Formation and preservation of an overstepped segmented lagoon complex on a high-energy continental shelf

Sedimentology ◽  
2013 ◽  
Vol 60 (7) ◽  
pp. 1755-1768 ◽  
Author(s):  
Andrew N. Green ◽  
J. Andrew G. Cooper ◽  
Rio Leuci ◽  
Zane Thackeray
Keyword(s):  
Continental Shelf ◽  
High Energy

The conundrum of biont-free substrates on a high-energy continental shelf: Burial and scour on Nantucket Shoals, Great South Channel

2020 ◽  
pp. 107089
Author(s):  
Eric N. Powell ◽  
Roger L. Mann ◽  
M. Chase Long ◽  
Jeremy R. Timbs ◽  
Kelsey M. Kuykendall
Keyword(s):  
Continental Shelf ◽  
High Energy

scholarly journals SEDIMENT TRANSPORT ON THE SOUTH-EAST AUSTRALIAN CONTINENTAL SHELF

1984 ◽  
Vol 1 (19) ◽  
pp. 131 ◽  
Author(s):  
Angus D. Gordon ◽  
John G. Hoffman
Keyword(s):  
Sediment Transport ◽  
Continental Shelf ◽  
Suspended Sediment ◽  
Transport System ◽  
Sediment Concentration ◽  
High Energy ◽  
Sediment Distribution ◽  
Sediment Movement ◽  
Shelf Sediment ◽  
Sea Bed

Engineering projects on the continental shelf off Sydney, Australia, have stimulated investigation into the sediment transport system of the shelf. Investigation activities associated with these projects have included: definition of sea bed morphology, sediment distribution and bedform characteristics; monitoring of steady and wave induced currents; wind data collection; suspended sediment sampling; bottom camera sediment movement investigations and analytical studies of sediment reaction to sea bed forcing functions. Sea bed velocity exceedence relationships for both wave oscillations and steady currents have been determined at depths of 24 m, 60 m and 80 m. Thresholds of sediment movement have been defined. Relative sediment transport computations have been undertaken and studies of suspended sediment concentration profiles are in progress so that absolute transport rates can be determined. The prevailing conditions, which include a mainly south bound current, are seldom sufficient to induce entrainment of shelf sediments. Transport events mainly result from major storms in the Tasman Sea which produce both high energy waves and north bound currents. Although these events are rare and short lived, the combined wave and current shear produced at the sea bed during the events gives rise to entrainment conditions which result in their dominance of the shelf sediment transport system.

scholarly journals Recent Foraminifera from the North Sea (Forties and Ekofisk areas) and the continental shelf west of Scotland

1985 ◽  
Vol 4 (2) ◽  
pp. 117-125 ◽  
Author(s):  
John W. Murray
Keyword(s):  
Continental Shelf ◽  
North Sea ◽  
Standing Crop ◽  
High Energy ◽  
The West ◽  
The North ◽  
Energy Environment ◽  
Bottom Waters ◽  
The North Sea ◽  
Northern North Sea

Abstract. The regions studied are all of mid continental shelf depth (70–145 m) and have bottom waters of normal marine salinity. The North Sea has lower bottom water temperatures than those to the west of Scotland. However, the major difference between the two regions is one of tidal and/or wave energy: the northern North Sea is a low energy environment of muddy sand deposition whereas the sampled part of the continental shelf west and north of Scotland is a moderate to high energy environment of medium to coarse biogenic carbonate sedimentation.The physical differences between the two main areas are reflected in the living and dead foraminiferal assemblages. The northern North Sea is a region of free-living species whereas the continental shelf west of Scotland has immobile and mobile attached species living on firm substrates. The northern North Sea is very fertile and has high standing crop values.The dead assemblages are small in size and very abundant. To the west of Scotland the sea is less fertile, standing crop values are low, the dead assemblages are moderate to large in size and reasonably abundant due to the slow rate of dilution by sediment.

