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Lateral facies heterogeneity and carbonate production perturbation within peri-Tethyan platforms were widespread phenomena during the Early Jurassic. These variations were either controlled by local factors affecting small areas or by processes prevailing on a global scale. Three geological sections are investigated in Lower Jurassic outcrops in the Traras Mountains, northwest Algeria, from synrift-settings to disentangle the influence of local and global factors. The detailed sedimentological study reveals 11 facies types, grouped into four facies associations ranging from alluvial fan to outer ramp setting. Whereas thickness variation and lateral facies distribution are mainly controlled on a regional scale by synsedimentary tectonics, resulting from the spreading of the Tethys, the irregular topography inherited from the palaeo-alluvial fan topography of the underlying Beni Menir Formation seems to be the main control on a local scale. This irregular topography which coexisted in very close proximity to the studied carbonate deposits provided a significant amount of siliciclastic input, partially disturbing carbonate production. The local erosion of this detrital material during the initial early Pliensbachian transgression, combined with other local factors such as a low rate of accommodation space renewal and high-energy conditions, resulted in the absence of the otherwise prevalent Lithiotis fauna in the studied sector. Siliciclastic input perturbating carbonate production during the late Pliensbachian to early Toarcian could instead have been induced by a global warming event that increased continental weathering at the global scale during the Pl/To boundary or T-OAE associated with storm intensification. Alternatively, in view of the lack of solid biostratigraphic attribution, high terrigenous input could also have been induced from a cooling event leading to a sea-level fall during the latest Pliensbachian (Emaciatum Zone) and/or the lowermost Toarcian (latest Tenuicostatum Zone). In addition to tectonics, this eustatic sea-level fall could also explain the absence of shallow carbonate production in the Traras Mountains during these periods. In the future, a multidisciplinary basin-scale approach may resolve these uncertainties related to the lack of biostratigraphic dating, thus helping to identify the key factor influencing the perturbation of carbonate production. [ABSTRACT FROM AUTHOR]

The flat-topped Slivnista carbonate platform was subaerially exposed during the earliest Valanginian and intense karstification occurred until the latest Valanginian producing various breccia types. The platform demise was caused by a relative sea-level fall but a drastic paleoenvironmental change around the Berriasian/Valanginian boundary also contributed to the shutdown of the carbonate factory. This is revealed by a rapid change from photozoan through heterozoan and then to non-skeletal mode of carbonate production. A similar biological crisis is known from other carbonate platforms across the Western Tethys and was probably associated with climate cooling, humidification and increase of marine trophic levels. The late development of the Slivnitsa platform was affected by synsedimentary extensional tectonics that led to differential uplift and emergence. This tectonic activity was most likely related to the Neo-Cimmerian (Late Cimmerian) phase. [ABSTRACT FROM AUTHOR]

This paper studies ten Subbetic (Betic External Zones) stratigraphic sections spanning the Pliensbachian–early Toarcian time interval. Eight lithofacies were distinguished: crinoidal limestones, peloidal limestones, breccias, cherty limestones, nodular limestones, hardground surfaces and condensed levels, marls and marly limestone alternance, and dark marls. The biostratigraphy matches data from ammonite and calcareous nannofossil zonations. In addition, we analyzed C and O isotopes from bulk samples from three of the studied sections in which the lower Toarcian sedimentation crops out. The demise of the Lower Jurassic shallow platform developed in the South Iberian Paleomargin was a complex process driven by rifting, which led to tilted blocks giving way to different sedimentary environments. The tectonic stages occurred in the Sinemurian–Pliensbachian transition (R1), toward the lower part of the Ibex Zone (FO of the Biscutum grande, R2), in the Ibex–Davoei zones boundary (FO of Lotharingius barozii, R3), in the lower–upper Pliensbachian (R4), and in the lower boundary of the NJT4d nannofossil Subzone (R5) (Lavinianum Zone, upper Pliensbachian). After this last phase, sedimentation became pelagic in origin throughout the basin, represented by the sections studied. However, the isotope data show no clear record of the different C-isotopic events, though the Davoei–Margaritatus Event, the late Pliensbachian Event, and the Pliensbachian–Toarcian Boundary Event (PTBE) could be cautiously identified. These geochemical features are explained by the convergence of marine currents from Panthalassa (through the Hispanic Corridor) and Tethys. [ABSTRACT FROM AUTHOR]

