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2019

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Articles 601 - 630 of 1657

Full-Text Articles in Earth Sciences

Study On Uniaxial Compression Mechanical Properties Of Sandstone With Different Moisture Content And Wave Velocity Method, Duan Tianzhu, Ren Yaping Aug 2019

Study On Uniaxial Compression Mechanical Properties Of Sandstone With Different Moisture Content And Wave Velocity Method, Duan Tianzhu, Ren Yaping

Coal Geology & Exploration

In order to investigate the mechanical properties and damage of sandstone under different uniaxial compression, the static uniaxial compression tests of five sandstones with different moisture content were carried out, and the physical and mechanical parameters were obtained. And the wave velocity of the sandstone samples with different moisture content were measured by ultrasonic detector. Then the sandstone was loaded to 80% peak intensity and then unloaded to 0. The acoustic wave velocity of sandstone was measured at this time. The damage was determined by acoustic wave method. The results show that the peak strength of sandstone under uniaxial compression …

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A Method Of Random Noise Suppression Based On Compressed Sensing, Yang Liangang, Li Lingyun, Yang Yumei, Qu Yuanji, Yan Ke Aug 2019

A Method Of Random Noise Suppression Based On Compressed Sensing, Yang Liangang, Li Lingyun, Yang Yumei, Qu Yuanji, Yan Ke

Coal Geology & Exploration

With the development of high precision seismic exploration technology, the use of high fidelity methods to improve the SNR of seismic data becomes the key to denoising. Curvelet threshold method can effectively suppress random noise, but at the same time the method is easy to produce pseudo Gibbs shock phenomenon, resulting in local distortion of the signal, thus affecting the processing effect. To solve this problem, a method of seismic signal denoising based on compressing sensing(CS) is presented in this paper. The method uses the difference between sparse representation of random noise and effective signal in curvelet sparse domain to …

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Channel Wave Advanced Detection Method Based On Kirchhoff Migration And Its Application, Zhao Yunpei, Wang Wei, Hou Xianhua Aug 2019

Channel Wave Advanced Detection Method Based On Kirchhoff Migration And Its Application, Zhao Yunpei, Wang Wei, Hou Xianhua

Coal Geology & Exploration

In order to detect the geological structures in the front of the working face 1199 in Gequan mine of Xingtai mining area, underground channel wave seismic exploration was used to conduct advanced detection, linear Radon transform was used to extract the reflection wave from the front of the roadway, parameter information of the surrounding rocks were obtained through velocity analysis in time domain, The abnormal geological bodies in the front of the roadway were imaged through Kirchhoff migration. The results indicated that there existed anomalies at 205 m and 237 m away from the geophone point G12 in the front …

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Shale Gas Potential Of Yanguanjie Formation And Longtan Formation In Central And Southeastern Hunan Province, Cao Taotao, Deng Mo, Liu Hu, Huang Yanran, Stefan Andrew Hurssthouse Aug 2019

Shale Gas Potential Of Yanguanjie Formation And Longtan Formation In Central And Southeastern Hunan Province, Cao Taotao, Deng Mo, Liu Hu, Huang Yanran, Stefan Andrew Hurssthouse

Coal Geology & Exploration

In order to reveal the shale gas potential and exploration direction of the marine-continental transitional shale in central and southeastern Hunan, samples were collected from the Lower Carboniferous Yanguanjie Formation and Upper Permian Longtan Formation, measurements were conducted on TOC, Rran, kerogen carbon isotope, maceral composition, X-ray diffraction, scanning electron microscopy, porosity, permeability and methane sorption capacity. The results indicate that Yanguanjie Formation and Longtan Formation shale are at the mature stage, and mainly dominated by type Ⅲ kerogen. The Longtan shale generally has higher TOC content, while Yanguanjie shale has usually low TOC content. The minerals are …

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Management Of National Planned Coal Mining Areas And Discrimination With Coal Mining Areas, Wang Xiangsheng, Wang Meng, Liu Jingchun Aug 2019

