The petrographical and physical properties of major Precambrian basement rocks in Ado-Ekiti, Nigeria, were evaluated with a view to determine their suitability as road construction aggregates. Fifty rock samples were collected and subjected to petrographic evaluation and laboratory tests (water absorption capacity, specific gravity, Los Angeles abrasion value, aggregate crushing value, aggregate impact value and ten percent fines, flakiness index and unconfined compressive strength). Petrographical analysis revealed that the rocks (migmatite gneiss, quartzite, granite and charnockite) were predominantly acidic, rich in quartzo-feldspathic minerals. Opaque minerals in the rock units ranged between 0.6 and 2.3 % with maximum value in fine-grained charnockite. The specific gravity of the rock aggregates ranged between 2.65 and 2.74. All water absorption capacity values conform to recommended standard value of water absorption capacity \2 %. The aggregate crushing value of the rocks ranged between 17.6 and 28.4 % with minimum from quartzite (17.60-18.40 %) and highest in migmatite gneiss (27.70-28.40 %). The aggregate impact value ranged between 11.0 and 19.0 %, with the lowest value (11.0-11.6 %) from quartzite and highest in charnockite (18.4-19.0 %). Other properties including Los Angeles abrasion, ten percent fines, flakiness index and unconfined compressive strength ranged 17. 4-29.8 %, 96.96-131.63 kN, 13 and 24.9 and 138.98-167.52 MPa, respectively. Based on physical and mechanical properties of the rock aggregates in this study, quartzite, and fine-medium grained granites were considered most suitable for road aggregates production as the tests were within the acceptable limits for general road aggregates purposes. Porphyritic granite, the migmatite gneiss and charnockites showed results for which most values were outside, at the margin or slightly within the acceptable limits for general road stone purpose. The geotechnical assessment provided by this study revealed that not all the Precambrian basement rocks would yield aggregates that are satisfactory for use as road aggregates.

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The volcanic rocks in Semporna Peninsula, Sabah, Malaysia forms parts of the Miocene subjected slab during the Miocene-Pliocene orogeny. This study presents new petrographic and geochemical data of volcanic rocks in Semporna area. The volcanic rocks range in composition from basaltic andesite, andesite, dacite to rhyolite, with most of the volcanic shows calc-alkaline affinity with a minor tholeiitic feature. The trace elements shows enrichment in large-ion lithophile elements (LILE) and light rare earth elements (LREE) suggesting that the volcanic rocks have similar geochemical patterns and might come from similar magma source. The petrochemical data suggests that volcanic rocks of Semporna shows characteristic of subduction zone (negative Nb, Ta, and Ti). Decreasing magnitude of Europium anomalies from intermediate to acid lavas suggests an important role of plagioclase in the fractional crystallization. Negative Ce anomaly in part of Semporna volcanic rocks suggest that those volcanic rocks may related with emergence of oxygenated deep-sea environment. Tectonic diagrams showed that the Semporna volcanic rocks were formed in an island arc setting.