An analysis of joint patterns were carried out on multiple exposures in Albian to Turonian strata belonging to the Abakaliki Formation (Asu River Group) and the Eze-Aku Formation (Eze-Aku Group) on the eastern flank of the Abakaliki Anticlinorium of the Southern Benue Trough. The analysis was carried out using FracPaQ a MATLAB based toolbox for quantification of fracture patterns. The tool was used to calculate fracture density, and intensity of the traces; to quantify scaling distributions, and to determine dilation tendencies, slip tendencies, and to quantify connectivity, and fluid flow directions. Analysis show the presence of two major joint systems: A Major Cross-Fold Joint (CF-J) system -orthogonal to the regional fold axes- consisting of the CF-J1 set trending NW/SE (315±5°), and a subordinate Longitudinal Joint System (L-J) -subparallel to the fold axes- consisting of a NE-SW L-j1 set, an ENE-WSW (60°±5°) L-j2 set, and an E-W trending L-j3 set. Fracture patterns show intensity and density ranging from 11.2395- 53.3443 m-1 and 85.2747- 629.5928 m-2 respectively. Joints in the NE-SW show high dilation and low slip tendencies given a NW-SE directed maximum principal horizontal stress σH stress field. The units of the Abakaliki Formation show better connectivity and lower permeability anisotropy as both fracture systems are well developed in those units. These joints, having formed in the period leading up to the Santonian inversion would have been ideal conduits for migration and flow of hydrocarbon and mineral fluids. The Cross-Fold System precedes the folding episode in the Santonian period and is likely a result of overpressure conditions due to disequilibrium compaction in the Albian- Turonian strata in an initial compressive regional tectonic stress field. The Longitudinal System formed later and is related to the outer-arc flexure of the folded units taking advantage of the nascent cleavage structures in the folded shale units.
{"title":"Analysis of Joints Patterns in Albian to Santonian Strata on the Eastern Flank of the Abakaliki Anticlinorium: Implications on Paleostress Conditions and Fluid Flow Properties in an Unconventional Petroleum System","authors":"I. Okonkwo, O. Igwe","doi":"10.5539/esr.v12n1p31","DOIUrl":"https://doi.org/10.5539/esr.v12n1p31","url":null,"abstract":"An analysis of joint patterns were carried out on multiple exposures in Albian to Turonian strata belonging to the Abakaliki Formation (Asu River Group) and the Eze-Aku Formation (Eze-Aku Group) on the eastern flank of the Abakaliki Anticlinorium of the Southern Benue Trough. The analysis was carried out using FracPaQ a MATLAB based toolbox for quantification of fracture patterns. The tool was used to calculate fracture density, and intensity of the traces; to quantify scaling distributions, and to determine dilation tendencies, slip tendencies, and to quantify connectivity, and fluid flow directions. Analysis show the presence of two major joint systems: A Major Cross-Fold Joint (CF-J) system -orthogonal to the regional fold axes- consisting of the CF-J1 set trending NW/SE (315±5°), and a subordinate Longitudinal Joint System (L-J) -subparallel to the fold axes- consisting of a NE-SW L-j1 set, an ENE-WSW (60°±5°) L-j2 set, and an E-W trending L-j3 set. Fracture patterns show intensity and density ranging from 11.2395- 53.3443 m-1 and 85.2747- 629.5928 m-2 respectively. Joints in the NE-SW show high dilation and low slip tendencies given a NW-SE directed maximum principal horizontal stress σH stress field. The units of the Abakaliki Formation show better connectivity and lower permeability anisotropy as both fracture systems are well developed in those units. These joints, having formed in the period leading up to the Santonian inversion would have been ideal conduits for migration and flow of hydrocarbon and mineral fluids. The Cross-Fold System precedes the folding episode in the Santonian period and is likely a result of overpressure conditions due to disequilibrium compaction in the Albian- Turonian strata in an initial compressive regional tectonic stress field. The Longitudinal System formed later and is related to the outer-arc flexure of the folded units taking advantage of the nascent cleavage structures in the folded shale units.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84876484","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}
U. Oduah, Emmanuel Joel, J. Izunobi, Olubunmi Ayoola Nubi, S. Popoola, N. Njoku-Achu, O. Ajileye, D. Obiora, A. Chukwude, B. Rabiu
World climate continues to deteriorate at varying rates in spite of different anthropogenic mitigative and adaptive interventions. Conversely, the gravitational force fields of the sun and moon hold Earth in orbit, amongst others. Herein, we explore the impacts of changes in these gravitational fields on global climate and examine their influences on natural events, such as ocean tides, volcanoes, geomagnetic storms and movement of tectonic plates. Beyond reports on greenhouse effect and mass transport, we discuss the influence of gravity on tidal bulges, melting glaciers, condensable atmosphere and other events, such as El Niño and La Niña, and correlate their typically subtle impacts on climate worldwide with variations in Earth’s gravity. The intention is to highlight other causative factors implicated in climatic change without diminishing the contributions of greenhouse gasses and other factors, which are currently regarded, by specialists and lay-public alike, as the major culprits of climate change. We submit that the shifts in Earth’s gravitational fields to sustain equilibrium and remain in orbit can manifest as perturbations of atmospheric temperatures, pressures and air concentrations as well as volume changes and ion effects; in hydrological bodies, and are some of the non-anthropogenic agents driving changes in global climate. We surmise, therefore, that the influence of changes in gravity, albeit subtle, on climate change is significant. It is envisaged that highlighting these subtle agents of change would intensify efforts toward ameliorating and/or eliminating drastic and deleterious changes in climate as well as at embracing adaptive measures at local and international levels.
