Pub Date : 2017-05-16DOI: 10.4172/2381-8719.1000292
P. ZooZame, Mbida Yem, Yene Atangana Jq, E. Ekomane
The upper Dja series consists of carbonates and shales deposits that date 580 ± 150 Ma. Petrography and mineral chemistry studies helped to differentiate this series into many sequences including massive limestone layers with calcite (CaO3) contents of about 30 to 42%. In order to determine the subsurface distribution of these sequences, a geophysical prospection campaign was carried out in which a total of 24 vertical resistivity soundings were recorded over a surface area of 9 km2. The processing and interpretation of data using the IX1D and OpendTect modeling tools permitted the distinction of two massive limestone layers in the upper Dja series. The first layer of about 10 to 35 m thick and outcrop in few places is characterized by resistivity ranging between 1110 and 2377 Ωm, while the second layer located beyond 50 m deep is separated by a very conductive clay stone layer with a capped thickness of 15 to 35 m. 3D modeling of the top and base of these formations indicates that, the whole Upper Dja series of about 190 m thick presents folded structure. These results can constitute a useful base of information in regards to a large scale economic study of the Upper Dja limestone series.
{"title":"Geophysical Assessment of the Upper Dja Series Using Electrical Resistivity Data","authors":"P. ZooZame, Mbida Yem, Yene Atangana Jq, E. Ekomane","doi":"10.4172/2381-8719.1000292","DOIUrl":"https://doi.org/10.4172/2381-8719.1000292","url":null,"abstract":"The upper Dja series consists of carbonates and shales deposits that date 580 ± 150 Ma. Petrography and mineral \u0000 chemistry studies helped to differentiate this series into many sequences including massive limestone layers with \u0000 calcite (CaO3) contents of about 30 to 42%. In order to determine the subsurface distribution of these sequences, a \u0000 geophysical prospection campaign was carried out in which a total of 24 vertical resistivity soundings were recorded \u0000 over a surface area of 9 km2. The processing and interpretation of data using the IX1D and OpendTect modeling tools \u0000 permitted the distinction of two massive limestone layers in the upper Dja series. The first layer of about 10 to 35 m \u0000 thick and outcrop in few places is characterized by resistivity ranging between 1110 and 2377 Ωm, while the second \u0000 layer located beyond 50 m deep is separated by a very conductive clay stone layer with a capped thickness of 15 to \u0000 35 m. 3D modeling of the top and base of these formations indicates that, the whole Upper Dja series of about 190 m \u0000 thick presents folded structure. These results can constitute a useful base of information in regards to a large scale \u0000 economic study of the Upper Dja limestone series.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"12 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2017-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76671364","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}
Pub Date : 2017-05-04DOI: 10.4172/2381-8719.1000287
Thornbush Mj
This review considers the current literature on sinkhole formation and occurrence. It incorporates several examples from around the world in order to gain a broader geographical scope on the problem. Challenges associated with sinkholes center around atmospheric acidification (pollution) and the formation of dissolution sinkholes. In addition, urbanization and its imposed changes on surface drainage as well as aquifer contamination also bear upon this geohazard. Solutions have been grasped through the deployment of geophysical techniques, in particular GPR. Engineering solutions are presented and critically discussed. Preventative planning based on early detection (through geophysical, GIS and multivariate analysis plus modeling, and possibly remote sensing techniques) are among the most effective available solutions. More research is needed to investigate the effects of increasing surface temperatures and interactions (synergies) with pollution.
