Origin of megarhythms in flysch sequences of the Quebec Appalachians

1979 ◽  
Vol 16 (7) ◽  
pp. 1518-1523 ◽  
Author(s):  
Jean Lajoie
Keyword(s):  
Deep Sea ◽  
Source Area ◽  
Rock Composition ◽  
Middle Cambrian ◽  
Late Cambrian ◽  
External Domain ◽  
Vertical Evolution ◽  
Metamorphic Terranes ◽  
Sea Fan ◽  
Stratigraphic Evolution

The cyclic and positive sequences observed in the External Domain of the Quebec Appalachians between L'IsIet and Grosses Roches have been interpreted as facies of deep-sea fans that result from progradation. In these conglomerate-bearing sequences, the composition of the detritus changes up-section, which suggests that uplift of the source area played an important role in their vertical evolution. In early and (or) Middle Cambrian time, the source consisted of sedimentary, igneous, and metamorphic terranes. This provenance was rejuvenated in Late Cambrian – Early Ordovician time, and the Lower – Middle Cambrian shelf wa.s uplifted. The stratigraphic evolution of composition observed in these flysch sequences cannot be explained by deep-sea fan progradation.In recent years the general trend in flysch-sequence analysis has been away from tectonic and towards sedimentological interpretations. The stratigraphic evolution of flysch sequences may be due to both tectonic and sedimentary processes. Studies of rock composition, generally neglected by most workers, could be used to make the distinction.

Provenance et modèle de dépôt de la Formation de la Rivière Nicolet : flysch taconique du Domaine autochtone et du Domaine externe des Appalaches du Québec

1980 ◽  
Vol 17 (7) ◽  
pp. 855-865 ◽  
Author(s):  
Jean Beaulieu ◽  
Jean Lajoie ◽  
Claude Hubert
Keyword(s):  
Deep Sea ◽  
Source Area ◽  
Tectonic Activity ◽  
Middle Ordovician ◽  
External Domain ◽  
Vertical Evolution ◽  
Sea Fan ◽  
Internal Domain

The composition of the detrital fraction of the Nicolet River Formation suggests that the rocks of the Autochtonous and the External Domains of the Quebec Appalachians were mostly derived from the sedimentary nappes of the External Domain. The contribution from the metamorphic nappes and ophiolites of the Internal Domain was minor but it indicates that the dynamothermal metamorphism had been completed by the end of the Middle Ordovician (C. spiniferus Zone). Piling up of the nappes, each one progressively richer in feldspar, produced a source of high relief subject to subaerial erosion. The vertical evolution observed in the flysch probably results from tectonic activity at the source area rather than from deep-sea fan progradation. The stratigraphic relationships evince that the deposit accumulated in basins controlled by a series of horsts and grabens.

scholarly journals Stratigraphic revision and reconstruction of the deep-sea fan of the Voirons Flysch (Voirons Nappe, Chablais Prealps)

2021 ◽  
Vol 114 (1) ◽  
Author(s):  
Jérémy Ragusa ◽  
Lina Maria Ospina-Ostios ◽  
Pascal Kindler ◽  
Mario Sartori
Keyword(s):  
Deep Sea ◽  
Distal Part ◽  
Accretionary Prism ◽  
Proximal Part ◽  
Late Eocene ◽  
Lithostratigraphic Units ◽  
Stratigraphic Record ◽  
Sea Fan ◽  
Stratigraphic Evolution ◽  
Depositional Setting