{"title":"Effects of Variations in Earth’s Gravitational Force Fields on Climate Change","authors":"U. Oduah, Emmanuel Joel, J. Izunobi, Olubunmi Ayoola Nubi, S. Popoola, N. Njoku-Achu, O. Ajileye, D. Obiora, A. Chukwude, B. Rabiu","doi":"10.5539/esr.v12n1p16","DOIUrl":"https://doi.org/10.5539/esr.v12n1p16","url":null,"abstract":"World climate continues to deteriorate at varying rates in spite of different anthropogenic mitigative and adaptive interventions. Conversely, the gravitational force fields of the sun and moon hold Earth in orbit, amongst others. Herein, we explore the impacts of changes in these gravitational fields on global climate and examine their influences on natural events, such as ocean tides, volcanoes, geomagnetic storms and movement of tectonic plates. Beyond reports on greenhouse effect and mass transport, we discuss the influence of gravity on tidal bulges, melting glaciers, condensable atmosphere and other events, such as El Niño and La Niña, and correlate their typically subtle impacts on climate worldwide with variations in Earth’s gravity. The intention is to highlight other causative factors implicated in climatic change without diminishing the contributions of greenhouse gasses and other factors, which are currently regarded, by specialists and lay-public alike, as the major culprits of climate change. We submit that the shifts in Earth’s gravitational fields to sustain equilibrium and remain in orbit can manifest as perturbations of atmospheric temperatures, pressures and air concentrations as well as volume changes and ion effects; in hydrological bodies, and are some of the non-anthropogenic agents driving changes in global climate. We surmise, therefore, that the influence of changes in gravity, albeit subtle, on climate change is significant. It is envisaged that highlighting these subtle agents of change would intensify efforts toward ameliorating and/or eliminating drastic and deleterious changes in climate as well as at embracing adaptive measures at local and international levels.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78561294","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}
A recently proposed glacial history paradigm (new paradigm) explains previously ignored Saline-Smoky Hill River drainage divide area topographic map drainage system and erosional landform evidence by headward erosion of the east-oriented Saline River valley across large and prolonged south-oriented meltwater floods which flowed in complexes of closely-spaced anastomosing channels. The eastward sloping drainage divide extends from the Saline River’s western Kansas headwaters between the Saline River (north) and the Smoky Hill River (south) until in central Kansas the Smoky Hill River turns in a southeast and then north direction to join the Saline River with their combined flow continuing as the Smoky Hill River in an east direction to join the Republican River with the combined flow then becoming the Kansas River. Evidence for closely-spaced south-oriented anastomosing channels consists of previously undescribed low points (divide crossings) which are found along the drainage divide and which link north-oriented Saline River tributaries with south-oriented Smoky Hill River tributaries. Evidence that Saline River valley headward erosion beheaded and reversed south-oriented anastomosing channels also consists of the numerous low points along the drainage divide and of barbed tributaries to the now north-oriented Saline River tributaries which suggest large south-oriented meltwater floods extended much further west than commonly accepted glacial history interpretations permit. The topographic map evidence is consistent with the new paradigm interpretation that a thick continental icesheet by its weight and by deep erosion created and occupied a deep “hole” as massive south-oriented meltwater floods flowed across the rising deep “hole” rim until the deep “hole” rim uplift diverted the floodwaters toward what became the deep “hole’s” only remaining southern outlet (the Mississippi River valley).