In the central Southern Alps (N Italy) some well-preserved Permian extensional structures, that exceptionally escaped the Alpine deformation, have been recently identified. Their analysis offers important insights for the interpretation of the post-Variscan tectonics affecting the Southern Alps during the Permian. We describe here a previously unknown fault system related to the development of the Early Permian Orobic Basin, where large exposures of the Variscan basement preserve their original tectonic contacts with the overlying Lower Permian cover. The fault system consists of Low-Angle Normal Faults (LANFs) accompanied by High-Angle Normal faults (HANFs), these last entirely developed within the volcanic, volcaniclastic and terrigenous deposits. The studied structures occurring in the upper part of the Gerola Valley, share several features with Early Permian normal faults already recognized in other areas of the central Southern Alps. The low-angle normal fault planes are characterized by a continuous layer of coarse-grained fault breccias, locally impregnated by tourmalinites. The fault rocks have been invariably observed along the fault surface at the basement-cover contact all across the study area. This newly identified fault system with its characteristic combination of low- and high-angle normal faults suggests a tectonic regime characterized by pure extension in the central Southern Alps, rather than by a transtensional regime during the Early Permian. The provided data give new insights into the Early Permian geodynamic scenario, which is discussed in light of the transition from the Pangea B to the Pangea A configuration. [ABSTRACT FROM AUTHOR]

The identification of the factors triggering continental environmental changes at the Permian–Triassic transition is of general interest as they allow a better understanding of the most controversial mass extinction of the Phanerozoic. This study investigates the environmental response to external forcings on continental successions at the south‐east‐margin of the Central European Basin System in Germany. Studies from this area are scarce, and its evolution is poorly understood. This work integrates high‐resolution core‐logging and quantitative sedimentary petrography of Middle Permian–Early Triassic successions recovered from the wells Obernsees‐1 and Lindau‐1. The sedimentological investigation reveals major vertical variations in the depositional settings marked by changes in grain‐size trends and facies associations: (i) the progradation of mass flow/fluvial fans over sandflat environments denotes the Guadalupian–Lopingian; (ii) sabkha to shallow‐marine conditions occur during the uppermost Permian; (iii) the onset of braided fluvial sequences marks the Permian–Triassic boundary; (iv) changes in fluvial style, reflecting increased river sinuosity, and aeolian deposition characterize the remaining Triassic. Environmental changes are accentuated by variations in sediment composition. Proximal deposits (for example, alluvial fan) are lithic arkoses, while more distal associations reveal arkosic composition. Detrital modes point to: (i) a high‐grade metamorphic source feeding the drainage of Lindau‐1 (metamorphic index, MI 441–500); and (ii) a mixed low‐grade and high‐grade metamorphic source (MI 277–395) feeding the Permian of Obernsees‐1, passing upward to high‐grade metamorphic (MI 441–500) and subordinate granitoid sources. Compositional signatures and environmental changes suggest distinct drainage evolutions regulated by upstream climate and tectonic controls. The higher plutonic clast content coeval to the onset of fluvial sedimentation and coarse‐grained influxes reflects local tectonic perturbations attributed to the Early Triassic reactivation of Variscan faults. The evidence of perennial fluvial systems during the lowermost Triassic reflects wetter climate conditions in the upstream catchment area, which contradicts the common view of increased aridity at the Permian–Triassic boundary. [ABSTRACT FROM AUTHOR]

