Papers by Emmanuel Igonor
Global Journal of Pure and Applied Sciences, 2011
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'... more The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist and granodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against a...
The “Uwet Granodiorite” is a term referring to PanAfrican granitoids (granodiorites) occurring in... more The “Uwet Granodiorite” is a term referring to PanAfrican granitoids (granodiorites) occurring in the Uwet area – Oban massif, SE Nigeria (8 o 00’ – 8 30’E and 5 o 00’ – 5 o 30’N). These rocks were emplaced by magmatic stoping and assimilation, and possible products of the mixing of more than one magma series and or con tami ation. Several authors have proposed suggestions on the pr ocesses and timing of megacrysts formation in grani toids. Structural, petrographical and chemical studies fro m this work strongly favour a magmatic/phenocrystic origin for the K-feldspar megacrysts in Uwet granodiorite. The se vidences also show that the phenocrysts were fo rmed at liquidus temperature in the presence of abundant li quid. These results agree with similar studies from other parts of the world.
About 40 pegmatites exposures hosted by the metamorphic (schists and gneisses) and igneous rock u... more About 40 pegmatites exposures hosted by the metamorphic (schists and gneisses) and igneous rock unit (porphyritic and non-porphyritic granodiorites), which characterize the area were investigated and representative samples analyzed for geochemical characterization. Macroscopic study shows large crystals of schorls, albite, plagioclase and quartz. Geochemical analysis carried out at the Activation Laboratory – Canada, shows the pegmatites to be peraluminous from estimated Aluminium Saturation Index (ASI) which is greater than one (1). Variation plot of Na 2 O + K 2 O vs. SiO 2 classifies the rocks as alkali to sub-alkalic types. SiO 2 and Al 2 O 3 values which averages at 67.74 % and 14.49 % respectively are lower when compared to pegmatites from similar fields in other parts of the country. But they are richer in Fe 2 O 3 with an average value of 4.16 %. Trace elements such as Ba, Sr, Zr, Rb, Ta, and Nb have average concentrations of (71.15, 27.50, 16.61, 344.70, 18.14, and 71.70) p...
Advances in Applied Science Research, 2012
Megacrysts of feldspar occur randomly and abundantly in pegmatite veins hosted by gneisses in the... more Megacrysts of feldspar occur randomly and abundantly in pegmatite veins hosted by gneisses in the Oban massif (SE Nigeria). Earlier work has shown that these megacrysts are k-feldspars and magmatic products, formed at liquidus temperature in the presence of enough liquid that allowed the crystals to flow. Megacryst size, frequency and other physical characteristics were used to unravel their nucleation and crystal growth history. Analyses of over 400 megacrysts present in the pegmatite veins, showed that: (a) larger megacrysts occur closer to the middle of the veins, while smaller ones occur near the vein wall; (b) the smaller grains have larger angle difference between their long axes and the vein wall, while the longer grains have smaller angle difference; and (c) the wider veins contain larger-size but fewer grains, while the narrower veins contain smaller but more grains. It is deduced that the largesize megacrysts, which are also fewer in frequency, are most likely crystals tha...
British Journal of Applied Science & Technology, 2013
The aim & objective of the study is to identify the Carriage rate of Streptococcus mutans from fi... more The aim & objective of the study is to identify the Carriage rate of Streptococcus mutans from five anatomical surfaces of oral cavity of Type II Diabetes Mellitus and Non Diabetic population & to compare carriage rate Streptococcus mutans of Type II against Non Diabetic population. Swabs were collected from five different anatomical sites of the oral cavity from Type II and Non Diabetic patients of 30 each. Samples were confirmed for the species and then inoculated in Mitis Salivaris Agar to assess the Frequency of isolation and Colony Forming Units (CFU) of Streptococcus mutans. Observation of the study revealed that the Frequency of Isolation and Colony Forming Units were high in patients with Type II Diabetes Mellitus when compared to that of Non Diabetes Mellitus subjects. Type II Diabetes Mellitus, Streptococcus mutans, Colony Forming Units, Carriage rate, Oral Microbial Flora.
