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.
Idanre granite batholith in southwestern Nigeria contain three rock types, namely, Older granite undifferentiated (OGu), Older granite porphyritic (OGp) and Older granite fine-grained (OGf). The granitoids intruded into a basement rock of primarily migmatite gneiss. Petrography indicates that quartz, orthoclase, hornblende, and biotite are common to all members while microcline is more prominent in OGp and plagioclase is poorly represented in OGf. Despite minor differences in petrographic features, the granite units generally have similar geochemical relationships. The average SiO2 contents in OGp (70.49%), OGu (68.7%) and OGf (65.8%) are comparable to similar Pan-African suites located in eastern and northern Nigeria. Na2O+K2O-CaO versus SiO2 diagram shows all the granite members are calcic, K2O vs SiO2 plot classify the granites as high-K calcic alkali to shoshonitic. ANK vs ACNK plot indicatesthey are peraluminous. Plot of A/CNK vs SiO2 and K2O vs Na2O diagrams classified the rock as S-type granite. The granitoids are calc-alkaline with elevated Na2O (>2.6%) and Al/(Na2O+CaO) contents (OGu, 2.1-3.4; OGp, 2.4-3.1 and OGf, 2.2-2.9). The tectonic diagram (Rb vs (Y+Nb) indicatesthatthe batholith is Within Plate Granite (WPG.
Various habitats found on Langkawi Island such as agricultural fields, peat swamps, lowland forests, upland forests, and riverine forests are occupied by many species of anuran fauna. These variations provide a platform to explore species diversity, distribution, and other ecological parameters to understand the distribution patterns and to facilitate the management of important species within particular areas. The objective of this study was to compare species richness of anuran species in different types of habitat on Langkawi Island, Malaysia. We surveyed seven types of habitat, namely agriculture (AG), coastal (CL), forest (FT), pond (PD), fisherman village near estuarine mangrove (FVM), riparian forest (RF), and river (RV). A total of 775 individuals were recorded, representing 23 species from 14 genus and six families known to occur on Langkawi Island. Forest (FT) and riparian forest (RF) (both forest habitats) indicated relatively high values of Shannon Index (H’), 2.60 and 2.38 respectively, compared to the other non-forest habitats, CL (1.82), RV (1.71), FVM (1.56), PD (1.54), and AG (1.53). Rank abundance curves showed that the majority of disturbed habitats displayed geometric series models and broken stick models, whereas forest habitat types (FT and RF) represented log normal models. The performance of species richness estimators varied but Chao 1 estimator performed well for many sampled habitat types and showed the tendency to coalesce with Sobs (Mao Tau) curves except for CL and FVM. As expected, the forested habitat (FT and RF) was more diverse in species diversity compared to those of non-forest groups. Nevertheless, non-forested species were found in abundance, highlighting the relevance of these habitats in supporting the amphibian fauna. This study highlights the importance of habitat types in structuring species diversity and community structures and suggest that the information may be useful to improve conservation practices of inland amphibian habitats.
The volcanic rocks in Temangan, Kelantan consist of felsic to intermediate volcanic rocks, that is mainly of pyroclastic with rhyolitic, dacitic, and andesitic tuff. A geological review has been carried out in Kampung Bukit Besi, Temangan, in Kelantan, Malaysia, which is composed of schist, shale, andesite, and ignimbrite. In Temangan, andesite and ignimbrite show an intimate relationship, as the ignimbrite exists as the fragments and andesite as the matrix. The methodology used in this study are petrography and X-ray Diffraction (XRD) analyses, to determine the mineralogical composition of andesitic ignimbrite. Andesite shows aphenitic and porphyritic textures and consist of pyroxene, plagioclase, alkali feldspar, quartz, biotite and iron oxides. A range of plagioclase textures indicate imperfect equilibrium condition from andesite, reflecting plagioclase dissolution and regrowth. The structural analysis suggest that thrust fault occurred in the study area. Andesite and ignimbrite of the two stages are suggested to have derived from the andesite magma eruption which produced pyroclastic flow eruptions in small amount in most caldera volcanoes at high temperature gradient.
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