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Eduard Roca - One of the best experts on this subject based on the ideXlab platform.
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Simulating transport and deposition of Clastic Sediments in an elongate basin using the SIMSAFADIM-Clastic program: The Camarasa artificial lake case study (NE Spain)
Sedimentary Geology, 2009Co-Authors: Oscar Gratacós, Klaus Bitzer, J. L. Casamor, Lluís Cabrera, A. Calafat, Miquel Canals, Eduard RocaAbstract:Abstract Predicting facies distribution and the stratigraphic architecture of Sedimentary basins by process-oriented numerical models is nowadays an essential tool in geologic studies. They constitute a new approach to predict the geologic heterogeneity and the spatial distribution of the diverse facies generated in a depositional system jointly with the distribution of the physical, chemical, and petrophysical characteristics of the Sedimentary deposits in a quantitative way. SIMSAFADIM-Clastic is a 3D process-based, forward numerical model for the simulation of Clastic Sediment transport and Sedimentation in aquatic systems. It simulates the physical process of Clastic transport using the advective, diffusive, and dispersive terms of the transport equation and Clastic Sediment deposition as a result of a variety of processes. The capabilities of SIMSAFADIM-Clastic have been confirmed through the application of the program to a large deep elongated artificial lake, the Camarasa reservoir in the Noguera Pallaresa River, NE of Spain. Simulation results yield Sedimentation rates ranging from 0.04 to 0.09 cm·yr − 1 close to the dam, and from 1.73 to 1.63 cm·yr − 1 in the upper reservoir section. The sample experiment results match well with the observed transport pattern linked to the flow system in Camarasa's reservoir near-bottom water layer, which transports more than 50% of the Sediment that is supplied to the reservoir. Opening and closure of turbine gates and the basin geometry are the main controlling factors on the fluid flow and depositional pattern in the reservoir, with a more diversified pattern obtained when an open boundary is defined. However, the resulting model also shows some limitations of the program as it does consider a stratified water column that is consistently observed in the reservoir. Refined modeling exercises of the type described in this paper are of potential application to predict and quantify Sedimentation patterns allowing the implementation of efficient preservation measures against reservoir siltation.
Peter S Roy - One of the best experts on this subject based on the ideXlab platform.
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heavy mineral beach placers in southeastern australia their nature and genesis
Economic Geology, 1999Co-Authors: Peter S RoyAbstract:Southeastern Australia has been one of the world's most productive heavy mineral sand provinces. Concentrations of detrital rutile, zircon, ilmenite, and minor monazite occur as beach placers and in dunes in high-stand barriers of Quaternary age along the present coast. Although individual mineral grains are of terrigeneous origin, the heavy mineral deposits themselves are not linked to specific source rocks in the hinterland. Rather, they arise under the action of waves during the building of coastal sand barriers. A number of fractionating mechanisms that concentrate heavy minerals operate during marine transgressions and under highstand conditions to produce three different types of beach placers. Type A deposits occur along erosional discontinuities in leaky embayments or between barriers of different age. Here, repeated storm reworking has produced beach face concentrations on drift-aligned sectors of coast by a process termed "littoral bypassing fractionation." Type B heavy mineral deposits are found in back-barrier washover facies (and sometimes as condensed sections) at the rear of swash-aligned barriers in coastal embayments. These were produced by a process of transgressive barrier fractionation that reworked heavy minerals from shelves undergoing erosion during marine transgressions. Type C heavy mineral deposits occur in prograded barriers and represent episodic influxes of remobilized heavy mineral-rich sand that originated elsewhere through the two fractionation mechanisms mentioned above. Necessary environmental conditions for these fractionating mechanisms to operate include: low rates of Clastic Sediment supply and long periods of weathering and abrasion to create a mature heavy mineral suite, an energetic swell wave climate driving large sand fluxes onshore and alongshore, and changing sea levels (especially marine transgressions) that have the effect of moving heavy minerals from the shelf onto the present coast. Because of the last-mentioned effect, the mineral prospectivity for the southeastern Australian continental shelf is not high.
David L Dunkerley - One of the best experts on this subject based on the ideXlab platform.
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Discussion: Bulk sampling of coarse Clastic Sediments for particle-size analysis
Earth Surface Processes and Landforms, 1994Co-Authors: David L DunkerleyAbstract:Gale and Hoare (1992) have provided a figure relating maximum particle diameter in a coarse Clastic Sediment to the size of sample required to generate a reproducible measure of the particle-size distribution of that Sediment. However, they fail adequately to justify the basis for the criterion of sample adequacy adopted in their proposal. Additionally, there is a range of separate issues neglected by Gale and Hoare (1992) which makes their conclusion inapplicable in many situations. A fundamental issue that they neglect is the purpose lying behind a grain-size analysis: this issue determines what grain size measures are appropriate, rather than the empirical, seemingly purpose-independent, approach of Gale and Hoare (1992).
Liu Changzheng - One of the best experts on this subject based on the ideXlab platform.
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zircon u pb ages of Clastic Sediment from the outfall of the yellow river and their geological significance
Geoscience, 2013Co-Authors: Liu ChangzhengAbstract:Terrigenous Clastic Sedimentary rocks(Sediments) are natural mixture of their provenance materials,preserving important information of different processes on their provenances,which can usually be used as key clues of processes of basin Sedimentation,regional tectonic,crustal growth and evolution,and reconstruction of ancient continent.Zircon U-Pb age studies of river sand from the outfall of the Yellow River in Dongying,Shandong Province,together with grain size analysis of detrital components and constituent of heavy minerals,show that the main size of river sand in the outfall of the Yellow River ranges from 10 to 280 μm.Heavy minerals are composed of hornblende,hematite-limonite,garnet,epidote,magnetite,etc.Detrital zircons in the outfall of the Yellow River are igneous origin with multiple populations of ages.The maximum concordant U-Pb age is～3.65 Ga,which reflects the existence of over 3.6 Ga crustal material in the other areas apart from Anshan,Liaoning Province and eastern Hebei Province.Zircon ages mainly distribute in 206-440 Ma,843-1,239 Ma,1,476-2,714 Ma,peakings at ～2.5 Ga,～1.8 Ga and 400 Ma.The two peaks of around ～2.5 Ga and ～1.8 Ga show contribution of the North China Block.The 400 Ma peak and ages between 1,000 and 800 Ma represent input materials that came from the Su-Lu Orogenic Belt.Together with previous studies,2.5-1.8 Ga should be the main growth stage of continent for the provenance crust of the Yellow River's draining area,and over 60% crust was formed at that time.
Peter G. Hoare - One of the best experts on this subject based on the ideXlab platform.
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Reply: Bulk sampling of coarse Clastic Sediments for particle‐size analysis
Earth Surface Processes and Landforms, 1994Co-Authors: S. J. Gale, Peter G. HoareAbstract:The work of Gale and Hoare (1992) provides a guide to the minimum mass of bulk sample required to obtain a reproducible measure of the complete particle-size distribution of coarse Clastic Sediments such as till, fluvial gravel and beach gravel. Dunkerley (1994) makes a number of criticisms and misrepresentations of this procedure. These are systematically refuted and corrected here, and further data obtained from till and beach gravel are provided to support the criterion adopted by Gale and Hoare (1992) for sample reliability. The procedure of Gale and Hoare (1992) is confirmed as a practical guide to the mass of bulk sample required to obtain a reliable measure of the particle-size distribution of coarse Clastic Sediment.