Management Of National Planned Coal Mining Areas And Discrimination With Coal Mining Areas, Wang Xiangsheng, Wang Meng, Liu Jingchun

Coal Geology & Exploration

In view of the confusion between national planned coal mining areas and coal mining areas, based on the relevant standards and notices, the definitions of national planned coal mining areas and coal mining areas are interpreted in detail. This paper introduces the basic situation of the first and second batches of national planned coal mining areas and the《National Mineral Resources Planning (2016-2020)》. The differences between the two are expounded in detail from the aspects of delineation purpose, delimitation basis and formation period. It is pointed out that the competent department of national planned coal mining areas is the Ministry of …

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Research And Application Of Cbm Surface Extraction Based On Coal Mine With “Gas Drainage First, Construction Later” And Resource Development, Wang Jing, Yao Tuanqi, Cheng Bin Aug 2019

Research And Application Of Cbm Surface Extraction Based On Coal Mine With “Gas Drainage First, Construction Later” And Resource Development, Wang Jing, Yao Tuanqi, Cheng Bin

Coal Geology & Exploration

Aiming at the safety index put forward by "gas drainage first, construction later" of coal mine at present and the resource characteristics of many coal seams in northern Guizhou Province, and at the same time making up for the lack of systematization and large blind area of surface gas drainage deployment at present, this paper took Duijiangnan coal mine as an example to carry out the research of coal bed methane surface drainage deployment. Based on the complex topographic conditions, coal seam development characteristic(multiple layers, thin thickness, group distribution), coal body structure, development and deployment requirements in this area, the …

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Influencing Factors Of Surface Gas Extraction Effect In Wangpo Minefield Of Jincheng Mining Area, Du Zhiqiang Aug 2019

Influencing Factors Of Surface Gas Extraction Effect In Wangpo Minefield Of Jincheng Mining Area, Du Zhiqiang

Coal Geology & Exploration

The effect of surface gas extraction in Wangpo minefield of Jincheng mining area is poor. In order to find out the causes and to guide the construction of future surface gas extraction, the occurrence conditions of CBM resources in the study area were analyzed and compared with those of adjacent Chengzhuang minefield where the extraction effect is good, the quality of the produced water was tested, at the same time the fracture forms were observed underground. The comprehensive analysis indicated that the abundance of coal gas resources and the reservoir conditions were the major intrinsic basic factors influencing the gas …

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Coal Control Factors Of Middle Jurassic Shimengou Formation In Beidatan Area, East Part Of The Northern Qaidam Basin, Peng Minghong, Tian Jingchun, Zhang Xiang, Chen Lei, Zeng Jianqiang, Wang Suying Aug 2019

Coal Control Factors Of Middle Jurassic Shimengou Formation In Beidatan Area, East Part Of The Northern Qaidam Basin, Peng Minghong, Tian Jingchun, Zhang Xiang, Chen Lei, Zeng Jianqiang, Wang Suying

Coal Geology & Exploration

The key of the coal exploration in Beidatan area of Qinghai Province is the coal accumulation environment in the sedimentary period and the control of coal seam occurrence by tectonic action before and after sedimentation. To identify Shimengou Formation coal controlling factors in Beidatan area, east part of the northern Qaidam basin, effectively guide the coal exploration of the coal bearing area, through field outcrops, drilling, geophysical prospecting and other geological information system, based on the analysis of coal accumulating environment and structural function of Shimengou Formation in Beidatan area, the control factors of coal were deeply discussed from coal …

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Table Of Contents, The Editors Aug 2019

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

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Technology And Application Of Indirect Fracturing In Cbm Vertical Well Of Broken And Soft Coal Seam With Low Permeability, Zhou Jiajia Aug 2019

Technology And Application Of Indirect Fracturing In Cbm Vertical Well Of Broken And Soft Coal Seam With Low Permeability, Zhou Jiajia

