Spatial Distribution Of Resistivity Research Articles

Pyrethroid resistance distribution in Triatoma infestans and environmental association along the Argentine endemic zone

Insecticide resistance is considered a barrier to chemical control of Triatoma infestans, the main vector of Chagas disease in the Southern Cone of South America. Although initiatives to reduce the incidence of the disease in the region have integrated different strategies, they have mainly relied on vector elimination using pyrethroid insecticides such as deltamethrin. Reports of pyrethroid resistance in connection with T. infestans control failures first emerged in northern Argentina and southern Bolivia. Recently, a mosaic pyrethroid-resistant focus has been described in the center of the Argentine Gran Chaco (Department of General Güemes, Chaco Province), characterized by the presence of susceptible and very highly resistant populations in the same area. The involvement of different resistance mechanisms has been proposed, together with the contribution of environmental variables that promote the toxicological heterogeneity described. In the endemic zone of Argentina, however, new questions arise: Are there any other clusters of resistance? Is there a relationship between the distribution of resistance and environmental variables (as has been observed at smaller scale)? We studied toxicological data from insects collected and analyzed at 224 localities between 2010 and 2020 as part of the resistance monitoring conducted by the Chagas National Program. The sites were classified according to the survival rate of insects exposed to a discriminant dose of deltamethrin: 0–0.19 were considered susceptible, 0.2–0.79 low-resistance, and 0.8–1 high-resistance. Localities were georeferenced to describe the spatial distribution of resistance and to identify environmental variables (demographics, land use, urbanization, connectivity, and climate) potentially associated with resistance. We used Generalized Linear Models (GLMs) to examine the association between resistance and environmental predictors, selecting error distributions based on the response variable definition. For the entire period, 197 susceptible localities were distributed across the endemic zone. Localities with different survival rates were found throughout the area; 9 high-resistance localities circled the two previously identified resistant foci, and 18 low-resistance in 6 provinces, highlighting their relevance for control planning. Precipitation variables were linked to resistance in all the GLMs evaluated. Presence/absence models were the most accurate, with precipitation, distance from the capital city, and land use contributing to the distribution of resistance. This information could be valuable for improving T. infestans control strategies in future scenarios characterized by unpredictable changes in land use and precipitation.

Wide-range resistivity characterization of semiconductors with terahertz time-domain spectroscopy

Resistivity is one of the most important characteristics in the semiconductor industry. The most common way to measure resistivity is the four-point probe method, which requires physical contact with the material under test. Terahertz time domain spectroscopy, a fast and non-destructive measurement method, is already well established in the characterization of dielectrics. In this work, we demonstrate the potential of two Drude model-based approaches to extract resistivity values from terahertz time-domain spectroscopy measurements of silicon in a wide range from about 10−3 Ωcm to 102 Ωcm. One method is an analytical approach and the other is an optimization approach. Four-point probe measurements are used as a reference. In addition, the spatial resistivity distribution is imaged by X-Y scanning of the samples to detect inhomogeneities in the doping distribution.

Widespread acaricide resistance and multi-resistance in Rhipicephalus microplus in Ecuador and associated environmental and management risk factors

