The objectives of this overview are to establish fundamental concepts of sequence stratigraphy and to define terminology critical for the communication of these concepts. Many of these concepts have already been presented in earlier articles on seismic stratigraphy (Vail and others, 1977). In the years following, driven by additional documentation and interaction with co-workers, our ideas have evolved beyond those presented earlier, making another presentation desirable. The following nine papers reflect current thinking about the concepts of sequence stratigraphy and their applications to outcrops, well logs, and seismic sections. Three papers (Jervey, Posamentier and Vail, and Posamentier and others) present conceptual models describing the relationships between stratal patterns and rates of eustatic change and subsidence. A fourth paper (Sarg) describes the application of sequence stratigraphy to the interpretation of carbonate rocks, documenting with outcrop, well-log, and seismic examples most aspects of the conceptual models. Greenlee and Moore relate regional sequence distribution, derived from seismic data, to a coastal-onlap curve. The last four papers (Haq and others; Loutit and others; Baum and Vail; and Donovan and others) describe application of sequence-stratigraphic concepts to chronostratigraphy and biostratigraphy.

Submarine gravity flows are a key process for transporting large volumes of sediment from the continents to the deep sea. The location, volume, and character of the sediment bypassed by these flows dictates the areal extent and thickness of the associated deposits. Despite its importance, sediment bypass is poorly understood in terms of flow processes and the
associated stratigraphic expression. We first examine the relationships between the physical parameters that govern bypass in flows, before assessing the variable stratigraphic expression of bypass from modern seafloor, outcrop, and subsurface datasets. Theoretical and numerical approaches distinguish grain size, slope, flow size, and sediment concentration as parameters that exert major controls on flow bypass. From field data, a suite of criteria are established to recognize bypass in the geological record. We identify four bypass-dominated zones, each of which is associated with a set of diagnostic criteria: slope-channel bypass, slope-bypass from mass wasting events, base-of-slope bypass, and basin-floor bypass. As the expression of bypass varies spatially and is dependent on the scale of observation, a range of scale-dependent criteria are required for robust interpretation
of these zones in the field or subsurface. This synthesis of deep-water sediment bypass highlights the challenge in quantitatively
linking process with product. The establishment of criteria to recognize sediment bypass, qualitatively linked with flow
processes, is an important step towards improving our understanding of submarine flow dynamics and resultant stratigraphic architecture.

Exploration efforts in the Bulgarian Black Sea were largely restricted to the shelf to date and therefore the deepwater area remains untested in spite of the significant exploration potential.
The presence of a deepwater petroleum system is proved by several DHIs, such as gas chimneys and gas-related velocity sags evidenced by high quality 3D seismic data.
At least six different deepwater play types have been identified by OMV in the Bulgarian offshore. Most of these plays are related to the  prominent syn-rift Polshkov High either in intra-Tertiary structural closures in the compactional anticline above, or within the Mesozoic syn-rift or early post-rift sequence. The deepest exploration target is the Polshkov High itself, where the trap is defined by several fault blocks in which the assumed Jurassic and/or Lower Cretaceous carbonate platform sequence may have a reservoir facies suitable for deepwater gas production. The target of this play is analogous to the ones targeted over the mid-Black Sea High (Andrusov Ridge) offshore Turkey or over the Tetyaev High offshore Ukraine.

Sicily is a Mediterranean island-region, whose economy is based especially on tourism and also connected with beaches. Unfortunately, in the last fifty years about 2.5 km 2 of beach were lost due to erosion, causing damages worth approximately 5 billion Euros. At the moment about 300 km of the 1600 km of coast present erosion problems, 1/3 of which is threatening the economic and important historical assets as well as Sicilian cultural heritage. The Sicilian region decided to solve the issue, avoiding passive protection systems only used for urgent action, but instead adopting a Coastal Management Plan (CMP) aimed essentially at the use of soft protection systems, e.g. beach replenishment. In order to put into practice this type of intervention, thanks to a synergic collaboration with the CMP, a Borrow Deposits Plan (BDP) was drawn up, identifying three possible sources of materials: fluvial material, harbour dredging and submerged deposits. The detected deposits can be estimated in about 5 million m 3 of fluvial deposits useful for the pebbly beaches of the northeastern sectors, while the ones coming from harbour dredging, about 3 million m 3 , can be used only for local intervention. Submerged deposits located along the northwestern coast of the island have a strategic importance. They are situated at a depth of 100 m and are about 120 million m 3 , with excellent granulometric (fine and medium sands) and compositional features (quartz > 50%). It is clear that in order to better exploit the resources and above all reduce costs, it will be necessary to correctly manage the intervention, that will have to be carried out with the appropriate timing.