{"title":"Part 1: Contemporary Challenges and Current Solutions in Sinkhole Occurrence and Mitigation","authors":"Thornbush Mj","doi":"10.4172/2381-8719.1000287","DOIUrl":"https://doi.org/10.4172/2381-8719.1000287","url":null,"abstract":"This review considers the current literature on sinkhole formation and occurrence. It incorporates several examples from around the world in order to gain a broader geographical scope on the problem. Challenges associated with sinkholes center around atmospheric acidification (pollution) and the formation of dissolution sinkholes. In addition, urbanization and its imposed changes on surface drainage as well as aquifer contamination also bear upon this geohazard. Solutions have been grasped through the deployment of geophysical techniques, in particular GPR. Engineering solutions are presented and critically discussed. Preventative planning based on early detection (through geophysical, GIS and multivariate analysis plus modeling, and possibly remote sensing techniques) are among the most effective available solutions. More research is needed to investigate the effects of increasing surface temperatures and interactions (synergies) with pollution.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"22 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2017-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81407217","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}
Pub Date : 2017-05-04DOI: 10.4172/2381-8719.1000286
Thornbush Mj
Solutional sinkholes pose a serious threat in karst regions. Few studies have actually addressed the mechanisms of their formation in any great detail (for solutional and collapse sinkholes) to enable an understanding of the sinkhole hazard in a scenario of global change. A brief case study is developed for Florida, USA as a state plagued by most of the contemporary challenges of sinkhole formation. This paper addresses work that has already made a contribution to an understanding of sinkhole formation and development and makes its own contribution by detailing a case study for Seffner, Florida, where Jeffrey Bush was engulfed by a collapse sinkhole in 2014 that was subsequently reactivated in 2015. The findings from this case study reveal a high incidence of sinkhole occurrence when temperatures are low and precipitation is also low in winter months (especially January). This suggests that temperature (rather than precipitation) may be the principal driving climatic factor, along with associated human impacts.
{"title":"Part 2: Spatial-Temporal Occurrences of Sinkholes as a Complex Geohazard in Florida, USA","authors":"Thornbush Mj","doi":"10.4172/2381-8719.1000286","DOIUrl":"https://doi.org/10.4172/2381-8719.1000286","url":null,"abstract":"Solutional sinkholes pose a serious threat in karst regions. Few studies have actually addressed the mechanisms of their formation in any great detail (for solutional and collapse sinkholes) to enable an understanding of the sinkhole hazard in a scenario of global change. A brief case study is developed for Florida, USA as a state plagued by most of the contemporary challenges of sinkhole formation. This paper addresses work that has already made a contribution to an understanding of sinkhole formation and development and makes its own contribution by detailing a case study for Seffner, Florida, where Jeffrey Bush was engulfed by a collapse sinkhole in 2014 that was subsequently reactivated in 2015. The findings from this case study reveal a high incidence of sinkhole occurrence when temperatures are low and precipitation is also low in winter months (especially January). This suggests that temperature (rather than precipitation) may be the principal driving climatic factor, along with associated human impacts.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"73 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2017-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86399240","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}
Pub Date : 2017-05-02DOI: 10.4172/2381-8719.1000290
Owoyemi Oo, A. Go
Sixty-four bulk samples of two residual lateritic soils forming the subgrade of the failed sections flexible highway pavement linking Ilorin to Mokwa in central Nigeria were investigated. This was with a view to determining the level of variation in the geotechnical properties of soil samples taken systematically within restricted area in two locations underlain by different bed rocks. One set was developed over sandstone formation of the Southern Bida Basin while the other set was developed over migmatite-gneiss. Consistency limits, grain size distribution, specific gravity, compaction, California Bearing Ratio (CBR), permeability and compressibility characteristics of these soils were determined using the British standard procedures 1377. Coefficient of variation was used to measure the degree of variation in the determined properties. The coefficients of variations for the sandstone derived soil (1.68% and 56.86%) are higher than that of the migmatite-gneiss derived soil (1.28%-54.40%). Permeability, linear shrinkage, and coefficient of volume compressibility possess the highest variability. Atterberg limits and derived indices, amount of fines, soaked and unsoaked CBR possess moderate variability, while moisture density parameters (MDD and OMC), natural moisture content and specific gravity exhibits the least variability. In order to prevent design errors, field sampling should be very thorough involving collection of several samples. This approach will eliminate wrong inferences often associated with results of testing of few samples
