Turbidites and megaturbidites from the Herodotus abyssal plain (eastern Mediterranean) unrelated to seismic events

Cita, Maria Bianca; Beghi, C.; Camerlenghi, Angelo; Kastens, Kim A.; McCoy, Floyd W.; Nosetto, A.; Parisi, E.; Scolari, Federica; Tomadin, L.

doi:10.1016/0025-3227(84)90134-8

Cited by 72 publications

(45 citation statements)

References 12 publications

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“…Farther west, two types of Pleistocene to Holocene turbidites were recovered in piston cores from the Herodotus abyssal plain southeast of the Olimpi area (Cita et al, 1984). The dark gray, fine sand and silt turbidites are similar to samples from the Milano and Napoli mud volcanoes.…”

Section: Possible Southerly Sourcementioning

confidence: 79%

“…This indeed mirrors the clay mineralogical composition of the matrix of the mud volcano deposits. Cita et al (1984) argued that the terrigenous clay-rich turbidites were derived from the Nile. The origin of the calcareous turbidites was less obvious, but supply through submarine canyons on that North African slope is inferred, mainly because the Mediterranean Ridge was assumed to be a topographic barrier to supply from the north.…”

Section: Possible Southerly Sourcementioning

confidence: 99%

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Origin of clasts and matrix within the Milano and Napoli mud volcanoes, Mediterranean Ridge accretionary complex

Robertson¹,

Kopf²

1998

Proceedings of the Ocean Drilling Program, 160 Scientific Results

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Petrographic and mineralogical studies of clasts and matrix in the Milano and Napoli mud volcanoes drilled during Ocean Drilling Program Leg 160 provide important clues about depositional processes, provenance, and the tectonic setting of deepsea sediments that accumulated before genesis of the Mediterranean Ridge mud volcanoes.The clasts recovered from both mud volcanoes are mainly mudstone and claystone, calcareous siltstone, quartzose sandstone and siltstone, shallow-water-derived limestone, and pelagic carbonate. Biostratigraphic evidence indicates mainly early and middle Miocene ages for fossiliferous clasts, with the older microfossils being reworked. Textural evidence (grading) suggests that the clastic lithologies are turbidites. Sources of the sandstones were mainly plutonic igneous and subordinate metamorphic rocks. Sporadic, exceptionally well-rounded, quartz grains may be of eolian origin and were probably derived from the Precambrian basement of North Africa. Shallow-water-derived carbonates were also redeposited as calciturbidites, with variable admixing with siliciclastic and pelagic carbonate, which indicates shared depositional pathways. Pelagic carbonates (packstones) were redeposited basinward as calciturbidites from a deep-sea carbonate slope that formed part of the North African continental margin. During the middle Miocene, the background sedimentation was in situ pelagic carbonate. In addition, relatively rare, texturally immature, lithic sandstones include serpentinite, basalt, and radiolarian chert, of ophiolite-related origin. This material was derived from the orogenic areas to the north, possibly originally from the higher thrust sheets of Crete, before late Miocene and subsequent erosion and extensional downfaulting.The texture and composition of the mud and clay matrix provide clues about the mode of the mud volcanism. The matrix of the mud debris flows includes numerous, small, angular clasts of unfossiliferous claystone and shardlike fragments, which show pseudolamination, microshearing, and crosscutting veinlets, features that are taken as evidence for the involvement of high fluid pressure in clast and matrix formation (hyrofracturing).

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Section: Possible Southerly Sourcementioning

confidence: 79%

Section: Possible Southerly Sourcementioning

confidence: 99%

Origin of clasts and matrix within the Milano and Napoli mud volcanoes, Mediterranean Ridge accretionary complex

Robertson¹,

Kopf²

1998

Proceedings of the Ocean Drilling Program, 160 Scientific Results

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“…Thick structureless turbidite muds have long been reported from cores of Mediterranean troughs and basins (see references in Stanley, 1985). However, thick, laterally extensive 'megabeds' that are clearly very large-volume pounded mud turbidites have been described from the larger abyssal plains of the Mediterranean, on the western Mediterranean and Calabrian Ridges (Kastens and Cita, 1981), on the Ionian Abyssal Plain (Hieke, 1984), on the Herodotus Abyssal Plain (Cita et al, 1984 andRothwell et al, 2000), and on the Balearic Abyssal Plain (Rotwell et al, 1998 and2000).…”

