High frequency of sediment gravity flow events in the Var submarine canyon (Mediterranean Sea)

Since 2014, the global land and sea surface temperature has scaled 0.23 °C above the decadal average (2009–2018). Reports indicate that Mediterranean Sea temperatures have been rising at faster rates than in the global ocean. Oceanographic time series of physical and biogeochemical data collected from an onboard and a multisensor mooring array in the northwestern Mediterranean Sea (Blanes submarine canyon, Balearic Sea) during 2009–2018 revealed an abrupt temperature rising since 2014, in line with regional and global warming. Since 2014, the oligotrophic conditions of the water column have intensified, with temperature increasing 0.61 °C on the surface and 0.47 °C in the whole water column in continental shelf waters. Water transparency has increased due to a decrease in turbidity anomaly of −0.1 FTU. Since 2013, inshore chlorophyll a concentration remained below the average (−0.15 mg·l−1) and silicates showed a declining trend. The mixed layer depth showed deepening in winter and remained steady in summer. The net surface heat fluxes did not show any trend linked to the local warming, probably due to the influence of incoming offshore waters produced by the interaction between the Northern Current and the submarine canyon. Present regional and global water heating pattern is increasing the stress of highly diverse coastal ecosystems at unprecedented levels, as reported by the literature. The strengthening of the oligotrophic conditions in the study area may also apply as a cautionary warning to similar coastal ecosystems around the world following the global warming trend.

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Tricase Submarine Canyon: cold-water coral habitats in the southwesternmost Adriatic Sea (Mediterranean Sea)

Seafloor Geomorphology as Benthic Habitat ◽

10.1016/b978-0-12-814960-7.00048-8 ◽

2020 ◽

pp. 793-810 ◽

Cited By ~ 2

Author(s):

Mariacristina Prampolini ◽

Lorenzo Angeletti ◽

Valentina Grande ◽

Marco Taviani ◽

Federica Foglini

Keyword(s):

Mediterranean Sea ◽

Adriatic Sea ◽

Cold Water ◽

Submarine Canyon ◽

Water Coral

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Sediment Gravity Flow on Relatively Gentle Slopes

PROCEEDINGS OF THE JAPANESE CONFERENCE ON HYDRAULICS ◽

10.2208/prohe1975.30.235 ◽

1986 ◽

Vol 30 ◽

pp. 235-240

Keyword(s):

Gravity Flow ◽

Sediment Gravity Flow

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Recognizing tide- and wave-dominated compound deltaic clinothems in the rock record

Geology ◽

10.1130/g47767.1 ◽

2020 ◽

Vol 48 (12) ◽

pp. 1149-1153

Author(s):

Yang Peng ◽

Cornel Olariu ◽

Ronald J. Steel

Keyword(s):

Seismic Data ◽

Three Dimensional ◽

Gravity Flow ◽

Small Scale ◽

Sedimentary Record ◽

Sediment Gravity Flow ◽

Rock Record ◽

Storm Wave ◽

Tidal Deposits

Abstract Many modern deltas exhibit a compound geometry that consists of a shoreline clinoform and a larger subaqueous clinoform connected through a subaqueous platform. Despite the ubiquity of compound clinoforms in modern deltas, very few examples have been documented from the ancient sedimentary record. We present recognition criteria for shelf compound-clinoform systems in both tide- and wave-dominated deltas by integration of ancient and modern examples from multiple types of data. The compound clinothem can be identified by using a combination of: (1) the three-dimensional (3-D) configuration identified in bathymetric or seismic data, (2) bipartite stacked regressive units, consisting of a lower muddy coarsening-to-fining-upward (CUFU) or coarsening-upward (CU) unit (30–100 m thick) and an overlying sandier CU unit (5–30 m thick) (together they represent the subaqueous and shoreline clinoform pair), and (3) distinct facies described herein, though both types of delta have highly bioturbated mudstone and siltstone bottomsets. Tide-dominated deltas have muddy foresets with tidal scours containing tidal rhythmites or inclined heterolithic strata in the subaqueous clinothem overlain by river and tidal deposits of the shoreline clinothem. Wave-dominated deltas show mainly wave-enhanced sediment-gravity-flow (WSGF) beds and some thin hummocky/swaley cross-stratified (HCS/SCS) sandstones toward the top in the subaqueous muddy foreset, and upward-thickening HCS/SCS and trough/planar cross-bedded sandstones interbedded with siltstones in the shoreline clinothem. The subaqueous platform, which links the clinoform couplet, shows evidence of frequent tidal or wave reworking and redeposition. The platform in tide-dominated deltas is characterized by tide-generated heterolithic strata (e.g., bidirectional current-rippled and cross-stratified sandstones, spring and neap tidal bundles, tidal rhythmites) with occasional storm-wave–influenced strata. In contrast, the wave-dominated platform comprises small-scale swales with scours and mud clasts and some WSGF deposits. The proposed criteria can aid in the recognition of compound deltaic clinothems in other basins, particularly those with limited amounts and/or types of data.

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