Cogent Geoscience最新文献

Integrated geophysical study of the Subika Gold Deposit in the Sefwi Belt, Ghana 加纳Sefwi带Subika金矿床的综合地球物理研究

Cogent Geoscience Pub Date : 2019-01-01 DOI: 10.1080/23312041.2019.1585406

Kwaku Takyi-Kyeremeh, D. D. Wemegah, K. Preko, A. Menyeh

{"title":"Integrated geophysical study of the Subika Gold Deposit in the Sefwi Belt, Ghana","authors":"Kwaku Takyi-Kyeremeh, D. D. Wemegah, K. Preko, A. Menyeh","doi":"10.1080/23312041.2019.1585406","DOIUrl":"https://doi.org/10.1080/23312041.2019.1585406","url":null,"abstract":"Abstract Geophysical datasets, namely, electrical resistivity, induced polarization, magnetic susceptibility were measured and aeromagnetic interpreted on the Subika concession of Newmont Ghana Gold Limited in order to delineate and model the zone of gold mineralization. The electrical resistivity and induced polarization results delineated the gold mineralized zone as a narrow discrete resistor (>4900 Ωm) and high chargeability (>7.2 ms) zone with a strike length of about 2 km. A strip log plots of 12 diamond drilled core samples showed the zone of mineralization with high alteration and low magnetic susceptibility. Analysis of laboratory magnetic susceptibility measured on selected samples from the pit and selected core samples from the mineralized zones showed a negative correlation between the magnetic susceptibility and gold grades with a correlation coefficient of −0.2 and −0.74, respectively. Similarly, magnetic depth slice produced from the 3D model of the aeromagnetic data depicts the zone of gold mineralization with a low magnetic signature. The zone mineralization was also observed to be striking in the north-east direction. Mineralogical analyses of rock samples revealed alteration processes such as carbonization, sericitization, silicification, chloritization and sulphidation resulting from hydrothermal alteration which accounted for the low magnetic and the magnetic susceptibility signatures of the mineralization zones. The strong resistivity and chargeability response of the mineralized zones are therefore attributed to the silicification and sulphidation alteration, respectively. The results show the effectiveness of applying integrated geophysical, petrophysical as well as mineralogical study in revealing gold mineralization potential of the Subika deposit and the Sefwi belt as a whole.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312041.2019.1585406","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42342731","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Structural controls on groundwater inflow analysis of hardrock TBM 硬质岩石TBM地下水流入的结构控制分析

Cogent Geoscience Pub Date : 2019-01-01 DOI: 10.1080/23312041.2019.1637556

H. Zabidi, A. Rahim, M. Trisugiwo

{"title":"Structural controls on groundwater inflow analysis of hardrock TBM","authors":"H. Zabidi, A. Rahim, M. Trisugiwo","doi":"10.1080/23312041.2019.1637556","DOIUrl":"https://doi.org/10.1080/23312041.2019.1637556","url":null,"abstract":"Abstract Results of analyses on localized jointing system are presented to study the link of groundwater inflow and joint orientations along the 2000 m excavation of Tunnel Boring Machine (TBM-1) site, Karak in conjunction with the construction of Pahang–Selangor Raw Water Transfer Tunnel project. Geology along the tunnel route is predominantly the Main Range Granite Batholith with a lesser extent of metasedimentary rocks of the Karak Formation. Structurally, TBM-1 is dominated by joints oriented at N–S, NW–SE, and NE–SW directions. Strike slip faults that cross-cut the intrusive Main Range Granite rocks trending faults formed the most prominent structures in the vicinity of the Karak. This section of tunnel alignment consists of 2000 meters in length of Ch.8,821.77 m to Ch.10,821.77 m; 456 joints were mapped to create anisotropic conditions of rock section. Eleven significant locations experienced stoppages, thereby affecting the TBM daily progress, and such stoppages were mainly caused by sudden high-pressure groundwater inrushes or wet joint condition. Potential leakage places are identified by three main types of joints orientations. The most permeable tunnel section is in parallel with the main lineament orientation, followed by perpendicular to the tunnel drive direction, and crossing some voids that create pocket water zones.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312041.2019.1637556","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45419660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

GEO-CEOS stage 4 validation of the Satellite Image Automatic Mapper lightweight computer program for ESA Earth observation level 2 product generation - Part 2: Validation. 用于ESA地球观测2级产品生成的卫星图像自动成像仪轻型计算机程序的GEO-CEOS第4阶段验证-第2部分:验证。