{"title":"Using a New Cenozoic Glacial History Paradigm to Explain Saline-Smoky Hill River Drainage Divide Area Topographic Map Evidence: Kansas, USA","authors":"E. Clausen","doi":"10.5539/esr.v12n1p1","DOIUrl":"https://doi.org/10.5539/esr.v12n1p1","url":null,"abstract":"A recently proposed glacial history paradigm (new paradigm) explains previously ignored Saline-Smoky Hill River drainage divide area topographic map drainage system and erosional landform evidence by headward erosion of the east-oriented Saline River valley across large and prolonged south-oriented meltwater floods which flowed in complexes of closely-spaced anastomosing channels. The eastward sloping drainage divide extends from the Saline River’s western Kansas headwaters between the Saline River (north) and the Smoky Hill River (south) until in central Kansas the Smoky Hill River turns in a southeast and then north direction to join the Saline River with their combined flow continuing as the Smoky Hill River in an east direction to join the Republican River with the combined flow then becoming the Kansas River. Evidence for closely-spaced south-oriented anastomosing channels consists of previously undescribed low points (divide crossings) which are found along the drainage divide and which link north-oriented Saline River tributaries with south-oriented Smoky Hill River tributaries. Evidence that Saline River valley headward erosion beheaded and reversed south-oriented anastomosing channels also consists of the numerous low points along the drainage divide and of barbed tributaries to the now north-oriented Saline River tributaries which suggest large south-oriented meltwater floods extended much further west than commonly accepted glacial history interpretations permit. The topographic map evidence is consistent with the new paradigm interpretation that a thick continental icesheet by its weight and by deep erosion created and occupied a deep “hole” as massive south-oriented meltwater floods flowed across the rising deep “hole” rim until the deep “hole” rim uplift diverted the floodwaters toward what became the deep “hole’s” only remaining southern outlet (the Mississippi River valley).","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77792083","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}
H. Nestor, Kouadio Fossou Jean Luc Hervé, Allialy Marc Ephrem, Kouassi Brice Roland, Adingra Martial Pohn Koffi
Located in the south-west part of the Fettekro greenstone belt, Agbaou gold deposit is marked by three major lithological units: (i) a volcano-plutonic unit composed of basaltic to andesitic lavas, amphibolites, chlorite-schists and sills of microdiorite and microgabbro; (ii) a volcano-sedimentary unit containing pyroclastic lavas (basaltic and dacitic) and sediments (shale and grauwacke); (iii) the late felsic dikes (rhyolite and rhyodacite) probably contemporary with the formation of granitoids form the third unit. These host rocks are mostly intensely deformed and altered. Alteration phenomena were revealed by the high values in fire loss, the decreasing of silica contents, the sometimes high values of alkaline for rocks also basic, the constant depletion in LREE and LILE. The Eu and Nb negative anomalies reveal a crustal contamination of magmatic series. Basaltic lavas are volcanic arc tholeiites nearing N-MORB type; they are associated to a magmatogenesis of ocean floor. Their magmatic source would probably be spinel lherzolitic type. Andesites have a calc-alkaline composition and seem far link to active subduction margin. Geodynamics context would be that of an area where transcurrent faults of lithospheric extension generate heat corridors able of generating by fusion the andesitic calc-alkaline magma. This context would probably be the one that prevailed during the establishment of the gold mineralization. Pyroclastic rocks of dacitic composition as acid lavas (rhyolite and rhyodacite) have also evolved in this same geotectonic context. Plutonic rocks are located in arc-volcanic granites field, while metasediment are linked to active continental margin field.
