on the post 25 ma geodynamic evolution of the western mediterranean during the neogene and quaternary western mediterranean geodynamics were dominated by the eastward migration of the apenninic arc and associated back arc basins the migration was controlled by retreat of the apenninic slab and was associated with boudinage of the lithosphere in the back arc area palaeo reconstruction of the kinematics of the arc suggests about 775 km of migration from the late oligocene to present along a transect from the gulf of lions to calabria a maximum of 135 km of n s converge occurred between africa and europe during the same time span the western mediterranean was thus mainly shaped by the migration of the slab related to west directed subduction it is hypothesized that minor n s convergence deformed the arc but was not the cause of its formation 1998 elsevier science b v all rights reserved

paleomagnetism of jurassic to miocene sediments from the apenninic carbonate platform southern apennines italy evidence for a 60 counterclockwise miocene rotation abstract the tectonic evolution of the apennine belt southern tyrrhenian sea system is addressed through a paleomagnetic study of lias to langhian sediments from the apenninic carbonate platform southern apennines italy reliable paleomagnetic data gathered from 21 sites document a regional scale post langhian 80 counterclockwise ccw rotation since previous studies of the plio pleistocene clays spread over the orogen had shown a 20 ccw rotation we conclude that the southern apennines rotated by 60 during middle late miocene our data provide evidence that the southeastward drift of calabrian block and synchronous spreading of the southern tyrrhenian sea induced saloon door like deformation of the southern apennines and sicily which underwent similar magnitude although opposite in sign orogenic rotations a paleomagnetically derived paleogeographic reconstruction shows that at 15 ma late langhian the alpine apennine belt collided with a nne oriented carbonate platform corridor surrounded by oceanic basins we speculate that both the end of the corsica sardinia rotation and the eastward jump of the locus of back arc extension from the liguro provencal to the tyrrhenian sea may have been consequences of this event

synsedimentary tectonic soft sediment deformation and volcanism in the rifted tethyan margin from the upper triassic middle jurassic deep water carbonates in central sicily abstract the pizzo lupo section sicanian mts central sicily is an upper triassic lower jurassic condensed deep water succession where the relationships among synsedimentary tectonic soft sediment deformations volcanism and lithological changes reflect the evolution of a rift basin the morphostructural setting of the studied basin appears as a gently dipping slope where a fault delimited area graben to halfgraben was developed the instability of the sea floor related to the seismic shocks was the cause of the gravity driven deformational sedimentary structures slumping breccia channelized bodies the partly stratified basaltic rocks with disorganized and chaotic stratification suggest the occurrence of a volcanic complex located in neighbouring areas a regional comparison with the tectono sedimentary evolution of the pelagic drowning platform succession i e trapanese domain auct outcropping in adjacent areas suggests that these different domains were close to each other during the studied period forming a stepped margin platform to basin system the environmental changes synsedimentary tectonic activity and gravity driven phenomena were the result of repeated events occurred during a long time interval spanning from late triassic to early jurassic

paleoclimate and extensional tectonics of short lived lacustrine environments lower cretaceous of the panormide southern tethyan carbonate platform nw sicily abstract subaerial erosion and continental sedimentation interbedded with shallow water carbonates are unequivocal stratigraphic records to evaluate paleoenvironmental and paleoclimate evolution of emerged landmass stratigraphic analysis of the cretaceous monte gallo section of the mesozoic panormide carbonate platform in the northern side of the palermo mountains nw sicily records a peculiar continental derived clays that interrupted the shallow water carbonate sedimentation these clays rest with lenticular geometries above the tectonically enhanced subaerial erosional unconformity of the barremian lower aptian requienid limestones and are covered by the upper cretaceous rudistid limestone sedimentological investigation combined with mineralogical and petrographic results reveal the occurrence of alkaline to saline lake clays deposition in pond filling depositional environment recording stressed conditions evaporation especially in its final living phase they were formed when a half graben tilted block tectonics produced footwall uplift of the gallo faulted blocks carbonate platform paleoclimate evaluations of the continental derived clays highlighted that a period of warm humid conditions which favoured their formation interrupted the uniform warm climate conditions highlighting a greenhouse climate phase

