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A Co.parative Assessment o. the Physico.Chemical and Micro.ial Trends in Njaba River, Niger Delta Basin, So.theastern Nigeria

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Jo.rnal o. Water Reso.rce and Pro.ectio. 2011年第9期3卷 686-693页

作者： Co.mas Ahamefula Ahiarakwem samuel o. onyekuru 不详

Water quality mo.ito.ing at five (5) different gauge statio.s o. the co.rse o. Njaba River was undertaken to.understand the variability o. the physico.chemical and micro.ial co.tents o. the river water within a specified perio. o. time (2003-2008). Co.lected water samples were analyzed using Ato.ic Abso.ptio. Spectro.ho.o.eter (AAS), Digital Meters and Standard Plate Co.nts. Results o. the analyses indicated that average pH, electrical co.ductivity and the To.al Disso.ved So.ids (TDS) o. the Njaba River in 2003 were 6.3, 22 μS/cm and 13.5 mg/l, respectively. Mean values in 2008 fo. the same parameters were 6.4, 24.4μS/cm and 14.7 mg/l, respectively. Mean co.centratio.s o. analyzed catio.s (Ca2+, Mg2+, Na+ and K+) in 2003 were 4.10, 0.15, 5.00 and 1.20 mg/l, respectively, and that o.tained fo. same parameters in 2008 were 4.40, 0.18, 6.40 and 1.30 mg/l, respectively. The mean co.centratio.s o. analyzed anio.s (HCo. - , So. 2-, Cl- and No. - ) in 2003 were 20.0, 4.0, 1.30 and 0.20 mg/l, respectively and in 2008 the mean co.centratio.s were 24.5, 4.20, 1.60 and 0.22 mg/l, respectively. Characterizatio. o. the river water fo.lo.ed the trend: Na+ > Ca2+ > K+ > Mg2+ (fo. the catio.s) and HCo. - > So. 2- > Cl- > No. - (fo. anio.s), sho.ing the Njaba River is NaHCo. water. Mean co.centratio.s o. Disso.ved o.ygen (Do. and Bio.hemical o.ygen Demand (Bo.) o. the river water were 7.2 and 2.2 mg/l, respectively in 2003, and 8.0 and 4.0 mg/l respectively, in 2008. To.al Co.ifo.m Co.nts o. the river water in 2003 ranged fro. 70 - 90 cfu/100ml with a mean value o. 80 cfu/100ml, while the co.nts in 2008 ranged fro. 100 - 120 cfu/100ml with a mean value o. 110 cfu/100 ml. Calculated Po.lutio. Index (PI) slightly increased fro. 0.72 in 2003 to.0.73 in 2008. These water quality determinants revealed gradual rise in the co.centratio.s o. the respective physico.chemical parameters and bacterio.o.ical co.stituents o. the Njaba River water. So.ium Adso.ptio. Ratio.(SAR) o. 1.37 in 2003 and

关键词： Co.centratio. Variability Characterizatio. Water Quality Watershed Po.lutio.

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Land Capability Index Mapping fo. Waste Dispo.al Landuse o.tio. Using Geo.raphic Info.matio. System (GIS) in Enugu Area, So.th Eastern Nigeria

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Jo.rnal o. Geo.raphic Info.matio. System 2012年第5期4卷 444-461页

作者： A. A. o.unkwo.samuel o. onyekuru G. I. Nwankwo. Department o. Geo.o.y Federal University of Technology Owerri Owerri Nigeria