{"title":"Geochemistry of Volcano-sedimentary and Plutonic Formations of the Agbaou Gold Deposit, Ivory Coast","authors":"H. Nestor, Kouadio Fossou Jean Luc Hervé, Allialy Marc Ephrem, Kouassi Brice Roland, Adingra Martial Pohn Koffi","doi":"10.5539/esr.v11n1p76","DOIUrl":"https://doi.org/10.5539/esr.v11n1p76","url":null,"abstract":"Located in the south-west part of the Fettekro greenstone belt, Agbaou gold deposit is marked by three major lithological units: (i) a volcano-plutonic unit composed of basaltic to andesitic lavas, amphibolites, chlorite-schists and sills of microdiorite and microgabbro; (ii) a volcano-sedimentary unit containing pyroclastic lavas (basaltic and dacitic) and sediments (shale and grauwacke); (iii) the late felsic dikes (rhyolite and rhyodacite) probably contemporary with the formation of granitoids form the third unit. These host rocks are mostly intensely deformed and altered. Alteration phenomena were revealed by the high values in fire loss, the decreasing of silica contents, the sometimes high values of alkaline for rocks also basic, the constant depletion in LREE and LILE. The Eu and Nb negative anomalies reveal a crustal contamination of magmatic series. Basaltic lavas are volcanic arc tholeiites nearing N-MORB type; they are associated to a magmatogenesis of ocean floor. Their magmatic source would probably be spinel lherzolitic type. Andesites have a calc-alkaline composition and seem far link to active subduction margin. Geodynamics context would be that of an area where transcurrent faults of lithospheric extension generate heat corridors able of generating by fusion the andesitic calc-alkaline magma. This context would probably be the one that prevailed during the establishment of the gold mineralization. Pyroclastic rocks of dacitic composition as acid lavas (rhyolite and rhyodacite) have also evolved in this same geotectonic context. Plutonic rocks are located in arc-volcanic granites field, while metasediment are linked to active continental margin field.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73713165","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}
Romeo Kuete Noupa, Paul Gustave Fowé Kwetche, Steve Imeli Talla, Lawane Esaie Silvere, Joseph Rene Lavenir Binyet Ndjebakal, M. Bessong, M. Ntamak-Nida
The P10 well is located offshore, in the Northern part of the Rio Del Rey basin in southwest Cameroon. Although the Rio Del Rey basin is the most prolific coastal basin in Cameroon given the production results from several fields in the southern part, yet it remains very little explored in its northern part. This work evaluation the petroleum potential in the northern part of the Basin using a combination of the "Quick Look" interpretation of the logs recorded in well P10 and "complex matrix" facies analysis of the different lithofacies through the neutron porosity - bulk density (NPHI-RHOB) and delta time sonic - bulk density (DT-RHOB) diagrams. The composite log includes the Gamma Ray log; Caliper log; Deep Resistivity log; neutron porosity log and bulk density log. In addition to this composite log, a geological end of well report is completed to refine the results. Ten (10) near sand/sandstone reservoirs were delineated between 950 and 1803 TVD m (true vertical depth in meter) with very good porosities (12% <Φ< 30%) as well as a mineralogical composition dominated by quartz. Clay volumes are relatively lower than 18% except in reservoirs R5 and R6 where they are around 24%, giving the latter a sandy-clay lithology. Reservoirs R2 and R4 contain oil, the latter with a WOC (Water Oil Contact) at ~1172 m and a GOC (Gas Oil Contact) at 1169 m. Reservoirs R6; R7; R8; R9; R10 all contain Gas and Water with WGC (Water Gas Contact) located at ~1431 m; 1530 m; 1690 m and ~1790 m respectively. In the light of these results, there is a clear dominance of gaseous hydrocarbon reservoirs over oil-impregnated ones in the study area. The results provided by this work can serve as baseline data for future oil and gas exploration projects in the northern part of the Rio Del Ray Basin.
P10井位于喀麦隆西南部Rio Del Rey盆地北部海域。尽管从南部几个油田的产量来看，Rio Del Rey盆地是喀麦隆最多产的沿海盆地，但其北部的勘探仍然很少。本研究结合了对P10井测井资料的“Quick Look”解释，以及通过中子孔隙度-容重图(NPHI-RHOB)和δ时间声波-容重图(DT-RHOB)对不同岩相进行的“复杂基质”相分析，对盆地北部的石油潜力进行了评价。复合测井包括伽马测井;井径测井;深电阻率测井;中子孔隙度测井和体积密度测井。除了该复合测井外，还完成了井尾地质报告，以完善结果。在950 ~ 1803 TVD m(真垂直深度，单位为米)之间圈定了10个砂/砂岩储层，孔隙度非常好(12% <Φ< 30%)，矿物成分以石英为主。除R5和R6储层粘土含量约为24%外，其余储层粘土含量相对低于18%，为砂粘土岩性。R2和R4储层含油，后者的WOC(水油界面)在~1172 m, GOC(气油界面)在1169 m。水库R6;R7;R8;R9机型;R10均含气和水，WGC(水气接触面)位于~1431 m;1530米;分别为1690 m和~1790 m。研究区气态油气藏明显优于油浸油气藏。这项工作提供的结果可以作为未来Rio Del Ray盆地北部油气勘探项目的基线数据。