volcanic ash layers in the upper cretaceous of the central apennines and a numerical age for the early campanian at montagna della maiella and at gola del furlo central apennines two discrete layers of bentonic clay are intercalated within the pelagic furlo and turbiditic pelagic limestones maiella of the upper cretaceous basinal succession of the umbrian basin scaglia facies the bentonite layers are dated by planktonic foraminifera to the globotruncanita elevata zone early campanian and by calcareous nannofossils to the aspidolithus parcus zone cc 18 they fall into the reversed interval of chron 33 detailed correlation shows the layers to be of exactly the same age the upper layer is dated by u pb on magmatic zircons to 81 67 0 21 ma an age compatible with the cretaceous time scale of obradovich the mineralogy of the bentonitic clays is almost pure montmorillonite and contrasts sharply with the clay mineral assemblage of the enclosing pelagic and turbiditic limestones which is dominated by soil derived smectite and illite in different proportions the bentonite seams are interpreted as the submarine alteration products of wind borne volcanic ashes they can be followed with only minor changes in thickness over 200 km and must be derived from distant volcanic sources and related to extreme volcanic events a possible source area is present in the dinarides where upper cretaceous subduction related magmatic rocks are widespread

onset of submarine debris flow deposition far from original giant landslide submarine landslides can generate sediment laden flows whose scale is impressive individual flow deposits have been mapped that extend for 1 500 km offshore from northwest africa these are the longest run out sediment density flow deposits yet documented on earth this contribution analyses one of these deposits which contains ten times the mass of sediment transported annually by all of the world s rivers understanding how this type of submarine flow evolves is a significant problem because they are extremely difficult to monitor directly previous work has shown how progressive disintegration of landslide blocks can generate debris flow the deposit of which extends downslope from the original landslide we provide evidence that submarine flows can produce giant debris flow deposits that start several hundred kilometres from the original landslide encased within deposits of a more dilute flow type called turbidity current very little sediment was deposited across the intervening large expanse of sea floor where the flow was locally very erosive sediment deposition was finally triggered by a remarkably small but abrupt decrease in sea floor gradient from 0 05 degrees to 0 01 degrees this debris flow was probably generated by flow transformation from the decelerating turbidity current the alternative is that non channelized debris flow left almost no trace of its passage across one hundred kilometres of flat 0 2 degrees to 0 05 degrees sea floor our work shows that initially well mixed and highly erosive submarine flows can produce extensive debris flow deposits beyond subtle slope breaks located far out in the deep ocean

increased ice losses from antarctica detected by cryosat 2 we use 3 years of cryosat 2 radar altimeter data to develop the first comprehensive assessment of antarctic ice sheet elevation change this new data set provides near continuous 96 coverage of the entire continent extending to within 215 km of the south pole and leading to a fivefold increase in the sampling of coastal regions where the vast majority of all ice losses occur between 2010 and 2013 west antarctica east antarctica and the antarctic peninsula changed in mass by 134 27 3 36 and 23 18 gt yr 1 respectively in west antarctica signals of imbalance are present in areas that were poorly surveyed by past missions contributing additional losses that bring altimeter observations closer to estimates based on other geodetic techniques however the average rate of ice thinning in west antarctica has also continued to rise and mass losses from this sector are now 31 greater than over the period 2005 2010

the southernmost margin of the tethys realm during the mesozoic and cenozoic initial geometry and timing of the inversion processes 1 along the northern border of africa pangea breakup has been diachronic during the jurassic the alpine tethys propagated northeastward from the atlantic to the alps during the permian the neo tethys propagated westward from oman to northwestern arabia then a secondary and late branch of neo tethys gave birth to the east mediterranean basin finally the two oceans connected at end of jurassic times achieving the development of africa northern plate boundary by the late cretaceous convergence between africa and eurasia led to the progressive closure of the tethys realm the continental collision is not completely achieved and the different segments of the confrontation zone maghreb central and east mediterranean zagros and oman expose different stages of the process however we emphasize the existence of synchronous geodynamic events from one end of the system to the other although they do not have the same meaning two of them are particularly important the campanian santonian c s event corresponds to 1 obduction and exhumation of high pressure low temperature metamorphic rocks around the arabian promontory 2 inversion along the margins of the east mediterranean basins and 3 lithosphere buckling in the atlas system maghreb and adjacent sahara platform the middle late eocene mle event corresponds to 1 the onset of collision at the northern corner of arabia 2 the onset of slab retreat in the mediterranean and 3 inversion along the margin of the east mediterranean as well as in the atlas the c s event coincides with a change in plate kinematics resulting in an abrupt increase of convergence velocity the mle event coincides with a period of strong coupling between the africa and eurasia plates and an abrupt decrease of convergence velocity in the middle of the system the central mediterranean seems to escape to the effects of convergence and is the site of quite permanent extensional movements since the triassic