The Garedu Red Bed Formation (GRBF) of the northern Tabas Block (Central-East Iranian Microcontinent, CEIM) is a lithologically variable, up to 500-m-thick, predominantly continental unit. It rests gradually or unconformably on marine limestones of the Esfandiar Subgroup (Callovian–Oxfordian) and is assigned to the Kimmeridgian–Tithonian. In the lower part, it consists of pebble- to boulder-sized conglomerates/breccias composed of limestone clasts intercalated with calcareous sandstones, litho-/bioclastic rudstones and lacustrine carbonates. Up-section, sharp-based pebbly sandstones and red silt-/fine-grained sandstones of braided river origin predominate. Palaeocurrent data suggest a principal sediment transport from west to east and a lateral interfingering of the GRBF with marine greenish marls of the Korond Formation at the eastern margin of the Tabas Block. Westwards, the GRBF grades into the playa deposits of the Magu Gypsum Formation. Red colours and common calcretes suggest arid to semi-arid climatic conditions. The onset of Garedu Red Bed deposition indicates a major geodynamic change with the onset of compressive tectonics of the Late Cimmerian Tectonic Event (LCTE), being strongest at the eastern margin of the northern Tabas Block. When traced southwards, the same tectonic event is expressed by extension, indicating a shift in tectonic style along the boundary fault between the Tabas and Lut blocks. The complex Upper Jurassic facies distribution as well as the spatio-temporal changes in tectonic regime along the block-bounding faults are explained by the onset of counterclockwise vertical-axis rotation of the CEIM in the Kimmeridgian. The block boundaries accommodated the rotation by right-lateral strike slip, transpressional in today's northern and transtensional in today's southern segments of the block-bounding faults. Rotation occurred within bracketing transcurrent faults and continued into the Early Cretaceous, finally resulting in the opening of narrow oceanic basins encircling the CEIM. Palaeogeographically, the GRBF is part of a suite of red bed formations not only present on the CEIM, but also along the Sanandaj-Sirjan Zone (NW Iran), in northeastern Iran and beyond, indicating inter-regional tectonic instability, uplift and erosion under (semi-)arid climatic conditions across the Jurassic–Cretaceous boundary. Thus, even if our geodynamic model successfully explains Late Jurassic tectonic rotations, fault motions and facies distribution for the CEIM, the basic cause of the LCTE still remains enigmatic. [ABSTRACT FROM AUTHOR]

The Bakken Formation (uppermost Devonian-Lower Carboniferous) in North Dakota consists of black shales with a middle member composed of mixed siliciclastics and carbonates. Millimeter to decimeter-scale soft-sediment deformation structures (SSDS) are common in the upper third to quarter of the middle member, having been observed in sixty-three out of ninety cores studied. The nine categories identified herein reflect brittle and ductile deformation and loss of sediment shear in compressional and extensional settings. They are interpreted to form due to seismically-induced folding, liquefaction and fluidization of unconsolidated sediment, as well as microfaulting and brecciation of consolidated sediment, and reflect synsedimentary tectonic movements, e.g. along faults that were active during deposition. The distribution of SSDS follows the orientation of the major structural elements rooted in the basement of the Williston Basin. The stratigraphic and spatial distribution of SSDS suggests variable tectonic activity: cores near the most active fault systems have the highest net thickness of units with SSDS, whereas those farther from the most active faults exhibit only a few deformed units. The predominance of SSDS in the upper portion of the middle member suggests there was a change from relative tectonic quiescence to a more active regime which in turn led to modifications of basin geometry and new accommodation patterns. Synsedimentary deformation might have had a positive effect on reservoir quality in deformed units by increasing porosity and permeability as a result of cohesion loss and rearrangement of grains. Additionally, multiple injection structures and complexes of small-scale normal and reverse faults could contribute to better connectivity of reservoir units. • Abundant soft-sediment deformation structures in the middle Bakken member. • Soft-sediment deformation structures record syndepositional movement of basement structures. • Seismites can serve a tool to recognize paleotectonic activity in intracratonic basins. [ABSTRACT FROM AUTHOR]

Evidence for an extension-dominated tectonic phase in the late Early Cretaceous has been identified for the first time at Mt. Cosce in the Narni Ridge (60 km N of Rome, Central Apennines) as a result of geological mapping. There, the Umbria-Marche-Sabina pelagic succession overlies shallow-water carbonates (Calcare Massiccio Formation, Hettangian). The Mt. Cosce area represents a Jurassic pelagic carbonate platform-basin system, the inheritance of Early Jurassic Tethyan rifting, hosting a remarkable stratigraphic unit named the "Mt. Cosce Breccia". This is a sedimentary breccia, bearing clasts of Calcare Massiccio and of pelagic units and forming sparse to laterally continuous outcrops, which rests unconformably on the horst-block Calcare Massiccio. The polygenic breccia is chaotic and displays heterometric clasts made of rocks not younger than the Early Cretaceous, white pebbly mudstones with radiolarian- and calpionellid-rich (Maiolica Formation) elements and a Maiolica-type matrix. The lithoclasts were clearly sourced locally and represent formations from the Calcare Massiccio to the Jurassic basinal and condensed pelagic carbonate platform units. The age of the polygenic breccias is assigned to the "middle" Barremian due to the youngest age detected within the clasts, the occurrence of Hedbergella cf. H. luterbacheri in the matrix, and calcareous nannofossils. The unconformity and breccia indicate an episode of exhumation of an original Jurassic paleoescarpment tract that had by then been buried by the lower part of the Maiolica Formation. The clasts were sourced from the exhumed vestiges of the Jurassic onlap wedge (hangingwall-basin succession), the peritidal pre-rift substrate and its condensed drape (pelagic carbonate platform-type deposits), as a product of escarpment rejuvenation, erosion, and displacement along an Early Cretaceous fault. Unlabelled Image • The "Mt. Cosce Breccia" is a synsedimentary tectonic-related deposit. • Calcareous nannofossil biostratigraphy indicates a "middle" Barremian age. • Cretaceous normal faulting displaced a Jurassic rift architecture. • Rock falls backstepped the Cretaceous scarp and rejuvenated a Jurassic margin. [ABSTRACT FROM AUTHOR]