Journal of Geography, Environment and Earth Science International, 2016
This study aimed to determine the major elemental oxides in the exposed rock types of the study a... more This study aimed to determine the major elemental oxides in the exposed rock types of the study area, classify these rocks on this basis and establish the relationships between the various elemental constituents and hence predict the mode of origin of the rocks. The study area falls within the southwestern part of the reactivated Basement Complex of Nigeria. Field work to collect samples lasted about 21 days. About 13 fresh rock samples from the igneous suite, which range from fine to coarse grains, were collected. Thin sections were cut and petrographic studies carried out, also geochemical analysis of the samples was done at the Activation Laboratories, Ontario, Canada. Field investigation clearly revealed two distinct suite of rocks, which characterises the study area. These are the migmatite gneiss suite and the igneous suite. The migmatite gneiss suite, which consists of the migmatite gneiss and the banded gneiss, is the basement rock of the terrain. While the igneous suite, which is mainly the rocks of the older granitoids, intrude the older Original Research Article
Stream sediments of Obudu Plateau were investigated with a view to elucidating their geochemical ... more Stream sediments of Obudu Plateau were investigated with a view to elucidating their geochemical features, mineralization potentials and element concentrations. Stream sediment samples were collected from Southern Obudu Plateau area and analyzed for 22 elements, comprising major and trace elements, using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The data obtained were statistically treated. Ba, Sr, Nb, Co, Pb, Ta and Na show moderate to high concentrations, when compared with threshold values of these elements. The concentrations of these elements in sediments of Southern Obudu show low mineralization potentials of pegmatites of the Obudu Plateau. The elements in Obudu stream sediments show perfect, strong, moderate and weak correlations among themselves, indicative of variations in their mobility.
This study aimed to determine the major elemental oxides in the exposed rock types of the study a... more This study aimed to determine the major elemental oxides in the exposed rock types of the study area, classify these rocks on this basis and establish the relationships between the various elemental constituents and hence predict the mode of origin of the rocks. The study area falls within the southwestern part of the reactivated Basement Complex of Nigeria. Field work to collect samples lasted about 21 days. About 13 fresh rock samples from the igneous suite, which range from fine to coarse grains, were collected. Thin sections were cut and petrographic studies carried out, also geochemical analysis of the samples was done at the Activation Laboratories, Ontario, Canada. Field investigation clearly revealed two distinct suite of rocks, which characterises the study area. These are the migmatite gneiss suite and the igneous suite. The migmatite gneiss suite, which consists of the migmatite gneiss and the banded gneiss, is the basement rock of the terrain. While the igneous suite, which is mainly the rocks of the older granitoids, intrude the older Original Research Article
Pegmatites the world over have been known to generate lots of interest because they sometimes pla... more Pegmatites the world over have been known to generate lots of interest because they sometimes play host to abundance of economically valuable mineral deposits like gemstones and rare-metal ores of tantalum, niobium, wolfram, lithum and tungsten, which drive the present day economic revolution. But the pegmatite veins of Obudu massif have received little or no research or commercial attention. A detailed geologic mapping exercise spanning over 30days was undertaken to study the various lithological units of the area (Nigerian Topo-sheet Obudu 291SE), with special interest in the pegmatite veins as they occur in the area. From the field observation and analyses, the major lithological unit's in Obudu SE area are: gneisses, schist, amphibolites, charnockites, dolerite dykes, quartz veins, and pegmatite veins. Traceable pegmatite vein length ranges from less than 1m to over 80m; though the most frequently occurring vein length is between 6m – 8m. Pegmatite vein widths range from <1cm to over 7m. The pegmatite veins of Obudu SE favour high angle fractures i.e fractures which dip at angles >50 o. Over 200 strike measurements of the pegmatite veins show that more than 25% fall between 161 o – 180 o from north, which is the most preferred orientation. The pegmatites are mainly made up of quartz, feldspar and muscovite flakes but sometimes also contain gem mineralisation like amethyst, tourmaline, or aquamarine. Prospects for rare-earth mineralisation in the pegmatites of Obudu SE area look unpromising as they lack any visible occurrence of tantalite, niobium, lepidolite or any other rare-earth metal even though further geochemical analysis would be needed to ascertain this claim. INTRODUCTION Pegmatites are a variety of extremely coarse grained igneous rocks, which are somewhat chemically similar to and closely associated with granite. According to Read (1973) they are coarse-grained, quartz-feldspar rocks formed by the consolidation of the last portion of the magma. Typical mineral constituents of pegmatites are largely those of a typical acid intrusive rock and they are found to be distributed especially in old mountain chains, where igneous and metamorphic rocks prevail like the Obudu massif. Pegmatites the world over have been known to generate lots of interest both for academic concern as well as commercial intents. This interest stems from the fact that pegmatites sometimes play host to abundance of economically valuable mineral deposits like gemstones and rare-metal such as tantalum, niobium and tungsten and others which drive the present day technological revolution. Despite the huge interest in pegmatites both locally and internationally, the pegmatite veins of Obudu massif have received little or no academic or commercial interest.