lithospheric bulges recorded by regional unconformities the case of mesozoic tertiary apulia abstract cyclic shallow water carbonate sequences in the cretaceous of southern italy are punctuated by regional unconformities associated with bauxites and palaeokarst features direct and indirect evidence strongly suggests that despite their apparent plate interior position tectonics rather than eustasy was responsible for subaerial exposure long enough to form bauxites in plane stress related lithospheric arching caused by orogenic deformation along the distant active margins of apulia is invoked to explain the vertical stacking of a series of regional unconformities one of them marked by bauxites on land and under the sea the case history of apulian bauxites associated with a turonian arching allows a first estimate of the duration of a stress related distant perturbation of a subsiding passive continental margin

the stratigraphic record and processes of turbidity current transformation across deep marine lobes sedimentary facies in the distal parts of deep marine lobes can diverge significantly from those predicted by classical turbidite models and sedimentological processes in these environments are poorly understood this gap may be bridged using outcrop studies and theoretical models in the skoorsteenberg formation south africa a downstream transition from thickly bedded turbidite sandstones to argillaceous internally layered hybrid beds is observed the hybrid beds have a characteristic stratigraphic and spatial distribution being associated with bed successions which generally coarsen and thicken upward reflecting deposition on the fringes of lobes in a dominantly progradational system using a detailed characterization of bed types including grain size grain fabric and mineralogical analyses a process model for flow evolution is developed this is explored using a numerical suspension capacity model for radially spreading and decelerating turbidity currents the new model shows how decelerating sediment suspensions can reach a critical suspension capacity threshold beyond which grains are not supported by fluid turbulence sand and silt particles settling together with flocculated clay may form low yield strength cohesive flows development of these higher concentration lower boundary layer flows inhibits transfer of turbulent kinetic energy into the upper parts of the flow ultimately resulting in catastrophic loss of turbulence and collapse of the upper part of the flow advection distances of the now transitional to laminar flow are relatively long several kilometres suggesting relatively slow dewatering several hours of the low yield strength flows the catastrophic loss of turbulence accounts for the presence of such beds in other fine grained systems without invoking external controls or large scale flow partitioning and also explains the abrupt pinch out of all divisions of these sandstones estimation of the point of flow transformation is a useful tool in the prediction of heterogeneity distribution in subsurface systems

deposits of flows transitional between turbidity current and debris flow the relationship between submarine sediment gravity flows and the character of their deposits is poorly understood annular flume experiments were used to investigate the depositional dynamics and deposits of waning sediment laden flows decelerating fast 3 m s flows with fixed sand content 10 vol and variable mud content 0 17 vol resulted in only four deposit types clean sand with a mud cap that resembled a turbidity current deposit turbidite formed if the flow was turbulent when deposition began or if the muddy fluid had insufficient strength to suspend the sand the clean sand could contain structures if mud content was low 300 s ungraded muddy sand with a mud cap that resembled a debris flow deposit debrite formed if the flow became laminar before sand could deposit clean sand overlain by ungraded muddy sand and a mud cap formed either from a transitional flow or by late stage settling of sand from a muddy suspension these deposits resemble enigmatic submarine flow deposits called linked debrite turbidites the experiments provide a basis for inferring flow type from deposit character for submarine sediment laden flows

biomediation of submarine sediment gravity flow dynamics the australian government research training program scholarship funded craig s ph d candidature an international association of sedimentologists postgraduate award grant funded craig s visit to bangor university bangor uk the uk natural environment research council grant ne 1027223 1 cohbed project enabled this research to be undertaken using the flume facility built by rob evans bangor university

