structural evolution of the latakia ridge and cyprus basin at the front of the cyprus arc eastern mediterranean sea abstract the active deformation front between the african and anatolian plates in the eastern mediterranean is delineated by the cyprus arc present plate kinematic vectors and earthquake data suggest that the movement along the eastern extent of the cyprus arc is largely sinistral strike slip it is however widely accepted that subduction took place beneath cyprus until the early miocene subduction has since thought to have become impeded by the collision of the eratosthenes seamount with the island of cyprus the deformation front of the cyprus arc is dominated by the latakia ridge a steep narrow high which merges gradually with the lower slope of the broad hecataeus rise in the west and extends to the northern levantine coast in the east where the expression of the ridge changes to a number of narrow northeast trending ridges and basins the latakia ridge has previously been interpreted as either a thrust culmination or a positive flower structure this study uses high resolution marine seismic reflection profiles to delineate the stratigraphic and structural architecture of the deformation front from seismic profiles four stratigraphic units bounded by major basin wide unconformities can be identified these units are eocene lower miocene miocene uppermost miocene messinian and pliocene quaternary the timing of deformation determined from growth stratal architectures on the flanks of the major structures show that two main phases of deformation characterize the structural history of the deformation front each of these phases represents a different kinematic regime a compressional regime dominated during the miocene whereas a strike slip regime dominated in the pliocene quaternary

rate of outward growth of the mediterranean ridge accretionary complex abstract the position as a function time of the deformation front on the southwest flank of the mediterranean ridge accretionary complex is constrained as follows 1 a the deformation front is now active 2 b the site of core ban84 05gc was still near the abyssal plain when displaced shallow water benthic foraminifera of inferred african provenance were redeposited within an upper pliocene age unit 3 c the site of core ban84 05gc on the outer flank of the mediterranean ridge was already within the topographically rugged accretionary complex when a pliocene debris flow was emplaced 4 d dsdp site 125 had already been uplifted into a topographically elevated position when lower pliocene pelagic ooze was deposited 5 e a gypsum bearing breccia in dsdp site 125 requires that the site was either on the abyssal plain or within the tectonically active outer perimeter of the accretionary complex during the messinian salinity crisis 6 f dsdp site 377 had already been uplifted into a topographically elevated position when middle miocene age pelagic marl was deposited 7 g dsdp site 377 was still on or near the abyssal plain when early to lower middle miocene age smectite bearing turbidites of inferred african provenance were deposited and 8 h the mediterranean ridge began to grow by offscraping against a backstop formed by the alpine nappes of the hellenic arc at the time that subduction began 33 ma together these constraints define a range of potential growth curves for the mediterranean ridge with a rate of outward growth of approximately 0 5 to 2 cm yr this growth rate is faster than that inferred for most other modern accretionary prisms both as an absolute value and as a fraction of the subduction velocity an unusually thick incoming section and or an unusually weak evaporitic decollement may contribute to the rapid growth rate the inferred age of accretion does not increase linearly with distance from the deformation front rather there is an apparent acceleration of the rate of outward growth through time this observation may reflect a true acceleration of growth rate in response to the onset of back arc extension in the overriding plate aegean sea and or in response to the development of a weak basal decollement following the introduction of halite into the incoming stratigraphic section alternatively the non linearity of the age vs distance curve may indicate that shortening of the offscraped sediments continues across the breadth of the mediterranean ridge rather than being confined to the outer flank

