Origin, structure and evolution of submarine canyons on central and southern continental slopes of Okinawa Trough and its potential genetic mechanism related to methane seepage

2021 ◽  
Author(s):  
Deyong Li ◽  
Jie Liang ◽  
Honggang Cheng ◽  
Gang Dong ◽  
Xiting Liu ◽  
...  
Keyword(s):  
Okinawa Trough ◽  
Genetic Mechanism ◽  
Submarine Canyons ◽  
Methane Seepage ◽  
Continental Slopes

Controls on the evolution of submarine canyons in steep continental slopes: geomorphological insights from Palar Basin, southeastern margin of India

2021 ◽  
Vol 41 (1) ◽  
Author(s):  
S. Susanth ◽  
P. John Kurian ◽  
C. M. Bijesh ◽  
D. Twinkle ◽  
Abhishek Tyagi ◽  
...  
Keyword(s):  
Submarine Canyons ◽  
Continental Slopes ◽  
Southeastern Margin ◽  
Palar Basin

A Suggested Origin of Continental Slopes and of Submarine Canyons

1950 ◽  
Vol 87 (2) ◽  
pp. 102-104 ◽  
Author(s):  
K. O. Emery
Keyword(s):  
Sea Level ◽  
Shear Plane ◽  
Continental Margins ◽  
Submarine Canyons ◽  
Continental Shelves ◽  
Continental Slopes

AbstractThrusting along a shear plane at the continental margins may result in a temporary up-bulging of the margins above sea-level. During the time of exposure erosion by streams should have incised canyons which now, after isostatic readjustment of the margins, constitute the widely distributed submarine canyons. Known downwarped peneplains below the surface of continental shelves may have been developed on the bulged margins by long continued erosion. The margins may, thus, have served as- sources of some sediments now found on land and believed to have been derived from a seaward direction.

The history of the Nahariya Submarine Canyon, offshore northern Israel, from sedimentary down core records and foraminiferal analyses

2021 ◽  
Author(s):  
Naomi Moshe ◽  
Oded Katz ◽  
Adi Torfstein ◽  
Mor Kanari ◽  
Pere Masque ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Eastern Mediterranean ◽  
Transport Processes ◽  
Mass Wasting ◽  
Submarine Canyons ◽  
Last Glacial ◽  
Erosion Processes ◽  
Foraminiferal Species ◽  
Continental Slopes ◽  
The Last Glacial

<p>Submarine canyons are prominent features in continental slopes. They play an important role in sediment transport to the deep sea, as they form conduits for turbidity currents and cause landslides due their steep slopes. Such mass transport events could create geo-hazards, which compromise infrastructures along the continental slope.</p><p>Our research focuses on the Nahariya Canyon, which is part of a series of submarine canyons located along the continental slopes of the eastern Mediterranean, offshore northern Israel. This canyon is incised into the slope and does not reach the shelf. Here, we report the results from a study of two piston cores sampled in the canyon at water depths of 650m (NAC650, ~2.5m long) and 915m (NAC915, ~6m long). Chronologies were established based radiocarbon dating using slope foraminiferal shells, in addition to <sup>210</sup>Pb and OSL dating of bulk sediment. The sediments were characterized by major and trace element concentrations, mineralogy, grain size, and dead foraminiferal assemblages. We further identified the living (Rose-Bengal stained) foraminiferal species at three depths habitats (200m 650m and 915m water depth).</p><p>Our results show that both piston cores are comprised of a capping ~40 cm thick interval of fine laminated mud, deposited over the last ~150-200 years, apparently reflecting hemipelagic sedimentation. This capping interval unconformably overlays a consolidated sequence in both cores, which indicates a major sediment removal. The consolidated sequence in NAC650 is mostly homogenous and dates to the previous glacial (>140 ka), and in NAC915 the upper 70 cm of the consolidated sequence consists mud clasts dated to 27-46 ka that overlay an ‘S shape’ shear zone, which is a result of a down canyon mass wasting (debrite). Below that debrite, the sediment is mostly homogenous and dates to the last glacial (>25 ka). Broken shells of shallow benthic foraminiferal species such as Ammonia spp., Asterigerinata mamilla, Miliolids, Rosalina spp. and Sorites orbiculus are found abundantly throughout both piston-cores, varying between in-core intervals, indicating that allochthonous sediments are prevalent at those cores. Same shallow species are found also in the surface (living) assemblages, mixed with slope deep foraminiferal species. Moreover, the deep living foraminiferal shells are well preserved, in contrast to the shallow living species. Taken together, these indicate that sediment transport processes along the canyon exist to this day.</p><p>The cores suggest that the canyon is an erosive environment at least since the last glacial maximum, when the last significant mass wasting deposit is recorded. The Holocene is not represented in the records, probably due to the dominance of erosion processes, except for a thin layer of sediment deposited over the last two centuries that prevails along the entire canyon.</p>

Density Currents in connection with the problem of Submarine Canyons

1938 ◽  
Vol 75 (6) ◽  
pp. 241-249 ◽  
Author(s):  
Ph. H. Kuenen
Keyword(s):  
United States ◽  
East Coast ◽  
The United States ◽  
Geodetic Survey ◽  
Density Currents ◽  
Submarine Canyons ◽  
Comprehensive View ◽  
Continental Slopes ◽  
The Many

The investigation of submarine canyons has been actively pursued in the United States of latter years, principally due to the activities of F. P. Shepard. The Coast and Geodetic Survey has mapped a large number of these interesting chasms, both along the Atlantic and Pacific continental slopes, by sonic soundings; Shepard himself added data by soundings and dredgings along the Californian coast; Stetson performed current measurements, dredgings, and sampling in the canyons off the east coast. The number of data is steadily increasing in the United States, and it is to be hoped other nations will also become active, for much still remains to be learned before a comprehensive view of the many-sided problem can be obtained.

