13 research outputs found

    Ce anomaly in I‒type granitic soil from Kuantan, Peninsular Malaysia: retention of zircon in the weathering product

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    This paper describes the Ce anomaly observed in granitic soil from the humid, tropical area of Kuantan, Pahang, Peninsular Malaysia. Three granite rock soil profiles from Kuantan, were sampled and all samples were analysed for rare earth elements. All the profiles of the granitic soil samples show prominent positive Ce anomalies, with the Ce/Ce* ratio values (Ce/Ce*= CeN/√LaN.PrN) ranging from 1.2 to 125. l. Ce4+ is compatible in zircon because it has also the same charge and a similar ionic radius as to Zr4+ (Ce4+ = 0.97 Å; Zr4+ = 0.84 Å). The retention of zircon in the weathering product of the granitic rocks will increase the Ce content in the soil. Thus it is likely that the positive Ce anomaly in the REE profile of the Kuantan Granites may also have resulted from retention of zircon in the weathering product

    Facies analysis of the Uppermost Kubang Pasu Formation, Perlis: a wave-and storm-influenced coastal depositional system

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    A detailed sedimentological study and facies analysis of the Permian age, uppermost succession of the Kubang Pasu Formation in Perlis was conducted in order to reconstruct the palaeo-depositional environment. Four stratigraphic sections of the uppermost Kubang Pasu Formation were logged at Bukit Chondong and Bukit Tungku Lembu, Perlis. The sections were divided into facies based on lithology and sedimentary structures. Large scale patterns in the form of facies associations and facies successions were also identified. The uppermost Kubang Pasu Formation can be divided into several coarsening upward facies successions. Each facies succession grades upward from an offshore facies association (FA1) composed of bioturbated mudstone and minor thin sandstone, into a distal lower shoreface facies association (FA 2) composed primarily of mudstone interbedded with hummocky cross-stratified sandstone (HCS) and finally a proximal lower shoreface facies association (FA 3) composed of amalgamated hummocky cross-stratified sandstone beds. The facies succession is interpreted as representing a wave- and storm-influenced coastal depositional environment. The gradual transition from siliciclastics to carbonates is probably related to post rift thermal subsidence and tectonic quiescence due to separation of Sibumasu from Gondwana during the Permian

    A deep marine origin for the Tajau Sandstone member of the Kudat Formation, Kudat Peninsula, Sabah: evidence from facies analysis and ichnology

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    There have been many disagreements regarding the depositional environment of the Oligocene Tajau Sandstone Member of the Kudat Formation, Northern Sabah. We present here, the first detailed sedimentary facies analysis for the Tajau Sandstone Member, exposed on the Kudat Peninsula. The identified facies are interpreted as the deposits of subaqueous sediment density flows, which are common processes in deep marine depositional settings. These include debrites, hyperconcentrated density flow deposits, and turbidites. Several of the turbidite facies display evidence for hydraulic jumps, which are also common processes in deepwater settings and probably indicate changes in slope topography or loss of flow confinement. Trace fossils characteristic of the Nereites ichnofacies are also diagnostic of a deep marine depositional environment. Facies previously identified by previous workers as hummocky cross-stratification in the Tajau Sandstone Member, which was used to support a shallow marine interpretation, is better interpreted as supercritical antidunes developed in high density turbidites, based on the coarse-grained texture, spaced layering and association with other subaqeuoues density flow deposits

    A deep marine origin for the Tajau sandstone member of the Kudat formation, Kudat Peninsula, Sabah: evidence from facies analysis and ichnology

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    There have been many disagreements regarding the depositional environment of the Oligocene Tajau Sandstone Member of the Kudat Formation, Northern Sabah. We present here, the first detailed sedimentary facies analysis for the Tajau Sandstone Member, exposed on the Kudat Peninsula. The identified facies are interpreted as the deposits of subaqueous sediment density flows, which are common processes in deep marine depositional settings. These include debrites, hyperconcentrated density flow deposits, and turbidites. Several of the turbidite facies display evidence for hydraulic jumps, which are also common processes in deepwater settings and probably indicate changes in slope topography or loss of flow confinement. Trace fossils characteristic of the Nereites ichnofacies are also diagnostic of a deep marine depositional environment. Facies previously identified by previous workers as hummocky cross-stratification in the Tajau Sandstone Member, which was used to support a shallow marine interpretation, is better interpreted as supercritical antidunes developed in high density turbidites, based on the coarse-grained texture, spaced layering and association with other subaqeuoues density flow deposits