Rhipicephalus microplus is a cattle tick widely distributed in tropical and subtropical areas. Various acaricides are used and applied to control the ticks, but resistance is common. The objectives of this study were to evaluate the spatial distribution of resistance to the most commonly applied acaricides (amitraz, ivermectin, and alpha-cypermethrin) in ticks and assess potential risk factors associated with tick resistance in a strip between ±0.5° latitude of the continental part of Ecuador. Larval package tests were used to evaluate the level of acaricide resistance in 96 cattle farms. The association between 11 farm management and 8 ecological variables and acaricide resistance and multi-resistance was evaluated. Dose-response models were used to study the level of resistance. 72 % (69/96), 70 % (67/96), and 64 % (61/96) of farms had ticks resistant to amitraz, ivermectin, and alpha-cypermethrin, respectively. Multi-resistance was also widespread. Larger herds and dairy farms had a significantly higher probability of resistance for three commonly used acaricides. Environmental factors related to rainfall were also associated with acaricidal resistance presence. Ivermectin resistance was associated with use of the acaricide (OR = 8.9909; 7.7519-10.2300), mean temperature (OR = 1.3205;1.0742-1.6799)), and inversely associated with paddock rotation (OR = 0.1753; 0.0294-0.7836), and precipitation of the wettest month (BIO13) (OR = 0.9903; 0.9839-0.9957); amitraz with use of the acaricide (OR = 4.3934; 3.3679-5.4188), precipitation seasonality (BIO15) (OR=0.9742; 0.9542-0.9925), and precipitation (OR = 0.9995; 0.9994-0.9999); and alpha-cypermethrin with precipitation (OR=0.9995; 0.9990-0.9999) and use of the acaricide (OR = 14.4597; 13.4343-15.4852). In conclusion, acaricide resistance was widespread in our study area. Better-integrated tick management and environmentally friendly control strategies are required to reduce the use of acaricides while limiting tick-associated damage in herds.

The biogeography of embolism resistance across resource gradients in the Amazon

AbstractAimUnderstanding tree mortality under climate change‐induced droughts requires knowledge of hydraulic trait distribution across environmental gradients. The spatial distribution of embolism resistance (i.e., P50), a key trait linked to hydraulic failure, is currently unknown across the Amazon. Here, we tested how precipitation, water table depth (WTD) and soil fertility interact as filters modulating the geographic hydraulic trait distribution.LocationFour sites in three key regions across the Amazon basin: Central, Western peripheral area and Brazilian Shield.Time PeriodPresent.Major Taxa StudiedTree species.MethodWe measured hydraulic vulnerability curves of 64 tree species (165 individuals) using an orthogonal design contrasting seasonal precipitation gradients, soil fertility and WTD. To estimate the geographical distribution of hydraulic traits for the basin scale, we use the coefficients of the best generalized linear model, projected on a 1 km grid in each environmental layer.ResultsWe show that WTD and soil fertility are the main drivers of embolism resistance, while precipitation has a secondary effect. Trees in shallow WTD and fertile soils had riskier hydraulic strategies. Our spatial projection identified the Amazonian southern band and valleys across the basin as the most vulnerable areas. High soil fertility in these regions increases the variability of hydraulic traits and thus uncertainty in predictions of drought responses.Main ConclusionAt the scale of the Amazon basin, we show that dominant tree species traits converge toward hydraulic resistance when resource (water and nutrients) levels are low and towards hydraulic vulnerability (but with higher trait variability) when resources increase. These results highlight the importance of WTD and soil fertility in structuring hydraulic traits and their effects on tree mortality under climate change‐induced droughts. Further empirical tests covering a wider spatial range and more tree species will help validate our biogeographical distribution model.

Frequency and spatial distribution of knock-down resistance (kdr) to pyrethroids in multiple oilseed rape pest species of the genus Ceutorhynchus.

The protection of European oilseed rape (OSR) from damaging insects relies on pyrethroid insecticides, but the development of resistance in key coleopteran pests such as the pollen beetle (Brassicogethes aeneus) and the cabbage stem flea beetle (Psylliodes chrysocephala) has resulted in reduced effectiveness of these insecticides. The sodium channel gene mutation L1014F knock-down resistance (kdr) is a contributing factor in resistance to pyrethroids in B. aeneus and P. chrysocephala, but little is known about the status of resistance in weevils of the genus Ceutorhynchus (Coleoptera: Curculonidae). Therefore, the present study investigated pyrethroid susceptibility and the presence of the kdr mutation in four Ceutorhynchus species. The kdr mutation in either its heterozygous or homozygous form was found in all investigated Ceutorhynchus species (C. picitarsis, C. pallidactylus, C. napi and C. obstrictus). Samples where pyrethroids in bioassays still provided control at 100% field rate or below contained kdr at frequencies of ≤12.5%, whilst bioassays using 100% field rate that did not control Ceutorhynchus populations contained homozygous resistant individuals at frequencies of greater than 55%. Field sampling demonstrated that kdr frequencies in populations of C. picitarsis and C. obstrictus collected from across France and Germany ranged from 0 to 100%. The present study demonstrated the potential of all four Ceutorhynchus species tested to develop pyrethroid resistance via the L1014F (kdr) mutation. Although kdr frequency varies among species and geographic locations, the risk of loss of pyrethroid insecticide effectiveness is high. Integration of other control tools for resistance management is therefore needed. © 2023 Society of Chemical Industry.

