Topic
Wave base
About: Wave base is a research topic. Over the lifetime, 219 publications have been published within this topic receiving 6900 citations.
Papers published on a yearly basis
1 / 2
Papers
TL;DR: Hummocky cross-stratification is an important structure formed on the shoreface and shelf by waves as mentioned in this paper, and it characterizes a wave-dominated facies.
Abstract: Hummocky cross-stratification is an important structure formed on the shoreface and shelf by waves. It characterizes a wave-dominated facies. Attention to its variability can reveal much about sedimentary history and paleogeography. Diagnostic traits are antiformal hummocks and synformal swales defined by randomly oriented, even lamination with dip angles and truncation angles of < 15°. Hummocky stratification forms primarily in silt to fine sand. Although size grading of individual laminae is not characteristic, concentrations of mica and plant detritus in the tops of many laminae indicate a shape sorting. Parting lineation is common. Hummocky beds vary in thickness from a few centimetres to 5 or 6 m; bed sets may be tens of metres thick. Hummocky stratification apparently is formed most commonly by redeposition below normal fair-weather wave base of fine sand delivered offshore by flooding rivers and scour of the shoreface or shoals by large waves. Deposition involves both fallout from suspension and lateral tractive flow due to wave oscillation. There is evidence that, under intense oscillatory flow, large waves drape sand over an irregular scoured surface and also mold sand into roughly circular, unoriented hummocks and swales. We postulate that these circumstances are analogous to the transition to upper flat-bed conditions in unidirectional flow.
Hummocky stratification shows important variability. It occurs in both regressive (progradational) and transgressive strata in intervals a few centimetres to 175 m thick and may be interstratified with mudstone, sandstone, or conglomerate. Hummocky stratification commonly occurs in repetitive successions with the products of individual depositional events being clearest where mudstone separates hummocky beds. An idealized hummocky stratification sequence , which can serve a purpose similar to the Bouma sequence for graded beds, is as follows (bottom to top): first-order scoured base (± sole marks); characteristic hummocky zone with several second-order truncation surfaces separating individual undulating lamina sets; a zone of flat laminae ; a zone with well-oriented ripple cross-laminae and symmetrical ripple forms; all overlain by a more or less burrowed mud-stone or siltstone . This sequence reflects waning of storm waves followed by fair-weather sedimentation and burrowing. Variations from this idealized conceptual sequence involve omissions and/or expansions of one or more of the zones. The most common variant is amalgamation either by the stacking of successive hummocky zones or by intense bioturbation that obliterates original boundaries between depositional units. Other variations include units commencing with flat-lamination; units with predominant cross-lamination; and lenticular micro-hummocky lenses within shale. Combinations of relative sand supply, relative depth, tidal range, frequency, duration and magnitude of storms, and relative productivity for a burrowing benthos must account for such differences. Further documentation of variations in hummocky stratification should reveal important details about these factors.
967 citations
TL;DR: A refined scheme of reefal limestone classification, which places more emphasis on the > 2 mm components (conglomeratic fraction) and on the mode of organic binding, allows for a more detailed facies description of organic buildups as mentioned in this paper.
Abstract: A refined scheme of reefal limestone classification, which places more emphasis on the > 2 mm components (conglomeratic fraction) and on the mode of organic binding, allows for a more detailed facies description of organic buildups. The classification has been applied to Late Devonian organic buildups which outcrop on northeastern Banks Island, Canadian Arctic Archipelago. The distribution and sequences of facies in one organic buildup has led to the determination of absolute water depth limits of three major Late Devonian paleoecological zones. Corals were the dominant fauna below 70 feet (21 m.); tabular stromatoporoids flourished between 70 feet (21 m.) and 30 feet (9 m.) of water depth; massive stromatoporoids were the dominant fauna between 30 feet (9 m.) and sea level. The main controlling factor on the depth limits of the zones was wave energy (normal wave base, 30 feet [9 m.]; storm wave base, 70 feet [21 m.]).
