Characterization of recent deep-sea debrites in the Eastern Mediterranean based on foraminiferal taphonomy

2020 ◽  
Author(s):  
Oded Katz ◽  
Leeron Ashkenazi ◽  
Shani Sultan-Levi ◽  
Sigal Abramovich ◽  
Ahuva Almogi-Labin ◽  
...  
Keyword(s):  
Mass Transport ◽  
Continental Slope ◽  
Deep Sea ◽  
Eastern Mediterranean ◽  
Last Deglaciation ◽  
Noticeable Increase ◽  
The Last Deglaciation ◽  
Mass Transport Deposits ◽  
Lower Water Column

<p>It is hypothesized that submarine transport of sediments down a continental slope induce physical disintegration of pristine (non-broken) foraminifera shells, and thus mass transport deposits should include a significant percentage of fragmented shells. To validate this hypothesis, we studied two gravity-cores from the Eastern-Mediterranean continental slope, offshore Israel: AM113 sampled within a landslide lobe at 848 m water depth, and AM015 located away from a landslide at 1080 m. At least one interval, ~0.5 m thick, of massive sediments hosting mud-clasds (i.e. debrite) was identified within each core. The timing of these debrites, based on biostratigraphy, oxygen isotopes and total organic carbon data, predates sapropel S1 in both cores and is contemporaneous (AM113) or slightly predates (AM015) the most recent deglaciation.</p><p>We found a noticeable increase in benthic and planktic foraminiferal shells fragmentation through the last deglaciation and up to the base of S1. This strongly-fragmented sequence is located in the debrite of AM113 but it is overlaying the debrite of AM015. Accordingly, we suggest two possible mechanisms for the increased fragmentation of foraminiferal shells in both cores: Sediment transport and turbulence related to submarine mass-transport events, or geochemical changes in the lower water column properties at the transition from MIS-2 to the Holocene.</p>

Characterization of recent deep-sea debrites in the eastern Mediterranean based on foraminiferal taphonomy

2020 ◽  
Vol 500 (1) ◽  
pp. 377-391 ◽  
Author(s):  
Oded Katz ◽  
Leeron Ashkenazi ◽  
Shani Sultan-Levi ◽  
Sigal Abramovich ◽  
Ahuva Almogi-Labin ◽  
...  
Keyword(s):  
Mass Transport ◽  
Continental Slope ◽  
Eastern Mediterranean ◽  
Last Deglaciation ◽  
Noticeable Increase ◽  
The Last Deglaciation ◽  
Mass Transport Deposits ◽  
Heterogeneous Sediments ◽  
Lower Water Column

AbstractIt is hypothesized that submarine transport of sediments down a continental slope induces physical disintegration of pristine (non-broken) foraminiferal shells, and thus mass transport deposits should include a significant percentage of fragmented shells. To validate this hypothesis, we studied two gravity-cores from the eastern Mediterranean continental slope, offshore Israel: AM113 sampled within a landslide lobe at 848 m water depth, and AM015 located away from a landslide at 1080 m. At least one interval, c. 0.5 m thick, of heterogeneous sediments (i.e. debrite) was identified within each core. The timing of these debrites, based on biostratigraphy, oxygen isotopes and total organic carbon data, predates sapropel S1 in both cores and is contemporaneous (AM113) or slightly predates (AM015) the most recent deglaciation.We found a noticeable increase in the fragmentation of benthic and planktic foraminiferal shells through the last deglaciation and up to the base of S1. This strongly fragmented sequence is located in the debrite of AM113 but overlays the debrite of AM015. Accordingly, we suggest two possible mechanisms for the increased fragmentation of foraminiferal shells in both cores: sediment transport and turbulence related to submarine mass-transport events, or geochemical changes in the lower water column properties at the transition from MIS-2 to the Holocene.