controls on the basinwide architecture of late miocene messinian evaporites on the levant margin eastern mediterranean abstract interpretation of 2d and 3d seismic data from the levant margin eastern mediterranean has revealed the complex depositional and structural setting of the basinwide late miocene messinian evaporites the data set covers a total area of 20 000 km2 permitting a semi regional investigation of the thick up to 1 8 km evaporitic wedge the sequential analysis of time structure maps isochron maps and seismic cross sections highlighted the main morphological and structural features characterizing the pre syn and post evaporitic levant margin this approach provided insights on the impact of local vs regional factors in governing the distribution of the messinian salinity crisis in the region two regional features have been recognized as the most significant controlling factors for the architecture of the messinian evaporites firstly a series of anticlines of the syrian arc foldbelt acted as a structural barrier indirectly governing the overall landward extension of the evaporites secondly submarine canyons active in the area at least since the oligocene afiq el arish and ashdod canyons represented preferential sites of erosion and deposition of evaporites our results document therefore the importance of the deep seated structures and relict drainage for the architecture of the messinian evaporites on the levant margin the new insights provided can be additionally used to infer the original depositional geometry of the evaporites in the study area and as an analogue in other mediterranean areas where 3d seismic is not available yet and sub salt imaging is limited

deformation of the western mediterranean ridge importance of messinian evaporitic formations abstract multichannel seismic data were acquired across several areas of the mediterranean ridge m r in the eastern mediterranean sea during the mcs prismed survey march 1993 the m r is a wide high standing and elongated swell emplaced between the southern aegean and africa as a consequence of the long term convergence and the ongoing collision between europe and africa sedimentary piling and associated deformation have built a thick deformed sediment wedge the internal geological structures of which remain poorly understood processing of two mcs lines pm 02 and pm 03 across the western branch of the mediterranean ridge reveals that messinian evaporite bearing formations which were deposited within the deep ionian oceanic basin 5 my ago play an important part in the present structural deformation of the m r accretionary wedge within the outer m r the messinian lower evaporites are believed to act as one of the main decollement levels while the top of these formations may operate as a disharmonic layer below thin plio quaternary sediments the present day m r toe appears to be affected by ductile flow deformation however most of the accreted outer wedge is believed to have resulted from the progressive piling up and associated thrusting of messinian and overlying plio quaternary sediments toward the northeast i e toward the central m r domain a major backthrust zone indicates a structural boundary between the outer wide and convex m r and its inner rather flat domain which is inferred to act as a backstop

stratigraphy of the western mediterranean and southern calabrian ridges eastern mediterranean abstract the present paper illustrates the stratigraphic results of a transponder navigated coring program carried out in 1978 on the southern calabrian ridge cobblestone area 4 and western mediterranean ridge cobblestone area 3 semi quantitative investigations of over 600 foraminiferal samples and 450 nannofossil slides from forty cores with a total recovery of 333 m comprise the data base of the study most of the sediments recovered are late pleistocene or holocene in age the high resolution nannofossil biostratigraphic scheme recently proposed for the quaternary coupled with sapropel stratigraphy and with tephrachronology resulted in precise correlation of the cores mid pleistocene sediments were recovered in a single core from area 4 and in one core from area 3 both located on basin walls four cores from basin walls in area 4 yielded pliocene sediments no sediments older than approximately 3 m y foraminiferal zone m pl 4 reticulofenestra pseudoumbilica nannofossil zone are exposed on the explored walls from the southern calabrian ridge early and late pliocene sediments were recovered from the walls of the deepest crater like basin explored in area 3 but only in dredges in this latter area also two peculiar lithologies were cored basically unfossiliferous but thought to be pre pliocene in age a mud breccia whose clasts yield a sparse assemblage of mid cretaceous planktonic foraminifera and a dolomitic mudstone which is attributed to the late messinian on the basis of correlation with a similar lithology cored at dsdp site 374 and substantiated by analogy in x ray controlled mineralogical composition the fairly complete record of late pleistocene and holocene sapropels recovered in the southern calabrian ridge discards the hypothesis that the southern part of the ionian sea did not undergo stagnant cycles during the ice ages another hypothesis relating the origin of cobblestone topography to olistostromes is also considered untenable on the basis of the new data the large number of cores precisely located on a previously mapped highly irregular bottom physiography disproves that large scale chaotic sedimentation occurred debris flows recorded in base of slope cores document local slope failures