Entomological surveillance on Aedes aegypti during covid 19 period in Cape Coast, Ghana: Risk of arboviral outbreaks, multiple insecticide resistance and distribution of F1534C, V410L and V1016I kdr mutations.

The study assessed the risk of transmission of Aedes-borne arboviruses in a community at Cape Coast during the Covid-19 restriction period in 2020 based on entomological indices. The spatial distribution of insecticide resistance was also assessed in Ae. aegypti population from Cape Coast. Three larval indices were calculated from a household larval survey in 100 randomly selected houses. WHO susceptibility bioassay was performed on female adult Ae. aegypti that were reared from the larvae collected from household containers and other receptacles located outside houses against four insecticides. The mosquitoes were also screened for F1534C, V1016I, and V410L kdr mutations. The estimated larval indices in the study community were House index- 34%, Container index- 22.35%, and Breteau index- 2.02. The mosquito population was resistant to Deltamethrin (0.05%), DDT (4%), Fenitrothion (1%), and Bendiocarb (0.1%). A triple kdr mutation, F1534C, V410L and V1016I were detected in the mosquito population. The study found the risk of an outbreak of Aedes-borne diseases lower in the covid-19 lockdown period than before the pandemic period. The low risk was related to frequent clean-up exercises in the community during the Covid-19 restriction period. Multiple insecticide resistance couple with three kdr mutations detected in the study population could affect the effectiveness of control measures, especially in emergency situations. The study supports sanitation improvement as a tool to control Ae. aegypti and could complement insecticide-based tools in controlling this vector.

Modeling the effect of acquired resistance on cancer therapy outcomes

Adaptive therapy (AT) is an evolution-based treatment strategy that exploits cell–cell competition. Acquired resistance can change the competitive nature of cancer cells in a tumor, impacting AT outcomes. We aimed to determine if adaptive therapy can still be effective with cell’s acquiring resistance. We developed an agent-based model for spatial tumor growth considering three different types of acquired resistance: random genetic mutations during cell division, drug-induced reversible (plastic) phenotypic changes, and drug-induced irreversible phenotypic changes. These three resistance mechanisms lead to different spatial distributions of resistant cells. To quantify the spatial distribution, we propose an extension of Ripley’s K-function, Sampled Ripley’s K-function (SRKF), which calculates the non-randomness of the resistance distribution over the tumor domain. Our model predicts that the emergent spatial distribution of resistance can determine the time to progression under both adaptive and continuous therapy (CT). Notably, a high rate of random genetic mutations leads to quicker progression under AT than CT due to the emergence of many small clumps of resistant cells. Drug-induced phenotypic changes accelerate tumor progression irrespective of the treatment strategy. Low-rate switching to a sensitive state reduces the benefits of AT compared to CT. Furthermore, we also demonstrated that drug-induced resistance necessitates aggressive treatment under CT, regardless of the presence of cancer-associated fibroblasts. However, there is an optimal dose that can most effectively delay tumor relapse under AT by suppressing resistance. In conclusion, this study demonstrates that diverse resistance mechanisms can shape the distribution of resistance and thus determine the efficacy of adaptive therapy.