{"title":"Variability in the Highway Geotechnical Properties of Two Residual Lateritic Soils from Central Nigeria","authors":"Owoyemi Oo, A. Go","doi":"10.4172/2381-8719.1000290","DOIUrl":"https://doi.org/10.4172/2381-8719.1000290","url":null,"abstract":"Sixty-four bulk samples of two residual lateritic soils forming the subgrade of the failed sections flexible highway pavement linking Ilorin to Mokwa in central Nigeria were investigated. This was with a view to determining the level of variation in the geotechnical properties of soil samples taken systematically within restricted area in two locations underlain by different bed rocks. One set was developed over sandstone formation of the Southern Bida Basin while the other set was developed over migmatite-gneiss. Consistency limits, grain size distribution, specific gravity, compaction, California Bearing Ratio (CBR), permeability and compressibility characteristics of these soils were determined using the British standard procedures 1377. Coefficient of variation was used to measure the degree of variation in the determined properties. The coefficients of variations for the sandstone derived soil (1.68% and 56.86%) are higher than that of the migmatite-gneiss derived soil (1.28%-54.40%). Permeability, linear shrinkage, and coefficient of volume compressibility possess the highest variability. Atterberg limits and derived indices, amount of fines, soaked and unsoaked CBR possess moderate variability, while moisture density parameters (MDD and OMC), natural moisture content and specific gravity exhibits the least variability. In order to prevent design errors, field sampling should be very thorough involving collection of several samples. This approach will eliminate wrong inferences often associated with results of testing of few samples","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"357 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2017-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76505887","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}
Pub Date : 2017-05-01DOI: 10.4172/2381-8719.1000289
A. Arisona, M. Nawawi, Ishola Ks, S. Lo
Estimation of response profile in the soil layer from GPR synthetic data using forward modeling of radar data has been applied for reconstruction of 3 layers model without anomaly and 2 layers model with air-filled and water-filled cavity. For synthesizing the models, the reflection profiling and common mid-point (CMP) were used for the radar data in providing framework in order to link subsurface properties and GPR data. The result of the three layers model shows that response profile obtained is similar to lithology models using reflection profiling technique. Whereas, for the CMP the response profile gives oblique and hyperbolic patterns. For the two layers model, a diffraction response with wave travel time that longer in the side compared with the top of anomalous cavity is obtained using reflection profiling technique. Comparison to a GPR synthetic data model shows a good accuracy of the forward modeling.
{"title":"Forward Modeling of Ground Penetrating Radar for the Reconstruction of Models Response Profiles using Synthetic Data","authors":"A. Arisona, M. Nawawi, Ishola Ks, S. Lo","doi":"10.4172/2381-8719.1000289","DOIUrl":"https://doi.org/10.4172/2381-8719.1000289","url":null,"abstract":"Estimation of response profile in the soil layer from GPR synthetic data using forward modeling of radar data has been applied for reconstruction of 3 layers model without anomaly and 2 layers model with air-filled and water-filled cavity. For synthesizing the models, the reflection profiling and common mid-point (CMP) were used for the radar data in providing framework in order to link subsurface properties and GPR data. The result of the three layers model shows that response profile obtained is similar to lithology models using reflection profiling technique. Whereas, for the CMP the response profile gives oblique and hyperbolic patterns. For the two layers model, a diffraction response with wave travel time that longer in the side compared with the top of anomalous cavity is obtained using reflection profiling technique. Comparison to a GPR synthetic data model shows a good accuracy of the forward modeling.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"25 1","pages":"1-6"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73925623","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}
Pub Date : 2017-05-01DOI: 10.4172/2381-8719.1000E121
El-Said Gf
{"title":"A Future Overview of the Usage of Minerals as an Eco-friendly Adsorbent for the Removal of Pollutants","authors":"El-Said Gf","doi":"10.4172/2381-8719.1000E121","DOIUrl":"https://doi.org/10.4172/2381-8719.1000E121","url":null,"abstract":"","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"106 1","pages":"1-1"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79256217","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}
Pub Date : 2017-05-01DOI: 10.4172/2381-8719.1000291
Oluwadare Oa, Osunrinde Ot, Abe Sj, Ojo Bt
There is an insatiable thirst for oil and gas consumption and increased production will be made possible only through effective reservoir characterization and modeling. A suite of wire-line logs for four wells from ‘DEL’ oil field together with 3D seismic data were analyzed for reservoir characterization of the field. Two reservoirs were identified using the resistivity log. A synthetic seismogram was generated in order to perform seismic to well tie process as well as picking of horizons throughout the section. Time and depth structural maps were generated. Geostatistical simulation such as the sequential Gaussian stimulation and sequential indicator stimulation were carried out to provide equiprobable representations of the reservoirs, and the distribution of reservoir properties within the geological cells. The modeled reservoir properties resulted in an improved description of reservoir distribution and inter connectivity. The analysis indicated the presence of hydrocarbon in the reservoirs. There is also a fault assisted closure on the structural map which is of interest in exploration. A fluid distribution plot and map of the field were also obtained. The modeled properties gave an average porosity of 24%, average water saturation ranging from 12%-24% and moderate net-gross. The volumetric calculation of the reservoir gives a STOIIP ranging from 37.53 MMbbl-43.03 MMbbl. The result showed high hydrocarbon potential and a reservoir system whose performance is considered satisfactory for hydrocarbon production. The resulting models can also be used to predict the future performance of the reservoir.