Megacrysts of feldspar occur randomly and abundantly in pegmatite veins hosted by gneisses in the... more Megacrysts of feldspar occur randomly and abundantly in pegmatite veins hosted by gneisses in the Oban massif (SE Nigeria). Earlier work has shown that these megacrysts are k-feldspars and magmatic products, formed at liquidus temperature in the presence of enough liquid that allowed the crystals to flow. Megacryst size, frequency and other physical characteristics were used to unravel their nucleation and crystal growth history. Analyses of over 400 megacrysts present in the pegmatite veins, showed that: (a) larger megacrysts occur closer to the middle of the veins, while smaller ones occur near the vein wall; (b) the smaller grains have larger angle difference between their long axes and the vein wall, while the longer grains have smaller angle difference; and (c) the wider veins contain larger-size but fewer grains, while the narrower veins contain smaller but more grains. It is deduced that the large-size megacrysts, which are also fewer in frequency, are most likely crystals that nucleated and started growing during a small degree of temperature change (during the cooling of the magma melt). Under favourable conditions they grew to large sizes, while the more abundant and smaller-sized megacrysts nucleated and grew during a greater degree of temperature change. Since under such conditions nucleation and growth rates are high, with the crystals competing for solute particles, more abundant but smaller sizes of megacrysts were formed.
The " Uwet Granodiorite " is a term referring to Pan-African granitoids (granodiorites) occurring... more The " Uwet Granodiorite " is a term referring to Pan-African granitoids (granodiorites) occurring in the Uwet area – Oban massif, SE Nigeria (8 o 00' – 8 o 30'E and 5 o 00' – 5 o 30'N). These rocks were emplaced by magmatic stoping and assimilation, and possible products of the mixing of more than one magma series and or contamination. Several authors have proposed suggestions on the processes and timing of megacrysts formation in granitoids. Structural, petrographical and chemical studies from this work strongly favour a magmatic/phenocrystic origin for the K-feldspar megacrysts in Uwet granodiorite. These evidences also show that the phenocrysts were formed at liquidus temperature in the presence of abundant liquid. These results agree with similar studies from other parts of the world.
British Journal of Applied Science and Technology, Aug 27, 2013
Aims: It is the intention of the authors to through this paper; evaluate the current situations i... more Aims: It is the intention of the authors to through this paper; evaluate the current situations in Nigeria by highlighting the recent reforms in the solid minerals sector and how these reforms can help sustain viable mineral exploration and mining activities. This study aim at informing the investor in the solid mineral sector how these reforms promote good investment climate and ensure good Return on Investment. Methodology: We included results from international literature related to mining and investment (including World Bank and Fraser Institute publications), recent studies specific to the Nigerian context (including studies and activities carried out by the Nigerian Geological Survey Agency), interview data with key participants who represent global mining experts and, the author's personal experience in exploration activities specific to Nigeria. Results and Conclusion: Mineral resources occurrence in Nigeria or any country transcends political boundaries. But the industry involved in its exploration and exploitation, thrives well in an enabling environment like; favourable economic, legal, political and technological regimes. In order to compete with other countries/ mining destinations advanced in the exploration and mining of solid minerals and to woo
entreprenuership is all about solving problems with your aquired knowledge. entreprenuership in g... more entreprenuership is all about solving problems with your aquired knowledge. entreprenuership in geology is knowing about geological products and how to source and sell them for profit. this special quartz crystals are available from our mineral resources in stock to sell to all interested buyers from all over the world.