Section: Abyssal Plainsmentioning

confidence: 99%

An introduction to Mediterranean deep-sea biology

et al. 2004

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“…Their internal structure generally lacks coherent reflectors and appears acoustically transparent (Embley, 1976(Embley, , 1980Jacobi, 1976;Damuth, 1980aDamuth, ,b, 1994 while their erosive base appears reflective. Transparent echo-types can also characterize basinal fine-grained turbidites (Tripsanas et al, 2004b;Cita et al, 1984), but then no erosive base is observed. -Chaotic echo-characters (C) correspond to highly disorganized sediments generally induced by mass-wasting processes such as slumping or debris flows (Pratson and Laine, 1989;Damuth, 1994).…”

mentioning

confidence: 95%

Slope instabilities from echo-character mapping along the French Guiana transform margin and Demerara abyssal plain

Loncke

Droz

Gaullier

et al. 2009

Marine and Petroleum Geology

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International audienceThe French Guiana transform margin and Demerara abyssal plain have been recently surveyed in the framework of the EXTRAPLAC French Program of extension of the continental shelf (Guyaplac survey, Ifremer-IFP–SHOM-IPEV). Based on the interpretation of some of the data collected during the Guyaplac survey (Simrad-EM12 multibeam bathymetric data, backscatter imagery, and 3.5 kHz profiles), the area can be divided into three morphostructural domains. (1) The western Guiana margin, including a part of the Demerara plateau, an important bathymetric relief prolonging the continental platform off Guiana and Surinam. This domain is bounded by (1a) the NW– SE trending northern border of the Demerara plateau which appears quite steep and corresponds to a transform segment of the margin, (1b) the N–S eastern border of the Demerara plateau which corresponds to a divergent segment of the margin. The Demerara plateau shows a segmented morphology, lowslope gradients, and a very rough surface (ripples perpendicular to the slope direction). NNW–SSE structural steps seem to correspond to collapses of 100 km long blocs towards the east. Slumps initiate along these directions. The observed rough bathymetry seems to be related to creeping processes. At a greater scale (seismic data), this part of the margin has been totally destabilized (numerous imbricate transparent masses rooted at about 0.5 s.t.w.t.t. belowseafloor). TheNW–SE trending northern border of the Demerara plateau corresponds to a cliff-like continental slope, probably slightly smoother than other transform margins (Ghana/coˆte d'Ivoire margin). The N–S eastern border of Demerara plateau is characterized by numerous small-scale imbricate slumps. Some of these failures seem to be emplaced in the prolongation of the NNW–SSE structural steps identified on the Demerara plateau. (2) The eastern Guiana margin corresponds to a NW–SE oriented gullied transform margin segment. The associated continental slope is very steep and characterized by numerous imbricate slumps and related debris lows. Some undulated masses, probably corresponding to creeping sediments or to older mass-wasting events are still imprinted on bathymetry. This transform margin segment is nearly entirely destabilized and eroded. (3) The Demerara abyssal plain. This domain is characterized eastwards by channels belonging to the Amazon turbidite system and westwards, at the foot of Demerara continental slope, by sediment waves probably created by contour currents. To conclude, it seems that there is a strong relationship between the structure (transform and divergent segments) and the emplacement of recurrent slope instabilities. These are probably related to the steepness of the slopes but also to subsidence histories generating in some cases huge deep-seated collapses of the whole margin. Fluid ascents are common everywhere in the area, probably enhancing slope instability. Their origin is not constrained but the black shales or Cretaceous organic-rich layers could be good candidates

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Turbidites and megaturbidites from the Herodotus abyssal plain (eastern Mediterranean) unrelated to seismic events

Cited by 72 publications

References 12 publications

Origin of clasts and matrix within the Milano and Napoli mud volcanoes, Mediterranean Ridge accretionary complex

Origin of clasts and matrix within the Milano and Napoli mud volcanoes, Mediterranean Ridge accretionary complex

An introduction to Mediterranean deep-sea biology

Slope instabilities from echo-character mapping along the French Guiana transform margin and Demerara abyssal plain

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