Located in northern Niger, the NW–SE Téfidet trough is the western branch of the Ténéré rift megasystem. Here we present a tectono-sedimentary analysis of the Téfidet trough, based on the combined use of satellite imagery, field observations and measures, and available literature. We use these data to analyse the sedimentary facies and the tectonic deformations (faults, folds, basins) in the Téfidet trough, and derive their relative chronology. Doing so, we characterize synrift and postrift deformations and their interactions with sedimentation. Altogether our analyses suggest that the Téfidet trough was affected from the Cretaceous to the Paleogene by three major tectonic periods. • The first period was a rifting stage with extension and transtension during the Albian–Aptian times. The mean extension was ∼N60° and dominantly produced NW–SE-trending normal faults, a few strike-slip faults locally associated with small folds with sigmoidal axis and small reverse faults, and progressive unconformities. • the second period was also a rifting time, which prevailed during the Upper Cretaceous. The regime was marked by transtensional to extensional tectonics, under a ∼N130° shortening and a ∼N60° trending stretching. The end of this period saw the closure of the Téfidet trough. • the third period was a postrift stage. It was characterized by a ∼N70° extensional to transtensional regime during the Oligocene–Pliocene. It mainly produced post-sedimentary extensional faults and fractures and alkaline volcanism. We eventually discuss these deformation phases in relation with the Cretaceous Gondwana breakup and its related rifting events in West and North Africa, and with the subsequent Africa–Europe collision. [ABSTRACT FROM AUTHOR]

Abstract High-frequency depositional cycles are often used for long-distance correlations within sedimentary basins and constructing high-resolution chronostratigraphic scales calibrated to the orbital clock. Such an approach has been used for the tropical, epicontinental Muschelkalk Sea covering most of Europe in the Middle Triassic. This paper aims at establishing the spatial extent and internal architecture of shallow-marine Muschelkalk cycles within a small (120 by 50 km) area of the Germanic Basin, to identify their local vs. regional distribution and cycle-forming mechanisms. Three groups of cycles are distinguished: 1) peritidal cycles representing a tidal flat-lagoon system which experienced longer periods of emersion; 2) shallow subtidal cycles formed around the fair-weather wave base; and 3) deep subtidal cycles developed around the storm wave base. The three cycle types differ markedly in the composition, facies homogeneity, sedimentary trends, hierarchical organization, continuity, and degree of lateral changeability and complexity, which collectively translates into the ease of cycle recognition. Despite the differences, the defined cycles do not extend laterally beyond the studied area and have laterally variable facies heterogeneities, sedimentary trends, and thicknesses. This variability resulted from more or less mosaic infilling of accommodation space, reflecting local bathymetry, physicochemical conditions, and carbonate production and accumulation rates on the platform. Accommodation space evolved by the interplay of eustatic sea-level fluctuations regional subsidence, and synsedimentary tectonic-block movements, but the contribution of these factors changed over time and was to varying degrees masked for each of the three cycle types by intrinsic sedimentary processes. The study shows that Middle Triassic cycles of the Germanic Basin have a local to sub-regional distribution and thereby are inappropriate for basin-wide correlations and chronostratigraphic inferences. It also strengthens the opinion of several workers that correlation of idealized cycles is unrealistic without checking the horizontal continuity of facies and key surfaces directly in the field. [ABSTRACT FROM AUTHOR]

