Rare Earth Elements Assessment in the Granitoids of Part of Southwestern Nigeria

The Rare Earth Elements (REE) composition of granitoids in and around Ila-Orangun area Southwestern Nigeria was assessed in order to ascertain their potential for possible exploitation. Detailed lithological mapping of the area was undertaken followed by whole rock geochemical analysis of representative samples of the granitoids using Inductively Coupled Plasma Mass Spectrometry (ICP-MS) technique. Petrographic study of the samples was carried out as well as the interpretation of the geochemical data using diverse geochemical discrimination plots. The rock units mapped were biotite granite gneiss, granite gneiss and hornblende biotite granite. Biotite hornblende gneiss, quartzite, talc-chlorite-tremolite-schist, mica schist and pegmatites were the surrounding country rocks. The REE concentrations (in ppm) revealed higher concentrations of the light REEs compared to the heavy REEs. The fractionation ratio, (La/Yb)N ranged from 4.35-15.04 (granite gneiss) and 13.78-18.48 (hornblende biotite granite) indicating enrichment in LREEs over the HREEs. The spider plot for the REEs also showed that the granitoids are LREE-enriched and HREE-depleted suggesting fractional crystallisation and a distinct negative Eu anomaly indicating plagioclase fractionation. Enrichment plot also revealed that the REEs in the granitoids are significantly enriched. Comparison with other areas showed that the granitoids of the study area especially the hornblende biotite granite has higher concentrations of REEs and may be a possible pointer of REE mineralisation.

Investigations on radioelements occurrences in rocks in Kakuri Area of Kaduna North West, Nigeria

Detailed investigations on Radioelements occurrences in rocks in Kakuri Area Kaduna North West Nigeria were carried out in this work using Geochemical ground follow-up methods. The methods employed include Atomic Absorption Spectrometric (AAS) and Assay of rock samples from the area. Fresh rock samples were collected with hammer and identified as follows: Granite gneiss, Granite, Migmatites and Gneiss. Analysis was made on the powdered rock samples and histograms were plotted to determine the activity of Radioelement concentrations: Potassium, Thorium and Uranium in each of the samples analyzed. Results of the investigations showed high concentration of potassium (40K) and other Radioelements, thorium and uranium in the area. Generally, the results delineate the three Radioelements in terms of their anomaly pattern within the study area.Keywords: Geochemical Survey; Aeroradiometric Anomaly; Fresh Rocks; Radioelements and Kakuri Area

THERMOCHRONOLOGY OF GRANITOID BATHOLITHS AND THEIR TRANSFORMATION INTO METAMORPHIC CORE COMPLEXES (EXAMPLE OF SONG‐CHAI MASSIF, NORTHERN VIETNAM)

Based on the reconstruction of the thermal evolution of granitoid batholith, represented by the Song‐Chai gneiss‐granite massif (Northern Vietnam), the long‐term existence of granitoid magma at deep levels of the Earth's crust (H≥25 km, Δt~20–50 Ma) is established. The geodynamic analysis of the granitoid batholith and mathematical modeling of its thermal history shows that the magmatic chamber should be considered as a thermal trap at the lower level of the crust, which preserved residual granite melts for a long time. Activation of the magmatic chamber occurs in post‐collisional strike‐slip fault zones and is accompanied by tectonic exhumation of large crustal segments. As a result, the batholith is transformed into a Cordilleran‐type metamorphic core complex, residual rare‐metal melts are emplaced, and, commercial deposits are thus formed.

Assessment of Magnetic Susceptibility of Some Selected Rock Samples from Karu Area, Northcentral Nigeria

Magnetic susceptibility is a very sensitive indicator of magnetic minerals present in rock because any slight variation in magnetic mineralogy is usually reflected by a profound change of susceptibility. However, the knowledge of its mineral composition does not provide adequate information about the rock and mineral composition of rock and properties such as magnetic susceptibility determines the property of rock. Six samples of the rocks were obtained at different two quarries site each located at Nyanya and Karu for the assessment of magnetic susceptibility which were measured with an instrument called magnetic susceptibility meter EM2S+. The results obtained shows that limestone has low magnetic susceptibility compared to other rock samples such as pegmatite, quartzite, gneiss, granite, granite gneiss, sand stone in both site and pegmatite has the low magnetic susceptibility compared to other rock samples in Karu. The average magnetic susceptibility of the rock samples from Nyanya and Karu are 4.11 x 10-4 (SI) and 4.99 x 10-4(SI) respectively. In conclusion, the selected rock samples show that granite gneiss > laterite > sand stone > granite > gneiss > quartzite > pegmatite > limestone. Which indicate that limestone has the low magnetic susceptibility than other rock samples, show the present of Felsic materials while granite gneiss has a very high magnetic susceptibility, as a result of the present of large amount of iron and magnesium in it.

Research on forest terrain roughness as a source of dynamic action on the vehicle

The issue of terrain conditions is very complex and its description is approached from different perspectives and with different objectives. Because it consists of the gathering of basic information for a mobile object, a wheeled forestry tractor, the terrain-vehicle approach was taken as the basis. Ground conditions are part of the operating conditions of wheeled forestry tractors. Uneven ground can be regarded as a source of vibration in the vehicle – towing truck. In this respect, given the random shape of the surface roughness, the solution to vibrations leads to a terrain correlation analysis in order to obtain a correlation function and power spectral density of the ground surface. Scanning of the ground micro-profile was performed using a device for quick terrain scanning, which from the mechanical aspect consists of a towing vehicle and a measuring carriage. Correlation function and power spectral density are the evaluation based on ground micro-profile measurements and the results of calculations. Measurements of forest terrain (road) micro-profile were done in the area of Little Fatra and Little Carpathians in Slovakia. In geological terms, the measurements were done in an area with the occurrence of gneiss, granite, limestone and flysch. No measurements were performed in a sandy area.