The Benue trough is Nigeria’s main, but not exclusive source of barite mineralisation. There are ... more The Benue trough is Nigeria’s main, but not exclusive source of barite mineralisation. There are at least ten barite fields in the trough, each containing swarms of veins or concordant stratiform minerals flats of hydrothermal origin. There are only two vein trends in the trough: the NW-SE trend, which tends to be orthogonal to the axis of the trough; and the N-S to NNE-SSW trend, which is younger than the former. Both vein sets are formed from ac tension joints reflecting different post-sedimentary deformation phases in the trough. The NW-SE veins are also more frequent than the N-S veins, almost in the ration of 2:1. Although 86 veins have been studied, not one was found oriented parallel to the axis of the trough, a good indication of structural control on mineral vein orientations. The dips of the veins tend to be high (>80o), a condition that favours manual mining. Veins tend to display a simple block profile and their widths vary from a few centimetres to as much as 6m, though the most frequently occurring widths are between 50cm and 1m. The implication of this is that BaSO4 concentrations in hydrothermal fluids in the trough were probably low during the Cretaceous period. In many veins, there is barite quality contrast between the top part and the lower portions. Higher quality barite tends to come from the lower portions. Hence it is expected that much of the low quality stigma associated with Nigerian barite from the trough would be relieved when mining gets down to good depths. For this reason, mining in those veins of low quality barite should proceed by vertical stripping.
Investment opportunities in the gemstones business in Nigeria
There are abundant and diverse Inv... more Investment opportunities in the gemstones business in Nigeria
There are abundant and diverse Investment opportunities in the nascent colored gemstones industry in Nigeria and these include: mining, trading, brokering deals, and processing.
Mining: Mining of coloured gemstones is widespread in the nation and is mainly carried out by Artisans and Small scale Miners (ASM). The artisanal miners are informal mostly migratory and have served as ‘pathfinders’ discovering and temporarily mining many rich deposits of spectacular gemstones.
The government as part of the mining reform established the department of Artisanal and Small scale Miners to organise support and promote ASM. The general economic reforms have created an enabling investment climate with relatively cheap labour.
There are numerous viable opportunities for mining the rich and extensive near surface deposits of sapphire, ruby, emerald, aquamarine, tourmaline, and the rest, which are found in Nigeria and presently under-exploited. Investment in this sector allows foreign ownership or in partnership with local miners.
Trading: The guidelines and conditions for the establishment of private mineral buying centres (MBC) have been developed. Government is embarking on a drive for the registration of MBC nationwide which will provide opportunity for trading companies to establish gem buying centres in any part of Nigeria.
Processing: Since Nigeria is not ‘a consuming nation of gemstones’ much of the gemstone production is being exported rough. Only an insignificant portion is processed locally hence there are great opportunities for tumbling, beading, faceting, carving, and jewellery making in the country.
Investment opportunities in the gemstones business in Nigeria
There are abundant and diverse Inv... more Investment opportunities in the gemstones business in Nigeria
There are abundant and diverse Investment opportunities in the nascent colored gemstones industry in Nigeria and these include: mining, trading, brokering deals, and processing.
Mining: Mining of coloured gemstones is widespread in the nation and is mainly carried out by Artisans and Small scale Miners (ASM). The artisanal miners are informal mostly migratory and have served as ‘pathfinders’ discovering and temporarily mining many rich deposits of spectacular gemstones.
The government as part of the mining reform established the department of Artisanal and Small scale Miners to organise support and promote ASM. The general economic reforms have created an enabling investment climate with relatively cheap labour.
There are numerous viable opportunities for mining the rich and extensive near surface deposits of sapphire, ruby, emerald, aquamarine, tourmaline, and the rest, which are found in Nigeria and presently under-exploited. Investment in this sector allows foreign ownership or in partnership with local miners.
Trading: The guidelines and conditions for the establishment of private mineral buying centres (MBC) have been developed. Government is embarking on a drive for the registration of MBC nationwide which will provide opportunity for trading companies to establish gem buying centres in any part of Nigeria.
Processing: Since Nigeria is not ‘a consuming nation of gemstones’ much of the gemstone production is being exported rough. Only an insignificant portion is processed locally hence there are great opportunities for tumbling, beading, faceting, carving, and jewellery making in the country.