Coal Geology & Exploration

In order to solve the problems of pulverized coal output and fracturing fracture not easy to extend during fracturing operation in the broken and soft coal seam with low permeability, the adaptability and fracturing fracture distribution of CBM during indirect fracturing are studied by means of in-situ stress and numerical simulation, and the engineering practice of indirect fracturing has been tested in Hongshandian mining area of Hunan Province. The results show that indirect fracturing can effectively improve the fracturing effect of the broken and soft coal seam with low permeability, and increase the fracture length. When the roof and floor …

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Coalbed Methane Migration Mechanism Under Adsorption-Desorption Condition In Coal, Liu Yongqian, Zhang Shulin, Shu Longyong Aug 2019

Coalbed Methane Migration Mechanism Under Adsorption-Desorption Condition In Coal, Liu Yongqian, Zhang Shulin, Shu Longyong

Coal Geology & Exploration

The migration law of coalbed methane(CBM) with adsorption has always been the focus of attention in the field of coalbed methane geology. In order to study the mechanism of CBM migration under adsorption-desorption state, the deduction of gas adsorption-desorption equation and theoretical analysis of gas diffusion-seepage in porous media were carried out, and new viewpoints were put forward by means of experimental analysis of CBM migration. The results identified that:(1) for the CBM migration, pore structure of coal body has the storage-resistance effect, the dual functions of gas storage and gas pressure drop form the basic feature of coal matrix, …

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Occurrence Of Antimony In Magmatic Intrusive Coal Seam: A Case Study From The Wolonghu Coal Mine, Huaibei Coalfield, China, Ou Jinping, Zheng Liugen, Wei Xiangping, Liu Sikui, Li Liyuan, Liu Meng, Huang Xiaoyu Aug 2019

Occurrence Of Antimony In Magmatic Intrusive Coal Seam: A Case Study From The Wolonghu Coal Mine, Huaibei Coalfield, China, Ou Jinping, Zheng Liugen, Wei Xiangping, Liu Sikui, Li Liyuan, Liu Meng, Huang Xiaoyu

Coal Geology & Exploration

In order to investigate the influence of magmatic alteration on the occurrence characteristics of antimony in coal seam, 12 samples of magmatic magma and coal were collected from Wolonghu coal mine in Huaibei coalfield, Anhui Province, and the content of Sb was determined by atomic fluorescence spectrometry(AFS). The coal quality parameters are analyzed. The results are as follows:the coal in Wolonghu magmatic intrusion area has the characteristics of ultra-low volatile matter, medium ash content and ultra-low sulfur content. And the main forms of sulfur in coal are organic sulfur and pyrite sulfur. Under the influence of magmatic hydrothermal solution, ash …

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Analysis Of Reservoir Conditions Of Shale Gas In Middle Permian Wenbishan Formation In Fujian Province, Chen Quanlin Aug 2019

Analysis Of Reservoir Conditions Of Shale Gas In Middle Permian Wenbishan Formation In Fujian Province, Chen Quanlin

Coal Geology & Exploration

This study is performed on the geological conditions of shale gas in Middle Permian Wenbishan Formation in Fujian Province. It is based on organic geochemistry, rock minerals and reservoir physical property after geology survey and drilling. The results indicate that kerogen is Ⅲ-type, organic carbon is usually between 1% to 2%, Rran is between 3.76% to 4.91% in the shale of Wenbishan Formation, and the shale is in the mature stage. The content of brittle minerals is generally low. The shale has medium porosity and extremely low permeability, the micro and meso-pores constitute the major space for gas adsorption. …

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Water Inflow Law Of The First Working Face Based On Water Pre-Draining From Roof, Li Yongtao, Yang Jian Aug 2019

Water Inflow Law Of The First Working Face Based On Water Pre-Draining From Roof, Li Yongtao, Yang Jian