The pro.ected 300% gro.th rate in the po.ulatio. o. Enugu area and its enviro.s by the year 2020 and the expected increase in waste generatio. necessitated the need to.map o.t areas fo. waste dispo.al fo. future utilizatio. and as a pro.ective strategy fo. the enviro.ment in Enugu area. Land capability index mapping using Geo.raphic Info.matio. System (GIS) is o.e o. the appro.riate to.ls required fo. so.ving this pro.lem. A to.al o. 12 landuse determinants were selected as thematic data layers, and as basic facto.s influencing the cho.ce o. waste dispo.al landuse o.tio. in the area. The themes (thematic maps) generated fro. field/labo.ato.y measurements and fro. literature, include slo.e, water table, surface and subsurface water co.ditio.s, elevatio., geo.o.y, so.l, drainage and geo.structural stability (fault, ero.io., landslide and flo.ding) maps. The maps were scanned, digitized, geo.eferenced, and po.ygo.ized using auto.ard drawing capabilities to.co.vert them into.vecto. fo.mat and later expo.ted to.arc view so.tware fo. analysis. The final pro.essing using o.erlay mo.el builder yields layers that display areas o. preferred waste dispo.al sites in a map fo.m, which generally sho.s areas o. varying suitability (suitable, mo.erately (lo.) suitable and unsuitable). The waste dispo.al map o. Enugu area sho.s that blo.ks1 (o.eagu area) and 3 (Ebe/Nsude areas) represent suitable and unsuitable areas, respectively, while blo.k 2 (Ngwo.area) has lo. suitability fo. waste dispo.al.

关键词： Landuse Thematic Maps Waste Dispo.al Land Capability

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Dispersal Patterns o. the Late Cretaceo.s to.Early-Tertiary Sediments in the So.thern Anambra Basin, So.theastern Nigeria

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Internatio.al Jo.rnal o. Geo.ciences 2013年第3期4卷 588-604页

作者： samuel o. onyekuru Chukwuma J. Iwuagwu Go.win I. Nwankwo. Nathaniel N. o.u Cyril E. Ukao.u Department o. Geo.cience Federal University of Technology Owerri Nigeria Department o. Geo.cience Federal University of Technology Owerri Nigeria First Explo.atio. and Petro.eum Develo.ment Co.pany Limited Ikoyi Lagos Nigeria

The dispersal patterns o. the Late Cretaceo.s to.Early Tertiary sediments in so.thern Anambra Basin were studied to.delineate spatial facies distributio.s fo. impro.ed mapping and hydro.arbo. pro.pectivity. Seven litho.acies distinguished fro. eleven o.tcro. sectio.s aided the interpretatio. o. depo.itio.al enviro.ments fo. the different depo.itio.al units. Interpreted paleo.nviro.ments ranged fro. estuarine/lago.nal to.tidal delta and shallo. marine depo.itio.al enviro.ments. Sequence stratigraphic interpretatio. o. the depo.its using vertical relatio.ships between the delineated facies and fo.aminiferal and palyno.acies assemblages and the interpreted enviro.mental setting identified two.co.plete sequences (SEQ-1 and -2) and two.inco.plete sequences (SEQ-3 and -4) in the study area. The sequiences are envelo.ed by three Type-1 Sequence Bo.ndaries (SB), two.Transgressive Surfaces o. Ero.io. (TSE) and fo.r Maximum Flo.ding Surfaces (MFS). The identified surfaces were used to.delineate fo.matio. bo.ndaries and as such wo.ld assist in the impro.ed mapping o. the Anambra Basin and adjo.ning depo.enters. The massive sand units o. the Highstand and Transgressive Systems Tracts co.stitute go.d (po.ential) reservo.rs, while the transgressive shales wo.ld co.stitute seals fo. po.ential traps in the study area. The delineatio. o. these petro.eum system elements, especially tho.e asso.iated with the Transgressive and Highstand Systems Tracts has co.ferred great hydro.arbo. pro.pectivity po.ential o. the sedimentary sequences in the Basin. The absence o. deep marine and slo.e co.plexes o. the Lo.stand Systems Tract (LST) in the interpreted sequences is indicative that the study area is the up-dip sectio. o. the Anambra Basin.

关键词： Dispersal Patterns Fo.matio. Sequence Bo.ndary Facies Spatial Co.plexes Ero.io.

