The stratigraphic architecture of Early Jurassic strata exposed along a >10 km long transect in the Chachil Graben, an exhumed marine rift depocentre in the Neuquén Basin (Argentina), provides insights into the sedimentological and stratigraphic expression of the syn‐rift to post‐rift transition. A change from syn‐rift intrabasinal carbonate to post‐rift extrabasinal siliciclastic sedimentation is recorded, as well as variations in sediment supply and dispersal patterns across rift‐related topography. The late syn‐rift was marked by a transgression and development of a shallow‐marine carbonate system, including carbonate platform deposits perched on fault‐block highs and periplatform deposits accumulated in fault‐block lows, which overlies continental volcano‐sedimentary syn‐rift deposits. Differential subsidence and basin deepening induced retrogradation of the carbonate system, which was progressively drowned and overlain by organic‐rich calcareous mudstone that draped across rift structures at the onset of the early post‐rift. The first extrabasinal siliciclastic influx led to progradation of an early post‐rift intraslope lobe complex into the graben, which is associated with kilometre‐scale clastic injectites. The depositional architecture, facies distribution and pinch‐out style of intraslope lobes record the effects of an inherited compaction hinge, which acted as an oblique counterslope to sediment gravity flows. The occurrence of combined‐flow bedforms, widespread erosion, and limited facies segregation across lobes bearing different hybrid event bed types, is in sharp contrast to sedimentological characteristics of existing intraslope lobe models. Documentation of the syn‐rift to post‐rift transition stratigraphy permitted identification of changes in thickness and facies resulting from the passive infill of inherited topography with early post‐rift differential compaction. This architecture contrasts markedly with those developed during syn‐rift normal faulting. Furthermore, the influence of local inherited topography on the development of early post‐rift lobes is key to improve subsurface prediction of sandstone distribution and quality during assessment of hydrocarbon reservoirs and carbon storage sites.

The reconstruction of regional long‐term patterns recorded in marine sedimentary successions of the Eastern Paratethys is important in understanding the role of Cenozoic climate change and orogenic activity on the depositional environment and sedimentation dynamics in Western Asia. In this study, the environmental conditions in the early to middle Miocene (Islam Dağ section) in eastern Azerbaijan are elucidated using petrographic–mineralogical relations, detrital indicators, weathering indices and δ13C and δ18O signatures of organic‐rich (total organic carbon: ca 3 to 6 wt. %) argillites. Sedimentary facies and chemical proxies (Na/K, K/Al, Si/Al, Ti/Al ratios, chemical index of alteration values) indicate arid conditions, reduced weathering rates in the hinterland and sediment deposition in an euhaline and poorly oxygenated deep‐water basin during the early Miocene, followed by a shift to humid conditions, higher weathering rates and an oxygenated water column in the mid‐early Miocene. Long‐term aridification and deposition of gypsiferous and calcareous argillites under generally more oxygenated, euhaline to polyhaline conditions in a lacustrine or restricted shelf setting until the middle Miocene is evidenced by gradual changes in element ratios and the chemical index of alteration. Discriminant function analysis suggests the Russian Platform, drained by the Palaeo‐Volga and Palaeo‐Don river systems, to be the source area for the siliciclastic input throughout the Miocene, although a minor contribution of volcanogenic detritus and mafic components from the Greater Caucasus is possible. The C–S–Fe associations and increasing Fe/Al ratios towards the middle Miocene support the concept of continuous influx of detrital Fe and total organic carbon. The formation of ferruginous smectite from alteration of volcanic ash layers could have affected the preservation of total organic carbon and therefore the sedimentary C and Fe budget in the Eastern Paratethys basins. Palaeo‐climatic reconstructions based on δ13C (−34·5 to +1·7‰ Vienna Pee Dee Belemnite) and δ18O (−34·7 to −4·8‰ Vienna Pee Dee Belemnite) records of authigenic carbonates should be made with great caution, as the pristine marine signatures may be affected by the oxidation of organic matter and meteoric diagenesis.

Abstract Salt marsh and mud flat sedimentation in the Wadden Sea and in similar depositional regions is usually dependent on the net import of fine-grained sediments from adjacent marine environments. This net import takes place as a result of several processes such as settling lag and scour lag. This paper utilizes a database comprising time series of tidal velocity and turbidity in the Grådyb tidal area of western Denmark as the basis of a simple conceptual model which describes the transport, deposition and resuspension of finegrained material in the area. The results demonstrate that: (a) grain sizes close to the sand/silt boundary are most sensitive to lag effects; (b) scour lag is much more important than settling lag; (c) raised temperatures enhance the net-lag effect for silt with increasing importance for finer grain sizes; (d) with increased suspended concentrations, the time it takes to resuspended the material deposited at slack water (the resuspension lag) is of increasing importance for the net-lag effect.