the temporal and spatial development of landslides in the axmouth lyme regis undercliffs national nature reserve devon a chronology of landsliding is presented including suggestions as to a date for initiation periods of activity known from historical sources are correlated with known periods of climatic deterioration the current morphology of the landslide slopes is closely related to the geological succession and structure these permit the landslides and their development to be differentiated on the basis of whole slope and toe morphology and much of the whole slope activity can be related to conditions at the toe examples of geomorphological maps slope categories maps and cross sections are presented along with an example of the evolutionary maps which may be derived from ordnance survey plans and aerial photographs these generally indicate that weakening of materials by weathering seepage erosion at the toe and marine erosion result in frequent mass movement events of a low magnitude these events ultimately influence the stability of larger slipped blocks behind which fail less frequently it is suggested that whole slope failures in this region have a maximum frequency of once in 120 to 150 years and that problems of interpretation of historical accounts may mean that it is very much less frequent than this

evidence of relief inversion from the rim syncline of bannock basin abstract the last steps in the geological exploration of bannock basin cruises ban 88 and ban 89 of r v bannock provided direct evidence of an inversion of relief that was long suspected but hitherto never recorded dolostones and dolomitic mudstones of probable messinian age subcropping beneath the brine in the northern part of bannock basin and zanclean oozes recorded on the sill separating two narrow and elongate satellite basins along the eastern part of the rim syncline record a relief inversion during their evolution from cylindric folds to collapse structures in particular the core from the eastern intrabasin sill contains two major unconformities one separates early zanclean oozes from late piacenzian pelagic sediments characterized by winnowed layers inclined bedding and incipient hardgrounds and the second separates the latter from middle pleistocene pelagic sediments the deepening is certainly post late piacenzian post m pl 6 biozone because sediments of that age record an actively uplifting structure another argument in favour of the relief inversion and of the youthful age of the deepening is derived from a core raised from the northern part of the major western basins large sill separating maestro from borea basins which contains a coarse turbidite of north african origin representing an upflow turbidite similar to others recorded on the outer slopes of the mediterranean ridge this unique finding in the area of bannock basin is preserved in the central part of the collapse basin whereas in other settings an erosional gap is noticed at the equivalent stratigraphic position

setting and tectonic evolution of some eastern mediterranean deep sea basins abstract nine discrete deep sea basins seven from the calabrian and mediterranean ridges and two from the strabo trench were explored geologically during several cruises carried out from 1978 to 1984 in the eastern mediterranean the seven basins displaying similar geological features calabrian and mediterranean ridges may be divided into three groups on the basis of their size 1 very small basins botticelli and raffaello basins whose area ranges from 1 1 to 4 3 km 2 2 small basins ares aphrodite and katia basins from 7 to 13 km 2 and 3 large basins bannock and cleft basins from 22 to 74 km 2 the two basins from the strabo trench tyro and kretheus basins whose areas range from 16 to 20 km 2 are considered separately tectonics is the most important element affecting basin formation processes progressive folding and faulting of messinian pliocene and quaternary sediments in the calabrian and mediterranean ridges allows the infiltration of water into the subbottom and dissolution of messinian evaporites so that collapse of the overlying unconsolidated plio quaternary cover creates local distensive tectonics superimposed on the regional compressive tectonic setting the size of the basins reflects different steps in this process very small basins are related to the fracturing occurring at the top of anticlines small basins originate when anticlines are faulted and large amounts of water are able to reach the evaporites and increase the intensity of leaching finally large basins are related to regional tectonic lineaments both compressive large reverse faults overthrusts and strike slip salt diapirism may be associated with some of these situations the process responsible for the tyro and kretheus basins formation is the pull apart mechanism connected with the strike slip motion occurring in that area the geometric position of subaqueously dissolved evaporites seems to influence the environment on the basin floor brines originating from the dissolution of buried evaporites are thought to disperse in the subbottom whereas brines originating from dissolution of evaporites cropping out on the basin walls can flow to the floor and cause stagnation only if the shape of the basin prevents the action of bottom currents