ABSTRACT
Undeformed pegmatites occur in the study area, Igbofia-Akwa Ibami-Iwuru axis, SE Nigeria... more ABSTRACT
Undeformed pegmatites occur in the study area, Igbofia-Akwa Ibami-Iwuru axis, SE Nigeria with an estimated area of about 230km2. About 40 pegmatites exposures were investigated and representative samples were analyzed with the view of understanding their geochemical characterization and thus deduce their economic potentials. These pegmatites were intruding and hosted by the metamorphic (schists and gniesses) and igneous rock unit (porphyritic and non-porphyritic granodiorites), which characterize the area. Macroscopic study shows large crystals of schorls, albite, plagioclase and quartz. Petrographic studies reveal that microcline, muscovite, and graphic textures of quartz are the dominant minerals, while tourmaline, garnet, zircon and opaques occur as accessories. This is typical of granitic pegmatites. Geochemical analysis carried out at the Activation Laboratory – Canada, shows the pegmatites to be peraluminous from estimated Aluminium Saturation Index (ASI) which is greater than one (1). Variation plot of Na2O + K2O vs. SiO2 classifies the rocks as alkali to subalkalic types. Estimation of Fe-number shows reasonably high values ranging between 0.66 – 0.77. Calculated Modified-Alkali-Lime-Index shows the pegmatites ranging from positive to negative values. SiO2 and Al2O3 values which averages at 67.74% and 14.49% respectively are lower when compared to pegmatites from similar fields in other parts of the country. But they are richer in Fe2O3 with an average value of 4.16%. Trace elements such as Ba, Sr, Zr, Rb, Ta, and Nb have average concentrations of 71.15, 27.50, 16.61, 344.70(ppm), 18.14(ppm), and 71.70(ppm) respectively. While the ratios K/Ba, and K/Cs have very high average values of 430.43 and 1291.30 respectively. Low values are believed to be indicative of mineralized pegmatites. Thus these extremely high values suggest that these pegmatites are barren and unmineralised. Further discrimination using various standard ratios and variation plots for rare-metal mineralization indicates a poor level of mineralization for the Iwuru pegmatites, while those of Igbofia and Akwa-Ibami shows very low degree of mineralization especially with respect to Ta-Nb.
Abstract
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o... more Abstract
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist and granodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against associated pegmatite samples in this work, show that the pegmatites are not necessarily products of their host rocks.
Abstract
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o... more Abstract
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist and granodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against associated pegmatite samples in this work, show that the pegmatites are not necessarily products of their host rocks.
Uploads
Papers by Emmanuel Igonor
There are abundant and diverse Investment opportunities in the nascent colored gemstones industry in Nigeria and these include: mining, trading, brokering deals, and processing.
Mining: Mining of coloured gemstones is widespread in the nation and is mainly carried out by Artisans and Small scale Miners (ASM). The artisanal miners are informal mostly migratory and have served as ‘pathfinders’ discovering and temporarily mining many rich deposits of spectacular gemstones.
The government as part of the mining reform established the department of Artisanal and Small scale Miners to organise support and promote ASM. The general economic reforms have created an enabling investment climate with relatively cheap labour.
There are numerous viable opportunities for mining the rich and extensive near surface deposits of sapphire, ruby, emerald, aquamarine, tourmaline, and the rest, which are found in Nigeria and presently under-exploited. Investment in this sector allows foreign ownership or in partnership with local miners.
Trading: The guidelines and conditions for the establishment of private mineral buying centres (MBC) have been developed. Government is embarking on a drive for the registration of MBC nationwide which will provide opportunity for trading companies to establish gem buying centres in any part of Nigeria.
Processing: Since Nigeria is not ‘a consuming nation of gemstones’ much of the gemstone production is being exported rough. Only an insignificant portion is processed locally hence there are great opportunities for tumbling, beading, faceting, carving, and jewellery making in the country.
There are abundant and diverse Investment opportunities in the nascent colored gemstones industry in Nigeria and these include: mining, trading, brokering deals, and processing.
Mining: Mining of coloured gemstones is widespread in the nation and is mainly carried out by Artisans and Small scale Miners (ASM). The artisanal miners are informal mostly migratory and have served as ‘pathfinders’ discovering and temporarily mining many rich deposits of spectacular gemstones.
The government as part of the mining reform established the department of Artisanal and Small scale Miners to organise support and promote ASM. The general economic reforms have created an enabling investment climate with relatively cheap labour.
There are numerous viable opportunities for mining the rich and extensive near surface deposits of sapphire, ruby, emerald, aquamarine, tourmaline, and the rest, which are found in Nigeria and presently under-exploited. Investment in this sector allows foreign ownership or in partnership with local miners.