Mass-transport deposits on the Rosetta province (NW Nile deep-sea turbidite system, Egyptian margin): Characteristics, distribution, and potential causal processes

2008 ◽  
Vol 250 (3-4) ◽  
pp. 180-198 ◽  
Author(s):  
Sébastien Garziglia ◽  
Sébastien Migeon ◽  
Emmanuelle Ducassou ◽  
Lies Loncke ◽  
Jean Mascle
Keyword(s):  
Mass Transport ◽  
Deep Sea ◽  
Causal Processes ◽  
Turbidite System ◽  
Mass Transport Deposits

scholarly journals Rapid shifts in circulation and biogeochemistry of the Southern Ocean during deglacial carbon cycle events

2020 ◽  
Vol 6 (42) ◽  
pp. eabb3807
Author(s):  
Tao Li ◽  
Laura F. Robinson ◽  
Tianyu Chen ◽  
Xingchen T. Wang ◽  
Andrea Burke ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Ocean Circulation ◽  
Deep Sea ◽  
Deep Ocean ◽  
Biological Pump ◽  
Last Deglaciation ◽  
Proxy Data ◽  
Ocean Ventilation ◽  
Carbon Release ◽  
The Last Deglaciation

The Southern Ocean plays a crucial role in regulating atmospheric CO2 on centennial to millennial time scales. However, observations of sufficient resolution to explore this have been lacking. Here, we report high-resolution, multiproxy records based on precisely dated deep-sea corals from the Southern Ocean. Paired deep (∆14C and δ11B) and surface (δ15N) proxy data point to enhanced upwelling coupled with reduced efficiency of the biological pump at 14.6 and 11.7 thousand years (ka) ago, which would have facilitated rapid carbon release to the atmosphere. Transient periods of unusually well-ventilated waters in the deep Southern Ocean occurred at 16.3 and 12.8 ka ago. Contemporaneous atmospheric carbon records indicate that these Southern Ocean ventilation events are also important in releasing respired carbon from the deep ocean to the atmosphere. Our results thus highlight two distinct modes of Southern Ocean circulation and biogeochemistry associated with centennial-scale atmospheric CO2 jumps during the last deglaciation.

Slumps Mass-Transport Deposits in the Brazilian Continental Margin Deep Water: Offshore Potiguar Basin, NE Brazil.

2020 ◽  
Author(s):  
Yoe Perez ◽  
Julia Fonseca ◽  
Helenice Vital ◽  
Andre Silva ◽  
David Castro
Keyword(s):  
Mass Transport ◽  
Continental Slope ◽  
Continental Margin ◽  
Deep Water ◽  
Negative Impact ◽  
Water Area ◽  
Passive Margin ◽  
Rift System ◽  
Potiguar Basin ◽  
Mass Transport Deposits

<p>The Brazilian Continental Margin (BEM) deep-water regions contain important geological features that need advance in their characterization. Mass-transport deposits (MTD) are important not only by their significance in the sedimentary but also because of their negative impact economically. A slump is a coherent mass of sediment that moves on a concave-up glide plane and undergoes rotational movements causing internal deformation and one of the basic types of MTD. The study area comprises part of the offshore Potiguar Basin in NE Brazil, on the distal eastern portion of the Touros High and Fernando de Noronha Ridge. This portion of the Potiguar Basin comprises a transform rift system that has evolved into a continental passive margin. This basin represents an important location related to the breakup between South America and Africa. The database used in this work included 2D post-stack time-migrated seismic profiles from the Brazilian Agency of Petroleum, Natural Gas, and Biofuels (ANP). The slumps reflectors are identified on the continental shelf profiles in form of present clinoform configuration, medium to high continuity, high amplitudes, and medium to high frequencies, representing a sigmoidal oblique complex prograding reflector. The slump scars at the continental slope indicate that this is a gravitationally unstable area that will eventually collapse, resulting in erosional features on the continental slope and deposition on the continental rise. Our results provide some insights regarding MDT slumps sedimentary evolution in the BEM deep water area as well as their interrelation with other sedimentary deposits.</p>

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