Abstract The lower Cambrian Lalun Formation of the Tabas Block, Central Iran, allows to generate a sequence stratigraphic model which characterises the sedimentary evolution and improves palaeoenvironmental interpretation of sedimentary successions along the northern margin of the Prototethys. This formation provides a key for understanding processes that took place during the late early Cambrian in Iran and is the best representative for the complex mosaic of mixed siliciclastic-carbonate systems which illustrate the development and evolution of fluvial and tide-dominated estuarine systems adjacent to an open coast during this interval in the region. Detailed facies analysis allows to differentiate five vertically-stacked groups of facies associations (fluvial facies associations; estuarine facies association; open coast tidal flat facies association; carbonate ramp facies association; and delta facies association) in the uppermost interval of the Lalun Formation. The conceptual depositional models for the siliciclastic-carbonate successions of the Lalun Formation are summarised in a sequence stratigraphic framework, including three third-order depositional sequences (braided fluvial systems; incised-valley fill; and carbonate ramp and tide-influenced delta systems). The data suggest that the Central Iranian Microcontinent broke up during latest Neoproterozoic–early Cambrian times, resulting in the Proto-/Palaeotethys rifting, with considerable differential subsidence recognizable from the reactivation of faults in the early Cambrian which led to new syn-rift successions. The mosaic pattern of deposition observed among the studied sections suggests a compartmentalization of the depositional setting as a result of the interplay between tectonics, sediment supply, and eustasy. Abrupt lateral changes in facies and thickness within the sequences depositional sequences suggest that deposition was controlled by repeated tectonic downdrop and uplift as a consequence of local syndepositional, extensional fault movements. Tectonic activities in the studied region controlled sedimentation and accommodation as well as the position of depocentres within the basin, and the stratal geometries within the sequences. However, the stratigraphic architectural style of the depositional sequences and the asymmetrical trend of the transgressive and regressive second-order sequences imply that the deposition of the late early Cambrian successions is at least partly a result of eustatic sea level changes and cannot be linked exclusively to differential subsidence due to fault movements. Our study indicates that stratigraphic relationship between carbonate and siliciclastic facies in the depositional sequences was also controlled by subsidence/uplift in the hinterland and the areas of siliciclastic input rather than climatic changes. The late early Cambrian depositional environments evolved from braided rivers and an incised valley system (lowstand) to transgressive incised-valley-fill successions which are capped by transgressive open coast tidal flat and carbonate open marine facies. Depositional history of the formation terminated with a regression that ceased with progradation of tide-influenced delta systems. The stratigraphic evolution described in this study documents an eustatic sea-level fall interposed between the top of the Lalun Formation and the base of transgressive tidal bars of the overlying Fasham Formation reflecting the complex (sub-)globally recognizable regressive–transgressive event at the lower–middle Cambrian boundary interval, which led to the establishment of an extensive middle–late Cambrian carbonate platform in present-day northern and central Iran. Highlights • Stratigraphic analyses of the early Cambrian Lalun Formation has been conducted. • Synthesis of tectonic and eustatic controls on stratigraphic architecture. • The depositional models were proposed based on sequence stratigraphic framework. • Results are useful for correlation to Cambrian strata in other parts of Gondwana. [ABSTRACT FROM AUTHOR]

Miocene carbonates and marls in the northwestern margin of the Hyblean Plateau (SE Sicily) exhibit considerable thickness variations consistent with synsedimentary tectonism. In the Early-Middle Mio­cene carbonates (Ragusa Formation) a series of parallel swells dose to the platform edge encouraged the development of a coarse-grained bioclastic facies. The overlying Middle-Late Miocene marls (Tellaro Formation) thin over these seafloor highs and associated mafie Tortonian volcanics are particularly developed along the hinge zones between swells and local sea-floor depressions. The basic extrusives appear to have followed in­cipient NE-SW fault lines propagated from deeper basement fractures. During the succeeding Messinian these faults were activated to produce horst structures (Vallone Lamia horst, Monte Caratabia horst and Cameme horst). These separate locai NE-SW oriented narrow grabens in which thick Messinian evaporites were deposited, probably connected with the main Centrai Sicilian Basin. Further subacrial deposits and volcanics levelled the Hyblean horst and graben topography prior to the major Early Pliocene marine high-stand. The ensuing transgression covered the study area with a thick pelagic Early Pliocene chalk. Local regressions, the product of Middle Pliocene and Early Pleistocene major tectonic activity along the margins of the plateau, are associated with local unconformities. Final emergence along the margins of the plateau occurred at the close of Early Pleistocene times when the emplacement of the Gela Nappe, from the NE, partly filled the foredeep basin. The withdrawal of the sea from the foredeep occurred shortly afterwards.