Relatively fresh exposures of the Semantan Formation along the East-Coast Highway (Lebuhraya Pantai Timur-Fasa 1) between Karak and Kuantan, central Peninsular Malaysia, have given new insights into the sedimentary processes in the Triassic flysch basin that once separated west and east Malaya. An eastward change from distal to proximal facies between Karak and Maran indicates a west-facing, active continental shelf to slope sedimentation. Outcrops between Karak and Temerloh, east of the Late Triassic-Early Jurassic Bentong-Raub collisional suture, are generally characterized by "classical" flysch-like, thinly-bedded sandstone-mudstone facies. Further east of Temerloh towards Maran, and nearer to the paleo-shelf and slope, more sandy and thick-bedded turbidite facies occur. A proximal deep-marine facies association in the Semantan Formation is exposed at the Chenor Junction (Exit 821), kilometre 139 along the highway. South-and north-facing cuts on either sides of the highway reveal large gravity-slide blocks (megaclasts), slumps, debris flow deposits, and associated syn-sedimentary thrust faults and glide surfaces. These features are strongly indicative of large-scale submarine mass-transport processes on the palaeo-slope of the Triassic active margin. The Chenor mass-transport complex is made up of zones of incoherent slump deposits intercalated with well-bedded turbidite/debrite facies. In the lower part of the succession, there are megaclasts of sandstone-mudstone facies, measuring several metres in size, encased in a plastically deformed silty matrix. The megaclasts are highly deformed internally by numerous meso-scale normal faults, probably due to gravitationally-induced extension. Along with other smaller sandstone blocks, these megaclasts are interpreted as slide blocks due to slope failure up-dip. There are other gravity-induced structural features such as rotational slumps, glide surfaces, thrust faults and associated soft-sediment folds. The slump folds and thrusts show vergence to the west, as opposed to the generally eastward tectonic vergence. A few of the well-stratified units show strongly inclined stratal surfaces which may be attributed to lateral accretion of turbidite fan lobes. Several sets of these inclined surfaces are bounded by erosional surfaces which could have resulted from different episodes of turbidity flow. The association of incoherent mass-flow units with the more well-stratified deposits reflects the close spatial and temporal relationship between submarine mass-transport events and turbidity flows on the Triassic active slope and basin plain.

Abstract We present a critical appraisal of the role of subducted, medium (10–1000 km2) to giant (≥1000 km2) and heterogeneous, mud-rich mass transport deposits (MTDs) in seismic behavior and mechanisms of shallow earthquakes along subduction plate interfaces (or subduction channels) at convergent margins. Our observations from exhumed ancient subduction complexes around the world show that incorporation of mud-rich MTDs with a “chaotic” internal fabric (i.e., sedimentary melanges or olistostromes) into subduction zones strongly modifies the structural architecture of a subduction plate interface and the physical properties of subducted material. The size and distribution of subducted MTDs with respect to the thickness of a subduction plate interface are critical factors influencing seismic behavior at convergent margins. Heterogeneous fabric and compositions of subducted MTDs may diminish the effectiveness of seismic ruptures considerably through the redistribution of overpressured fluids and accumulated strain. This phenomenon possibly favors the slow end-member of the spectrum of fault slip behavior (e.g., Slow Slip Events, Very Low Frequency Earthquakes, Non-Volcanic Tremors, creeping) compared to regular earthquakes, particularly in the shallow parts (T

43 Olistostromes (sedimentary mélanges) represent the products of ancient submarine mass 44 transport processes. We present a comparative analysis of the occurrences and internal structures of 45 these sedimentary mélanges at a global scale with a focus on the Circum-Mediterranean, Appalachian 46 and Circum-Pacific regions, and discuss their formation and time-progressive evolution in different 47 tectonic settings. Lithological compositions, stratigraphy, and structural features of olistostromes 48 reflect the operation of an entire spectrum of mass transport processes during their development 49 through multi-stage deformation phases. The general physiography and tectonic setting of their 50 depocenters, the nature, scale and rate of downslope transformation mechanisms, and global climatic 51 events are the main factors controlling the internal structure and stratigraphy of olistostromes. Based 52 on the tectonic settings of their formation olistostromes are classified as: (i) passive margin, (ii) 53 convergent margin and subduction-accretion, and (iii) collisional and intra-collisional types. Systematic 54 repetitions of these different olistostrome types in different orogenic belts provide excellent markers for 55 the timing of various tectonic events during the Wilson cycle evolution of ocean basins. Olistostromes 56 are best preserved in paleo active margins, covering vast areas of thousands of km 2 , where they 57 underwent significant downslope translation, up to hundreds of kilometers. Incorporation of 58 olistostromes into subduction-accretion complexes and orogenic belts takes place during discrete 59 episodes of tectonic events, and their primary (sedimentary) fabric may be commonly reworked and 60 overprinted by subsequent phases of tectonic and metamorphic events. We apply the basic 61 nomenclature of structural geology, sedimentology and basin analysis in studying the internal 62 structure, lithological makeup, and mechanisms of formation and extraordinary downslope mobility of 63 olistostromes. 64 65

