scholarly journals Petrography of Allanite-bearing Tonalite from Iwo Region, Osun State, Nigeria

2020 ◽  
Vol 67 (2) ◽  
pp. 79-89
Author(s):  
E.J. Oziegbe ◽  
O.O. Ocan ◽  
A.O. Buraimoh
Keyword(s):  
Alkali Feldspar ◽  
Precambrian Basement ◽  
Basement Complex ◽  
Southwestern Nigeria ◽  
Compositional Zoning ◽  
Thin Sections ◽  
Accessory Minerals ◽  
Secondary Minerals ◽  
Mineral Assemblages ◽  
Opaque Minerals

AbstractPrimary, secondary and accessory minerals in tonalitic rocks from Iwo region of the Precambrian Basement Complex of Southwestern Nigeria were identified and analysed with the aim of determining the various processes involved during the crystallisation of magma. Thin sections of tonalite were prepared and studied with the aid of a petrographic microscope. The mineral assemblages observed are biotite, plagioclase, alkali-feldspar, amphiboles, pyroxene, quartz, muscovite and chlorite. Allanite, titanite, apatite and zircon occur as accessory minerals. Muscovite and chlorite are found to be secondary minerals. The mineral allanite has a characteristic form of zoning and shows evidence of metamictisation, and is surrounded by dark-coloured biotite having radioactive haloes. Titanite is anhedral to subhedral crystals and forms reaction rim round opaque minerals. Plagioclase shows evidence of compositional zoning as well as plastic deformation of the twin lamellae. The allanite observed is primary in nature and has undergone radioactive disintegration; chlorite and muscovite are formed by secondary processes of chloritization and sericitisation, respectively. The tonalite is formed as a result of rapid cooling of magma close to the Earth's surface.

Leka Ophiolite Complex as analogy to the serpentinization-carbonation system on Mars.

2021 ◽  
Author(s):  
benjamin bultel ◽  
Agata M. Krzesinska ◽  
Damien Loizeau ◽  
François Poulet ◽  
Håkon O. Astrheim ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Ground Truth ◽  
Ultramafic Rocks ◽  
Ophiolite Complex ◽  
Spectral Parameters ◽  
Thin Sections ◽  
Accessory Minerals ◽  
Mineral Assemblages ◽  
Alteration Minerals

<p>Serpentinization and carbonation have affected ultramafic rocks on Noachian Mars in several places called here serpentinization-carbonation systems (SCS). Among the most prominent SCS revealing mineral assemblages characteristic of serpentinization/carbonation is the Nili Fossae region [1]. Jezero crater – the target of the Mars 2020 rover –hosted a paleolake which constitutes a sink for sediments from Nili Fossae [1]. Thanks to the near infrared spectrometer onboard Mars2020 [2], the mission has the potential to offer ground truth measurement for other putative serpentinization/carbonation system documented on Mars. Several important aspects that may be addressed are: Do carbonates result from primary alteration of olivine-rich lithologies or are they derived by reprocessing of previous alteration minerals [3]? What is the composition? and nature of the protolith, which appear to be constituted of considerable amounts of olivine [4]? To reveal critical information regarding the conditions of serpentinization/carbonation, accessory minerals need detailed studies [1; 5]. In case of Jezero Crater, and serpentinization on Mars in general, the main alteration minerals are identified, but little is known about the accessory minerals.</p> <p>The Nili Fossae-Jezero system has potential analogues in terrestrial serpentinized and carbonated rocks, such as the Leka Ophiolite Complex, Norway (PTAL collection, https://www.ptal.eu). Here, distinct mineral assemblages record different stages of hydration and carbonation of ultramafic rocks [6].</p> <p>We perform petrological and mineralogical analyses on thin sections to characterize the major and trace minerals and combine with Near Infrared (NIR) spectroscopy measurements. A set of spectral parameters are defined and compare to spectral parameters previously used on CRISM and OMEGA data [1, 4, 7, 8]. We study the significance of the mineralogical assemblages including nature of accessory minerals. Effect of the presence of accessory minerals on the NIR signal is investigated and their potential incidence on the amount of H<sub>2</sub>/CH<sub>4</sub> production in mafic or ultramafic system is discussed [5].</p> <p>We started to apply the newly defined spectral parameters on several SCS on Mars. Results confirm local carbonation of earlier serpentinized rocks and suggest that different protoliths could have led to diversity of mineralogical associations in SCS on Mars. Multiple detection of brucite are also suggested for the first time on Mars. Altogether our results help to better describe key geochemical conditions of the SCS on Mars for habitability potential of the martian crust and Mars’s evolution.</p> <p><strong> </strong></p> <p>References:</p> <ul> <li>Brown, A. J., et al. <em>EPSL</em>1-2 (2010): 174-182.</li> <li>Wiens, R.C., et al.  <em>Space Sci Rev</em><strong>217, </strong>4 (2021).</li> <li>Horgan, B., et al. <em>Second International Mars Sample Return</em>. Vol. 2071. 2018.</li> <li>Ody, A., et al. <em>JGR: Planets</em>2 (2013): 234-262.</li> <li>Klein, F., et al. <em>Lithos</em>178 (2013): 55-69.</li> <li>Bjerga, A., et al. <em>Lithos</em>227 (2015): 21-36.</li> <li>Viviano-Beck et al, <em>JGR: Planets 11</em>8.9 (2013)</li> <li>Viviano-Beck et al, <em>JGR: Planets 119.6</em> (2014)</li> </ul>