{"title":"3-D Geostatistical Model and Volumetric Estimation of âÂÂDelâ Field, NigerDelta","authors":"Oluwadare Oa, Osunrinde Ot, Abe Sj, Ojo Bt","doi":"10.4172/2381-8719.1000291","DOIUrl":"https://doi.org/10.4172/2381-8719.1000291","url":null,"abstract":"There is an insatiable thirst for oil and gas consumption and increased production will be made possible only \u0000 through effective reservoir characterization and modeling. A suite of wire-line logs for four wells from ‘DEL’ oil field \u0000 together with 3D seismic data were analyzed for reservoir characterization of the field. Two reservoirs were identified \u0000 using the resistivity log. A synthetic seismogram was generated in order to perform seismic to well tie process as \u0000 well as picking of horizons throughout the section. Time and depth structural maps were generated. Geostatistical \u0000 simulation such as the sequential Gaussian stimulation and sequential indicator stimulation were carried out to provide \u0000 equiprobable representations of the reservoirs, and the distribution of reservoir properties within the geological cells. \u0000 The modeled reservoir properties resulted in an improved description of reservoir distribution and inter connectivity. \u0000 The analysis indicated the presence of hydrocarbon in the reservoirs. There is also a fault assisted closure on the \u0000 structural map which is of interest in exploration. A fluid distribution plot and map of the field were also obtained. The \u0000 modeled properties gave an average porosity of 24%, average water saturation ranging from 12%-24% and moderate \u0000 net-gross. The volumetric calculation of the reservoir gives a STOIIP ranging from 37.53 MMbbl-43.03 MMbbl. The \u0000 result showed high hydrocarbon potential and a reservoir system whose performance is considered satisfactory for \u0000 hydrocarbon production. The resulting models can also be used to predict the future performance of the reservoir.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"33 1","pages":"1-10"},"PeriodicalIF":0.0,"publicationDate":"2017-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73370305","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}
Pub Date : 2017-04-26DOI: 10.4172/2381-8719.1000288
Jena Pr, Mishra Pk
This study presents Optical, Microstructural, EPMA and X-ray tomography studies of the chromium-containing Beryl samples of Bangiriposi, Mayurbhanj district of Odisha. The detailed microscopic studies followed by EDAX analysis of different phases revealed the presence of beryllium aluminium silicate as the major matrix with yttrium silicate, Apatite, Albite, Quartz, Zircon, Cordierite and Ferichromite as minor inclusions. Micro-Raman data of the polished surface established the presence of gaseous (CO2, CH4), Water, and other Minerals. Few rare earth (lanthanides) elements such as Ce, Nd, Gd, Y and Sc, along with other transitional elements such as Ti and Zr, Cs are found to be present in these beryl samples. The volume percentage of silicate, phosphate, and oxide, as well as gaseous inclusions, are determined by X-ray tomographic study and are found to be 24%, 3.122% and 6.717% respectively.