Fine-scale spatial distribution of deltamethrin resistance and population structure of Anopheles funestus and Anopheles arabiensis populations in Southern Mozambique

BackgroundInsecticide resistance in malaria vectors can be spatially highly heterogeneous, yet population structure analyses frequently find relatively high levels of gene flow among mosquito populations. Few studies have contemporaneously assessed phenotypic, genotypic and population structure analysis on mosquito populations and none at fine geographical scales. In this study, genetic diversity, population structure, and insecticide resistance profiles of Anopheles funestus and Anopheles arabiensis were examined across mosquito populations from and within neighbouring villages.MethodsMosquitoes were collected from 11 towns in southern Mozambique, as well as from different neighbourhoods within the town of Palmeira, during the peak malaria transmission season in 2016. CDC bottle bioassay and PCR assays were performed with Anopheles mosquitoes at each site to determine phenotypic and molecular insecticide resistance profiles, respectively. Microsatellite analysis was conducted on a subsample of mosquitoes to estimate genetic diversity and population structure.ResultsPhenotypic insecticide resistance to deltamethrin was observed in An. funestus sensu stricto (s.s.) throughout the area, though a high level of mortality variation was seen. However, 98% of An. funestus s.s. were CYP6P9a homozygous resistant. An. arabiensis was phenotypically susceptible to deltamethrin and 99% were kdr homozygous susceptible. Both Anopheles species exhibited high allelic richness and heterozygosity. Significant deviations from Hardy–Weinberg equilibrium were observed, and high linkage disequilibrium was seen for An. funestus s.s., supporting population subdivision. However, the FST values were low for both anophelines (− 0.00457 to 0.04213), Nm values were high (9.4–71.8 migrants per generation), AMOVA results showed almost 100% genetic variation among and within individuals, and Structure analysis showed no clustering of An. funestus s.s. and An. arabiensis populations. These results suggest high gene flow among mosquito populations.ConclusionDespite a relatively high level of phenotypic variation in the An. funestus population, molecular analysis shows the population is admixed. These data indicate that CYP6P9a resistance markers do not capture all phenotypic variation in the area, but also that resistance genes of high impact are likely to easily spread in the area. Conversely, other strategies, such as transgenic mosquito release programmes will likely not face challenges in this locality.

Spatial Distribution of Pyrethroid Resistance and kdr Mutations in Aedes aegypti from La Guajira, Colombia.

Dengue, chikungunya, and Zika are of great concern to the public health of Colombia. One of the main control strategies for these diseases is the application of insecticides directed at the Aedes aegypti vector. However, insecticide resistance has been increasingly recorded in the country, making control measures difficult. Here, we evaluated the resistance profiles for pyrethroids in populations of Ae. aegypti from La Guajira, Colombia. The frequency (diagnostic dose, DD) and intensity (2×, 5×, and 10× DD) of resistance to permethrin, deltamethrin, and lambda-cyhalothrin were determined in 15 populations of Ae. aegypti from La Guajira, Colombia, using the bottle bioassay. The kdr mutations V1016I, F1534C, and V410L, were identified, and their allele and genotype frequencies were calculated. Finally, the mortality values for the analyzed pyrethroids were interpolated following the IDW method for predicting pyrethroid resistance. The populations of Ae. aegypti showed a high frequency of resistance to permethrin with a low to moderate intensity, which was associated with the triple-resistant haplotype LL410/II1016/CC1534. They remain susceptible to deltamethrin and, in some populations, expressed the risk of developing resistance to lambda-cyhalothrin.

County-level spatiotemporal distribution of fluoroquinolone-resistant Enterobacteriaceae in outpatient settings of the Veterans' Health Administration, 2000-2017.

Fluoroquinolone resistance among Enterobacteriaceae is a notable challenge for appropriate empiric therapy in outpatient settings. We describe the spatial distribution of fluoroquinolone resistance and its chronological change between 2000 and 2017 in the nationwide Veterans' Health Administration system. We found spatially concentrated increasing prevalence in the 2000s, followed by spatial dispersion in the 2010s.