Cogent Geoscience Pub Date : 2018-06-11 eCollection Date: 2018-01-01 DOI: 10.1080/23312041.2018.1467254

Andrea Baraldi, Michael Laurence Humber, Dirk Tiede, Stefan Lang

{"title":"GEO-CEOS stage 4 validation of the Satellite Image Automatic Mapper lightweight computer program for ESA Earth observation level 2 product generation - Part 2: Validation.","authors":"Andrea Baraldi, Michael Laurence Humber, Dirk Tiede, Stefan Lang","doi":"10.1080/23312041.2018.1467254","DOIUrl":"https://doi.org/10.1080/23312041.2018.1467254","url":null,"abstract":"ESA defines as Earth Observation (EO) Level 2 information product a multi-spectral (MS) image corrected for atmospheric, adjacency, and topographic effects, stacked with its data-derived scene classification map (SCM), whose legend includes quality layers cloud and cloud-shadow. No ESA EO Level 2 product has ever been systematically generated at the ground segment. To fill the information gap from EO big data to ESA EO Level 2 product in compliance with the GEO-CEOS stage 4 validation (Val) guidelines, an off-the-shelf Satellite Image Automatic Mapper (SIAM) lightweight computer program was selected to be validated by independent means on an annual 30 m resolution Web-Enabled Landsat Data (WELD) image composite time-series of the conterminous U.S. (CONUS) for the years 2006 to 2009. The SIAM core is a prior knowledge-based decision tree for MS reflectance space hyperpolyhedralization into static (non-adaptive to data) color names. For the sake of readability, this paper was split into two. The present Part 2-Validation-accomplishes a GEO-CEOS stage 4 Val of the test SIAM-WELD annual map time-series in comparison with a reference 30 m resolution 16-class USGS National Land Cover Data (NLCD) 2006 map. These test and reference map pairs feature the same spatial resolution and spatial extent, but their legends differ and must be harmonized, in agreement with the previous Part 1 - Theory. Conclusions are that SIAM systematically delivers an ESA EO Level 2 SCM product instantiation whose legend complies with the standard 2-level 4-class FAO Land Cover Classification System (LCCS) Dichotomous Phase (DP) taxonomy.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312041.2018.1467254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36335690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

GEO-CEOS stage 4 validation of the Satellite Image Automatic Mapper lightweight computer program for ESA Earth observation level 2 product generation - Part 1: Theory. 地球观测组织-地球观测卫星委员会用于欧空局地球观测 2 级产品生成的卫星图像自动制图轻量级计算机程序第 4 阶段验证--第 1 部分：理论。

Cogent Geoscience Pub Date : 2018-06-10 eCollection Date: 2018-01-01 DOI: 10.1080/23312041.2018.1467357

Andrea Baraldi, Michael Laurence Humber, Dirk Tiede, Stefan Lang

{"title":"GEO-CEOS stage 4 validation of the Satellite Image Automatic Mapper lightweight computer program for ESA Earth observation level 2 product generation - Part 1: Theory.","authors":"Andrea Baraldi, Michael Laurence Humber, Dirk Tiede, Stefan Lang","doi":"10.1080/23312041.2018.1467357","DOIUrl":"10.1080/23312041.2018.1467357","url":null,"abstract":"ESA defines as Earth Observation (EO) Level 2 information product a single-date multi-spectral (MS) image corrected for atmospheric, adjacency and topographic effects, stacked with its data-derived scene classification map (SCM), whose legend includes quality layers cloud and cloud-shadow. No ESA EO Level 2 product has ever been systematically generated at the ground segment. To fill the information gap from EO big data to ESA EO Level 2 product in compliance with the GEO-CEOS stage 4 validation (Val) guidelines, an off-the-shelf Satellite Image Automatic Mapper (SIAM) lightweight computer program was validated by independent means on an annual 30 m resolution Web-Enabled Landsat Data (WELD) image composite time-series of the conterminous U.S. (CONUS) for the years 2006-2009. The SIAM core is a prior knowledge-based decision tree for MS reflectance space hyperpolyhedralization into static color names. Typically, a vocabulary of MS color names in a MS data (hyper)cube and a dictionary of land cover (LC) class names in the scene-domain do not coincide and must be harmonized (reconciled). The present Part 1-Theory provides the multidisciplinary background of a priori color naming. The subsequent Part 2-Validation accomplishes a GEO-CEOS stage 4 Val of the test SIAM-WELD annual map time-series in comparison with a reference 30 m resolution 16-class USGS National Land Cover Data 2006 map, based on an original protocol for wall-to-wall thematic map quality assessment without sampling, where the test and reference maps feature the same spatial resolution and spatial extent, but whose legends differ and must be harmonized.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6036445/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"36335689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Women in Geoscience: an interview with Claire Parkinson 地球科学中的女性:对克莱尔·帕金森的采访