Abstract Sedimentological studies have recently been carried out in the Spiekeroog back-barrier area (southern North Sea coast of Germany) to explore the interrelationship between the surficial sediment distribution patterns, energy levels, and transport processes. The sediment distribution patterns show that the sediment generally becomes finer landwards (north-south), irrespective of the tidal channel orientations (east-west). a closer examination, however, shows two distinct patterns. The first pattern is a general landward-fining of the sediments within the inlet from about 1.0 phi (0.50 mm) in the inlet throat to about 3.5 phi (0.088 mm) on the landward reaches of the inlet. This pattern is a result of the decrease in current velocity from the inlet throat landwards. The second pattern, which is the most conspicuous on the mean grain-size map, shows a distinct shore-normal (north-south), landward sediment fining across the tidal flats from about 2.0 phi (0.25 mm) on the islands to 2.5–3.0 phi (0.25–0.125 mm) on the tidal flats to as fine as 3.5 phi (0.088 mm) along the dike (mainland coast). This shore-normal sediment fining has been found to be a result of the shore-normal energy gradient (flow velocity) associated with overbank flow from one channel to the next. The analysis of skewness evolution has been shown to be a powerful tool for the interpretation of transport pathways in a tidal environment. Skewness distribution patterns indicate that the inlet areas act as sources of sediment from which sediment is transported landwards during the flood tide and seawards during the ebb phase. In the whole area, however, the fine sediment fraction (population) whose energy niche is the landward margin of the backbarrier areas, and the coarse fraction characterizing the inlet throat areas, undergo a range of population mixing as well as progressive sorting of the individual populations. Progressive sorting appears to be dominant normal to the shore and across the tidal flats whereas mixing processes are more pronounced along the main channel of the tidal inlets.

The Early to Middle Eocene 170 m thick Sylhet Formation of Assam and Assam-Arakan Basin belongs to an overall fining-upward 2nd order transgressive systems tract (TST). It consists of a mixed siliciclastic-carbonate sequence and the overall facies architecture implies deposition in a tide affected marginal marine (deltaic) to inner shelf carbonate ramp with episodic clastic supply from western hinterland by isolated protorivers during regressive phases. High resolution sequence stratigraphic analysis based on core and electrolog data allows to subdivide the 2nd order TST into 3 systems tracts of 3rd order, (i) basal TST, represented by shale and limestone followed by (ii) a highstand systems tract (HST) incorporating sandstone, limestone and shale, and (iii) a TST at the top. The HST can be further subdivided into 4th order parasequencesets separated by marine flooding surfaces. The isopach and isolith maps of 4th order units as well as the conceptualized depositional model reveal a minimal sand supply at beginning of 3rd order HST and a significant increase in fluvial sand thereafter, resulting basinward progradation of facies and paleo shoreline due to a punctuated slow rise of relative sea-level that leads to constructive delta building until the end of 3rd order HST. The topmost 3rd order TST marks a landward retreat of facies due to paucity of sand supply and rise in relative sealevel. As basin margin areas are more prone to periodic exposures related with lower order sea-level fluctuations, the secondary porosity development within sandstone and limestone has resulted due to percolation of meteoric water leading to significant dissolution of early formed calcite cement. Such phenomena are clearly evident by petrographic and SEM data and are helpful in finding the locales of better reservoir facies. Sylhet Formation is characterized by abundant glauconitic horizons at selected stratigraphic levels that represent intervals of marine flooding events (MFE) of 3rd and 4th order sea-level change. The glauconites associated with MFE result in a condensed section with minimum sediment supply. The glauconitic horizons provide a key parameter to build the sequence stratigraphic architecture of the Eocene sequence. The depositional model and diagenetic events of such mixed siliciclastic-carbonate system are correlated, which helps explain the extent of shortterm transgressive-regressive cycles, improving elucidation of hydrocarbon-bearing sand units for future exploration. Introduction High-resolution sequence stratigraphy (HRSS) deals with a scale of observation that typically falls below the resolution of seismic exploration methods, commonly referred to as lower order (4th-5th order) cycles. It is currently one of the potential areas of stratigraphic research, with a wide range of applications, from reservoir geology to tectonism and climate change (e.g., Galloway, 1989; Zecchin, 2005, 2007; Cantalamessa et al., 2007; Catuneanu et al., 2009; Zecchin et al., 2009, 2010, 2011; Csato et al., 2014). One of the key objectives of such analysis is to identify reservoir and source facies that are essential parts of a petroleum system. This article is focused on the Early to Middle Eocene Sylhet Formation in the North and South Assam Shelf (NAS and SAS) blocks of the Assam and Assam-Arakan Basin (A&AAB, Figure 1). So far, the dominantly carbonate Sylhet Formation has been interpreted as a carbonate ramp depositional system with development of sandstone near its top (Singh et al., 2011). Paleogeographic reconstruction is based on faunal and floral evidence and lithological associations suggest widespread transgression during Early Eocene to Oligocene time, which was associated with accumulation of a 2nd order transgressive systems tract (TST) (Singh et al., 2011). However, such a TST is characterized by several small fining-upward and coarsening-upward cycles, within an overall fining-upward trend. Thus, identification of these high frequ

Submarine canyons are morphological incisions into continental margins that act as major conduits of sediment from shallow- to deep-sea regions. However, the exact mechanisms involved in sediment transfer within submarine canyons are still a subject of investigation. Several studies have provided direct information about contemporary sedimentary processes in submarine canyons that suggests different modes of transport and various triggering mechanisms. Storm-induced turbidity currents and enhanced off-shelf advection, hyperpycnal flows and failures of recently deposited fluvial sediments, dense shelf-water cascading, canyon-flank failures, and trawling-induced resuspension largely dominate present-day sediment transfer through canyons. Additionally, internal waves periodically resuspend ephemeral deposits within canyons and contribute to dispersing particles or retaining and accumulating them in specific regions. These transport processes commonly deposit sediments in the upper- and middle-canyon reaches for decades or centuries before being completely or partially flushed farther down-canyon by large sediment failures.