Three-Dimensional and Threefold Nonlinear Numerical Modeling for Slope-Stabilizing Pile

To enhance the accuracy and reliability of the design calculation for reinforced concrete slope-stabilizing pile, a three-dimensional and threefold nonlinear numerical modeling method was proposed. Namely, in the three-dimensional modeling the material nonlinearity is considered with soil modeled with a nonlinear elastic model, and reinforced concrete pile with an advanced damaged plasticity model for the first time in particular. The boundary nonlinearity is considered by using the Coulomb friction to model the interactions on both soil-pile and soil-rock interfaces. And the geometry nonlinearity is taken into account by adopting the large deformation algorithm. In addition, a post-processing approach for the sectional bending moment of pile body is presented when a reinforced concrete pile is modeled with solid elements, and steel bars with truss elements embedded in concrete. The proposed method was successfully applied to model a pilot pile. The same ultimate bearing capacity as the test was obtained. Comparisons also show that the computed displacements and maximum moments agreed well with the measurements regardless of whether the pile was working in the elastic or damaged plastic state, and even the advent of cracking was identical with the test. In addition, the fluctuation phenomenon of moment diagrams of the pile body in the damaged plastic state as well as the spatial distribution of soil resistance were revealed for the first time. The outcomes highlighted the accuracy, reliability and efficiency of the proposed method.

Spatial distribution of bacterial resistance towards antibiotics of rural sanitation system in China and its potential link with diseases incidence

Chinese government is vigorously promoting toilet renovation in rural areas to reduce the risk of human feces exposure, which would cause infectious diseases, especially antibiotic resistance genes (ARGs) and pathogens. However, the distribution of ARGs in human feces from different regions of China remained ill-defined. It is not yet known how the survival of ARGs after toilet treatment is associated with the regional infection rates. Here, we investigated the prevalence of ARGs in human feces in rural areas of China and their potential relationship with infectious diseases for the first large-scale. The results showed that there were still high ARGs residues in human feces after rural toilet treatment, especially tetM-01 and ermB with average relative abundance as high as 1.21 × 10−1 (Eastern) and 1.56 × 10−1 (Northern), respectively. At a large regional scale, the significant differences in human feces resistomes were mainly shaped by the toilet types, TN, NH3-N, and the bacterial community. A critical finding was that toilets still cannot effectively decrease the pathogenicity risk in human feces. The significant positive relationship (P<0.05) between infectious diseases and ARGs can infer that ARGs in human feces exposure might be a critical path for enhancing the incidence of diseases, as these ARGs hinder the effectiveness of antibiotics.

Estimating the pollutant loss rate based on the concentration process and landscape unit interactions: a case study of the Dianchi Lake Basin, Yunnan Province, China

The landscape analysis model establishes a quantitative relationship between landscape patterns and pollution processes. The spatial heterogeneity within and between landscapes affects the pollutant transmission process and originates from the superposition effect of terrestrial geographical and morphological characteristics. This study aimed to develop a new method to estimate the pollutant loss rate. From the perspective of the flow process of pollutants entering a water body, the interaction between each landscape unit and adjacent unit during pollutant migration was simulated along the pollutant migration flow path. The role of pollutants affected by external forces in the process of migration could be divided into "promoting" and "hindering." Four indices were proposed to simulate the pollutant loads entering the lake. The linear coefficients between the load of the pollutants chemical oxygen demand (CODCr), ammoniacal nitrogen (NH3-N), total nitrogen (TN), and total phosphorus (TP) entering the lake and the pollutant load emission weighted by the upstream and downstream confluence ratio index were 0.930, 0.835, 0.925, and 0.795, respectively, and the non-linear variance explanation coefficients were 87.70%, 87.50%, 87.60%, and 84.70%, respectively. When the surface resistance was integrated into the index as a parameter, the linear and nonlinear correlation coefficients were significantly improved. The linear coefficients were 0.952, 0.897, 0.919, and 0.939, respectively, and the non-linear variance explanations were 99.00%, 97.30%, 95.10%, and 97.30%, respectively. The spatial distribution of landscape surface resistance reflects the spatial movement trend of pollutants from different sources. The indices characterizing the promoting and hindering effects could be integrated to calculate the loss rate of pollutant load entering the lake from landscape units at different locations in the basin space.