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Characterizatio. o. the Upper Cretaceo.s Sediments in the Ikpankwu-Ihube Axis, o.igwe, So.theastern Nigeria

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Internatio.al Jo.rnal o. Geo.ciences 2019年第6期10卷 724-744页

作者： samuel o.echukwu onyekuru Chukwuma Julian Iwuagwu Jo. o.enyi Kelechi Denis o.ara Ukamaka Nwachiani Nwigbo Department o. Geo.o.y Federal University of Technology Owerri Nigeria

Detailed characterizatio. o. the o.tcro.ping sediments in the Ikpankwu and Ihube axis was undertaken to.validate litho.tratigraphic bo.ndaries and no.enclatures which had stirred up debates amo.gst scho.ars in recent times. Sto.hastic metho. established do.inant facies asso.iatio.s and preferred stacking patterns, which were used to.interpret enviro.ments o. depo.itio. (Eo.s), while fo.aminiferal and palyno.o.ical analyses fingerprinted bo.h paleo.depths and age o. the sediments. The results established the do.inance o. similar litho.acies at the basal parts o. bo.h sectio.s indicating mappable geo.o.ical units and members o. the same litho.tratigraphic unit. The basal litho.acies are succeeded up sectio., ho.ever, by different litho.o.ical units in bo.h the KM 75 and Ikpankwu sectio.s. Interpretatio.s o. Eo.s using litho.acies successio.s predicted fluvial to.tidally-influenced shallo. marine depo.its, which are enviro.ments in clo.e affinity with each o.her. Interpretatio.s using abundance and diversity o. micro.fauna suppo.ted no.-marine (co.stal-deltaic) to.middle neritic paleo.water depths also. typical o. marginal to.shallo. marine Eo.s. Reco.ered fo.aminiferal assemblages in the shale samples fro. the upper parts o. bo.h sectio.s, ho.ever, depicted depo.its o. Nsukka Fo.matio. despite variatio.s o.served in litho.acies assemblages because the identified Haplo.hragmo.des species that po.ulate the upper units had been used to.define the Late Maastrichtian-Paleo.ene age. Sediments at the basal parts with mappable litho.o.ical units at bo.h sectio.s were rather po.ulated by species that co.no.e the Campanian-Maastrichtian age when the Mamu Fo.matio. sediments were depo.ited. Palyno.o.phs reco.ered fro. bo.h the basal and upper sectio.s also.suggested Campanian-Maastrichtian and Late Maastrichtian-Paleo.ene age, indicative o. Mamu and Nsukka Fo.matio. sediments, respectively.

关键词： Assemblages Bio.acies Characterizatio. Enviro.ment Fo.matio. Litho.acies

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Sequence Stratigraphic Analysis o. “XB Field”, Central Swamp Depo.elt, Niger Delta Basin, So.thern Nigeria

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Internatio.al Jo.rnal o. Geo.ciences 2012年第1期3卷 237-257页

作者： samuel o.echukwu onyekuru Emmanuel Chukwudi Ibelegbu Julian Chukwuma Iwuagwu Akan Go.frey Essien Casmir Zanders Akao.isa Department o. Geo.o.y Federal University of Technology Owerri Nigeria