a classification of clay rich subaqueous density flow structures this study presents a classification for subaqueous clay laden sediment gravity flows a series of laboratory flume experiments were performed using 9 15 and 21 sediment mixture concentrations composed of sand silt clay and tap water on varying bed slopes of 6 8 and 9 5 and with discharge rates of 10 and 15 m3 hr in addition to the characteristics of the boundary and plug layers which have been previously used for the classification of open channel clay laden flows the newly presented classification also incorporates the treatment of the free shear layer the flow states within the boundary and free shear layers were established using calculation of the inner variable self similarity considerations and the magnitude of the apparent viscosity based on the experimental observations four flow types were recognized 1 a clay rich plug flow with a laminar free shear layer a plug layer and a laminar boundary layer 2 a top transitional plug flow containing a turbulent free shear layer a plug layer and a laminar boundary layer 3 a transitional turbidity current with a turbulent free shear layer no plug layer and a laminar boundary layer and 4 a fully turbulent turbidity current a connection between the emplaced deposits and the relevant flow types is drawn and it is shown that a froude number two reynolds numbers and a dimensionless yield stress parameter are sufficient to associate an experimental flow type with a natural large scale density flow

submarine transitional flow deposits in the paleogene gulf of mexico gravity driven flows on the seafloor are the largest yet least well understood sediment transport agents on earth recent exploration wells in ultradeep basins have revealed the presence of large sandy submarine fan systems of enigmatic facies types many hundreds of kilometers from paleocoastlines these sedimentary deposits often defy conventional turbidite or debrite interpretations having a character suggestive of deposition from flows with transient turbulent laminar rheologies in the wilcox formation gulf of mexico inferred transitional flow deposits have distinctive stratigraphic stacking patterns from fine grained debrites to coarser grained turbidites the vertical sequence of beds is here inferred to reflect the longitudinal bed distribution in response to lobe progradation and demonstrates a transition from well mixed turbulent flow to progressively more rheologically stratified flow and eventually to fully laminar flow the progressive development of internal rheological boundaries resulted in a high concentration but fluidal basal layer and an upper quasi laminar layer with an overriding sheared dilute turbidity current the long runout of the flows is linked to their high silt and clay content it is most likely flow expansion at the channel lobe transition that drives flow transformation this process based model may be applicable to many deep water settings and provides a framework within which to interpret the stratigraphic and spatial distribution of these complex deposits

field expressions of the transformation of debris flows into turbidity currents with examples from the polish carpathians and the french maritime alps various transformation mechanisms can generate turbidity currents from subaqueous debris flows different transformation mechanisms have been described and interpreted in the past from laboratory experiments and from deposits but the two approaches have not generally been linked this has made the genetic interpretation and comparison of deposits difficult in this paper a generic classification scheme of debrite turbidite couplets is proposed based on transformation mechanisms inferred from laboratory experiments five different flow types called a e herein and their resulting deposits are detailed but they are all part of a continuous spectrum and a mixture of types is likely to be found in the field type a flows are strong dense debris flows that undergo little transformation their deposit will be a debrite overlain by a thin turbidite which is separated from it by a clear grain size break type b flows are weaker and can develop waves at the debris flow turbidity current interface the deposit will be a debrite with a wavy top overlain by a turbidite that is thicker than for type a flows for type c flows the interfacial waves will grow so much that the debris flow disintegrates into separate parts the deposit will consist of debrite lenses encased in a turbidite type d flows will undergo even more mixing than type c flows so that the debrite parts will be mixed their deposit will be a turbidite with laterally varying areas of debrite characteristics near the bed type e flows will be so transformed that the debris flow character has disappeared and the flow is a turbidity current with high sediment concentration the deposit will be largely turbiditic the flow types and deposits will be illustrated with some examples from two field areas the polish carpathians and the french maritime alps