stratigraphy and sedimentation in the anoxic bannock basin eastern mediterranean abstract ten gravity and or piston cores raised from the floor and the eastern flank of the bannock basin and from nearby plateaus were investigated lithologically and biostratigraphically the bannock basin is a large rimmed depression with a vertical relief of over 600 m containing deep seated brines the brines are derived from submarine dissolution of messinian evaporites in a physiographic setting deep rimmed basin that does not permit dilution and removal by bottom currents plateau cores range in age from holocene emiliania huxleyi acme zone to middle pleistocene pseudoemiliania lacunosa zone they consist of low sedimentation rate pelagic sediments with sapropels and tephras as minor isochronous lithologies two cores on the flanks recovered pliocene pelagic sediments one of these cores displays an unconformable contact between holocene anoxic sediments and early pliocene reticulofenestra pseudoumbilica zone marls the other core is entirely pliocene consisting of a debris flow with a matrix that is referred to the discoaster tamalis subzone cores from the deeper part of the basin consist of laminated non bioturbated poorly oxygenated dark sediments rich in h 2 s and containing large gypsum crystals organic carbon content is higher than in normal eastern mediterranean pelagic sediments but lower than in true sapropels the kerogen is dominated by amorphous organic matter although the oxygen content of the bottom waters was not measured sedimentary evidence suggests that poorly oxygenated but not entirely anoxic conditions exist in the basin at the sediment water interface in particular benthic foraminifers would be much less abundant than they actually are and org c content would be higher if bottom waters were anoxic poor oxygenation started to develop in the bannock basin some 180 ka b p after the deposition of sapropel s 6 as documented in core 84 02 this long lasting period of anoxia strongly differs from the short anoxic episodes in the eastern mediterranean that were controlled by glacial interglacial changes the bannock basin anoxia is a result of brine formation causing strong density stratification with a density contrast 20 that is much higher than the density contrast derived from changes in thermohaline circulation during glacial interglacial times during these eastern mediterranean basin wide euxinic episodes the boundary between oxygenated and anoxic waters was much shallower than the 3200 m interface recorded in the bannock basin reworked and displaced foraminiferal faunas were found in the pliocene sediments recovered in the flank cores in particular the occurrence of abraded tests of the shallow water form elphidium spp of bulimina costata and of other displaced taxa does suggest that the area was subject to deposition by turbidity currents originating on the african margin and that in pliocene times no rimmed basin was in existence

turbidites and megaturbidites from the herodotus abyssal plain eastern mediterranean unrelated to seismic events abstract a transect of 9 piston and gravity cores was taken across the southeast flank of the mediterranean ridge the transect extends from the abyssal plain to a location 290 m shallower than the abyssal plain and 50 km north of the edge of the ridge each core contains two or more turbiditic layers which belong to two discrete types here called a and b type a essentially consists of black plastic clays rich in smectite with silt fraction of terrigenous nature source area is the nile cone and age is middle or late pleistocene type b turbidites are pale brown to whitish in color coarse grained carbonate rich and bioclastic in composition with shallow water fossils dominant they are poor in smectite and the silt fraction is very rich in carbonates calcite and aragonite the source area is the north african shelf south of the abyssal plain a megabed belonging to type b turbidites is correlatable from core to core with a thickness in excess of 10 m in the abyssal plain and an estimated volume of 10 km 3 its stratigraphic position in the latest pleistocene suggests that its origin is related to a sudden collapse of bioclastic sediments accumulated in a canyon head during a low sea level stand the source areas of the two discrete turbidite types belong to the essentially aseismic north african continental margin although they are presently recorded on the tectonically active mediterranean ridge no seismic events are required to account for the presence of either type of turbidite

