Academic literature on the topic 'Malaysian sandstone sediments'

Discrete humus layers are common on podzols under temperate coniferous and tropical heath forests, and patchy layers also occur under some temperate broadleaved forests on non-podzolic soils. We used multiple data sets to test the reported association of humus with oligotrophic but non-podzolic soils under non-heath dipterocarp forest at Lambir, Sarawak. We examined the distribution, morphology and nutrient dynamics of necromass on soils derived from sandstone and shale. Concentrations of the main mineral nutrients were lower in fresh litter on the very oligotrophic sandstone soils than on shale. The rates of litterfall were similar, so that annual litterfall fluxes of all nutrients were lower on sandstone. The lower nutrient concentrations and fluxes in the litter on sandstone resulted in slower decomposition, longer residence times and larger standing crops of forest-floor necromass, with lower concentrations of nutrients. The necromass on sandstone sequestered significantly more N, K and Mg but less Ca and Mn than on shale, with no significant difference for P. The variations in necromass nutrient dynamics were associated with morphological differences. There were mats of densely rooted humus under the litter on sandstone, whereas litter lay directly over the mineral topsoil on shale. Spatial associations with soil nutrients were weak for necromass thickness, but clear for humus. The proportions of nutrients in the litterfall and necromass reflected the stoichiometric profiles of the soils. We attribute the differences in necromass nutrient dynamics and their association with soil reserve nutrients to lower rates of nutrient replenishment from the weathering of sandstone than from shale. Necromass characteristics are robust field indicators of multivariate edaphic differences in these and other tropical forests on Acrisols/Ultisols derived from Tertiary clastic sediments.

Spatial lithofacies and lithofacies association serves as one of the reliable methods in assessing the depositional process of sediments and interpreting its depositional environment. The method of facies analysis is adapted in this study where four newly exposed stratigraphic sections along the Jerantut-Maran road in Jerantut, Central Pahang of Peninsular Malaysia were studied. Previous studies showed that the environment of deposition of these continental deposits is broadly of braided-meandering river. Sedimentological data from the newly exposed stratigraphic sections had given a better understanding on the sedimentation processes involved in these deposits where interpretation on the environment of deposition is construed up to its sub-environment. The main lithofacies recognized include conglomerate, sandstone, and fine-grained facies. The facies associations identified include (i) massive to laminated silt/mudstone, (ii) massive sandstone, (iii) thin to thick ripple to parallel laminated sandstone, (iv) conglomeratic sandstone, (v) graded channelized sandstone, (vi) coarsening upwards medium bedded sandstone and (vii) heterolithic sandstone. The different facies associations are grouped to four (4) facies assemblages showing characteristics of certain environment: (1) floodplain, (2) channel bar complex, (3) point bar and (4) crevasse splay. Floodplain facies assemblage is marked by fine-grained facies, mainly siltstone/mudstone and fine-grained sands with lower flow regime structures. Channel bar complex is identified by high energy deposits of coarse-to-medium grained sandstones often with scoured bottom and lenticular geometry. Point bar is recognized by the lateral accretion surfaces often consisting of normal graded sandstone with sharp top and bottom contact, sometimes capped with thin mudstones. Crevasse splay facies assemblage is characterized by heterolithic sandstone, dominated by flaser-wavy bedding and coarsening upwards medium bedded sandstone that is overlain by fine-grained facies of the floodplain assemblage. The overall facies based on an outcrop scale suggests general features of fluvial facies with fluctuations in flow energy. The environment of deposition is thus interpreted to be of braided river with floodplains and isolated point bar.

Bertangga Formation is a part of the Jurassic-Cretaceous non-marine sequences in Thailand and Malaysia. However, its facies analysis and depositional model have not been investigated in detail. Eleven lithofacies have been described in the Bertangga Formation and combined five facies associations including channel, point bar, floodplain, crevasse splay and swamp facies associations. Channel deposits are stacked bodies of fining upward sequences with prevalent erosional bases, formed by vertical aggradation and avulsion of channels. Point bar sands comprise cross bedded sandstone bodies formed in upper flow regime and possible lateral accretion surfaces. Crevasse splay deposits form sheets of fine-to-medium-grained sandstone. Floodplain sediments are composed of motteled grey mudstone. Swamp depositional environment is characterized by an association of coal, carbonaceous shale and siltstone. Facies analysis allows reconstruction of the depositional environment of the Bertangga Formation as a meandering fluvial system. Facies association also shows the increasingly distal and fine-grained trend from west to east of the studied area, which suggests possible eastward paleo-flow direction of the river. The existence of kaolinite in all samples indicates weathering of felsic rocks under acidic conditions. In the same time, the presence of smectite in the eastern part of the study area may suggest a contribution of mafic and/or volcanic rocks to the source of sediments in this area.