{"title":"Well Log Lithological Analysis and Petrophysical Parameters Calculation of Miocene to Recent Formation Reservoirs in Well P10, Offshore, Northern Rio Del Rey Basin (Southwest Cameroon, Gulf of Guinea)","authors":"Romeo Kuete Noupa, Paul Gustave Fowé Kwetche, Steve Imeli Talla, Lawane Esaie Silvere, Joseph Rene Lavenir Binyet Ndjebakal, M. Bessong, M. Ntamak-Nida","doi":"10.5539/esr.v11n1p64","DOIUrl":"https://doi.org/10.5539/esr.v11n1p64","url":null,"abstract":"The P10 well is located offshore, in the Northern part of the Rio Del Rey basin in southwest Cameroon. Although the Rio Del Rey basin is the most prolific coastal basin in Cameroon given the production results from several fields in the southern part, yet it remains very little explored in its northern part. This work evaluation the petroleum potential in the northern part of the Basin using a combination of the \"Quick Look\" interpretation of the logs recorded in well P10 and \"complex matrix\" facies analysis of the different lithofacies through the neutron porosity - bulk density (NPHI-RHOB) and delta time sonic - bulk density (DT-RHOB) diagrams. The composite log includes the Gamma Ray log; Caliper log; Deep Resistivity log; neutron porosity log and bulk density log. In addition to this composite log, a geological end of well report is completed to refine the results. Ten (10) near sand/sandstone reservoirs were delineated between 950 and 1803 TVD m (true vertical depth in meter) with very good porosities (12% <Φ< 30%) as well as a mineralogical composition dominated by quartz. Clay volumes are relatively lower than 18% except in reservoirs R5 and R6 where they are around 24%, giving the latter a sandy-clay lithology. Reservoirs R2 and R4 contain oil, the latter with a WOC (Water Oil Contact) at ~1172 m and a GOC (Gas Oil Contact) at 1169 m. Reservoirs R6; R7; R8; R9; R10 all contain Gas and Water with WGC (Water Gas Contact) located at ~1431 m; 1530 m; 1690 m and ~1790 m respectively. In the light of these results, there is a clear dominance of gaseous hydrocarbon reservoirs over oil-impregnated ones in the study area. The results provided by this work can serve as baseline data for future oil and gas exploration projects in the northern part of the Rio Del Ray Basin.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78805586","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}
A recently proposed and fundamentally different Cenozoic geology and glacial history paradigm (new paradigm) is used to explain previously reported and other anomalous Monongahela River drainage basin drainage system evidence (observable on detailed topographic maps in the form of barbed tributaries, asymmetric tributary drainage basins, large abandoned meander cutoffs, and poorly explained transverse drainages and abandoned transverse drainages). The north-oriented Monongahela River drainage system according to the accepted Cenozoic geology and glacial history paradigm (accepted paradigm) originated during preglacial times and was blocked by continental icesheets to form today’s Ohio River. Based on Missouri River drainage basin topographic map evidence the new paradigm predicts the Monongahela River drainage system developed during immense and prolonged south- and southwest-oriented continental icesheet melt water floods. The new paradigm also predicts icesheet caused regional uplift created a deep “hole” in which a thick icesheet was located and which forced south-oriented melt water floods to flow in southwest directions along the deep “hole’s” southeast rim (now the Ohio River-Atlantic Ocean drainage divide) until continued deep “hole” rim uplift and the deep valley headward erosion from space being opened up by icesheet melting reversed the flow direction to create the north-oriented Monongahela River drainage system. This new paradigm interpretation explains previously reported and other anomalous Monongahela River drainage system topographic map evidence and suggests the Monongahela River drainage system developed while a continental icesheet melted and not during preglacial time as has been commonly reported.