Coupled Simulation of Hydrate-Bearing and Overburden Sedimentary Layers to Study Hydrate Dissociation and Methane Leakage

Methane leakage during natural gas hydrate (NGH) exploitation is one of the important challenges restricting its safe development, which necessitates further investigation. However, only a few experimental studies have been conducted to characterize the relationship between methane (CH4) leakage and NGH exploitation. The CH4 leakage mechanism and controlling factors in the hydrate dissociation process are still unclear. A coupled simulator has been developed to study the CH4 hydrate exploitation and the possible leakage of CH4. The new system overcomes the difficulty of constructing hydrate-free overlying strata and seawater in previous studies and can simulate the in situ natural environment containing hydrate reservoirs, overlying strata and overlying seawater as well. In addition, the simulator integrates the spatial distribution of temperature, pressure and electric resistance in hydrate reservoir systems, and allows for the visual monitoring of the overlying strata and the sampling of overburden gas and liquids. The effectiveness of the coupled simulations was verified through experimental testing. The coupled simulations allowed for the characterization of the CH4 leakage mechanism and can be used to develop safe strategies for NGH exploitation.

Deep-Sea Sediment and Water Simulator for Investigation of Methane Seeping and Hydrate Formation

The ubiquitous methane seeping process in the deep-sea environment could significantly influence the global methane cycle and carbon budget. Hydrate formation on the methane bubble during the seeping process is an important way for sequestrating methane during bubble migration. Uncovering the complete methane leakage process needs to reveal the methane leakage pathway and hydrate conversion mechanism. Hence, we built a deep-sea sediment and water simulator to investigate the methane seeping and hydrate formation. The simulator can mimic the deep-sea sediment and water environment with a lower sediment chamber and an upper seawater chamber. The monitoring of the bubble migration path and hydrate transformation and aggregation in the sediment chamber is realized mainly through the spatial distribution of electric resistance and temperature variations. The seawater chamber is equipped with a built-in movable camera and four external windows to observe the rising and morphological evolution of gas and hydrate bubbles. The quantitative storage and escape of CH4 gas could be realized through the measurement of multiple gas/liquid collection ports and cumulative incoming/outgoing gas volume. In addition, a movable biological liquid injection port was designed in the seawater chamber for the coupling CH4 conversion of hydrate formation and microorganism-mediated oxidation. Through the experimental test on each function of the system, the effectiveness of the device was proved. The development of this device has pioneering significance for the experimental simulation of the methane seeping process in a simulated submarine cold spring area.

A PROPOSED METHOD FOR OBTAINING INTER-WELL TRUE RESISTIVITY (R) FROM SEISMIC DATA – A FIELD TRIAL

Information about spatial distribution of rock true resistivity (Rt) throughout an oil or gas field is always desired.

Numerical Simulation, Response Analysis, and Physical Experiment of Induction Logging in an Inclined Fractured Formation