    Digital core analysis: Improved connectivity and permeability characterization of thin sandstone layers in heterolithic rocks

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    Heterolithic thin beds reservoirs contain significant amounts of hydrocarbons. We characterized the reservoir properties (sandstone connectivity, continuity and permeability) of sandstone layers in heterolithic rocks using three-dimensional imaging and analysis of heterolithic core plugs and mini plugs. The high-resolution three-dimensional models of the samples are smaller than a typical reservoir model grid block and similar the millimetre-to-centimetre beddings in heterolithic rocks. We find that the key to reservoir quality in heterolithic rocks is the connectivity and continuity of thin reservoir sandstone layers. Also, we show that these well connected and continuous thin sandstone layers have higher effective permeabilities that are comparable to a reference reservoir sandstone. These results can provide further information as to why some low resistivity heterolithic intervals with low net-to-gross values of the sandstone produced a significant amount of hydrocarbon despite lower production forecast based on well logs and core plug data. Determining the connectivity and continuity of thin sandstone layers is difficult due to limitations of well logs and core plug analysis that do not resolve and capture the connectivity of thin beddings. We show that 3-D Image Visualization is effective in characterizing the connectivity and continuity of thin sandstone layers in heterolithic rocks. Also, our Digital Core Analysis method computed permeability of thin sandstone layers in 3-D models of mini plugs representing thin sandstone layers in heterolithic core plugs. Our results represent information and reservoir properties at the millimetre-to-centimetre scale that are similar to the thickness of thin sandstone beddings in heterolithic rocks.The study was supported by the Universiti Malaya Research Grant RP031A-15AFR and FP045-2017A and was conducted at the Australian National University under a Dual PhD program arrangement with Universiti Malaya. PETRONAS, the Malaysian National Oil Company, is acknowledged for providing the core samples used in this stud

    Impact of agricultural land use on physicochemical properties of soils derived from sedimentary rocks in Malaysia

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    In Malaysia, soils derived from sedimentary rocks are extensively used for agricultural purposes with oil palm and rubber being the main dwellers. In order to understand the environmental impact of these perennial crops planting, the variability of physicochemical properties of 25 representative soils derived from sedimentary rocks under different ecosystems (agriculture land and natural forest) at six study sites spread across Malaysia was examined. Among the soil physicochemical properties, total soil organic carbon, total nitrogen, and fertility level were found to be generally higher in the forest ecosystems followed by rubber plantation and finally oil palm plantations. Likewise, projection of principal component analysis showed an associative relationship between soil physicochemical properties and microhabitats. Finally, this study showed that soils from different agricultural and natural sites, but derived from similar sedimentary rocks, had distinctive weathering conditions and soil properties. Therefore, site-specific field management according to soil type, soil management techniques as well as fertilizer strategies are required to maximize crop production and to sustain ecosystem services. The output of this study will enable farmers to improve their crop yield via the selection of suitable crops cultivation based on soil characteristics

    Assessment of heavy metal pollution in surficial sediments from a tropical river-estuary-shelf system: A case study of Kelantan River, Malaysia

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    To understand the source-to-sink of pollutants in the Kelantan River estuary and the adjacent shelf area in Malaysia, a total of 42 surface sediment samples were collected in the Kelantan River-estuary-shelf system to analyze for grain size, total organic carbon (TOC) content, Al and heavy metals (Cr, Ni, Cu, Zn, Cd and Pb). The surficial sediments were mainly composed of clayey silt and the TOC content in sediments decreased from the river to the shelf. The surficial sediments experienced Pb pollution; Cr only showed a certain level of pollution in the coastal area of the estuary but not in other areas, and Ni, Cu, Zn, and Cd showed no pollution. The heavy metals mainly originated from natural weathering and erosion of rocks and soils in the catchment and enriched near the river mouth. Total organic carbon can promote the enrichment of heavy metals in sediments
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