{"title":"How a New Cenozoic Geology and Glacial History Paradigm Explains Anomalous Monongahela River Drainage Basin Topographic Map Evidence, PA, WV and MD, USA","authors":"E. Clausen","doi":"10.5539/esr.v11n1p47","DOIUrl":"https://doi.org/10.5539/esr.v11n1p47","url":null,"abstract":"A recently proposed and fundamentally different Cenozoic geology and glacial history paradigm (new paradigm) is used to explain previously reported and other anomalous Monongahela River drainage basin drainage system evidence (observable on detailed topographic maps in the form of barbed tributaries, asymmetric tributary drainage basins, large abandoned meander cutoffs, and poorly explained transverse drainages and abandoned transverse drainages). The north-oriented Monongahela River drainage system according to the accepted Cenozoic geology and glacial history paradigm (accepted paradigm) originated during preglacial times and was blocked by continental icesheets to form today’s Ohio River. Based on Missouri River drainage basin topographic map evidence the new paradigm predicts the Monongahela River drainage system developed during immense and prolonged south- and southwest-oriented continental icesheet melt water floods. The new paradigm also predicts icesheet caused regional uplift created a deep “hole” in which a thick icesheet was located and which forced south-oriented melt water floods to flow in southwest directions along the deep “hole’s” southeast rim (now the Ohio River-Atlantic Ocean drainage divide) until continued deep “hole” rim uplift and the deep valley headward erosion from space being opened up by icesheet melting reversed the flow direction to create the north-oriented Monongahela River drainage system. This new paradigm interpretation explains previously reported and other anomalous Monongahela River drainage system topographic map evidence and suggests the Monongahela River drainage system developed while a continental icesheet melted and not during preglacial time as has been commonly reported.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80512469","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}
In this study, the Advanced Research Weather Research and Forecasting (WRF) model was adopted to investigate the mechanical and thermal forcing effects associated with the New Guinea Highland (NGH) on Madden-Julian Oscillation (MJO) propagation and rainfall formation and enhancement mechanisms over the island of New Guinea. Our results show that both forces affect the propagation of the MJO07-08, resulting in orographic rainfall production. Even though each forcing helps produce orographic rainfall, the mechanical forcing of the NGH plays a much larger role in the orographic blocking than the thermal forcing. We also found two flow regimes associated with the propagation of MJO07-08 over the NGH. First, in the flow-around regime, the MJO and its associated convective system split around the NGH due to the strong orographic blocking. We can observe this splitting when looking at the splitting stage. Second, the flow-over regime could occur when the mountain is lower than its original height or the flow has a smaller Froude number. A series of numerical experiments indicate that the maximum orographic rainfall increases with increased mountain height; however, the maximum orographic rain decreases when the flow transitions to the flow-around regime. Finally, some common ingredients for orographic rainfall associated with the MJO07-08 passing over the NGH are consistent with those found for tropical cyclones passing over mountains.
采用WRF (Advanced Research Weather Research and Forecasting)模式，研究了新几内亚高原(NGH)对马登-朱利安涛动(Madden-Julian Oscillation, MJO)传播、降雨形成和增强机制的机械和热强迫效应。我们的研究结果表明，这两种力都影响了MJO07-08的传播，导致了地形降雨的产生。尽管每种强迫都有助于产生地形降雨，但天然气水合物的机械强迫在地形阻塞中所起的作用要比热强迫大得多。我们还发现了与MJO07-08在天然气水合物上传播有关的两种流动形式。首先，在绕流状态下，由于强大的地形阻塞，MJO及其相关的对流系统在天然气水合物周围分裂。我们可以在观察分裂阶段时观察到这种分裂。其次，当山的高度低于山的原始高度或流量的弗劳德数较小时，可能出现过流状态。一系列数值试验表明，最大地形降雨量随海拔的增加而增加;然而，当气流转变为绕流状态时，最大地形雨量减少。最后，与MJO07-08经过NGH有关的地形降雨的一些共同成分与经过山脉的热带气旋一致。
{"title":"Effects of Mechanical and Thermal Forcing on the Enhancement and Ingredients of Orographic Rain Associated with the 2007-08 Madden-Julian Oscillation Passing the New Guinea Highlands","authors":"Justin G. Riley, Yuh-Lang Lin","doi":"10.5539/esr.v11n1p25","DOIUrl":"https://doi.org/10.5539/esr.v11n1p25","url":null,"abstract":"In this study, the Advanced Research Weather Research and Forecasting (WRF) model was adopted to investigate the mechanical and thermal forcing effects associated with the New Guinea Highland (NGH) on Madden-Julian Oscillation (MJO) propagation and rainfall formation and enhancement mechanisms over the island of New Guinea. Our results show that both forces affect the propagation of the MJO07-08, resulting in orographic rainfall production. Even though each forcing helps produce orographic rainfall, the mechanical forcing of the NGH plays a much larger role in the orographic blocking than the thermal forcing. We also found two flow regimes associated with the propagation of MJO07-08 over the NGH. First, in the flow-around regime, the MJO and its associated convective system split around the NGH due to the strong orographic blocking. We can observe this splitting when looking at the splitting stage. Second, the flow-over regime could occur when the mountain is lower than its original height or the flow has a smaller Froude number. A series of numerical experiments indicate that the maximum orographic rainfall increases with increased mountain height; however, the maximum orographic rain decreases when the flow transitions to the flow-around regime. Finally, some common ingredients for orographic rainfall associated with the MJO07-08 passing over the NGH are consistent with those found for tropical cyclones passing over mountains.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83908264","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}
This work deals with the petrographic and geotechnical characterization of rocks from the N'goura massif with focus on their use in civil engineering. The study area is located in central southern Chad, about 205km to the north of N'Djamena. The N'goura massif is monzogranitic with two micas. The rocks outcrop as blocks, slabs and balls displaying fine, medium and coarse grained minerals. Monzogranite is composed of 34% quartz, 32% alkali feldspar, 26% plagioclase, 4% biotite, 2% muscovite and 1% chlorite on average. Geotechnical data show that the aggregates obtained from this rock have a Los Angeles coefficient ranging from 22.70 to 38.70% with an average of 30.70%, a Microdeval coefficient ranging from 4 to 13% with an average of 8.5% and a dynamic fragmentation coefficient ranging from 11.43 to 18.57% with an average of 15%. These results indicate that the studied materials are suitable to be used for construction and civil engineering works. The correlation between petrographic and geotechnical data reveals that the size (texture), grain structure and mineralogical composition (Qtz, Kfs and Bt+Ms+Chl+Ser) have an influence on the geotechnical behavior of these materials.