The majority of previous studies of induction logging in fractured formations have typically focused on the variation in spatial resistivity distribution around the wellbore. However, the effect of cumulative charge on the boundaries of an inclined fracture with a distinct morphology on induction logging has rarely been discussed. In this work, the 3-D finite element method (3-D FEM) is adopted to investigate the dual-induction logging response of inclined fractures in formations of different resistivities considering the volume contribution and charge contribution. First, induction logging theory is studied, and a 3-D fractured formation model considering cumulative charges is established. Second, the induction logging responses under various fracture resistivities, apertures, dip angles, and formation resistivities are simulated and analyzed. Subsequently, the corresponding logging response characteristics are studied, and the different response laws of inclined fractures in high- and low-resistivity formations are systematically summarized. Third, a 1:5 miniaturized dual-induction logging instrument was designed and manufactured. Furthermore, two devices were built to measure the induction logging response of the inclined fracture (simulated by nanoscale silver film or metal wire mesh) in low- and high-resistivity formations. The results of the physical experiments are consistent with the numerical results, validating the accuracy of the numerical simulation. Both the results reveal that due to the existence of cumulative charge layers on the upper and lower inclined fracture boundaries, the induction logging response rules of the conductive fractures in high-resistivity formations differ from those in low-resistivity formations, and hence, they should be treated differently.

Spatial distribution of insecticide resistance and susceptibility in Aedes aegypti and Aedes albopictus in India

Spatial distribution of insecticide resistance and susceptibility in Aedes aegypti and Aedes albopictus in India

Structural performance of steel reinforced concrete T-shaped columns exposure to high temperature

This paper mainly focused on the mechanical properties of steel reinforced concrete (SRC) T-shaped columns subjected to axial compression in high temperature. A test program consisting of 8 SRC T-shaped columns was carried out at different influence of specimen parameters. The investigated parameters included axial load ratio, loading eccentricity, loading angle, stirrup spacing and steel ratio. The test results showed that: (1) The failure of axial compression specimens was mainly compression failure. However, the failure of eccentric compression specimens became flexural failure due to the loading eccentricity and loading angle. (2) The fire resistance decreased 50.8% with increasing axial load ratio from 0.2 to 0.6. Decreasing steel ratio from 6.9% to 6.0% led to a decline of 39.4% in the fire resistance. The fire resistance of specimens varied only 1.2% for stirrup spacing from 200 mm to 300 mm. (3) The fire resistance of eccentric compression specimens decreased 8.8%～46.2% compared with the axial compression specimens. The fire resistance of specimens decreased 12.9% with the increase of loading eccentricity from 0 to 40 mm. The fire resistance of specimens decreased 46.2% with the increase of loading angle from 0° to 90°. (4) The influence of axial load ratio and loading angle on the fire resistance was much greater than loading eccentricity. Finally, the fire resistance model of specimens in fire was proposed, and the spatial distribution of fire resistance under the action of two factors was presented, which provided a reference for the post-fire assessment of SRC columns.

Integrated Exploration Model for Concealed Ore Deposit: A Case Study from Shuitou Fluorite Deposit, Inner Mongolia, North China

The demand for fluorite resource is increasing rapidly as most fluorite deposits on Earth’s surface have been exhausted. The newly discovered fluorite deposits in Inner Mongolia are hosted by Permian metamorphosed sandy slate, intermediate-acid intrusive rocks and Cretaceous volcanic sedimentary rocks. The ore bodies are strictly controlled by faults and buried by cover rocks. The feasibility and effectiveness of multi-techniques for prospecting concealed fluorite ore bodies are evaluated, and 10 anomalies are delineated. On the basis of geological features and effectiveness of different methods, the optimum combinations of ore prospecting techniques are proposed for the exploration of zonal type and burial type concealed fluorite ore bodies. Based on comprehensive researches, an integrated exploration model is proposed: (i) select key prospecting targets based on geological backgrounds, regional geochemical anomalies of F and Ca, and remote sensing images; (ii) identify the spatial distribution of low resistivity anomaly and ore-controlling structure from geophysical survey; (iii) evaluate the mineralization potential in fault zone based on F and Ca anomalies in key sections selected from low resistivity anomaly zones; and (iv) evaluate the mineralization potential and reveal the spatial distribution of fluorite ore bodies and ore-controlling faults based on integrated geophysical and geochemical anomalies. The integrated exploration model is verified to be a powerful tool for prospecting concealed fluorite ore bodies in coverage area.