paleoclimatic conditions and paleoweathering processes on mesozoic continental redbeds from western central mediterranean alpine chains abstract chemical and mineralogical analyses of the triassic to lowermost jurassic mudstones from continental redbeds outcropping in the internal domains of the betic rifian and calabria peloritani chains have been used to infer the relationships between paleoclimatic conditions and paleoweathering processes during rifting of a continental crust block that finally detached from adjoining western tethyan realms to form an independent microplate mesomediterranean microplate from jurassic to lower miocene time the studied mudstone samples come from middle triassic and upper triassic beds of the saladilla formation both in the betic cordillera and in the rif whereas the calabria peloritani arc studied mudstones come from upper triassic to lowermost jurassic beds both in the sila and longi taormina units major and trace element concentrations based on the mass balance calculation relative to the upper continental crust show negative values both in gibraltar and calabria peloritani arcs implying that mudstone formation in the early mesozoic involved moderate to intense continental paleoweathering of the crust in particular cao na 2 o mgo sr ba fe 2 o 3 mno and transition metal elements v cr co and ni are more depleted in the triassic to upper jurassic samples of the calabria peloritani samples than in the middle to upper triassic betic rifian samples and suggest an increase of continental paleoweathering in the mediterranean region from the triassic to the jurassic in addition enrichment in sio 2 tio 2 al 2 o 3 k 2 o and incompatible elements in the calabria peloritani arc mudstones indicates sediment recycling effects that gradually increase from the triassic to jurassic time the hinterland paleoweathering and sediment recycling effects have been mathematically distinguished using principal component analysis pc1 is a measure of paleoweathering rate mainly due to humidity positive values against aridity negative values whereas pc2 corresponds to the extent of sediment recycling the results strongly indicate that humidity had increased from the triassic to the jurassic and that the depositional environments in calabria peloritani arc were probably more suitable for sediment recycling these seasonal climate alternations corresponding to an increase in paleoclimatic humidity that favored paleoweathering conditions and recycling processes these results are also confirmed by the mineralogical data which show a higher abundance of kaolinite typical of warm humid conditions in the calabria peloritani mudstones than in those of the betic cordillera and the rif furthermore the comparison among geochemical weathering index values of the studied samples and of recent soils from different climatic zones likely suggests a tropical rainforest climate in the studied area during the triassic to the lowermost jurassic

clay mineral formation and transformation in rocks and soils three mechanisms for clay mineral formation inheritance neoformation and transformation operating in three geological environments weathering sedimentary and diagenetic hydrothermal yield nine possibilities for the origin of clay minerals in nature several of these possibilities are discussed in terms of the rock cycle the mineralogy of clays neoformed in the weathering environment is a function of solution chemistry with the most dilute solutions favouring formation of the least soluble clays after erosion and transportation these clays may be deposited on the ocean floor in a lateral sequence that depends on floccule size clays undergo little reaction in the ocean except for ion exchange and the neoformation of smectite therefore most clays found on the ocean floor are inherited from adjacent continents upon burial and heating however dioctahedral smectite reacts in the diagenetic environment to yield mixed layer illite smectite and finally illite with uplift and weathering the cycle begins again

sicily s fold thrust belt and slab roll back the si ri pro seismic crustal transect sicily is a thick orogenic wedge formed by 1 the foreland african and its sicilian orogen and 2 the thick skinned calabrian peloritani wedge the crust under central sicily from the tyrrhenian margin to the coastline of the sicily channel has been investigated by the multidisciplinary si ri pro research project the project dealt with the nature and thickness of the crust and depth and geometry of the moho which is essential in formulating subduction models and improving the knowledge of african and tyrrhenian european lithospheres the results resolve features such as 1 the main orogenic wedge 2 the very steep nw se trending regional monocline suggesting inflection of the foreland crust 3 the deep caltanissetta synform imaged for the first time to about 25 km and 4 the top of the crystalline basement and the inferred crust mantle boundary the si ri pro transect confirmed that the nnw dipping autochthonous iblean platform of se sicily and its basement extends all the way into central sicily further nw towards the nnw end of the transect a large uplift involves the iblean platform and its underlying basement the associated gravity anomaly is interpreted as the southern wedge edge of the tyrrhenian mantle that splits the subducting iblean pelagian african continental slab from an overlying synformal stack of allochthonous thrust sheets supplementary materials additional data are available at www geolsoc org uk sup18594

a distant magmatic source for cretaceous karst bauxites of southern apennines italy revealed through shrimp zircon age dating karst bauxites occur at a late cretaceous hiatus on a bahamiantype platform in southern apennines italy in contrast to the well defined stratigraphic context their origin remains controversial detrital zircon grains preserve textures and th u ratios consistent with crystallization from a melt occasionally around older cores u pb isotopic data collected using shrimp ii record several age populations the youngest 90 ma falls into the age interval of bauxite formation as defined by stratigraphic criteria the zircons must therefore be derived from a contemporary cretaceous volcanic source the older zircons may be interpreted as xenocrysts associated with the cretaceous magmas or derived from different sources because the bauxite occurs on a isolated carbonate platform the grains must come from far away sources most probably transported by wind the age palaeogeography and inferred cretaceous wind pattern are consistent with a prevailing origin from the dinaric and carpatho balkan orogenic belts with its cretaceous bimodal volcanism

