The geology of the Olode area, south-western Nigeria was investigatedpetrographically and geochemically in order to elucidate the mineralisationpotential of the rock units in the area. The area under study is generall...The geology of the Olode area, south-western Nigeria was investigatedpetrographically and geochemically in order to elucidate the mineralisationpotential of the rock units in the area. The area under study is generallychange to underlained by granite gneiss, mica schist and pegmatites.Petrographical studies indicated prevalence of anhedral quartz (30 - 50%),plagioclase (14 - 20%), orthoclase (12 - 15%), muscovite (11 - 15%),tourmaline (6 - 10) and other minerals (8 - 11%) for the pegmatite. Thehigh value of SiO2 and Al2O3 is consistent with the petrographical study.High values and wide range in Ba (34 - 737 ppm) and Zr (3.8 - 132.6 ppm)strongly support a mixture of igneous and sedimentary. The bivariant plotsof Rb vs K/Rb, Zn vs K/Rb and Th vs K/Rb indicated a partial series offractionation, suggesting that the pegmatites are of rare element classeswhile granite gneiss and mica schist belong to the barren muscovite andrare element classes. This was supported by high ratios of K/Cs and K/Babut low Th/U values indicating distinctively low rare metal mineralization.The plot of Na2O/Al2O3 vs K2O/Al2O3 revealed an igneous precursor for allthe rock units. The negative Eu anomalies especially in the pegmatitic rockunit indicates fractionation and point toward a late metasomatic effect andtheir relatively weak negative Ce anomalies, also suggest their rare metalmineralization. The pegmatites, granite gneiss and mica schist of Olodearea considered as barren as all the samples plotted below the Gordiyenkosand Beus’ line of mineralization.展开更多
In order to investigate the source,contamination,and risk of heavy metals such as Pb,Zn,Cu,Ni,Co,Fe,Mn,and Cr,twelve(12)stream sediments and ten(10)rock samples were collected from pegmatite mining sites at Olode and ...In order to investigate the source,contamination,and risk of heavy metals such as Pb,Zn,Cu,Ni,Co,Fe,Mn,and Cr,twelve(12)stream sediments and ten(10)rock samples were collected from pegmatite mining sites at Olode and its environs inside Ibadan,Southwestern Nigeria.The average values and order of abundance obtained followed the pattern:Mn(595.09)>Ba(80)>Cr(50.82)>V(45.09)>Zn(29.73)>Cu(13.82)>Co(13.82)>Sr(10.46)>Ni(9.73)>Pb(9.09)>Fe(1.59).These were greater than the background values,indicating that mining has a negative impact on the study area,as indicated by the high coefficient of variation and correlation values(>0.6)for Copper-Lead(0.929),Copper-Vanadium(0.970),Copper-Chromium(0.815),Lead-Vanadium(0.884),and others.On the basis of the enrichment factor(EF),the Olode sediments show extremely high enrichment for Mn and Ba in the research region.Cu and Ni are most likely to blame for the elevated contamination levels,according to CF values.The degree of contamination(CD),pollution load index(PLI),pollution index(PI),and modified pollution index(MPI)all revealed high levels of contamination in all stream sediment samples,whereas Igeo shows that the Olode stream sediments are“practically uncontaminated to extremely contaminated by Ni,Co,and Mn”.Ni and Cu are the major regulating factors that are most likely causing the possible Eri.As a result,these findings give important information for conducting appropriate ecological management research.展开更多
文摘The geology of the Olode area, south-western Nigeria was investigatedpetrographically and geochemically in order to elucidate the mineralisationpotential of the rock units in the area. The area under study is generallychange to underlained by granite gneiss, mica schist and pegmatites.Petrographical studies indicated prevalence of anhedral quartz (30 - 50%),plagioclase (14 - 20%), orthoclase (12 - 15%), muscovite (11 - 15%),tourmaline (6 - 10) and other minerals (8 - 11%) for the pegmatite. Thehigh value of SiO2 and Al2O3 is consistent with the petrographical study.High values and wide range in Ba (34 - 737 ppm) and Zr (3.8 - 132.6 ppm)strongly support a mixture of igneous and sedimentary. The bivariant plotsof Rb vs K/Rb, Zn vs K/Rb and Th vs K/Rb indicated a partial series offractionation, suggesting that the pegmatites are of rare element classeswhile granite gneiss and mica schist belong to the barren muscovite andrare element classes. This was supported by high ratios of K/Cs and K/Babut low Th/U values indicating distinctively low rare metal mineralization.The plot of Na2O/Al2O3 vs K2O/Al2O3 revealed an igneous precursor for allthe rock units. The negative Eu anomalies especially in the pegmatitic rockunit indicates fractionation and point toward a late metasomatic effect andtheir relatively weak negative Ce anomalies, also suggest their rare metalmineralization. The pegmatites, granite gneiss and mica schist of Olodearea considered as barren as all the samples plotted below the Gordiyenkosand Beus’ line of mineralization.
文摘In order to investigate the source,contamination,and risk of heavy metals such as Pb,Zn,Cu,Ni,Co,Fe,Mn,and Cr,twelve(12)stream sediments and ten(10)rock samples were collected from pegmatite mining sites at Olode and its environs inside Ibadan,Southwestern Nigeria.The average values and order of abundance obtained followed the pattern:Mn(595.09)>Ba(80)>Cr(50.82)>V(45.09)>Zn(29.73)>Cu(13.82)>Co(13.82)>Sr(10.46)>Ni(9.73)>Pb(9.09)>Fe(1.59).These were greater than the background values,indicating that mining has a negative impact on the study area,as indicated by the high coefficient of variation and correlation values(>0.6)for Copper-Lead(0.929),Copper-Vanadium(0.970),Copper-Chromium(0.815),Lead-Vanadium(0.884),and others.On the basis of the enrichment factor(EF),the Olode sediments show extremely high enrichment for Mn and Ba in the research region.Cu and Ni are most likely to blame for the elevated contamination levels,according to CF values.The degree of contamination(CD),pollution load index(PLI),pollution index(PI),and modified pollution index(MPI)all revealed high levels of contamination in all stream sediment samples,whereas Igeo shows that the Olode stream sediments are“practically uncontaminated to extremely contaminated by Ni,Co,and Mn”.Ni and Cu are the major regulating factors that are most likely causing the possible Eri.As a result,these findings give important information for conducting appropriate ecological management research.