scholarly journals Mineralogy and Geochemistry of Residual Clay Occurrences in Idi-Ayunre and Akure Areas, Southwestern Nigeria

2015 ◽  
Vol 7 (4) ◽  
pp. 23 ◽  
Author(s):  
Adewole J. Adeola
Keyword(s):  
Raw Materials ◽  
Thermal Characteristic ◽  
Granite Gneiss ◽  
Industrial Applications ◽  
Precambrian Basement ◽  
X Ray Diffraction ◽  
Basement Complex ◽  
Southwestern Nigeria ◽  
X Ray ◽  
Porphyritic Granite

<p class="zhengwen">Three residual clay occurrences in Idi-Ayunre, and Akure areas which belong to the Precambrian basement complex of southwestern Nigeria were investigated for their mineralogical, chemical and industrial properties. The investigation was to evaluate their industrial applications and economic importance. The clay within the weathered profiles above banded gneiss at Idi-Ayunre is whitish with red spots, whereas the clays derived from profiles above porphyritic granite and granite gneiss in Akure are grayish and brown in color respectively.</p><p class="zhengwen">The X-ray diffraction studies show that kaolinite is the dominant clay mineral, goethite, microcline, quartz, albite are the major non clay minerals in the samples. Chemical data showed that the average values of SiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, and Fe<sub>2</sub>O<sub>3</sub> were 52.3. 30.29 and 3.54 wt% respectively constituting 86.13% of the bulk compositions.</p>Evaluation of the clay thermal characteristic, firing colour, water absorption capacities and shrinkage values show that the brownish Idi-Ayunre clay, gray and brown Akure kaolinitic clays could serve as raw materials for ceramics, building bricks, and other structural wares

scholarly journals EDX-SEM-XRF data from selected Precambrian Basement Complex rock samples in part of Southwestern Nigeria

Data in Brief ◽  
2018 ◽  
Vol 20 ◽  
pp. 1525-1531 ◽  
Author(s):  
J.S. Kayode ◽  
Y. Yusup ◽  
M.N.M. Nawawi ◽  
K.S. Ariffin ◽  
A.E. Kalil ◽  
...  
Keyword(s):  
Precambrian Basement ◽  
Basement Complex ◽  
Southwestern Nigeria ◽  
Rock Samples

Leka Ophiolite Complex as analogy to the serpentinization-carbonation system on Mars.

2021 ◽  
Author(s):  
Benjamin Bultel ◽  
Agata Krzesinska ◽  
Damien Loizeau ◽  
François Poulet ◽  
Håkon O. Astrheim ◽  
...  
Keyword(s):  
Near Infrared ◽  
Nir Spectroscopy ◽  
Remote Sensing Data ◽  
Ground Truth ◽  
Ultramafic Rocks ◽  
Ophiolite Complex ◽  
Thin Sections ◽  
Accessory Minerals ◽  
Mineral Assemblages ◽  
Alteration Minerals