Well lo.s and bio.tratigraphic data fro. six wells in the “XB Field”, central Swamp Depo.elt, Niger Delta were integrated to.carry o.t a sequence stratigraphic analysis o. depo.itio.al systems in the field. The analysis revealed fo.r 3rd o.der depo.itio.al sequences (SEQ1 to.4) bo.nded by three ero.io.al unco.fo.mities interpreted as Sequence Bo.ndaries (SB1 to.3). Transgressive Surfaces o. Ero.io. (TSE1 to.3) that mark the o.set o. marine flo.ding and turnaro.nds fro. pro.radatio.al facies to.retro.radatio.al facies during sequence build-up were delineated. Three 3rd o.der Maximum Flo.ding Surfaces (MFS1, MFS2 and MFS3) characterized by marker shales, high faunal abundance and diversity were also.delineated and dated 15.9, 17.4 and 19.4 Ma, respectively. The delineated sequences co.prised Lo.stand Systems Tracts (pro.radatio.al packages), Transgressive Systems Tracts (retro.radatio.al packages) and Highstand Systems Tracts (aggradatio.al packages), which reflect depo.itio.al systems depo.ited during different phases o. base level changes. The Lo.stand Systems Tract (LST) co.sists o. Basin Flo.r Fans (BFF), Slo.e Fans and Channel Sands depo.ited when sea level was lo. and acco.mo.atio. space lo.er than rate o. sediment influx. Transgressive Systems Tract (TST) co.sists o. retro.radatio.al marine shales depo.ited during high relative sea levels and when acco.mo.atio. space was higher than rate o. sediment influx. Highstand Systems Tracts (HST) co.sisted o. sho.eface sands displaying mo.tly aggradatio.al to.pro.radatio.al stacking patterns. The sands o. LST and HST sho. go.d reservo.r qualities while the shales o. the TSTs co.ld fo.m po.ential reservo.r seals. The abo.e reco.nized sequences, were depo.ited within the Neritic to.Bathyal paleo.nviro.ments and are dated mid-Mio.ene (15.9 - 20.4 Ma) in age.

关键词： Sequence Stratigraphy Unco.fo.mities Pro.radatio. Retro.radatio.al Aggradatio.al Paleo.nviro.ments and Reservo.r

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Petro.o.y and Geo.hemistry o. Basement Co.plex Ro.ks in o.o.-Ita Area, o.an Massif, So.theastern Nigeria

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Internatio.al Jo.rnal o. Geo.ciences 2014年第4期5卷 394-407页

作者： Kelechi Denis o.ara Yo.ng E. o.io.a samuel o.echukwu onyekuru Chikwendu o.ereke Sabinus Ikechukwu Ibeneme Department o. Geo.ciences Federal University of Technology Owerri Nigeria

The determinatio. o. the mineralo.ical co.po.itio. o. ro.ks that underlie o.o.-Ita area, in o.an Massif became necessary fo. the interpretatio. o. the petro.enesis and pro.o.iths o. ro.ks in the area. Twelve representative ro.k samples were selected fo. thin sectio. petro.raphy and bulk ro.k geo.hemical analysis. The results reveal that the do.inant intrusive ro.ks in o.o.-Ita area are pegmatites, quartz veins and do.erites emplaced within gneisses, schists and phyllites ho.t ro.ks. The quartz veins and pegmatites are leuco.ratic co.sisting predo.inantly o. quartz, plagio.lase and subo.dinate amo.nt o. Musco.ites. The do.erite is dark grey, fine to.medium grained and texturally o.hitic and co.sists do.inantly o. pyro.enes, o.ivine and o.aques. Three varieties o. gneisses were reco.nized: feldspathic, banded and bio.ite gneisses. The gneisses, schists, and phyllites are do.inated by Sio. in the range o. (60% - 75%). The ro.ks exhibit higher mo.ecular co.centratio. {Al2o. > (Cao.+ Na2o.+ K2o.}, high alkali co.centratio. with Na2o.> K2o. high Al2o. to.alkali ratio. and lo. Tio., Cao.and Mgo.co.centratio.s. These distributio. trends suggest a co.pensatio. fo. the high silica and alumina co.centratio.s and suppo.t a granitic pro.o.ith fo. the pegmatites and their ho.t gneisses and schists. The do.erites and amphibo.ites are impo.erished in Sio., but relatively enriched in lime and alkali o.ides. Plo.s in the AFM, Tio.-K2o.P2o. and Na2o.Al2o.-K2o.Al2o. diagrams sho. that the pegmatite was derived fro. calc-alkaline magmatic so.rce, while the do.erite was derived fro. tho.eiitic basalt magma.

关键词： o.o.-Ita o.an Massif Petro.o.y Geo.hemistry Petro.enesis Pro.o.ith Tecto.ics

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