{"title":"Petrographic and Geotechnical Characterization of Granites from the N’Goura Massif (Center-Sud/Tchad): Implication for their Used in Civil Engineering","authors":"Al-hadj Hamid Zagalo, Tcheumenak Kouémo Jules, Kwékam Maurice, Allaramadji Dounia, P. Rochette","doi":"10.5539/esr.v11n1p15","DOIUrl":"https://doi.org/10.5539/esr.v11n1p15","url":null,"abstract":"This work deals with the petrographic and geotechnical characterization of rocks from the N'goura massif with focus on their use in civil engineering. The study area is located in central southern Chad, about 205km to the north of N'Djamena. The N'goura massif is monzogranitic with two micas. The rocks outcrop as blocks, slabs and balls displaying fine, medium and coarse grained minerals. Monzogranite is composed of 34% quartz, 32% alkali feldspar, 26% plagioclase, 4% biotite, 2% muscovite and 1% chlorite on average. Geotechnical data show that the aggregates obtained from this rock have a Los Angeles coefficient ranging from 22.70 to 38.70% with an average of 30.70%, a Microdeval coefficient ranging from 4 to 13% with an average of 8.5% and a dynamic fragmentation coefficient ranging from 11.43 to 18.57% with an average of 15%. These results indicate that the studied materials are suitable to be used for construction and civil engineering works. The correlation between petrographic and geotechnical data reveals that the size (texture), grain structure and mineralogical composition (Qtz, Kfs and Bt+Ms+Chl+Ser) have an influence on the geotechnical behavior of these materials.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90151253","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}
V. Ramaroson, J. Rajaobelison, L. P. Fareze, F. A. Razafitsalama, Mamiseheno Rasolofonirina, C. Rakotomalala
In the “Global Network of Isotopes in Precipitation” database, Antananarivo has two distinct datasets from two stations. Thirty-four years separate the two datasets. This study aims on the one hand to depict the variations of the water stable isotopes composition of precipitations from the two stations and understand their origins, mainly in relation to meteorological factors. On the other hand, the Antananarivo data are compared with regional and international data to identify other sources of isotope composition variability in precipitation. Isotope records showed that after thirty-four-year gap, summer and winter (the two main seasons) precipitations are more enriched in heavy isotopes. The precipitation amount fluctuation would mostly contribute to this temporal variation. Opposite to summer and winter precipitations, inter-season rainfalls have similar isotope values after thirty-four years. The two stations are geographically close and the spatial aspect is therefore negligible since there are no latitude nor altitude effects on the isotope composition of precipitations. Regarding the second order parameter d-excess, the monthly mean values from both stations are higher than 100/00 and could indicate moisture recycling. The comparison with regional/international data showed that the isotope variability in precipitation is primarily due to precipitation amount effect, different moisture source, the stations distance from it and the change of meteorological factors along the moisture trajectory.