Coal Geology & Exploration

In order to establish water control technology system in Inner Mongolia-Shaanxi contiguous area, we carried out some researches(e.g. overburden failure law, hydrogeological conditions, prediction of water inflow and pre-drainage of roof water) in Nalinhe No.2 coal mine. The results showed that three methods(i.e. coring, drilling fluid leakage observation and borehole color TV detection) were used to explore water-conducting fracture zone(103.23 m), and the ratio of the height of the fractured zone to the mining height was 18.8. Water-conducting fracture zone could connect three aquifers, and the Zhiluo Formation bottom aquifer was the main aquifer threatening safety mining. Water inflow and …

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Microseismic Test And Numerical Simulation Analysis Of Floor Failure Depth Of Isolated Coal Mining Face, Zhao Chunhu Aug 2019

Microseismic Test And Numerical Simulation Analysis Of Floor Failure Depth Of Isolated Coal Mining Face, Zhao Chunhu

Coal Geology & Exploration

Aiming at the damage of coal seam floor caused by mining in isolated coal mining face, taking 11913 isolated coal mining face in Gequan coal mine of Hebei Province as the research object, and using KJ959 coal mine microseismic monitoring system to detect the floor failure depth. It is recognized that the microseismic events mainly occur in the roadway of the isolated coal mining face during the mining process, and the maximum vertical failure depth is about 20~25m; Moreover, using the COMSOL multi-physical field numerical simulation platform, the variation of in-situ stress and failure law of coal seam floor under …

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Modification Function Of Magnetic Treatment On Grouting Clay Slurry, Xue Weifeng, Wang Sujian, Deng Zengshe, Huang Kejun, Han Lei, Ji Ruijun, Liang Shaojian Aug 2019

Modification Function Of Magnetic Treatment On Grouting Clay Slurry, Xue Weifeng, Wang Sujian, Deng Zengshe, Huang Kejun, Han Lei, Ji Ruijun, Liang Shaojian

Coal Geology & Exploration

Clay slurry was treated through magnetization. The characteristics of the physical property change of the clay slurry after magnetic treatment such as viscosity, density, pH value, conductivity, syneresis rate, concretion rate and anti-permeability were studied. After magnetic treatment, density, viscosity and syneresis rate of the clay slurry decrease, pH, conductivity and concretion rate increase, the syneresis rate and the concretion rate are improved with the magnetization time. The magnetic treatment improves the rheological property of clay slurry, the anti-permeability performance of the cemented body of clay slurry after magnetic treatment rises greatly compared to the cemented body of clay slurry …

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Inversion Analysis Of Earth Pressure For Limited Soil Between Oblique Support Retaining Foundation Pit And Adjacent Basement, Zhang Guomao, Peng Wenxiang Aug 2019

Inversion Analysis Of Earth Pressure For Limited Soil Between Oblique Support Retaining Foundation Pit And Adjacent Basement, Zhang Guomao, Peng Wenxiang

Coal Geology & Exploration

In order to study the distribution of earth pressure for limited soil between oblique support retaining foundation pit and adjacent basement, back analysis of site monitoring data of a foundation pit was studied. Based on the improved cubic spline method of the trial algorithm, Matlab software was used to calculate the bending moment value of the supporting structure and the earth pressure value behind the pile. The results show the earth pressure of limited soil is influenced by displacement mode, non-limit state and boundary conditions. The active earth pressure of limited soil above the excavation surface shows a distinct "R" …

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Numerical Simulation On Mechanism Of Thrust Fault Reactivation During Mining, Min Feihu, Xiang Biwei, Liu Hui, Zhu Xiaojun Aug 2019

Numerical Simulation On Mechanism Of Thrust Fault Reactivation During Mining, Min Feihu, Xiang Biwei, Liu Hui, Zhu Xiaojun

Coal Geology & Exploration

It is a hot issue in mine disaster research about the activation of faults during the process of coal mining and excavation. In order to reveal the influence of coal mining on fault activation under different fault dip conditions, Xinji No.2 mine in Huainan coalfield was taken as an example, and numerical simulation with FLAC3D was used to systematically study the dynamic activation law of thrust faults during mining beside the faults, and to clarify the relationship among fault activation position and fault dip angle and excavated distance of working face. The results show that the fault activation is …