&lt;p&gt;Serpentinization and carbonation have affected ultramafic rocks on Noachian Mars in several places. Among the most prominent systems revealing mineral assemblages characteristic of serpentinization/carbonation is the Nili Fossae region [1]. Jezero crater &amp;#8211; the target of the Mars 2020 rover &amp;#8211;hosted a paleolake which constitutes a sink for sediments from Nili Fossae [1]. Thanks to the near infrared spectrometer onboard Mars2020 [2], the mission has the potential to offer ground truth measurement for other putative serpentinization/carbonation system documented on Mars. Several important aspects that may be addressed are: Do carbonates result from primary alteration of olivine-rich lithologies or are they derived by reprocessing of previous alteration minerals [3]? What is the composition? and nature of the protolith, which appear to be constituted of considerable amounts of olivine [4]? To reveal critical information regarding the conditions of serpentinization/carbonation, accessory minerals need detailed studies [1; 5]. In case of Jezero Crater, and serpentinization on Mars in general, the main alteration minerals are identified, but little is known about the accessory minerals.&lt;/p&gt;&lt;p&gt;The Nili Fossae-Jezero system has potential analogues in terrestrial serpentinized and carbonated rocks, such as the Leka Ophiolite Complex, Norway (PTAL collection, https://www.ptal.eu). Here, distinct mineral assemblages record different stages of hydration and carbonation of ultramafic rocks [6].&lt;/p&gt;&lt;p&gt;We perform petrological and mineralogical analyses on thin sections to characterize the major and trace minerals and combine with Near Infrared (NIR) spectroscopy measurements. We study the significance of the mineralogical assemblages including solid solution composition and nature of accessory minerals. Effect of the presence of accessory minerals on the NIR signal is investigated and their potential incidence on the amount of H&lt;sub&gt;2&lt;/sub&gt;/CH&lt;sub&gt;4&lt;/sub&gt; production in mafic or ultramafic system is discussed [5; 8]. This could improve our understanding of serpentinization and carbonation processes on Mars, which can guide future in-situ operations and also help for a better interpretation of the remote sensing data acquired on other possible serpentinization/carbonation systems.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;&amp;#160;&lt;/strong&gt;References:&lt;/p&gt;&lt;p&gt;1. Brown, A. J., et al. EPSL297.1-2 (2010): 174-182.&lt;/p&gt;&lt;p&gt;&lt;span&gt;2. Wiens, R.C., et al.&amp;#160;&amp;#160;Space Sci Rev217&lt;/span&gt;&lt;strong&gt;,&amp;#160;&lt;/strong&gt;&lt;span&gt;4 (2021).&lt;/span&gt;&lt;/p&gt;&lt;p&gt;3. Horgan, B., et al. Second International Mars Sample Return. Vol. 2071. 2018.&lt;/p&gt;&lt;p&gt;4. Ody, A., et al. JGR: Planets118.2 (2013): 234-262.&lt;/p&gt;&lt;p&gt;5. Klein, F., et al. Lithos178 (2013): 55-69.&lt;/p&gt;&lt;p&gt;6. Bjerga, A., et al. Lithos227 (2015): 21-36.&lt;/p&gt;&lt;p&gt;7. Bultel, B. (Doctoral dissertation, Lyon). (2016).&lt;/p&gt;

scholarly journals Petrochemistry and petrogenesis of the Precambrian Basement Complex rocks around Akungba-Akoko, southwestern Nigeria

2020 ◽  
Vol 66 (3) ◽  
pp. 173-183 ◽  
Author(s):  
Abimbola Chris Ogunyele ◽  
Oladotun Afolabi Oluwajana ◽  
Iyanuoluwa Queen Ehinola ◽  
Blessing Ene Ameh ◽  
Toheeb Akande Salaudeen
Keyword(s):  
Granite Gneiss ◽  
Biotite Granite ◽  
Geological Mapping ◽  
Precambrian Basement ◽  
Biotite Gneiss ◽  
Basement Complex ◽  
Southwestern Nigeria ◽  
Anhydrous Mineral ◽  
Geochemical Analyses ◽  
Igneous Protoliths