{"title":"Microstructural, Raman, EPMA and X-ray Tomographic Study of the Odisha's Beryl (Emerald) Sample","authors":"Jena Pr, Mishra Pk","doi":"10.4172/2381-8719.1000288","DOIUrl":"https://doi.org/10.4172/2381-8719.1000288","url":null,"abstract":"This study presents Optical, Microstructural, EPMA and X-ray tomography studies of the chromium-containing Beryl samples of Bangiriposi, Mayurbhanj district of Odisha. The detailed microscopic studies followed by EDAX analysis of different phases revealed the presence of beryllium aluminium silicate as the major matrix with yttrium silicate, Apatite, Albite, Quartz, Zircon, Cordierite and Ferichromite as minor inclusions. Micro-Raman data of the polished surface established the presence of gaseous (CO2, CH4), Water, and other Minerals. Few rare earth (lanthanides) elements such as Ce, Nd, Gd, Y and Sc, along with other transitional elements such as Ti and Zr, Cs are found to be present in these beryl samples. The volume percentage of silicate, phosphate, and oxide, as well as gaseous inclusions, are determined by X-ray tomographic study and are found to be 24%, 3.122% and 6.717% respectively.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"103 1","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2017-04-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75688722","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}
Pub Date : 2017-04-08DOI: 10.4172/2381-8719.1000301
Robert Bassey, Peter O. Odong
Results of aeromagnetic data interpretation of Ilesha SW, Nigeria are presented here. The geology of Ilesha which is Precambrian falls under the basement complex of Nigeria. Depths to source rocks in this area are expected to be shallow. The results obtained revealed the presence of rocks such as amphibolites, quartz and schist which are the common rock types present in the study area. An aeromagnetic map of scale 1:50,000 was hand digitized, while forward and inverse modeling was achieved via the use of Potent, version 4.10.02. The field data were qualitatively and quantitatively interpreted and results showed NE-SW trending of the fault zone in the study area and anomalous bodies whose total magnetic intensity ranges from a minimum negative peak value of -625.5 nT to a maximum positive peak value of 179.43 nT. The maximum depth to top of the magnetic source body obtained is 34.2 m and minimum depth is 0.5 m. The results obtained indicate shallow depths to magnetic anomalies, as expected in most areas of the basement complex of Nigeria.
{"title":"Forward and Inverse Modeling of Hand Digitized Aeromagnetic Data from Ilesha South West, Nigeria","authors":"Robert Bassey, Peter O. Odong","doi":"10.4172/2381-8719.1000301","DOIUrl":"https://doi.org/10.4172/2381-8719.1000301","url":null,"abstract":"Results of aeromagnetic data interpretation of Ilesha SW, Nigeria are presented here. The geology of Ilesha which is Precambrian falls under the basement complex of Nigeria. Depths to source rocks in this area are expected to be shallow. The results obtained revealed the presence of rocks such as amphibolites, quartz and schist which are the common rock types present in the study area. An aeromagnetic map of scale 1:50,000 was hand digitized, while forward and inverse modeling was achieved via the use of Potent, version 4.10.02. The field data were qualitatively and quantitatively interpreted and results showed NE-SW trending of the fault zone in the study area and anomalous bodies whose total magnetic intensity ranges from a minimum negative peak value of -625.5 nT to a maximum positive peak value of 179.43 nT. The maximum depth to top of the magnetic source body obtained is 34.2 m and minimum depth is 0.5 m. The results obtained indicate shallow depths to magnetic anomalies, as expected in most areas of the basement complex of Nigeria.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"12 1","pages":"1-5"},"PeriodicalIF":0.0,"publicationDate":"2017-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84790071","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}
Pub Date : 2017-03-23DOI: 10.4172/2381-8719.1000285
Epuh Ee, Joshua Eo
Basement depth in the Gongola basin is found to be much deeper than previously supposed. Gravity modelling of the upper Benue Trough, Nigeria revealed thick sedimentation with maximum values within the range 5.2 km-7.0 km. This is in contrast to the average value of 5.0 km suggested by earlier studies. Gravity modelling across the basin was carried out to determine the basement depth using the second vertical derivative as input anomaly profile. The seismic modelling process in this research involves the determination of the distribution of seismic velocity using the: depth-normalized velocity iteration technique, check shot and sonic log curves. The integrated depth algorithm (IDA) iterative process was adopted in the