scholarly journals Role of Upper-Flow-Regime Bedforms Emplaced by Sediment Gravity Flows in the Evolution of Deltas

2019 ◽  
Vol 7 (1) ◽  
pp. 5 ◽  
Author(s):  
Svetlana Kostic ◽  
Daniele Casalbore ◽  
Francesco Chiocci ◽  
Jörg Lang ◽  
Jutta Winsemann
Keyword(s):  
Numerical Analysis ◽  
High Resolution ◽  
Flow Regime ◽  
Case Studies ◽  
Seismic Data ◽  
Lake Level ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Digital Elevation

Upper-flow-regime bedforms and their role in the evolution of marine and lacustrine deltas are not well understood. Wave-like undulations on delta foresets are by far the most commonly reported bedforms on deltas and it will take time before many of these features get identified as upper-flow-regime bedforms. This study aims at: (1) Providing a summary of our knowledge to date on deltaic bedforms emplaced by sediment gravity flows; (2) illustrating that these features are most likely transitional upper-flow-regime bedforms; and (3) using field case studies of two markedly different deltas in order to examine their role in the evolution of deltas. The study combines numerical analysis with digital elevation models, outcrop, borehole, and high-resolution seismic data. The Mazzarrà river delta in the Gulf of Patti, Italy, is selected to show that upper-flow-regime bedforms in gullies can be linked to the onset, growth, and evolution of marine deltas via processes of gully initiation, filling, and maintenance. Ice-marginal lacustrine deltas in Germany are selected as they illustrate the importance of unconfined upper-flow-regime bedforms in the onset and evolution of distinct delta morphologies under different lake-level trends.

Role of high quality seismic data in field development and production through case studies from a giant offshore carbonate field, Abu Dhabi, UAE

2011 ◽  
Author(s):  
Akmal Sultan ◽  
Jie Zhang ◽  
H. Ewart. Edward ◽  
S. Ahmed Hage ◽  
Khaled Shahata ◽  
...  
Keyword(s):  
Case Studies ◽  
Seismic Data ◽  
Abu Dhabi ◽  
High Quality ◽  
Field Development

scholarly journals Liqsedflow: Role of Two-Phase Physics in Subaqueous Sediment Gravity Flows

2010 ◽  
Vol 50 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Shinji Sassa ◽  
Hideo Sekiguchi
Keyword(s):  
Two Phase ◽  
Sediment Gravity Flows ◽  
Gravity Flows

Assessment of the high-resolution paleoseismicity record from sediment gravity flows in Prince William Sound, Alaska

2019 ◽  
Vol 408 ◽  
pp. 110-122
Author(s):  
Joshua R. Williams ◽  
Elisabeth R. Clyne ◽  
Steven A. Kuehl ◽  
Mohammad Al Mukaimi
Keyword(s):  
High Resolution ◽  
Prince William Sound ◽  
Sediment Gravity Flows ◽  
Gravity Flows

scholarly journals Modelling ice-cliff backwasting on a debris-covered glacier in the Nepalese Himalaya

2015 ◽  
Vol 61 (229) ◽  
pp. 889-907 ◽  
Author(s):  
Jakob F. Steiner ◽  
Francesca Pellicciotti ◽  
Pascal Buri ◽  
Evan S. Miles ◽  
Walter W. Immerzeel ◽  
...  
Keyword(s):  
Energy Balance ◽  
High Resolution ◽  
Shortwave Radiation ◽  
Balance Model ◽  
Point Scale ◽  
Radiative Fluxes ◽  
Digital Elevation ◽  
Local Topography ◽  
Elevation Model

AbstractIce cliffs have been identified as a reason for higher ablation rates on debris-covered glaciers than are implied by the insulation effects of the debris. This study aims to improve our understanding of cliff backwasting, and the role of radiative fluxes in particular. An energy-balance model is forced with new data gathered in May and October 2013 on Lirung Glacier, Nepalese Himalaya. Observations show substantial variability in melt between cliffs, between locations on any cliff and between seasons. Using a high-resolution digital elevation model we calculate longwave fluxes incident to the cliff from surrounding terrain and include the effect of local shading on shortwave radiation. This is an advance over previous studies, that made simplified assumptions on cliff geometry and radiative fluxes. Measured melt rates varied between 3.25 and 8.6 cm d−1 in May and 0.18 and 1.34 cm d−1 in October. Model results reproduce the strong variability in space and time, suggesting considerable differences in radiative fluxes over one cliff. In October the model fails to reproduce stake readings, probably due to the lack of a refreezing component. Disregarding local topography can lead to overestimation of melt at the point scale by up to ∼9%.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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