During the feasibility and preliminary design stages of a project, when very little detailed information on the rock mass and its geomechanic characteristics is not available, the use of a Rock Mass Classification Scheme (RMCS) can be of considerable benefit. Various parameters were used in order to identify the RMCS. The parameter comprised of Rock Quality Designation (RQD), Rock Mass Rating (RMR), Rock Structure Rating (RSR), Geological Strength Index (GSI), Slope Mass Rating (SMR), etc. In this paper, we present the results of the applicability of the Geological Strength Index (GSI) classification for the Trusmadi Formation in Sabah, Malaysia. The GSI classification system is based on the assumption that the rock mass contains a sufficient number of “randomly” oriented discontinuities such that it behaves as a homogeneous isotropic mass. In this study, the GSI relates the properties of the intact rock elements/blocks to those of the overall rock mass. It is based on an assessment of the lithology, structure and condition of discontinuity surfaces in the rock mass and is estimated from visual examination of the rock mass exposed in outcrops or surface excavations. A total of ten (10) locations were selected on the basis of exposures of the lithology and slope condition of the Trusmadi Formation. The Trusmadi Formation regionally experienced of two major structural orientations NW-SE and NE-SW. It consists mostly of dark grey shale with thin bedded sandstones, typical of a turbidite deposit. This unit has been subjected to low grade of metamorphism, producing slates, phyllites and meta-sediments and intense tectonic deformation producing disrupted or brecciated beds. Quartz vein are quite widespread within the joints on sandstone beds. The shale is dark grey when fresh but changes light grey to brownish when weathered. The results are classified as “Poor Rock” to “Fair Rock” in term of GSI. The poor categories (TR2 and TR7) represent slickensided, highly weathered surfaces with compact coatings or fillings or angular fragments. It is also characterized as blocky/ disturbed/seamy, which folded with angular blocks formed by many intersecting discontinuity sets. The fair categories can be divided into two (2) types; type 1 (TR1, TR6 and TR8) which represent as smooth, moderately weathered and have altered surfaces. It is also characterised as very blocky rock, which indicates interlocked, partially disturbed ass with multi-faceted angular blocks formed by 4 or more joint sets. Type 2 (TR3, TR4, TR5, TR9 and TR10) which represent as smooth, moderately weathered and have altered surfaces but characterized as blocky/disturbed/seamy, which folded with angular blocks formed by many intersecting discontinuity sets. It also has persistence of bedding planes or schistosity.

In the “flysch” series of the West Crocker Formation (Eocene–Oligocene), Kota Kinabalu, Sabah, trace fossils are fairly common although not ubiquitous. The trace fossils commonly occur as hypichnial semi- or full-reliefs on the sole of thin turbiditic sandstone beds (mainly Bouma Tc division) in the thinly bedded heterolithic sandstone-mudstone facies interpreted as submarine fan lobe deposits. Their presence in mainly the thinly bedded facies of the fan system suggests preferential production and preservation in the fine-grained “distal” parts of the Crocker submarine fan system. Trace fossil assemblages characteristic of the Nereites ichnofacies indicate sedimentary environments mainly in bathyal to abyssal water depths (>2000 m). This ichnofacies is dominated by horizontal grazing, farming and feeding traces, ranging from solitary to branching tubular burrows (Ophiomorpha, Palaeophycus and Planolites) to meandering trails and tunnels (Nereites, Cosmorhaphe, Helminthopsis), as well as the spiriform burrows Spirophycus. Graphoglyptids are the most diagnostic of the Nereites ichnofacies, produced by sediment grazers and farmers (agrichnia) and often displaying intricate networks of mainly horizontal tunnels preserved as hypichnial semi-reliefs. They include the delicate spiral traces of Spirorhaphe, as well as the enigmatic hexagonal network burrow Paleodictyon. Other ichnogenera include Planolites, Thalassinoides and Ophiomorpha which are facies-crossing and not environment specific. Detailed observations of the trace fossil assemblages and the degree of bioturbation enabled different sub-ichnofacies of the Nereites ichnofacies to be distinguished. Ophiomorpha is more common in sandy “proximal” facies and tend to penetrate deeply into pre-existing turbidite beds, its presence suggests a well-oxygenated newly deposited turbidite substrate, probably in the axial region of the fan lobes. Hence, channel axis and proximal fan deposits tend to be dominated by the Ophiomorpha rudis sub-ichnofacies. The Paleodictyon sub-ichnofacies is more typical of the lower energy lobe/fan fringe subenvironments. Proximal but off-axis areas are characterized by a mixture of the Ophiomorpha rudis and Paleodictyon sub-ichnofacies.