determination of the interval and depth normalized interval velocities to adequately address the depth conversion for the determination of the lithology of the basin. The localized nature of the interpreted velocity data were extrapolated away from and interpolated between acquisition location using the areal coverage provided by gravity and seismic data. The interpretation involves the integration of the seismic reflection profiles, well logs and potential field data to establish a model of the sedimentary thicknesses and seismic velocities throughout the basin. The Basement depth on the north east of the basin is 7.0 km, southeast is 5.2 km whilst the northwest and southwest ranges between 0.5 km and 1.0 km respectively. The basement depths obtained from the gravity model was compared with that obtained from reflection seismic observation from the study area and the relative error percent were 1.37% and 0.46% respectively. The Precambrian basement depth normalized interval velocities ranges between 6.2 km/s and 6.4 km/s respectively. The qualitative interpretation of the second vertical derivative shows that the rift architecture/geometry is controlled by high angle faults and extended graben structures that form the major depocenters that are predominant in the upper Benue rift system. The grabens, half grabens, faults and deep sedimentation interpreted from the seismic reflection data are hydrocarbon related structural features. Consequently, the potentially hydrocarbon (gas) rich Yolde/Bima (Cenomanian-Albian) stratigraphic formations at depth between 2.1 km and 2.7 km and the depth normalized interval velocity varies from 2.9 km/s to 3.3 km/s and it occurs within the southeast zone of the basin.
{"title":"Basement Depth and Sedimentary Velocity Structure in Gongola Basin","authors":"Epuh Ee, Joshua Eo","doi":"10.4172/2381-8719.1000285","DOIUrl":"https://doi.org/10.4172/2381-8719.1000285","url":null,"abstract":"Basement depth in the Gongola basin is found to be much deeper than previously supposed. Gravity modelling of \u0000 the upper Benue Trough, Nigeria revealed thick sedimentation with maximum values within the range 5.2 km-7.0 \u0000 km. This is in contrast to the average value of 5.0 km suggested by earlier studies. Gravity modelling across the \u0000 basin was carried out to determine the basement depth using the second vertical derivative as input anomaly profile. \u0000 The seismic modelling process in this research involves the determination of the distribution of seismic velocity using \u0000 the: depth-normalized velocity iteration technique, check shot and sonic log curves. The integrated depth algorithm \u0000 (IDA) iterative process was adopted in the determination of the interval and depth normalized interval velocities to \u0000 adequately address the depth conversion for the determination of the lithology of the basin. The localized nature of \u0000 the interpreted velocity data were extrapolated away from and interpolated between acquisition location using the \u0000 areal coverage provided by gravity and seismic data. The interpretation involves the integration of the seismic \u0000 reflection profiles, well logs and potential field data to establish a model of the sedimentary thicknesses and seismic \u0000 velocities throughout the basin. The Basement depth on the north east of the basin is 7.0 km, southeast is 5.2 km \u0000 whilst the northwest and southwest ranges between 0.5 km and 1.0 km respectively. The basement depths obtained \u0000 from the gravity model was compared with that obtained from reflection seismic observation from the study area and \u0000 the relative error percent were 1.37% and 0.46% respectively. The Precambrian basement depth normalized interval \u0000 velocities ranges between 6.2 km/s and 6.4 km/s respectively. The qualitative interpretation of the second vertical \u0000 derivative shows that the rift architecture/geometry is controlled by high angle faults and extended graben structures \u0000 that form the major depocenters that are predominant in the upper Benue rift system. The grabens, half grabens, \u0000 faults and deep sedimentation interpreted from the seismic reflection data are hydrocarbon related structural \u0000 features. Consequently, the potentially hydrocarbon (gas) rich Yolde/Bima (Cenomanian-Albian) stratigraphic \u0000 formations at depth between 2.1 km and 2.7 km and the depth normalized interval velocity varies from 2.9 km/s to \u0000 3.3 km/s and it occurs within the southeast zone of the basin.","PeriodicalId":80381,"journal":{"name":"AGSO journal of Australian geology & geophysics","volume":"46 1","pages":"1-9"},"PeriodicalIF":0.0,"publicationDate":"2017-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77218801","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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