Mineralogy and Geochemistry of the Weathering Profiles above the Basement Rocks in Idi- Ayunre and Akure Districts, Southwestern Nigeria

Idi-ayunre and Akure areas are part of the basement complex of southwestern Nigeria and are predominantly consisted of gneisses, granite and migmatite with some minor quartz veins and pegmatite. These rocks have been greatly weathered to form clay, laterite and soils.Chemical analysis were carried out on basement rocks and exposed profiles. The weathering profile was subjected to X ray diffraction (XRD) analysis to determine mineralogical compositions whereas Chemical Index of Alteration (CIA) was calculated from the elemental concentrated data.Weathering of basement rocks in Idi-Ayunre and Akure districts resulted in the formation of soil layer which ranged 0-0.4m, laterite layer 1.2-2.2m, and clayey zone 3.8-6.6m. Quartz, plagioclase, microcline, and biotite were the main minerals in parent rocks. Some of the primary minerals such as biotite and K-feldspar have been weathered to form kaolinite. Quartz, kaolinite and goethite formed the dominant minerals revealed by X-ray diffraction on decomposed granite sequences. The results from chemical analysis showed that Al and Fe have been enriched in weathering profiles of banded gneiss, migmatite gneiss and porphyritic granite whilst on the other hand Ca, Mg, Mn, Na, K, Ti were reported to be depleted.. Silica was relatively stable from basement to the topsoil in the profile. The CIA generally ranged between 80 - 99The lateritic profiles over banded gneiss, granite and porphyritic granite of Idi-Ayunre and Akure areas varied with the composition of the parent rocks. The thick clayey layers could be of great economic importance for the production of ceramics wares and for constructional purposes.

Analysis of Features and Causation of Rock Burst of Qirehataer Diversion Tunnel

Rock burst will happened when the underground engineering is excavated in the hard and brittle rock mass because of high in situ stress or concentrated stress. The length of Qirehataer diversion tunnel is 15.639km,and the maximum over-depth is 1720m. With excavation of tunnel, lightly to moderate rock burst had taken place in 600m length about of tunnel, and moderate rock burst locally. The mainly lithology of tunnel is gneiss granite and the percent is 64.5%, uniaxial compressive strength of which is 63.5MPa so it should be classified hard rock. The maximum principle stress is 30MPa in the place of rock bust. This paper analysis engineering geology conditions of this area and the characters of rock burst, author concludes that posteriority and continuity for time and Traceability and continuity for place are different from others rock burst examples. The reason is that course of stress adjustment is continually and repetitive.

Lithologie des cailloux de la baie de Montmagny, côte sud du Saint-Laurent, Québec

RÉSUMÉ À Montmagny, sur la rive sud de l'estuaire du Saint-Laurent, à environ 75 km en aval de Québec, d'abondants cailloux de lithologies variées parsèment la zone intertidale, malgré l'absence de dépôts grossiers en bordure du rivage actuel. Les cailloux reposent directement sur un substrat composé de sable fin, limon, vase et argile marine. Ce milieu, dominé par la sédimentation fine, se révèle donc assez original puisqu'il implique des agents de transport et de mise en place fort différents: d'un côté, vagues, courants et marées, de l'autre, les glaces flottantes. L'abondance des cailloux a permis de faire de nombreux comptages et de calculer les pourcentages de chacune des lithologies représentées. Les 42 105 cailloux comptés comprennent 19,9% d'éléments précambriens (gneiss, granite, anorthosite, etc.), 59,5 % de grès, 13,6 % des schistes. 6 % de calcaires et 1 % de conglomérats. Les cailloux proviennent de trois grandes unités géologiques: le Bouclier laurentidien (Précambrien) au nord, les formations côtières appalachiennes (Cambro-Ordovicien) au sud et les formations sédimentaires des basses terres du Saint-Laurent (Ordovicien) au sud-ouest. Bien qu'une forte proportion des cailloux soit d'origine locale, une partie a subi des déplacements de l'ordre de 100 à 200 km. Les glaces flottantes constituent le principal agent de transport et de mise en place.

The vegetation of granite rock outcrops in Rio de Janeiro, Brazil, and the need for its protection

Rock outcrop communities usually receive very little attention from scientists and environmentalists. We examined the vegetation occurring in eight gneiss-granite rock outcrops at Rio de Janeiro State (Brazilian Atlantic coast) which exists in natural associations on soil islands. A total of 86 vascular plant species, belonging to 30 families, was found on 347 soil islands. Bromeliaceae, Asteraceae and Velloziaceae species were the most frequent plants, many of them endemic to these habitats. Ordination and cluster analyses using species frequency on each site made evident some major distinctions related to local influences, most probably the proximity to the sea. Each outcrop presented high values of the Shannon-Wiener index of species diversity. Species richness was very dependent on the total area, and high beta diversity was observed amongst sites. Similarities with the South American and African rock-outcrop communities were found. Despite their uniqueness as habitats, their possession of several endemic species and the fragility of the ecosystem involved, Brazilian rock outcrops are not protected by specific environmental legislation and we propose urgent actions for their protection.