Cogent Geoscience Pub Date : 2018-01-01 DOI: 10.1080/23312041.2018.1434593

Claire Parkinson

引用次数: 0

Quality of natural waters in carbonate aquifers at a densely populated Odukpani area of cross river state, Southern Nigeria 尼日利亚南部十字河州人口稠密的Odukpani地区碳酸盐含水层天然水的质量

Cogent Geoscience Pub Date : 2018-01-01 DOI: 10.1080/23312041.2018.1463899

O. Igwe, S. I. Ifediegwu, D. Ozoko

{"title":"Quality of natural waters in carbonate aquifers at a densely populated Odukpani area of cross river state, Southern Nigeria","authors":"O. Igwe, S. I. Ifediegwu, D. Ozoko","doi":"10.1080/23312041.2018.1463899","DOIUrl":"https://doi.org/10.1080/23312041.2018.1463899","url":null,"abstract":"Abstract The study area, Odukpani is underlain by cretaceous sediments of the Calabar Flank. The main aquifers are fractured black shales that are inter-bedded with calcareous sandstones. The aquifers range from confined to unconfined. Water samples were taken from boreholes and shallow hand dug wells for chemical characterization with standard laboratory techniques. Results from the chemical analysis show that the waters are mostly alkaline with the exception of two mildly acidic samples. They depicted low electrical conductivity values and a total dissolved solids range from 13.1 to 341 mg/l which indicate fresh water. Cations levels occur in the order, Ca2+ ˃ Na+ ˃ Mg2+ ˃ K+ ˃ Fe2+ while anions occur as the following order, HCO3− ˃ SO42− ˃ Cl− ˃ CO3− ˃ NO3−. Piper trilinear and stiff plots show that Ca2+ – Na+ – HCO3− is dominant water type. The waters are supersaturated with respect to calcite in five of the samples. The rest have calcite under-saturation. Areas of calcite super-saturations are likely undergoing precipitation of carbonate minerals in the aquifer matrices. Precipitation and dissolution of carbonate minerals within the aquifers are likely contributing to the modification of flow characteristics of the aquifer. Comparison of the water chemistry with standards set by regulatory bodies indicates that the waters are of good quality.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312041.2018.1463899","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44084018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Advantages of unmanned aerial vehicle (UAV) photogrammetry for landscape analysis compared with satellite data: A case study of postmining sites in Indonesia 无人机(UAV)摄影测量在景观分析中的优势与卫星数据的比较——以印度尼西亚采矿后场地为例

Cogent Geoscience Pub Date : 2018-01-01 DOI: 10.1080/23312041.2018.1498180

K. Iizuka, Masayuki Itoh, S. Shiodera, T. Matsubara, Mark Dohar, Kazuo Watanabe

{"title":"Advantages of unmanned aerial vehicle (UAV) photogrammetry for landscape analysis compared with satellite data: A case study of postmining sites in Indonesia","authors":"K. Iizuka, Masayuki Itoh, S. Shiodera, T. Matsubara, Mark Dohar, Kazuo Watanabe","doi":"10.1080/23312041.2018.1498180","DOIUrl":"https://doi.org/10.1080/23312041.2018.1498180","url":null,"abstract":"Abstract This study presents the advantages of detailed landscape analysis by UAV (drone hereafter) photogrammetry compared with satellite remote sensing data. First, satellite data are used for generating a coarse-scale land use/land-cover (LULC) map of the study region using conventional GIS techniques. The Advanced Land Observation Satellite-2 (ALOS-2) Phased Array L-band Synthetic Aperture Radar-2 (PALSAR-2) L-Band backscattering data are processed with a multilayer perceptron (MLP) supervised classification for generating a categorical map. The satellite-derived classification map resulted in eight general land-cover types with a ground resolution of 7.5 m, providing a moderate-resolution representation of the island landscapes. Second, the drone’s image data are used to collect ground survey information and microscale information of the local site by implementing a structure from motion (SfM) technique to develop mosaicked orthorectified images of the sites. The orthophoto and digital surface model (DSM) derived from the drone-based data had resolutions of 0.05 m and 0.1 m, respectively. The SAR-based LULC map showed an overall accuracy of 78.1%, and the drone-based LULC map had an overall average accuracy of 92.3%. The subset area of the SAR map was compared with the drone-based map and showed average Kappa statistics of 0.375, demonstrating that satellite data cause challenges in correctly delineating the local land environment. The terrain information generated by the SfM method provided a good representation of the topography showing the drastic changes in the environment. The results indicate the usefulness of drone-based landscape analysis for future land-use planning at a local village scale.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312041.2018.1498180","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46490134","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 40

