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Salut-Mengabong Lagoon is located at the west coast of Sabah facing the South China Sea. At the bay side of the main inlet the lagoon splits into Salut and Mengabong Channels. Sediment dynamics at the inlets of the lagoon have recently received considerable attention. But any direct measurement of hydrodynamics and sediment flux are yet to be well documented. This study covers the field measurements of current velocity, water flux, suspended sediment concentration and sediment flux across the three transects (main inlet, Salut entrance and Mengkabong entrance) during typical spring and neap tidal cycles in southwest monsoon and northeast monsoon. Temporal variations and time-averaged values of measured parameters are discussed. The inlets of Salut-Mengkabong Lagoon are found to be ebb-dominated. The time-averaged velocities during spring tidal measurements are found to be higher in the main inlet followed by Mengkabong entrance and Salut entrance. Suspended sediment concentration and sediment fluxes are substantially higher in spring tidal cycles compared to the same in neap tidal cycles. During spring tidal cycles, ebb tidal sediment fluxes are higher than the flood tidal fluxes. The ebb dominated flux across the main inlet led to the large ebb shoal. 相似文献
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Outcrop and microscopic studies have been applied in this research paper in order to find out the Asmari Formation depositional sequences in the Shajabil Anticline section located at the north of the Izeh Zone,Zagros Basin,Iran.Five depositional sequences were identified based on 11 facies types （bioclast Nummulitidae Lepidocyclinidae packstone,bioclast perforate foraminifera Nephrolepidina Miogypsinoides wackestone-packstone,bioclast perforate foraminifera Corallinacea wackestone-packstone,bioclast echinoid Neorotalia Brachiopoda wackestone-packstone,coral floatstone-rudstone,bioclast Corallinacea imperforate foraminifera wackestone-packstone,bioclast imperforate foraminifera Archaias wackestone-packstone,bioclast imperforate foraminifera Dendritina wackestone-packstone-grainstone,bioclast imperforate foraminifera Borelis wackestonepackstone and very fine sandy mudstone） corresponding to the tidal flat,restricted and semirestricted lagoon and open marine environments of an inner and middle shelf areas.Well-exposed outcrop horizons of Thalassinoides at the study section are a favorable tool for the regional outcrop sequence stratigraphy.Thalassinoides is considered as an outcrop key-bed for recognition of the Rupelian-Chattian maximum flooding depositional sequence.Coral remnants （small colonies） in outcrop exposures also are associated with the HST depositional sequence （Chattian） for the Asmari Formation.The most important achievement of this research is use of associated maximum flooding surfaces （Pg30,Pg40,Pg50,Ngl0 and Ng20） in the Arabian plate.These maximum flooding surfaces could be recorded as an isochrones surface. 相似文献
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Calcium-poor dolomite from the sabkhas of Kuwait 总被引：1，自引：0，他引：1
Small quantities of a rare Ca-deficient dolomite have been found coexisting in thin layers and alternating with the normal Ca-rich variety in the Holocene sabkhas of southern Kuwait. The Ca-poor dolomite has a molar composition of Ca46–49, whereas the Ca-rich type is Ca51–56. The former type has been found only in two localities of the supratidal zone that are not subjected to tidal flooding today, and mostly within the fluctuating ground-water table in these zones. The thin layers are either carbonate mud-rich or pellet-rich, and the amount of Ca-poor dolomite is never more than 4 to 6 per cent by weight of the total carbonate fraction. The dolomites vary in size between 2 μm and 5 μm and exhibit characteristic rhombic crystal morphologies. 相似文献
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Deducing sediment transport direction and the relative importance of rivers on a tropical microtidal beach using the "McLaren model" 总被引：1，自引：0，他引：1
H. Mohd-Lokman Y. Rosnan S. Ejria N. A. M. Shazili K. K. Y. Kassim 《Environmental Geology》1998,34(2-3):128-134
Analyses of the sedimentological trend from 90 samples collected at 1-km intervals along a tropical microtidal coastline
of northern Terengganu indicate that the preferred sediment transport direction was northwards, following the McLaren model.
The extent of disruption to and reestablishment of the sedimentological trend on beaches north of two river mouths within
the study area was used to determine their relative importance in supplying sediment to the beaches. The extent of disruption
to the sedimentological trend was 18 and 14 km for the beaches north of the Terengganu and Setiu River mouths, respectively.
This suggests that the Terengganu River is more important in supplying sediments to the beach than the Setiu River. To a limited
extent this study showed that the McLaren model can be applied to deduce sediment transport direction on a microtidal coastline,
while disruption to the sedimentological trend adjacent to river mouths can be used to compare the relative importance of
rivers in supplying sediments, provided that the disruption to the sedimentological trend is small enough so as to allow for
the trend to be discernible again further along the transport path.
Received: 8 May 1997 · Accepted: 12 August 1997 相似文献
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