Trading: The guidelines and conditions for the establishment of private mineral buying centres (MBC) have been developed. Government is embarking on a drive for the registration of MBC nationwide which will provide opportunity for trading companies to establish gem buying centres in any part of Nigeria.
Processing: Since Nigeria is not ‘a consuming nation of gemstones’ much of the gemstone production is being exported rough. Only an insignificant portion is processed locally hence there are great opportunities for tumbling, beading, faceting, carving, and jewellery making in the country.
Undeformed pegmatites occur in the study area, Igbofia-Akwa Ibami-Iwuru axis, SE Nigeria with an estimated area of about 230km2. About 40 pegmatites exposures were investigated and representative samples were analyzed with the view of understanding their geochemical characterization and thus deduce their economic potentials. These pegmatites were intruding and hosted by the metamorphic (schists and gniesses) and igneous rock unit (porphyritic and non-porphyritic granodiorites), which characterize the area. Macroscopic study shows large crystals of schorls, albite, plagioclase and quartz. Petrographic studies reveal that microcline, muscovite, and graphic textures of quartz are the dominant minerals, while tourmaline, garnet, zircon and opaques occur as accessories. This is typical of granitic pegmatites. Geochemical analysis carried out at the Activation Laboratory – Canada, shows the pegmatites to be peraluminous from estimated Aluminium Saturation Index (ASI) which is greater than one (1). Variation plot of Na2O + K2O vs. SiO2 classifies the rocks as alkali to subalkalic types. Estimation of Fe-number shows reasonably high values ranging between 0.66 – 0.77. Calculated Modified-Alkali-Lime-Index shows the pegmatites ranging from positive to negative values. SiO2 and Al2O3 values which averages at 67.74% and 14.49% respectively are lower when compared to pegmatites from similar fields in other parts of the country. But they are richer in Fe2O3 with an average value of 4.16%. Trace elements such as Ba, Sr, Zr, Rb, Ta, and Nb have average concentrations of 71.15, 27.50, 16.61, 344.70(ppm), 18.14(ppm), and 71.70(ppm) respectively. While the ratios K/Ba, and K/Cs have very high average values of 430.43 and 1291.30 respectively. Low values are believed to be indicative of mineralized pegmatites. Thus these extremely high values suggest that these pegmatites are barren and unmineralised. Further discrimination using various standard ratios and variation plots for rare-metal mineralization indicates a poor level of mineralization for the Iwuru pegmatites, while those of Igbofia and Akwa-Ibami shows very low degree of mineralization especially with respect to Ta-Nb.
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist and granodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against associated pegmatite samples in this work, show that the pegmatites are not necessarily products of their host rocks.
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist and granodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against associated pegmatite samples in this work, show that the pegmatites are not necessarily products of their host rocks.
There are abundant and diverse Investment opportunities in the nascent colored gemstones industry in Nigeria and these include: mining, trading, brokering deals, and processing.
Mining: Mining of coloured gemstones is widespread in the nation and is mainly carried out by Artisans and Small scale Miners (ASM). The artisanal miners are informal mostly migratory and have served as ‘pathfinders’ discovering and temporarily mining many rich deposits of spectacular gemstones.
The government as part of the mining reform established the department of Artisanal and Small scale Miners to organise support and promote ASM. The general economic reforms have created an enabling investment climate with relatively cheap labour.
There are numerous viable opportunities for mining the rich and extensive near surface deposits of sapphire, ruby, emerald, aquamarine, tourmaline, and the rest, which are found in Nigeria and presently under-exploited. Investment in this sector allows foreign ownership or in partnership with local miners.
Trading: The guidelines and conditions for the establishment of private mineral buying centres (MBC) have been developed. Government is embarking on a drive for the registration of MBC nationwide which will provide opportunity for trading companies to establish gem buying centres in any part of Nigeria.
Processing: Since Nigeria is not ‘a consuming nation of gemstones’ much of the gemstone production is being exported rough. Only an insignificant portion is processed locally hence there are great opportunities for tumbling, beading, faceting, carving, and jewellery making in the country.
There are abundant and diverse Investment opportunities in the nascent colored gemstones industry in Nigeria and these include: mining, trading, brokering deals, and processing.