In the back-arc basin of southern Peru, the bulk of the mid-Cretaceous carbonate platform collapsed near the Turonian–Coniacian boundary (~ 90–89 Ma), due to slope creation and resulting oversteepening. The resulting mass-wasting deposits, namely the Ayabacas Formation, consist of a megabreccia which is organised from NE to SW in relation with two major fault systems. Facies of sediment reworking (such as brecciation, liquification, sedimentary dykes and soft-sediment deformation) are described and four types of resedimentation facies are define.In the northeastern part of the study area, deposits mainly consist of a mixture of very heterometric clasts and blocks (millimetric to kilometric in size), mainly carbonate but also sandy–marly in nature, floating in sandy–marly matrix that exhibits features of liquification (sedimentary dykes and flows) and plastic deformation. Here, resedimentation facies are characterized by deformations and a brecciated facies at each observation scale (from aerial photographs to thin sections) and are therefore defined as fractal or multi-scale breccias. Some clasts and large amounts of the matrix were derived from the underlying clay-rich sandstones of the Murco Formation. These materials were prone to liquification and plastic deformation, allowing them to act as a sliding sole that facilitated the slides and the downslope movement of large limestone rafts.In the southwestern part of the study area, only limestone breccias are observed, in alternation with well-stratified levels. The sliding sole of plastically deformable siliciclastic sediments that previously acted as a lubricating layer was not present here, as materials were more deeply buried.Variations in the degree of sediment lithification from northeast to southwest are inferred to have existed before the collapse and also within the sedimentary succession in the northeastern part. In particular, limestones were well-cemented at the base of the carbonate succession and formed a cap that prevented water to escape from the underlying siliciclastic materials. Such a succession allowed the formation of limestone clasts and of a slide sole constituted by water-saturated siliciclastic materials.In the southern part of the study area, the slide surface was located within the Murco Formation in the upper part of the collapse and just above the Murco Formation downslope. The collapse was frontally confined as it was blocked downslope by a topographic high that folded the whole limestone succession. In the northern part of the study area, the slide surface was also within the Murco Formation in the upper part, but occurs within the limestone succession downslope, due to higher subsidence that buried the sediments more deeply. The compressional structures affecting the limestone succession in the south are not observed there, suggesting that the toe of the collapse was not blocked here.

In diapir flanks, unconformity-bounded sedimentary packages associated with gravity-driven deposits, controlled by the ratio between the rates of sediment accumulation and diapir growth can be interpreted in the context of halokinetic sequences. The Bakio Breccias Formation (Basque Country, Spain) corresponds to redeposited carbonate deposit that developed in response to the Bakio diapir growth during the Middle Albian. These deposits provide on of the rare documented example of carbonate dominated halokinetic sequences. The Bakio Breccias Formation consists of an alternation of clast- and matrix-supported breccias, calcirudite, calcarenite and marl, deposited along the flanks of the diapir. The description and the analysis of the Bakio Breccias Formation lead to a new model for carbonate-dominated halokinetic sequences. These sequences differ from their siliciclastic counterpart because sediment accumulation rate is controlled by carbonate platform growth on the topographic relief top of the diapirs, while sediments are preferentially deposited in the mini-basins adjacent of the diapirs, in siliciclastic settings. During transgressive system tract, carbonate platform are able to keep up with the sea level rise and to aggrade on top of the diapirs, forming thick and resistant roof, which is assumed to limit the diapir growth and thus to favour the development of halokinetic sequences with low angle unconformities (wedge halokinetic sequences). During late highstand system tract deposition (and lowstand system tract if present), platform progradation results in high sediment accumulation in the adjacent depocenters, loading the autochthonous salt layer and promote diapir growth and creation of topographic relief. In addition, if the diapir roof reaches emersion, karstification of the carbonate platform top may also favour roof destruction and diapir growth. Depending on the thickness of the roof developed previously and the amplitude of the sea level fall, the halokinetic sequences with the emersion and the karstification of the carbonate platform may display high angle unconformities (hook halokinetic sequences). Furthermore, gravity-driven deposits are assumed to be more common in carbonate-dominated halokinetic sequences, compared to their siliciclastic counterparts, since carbonate platform aggradation creates steep slopes on the diapir margins, leading to the partial collapse of the margin, even when limited diapir growth occurs. The carbonate-dominated halokinetic sequence model proposed here is an important tool for the prediction of potential reservoir distribution, seal and hydrocarbon migration in flanks of salt diapirs where carbonate platform developed.