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Application Of Seismic Exploration Technology In Forecasting Unconventional Gas Enrichment Area Of Coal Measures, Wang Shuwei Aug 2019

Application Of Seismic Exploration Technology In Forecasting Unconventional Gas Enrichment Area Of Coal Measures, Wang Shuwei

Coal Geology & Exploration

For forecasting unconventional gas enrichment area in coal measures of eastern Ordos basin, seismic exploration was used to forecast the gas in this new field. First of all, it took the post-stack impedance inversion to forecast the lithology of the reservoir, it can get the number of sample points from the impedance threshold, and get the thickness of time by cal-culating the sampling rate, after that it can get the strata thickness by multiplying the thickness of time and the velocities of strata; second, it took the pre-stack AVO inversion to forecast the lithology gas-bearing properties of the reservoir, based …

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Constrained Inversion Method And Application Effect Of Tem Data Of Fixed Source Loop Device, Hou Yanwei, Yao Weihua Aug 2019

Constrained Inversion Method And Application Effect Of Tem Data Of Fixed Source Loop Device, Hou Yanwei, Yao Weihua

Coal Geology & Exploration

In order to eliminate the obvious framing effect after the TEM fixed source loop device increases the receiving area, to improve the delamination ability of TEM to enhance the fine resolution for different electrical strata, the regularization inversion method with constraint is adopted. In the inversion algorithm, the Lagrange factor is adjusted adaptively by CMD regularization factor. In order to ensure the efficiency, stability and convergence of the results of the inversion process, the thickness of each layer of the inversion model is discretized according to the equal logarithmic interval, and the ill conditioned property of the matrix equation is …

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Experimental Study And Economic Evaluation Of Low Temperature Drying Treatment Of Abandoned Water-Based Drilling Fluid, Li Zhijun, Liu Xusan, Wang Bo, Zhao Wei Aug 2019

Experimental Study And Economic Evaluation Of Low Temperature Drying Treatment Of Abandoned Water-Based Drilling Fluid, Li Zhijun, Liu Xusan, Wang Bo, Zhao Wei

Coal Geology & Exploration

Abandoned water-based drilling fluids are the waste of oil drilling engineering operations. It will not only keep the cost of drilling fluid high, but also have a very adverse impact on the environment if it is directly discharged. Reusing of abandoned water-based drilling fluid after low-temperature drying treatment is one of treatment methods which is economic and conforms to the modern development trend. In this paper, the experimental study and economic evaluation of the low-temperature drying technology of polymer drilling fluid system, sulfonated drilling fluid system and Sichuan shale gas well drilling fluid system were conducted. The results show that …

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Instability Mechanism And Anti-Sloughing Drilling Fluid Technique For Deep Coal Seam Of Tarim Basin, Li Heng, He Shiming, Tang Ming, Li Ning, Yang Pei, Zhang Zhen Aug 2019

Instability Mechanism And Anti-Sloughing Drilling Fluid Technique For Deep Coal Seam Of Tarim Basin, Li Heng, He Shiming, Tang Ming, Li Ning, Yang Pei, Zhang Zhen

Coal Geology & Exploration

In view of the complicated problems of drilling fluid leakage and hole collapse during the drilling of deep coalbed in Tarim basin, the microstructure and physical and chemical properties of coal were tested by vitrinite reflectance analysis, X ray diffraction and scanning electron microscope, and the mechanism of coal seam instability was confirmed. The fixed carbon content of the coal exceeds 60%, the vitrinite reflectance is greater than 1.1%, and coal have high degree of coalification, is brittle and easy to break. The total amount of clay mineral is less than 25%, and there is no strong water-sensitive mineral montmorillonite …

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Study On Slope Stability And The Effect Of Highfill On The Mechanical Properties Of Red Clay Foundation, Gao Shengxiang, Xu Qiang, Ma Hongyu, Wu Shenglin, Wu Kang, Liu Peng, Wu Zehui Aug 2019

