Intertidal flat sediments and their environments of deposition in the Wash

Evans, Graham

doi:10.1144/gsjgs.121.1.0209

Cited by 264 publications

(108 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Symmetrical wave ripples such as those appearing in Unit 6 are found on higher tidal flats (EVANS, 1965), thus marking the end of the depositional phase in the tidal environment.…”

Section: Auréoles D'oxyde De Fer Unité 4 (éChelle = 25 Cm)mentioning

confidence: 99%

Marine Regression and Palaeoenvironments During the Holocene in the Richardson River Basin, District of Mackenzie, N.W.T.

Kerr¹

2007

gpq

View full text Add to dashboard Cite

A detailed stratigraphie analysis was carried out on a river-bank section of late Quaternary marine sediments in the Richardson River Basin, N.W.T. The sedimentary sequence represents a gradual shallowing of the sea in an estuarine environment, from a relatively shallow marine faciès to an intertidal environment. The withdrawal of the sea from the Richardson River Basin began prior to 10,300 years BP. Isostatic uplift caused the gradual regression of the sea to its present-day level. The marine sediments yielded 26 ostracode and 14 foraminifer species. Faunal evidence is indicative of brackish-water marginal marine conditions resulting from the dilution of nearshore marine waters by freshwater discharge from the many streams and rivers draining the basin of the Richardson River.Nous avons effectué une étude détaillée d'une coupe stratigraphique de dépôts marins dans le bassin de la rivière Richardson, T.-N.-O. La séquence sédimentaire étudiée représente une régression marine dans un milieu estuarien. Elle débute par un faciès marin mis en place en eau peu profonde et évolue vers un faciès intertidal. Le retrait de la mer dans ce bassin a commencé avant 10 300 ans BP. Le relèvement isostatique terrestre est responsable de la régression marine graduelle jusqu'à son niveau actuel. Les sédiments marins contiennent 26 espèces d'ostracodes et 14 espèces de foraminifères; cette microfaune témoigne de conditions marines marginales d'eaux saumâtres résultant de la dilution de l'eau marine littorale par un apport d'eau douce des rivières drainant le bassin de la rivière Richardson

show abstract

“…Symmetrical wave ripples such as those appearing in Unit 6 are found on higher tidal flats (EVANS, 1965), thus marking the end of the depositional phase in the tidal environment.…”

Section: Auréoles D'oxyde De Fer Unité 4 (éChelle = 25 Cm)mentioning

confidence: 99%

Marine Regression and Palaeoenvironments During the Holocene in the Richardson River Basin, District of Mackenzie, N.W.T.

Kerr¹

2007

gpq

View full text Add to dashboard Cite

show abstract

“…D'après la plupart des auteurs (Chapman, 1960(Chapman, , 1977Evans, 1965 ;Reineck, 1972Reineck, , 1978Frey et Basan, 1978 ;Reineck et Singh, 1980 ;Allen et Pye, 1992), le marais intertidal (tidal marsh) correspond à la zone couverte de végétation sujette aux inondations périodiques de la marée. Il s'agit d'un tapis végétal continu et relativement dense, bien que parfois caractérisé par des mares, des chenaux de marée ou des espaces dénudés (Verger, 1968 ;Dionne, 1972 ;Paskoff, 1998).…”

Section: Terminologieunclassified

Âge et taux moyen d’accrétion verticale des schorres du Saint-Laurent estuarien, en particulier ceux de Montmagny et de Sainte-Anne-de-Beaupré, Québec

Dionne

2006

gpq

View full text Add to dashboard Cite

D’un point de vue géologique, les marais intertidaux (schorres supérieurs) constituent une formation sédimentaire originale. Ceux du Saint-Laurent estuarien sont constitués de trois faciès superposés généralement mis en place au-dessus d’un substrat limono-argileux (dépôt pélitique de la Mer de Goldthwait) taillé en surface d’érosion. Selon le secteur, le dépôt à la base du schorre supérieur possède les caractéristiques des slikkes vaseuses ou sableuses, ou bien des bas estrans sableux et graveleux. La deuxième unité (la plus importante en épaisseur), constituée de vase (limon sableux) et de débris de plantes en place, correspond à un faciès de schorre inférieur. Plus organique, la troisième unité, en surface, est caractéristique d’un faciès de schorre supérieur. Les schorres du Saint-Laurent estuarien sont des formations sédimentaires relativement récentes. Si le substrat limono-argileux date du début de l’Holocène (12,5-10 ka), la mise en place des trois unités constituant le schorre supérieur a eu lieu seulement au cours du dernier millénaire. Dans les deux principaux sites étudiés (Montmagny et Sainte-Anne-de-Beaupré), l’unité 1 a été mise en place entre 400 et 900 BP environ, l’unité 2, entre 130 et 400 BP, alors que l’unité 3, en général encore en accrétion verticale, a, pour l’essentiel, été édifiée au cours du dernier siècle. Bien que le taux moyen d’accrétion verticale à long terme varie d’un site à l’autre, il est à peu près partout légèrement inférieur à celui de la plupart des schorres dans le monde pour la même période. Dans 68,5 % des cas, il se situe entre 1 et 2 mm/an, dans 21 % des cas, entre 2 et 3 mm/an, et dans 10,5 % des cas, au-dessus de 3 mm/an. Menacés à la fois par l’érosion et les empiétements, les schorres du Saint-Laurent estuarien, en raison de leur faible superficie ainsi que de leur valeur écologique et économique, méritent d’être mieux connus, protégés et mis en valeur.From a geological point of view, intertidal marshes (high marshes) are an original sedimentary formation. Those in the St. Lawrence estuary are made of three superposed facies generally overlying a silty-clayey substrate (a pelitic deposit of the postglacial Goldthwait Sea), cut into an erosion surface. Depending on the area, the basal deposit of high marshes has the characteristics of a mud tidal flat or a lower sandy and gravelly strand. The second unit (the most important in thickness), made of laminated mud (sandy silt) and remains of plants in growing position, is a low marsh facies deposit. More organic, the third unit, at the surface, is a high marsh facies deposit. The St. Lawrence intertidal marshes are relatively recent sedimentary deposits. Although the clay substrate is an early Holocene deposit (12.5-10 ka), the three units of the high marsh were emplaced only during the last millennium. In the two main marshes studied (Montmagny and Sainte-Anne-de-Beaupré), unit 1 was formed between 400 and 900 BP, unit 2, between 130 and 400 BP and unit 3, which is generally still in vertical accretion process, was mai...