The Neoproterozoic Cryogenian (‘Marinoan’) Ghaub Formation of northwestern Namibia represents an important founding pillar of the Snowball Earth hypothesis and its derivative, the Panglacial Earth hypothesis. These hypotheses assume oceans and continents covered by thick ice, even in the tropics, which caused a very distinct drop in eustatic sea-level. Over time, strongly increased CO 2 contents of the atmosphere led to sudden ice melting, very substantial sea-level rise, and strong weathering on the continents associated with the deposition of cap carbonates in the newly ice-free oceans. The ongoing controversy about Snowball-type glaciations in Namibia and elsewhere is reviewed, and other hypotheses (Slushball Earth, Waterbelt Earth, Jormungand state of the Earth, Thin Ice state of the Earth, Zipper-Rift Earth, High-Obliquity Earth) are discussed. We prefer the term ‘Waterbelt Earth’ instead of the originally proposed ‘Waterbelt state’ because of the clearer contrast with ‘Snowball Earth’. Because a great deal of information related to Cryogenian glaciations comes from the Ghaub Formation of northwestern Namibia, these hypotheses should be tested independently based on a time-equivalent depositional system. This analogue was found in the carbonate-dominated successions of the Otavi Mountainland (OML), northeastern Namibia, and is highly comparable with the successions in the well-investigated northwest of the country. An extreme eustatic sea-level drop caused by a global glaciation of oceans and continents and imposed on a carbonate platform or ramp such as the one in the OML would have led either to glacial cover or widespread subaerial exposure and extensive erosion, including deeply incised valleys. The presence of such features would strongly support the Snowball Earth hypotheses if tectonic effects did not play a major role. During the postglacial transgression, distinct reworking of the carbonate platform/ramp surface would have occurred, leaving behind lag deposits, as well as infills of incised valleys with fluvial, reworked glacial, and marine deposits. The main objective of our research was to weigh and investigate the strengths and weaknesses of the proposed Snowball Earth model of glacially induced large-amplitude sea-level changes during Ghaub time, and to compare different models to obtain a rough estimate of the amount of glaciation. The study area in the OML includes two different, age-equivalent facies realms: platform sedimentation in the Southern area without diamictites, and slope deposits, including Ghaub diamictites, in the Northern area. The southern, continuously shallow-marine area shows a shallowing-upward succession from the pre-glacial lower Auros Formation, often varve-like laminated shales formed below wave base, to metre-high columnar stromatolites and microbial mat-related carbonates with intervals of vertical tubes (degassing features) of the upper Auros Formation, overlain by cap carbonates of the Maieberg Formation. The columnar stromatolites and the microbial tubestone lithotypes were clearly deposited in the euphotic zone. Indications for tidal conditions or subaerial exposure were not recorded in this platform succession without unconformities. Neither dropstones, nor incised channels, nor transgressive lag deposits were observed. The facies changes from below storm wave base to the photic zone and finally a shallow subtidal zone is explained by a prolonged, modest sea-level fall, partly counterbalanced by subsidence, followed by a slow transgression. In contrast, coarse-grained sedimentary rocks (e.g., oolites, debrites) characterise the time-equivalent successions in the Northern area. Starting with laminated shales at the base, similar to the Southern area, the overlying redeposited oolites and breccias of the Auros Formation show distinct lateral and vertical inhomogeneities and thickness changes, which indicate long-lasting synsedimentary tectonism. The same phenomenon is observed in the overlying diamictites of the Ghaub Formation. Their variable clast content indicates erosion of a strongly uplifted local source area formerly covered by a thick carbonate succession, which was downstripped to the crystalline basement. The prograding diamictite succession with repeatedly intercalated silt-stringers is interpreted as periglacial debris flows into a marine environment. Sparse striated clasts in the diamictites and very rare dropstones (much less common than in northwestern Namibia) are indicators of glaciations somewhere in the area. However, compared with other glacial sequences, e.g. Quaternary periglacial sediments at the forefront of continental ice, dropstones and striated clasts would be expected to be much more common and more uniformly distributed if the entire area was covered by melting continental ice, as proposed in the Snowball/Panglacial Earth scenario. In the Southern area, dropstones would be expected to occur on the flooded platforms/ramps as well, even when diamictites are absent. Both the relatively moderate sea-level change and the less common, irregular distribution of locally concentrated glacial rainouts provide strong evidence against the presence of a thick, laterally continuous ice cover over oceans and continents extending to equatorial areas. The oceans possibly corresponded to the scenario of a Waterbelt Earth or High-Obliquity Earth; evidence of open oceanic water exists, which would have enabled the continued evolution of biota. Glacial ice was present on tropical continents, but its occurrences may have been regional in patches, sourced from mountainous areas, and ice streams would have reached the oceans only locally, unrelated to a thick continental ice cover. [ABSTRACT FROM AUTHOR]