{"title":"Water Stable Isotope Composition of Precipitations at Two Stations in Antananarivo-Madagascar: A Comparative Study","authors":"V. Ramaroson, J. Rajaobelison, L. P. Fareze, F. A. Razafitsalama, Mamiseheno Rasolofonirina, C. Rakotomalala","doi":"10.5539/esr.v11n1p1","DOIUrl":"https://doi.org/10.5539/esr.v11n1p1","url":null,"abstract":"In the “Global Network of Isotopes in Precipitation” database, Antananarivo has two distinct datasets from two stations. Thirty-four years separate the two datasets. This study aims on the one hand to depict the variations of the water stable isotopes composition of precipitations from the two stations and understand their origins, mainly in relation to meteorological factors. On the other hand, the Antananarivo data are compared with regional and international data to identify other sources of isotope composition variability in precipitation. Isotope records showed that after thirty-four-year gap, summer and winter (the two main seasons) precipitations are more enriched in heavy isotopes. The precipitation amount fluctuation would mostly contribute to this temporal variation. Opposite to summer and winter precipitations, inter-season rainfalls have similar isotope values after thirty-four years. The two stations are geographically close and the spatial aspect is therefore negligible since there are no latitude nor altitude effects on the isotope composition of precipitations. Regarding the second order parameter d-excess, the monthly mean values from both stations are higher than 100/00 and could indicate moisture recycling. The comparison with regional/international data showed that the isotope variability in precipitation is primarily due to precipitation amount effect, different moisture source, the stations distance from it and the change of meteorological factors along the moisture trajectory.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88001285","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}
Aurélien Manfred Mbenoun, G. F. N. Ngon, M. B. Mbog, R. Y. Fouateu, P. Bilong
The present study, which focuses on the behavior of gold and its accompanying chemical elements developed on an alteration profile, is carried out in a humid equatorial zone at Mintom in South Cameroon (Central Africa). The methodology used to achieve the results obtained focused on the description of the morphology of the outcrop, the petrography of the rock studied, the study of heavy minerals accompanying gold in the weathering materials on smear slides, mineralogical analysis of weathering materials by X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis of gold and geochemical analyzes by ICP - AES and ICP - MS of weathering materials. The main results obtained from this methodology inform us that on the petrographic level the main rock studied is the gold-bearing quartz vein located in Zom, consisting mainly of quartz and opaque minerals. Morphologically, the weathering materials developed on this granite basement present an advanced ABC-type profile characterized by a significant thickness (4 to 6 m). The morphological and chemical characters of the gold particles have evolved from the mineralized zone to the surface. This development was marked by an increase in blunt, rounded grains. Morphoscopy and scanning electron microscopy of the gold particles have shown hollow, blunt to sub-blunt grains, non-evolved free particles, and evolved free particles, respectively. In most samples of weathered material gold is found in association with chemical elements such as Ag, Cr, Co, Cu, Ni, V and figure 10 show identical behavior between these chemical elements and gold, but particularly between silver and gold, which would testify to an identical origin. Au concentrations are very high in most samples of weathering material. Also, these samples of altered materials with a high proportion of gold (0.01 to 2.28 ppm) also present high concentrations of silver (Ag) which justifies that the occurrence or the gold deposit is associated with silver and can be exploited as a geochemical parameter to prospect for gold in the study area.
{"title":"Study of the Behavior of Gold and Accompanying Chemical Elements in Weathering Profile on a Quartz Vein in Mintom (South Cameroon, Central Africa)","authors":"Aurélien Manfred Mbenoun, G. F. N. Ngon, M. B. Mbog, R. Y. Fouateu, P. Bilong","doi":"10.5539/esr.v10n2p54","DOIUrl":"https://doi.org/10.5539/esr.v10n2p54","url":null,"abstract":"The present study, which focuses on the behavior of gold and its accompanying chemical elements developed on an alteration profile, is carried out in a humid equatorial zone at Mintom in South Cameroon (Central Africa). The methodology used to achieve the results obtained focused on the description of the morphology of the outcrop, the petrography of the rock studied, the study of heavy minerals accompanying gold in the weathering materials on smear slides, mineralogical analysis of weathering materials by X-ray diffraction (XRD), scanning electron microscopy (SEM) analysis of gold and geochemical analyzes by ICP - AES and ICP - MS of weathering materials. The main results obtained from this methodology inform us that on the petrographic level the main rock studied is the gold-bearing quartz vein located in Zom, consisting mainly of quartz and opaque minerals. Morphologically, the weathering materials developed on this granite basement present an advanced ABC-type profile characterized by a significant thickness (4 to 6 m). The morphological and chemical characters of the gold particles have evolved from the mineralized zone to the surface. This development was marked by an increase in blunt, rounded grains. Morphoscopy and scanning electron microscopy of the gold particles have shown hollow, blunt to sub-blunt grains, non-evolved free particles, and evolved free particles, respectively. In most samples of weathered material gold is found in association with chemical elements such as Ag, Cr, Co, Cu, Ni, V and figure 10 show identical behavior between these chemical elements and gold, but particularly between silver and gold, which would testify to an identical origin. Au concentrations are very high in most samples of weathering material. Also, these samples of altered materials with a high proportion of gold (0.01 to 2.28 ppm) also present high concentrations of silver (Ag) which justifies that the occurrence or the gold deposit is associated with silver and can be exploited as a geochemical parameter to prospect for gold in the study area.","PeriodicalId":11486,"journal":{"name":"Earth Science Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2021-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80136447","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}
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