scholarly journals Late Quaternary Geology of the Canterbury Continental Terrace

2021 ◽  
Author(s):  
◽  
Richard Howard Herzer
Keyword(s):  
Grain Size ◽  
Continental Shelf ◽  
Sea Level ◽  
Late Quaternary ◽  
High Energy ◽  
The South ◽  
Submarine Canyons ◽  
Radiocarbon Dates ◽  
Sea Bed ◽  
Quaternary Stratigraphy

<p>The Late Quaternary stratigraphy and sedimentary processes are interpreted for an area of continental shelf and slope on the eastern side of the South Island, New Zealand, between latitudes 43°00's and 44°50's. Two formations are recognised in the Late Quaternary stratigraphy of the shelf: the Canterbury Bight Formation of mainly Last Glacia1 age and, locally overlying it, the Pegasus Formation of mainly Holocene age. The formations are distinguished by shelf-wide unconformities (visib1e in seismic profiles), by geomorphology, by grain-size modes, and by macrofauna. Ridge-and-swa1e topography occurs on two scales on the shelf. Very large ridges and troughs are interpreted from microbathymetry, stratigraphy, sediments and macrofauna to be the remains of Pleistocene barrier/lagoon complexes. With the aid of radiocarbon dates, four well developed shorelines between 28,000 yr and 15,000 yr old are recognised. The smaller ridges are submarine features, formed by strong currents. Those ridges that are in a zone of constricted and accelerated currents near Banks Peninsula are active, while those well removed from the peninsula constriction are fossil and date from times of lower sea level. Sedimentation on the continental shelf has reached a state of equilibrium with the modern hydraulic regime. Relict sediments of the deglacial transgressive sand/gravel sheet are being reworked in zones of high energy, principally in the region of constricted flow around Banks Peninsula. Modern-input sand (distinguished by its grain-size mode) is restricted by currents mainly to an active belt near shore, but locally it has replaced palimpsest sand on the middle shelf. The modern mud facies, being confined by zones of higher energy, has reached its maximum areal extent; its greatest thickness is in Pegasus Bay. Sea-bed drifter studies, and studies of sediment texture and provenance show that net sediment movement on the shelf and along shore during both Pleistocene and modern times has been northwards. The continental slope is dissected by submarine slide scars in the south and by submarine canyons in the north. Streams of fine sand, transported from the continental shelf to the upper slope by north-flowing currents during Pleistocene lowered sea levels, initiated the erosion of submarine canyons. Interception of littoral-drifted gravel by established canyons reaching Pleistocene strand lines probably accelerated. canyon erosion. The canyons are thought to be now effectively dormant. Deposition of fine sediment from suspension has dominated the development of the southern slope. This slope is consequently free of deeply corrasional features like submarine canyons but is prone to failure by gravity sliding. The youngest slides are less than 18,000 yr old. The history of growth of Pegasus Submarine Canyon is investigated in detail. The course of the canyon across the shelf is not fault controlled. As well as growing landwards, the canyon and its tributaries have, during Pleistocene sea level stillstands, grown southwards along shore towards the supply of littoral drifted gravel and sand. A buried tributary, of Penultimate Glacial age or older, on the canyon's west side, once brought the canyon 7 km closer to the present shore. The relative ages of the south-trending arms of the canyon are inferred from their relationship to known Last Glacial shorelines that are preserved on the shelf, and by their position with respect to a regional subsurface unconformity of Penultimate Glacial age. Canyon erosion was concentrated in the largest arm during the last deglacial rise of sea level, and shallow channels, interpreted as feeders are common around its rim.</p>

Development of a continental shelf acoustic telemetry array to support behavioral research of fish in a high energy ocean environment

2022 ◽  
Vol 247 ◽  
pp. 106177
Author(s):  
Jennifer L. Cudney ◽  
Charles W. Bangley ◽  
Andrea Dell’Apa ◽  
Eric Diaddorio ◽  
Roger A. Rulifson
Keyword(s):  
Continental Shelf ◽  
Acoustic Telemetry ◽  
High Energy ◽  
Behavioral Research ◽  
Ocean Environment
Sign in / Sign up

Export Citation Format

Share Document