gypsum precipitation from cold brines in an anoxic basin in the eastern mediterranean in 1968 hot brines from which gypsum had precipitated were discovered in the red sea in a divergent plate boundary setting with hydrothermal activity1 we now report the discovery of cold brines in an entirely different geodynamic situation a convergent plate boundary in the eastern mediterranean where the heatflow is very low2 and no hydrothermal activity occurs decimetric pure gypsum crystals precipitate from the cold brines which occupy the bottom of a rimmed anoxic basin near the southern edge of the mediterranean ridge close to the sirte abyssal plain nucleation of the crystals does not occur at the surface but from the deep brines because the salinity of the water is normal down to the depth of 3 000 m we propose the name bacino bannock for this basin after the consiglio nazionale delle ricerche r v bannock from which the bottom water brines were surveyed and sampled

a subducting seamount beneath the mediterranean ridge abstract two transverse morphological tracks across the front of the mediterranean ridge were swath mapped with a hydrosweep instrument system along the tracks ridges and troughs at the front of the accretionary prism are disrupted and bent in the direction of relative plate convergence the longer of the two tracks extends to bannock basin a brine filled depression with a closed outer moat around a central mound seismic reflection data and a gravity anomaly show a buried circular seamout beneath bannock basin whose summit is the mound this indicates an origin of the larger transverse track and bannock basin from a subducting seamount beneath bannock basin the seamount has displaced about 340 km 3 of the messinian section and yet the seafloor has not been uplifted therefore considerable evaporitic material is inferred to have been displaced by the seamount and bannock basin is a likely vent for large quantities of dissolved materials from the disrupted messinian evaporitic sequence

the eastern hellenic margin from crete to rhodes example of progressive collision abstract available geological and geophysical data from the eastern hellenic outer margin between eastern crete and rhodes have been interpretated and analyzed the data support the hypothesis of a progressive continental collision between the aegean domain and the african intermediate crust the resulting geological structures are compared with similar features generated elsewhere in response to crustal shortening based on distribution of epicenters bathymetry two separate and sublinear troughs and seismic profiles we propose an evolution of the area in two main episodes an activation of the margin in the upper miocene and a progressive collision starting in the pliocene

salt tectonics driven by sediment progradation part ii radial spreading of sedimentary lobes prograding above salt experimental models indicate that sedimentary lobes deposited above mobile evaporites deform gravitationally by spreading outward radially radial spreading forms both concentric and radial families of thin skinned grabens that are then pierced diapirically by salt ridges the overburden blocks located between the ridges become subsiding depocenters later continued spreading after depletion of the salt layer forces salt ridges and diapirs to fall forming rapidly subsiding bathymetric lows that channel or trap younger sediments spreading causes large horizontal overburden movements whose distribution and orientation change when the locus of regional deposition shifts

stratigraphy and sedimentation in the western strabo trench eastern mediterranean abstract three piston cores ranging in length from 501 to 921 cm raised from the adjacent mediterranean tyro and kretheus basins and their intervening sill confirmed previous findings of persistent anoxia and extended our knowledge of the stratigraphic record the two cores from the basinal settings contain a bronze age homogenite this tsunami induced turbidite is only 28 cm thick in the shallower kretheus basin whereas it has a thickness of 235 cm in the deeper tyro basin the recovery of the homogenite in these subbasins of the western strabo trench demonstrates that the tsunami wave turned west of crete and arrived here with a velocity sufficient to remobilize unconsolidated sediments draping the basin slopes the holocene and uppermost pleistocene sedimentary record is characterized by numerous millimetric to centimetric sand layers containing reworked pliocene and miocene foraminifers the repetitive siliciclastic turbidites interfered with the normal eastern mediterranean succession of sapropels and tephras and document a strong neotectonic activity related to the presence of an active trench on the floor of ponded rimmed basins like the tyro and kretheus basins the sand layers are associated with anoxic sediments whereas they are associated with normal well oxygenated marls on the sill which lies above the anoxic oxic interface basin anoxia is interpreted as the result of submarine dissolution of messinian evaporites giving rise to deep seated brines extraformational reworking documents the occurrence of pre messinian fossiliferous sediments exposed on the trench wall and subject to submarine erosion the stratigraphic time framework is given by nannofossil biostratigraphy corroborated by lithostratigraphic correlation of isochronous lithologies sapropel and tephra chronology a drastic change in sedimentary regime is recorded at approximately 70 ka b p emiliania huxleyi acme e huxleyi zonal boundary older sediments which were only recovered in core 37 from the sill separating the tyro and kretheus basins are pelagic with an almost typical eastern mediterranean succession of sapropels and tephras no siliciclastic turbidites and no extraformational reworking are noticed in sediments older than 70 000 years we conclude that the trench system became active just at that time a thick layer of plurimillimetric pumice bubbles was discovered within sapropel s 6 indicating a strong explosion of a nearby volcano at 180 ka b p but we have no analytical data yet to substantiate the provenance of the volcanogenic deposits