The sedimentary succession in central Poland records significant changes in facies at the turn of the Planula and Platynota zones in the Upper Jurassic, expressed by the drowning of the ramp-type platform and development of an extensive isochronous marl horizon. The topmost level of the marl horizon is a regional hardground, which is interpreted as the third-order sequence boundary Kim 1. In some areas, the hardground was eroded and is only preserved as bored and encrusted clasts. The composition of the borings may indicate that colonization and recolonization of the clasts took place in an extremely shallow water environment. The overall low level diversity of clast-encrusting organisms and their occurrence on both sides of clasts indicates frequent overturning and high current activity. However, other extrinsic factors, such as salinity fluctuations, may have been involved. The final redeposition and burial of the clasts were related to subsidence through widespread reactivation of Paleozoic faults. Comparison with Middle Oxfordian-Lower Kimmeridgian sequences of central and southern Poland indicates that the carbonate ramp morphology and paleoenvironmental conditions were periodically subjected to significant modification during phases of extensional tectonics, with the development of fault-controlled intra-platform ridges and basins. These features may have been the NE continuation of parallel swells and basins developed in the southern part of the carbonate platform adjacent to the Tethys. [ABSTRACT FROM AUTHOR]

Neptunian sills at Rocca Busambra, a fragment of the Trapanese/Saccense Domain in western Sicily, host the most abundant ammonite and gastropod fauna which has ever been recorded from the Jurassic of the western Tethys. The fauna is dominated by parautochthonous organisms which were swept into the sills by gentle transport. Ammonites are characterized by perfect preservation and small size, a feature which is due to the predominance of microconchs but also of stunting. The most complete sill is 0.7 m thick and could be separated into 17 levels which range in age from the early Toarcian into the late Kimmeridgian, thus representing the most extreme case of palaeontologically and depositionally documented stratigraphic condensation in Earth history. The unique feature of the Rocca Busambra sills is due to the interaction of three processes: extreme stratigraphic condensation on the sea floor, weak tectonic fracturing of the host rock and repeated reopening on top of already existing sills. Contrasting percentages of gastropods in individual levels reflect sea-level oscillations which correspond to long known low- and highstands during the Jurassic of the western Tethys. Comparisons with other ammonite-bearing sill faunas reveal several similarities, but represent only short-timed phases of tectonic pulses and deposition. [ABSTRACT FROM AUTHOR]

In the area of the present Po¾e¹ka Mt. braided alluvial fans wereformed during the Early Miocene above the subsiding Cretaceous-Palaeogene basement. Due to autocyclic processes, i.e. lateral migrationof flows due to vertical aggradation of longitudinal bars, ormigration of the main trench, small-scale fining-upward cycles wereformed. The complete succession of the alluvial deposits is composedof two fining-upward megacycles, which are the consequence of allocyclicinfluences, i.e. the pulsating character of synsedimentary tectonics.Megacycles were developed parallel to backstepping of thefront of the fault scarp towards the mountain massif, caused by normalfaulting along the active margin of an extensional basin. Thiskind of depositional style indicates that the Sava fault operated as anormal fault at the beginning of its life during the Early Miocene,probably the Ottnangian.

