain divisions Ⅲ and Ⅶ and plain division Ⅴ are moderate coordination types, mountain divisions Ⅱ and Ⅷ and plateau division Ⅸ are low coordination types, and mountain division Ⅵ is mild imbalance type. (3) The variation trend of NDVI shows a significant increase in divisions Ⅲ, Ⅴ, Ⅰ, Ⅱ and Ⅶ. it shows a significant decrease in part of divisions Ⅳ, Ⅵ, Ⅷ and Ⅸ, and ecological management and construction should be strengthened in these divisions. The research shows that the CCD model method is feasible for evaluating the relationship between geology–geomorphology and ecology and can provide eco–geological background information for Northeast China.

Similarity Simulation on the Movement Characteristics of Surrounding Rock and Floor Stress Distribution for Large-Dip Coal Seam

The question of how to mine safely in close multi coal seams is the main concern for coal operators, in particular for large-dip coal seams with complex geological and mechanical conditions. This paper presents a detailed similarity simulation on the movement characteristics of the overburden and the stress distribution of underlying strata in terms of a specific coal mine in the Tielieke mining area of the Kubai coalfield via a three-dimensional photogrammetry system and a high-speed static resistance analyzer. The results show that the overburden strata are asymmetrically deformed around the coal pillar and the fracture area is perpendicular to the longwall with an "M" shape when deeper coal is mined. Moreover, the asymmetric movement of overburden results in the non-uniform distribution of stress on the floor of the coal pillar and ribs. In particular, stress is closely related to the location of the longwall, and stress of the coal pillar is much larger when it is closer to the deep side. The floor stress relief degree of the longwall in the deep zone is higher than that of its counterparts, providing a theoretical foundation for a reasonable layout and a support technique for roadways. The main contribution of this research that it can be used as a reference in maintaining the integrity of surrounding rock for large-dip coal seams with close distances.

Spatial modeling of land subsidence using machine learning models and statistical methods

Land subsidence causes many problems every year and damages residential areas and agricultural lands. The purpose of this study is to prepare a susceptibility map to the phenomenon of land subsidence in the central and eastern plains of Fars province in Iran using statistical and machine learning models. Initially, with a wide inspection, the locations of land subsidence in the study region were recorded using the global positioning system (GPS), and a spatial distribution of subsidence was provided then for building and evaluating learning models; the data was partitioned into two sections of calibration (70%) and testing (30%) dataset. In the following stage, the maps of the factors affecting the land subsidence were prepared using basic information (geological and topographic maps and satellite images) in raster format, and the relationship between land subsidence locations and the effective factors including slope percentage, slope aspect, distance from the road, distance from the river, land use, plan curvature, topographic wetness index, geology (lithological units), distance from the faults, and groundwater level changes was considered in the study area. To investigate the multicollinearity between independent variables, tolerance and variance inflation factor (VIF) measures were used, and to prioritize the effective factors, the random forest (RF) algorithm was applied. The results indicated that the most important factors affecting land subsidence were groundwater level changes, land use, height, distance from the fault, distance from the river, and topographic wetness index, respectively. For further analysis, a land subsidence susceptibility zoning map was prepared using logistic regression (LR), random forest (RF), boosting regression tree (BRT), and support vector machine (SVM) models, and the results were evaluated. The evaluation results indicated that the models mentioned have high accuracy in modeling land subsidence such that the boosting regression tree and the logistic regression have high (0.873 and 0.853, respectively) and the random forest and support vector machine models have very high accuracy (0.953 and 0.926, respectively). The findings of this study indicated that the machine learning techniques and prepared maps can be applied for land use planning, groundwater management, and management of the study area for future agriculture tasks.

Susceptibility Analysis of Geohazards in the Longmen Mountain Region after the Wenchuan Earthquake

