Origin of hummocky and swaley cross-stratification— The controlling influence of unidirectional current strength and aggradation rate

Dumas, Simone; Arnott, R. W. C.

doi:10.1130/g22930a.1

Cited by 418 publications

(315 citation statements)

References 21 publications

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“…(Kiefer, 1995;Kazmierczak and Altermann, 2002), this facies should rather be interpreted as deep subtidal, reflecting below-fair-weather-wave base deposition, in a restricted, rapidly subsiding and filled basin, under the influence of relatively proximal lapilli, accretionary lapilli and ash tuff volcanic input (Altermann, 1996); additionally, seismic activity is documented by the V-shaped cracks formed in the semi-consolidated limestones. This interpretation is consistent with tempestitic deposition and hummocky structures (Dumas and Arnott, 2006) in tuffs and tuffites. Thus the samples described by Kazmierczak and Altermann (2002) and the new samples collected for this study, should be considered to reflect accumulation of organic-rich calcareous shales, flat pebble breccias, conglomerates and platy carbonates in a subtidal rather than a peritidal setting, probably below fair weather but above the storm wave base.…”

Section: Geological Settingsupporting

confidence: 78%

Mass occurrence of benthic coccoid cyanobacteria and their role in the production of Neoarchean carbonates of South Africa

Kaźmierczak

Altermann

Kremer

et al. 2009

Precambrian Research

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a b s t r a c tThe sparse Archean fossil record is based almost entirely on carbonaceous remnants of microorganisms cellularly preserved due to their early post-mortem silicification. Hitherto as an exception, sedimentary carbonate rocks from the Neoarchean Nauga Formation of South Africa contain calcified microbial mats composed of microbiota closely resembling modern benthic colonial cyanobacteria (Chroococcales and Pleurocapsales). Their remains, visible under the scanning electron microscope (SEM) after etching of polished rock samples, comprise capsular envelopes, mucilage sheaths, and groups of cells mineralized by calcium carbonate with an admixture of Al-K-Mg-Fe silicates. The capsular organization of the mucilaginous sheaths surrounding individual cells and cell clusters forming colonies and the mode of mineralization are the characteristic common features of the Neoarchean microbiota described and their modern analogues. The new findings indicate massive production of calcium carbonates by benthic coccoid cyanobacteria in the Neoarchean, and offer a solution to the problem of the origin of Archean carbonate platforms, stromatolites and microbial reefs.

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Section: Geological Settingsupporting

confidence: 78%

Mass occurrence of benthic coccoid cyanobacteria and their role in the production of Neoarchean carbonates of South Africa

Kaźmierczak

Altermann

Kremer

et al. 2009

Precambrian Research

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“…Hummocks form below the fair weather wave base and above, but are most common near storm weather wave base (Dumas & Arnott, 2006). Erosive based, very-fine to fine-grained sandstones characterised by abundant soft-sediment deformation.…”

Section: 'S M)mentioning

confidence: 99%

“…Wave ripples shallow into current ripples, but can be reworked by storm events resulting in hummocky cross-stratification (Reading & Collinson, 1996;Dumas & Arnott, 2006). Interbedded mudstones and mud drapes are indicative of alternating energy conditions and could also be attributed to a tidal influence (Davis, 2012).…”

Section: Descriptionmentioning

confidence: 99%

Facies development of the Upper Triassic succession on Barentsøya, Wilhelmøya and NE Spitsbergen, Svalbard

Lord¹,

Johansen²,

Støen³

et al. 2017

NJG

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Field data collected from the northeasternmost Triassic exposures on the islands of Spitsbergen, Wilhelmøya and Barentsøya during 2015 are used for sedimentological facies analysis to improve our understanding of the stratigraphic development of the Upper Triassic strata. Results presented here build upon previous studies from the eastern areas of the Svalbard archipelago and seek to extend this understanding northward. Paralic deltaic sediments are recognised throughout the field area, and our analysis shows that the Upper Triassic De Geerdalen Formation is composed of three discrete units defined by the differences in gross depositional environments. The lower interval of early Carnian age is dominated by shallow-marine and delta-front/ shoreface deposits, the middle interval of mid Carnian age is dominated by delta-front to delta-top deposits, and the upper interval, corresponding to the Isfjorden Member, of a late Carnian to early Norian age, is dominated by delta-top deposits which include lagoonal and lacustrine deposits. These observations show that the De Geerdalen Formation represents a more distal depositional setting, than the depositional environments previously reported from the islands of Edgeøya and Hopen. We also document the presence of the Tschermakfjellet Formation and Isfjorden Member on Wilhelmøya, thus increasing our understanding of the northwestward development of the Upper Triassic succession in Svalbard.

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“…The importance of the erosional incisions reaching locally lowermost units pleads in favor of relatively important hydrodynamic energy within the sedimentation area. The characteristics of the two-dimensional vortex ripples with a complex geometry of the sets of cross laminae in TCS suggest the action of waves with relatively small orbital velocity, as hummocky cross stratification (HCS) resulting from higher orbital velocities (Dumas and Arnott 2006). The deposits of this unit correspond to the bottom of an inlet affected by tidal channels and storms (vortex ripples.…”

Section: Discussionmentioning

confidence: 99%

Eemian estuarine record forced by glacio-isostasy (southern Iceland)—link with Greenland and deep sea records

et al. 2018

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Origin of hummocky and swaley cross-stratification— The controlling influence of unidirectional current strength and aggradation rate

Cited by 418 publications

References 21 publications

Mass occurrence of benthic coccoid cyanobacteria and their role in the production of Neoarchean carbonates of South Africa

Mass occurrence of benthic coccoid cyanobacteria and their role in the production of Neoarchean carbonates of South Africa

Facies development of the Upper Triassic succession on Barentsøya, Wilhelmøya and NE Spitsbergen, Svalbard

Eemian estuarine record forced by glacio-isostasy (southern Iceland)—link with Greenland and deep sea records

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