global positioning system constraints on plate kinematics and dynamics in the eastern mediterranean and caucasus we present and interpret global positioning system gps measurements of crustal motions for the period 1988 1997 at 189 sites extending east west from the caucasus mountains to the adriatic sea and north south from the southern edge of the eurasian plate to the northern edge of the african plate sites on the northern arabian platform move 18 2 mm yr at n25 5 w relative to eurasia less than the nuvel 1a circuit closure rate 25 1 mm yr at n21 7 w preliminary motion estimates 1994 1997 for stations located in egypt on the northeastern part of africa show northward motion at 5 6 2 mm yr also slower than nuvel ia estimates 10 1 mm yr at n2 4 e eastern turkey is characterized by distributed deformation while central turkey is characterized by coherent plate motion internal deformation of 2 mm yr involving westward displacement and counterclockwise rotation of the anatolian plate the anatolian plate is de coupled from eurasia along the right lateral strike slip north anatolian fault naf we derive a best fitting euler vector for anatolia eurasia motion of 30 7 0 8 n 32 6 0 4 e 1 2 0 1 myr the euler vector gives an upper bound for naf slip rate of 24 1 mm yr we determine a preliminary gps arabia anatolia euler vector of 32 9 1 2 n 40 3 1 1 e 0 8 0 2 myr and an upper bound on left lateral slip on the east anatolian fault eaf of 9 1 mm yr the central and southern aegean is characterized by coherent motion internal deformation of 2 mm yr toward the sw at 30 1 mm yr relative to eurasia stations in the se aegean deviate significantly from the overall motion of the southern aegean showing increasing velocities toward the trench and reaching 10 1 mm yr relative to the southern aegean as a whole

abnormal carbonate diagenesis in holocene late pleistocene sapropel associated sediments from the eastern mediterranean evidence from emiliania huxleyi coccolith morphology in studying the holocene late pleistocene record of the eastern mediterranean considerable emiliania huxleyi size shape variation not clearly assignable to primary or secondary calcification was observed accordingly different morphotypes were distinguished by light microscope lm a subsequent scanning electron microscope sem analysis of selected samples has indicated that emiliania huxleyi coccoliths are variably affected by carbonate diagenesis in these sediments a series of diagenetic stages were qualitatively defined comprising well preserved specimens three overgrowth og1 to og3 and one etching e1 stage comparing sem and lm observations a tentative correlation between the e huxleyi calcified lm morphotypes and e huxleyi sem overgrowth stages is proposed here our study not only indicates that emiliania huxleyi coccoliths are strongly influenced by carbonate diagenesis but also that they show effects of carbonate precipitation and dissolution much more clearly than other coccoliths the relative abundances of the different lm morphotypes were used to define an e huxleyi overgrowth index exo that qualitatively estimates carbonate precipitation dissolution on coccoliths in this sediment this resulted in definition of five diagenetic intervals d1 to d5 deposition of sapropel s1 was a time of good preservation with variable dissolution and no overgrowth of e huxleyi coccoliths whereas calcite overgrowth was high during the last glacial maximum lgm and interglacial period and to a lesser extent during the younger dryas and through the last 5 ka d 2004 elsevier b v all rights reserved