Multitemporal geohazard susceptibility analysis can not only provide reliable results but can also help identify the differences in the mechanisms of different elements under different temporal and spatial backgrounds, so as to better accurately prevent and control geohazards. Here, we studied the 12 counties (cities) that were severely affected by the Wenchuan earthquake of 12 May 2008. Our study was divided into four time periods: 2008, 2009–2012, 2013, and 2014–2017. Common geohazards in the study area, such as landslides, collapses and debris flows, were taken into account. We constructed a geohazard susceptibility index evaluation system that included topography, geology, land cover, meteorology, hydrology, and human activities. Then we used a random forest model to study the changes in geohazard susceptibility during the Wenchuan earthquake, the following ten years, and its driving mechanisms. We had four main findings. (1) The susceptibility of geohazards from 2008 to 2017 gradually increased and their spatial distribution was significantly correlated with the main faults and rivers. (2) The Yingxiu-Beichuan Fault, the western section of the Jiangyou-Dujiangyan Fault, and the Minjiang and Fujiang rivers were highly susceptible to geohazards, and changes in geohazard susceptibility mainly occurred along the Pingwu-Qingchuan Fault, the eastern section of the Jiangyou-Dujiangyan Fault, and the riparian areas of the Mianyuan River, Zagunao River, Tongkou River, Baicao River, and other secondary rivers. (3) The relative contribution of topographic factors to geohazards in the four different periods was stable, geological factors slowly decreased, and meteorological and hydrological factors increased. In addition, the impact of land cover in 2008 was more significant than during other periods, and the impact of human activities had an upward trend from 2008 to 2017. (4) Elevation and slope had significant topographical effects, coupled with the geological environmental effects of engineering rock groups and faults, and river-derived effects, which resulted in a spatial aggregation of geohazard susceptibility. We attributed the dynamic changes in the areas that were highly susceptible to geohazards around the faults and rivers to the changes in the intensity of earthquakes and precipitation in different periods.

Spatio-temporal evolution of post-seismic landslides and debris flows: 2017 Ms 7.0 Jiuzhaigou earthquake

Spatio-temporal evolution of post-seismic landslides and debris flows provides a new perspective to understand post-earthquake evolution of geological environments and landscapes, and to instruct cascaded catastrophic hazard mitigation and post-disaster reconstruction. However, limited earthquake events have been investigated for post-earthquake geohazard evolution. This work reports the geohazard evolution after the 2017 M_s 7.0 Jiuzhaigou earthquake considering the effects of the earthquake, geology, terrain, meteorology, hydrology, and human engineering activity. Some new viewpoints are suggested. (1) Landslide and debris flow activity intensified in the first year following the earthquake under the effects of the antecedent earthquake, precipitation, fault tectonics, human engineering activity, and fluvial networks. (2) Landslide and debris flow activity declined rapidly in the second year as a result of dramatically reduced sediments, declined rainfall, and self-healed slopes. (3) The significant decay of landslide and debris flow activity and the prominent reduction of loose deposits indicate that the geological environment was gradually restoring. (4) Although the hazard effect mitigation and geological environment restoration were ongoing (in the absence of rainstorm events) to attain a new balance, the geoenvironment has not returned to the pre-earthquake level because of widespread unrecovered geohazards and the remaining loose deposits on hillslopes or in channels. (5) The geological environment after the Jiuzhaigou earthquake may re-equilibrate and return to the pre-earthquake level more quickly than after the Kashmir, Chi-Chi, Gorkha, Wenchuan, and Murchison earthquakes. This work provides new knowledge pertaining to geohazard evolution after a strong earthquake and to profound impacts of a catastrophic earthquake on geological environment and landscape.

Distribution of rare earth elements in soils of contrasting geological and pedological settings to support human health assessment and environmental policies

Establishing quality reference values (QRVs) for rare earth elements (REEs) in soils is essential for the screening of these emergent contaminants. Currently, Brazil has the second-largest reserve of REEs, but data regarding background concentrations and distributions in soils remain scarce. The aim of this study was to establish the QRVs and assess the spatial distribution of REEs in soils, including REE fractionations and anomalies in (Piauí) state (251,529.186 km²), northeastern Brazil. This study reports the most detailed data on REE geochemistry in Brazilian soils. A total of 243 composite soil samples was collected at 0-20 cm depth. The mean background concentrations in soils followed the abundance of the earth's upper crust: Ce > La > Nd > Pr > Sm > Dy > Gd > Er > Yb > Eu > Tb > Lu. The ∑REEs (mg kg^-1) showed the following order based on the individual mesoregions of Piauí state: Southeast (262.75) > North and Central-North (89.68) > Southwest (40.33). The highest QRVs were observed in the Southeast mesoregion. The establishment of QRVs based on the mesoregion scale improves data representativeness and the monitoring of natural REE values by identifying hot spots. Geostatistical modeling indicated significant local variability, especially in the Southeast mesoregion. The levels of these elements in this spatial zone are naturally higher than the other values across Piauí state and the mesoregion itself and indicate a high potential to exceed the QRVs. Our approach provides much needed data to help strengthen policies for both human health and environmental protection.