show abstract

“…These units are interpreted to be peritidal (supratidal, inter tidal, and subtidal) deposits (Friedman and Sanders, 1979;Evans, 1965;Ruitenberg and McCutcheon, 1978;Pickerell and Pajari, 1976;Elliott, 1978) based on the occurrence of shallow marine fossils, sedimentary structures, fine grain size and lack of re working by waves. The sandstone deposits could be beach or bar deposits.…”

Section: Sedimentary Unitsmentioning

confidence: 99%

Early Devonian bimodal volcanic rocks of Southwestern New Brunswick: petrography, stratigraphy, and depositional setting

Wagner

McNeil

Fay

1988

atgeol

View full text Add to dashboard Cite

The coastal volcanic belt of the northeastern United States and New Brunswick consists of a bimodal sequence of marine to subaerial Silurian and Early Devonian volcanic and associated sedimentary rocks. The Mascarene lithostratigraphic terrane of New Brunswick is probably the northern extension of this belt. This paper describes the volcanic stratigraphy, eruptive and depositional styles, paleogeography and tectonic setting of a 125 km2 area of the Mascarene terrane located along the coast of Passamaquoddy Bay. The area mapped includes a ~ 3.5 km thick bimodal and subalkaline volcanic sequence of interbedded rhyolitic and basaltic flows and pyroclastic rocks and tenigeneous shale and sandstone. These rocks were intruded by the St. George Batholith and overlain unconformably by the Late Devonian Perry Formation. The area is divided into 53 lithologic units which are mappable at a scale of 1:10,000. Rhyolitic rocks are volumetrically most important.Hawaiian, Strombolian, Plinian and Vulcanian eruptive systems are represented. The mafic units form flow, scoria cone, phreatomagmatic tuff cone, and peperitic breccia deposits. The felsic units were emplaced as welded and nonwelded air-fall, ash cloud, ground and base surge, and pyroclastic flow deposits, as well as lava flows and domes. There are three cycles of mafic/ felsic volcanism. The shale, sandstone and mudstone units in the lower part of the section are littoral deposits. The uppermost sedimentary rock unit is a fluvial deposit. The volcaniclastic units primarily contain air-fall volcanic fragments within the littoral sediments. Reworked volcanic rocks are rare. All the sedimentary units contain well-preserved cuspate and scoriaceous basaltic and rhyolitic glass shards, indicating deposition in a low-energy environment with rapid sedimentation rates. Sedimentation was concomittant with volcanism and there were no marked periods of volcanic quiescence. Facies analysis and unit morphology indicate eruptions from multiple small volcanic centres. The basaltic flows, however, consistently flowed from the north and northeast to the south suggesting eruption from a single rift system. Several depositional settings were considered, but considering constraints based on (1) composition of the volcanic rocks, (2) nature of volcanic cycles, (3) thickness of the sequence and the subsidence history, (4) rates of sedimentation, (5) facies relationships, and (6) synvolcanic structures, the most likely setting is a volcanic plateau lacking large calderas located within a continental rift.La ceinture volcanique cohere du Nouveau-Brunswick et du nord-ouest des Etats-Unis comprend une serie bimodale de volcanites marines a subaeriennes, d 'age silurien a eodevonien, et les roches sedimentaires qui leur sont associees. La Laniere lithostratigraphique de Mascarene represente probablement l'extension septentrionale de cette ceinture au Nouveau-Brunswick. Cet article decrit la stratigraphie volcanique, les styles eruptifs et de depot, la pal6ogeographie et l 'environnement tectoniqu...

show abstract

Intertidal flat sediments and their environments of deposition in the Wash

Cited by 264 publications

References 20 publications

Marine Regression and Palaeoenvironments During the Holocene in the Richardson River Basin, District of Mackenzie, N.W.T.

Marine Regression and Palaeoenvironments During the Holocene in the Richardson River Basin, District of Mackenzie, N.W.T.

Âge et taux moyen d’accrétion verticale des schorres du Saint-Laurent estuarien, en particulier ceux de Montmagny et de Sainte-Anne-de-Beaupré, Québec

Early Devonian bimodal volcanic rocks of Southwestern New Brunswick: petrography, stratigraphy, and depositional setting

Contact Info

Product

Resources

About