This is a post-print (peer-reviewed, corrected) version of Omosanya, K.O., Harishidayat, D., 2019. Seismic geomorphology of Cenozoic slope deposits and deltaic clinoforms in the Great South Basin (GSB) offshore New Zealand. Geo-Marine Letters 39, 77-99.

Several submarine landslides were identified on the Storfjorden Trough Mouth Fan (TMF) to the southwest of the Svalbard Islands during two recent research cruises carried out within the International Polar Year (IPY). The Spanish SVAIS and the Italian EGLACOM cruises, respectively in the summer of 2007 and of 2008, both contributed to IPY Activity 367 NICE-STREAM (Neogene ice streams and sedimentary processes on high-latitde continental margins) aimed at understanding erosion and depositional systems associated with ice streams. Thin-skinned modern landslides, visible on both swath bathymetry data and on sub-bottom and multichannel seimic reflection profiles, are composed by a long, sharp-edged, straight channel developed downslope of the head scars, which lie on the upper-middle continental slope. Giant paleo landslides, detected only on multichannel seimic reflection profiles, are characterized by thick (up to over 200 ms thick) chaotic deposits on the lower part of the continental slope. Both modern and paleo landslides are focused in the southern part of the Storfjorden TMF, towards the northern border of the Bear Island TMF. The area is peculiar because of the presence of a large deep-sea channel system, the INBIS channel system (Vorren et al., 1998)). Channel systems in fact are rare on the Norwegian margin and confined to the INBIS and Lofoten Basin channels. Also peculiar of this area is the presence on continental shelf of a sharp, narrow cross-shelf trough, the Kveithola Trough, which shows glacial growes and boundles produced by fast-flowing grounded ice. This evidence suggests to us that the abundance of basal meltwater beneath the ice, a key factor for the lubrication and motion of ice-streams, is also crucial for the inception of mass-movements along the INBIS Channel and for the genesis of the landslides indentified in this sector of the margin. References: Vorren, T.O., Laberg, J.S., Blaumme, F., Dowdeswell, J.A., Kenyon, N.H., Mienert, J., Rumohr, J., Werner, F., 1998. The Norwegian-Greenland Sea continental margins: morphology and Late Quaternary sedimentary processes and environment. Quat. Sci. Rev. 17, 273-302.

We report here mass transport-related disruption processes and their artifacts within sedimentary mélanges. The case studies include the early Oligocene wedge-top mass transport deposits in the northern Apennines (Italy) and the Eocene foredeep carbonate megabreccias from the south-central Pyrenees (Spain). These “chaotic” units commonly share a block-in-matrix fabric expressed by variously deformed slide blocks of different size, lithology, age and

Abstract Intense stratal disruption and lithological mixing is generated during sedimentary transport events, highlighting that gravitational processes are efficient mechanisms in the production of different types of mass transport deposits (MTDs) with internal block-in-matrix arrangement. Extra- and intrabasinal MTDs exhumed in orogenic belts worldwide, identified as olistostromes and sedimentary melanges in the first case, record the final products of the downslope evolution of landslide masses, from slope failures to gravity flows. Specific sedimentary fingerprints are commonly preserved within such “chaotic” rock units, even though usually reworked by polyphased tectonics and associated metamorphism. One of the main conceptual issues in this framework is the occurrence/incorporation of “exotic” clasts and blocks (baseline criterion for melange definition). We here provide an outline of the primary, multi-scale structures identified in key case studies from the northern Apennines of Italy and the northwestern Dinarides in Slovenia. We focus on mechanisms responsible for the entrainment of intra- (native) and extra- (exotic) basinal material and its progressive deformation. Important information, such as the kinematics of processes and internal strain partitioning, can be reconstructed from the study of such features, providing fundamental paleographic and paleo-physiographic constraints, as well as consolidating the basis for a possible updated reappraisal of some classic melanges.