quaternary crusts on slopes of the mediterranean sea a tentative explanation for their genesis abstract quaternary deep sea crusts i e lithified omission surfaces are widespread on slopes and subsea relief features in the western and especially the eastern mediterranean sea the lithification is induced by the early precipitation of a magnesian calcite cement in the uppermost few centimetres of a calcareous ooze based on their thickness and degree of hardening the collected samples have been divided into three main types each of them corresponding to a different degree of lithification except in rare probably old crusts collected at water depths below 2000 2500 m and in infills of some sponge skeletons or in the case of inferred internal tension recrystallization and generally mineral alterations are very limited the precipitation mechanisms appear to be essentially physicochemically controlled and ions involved in cementation come from the seawater reservoir by means of an inward diffusion of solutions diffusion is enhanced by bottom currents these currents maintaining a low or zero rate of sedimentation moreover lithification also depends on the chemical characteristics of the seawater i e supersaturation with respect to low magnesian calcite and low contents of phosphates and dissolved organic matter which would inhibit crystal growth local factors and primary composition of the original sediment also appear to influence the speed of early lithification when conditions of lithification are favourable a few hundreds of years to a few thousand years at the most seem sufficient for the first two stages of lithification to be reached the submarine lithification was active during the last glacial episode and as exhibited by numerous samples especially towards the end of this period the previous cold stages were probably also episodes of efficient lithification this correlation with quaternary climatic cycles certainly reflects an intensification of thermohaline and bottom current circulations during periods of severe climatic conditions there is also some evidence of holocene and even present day crusts

post messinian evolution of the florence ridge area western cyprus arc part i morphostructural analysis abstract the florence ridge part of the western cyprus arc is a compressional relief that was eroded during the messinian salinity crisis while deposition of salt occurred north antalya basin and south herodotus abyssal plain in order to better assess the impact of salt tectonics in the florence ridge region deformations we conducted a morpho structural analysis of available multibeam and seismic data simed and prismed ii campaigns it is indeed a crucial issue to distinguish crustal and gravity driven structures in the compressional to strike slip belts of the eastern mediterranean along the antalya basin we mainly observed multi directional tectonic rafts typical of gravity gliding above salt on the florence ridge itself the base of salt evolves laterally to a messinian erosional surface that erodes a series of stacked nappes this surface is involved in recent faulting south of the florence ridge a nearly 100 km wide fold belt characterizes the herodotus abyssal plain three different zones parallel to the florence ridge appear within this fold belt those are respectively from north to south zones a b and c zone a is characterized mainly by small wavelength folding and faulting approaching zone b a long extensional graben deforms the seafloor zone b stands 100 to 200 m higher than zones a and c there salt welding seems common in the easternmost zone b deep sub circular bathymetric depressions are associated with extremely thick and fan shaped depocenters probably emplaced in relation with active sub salt thrusts many evidences suggest post messinian uplift in this zone zone c shows medium to high wavelength salt cored folds wavelength of those folds increase approaching the distal nile deep sea fan within zone c a nearly undeformed domain exists approaching the eratosthenes seamount en echelon folds bound this flat domain suggesting lateral salt extrusion at the junction between zone c and the distal nile deep sea fan to conclude numerous evidences argue for a post messinian reactivation of the pre messinian florence ridge accretionary wedge numerous folds uplifted zones the salt as on the nearby mediterranean ridge decouples deep and surface deformations and even allow the development of isolated grabens and associated salt ridges in the heart of the florence compressional zone we propose in this case that local basal slope of salt increase related to basement fault activity triggered gravity gliding and thus extensional deformation despite the regional compressional regime finally this study shows that the eastern nile deep sea fan submitted to extremely vigorous salt tectonics seems to have collided with the florence ridge fold belt and to have generated a salt extrusion zone