14 research outputs found
Petrology and geochemistry of the Teluk Ramunia volcanics, southeastern Johor,Peninsular Malaysia; implication for middle triassic tectonic / Muhammad Hatta Bin Roselee
No full textThe main objective of this study is to investigate the petrology, geochemistry and
petrogenesis of volcanic rocks from southeast Peninsular Malaysia mainly within Teluk
Ramunia. The volcanic rocks from that area are located on the eastern belt magmatism
dominated by I-type rocks. The rocks from study area are dominated by rhyolite,
trachydacite and diorite and they show irregular contact which suggests
contemporaneous crystallization. Petrographically, all rocks shows occurrence of
microgranophyric, interstitial biotite and hornblende which is characteristic of the Atype
rocks and sub-volcanic emplacement. Field and geochemical evidence shows that
the rhyolite is derived from a different magmatic pulse than trachydacite and diorite.
The value of Ga/A and HFSE (Zr+Nb+Ce+Hf) for all rocks from study area is
comparable to the average A-type rocks. All rocks shows range from metaluminous to
weakly peraluminous in term of their A/CNK value. All rocks from Ramunia yield high
zircon saturation temperature value (826+ 5oC) and high content of high field strength
elements (e.x. Zr,Nb,Ce and Hf) which are clearly indicative of dry source derived or
low pressure incongruent melting. Based on geochemical, petrographical and high
saturation temperature and low pressure (~3.2kbar) calculated from thermometry shows
that all Rock from Ramunia may plausibly derived from low pressure melting of
granodiorite. Based on zircon U-Pb isotope age, rhyolite gave age about 238 + 2 Ma
which suggest that all rocks are related to subduction of the Palaeo-tethys ocean
underneath Indochina (volcanic arc). However the occurrences A-type give implication
that all rocks are formed during crustal extension due to oceanic slab rollback. The
under-plated mantle derived basalt will intrude into the lower to middle crust and
provide sufficient heat to melt the country rocks. The high heat yield by the mantle
derived basalt will contribute to the low pressure incongruent melting of the middle
iv
crust rocks (tonalite and granodiorite) which will formed the A-type magma and
gradually crystallized to be Ramunia volcanics. It is high possible that there are more
occurrence of the A-type rocks throughout Eastern belt province of Peninsular
Malaysia
Petrology and geochemistry of igneous rocks from southern Tioman Island, Pahang, Peninsular Malaysia
No full textThis study reports on the petrology and geochemistry of the plutonic and volcanic on southern part of the Tioman Island. Tioman lies about 50km east of Rompin district, Pahang. The island is dominated by plutonic and volcanic rocks with minor occurrences of metamorphic rock. The plutonic rocks consist of hornblende diorite and biotite granite. The hornblende diorite shows differences in mineralogy and geochemistry when compared to the main diorite body. The volcanics are mostly rhyolite and dacite with exception of andesite on other part of the island. Metamorphic rocks include the andalusite hornfels, quartz pyroxene hornfels, quartzite and amphibolite. Field relationships and published geochronological results indicates that the granite rock intruded both volcanic and diorite rocks during the Late Cretaceous (~80 Ma).The biotite granite post-dates the volcanic rocks by about 8.8Ma. Biotite granite shows slightly older age than the main Tioman diorite by about 1.5 Ma. The geochemistry of the igneous rocks from southern Tioman Island shows that they have a high-calc alkaline affinity which suggests that they are related to arc magmatism
Petrographic and geochemical characteristic of volcanic rocks from Tasik Kenyir and Kampung Awah, East Malaya block, Peninsular Malaysia
No full text
Mineralogical and petrographic characterisation of flake graphite in the graphite mica schist rocks from the Nubian Desert, Sudan
No full textThe Nubian Desert in Sudan, spanning from the Nile River in Wadi Halfa to the eastern Red Sea region, hosts graphite-bearing rocks that can potentially meet the increasing demand for natural graphite, a critical mineral in green energy technologies. This study is the first to investigate the detailed mineralogical and petrographic characteristics of graphite-bearing rocks from this region using petrography, scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The Nubian Desert flake graphite is of high-grade and hosted in metamorphic graphite schist that has been subjected to an increasing regional environment of amphibolite-to-greenschist facies. The schist is of high-grade and fine-grained, with a clear foliation texture composed of graphite (10 %), quartz (35 %), mica (biotite+muscovite) (50 %), and albite (5 %). Fine graphite flakes, ranging from 50 to 150 µm in length with an average width of 46 µm, are disseminated along the schist foliation texture. The quantitative elemental contents are C (10 %), SiO2 (60 %), Al₂O₃ (20 %), and K₂O (10 %). Approximately 84 % of the total carbon is graphite, whereas 16 % is graphitised carbon, which can be upgraded by froth flotation and acid leaching. Although the crystallinity and microcrystal structure of the graphite require further investigation, the preliminary mineralogical features meet the international standards for high-grade fine-flake graphite and suggest its suitability for advanced processing and exploration. These findings highlight the Nubian Desert as an important and underexplored graphite resource, necessitating expanded geological and industrial investigations to meet the growing demand for critical minerals required for sustainable energy technologies