Mining: Mining of coloured gemstones is widespread in the nation and is mainly carried out by Artisans and Small scale Miners (ASM). The artisanal miners are informal mostly migratory and have served as ‘pathfinders’ discovering and temporarily mining many rich deposits of spectacular gemstones.
The government as part of the mining reform established the department of Artisanal and Small scale Miners to organise support and promote ASM. The general economic reforms have created an enabling investment climate with relatively cheap labour.
There are numerous viable opportunities for mining the rich and extensive near surface deposits of sapphire, ruby, emerald, aquamarine, tourmaline, and the rest, which are found in Nigeria and presently under-exploited. Investment in this sector allows foreign ownership or in partnership with local miners.
Trading: The guidelines and conditions for the establishment of private mineral buying centres (MBC) have been developed. Government is embarking on a drive for the registration of MBC nationwide which will provide opportunity for trading companies to establish gem buying centres in any part of Nigeria.
Processing: Since Nigeria is not ‘a consuming nation of gemstones’ much of the gemstone production is being exported rough. Only an insignificant portion is processed locally hence there are great opportunities for tumbling, beading, faceting, carving, and jewellery making in the country.
Undeformed pegmatites occur in the study area, Igbofia-Akwa Ibami-Iwuru axis, SE Nigeria with an estimated area of about 230km2. About 40 pegmatites exposures were investigated and representative samples were analyzed with the view of understanding their geochemical characterization and thus deduce their economic potentials. These pegmatites were intruding and hosted by the metamorphic (schists and gniesses) and igneous rock unit (porphyritic and non-porphyritic granodiorites), which characterize the area. Macroscopic study shows large crystals of schorls, albite, plagioclase and quartz. Petrographic studies reveal that microcline, muscovite, and graphic textures of quartz are the dominant minerals, while tourmaline, garnet, zircon and opaques occur as accessories. This is typical of granitic pegmatites. Geochemical analysis carried out at the Activation Laboratory – Canada, shows the pegmatites to be peraluminous from estimated Aluminium Saturation Index (ASI) which is greater than one (1). Variation plot of Na2O + K2O vs. SiO2 classifies the rocks as alkali to subalkalic types. Estimation of Fe-number shows reasonably high values ranging between 0.66 – 0.77. Calculated Modified-Alkali-Lime-Index shows the pegmatites ranging from positive to negative values. SiO2 and Al2O3 values which averages at 67.74% and 14.49% respectively are lower when compared to pegmatites from similar fields in other parts of the country. But they are richer in Fe2O3 with an average value of 4.16%. Trace elements such as Ba, Sr, Zr, Rb, Ta, and Nb have average concentrations of 71.15, 27.50, 16.61, 344.70(ppm), 18.14(ppm), and 71.70(ppm) respectively. While the ratios K/Ba, and K/Cs have very high average values of 430.43 and 1291.30 respectively. Low values are believed to be indicative of mineralized pegmatites. Thus these extremely high values suggest that these pegmatites are barren and unmineralised. Further discrimination using various standard ratios and variation plots for rare-metal mineralization indicates a poor level of mineralization for the Iwuru pegmatites, while those of Igbofia and Akwa-Ibami shows very low degree of mineralization especially with respect to Ta-Nb.
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist and granodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against associated pegmatite samples in this work, show that the pegmatites are not necessarily products of their host rocks.
The area of study (Igbofia-Akwa Ibami-Iwuru) is located between Latitudes 5o20'N and 5o27'N, and Longitudes 8o09'E and 8o18'E, south-eastern Nigeria. The pegmatites of this area have been studied by several authors for several decades till now. The present study evaluates the use of trace and rare-earth elements (REE) as finger prints in comparing the geochemistry of pegmatites and their associated host rocks, and to deduce if there is any co-genetic relationship between them. Sixteen representative samples of pegmatites and their host rocks (schist and granodiorites) were collected and analysed using the ICP-MS analytical method. The pegmatites were found to be richer than their host rocks in SiO2, Al2O3 Na2O+K2O (alkali), Rb, Li, Cs, Be, Na, Zn, Nb, and Ga while they are poorer in Fe2O3, CaO, Sr, Ba, Zr, U, Cr, Th, and all the REEs. Only in the MgO contents are the rocks similar. Compared trace elements and REE data of schist and granodiorite (host rocks) against associated pegmatite samples in this work, show that the pegmatites are not necessarily products of their host rocks.