carbon isotope stratigraphy of early cretaceous urgonian shoal water deposits diachronous changes in carbonate platform production in the north western tethys abstract carbonate platforms are highly sensitive ecological systems that typically show rapid and characteristic response modes to environmental and climatic changes acting both on a regional scale and global scale a widely accepted hypothesis proposes that the late barremian stepwise establishment of the urgonian carbonate platform on the northern tethyan shelf was related to a gradual change from predominantly humid towards more arid greenhouse conditions this climate change resulted in the reorganisation of the carbonate platform ecosystem from heterozoan towards photozoan dominated assemblages and a decrease of organic matter burial in tethyan and boreal basins in order to decipher the palaeoenvironmental and climatic boundary conditions of these major changes in neritic and pelagic settings a precise chronostratigraphy of urgonian carbonate platform evolution is needed here we provide an integrated stratigraphic framework of lower barremian to lower aptian urgonian carbonate platform sections cluses forclaz located at the northern rim of the tethys subalpine chains ese france with special focus on sedimentological analyses and high resolution carbon isotope stratigraphy a characteristic barremian aptian carbon isotope pattern permits precise platform to basin correlation with cyclostratigraphic and ammonite dated pelagic and hemipelagic tethyan sections in the vocontian trough angles combe lambert glaise and umbria marche basin gorgo a cerbara similar to helvetic shoal water settings the carbonate platform in the subalpine chains experienced a gradual transition from heterozoan to photozoan dominated ecosystems this biogenic pattern points to a gradual change of the carbonate platform after the so called early barremian crisis towards an oligotrophic rimmed platform system urgonian limestone formation according to the chronostratigraphy of urgonian carbonate platform evolution in the subalpine chains established here the installation of a photozoan dominated rudist rich platform ecosystem referred to as urgonian limestones sensu stricto occurred at the early late barremian transition the onset of changes in the carbonate production mode heterozoan versus mixed heterozoan photozoan versus photozoan clearly predates the onset of similar lithological changes in the helvetic realm by about 1 0 to 1 2 myr the established chronostratigraphic framework points to a link between the change towards photozoan dominated limestones and fading palaeoenvironmental perturbations related to the mid barremian event which is associated with major faunal turnovers and the onset of cyclic black shale deposition in the central tethyan realm judging from palaeoenvironmental proxies including kaolinite phosphorus and black marl limestone ratios oscillating predominantly humid and relatively arid greenhouse conditions modulated the observed pattern in urgonian carbonate platform production mode and the varying frequencies of black shale deposits in the tethyan and boreal realms transient blooms of the orbitolinid foraminifera palorbitolina lenticularis at the onset of a marked upper barremian positive carbon isotope shift are interpreted to reflect increasing nutrient influx most probably related to accelerated hydrological cycling and or sea level rise these strata do not represent an over regional correlatable lithostratigraphic unit but likely an expression of progressive northern tethyan environmental and oceanographic change possibly related to ontong java large igneous province volcanism in the prelude of oceanic anoxic event 1a oae

origin of deep water fine grained sediments as revealed from the lower cretaceous rifting basin sequence in the lingshan island yellow sea eastern china abstract understanding the sediment dynamics responsible for the deposition of fine grained sediments is essential for studying fine grained sediment origin and its distribution which is of a great significance for unconventional oil and gas exploration and development fine grained sediments from a lower cretaceous rift basin sequence in the lingshan island the middle of the dengta section in the lingshandao formation were studied on the basis of detailed outcrop investigation thin section observation and laboratory measurements seven types of lithofacies and three lithofacies associations were identified in the fine grained sediment sequence the sediment dynamics were deduced from a comprehensive examination and interpretcation of the sedimentary structures and lithofacies associations the fine grained sediments in the research area belong to a silt dominated subclass which is composed mainly of thin bedded siltstones with normal grading and mudstones with horizontal lamination suspension settling is responsible for the development of horizontal lamination in some mudstone the bouma like lithofacies associations are developed by downslope fine grained turbidity currents the hybrid event bed like lithofacies associations are formed by hybrid flow while turbidity currents transformed to muddy debris flows downslope the interbedded thin sandstone and mudstone banded lithofacies associations may be resulted from a downslope transitional flow between a turbidity current and a muddy debris flow the vertical facies stacking patterns of the fine grained sediment sequence indicatec that the fine grained gravity flow may have been evolved from a transitional flow to a debris flow then to a low density turbidity flow and finally to a hybrid flow lithofacies associations deposited by hybrid flow and transitional flow are potential sweet spots for unconventional oil and gas exploration in such fine grained sediment formation