Vestigial Signal of Gondwana to Pangaea Transition: U-Pb and Hf Isotopic Studies on 500-200 Ma Magmatic Zircon from Peninsular Malaysia
No full textGeochemical dispersion of gold-bearing quartz veins in the Wadi Abu Khusheiba area in Southern Jordan
No full textAbstract This study delves into the geochemical dispersion of gold-bearing quartz veins in the Wadi Abu Khusheiba area, southern Jordan, with a focus on uncovering the complex patterns of mineralization and their geological significance. Employing an in-depth geochemical analysis of 24 rock samples from the region, we identified that these samples are predominantly hosted by oversaturated rhyolitic rocks, characterized by high SiO2 content and abundant free Quartz and orthoclase minerals. The mineralized zone of the quartz veins is particularly notable for its gold and silver concentrations, with maximum values reaching up to 5 ppm for gold and 18 ppm for silver. Our investigation into the elemental correlations revealed nuanced relationships, dependent on the 21 sample and analyzed at confidence level of (85%). Contrary to initial assumptions, we did not find a significant positive correlation between gold (Au) and arsenic (As), nor significant negative correlations between gold and other trace elements. These insights are critical for understanding the geochemical behavior of gold in the area and offer a nuanced view of elemental associations. The results of this study are significant for both academic research and practical exploration. They enhance our comprehension of the geological history and mineralization processes in Wadi Abu Khusheiba, providing valuable data that can inform future exploration strategies and deepen our understanding of mineral deposition in similar geological settings. This research not only contributes to the scientific community’s knowledge of the area’s geochemistry but also has potential implications for the mining and exploration industries
Distance impacts toxic metals pollution in mining affected river sediments
No full textThe study of metals mobility derived from mining activities in an ultramafic lithology is limited. This study investigates the effects of distance on potentially toxic metals such as Co, Cu, Fe, Mn, Ni, Pb, and Zn pollution, and the geochemical processes of fluvial system downstream of an ex-copper mine (Mamut River). The toxicity level of the river was evaluated using various sediment quality guidelines, ecotoxicological risks (ecological risk and risk index) and pollution indices. The geochemical behavior and stability of these toxic metals in the solid-phase samples were also examined. The results show that elevated concentrations of Ni, Cu, and Fe in the sediments can be linked to the adsorption and precipitation of metals from the aqueous-phase samples. We found that the metal scavenging rate as a function of distance is more evident in tropical environments than it was previously thought (10 km downstream). Such an inference could be explained by the greater amount of rainfall (pH 5.5–6.5) received in the tropics and higher weathering products that could react and form stable complexes. Geochemical analysis of the river sediment indicates that Ni, Cu, and Fe in the river sediment have increased 44-, 81-, and 90-fold compared to the background values, respectively. A significant decrease in the concentration of the potentially toxic metals was found at 5.5 km downstream. The scavenging rate of Fe is the highest (1485.82 μg g−1 km−1) followed by Cu (141.48 μg g−1 km−1), Ni (10.23 μg g−1 km−1), Pb (8.12 μg g−1 km−1) and Zn (5.01 μg g−1 km−1) in the tropical river system. In contrast, the concentration of Co and Mn in the river sediments doubled as the river flows approximately 5 km downstream due to the higher mineral solubility and weaker metal partition coefficient. This study also discusses the possibility of asbestos (mainly as chrysotile in the X-ray diffraction) as a potential hidden risk present within the ultramafic setting. This case study can be extrapolated to explain the dispersion of inorganic pollutants in an ultramafic environment in a global context
Cenozoic Magmatic Stages in Sumatra and the Incipient of Toba: Zircon Ages and Hf Isotope Evidence
No full textFigure S1: Zircon U–Pb geochronology and Hf isotopic compositions of igneous rocks from Sumatra: implications for the Cenozoic magmatic evolution of the western Sunda Arc
No full textZircon structure where the U–Pb ages from core and rim can be recognized from the CL images of some selected zircons. We chose the younger age to analyse their Hf isotopic ratios
