Kamal Roslan Mohamed

Late Triassic Radiolaria from the Kodiang Limestone, northwest Peninsular Malaysia

Abstract Two different cherty packstone-wackestone facies are exposed at an abandoned limestone quarry at Bukit Kodiang, Kedah. Chert occurs as discontinuous layers and nodules in the cherty packstone-wackestone. The thickness of individual chert layers varies from 2 to 10 cm. The facies exhibit slump folds. Eighteen species of Radiolaria were identified—Capnuchosphaera triassica De Wever, Triassocampe sulovensis Kozur and Mock, Tetraporobrachia asymmetrica Kozur and Mostler, Xenorum flexum Blome, Canoptum laxum Blome, Palaeosaturnalis triassicus Kozur and Mostler, Canoptum cf. farawayensis Blome, Pseudostylosphaera cf. spinulosa Nakaseko and Nishimura, Hagiastrum cf. augustum Pessagno, Perispongidium sp., Capnuchosphaera sp., Sarla sp., Kahlerosphaera sp., Canoptum sp., Latium sp., Paronaella sp., Sontonaella sp., and Spongostylus sp. The assemblage indicates that the age of the chert bearing strata ranges from late Carnian to middle Norian, Late Traissic.

Benthic Foraminiferal Assemblages in the Pahang River Delta (Pahang, Malaysia)

Sixty-six surface sediments were collected to investigate the species composition and distribution patterns of living and dead benthic foraminifera from the Pahang River Delta (east coast Peninsular Malaysia). The foraminiferal assemblages comprised 50,411 individuals from 30 families (88 species within 50 genera) in the study area. Agglutinated foraminifera were dominant at the river mouth area while calcareous species dominated the offshore sampling sites. By using Q-mode cluster analysis, four faunal assemblages were associated with distant water depths and sediment substrates. The first assemblage, dominated by Asterorotalia pulchella, was present from the station with the highest abundance amongst the other stations in the study area from the water depths <15 m and associated with silty sand substrate. The second assemblage was mostly dominated by larger foraminifera that occurred at the deeper parts of the study area with mostly sand substrate. The third assemblage consisting of the agglutinated species Ammobaculites exiguus, occured in the river mouth at water depths less than 10 m and was associated with high content of silt and clay substrate. The fourth assemblage was dominated by the agglutinated species Ammonia and Elphidium and occurred at the shallow parts of the study area with fine sand and sandy mud substrate. Considering the above, the assemblage clustering suggests that the distribution patterns of benthic foraminifera in the study area were strongly influenced by water depth and type of sediment substrate.

Geological heritage assessment for sustainable development of Lenggong Valley

The quantitative methodology for assessment of geosite can be used for the sustainable management and conservation of geological heritage of an area. The main aim of this paper is to develop the methodology for identification, characterization and evaluation of every geosite based on the quantitative assessment. This early stage of evaluation discussed on criteria that cover all value sets and its potential of used. Value sets take into account the scientific value, cultural value, ecological value, aesthetic value and economic value, respectively. The total scores based on quantitative analysis will be used to determine the ranking of the geosite. Following the description of the proposed method, the paper presents the assessment results of thirteen selected geosite in the Archaeological Heritage of Lenggong Valley.

Microfacies and diagenesis of Gua Bama limestone, Pahang Darul Makmur, Malaysia

Gua Bama limestone hill in Lipis District, Pahang State is a well-known site for the hunt of Malaysian Permo-Triassic Boundary. This paper details the microfacies and diagenesis of limestone succession at Gua Bama outcrop as an early effort to constrain the desired Permo-Triassic Boundary. Six microfacies have been identified: mudstone, peloidal wackestone, bioclastic wackestone, radiolarian wackestone, intraclastic packstone, and peloidal packstone. The appearance of highly diverse benthic fauna in fragmented forms and the dominance of mudstone-wackestone microfacies prove that carbonates of Gua Bama were deposited in low-energy shallow marine environment. Gua Bama have been subjected to multiple diagenetic processes, namely cementation, compaction, neomorphism, and micritization. Based on diagenetic textures observed, it can be interpreted that Gua Bama limestone had undergone diagenesis within marine water phreatic zone and deep burial realms.

Delta zoning based on sediment dispersal in Pahang River Delta

Rapid deposition and suspended sediment dispersal off the Pahang River mouth has been examined by collecting 57 samples around Pahang River Delta. The results show that Pahang River Delta can be divided into four zones which are distributary mouth bar, delta front, pro-delta and platform or shelf. Grain size analysis can be used in order to determine zones of deltaic deposition. Most rapid deposition and deposition of the coarsest material takes place in a short distance from the river mouth, a sand body commonly referred to a distributary mouth bar. The average percentage of sand, silt and clay of this zone are 77 %, 17 % and 4 %, respectively. Seaward of this region, percentage of sand diminished rapidly where a zone of inter-fingering sands, silt and clay are commonly found. This zone is commonly referred as delta front deposits where the average percentage of sand, silt and clay for this zone are 47 %, 46 % and 6 %, respectively. Beyond the delta fronts, only fine silt and clay remain in suspension an...

Dolomites petrography and geochemistry of the Chuping Formation, Malaysia

Detailed petrographic and geochemical studies had been done to 89 samples from the Chuping Formation collected at Bukit Tengku Lembu area. The aim of this paper is to document the nature of dolomitization and its petrographical characteristics. Two types of dolomites have been recognized; stratified dolomites and non-stratified dolomites. Non-stratified dolomites can be further divided into complete-replacing dolomites, individual-scattered dolomites and selective-replacing dolomites. The geochemical data from X-ray Fluorescence analysis detected low concentrations of trace elements which includes Al, Fe, K, Mn, Na, P, Si, Sr and Ti, with a high Ca/Mg ratio ranging from1.681 mol to as high as 106.942 mol. This big fluctuation in values indicates a variation of fluids that are involved in the diagenetic processes. Individual-scattered dolomites have perfect rhombus shape with no evidence of being affected by compaction and pressure indicating a shallow burial setting. Meanwhile presence of perfect saddle dolomites with replacive nature and no signs of being affected by compaction, also suggested late burial settings, in which compaction ceased. High Ca/Mg ratios may also suggest some dedolomitization effects.