AbstractThe Voirons Flysch (Caron in Eclogae Geologicae Helvetiae 69:297–308, 1976), is a flysch sequence aggregated into the sedimentary accretionary prism of the Chablais and Swiss Prealps. Its palaeogeographic location is still debated (South Piemont or Valais realm). We herein present a stratigraphic revision of the westernmost unit of the former Gurnigel Nappe sensu Caron (Eclogae Geologicae Helvetiae 69:297–308, 1976): the Voirons Flysch. This flysch is subdivided into three lithostratigraphic units at the formation level (the Voirons Sandstone, the Vouan Conglomerate, the Boëge Marl), with an additional unit (Bruant Sandstone) of uncertain attribution, ranging from the early Eocene to probably the late Eocene. We further propose a new model of the depositional setting of the deep-sea of the Voirons Flysch based on palaeocurrent directions, the overall geometry and sedimentary features. This model depicts an eastward deflected deep-sea fan. The stratigraphic record of the proximal part of this fan is fairly complete in the Voirons area, whereas its most distal part is only represented by one small exposure of thinly bedded sandstones in the Fenalet quarry. The stratigraphic evolution of the Voirons Flysch shows two major disruptions of the detrital sedimentation at the transition between Voirons Sandstone—Vouan Conglomerate and Vouan Conglomerate—Boëge Marl. The cause of these disturbances has to be constrained in the framework of the palaeogeographic location of the Voirons Flysch.

The ancestral Mississippi drainage archived in the late Wisconsin Mississippi deep-sea fan

Geology ◽  
2016 ◽  
Vol 44 (6) ◽  
pp. 479-482 ◽  
Author(s):  
A. Fildani ◽  
M.P. McKay ◽  
D. Stockli ◽  
J. Clark ◽  
M.L. Dykstra ◽  
...  
Keyword(s):  
Deep Sea ◽  
Sea Fan

scholarly journals Relative Abundance and Diversity of Bacterial Methanotrophs at the Oxic–Anoxic Interface of the Congo Deep-Sea Fan

2017 ◽  
Vol 8 ◽  
Author(s):  
Sandrine Bessette ◽  
Yann Moalic ◽  
Sébastien Gautey ◽  
Françoise Lesongeur ◽  
Anne Godfroy ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Deep Sea ◽  
Abundance And Diversity ◽  
Sea Fan

Two new species of Cossura (Cossuridae, Annelida) from the terminal lobes of the Congo River deep-sea fan

2017 ◽  
Vol 97 (5) ◽  
pp. 881-888
Author(s):  
Anna Zhadan
Keyword(s):  
New Species ◽  
Deep Sea ◽  
Anterior Margin ◽  
Posterior Part ◽  
Entire Body ◽  
Congo River ◽  
Two New Species ◽  
Dark Pigmentation ◽  
Sea Fan ◽  
Scanning Electron

Two new species of Cossura Webster & Benedict, 1887 were found in material collected during sampling from the terminal lobes of the Congo deep-sea fan. They were described using light and scanning electron microscopy. Cossura platypus sp. nov. has 15–17 thoracic chaetigers, a prostomium longer than it is wide, with a widely rounded anterior margin, an abruptly expanded posterior prostomial ring the same length as the peristomium, without a mid-ventral notch, a branchial filament attached to the midlength of chaetiger 3, and a pygidium with three anal cirri. Cossura platypus sp. nov. is similar to C. brunnea Fauchald, 1972 but differs in the shape of the prostomium, which is widely rounded anteriorly in C. platypus sp. nov. and is broadly triangular in C. brunnea; furthermore, C. platypus sp. nov.is uniformly pale, whereas C. brunnea has dark pigmentation. Cossura candida Hartman, 1955 differs from C. platypus sp. nov. in the conical shape of the prostomium and 24–35 thoracic chaetigers. Cossura flabelligera sp. nov. has 16–19 thoracic chaetigers, a conical prostomium, and a branchial filament arising from the posterior part of chaetiger 2; the entire body, including the chaetae, is covered by a thick mucous sheath similar to the tunic of flabelligerids. Cossura flabelligera sp. nov. resembles C. longocirrata Webster & Benedict, 1887 in the position of the branchial filament, the shape of the prostomium, and the number of thoracic chaetigers; it differs in having a thick mucous sheath. This character seems to be unique for the Cossuridae.

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