Study On Slope Stability And The Effect Of Highfill On The Mechanical Properties Of Red Clay Foundation, Gao Shengxiang, Xu Qiang, Ma Hongyu, Wu Shenglin, Wu Kang, Liu Peng, Wu Zehui

Coal Geology & Exploration

This paper takes a highfill slope in Anning in Yunnan Province as a case, using investigation, monitoring and other methods, on the basis of the distribution characteristics of red clay, the physical and mechanical properties of red clay before and after filling were analyzed, then the stability of slope was studied by numerical simulation software. The results show that the physical and mechanical indexes of the red clay foundation decrease first and then increase before and after the fill project, the stability of the fill slope shows the trend of decrease first and then increase. The ground fissures in the …

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A Pipeline Robot Detection Image Enhancement Method Based On Image Fusion And Improved Threshold, Yuan Mingdao, Tan Cai, Li Yang, Xu Yunqian, Zhang Xuhui, Yang Jingxue Aug 2019

A Pipeline Robot Detection Image Enhancement Method Based On Image Fusion And Improved Threshold, Yuan Mingdao, Tan Cai, Li Yang, Xu Yunqian, Zhang Xuhui, Yang Jingxue

Coal Geology & Exploration

Pipeline robot detection technology can quickly, accurately and intuitively identify the structure and hidden functional troubles of pipeline. However, due to the restriction of the pipeline environment, the detected images have problems such as uneven illumination, low contrast and blurred details. Therefore, an enhancement technique for detected image of pipeline robot is proposed. First, the contrast limited adaptive histogram equalization(CLAHE) and homomorphic filtrate(HF) are applied to deal with the problem of uneven illumination and low contrast, and the result images of the two methods are fused. Secondly, the fusion images are transformed by the Nonsubsampled Contourlet Transform(NSCT), and the improved …

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Detection Accuracy Analysis Of Tsp And Its Application In A River-Crossing Tunnel Construction, Li Junjie, Zhang Honggang, He Jianshe, Rong Xin, Li Jianqiang, Guo Jiahao Aug 2019

Detection Accuracy Analysis Of Tsp And Its Application In A River-Crossing Tunnel Construction, Li Junjie, Zhang Honggang, He Jianshe, Rong Xin, Li Jianqiang, Guo Jiahao

Coal Geology & Exploration

Aiming at the problems of TSP such as long detection time and strong experience-depending, in order to improve the accuracy and the efficiency of TSP detection, we analyzed the key factors which affect data acquisition and processing accuracy of TSP and summarized the experiences of improving the detection efficiency of TSP. In combination with the TSP advanced geological prediction work in a river-crossing tunnel for water distribution project in Qiandaohu lake, the TSP tracing prediction or GPR detection in the area where the TSP resolution decreases were carried out and the geophysical abnormal area was verified by drilling. The results …

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Innovations In (U–Th)/He, Fission Track, And Trapped Charge Thermochronometry With Applications To Earthquakes, Weathering, Surface‐Mantle Connections, And The Growth And Decay Of Mountains, Alexis K. Ault, Cécile Gautheron, Georgina E. King Aug 2019

Innovations In (U–Th)/He, Fission Track, And Trapped Charge Thermochronometry With Applications To Earthquakes, Weathering, Surface‐Mantle Connections, And The Growth And Decay Of Mountains, Alexis K. Ault, Cécile Gautheron, Georgina E. King

Geosciences Faculty Publications

A transformative advance in Earth science is the development of low‐temperature thermochronometry to date Earth surface processes or quantify the thermal evolution of rocks through time. Grand challenges and new directions in low‐temperature thermochronometry involve pushing the boundaries of these techniques to decipher thermal histories operative over seconds to hundreds of millions of years, in recent or deep geologic time and from the perspective of atoms to mountain belts. Here we highlight innovation in bedrock and detrital fission track, (U–Th)/He, and trapped charge thermochronometry, as well as thermal history modeling that enable fresh perspectives on Earth science problems. These developments …