Three dimensional underwater acoustic modeling on continental slopes and submarine canyons

2014 ◽  
Vol 136 (4) ◽  
pp. 2317-2317
Author(s):  
Ying-Tsong Lin ◽  
David Barclay ◽  
Timothy F. Duda ◽  
Weifeng Gordon Zhang
Keyword(s):  
Three Dimensional ◽  
Acoustic Modeling ◽  
Submarine Canyons ◽  
Underwater Acoustic ◽  
Continental Slopes

scholarly journals Comparison between Recent benthic foraminiferal faunas of the Porcupine Seabight and Western Approaches Continental Slope

1985 ◽  
Vol 4 (2) ◽  
pp. 165-183 ◽  
Author(s):  
Janice F. Weston
Keyword(s):  
Continental Slope ◽  
Bottom Water ◽  
Sediment Type ◽  
The South ◽  
Submarine Canyons ◽  
Porcupine Seabight ◽  
Water Characteristics ◽  
Continental Slopes ◽  
Well Depth

Abstract. Although only 1 degree of latitude apart, the South Western Approaches and Porcupine Seabight continental slopes support widely differing benthic foraminiferal faunas. The less energetic, less variable, muddier conditions of the prograding margin of the Porcupine Seabight yield foraminiferal faunas which show extremely good zonations with respect to depth and are dominated by species such as Trifarina angulosa, Gavelinopsis lobatulus and Uvigerina pygmaea. The more variable and more energetic conditions of the submarine canyons of the Western Approaches margin do not support well depth zones faunas, but assemblages which are generally dominated by more cosmopolitan and robust species, such as Cassidulina carinata, Brizalina dilatata and B.subaenariensis. Such differences may be related to factors such as a greater variability of sediment type and bottom water characteristics and a more energetic environment in the Western Approaches area.

scholarly journals Review of Methane Seepages in the Okinawa Trough: Progress and Outlook

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Ang Li ◽  
Qing Li ◽  
Cuiling Xu ◽  
Feng Cai ◽  
Hongbin Wang
Keyword(s):  
Okinawa Trough ◽  
Genomic Analysis ◽  
Future Research ◽  
Cold Seeps ◽  
Biogeochemical Processes ◽  
Methane Seeps ◽  
Methane Seepage ◽  
Geological Processes ◽  
The Okinawa Trough ◽  
Material Cycling

It has been two decades since the cold seeps were firstly found in the Okinawa Trough (OT). The scientific cruises and the geological surveys since then have unveiled the currently active submarine methane seeps and significantly improved the understanding of methane seeps in the back-arc basin of the OT. In this paper, we review the up-to-date progress of the research of methane seepages then put forward the promising, yet challenging, outlook by listing the unsolved questions of the cold seeps in the OT. Multiple approaches and techniques, including seismic and echo-sounder recording, dredging, gravity-piston and ROV coring, seafloor drilling, and isotopic and microarray-based genomic analysis, have been used to reveal the geological processes responsible for the seeping activities and the biogeochemical processes related to them. The geophysical signature associated with gas seeps mainly includes the acoustic turbidity in the subsurface, the anomaly of the backscattering intensity at the seabed, and the gas plumes observed in the water column. Pore water and methane-derived authigenic carbonate archive the intensification of methane seepage and the paleoenvironment changes at different time scales. The methane feeding of the seeps in the OT was generated mostly via the microbially mediated process and has an origin mixed by thermogenic hydrocarbon gas in the middle OT. Sulfate-driven and Fe-driven anaerobic oxidations of methane are suggested to be the key biogeochemical processes, which would shape the material cycling in the seeping environment. The future research on the cold seeps in the OT is worth looking forward to due to its geographic and potential geologic links with the nearby hydrothermal activities. Multidisciplinary studies are expected to concentrate on their link with the undiscovered gas hydrates, the amount of methane transferring into the oceans and its impact on the climatic change, and the evolution of the seeping activities accompanied by the biogeochemical processes.

Methane seepage inferred from pore water geochemistry in shallow sediments in the western slope of the Mid-Okinawa Trough

2018 ◽  
Vol 98 ◽  
pp. 306-315 ◽  
Author(s):  
Cuiling Xu ◽  
Nengyou Wu ◽  
Zhilei Sun ◽  
Xianrong Zhang ◽  
Wei Geng ◽  
...  
Keyword(s):  
Pore Water ◽  
Okinawa Trough ◽  
Western Slope ◽  
Water Geochemistry ◽  
Methane Seepage ◽  
Pore Water Geochemistry ◽  
Shallow Sediments
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