Purpose Because of the increasing global oil demand, efforts have been made to further extract oil using chemical enhanced oil recovery (CEOR) methods. However, unlike water flooding, understanding the physicochemical properties of crude oil and its sandstone reservoir makeup is the first step before embarking to CEOR projects. These properties play major roles in the area of EOR technologies and are important for the development of reliable chemical flooding agents; also, they are key parameters used to evaluate the economic and technical feasibilities of production and refining processes in the oil industries. Consequently, this paper aims to investigate various important physicochemical properties of crude oil (specific gravity; American Petroleum Institute [API]; viscosity; pour point; basic sediment and water; wax; and saturate, aromatic, resins and asphaltenes components) and sandstone reservoir makeup (porosity, permeability, bulk volume and density, grain volume and density, morphology and mineral composition and distributions) obtained from Malaysian oil field (MOF) for oil recovery prediction and design of promising chemical flooding agents. Design/methodology/approach Three reservoir sandstones from different depths (CORE 1; 5601, CORE 2; 6173 and CORE 3; 6182 ft) as well as its crude oil were obtained from the MOF, and various characterization instruments, such as high temperature gas chromatography and column chromatography for crude’s fractions identification; GC-simulated distillation for boiling point distribution; POROPERM for porosity and permeability; CT-Scan and scanning electron microscopy-energy dispersive X-ray for morphology and mineral distribution; wax instrument (wax content); pour point analyser (pour point); and visco-rheometre (viscosity), were used for the characterizations. Findings Experimental data gathered from this study show that the field contains low viscous (0.0018-0.014 Pa.s) sweet and light-typed crude because of low sulfur content (0.03 per cent), API gravity (43.1o), high proportion of volatile components (51.78 per cent) and insignificant traces of heavy components (0.02 per cent). Similarly, the rock permeability trend with depth was found in the order of CORE 1 < CORE 2 < CORE 3, and other parameters such as pore volume (Vp), bulk volume (Vb) and grain volume (Vg) also decrease in general. For grain density, the variation is small and insignificant, but for bulk density, CORE 2 records lower than CORE 3 by more than 1 per cent. In the mineral composition analysis, the CORE 2 contains the highest identified mineral content, with the exception of quarts where it was higher in the CORE 3. Thus, a good flow crude characteristic, permeability trend and the net mineral concentrations identified in this reservoir would not affect the economic viability of the CEOR method and predicts the validation of the MOF as a potential field that could respond to CEOR method successfully. Originality/value This paper is the first of its kind to combine the two important oil field properties to scientifically predict the evaluation of an oil field (MOF) as a step forward toward development of novel chemical flooding agents for application in EOR. Hence, information obtained from this paper would help in the development of reliable chemical flooding agents and designing of EOR methods.