The use of terrestrial laser scanning in monitoring and analyses of erosion phenomena in natural and anthropogenically transformed areas 利用地面激光扫描监测和分析自然和人为改造地区的侵蚀现象

Cogent Geoscience Pub Date : 2018-01-01 DOI: 10.1080/23312041.2018.1437684

P. Dąbek, Ciechosław Patrzałek, B. Ćmielewski, R. Żmuda

{"title":"The use of terrestrial laser scanning in monitoring and analyses of erosion phenomena in natural and anthropogenically transformed areas","authors":"P. Dąbek, Ciechosław Patrzałek, B. Ćmielewski, R. Żmuda","doi":"10.1080/23312041.2018.1437684","DOIUrl":"https://doi.org/10.1080/23312041.2018.1437684","url":null,"abstract":"Abstract Implementation of terrestrial laser scanning creates new opportunities in the analysis of processes occurring in the environment. Terrestrial laser scanning (TLS) enables fast, precise mapping of land relief and dimensions of technical structures. TLS allows moving from traditional methods, such as point measurement, to differential analyses of a relief model. TLS allows accurate analyses of land relief changes and erosion phenomena, both in terms of the processes intensity and range, and the initial and intensifying events. The paper presents the authors’ experiment with the use of the TLS technology in erosion processes monitoring and analyses. The authors present the methodology of using TLS which contributed to the acquisition of reliable results by providing optimal conditions for the research. The paper shows the effects of laser scanning in order to analyse the intensity of soil erosion in mountainous forest area with a large number of measurement stations, which resulted in a dense points cloud. Differential model method allowed to evaluate erosion phenomena in the form of rills resulting from surface flushing, which is impossible to assess by traditional methods of erosion measurements. In the paper, we showed the necessity to choose the proper coordinate system (object or scanner) for the analysis of the landslide, depending on structure and direction of the soil masses movement. The application of the object coordinate system showed greater erosion phenomena range (ca 12%) on buttress stabilizing landslide and ca 44% on natural landslide, in which the application of the object coordinate system increases the number of observations by 40%.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312041.2018.1437684","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42266557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Determination of basalt zones using basalt extraction index (BEI) and ASTER image classification 使用玄武岩提取指数（BEI）和ASTER图像分类确定玄武岩带

Cogent Geoscience Pub Date : 2018-01-01 DOI: 10.1080/23312041.2018.1466672

M. Argany, A. Ramezani, A. Ahmadi

{"title":"Determination of basalt zones using basalt extraction index (BEI) and ASTER image classification","authors":"M. Argany, A. Ramezani, A. Ahmadi","doi":"10.1080/23312041.2018.1466672","DOIUrl":"https://doi.org/10.1080/23312041.2018.1466672","url":null,"abstract":"Abstract One of the most important applications of remote sensing is presented in mining and exploration of mineral deposits and evaluation of prospective targets. This project discusses how to use remote sensing knowledge in order to make classification and separation of surface rocks in the Dir-o-Morreh mine. The main purpose of this research is to identify the areas containing high-quality basalt. In this regard, we utilize ASTER multi-spectral satellite imagery, which has relatively good spectral and spatial resolution. At the first step, in order to achieve the correct spectral composition of the basalt spectrum, the spectral signature of basalt stone, defined by Johns Hopkins University, was used. Afterward, the basalt extraction index (BEI) was defined regarding the behavior of the ASTER satellite image bands as well as the initial data provided by the owners of the intended study area. Then, the Convolution and Morphology filter was applied over the images to extract high-quality basalt using an appropriate color composition of the images. At the next step, in order to have better visualization, different maps containing different classes were created using the Maximum Likelihood algorithm. Finally, two indices were developed regarding all research data and field investigations in order to extract basalt zones. The first index discovers basalt zones in the study area, and the second one classifies high-quality basalt and altered basalt zones.","PeriodicalId":42883,"journal":{"name":"Cogent Geoscience","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/23312041.2018.1466672","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49450328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Women in Geoscience: An interview with Ellen Kooijman 地球科学中的女性:对Ellen Kooijman的采访

Cogent Geoscience Pub Date : 2018-01-01 DOI: 10.1080/23312041.2018.1432282

E. Kooijman

引用次数: 0