Journal ArticleDOI
Anatomy and Stratigraphic Development of a Basin Floor Turbidite System in the Laingsburg Formation, Main Karoo Basin, South Africa
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In this article, the lowermost 300 m thick Fan A-F turbidite system was studied and the facies associations include channel fills and correlative lateral overbank deposits of thin sheet-like and rippled sandstones.Abstract:
Six individual turbidite systems, informally called Fans A-F, were deposited in the Laingsburg area of the southwestern Karoo Permian foreland basin. This study concentrates on the lowermost, 300 m thick "Fan A" system. Facies associations include channel fills and correlative lateral overbank deposits consisting of thin sheet-like and rippled sandstones. Massive- and thin-bedded frontal sheet sandstones form down-dip extensions to channel systems. Identification and correlation of mudstone-dominated intervals from field mapping and oblique aerial photostratigraphy delineates a high-resolution internal stratigraphy of the fan system which, coupled with 4000 m of logged section, allows detailed geometrical and architectural analysis. Seven individual depositional units have been mapped within Fan A, and these are interpreted as the deep-basin sedimentological expressions of high-frequency lowstand systems tracts, separated by high-frequency transgressive and highstand condensed intervals. Stacking patterns of the seven lowstand fan units that make up Fan A record early progradation (units 1 to 3), a backstep (unit 4), followed by further progradation (units 5 and 6). Retrogradation during unit 7 records abandonment of the whole Fan A deposystem. Coupled with facies analysis, paleocurrents reveal unusual paleotransport patterns that are interpreted as a consequence of structural deformation of the basin floor. Paleotransport indicators reveal that sediment pathways are strongly parallel to the structural grain, while some point to sediment pathways that crosscut the dominant structural grain.read more
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Journal ArticleDOI
Sequence stratigraphy: methodology and nomenclature
Octavian Catuneanu,William E. Galloway,Christopher G. St. C. Kendall,Andrew D. Miall,Henry W. Posamentier,André Strasser,Maurice E. Tucker +6 more
TL;DR: In this article, a standard but flexible methodology is proposed to analyze stratal stacking patterns in a sequence stratigraphic unit, from sequence to systems tract and parasequence.
Journal ArticleDOI
Evolution, architecture and hierarchy of distributary deep-water deposits: a high-resolution outcrop investigation from the Permian Karoo Basin, South Africa
TL;DR: A detailed study of a single-lobe complex (Fan 3) over a 15 km by 8 km area has helped to define a four-fold hierarchy of depositional elements from bed through to lobe element, lobe and lobe complex as mentioned in this paper.
Journal ArticleDOI
Tectonic evolution of the Cape and Karoo basins of South Africa
TL;DR: The early Paleozoic Cape basin records the combined effects of a north-dipping intra-crustal decollement (a late Neoproterozoic suture) and a right-stepping offset between thick Rio de la Plata craton and Namaqua basement.
Journal ArticleDOI
Sedimentological criteria to differentiate submarine channel levee subenvironments: Exhumed examples from the Rosario Fm. (Upper Cretaceous) of Baja California, Mexico, and the Fort Brown Fm. (Permian), Karoo Basin, S. Africa
Ian A. Kane,David M. Hodgson +1 more
TL;DR: In this paper, a suite of characteristic sedimentary features are recognized from internal and external levees respectively: internal levees are characterised by structures indicative of complexity in the waxing-waning style of overspill, interactions with topography and flow magnitude variability; in contrast, external levees are characterized by simple surgelike waning flows, relatively uniform flow directions, laterally extensive beds, and a lack of erosive events.
Journal ArticleDOI
Stratigraphic Evolution of Fine-Grained Submarine Fan Systems, Tanqua Depocenter, Karoo Basin, South Africa
David M. Hodgson,Stephen S. Flint,David Hodgetts,Nicholas J. Drinkwater,Erik P. Johannessen,Stefan M. Luthi +5 more
TL;DR: In this paper, a model of the stratigraphic evolution of four Permian fine-grained submarine fan systems (Fans 1-4) from the Tanqua depocenter, SW Karoo Basin, South Africa is presented.
References
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Journal ArticleDOI
Chronology of fluctuating sea levels since the triassic.
TL;DR: An effort has been made to develop a realistic and accurate time scale and widely applicablechronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework.
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Sediment Gravity Flows: II Depositional Models with Special Reference to the Deposits of High-Density Turbidity Currents
TL;DR: In this article, sediment deposition from individual sediment flows commonly involves more than one of these mechanisms acting either serially as the flow evolves or simultaneously on different grain populations, and the effects of hindered settling, dispersive pressure, and matrix buoyant lift are con entration dependent.
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High-frequency sequences and their stacking patterns: sequence-stratigraphic evidence of high-frequency eustatic cycles
TL;DR: A hierarchy of interpreted eustatic cyclicity in siliciclastic sedimentary rocks has a pattern of superposed cycles with frequencies in the ranges of 9-10 my, 1-2 my, 01-02 my, and 001-002 my (second- through fifth-order cyclicity, respectively) as discussed by the authors.
Book
The geology of stratigraphic sequences
TL;DR: In this article, the authors discuss the importance of sequence stratigraphy in geology, and propose a sequence-based model for the analysis of cyclic cycles with millions of years.
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Suspended‐load fallout rate as an independent variable in the analysis of current structures
TL;DR: The results of these and related studies have been used to construct stability field diagrams in which the fields of individual bedforms are usually expressed as a function of flow intensity (power, velocity, bed shear stress, etc.) and grain size as mentioned in this paper.