The study of the earth mass movement has long been regarded as one of the most important and interesting aspect of engineering geology and geotechnical engineering, which the designers and planners from the private and public sectors address when implementing the initial stage of urban and rural development projects. This involves highways and infrastructures construction and land use planning among the others. Failure to appreciate the problems relating to mass movements of earth material could lead to damage of man made structures and even the loss of lives. These studies focused on the mass movement in Bundu Tuhan to Kundasang highway area approximately 84 km to 96 km from Kota Kinabalu city, Sabah, one of the most vulnerable to mass movements occurrence in west coast of Sabah. It is bounded by longitude line E 116o 31.592’ to E 116o 36.183’ and latitude line N 06o 00.269’ to N 05o 57.610’. The main objectives of this study are; 1) to map and locate the landslides in the study area; and 2) to study the mechanism and the influence of geological factors causing the mass movement. Geology of the study area and its surrounding is hosted mainly by three sedimentary rock formations: Trusmadi Formation (Palaeocene to Eocene age), Crocker Formation (Late Eocene to Early Miocene age) and Pinousuk Gravel (Upper Pleistocene to Holocene age). These three geologic formations dissected by numerous geological lineaments structural produced by a complex tectonic history of multi phase folding and thrust, normal and reverse faulting. These tectonic setting reduce the physical and mechanical properties of the soil and produced intensive displacement in substrata resulting in intensive high degree of weathering processes. The weathered materials are weak and cause sinking, subsidence and sliding due to high pore pressure subjected by both shallow and deep groundwater. Evaluation 10 boreholes data in study area indicated that the groundwater table in study area is shallow and range 1.9 meter to about 11.3 meters. The groundwater in study area fluctuate drastically even within short period. Sand and gravel layer with variable thickness defined the major shallow aquifers within the top weathered materials while the highly fracture sedimentary rocks defined the major deep aquifers. Most of the aquifer within top unconsolidated weathered material is under unconfined condition. Most of significant aquifers within the sedimentary rocks are sandstones. The sandstones generally fracture and contain coarse sediments, which increase the permeability. Geologic and geotechnic evaluation of the study area indicates that the mass movement take place when slope materials are no longer able to resist the force of gravity. These decrease the shear resistance resulting mass movement, which is due to internal and external factors. Internal factors involve some change in either physical or chemical properties of the rock and soil. External factors involve increase of shear stress on slope, which usually involves a form of disturbance that is induced by man. The triggering mechanism in the study area most likely involves heavy rainfall causing water saturation of the slope material and loss of cohesion along rapture planes. The sheared shale, bedding and fault planes, and opening fractures are all structural weaknesses, which acting as pathways for water seepage, hastening the weakening and eventual mass movement in the study area. Development planning has to consider these hazards in order to counter their effect. An environmental management program should be implemented to prevent these losses. Geological and geotechnical studies will play a vital role in ground stability assessment that critical in public safety.

Rock Mass Classification Systems (RMCS) can be of considerable use in the initial stage of a project when little or no detailed information is available. There is a large number of RMCS developed for general purposes but also for specific applications such as Rock Quality Designation (RQD), Rock Mass Rating (RMR), Rock Structure Rating (RSR), Geological Strength Index (GSI), Slope Mass Rating (SMR), etc. In this paper, we present the results of the applicability of the Rock Mass Rating (RMR) System for the Trusmadi Formation in Sabah, Malaysia. The RMR system is a RMCS incorporated with five (5) parameters: Strength of intact rock material, Rock Quality Designation (RQD), Spacing of joints, Condition of joints, and Groundwater conditions. A total of ten (10) locations were selected on the basis of exposures of the lithology and slope condition of the Trusmadi Formation. Trusmadi Formation is Paleocene to Eocene in aged. The Trusmadi Formation generally shows two major structural orientations NW-SE and NE-SW. Trusmadi Formation is characterized by the present of dark colour argillaceous rocks, siltstone and thin-bedded turbidite in well-stratified sequence. Some of the Trusmadi Formation rocks have been metamorphosed to low grade of the greenish-schist facies; the sediment has become slate, phyllite and metarenite. Cataclastic rocks are widespread and occur as black phyllonite enclosing arenitic and lutitic boudins with diameter up to a meter or demarcating thin to thicker fault zones or as flaser zones with hardly any finer grain matrix or as zones of closely spaced fractures. Quartz and calcite veins are quite widespread within the crack deformed on sandstone beds. The shale is dark grey when fresh but changes light grey to brownish when weathered. The RMR system for 10 outcrops ranges from 33.0 to 50.0 and its classified as “Fair” (Class III) to “Poor” (Class IV) rocks. The Fair Rock (Class III) recommended that the excavation should be top heading and bench 1.5 m – 3 m advance in the top heading. Support should be commencing after each blast and complete support 10 m from face. Rock bolts should be systematic with 4 m long spaced 1.5 m – 2 m in crown and walls with wire mesh in crown. Shotcrete should be 50 mm – 100 mm in crown and 30 mm in sides. While for the Poor Rock (Class IV), the excavation should be top heading and bench 1.0 m – 1.5 m advance in top heading. Support should be installed concurrently with excavation, 10 m from face. Rock bolt should be systematic with 4 m – 5 m long, spaced 1.5 m – 1.5 m in crown and walls with wire mesh. Shotcrete of 100 m – 150 mm in crown and 100 mm in sides. The steel sets should be light to medium ribs spaced 1.5 m only when required.