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 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.

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.

Simultaneous formation of iron-rich layers at different redox boundaries in sediments of the Amazon deep-sea fan

1998 ◽  
Vol 62 (13) ◽  
pp. 2253-2264 ◽  
Author(s):  
Sabine Kasten ◽  
Tim Freudenthal ◽  
Franz X. Gingele ◽  
Horst D. Schulz
Keyword(s):  
Deep Sea ◽  
Simultaneous Formation ◽  
Sea Fan

scholarly journals Limitations of microbial hydrocarbon degradation at the Amon mud volcano (Nile deep-sea fan)

2013 ◽  
Vol 10 (5) ◽  
pp. 3269-3283 ◽  
Author(s):  
J. Felden ◽  
A. Lichtschlag ◽  
F. Wenzhöfer ◽  
D. de Beer ◽  
T. Feseker ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Deep Sea ◽  
High Energy ◽  
Mud Volcano ◽  
Spatial And Temporal Patterns ◽  
Central Dome ◽  
Disturbed Areas ◽  
Hydrocarbon Transport ◽  
Sea Fan ◽  
Hydrocarbon Degraders

Abstract. The Amon mud volcano (MV), located at 1250 m water depth on the Nile deep-sea fan, is known for its active emission of methane and non-methane hydrocarbons into the hydrosphere. Previous investigations showed a low efficiency of hydrocarbon-degrading anaerobic microbial communities inhabiting the Amon MV center in the presence of sulfate and hydrocarbons in the seeping subsurface fluids. By comparing spatial and temporal patterns of in situ biogeochemical fluxes, temperature gradients, pore water composition, and microbial activities over 3 yr, we investigated why the activity of anaerobic hydrocarbon degraders can be low despite high energy supplies. We found that the central dome of the Amon MV, as well as a lateral mud flow at its base, showed signs of recent exposure of hot subsurface muds lacking active hydrocarbon degrading communities. In these highly disturbed areas, anaerobic degradation of methane was less than 2% of the methane flux. Rather high oxygen consumption rates compared to low sulfide production suggest a faster development of more rapidly growing aerobic hydrocarbon degraders in highly disturbed areas. In contrast, the more stabilized muds surrounding the central gas and fluid conduits hosted active anaerobic hydrocarbon-degrading microbial communities. The low microbial activity in the hydrocarbon-vented areas of Amon MV is thus a consequence of kinetic limitations by heat and mud expulsion, whereas most of the outer MV area is limited by hydrocarbon transport.

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