343 citations
TL;DR: Cambrian carbonate strata of the Great Basin deposited below fairweather wave base but above mean storm wave base (inner shelf), and below mean storm-wave base, but above maximum stormwave base (middle shelf) were examined for extent and depth of bioturbation as mentioned in this paper.
Abstract: Cambrian carbonate strata of the Great Basin deposited below fairweather wave base but above mean storm wave base (inner shelf), and below mean storm wave base but above maximum storm wave base (middle shelf) were examined for extent and depth of bioturbation. Data indicate that initial extensive colonization of marine infaunal habitats occurred between Tommotian and Atdabanian time. Throughout the remaining 65 m.y. of Cambrian time bioturbation increased, although depth of bioturbation remained relatively constant at less than 6 cm. During this time, the amount of bioturbation in the inner shelf was greater than that in the middle shelf.
194 citations
TL;DR: In this article, the superelevation of mean water level owing to the presence of breaking incident waves, measured at the shoreline of a natural beach, was found to be about 0.17Hs,∞, where Hs∞ is the significant wave height in deep water.
Abstract: Wave set-up, the superelevation of mean water level owing to the presence of breaking incident waves, was measured at the shoreline of a natural beach. Offshore pressure sensors monitored incident wave conditions. The set-up of the shoreline was found to be about 0.17Hs,∞, where Hs∞ is the significant wave height in deep water.
178 citations
TL;DR: In this article, the erosional component of the basal discontinuity of the Viking Formation is defined as a boundary that was transgressively modified during subsequent relative sea-level rise, and is commonly demarcated by Glossifungites ichnofacies.
Abstract: The Viking Formation of the Joffre field comprises parts of three discrete sequences. Sequence 2 overlies an erosional discontinuity, termed BD-1, which is incised into underlying marine parasequences of the informally named "Regional Viking". The surface represents a sequence boundary that was transgressively modified during subsequent relative sea-level rise, and is commonly demarcated by the Glossifungites ichnofacies. Up to three parasequences are truncated by BD-1. Sequence 2 comprises an incised sandstone body passing basinwards into a granule- to pebble-bearing sandy mudstone. A complete facies succession consists of a thin granule to pebble lag mantling BD-1, grading upwards into thoroughly bioturbated gritty sandy mudstone, through intensely burrowed muddy sandstone, and into interbedded hummocky cross-stratified sandstone and burrowed sandstone. The facies contain diverse and uniformly distributed, open-marine trace-fossil suites displaying an upward progression from archetypal Cruziana through proximal Cruziana and into mixed Skolithos-Cruziana assemblages. The succession is interpreted to reflect a weakly storm-influenced upper offshore to proximal lower-shoreface deposit. Incised shorefaces are allocyclically generated, and may be produced by forced regressive (falling stage), lowstand, or transgressive scenarios. Sequence 2 of the Joffre area is interpreted as a transgressively incised shoreface. It is distinguished from the other two sharp-based shoreface types largely on the basis of the extent of the erosional component of its basal discontinuity. In distal positions, BD-1 remains erosional even where it is overlain by facies deposited below fair-weather wave base. This is inconsistent with forced regressive and lowstand conditions because in weakly storm-influenced shorefaces, the regressive surface of erosion and the sequence boundary, respectively, pass into correlative conformities seaward of fair-weather wave base. Facies deposited below fair-weather wave base would therefore overlie the non-erosional correlative conformity surface. In a transgressive scenario, however, ravinement during erosional shoreface retreat generates an erosional discontinuity that may lie seaward of fair-weather wave base during subsequent progradation, because the surface was cut prior to progradation and while sea level was considerably lower. As a result, facies deposited below fair-weather wave base can overlie the erosional discontinuity.
161 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 5 |
| 2020 | 3 |
| 2019 | 3 |
| 2018 | 3 |
| 2017 | 3 |
| 2016 | 9 |