AbstractField, mineralogical and petrochemical studies of the Precambrian Basement Complex rocks around Akungba-Akoko were carried out with the aim of determining their petrology, petrochemical characteristics and petrogenesis. The petrology of Akungba-Akoko area comprises migmatite, granite gneiss and biotite gneiss intruded by biotite granite, charnockite and minor felsic and basic rocks. Seventeen representative samples of the granite gneiss, biotite gneiss, biotite granite and charnockite were collected during field geological mapping of the area for petrographic and geochemical analyses. Modal mineralogy revealed that the granite gneiss, biotite gneiss and granite have assemblages of quartz + feldspar + mica + hornblende + opaques and are granitic in composition. The charnockite is characterized by anhydrous mineral assemblage of quartz + feldspar + biotite + hornblende + pyroxene + opaques. Petrochemical data of the rocks revealed that they are moderately to highly enrich in SiO2, sub-alkaline, peraluminous, magnesian to ferroan and calcic and have K/Rb < 283. The geochemical characteristics and discrimination of the rocks indicated that the granite gneiss and biotite gneiss are orthogneisses formed by metamorphism of igneous protoliths of granitic composition and the biotite granite and charnockite are of igneous/magmatic origin. The biotite granite, charnockite and the igneous protoliths of the biotite gneiss are I-type granitoids formed from crustal igneous-sourced melt(s), while the igneous protoliths of the granite gneiss is a S-type granitoid probably derived from shallow crustal or sedimentary-sourced melt(s). Tectonic discrimination of the rocks indicated that they were formed during a phase of magmatic activity related to collision and subduction.

Electromagnetic Profiling for Groundwater in Precambrian Basement Complex Areas of Nigeria

1990 ◽  
Vol 21 (3) ◽  
pp. 205-216 ◽  
Author(s):  
A. Idowu Olayinka
Keyword(s):  
Water Supply ◽  
Complex Terrain ◽  
High Conductivity ◽  
The Other ◽  
Precambrian Basement ◽  
Basement Complex ◽  
Rural Water Supply ◽  
Well Yield ◽  
Rural Water ◽  
Borehole Drilling

Ground electromagnetic profiling, using a Geonics EM34-3 instrument, has been employed to identify areas of high conductivity in a Precambrian basement complex terrain of Nigeria. Field examples, conducted as part of a rural water supply programme, are presented. They indicate that the apparent conductivities are generally lower than about 60 mmho m−1. Subsequent borehole drilling suggests a good correlation between high EM34 anomalies, deep weathering and high well yield (&gt; 1 1 s−1). On the other hand, boreholes sited on conductivity lows penetrated a thinner regolith with relatively lower yields.

Laboratory-Based Bacterial Weathering of the Merensky Reef and Its Impact on Platinum Group Mineral Migration

2021 ◽  
Author(s):  
Ling Tan ◽  
Thomas Jones ◽  
Jianping Xie ◽  
Xinxing Liu ◽  
Gordon Southam
Keyword(s):  
Base Metal ◽  
Mineral Dissolution ◽  
Metal Sulfides ◽  
Acidithiobacillus Thiooxidans ◽  
Thin Sections ◽  
Secondary Minerals ◽  
Merensky Reef ◽  
Fe Oxides ◽  
Base Metal Sulfides ◽  
Platinum Group

Abstract Weathering of the Merensky reef was enhanced under laboratory conditions by Fe- and S-oxidizing bacteria: Acidithiobacillus ferrooxidans, Acidithiobacillus thiooxidans, and Leptospirillum ferrooxidans. These bacteria preferentially colonized pyrrhotite and pyrite, versus pentlandite and chalcopyrite (all of which were common within the rock substrate), promoting weathering. Weathering of base metal sulfides resulted in the precipitation of Fe oxides, Fe phosphate, and elemental sulfur as secondary minerals. Fe pyroxene weathered readily under acidic conditions and resulted in mineral dissolution, while other silicates (orthopyroxene and plagio-clase) precipitated Fe phosphate spherules or coatings on their surface. The deterioration of the platinum group metal (PGM) matrix (base metal sulfides and silicates) and the occurrence of a platinum grain associated with platinum nanoparticles observed in the biotic thin sections demonstrate that biogeochemical acid weathering is an important step in the active release of intact PGM grains. A platinum grain embedded in secondary Fe oxides/phosphate that had settled by gravity within the weathering solution demonstrates that secondary minerals that formed during weathering of PGM-hosting minerals also represent targets in PGM exploration by trapping and potentially slowing PGM migration. Dispersion halos surrounding or occurring downstream from PGM occurrences will likely produce two physical target classes—i.e., grains and colloids—under surficial weathering conditions.

Sign in / Sign up

Export Citation Format

Share Document