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Multi-Phased Hypogene Speleogenesis In A Marginal Horst Structure Of The Malé Karpaty Mountains, Slovakia, Pavel Bella, Pavel Bosák, Petr Mikysek, Juraj Littva, Helena Hercman, Jacek Pawlak Aug 2019

Multi-Phased Hypogene Speleogenesis In A Marginal Horst Structure Of The Malé Karpaty Mountains, Slovakia, Pavel Bella, Pavel Bosák, Petr Mikysek, Juraj Littva, Helena Hercman, Jacek Pawlak

International Journal of Speleology

The Plavecká jaskyňa Cave on the western fault edge of the Malé Karpaty Mountains (western Slovakia) is a result of multi-phased hypogene speleogenesis. It formed in fractured Triassic carbonates by waters ascending along the Vienna Basin Transform Fault between Malé Karpaty Mountains and Záhorská nížina Lowland (the north-eastern part of the Vienna Basin) and/or the N–S-trending faults that intersect it in the cave vicinity. Morphologically, the cave is featured by (1) phreatic chimneys, cupolas, ceiling pockets, enlarged fissures with spongework cavities, upward wall channels and upward oriented large scallops, (2) epiphreatic flat corrosion bedrock floors, feeding fissures and wall water-table …

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Small Soil C Cycle Responses To Three Years Of Cover Crops In Maize Cropping Systems, Anna M. Cates, Matthew D. Ruark, A. Stuart Grandy, Randall D. Jackson Aug 2019

Small Soil C Cycle Responses To Three Years Of Cover Crops In Maize Cropping Systems, Anna M. Cates, Matthew D. Ruark, A. Stuart Grandy, Randall D. Jackson

Faculty Publications

Cover crops are touted for their ability to improve many ecosystem functions in annual cropping systems. In addition to water and nutrient retention, cover crops may influence C cycling by increasing total C inputs to the agroecosystem, stimulating microbial populations, altering main crop residue decomposition rate, or changing litter chemistry over time. We assessed whether annual (rye) or perennial (bluegrass) cover crops in maize cropping systems influenced maize residue decomposition (litterbags) or microbial communities (shotgun metagenomics) in soil and litter, and whether these cover crops had an effect on microbially active pools of C: particulate organic matter (POM) C and …

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Modeling Surface Roughness As An Indicator Of Age And Landslide Susceptibility, And The Spatial Inventory Of Prehistoric Landslides: Green River Valley, Washington, Rebecca Naomi Garriss Aug 2019

Modeling Surface Roughness As An Indicator Of Age And Landslide Susceptibility, And The Spatial Inventory Of Prehistoric Landslides: Green River Valley, Washington, Rebecca Naomi Garriss

Dissertations and Theses

Developing detailed landslide inventory maps of prehistoric landslides is essential to interpret the frequency and conditions under which slopes have failed. When coupled with age estimates, landslide inventories can yield better predictions for future slope failures, thereby improving hazard assessments and increasing chances for mitigation. Developing proxies for landslide age is an important area of research, but age dating prehistoric landslides can be challenging due to sparse datable organic material within landslide deposits, and to time or access constraints. In this thesis, surface roughness of the landslide deposit is used to construct a best-fit age-roughness model that quantitatively assigns age …

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Machine Learning Predicts Aperiodic Laboratory Earthquakes, Olha Tanyuk, Daniel Davieau, Charles South, Daniel W. Engels Aug 2019

Machine Learning Predicts Aperiodic Laboratory Earthquakes, Olha Tanyuk, Daniel Davieau, Charles South, Daniel W. Engels

SMU Data Science Review

In this paper we find a pattern of aperiodic seismic signals that precede earthquakes at any time in a laboratory earthquake’s cycle using a small window of time. We use a data set that comes from a classic laboratory experiment having several stick-slip displacements (earthquakes), a type of experiment which has been studied as a simulation of seismologic faults for decades. This data exhibits similar behavior to natural earthquakes, so the same approach may work in predicting the timing of them. Here we show that by applying random forest machine learning technique to the acoustic signal emitted by a laboratory …

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