We describe soft-sediment deformation structures into the Upper Triassic cherty limestone outcropping in the Pizzo Lupo section (Central Sicily, Italy), pertaining to the deep-water palaeodomain of the Southern Tethyan margin. In the study section, mainly consisting of thin-bedded mudstone/marl alternations with bedded chert intercalations, some lithofacies have been separated on the basis of the abundance of the calcium carbonate/clay content and the overall textural features. The deformational structures, displaying different deformational styles as folded and faulted beds, disturbed layers, clastic dikes, and slumps occur mainly in the deformed horizons that involve marl-dominated lithofacies. Small-scale water-escape structures involve beds with nodular fabric. Synsedimentary faults affect the mud-limestone dominated lithofacies, which are characterized by fault-rotating blocks producing lateral thinning. These bodies appear to have moved coherently along an overall planar surface. We relate these soft-sediment deformations to slump sheets, associated with down-slope sliding of sedimentary masses. The deformation mechanism and driving force for these soft-sediment deformations are due essentially to gravitational instability and dewatering. Detailing, rotational (slump) and translational (glide) slides and water-escape are the main processes causing the distinguished deformational styles. The synsedimentary extensional tectonics that affected the Upper Triassic pelagic deposits was the triggering process responsible for the instability of the seafloor inducing loss of coherence of the unconsolidated sediments on the sea bottom, developing a large number of gravity-driven slides. The analysis of both of these SSDSs and their relationships with the structural scenario allow us to hypothesise that they are seismically-induced. [ABSTRACT FROM AUTHOR]

Synsedimentary tectonics caused significant differentiation of sedimentary environments of the Adriatic Carbonate Platform during the Kimmeridgian. The most important changes have been recorded in W and central Croatia: along the NW part in present day W Istria there was an emergence with bauxite deposits, while along the NE margin of the platform, in the Karlovac area, a former emerged area was submerged.Penecontemporaneously between these areas, in the wider area of Velika Kapela Mt., a shallow intraplatform trough was formed, characterised by deposition of dark mudstones with nodules and thin layers of cherts and thin interbeds of tuffs in the upper part of the succession. Occurrences of planktonic foraminifera, radiolarians, calcisphaeres and rare ammonites indicate the sporadic influence of the open sea. Along the margins of the trough, peri-reefal environments were established, with flourishing developments of different reef-building organisms – hydrozoans, stromatoporoids, corals and bryozoans.Reefs were continuously destroyed, and in this way derived material was reworked and transported towards the trough slopes. An enormous quantity of this material caused progradation towards the deeper central part of the area, which was gradually infilled and narrowed.In the final phase, the trough was completely infilled, and peri-reefal environments gradually disappeared, since they were covered by ooid bars, culminating in the establishment of shallow environmentsover the entire area.A similar situation was recorded in another contemporaneous, also tectonically formed environment – the Lemeš trough, stretching from the vicinity of Bihać in NW Bosnia towards the south into Croatia, into E Lika and N Dalmatia. This trough had direct communication with the open Tethys realm, and thin-bedded and platy limestones with chert and pelagic organisms, including common ammonites, were deposited within it. The Lemeš trough was also surrounded by coral–hydrozoan reefs, and it was infilled by the same depositional processes as the neighbouring trough in the area of Velika Kapela Mt., and finally covered by shallow-water deposits.Although both troughs were probably formed by the same tectonicact, and had approximately the same duration – during the Kimmeridgian and Early Tithonian – they differ according to their palaeogeographic and facies characteristics. The trough investigated in the Velika Kapela Mt. was isolated, surrounded by shallow-marine platform environments, and had only temporary, indirect contact with the open sea. The Lemeš trough had a continuous connection with the open sea, as indicated by the relatively rich assemblages of pelagic organisms, especially ammonites, and is characterised by abundant cherts. However, both troughs are characterised by similar depositional sequences: both are underlain and overlain by shallow-water carbonate deposits, and they represent a consequence of a specific depositional event caused by tectonic deformation (formation of pull-apart basins) within the inner part of the Adriatic Carbonate Platform.

Croatian geological literature during the mid nineteen-eighties andnineties was marked by the appearance of a new geotectonic conceptof the Dinarides proposing that the recent, very complex structuralsetting is a direct consequence of a specific palaeogeographic relationshipduring the Mesozoic, i.e. the proposed existence of twocarbonate platforms separated by a long-lasting deep marine area(interplatform trough).Although the idea was very interesting and provoked discussion,resulting in the questioning of formerly established concepts, detailedanalysis of available data indicate that the Karst Dinarides (ExternalDinarides) were formed by the destruction of a single, althoughmorphologically considerably variable shallow water carbonate platform.This platform was in some periods very dynamic because ofits palaeogeographic position during the Mesozoic, resulting in manyperiods of large-scale facies differentiation, especially during the LateCretaceous. The final disintegration of the platform area culminatedin the formation of flysch trough(s) in the latest Cretaceous and Palaeogene and the subsequent uplift of the Dinarides. Recently therehave been some misunderstandings resulting from the imprecise useof newly established terms, which are, by circular logic, used to connectrecent geotectonic relationships with Mesozoic palaeogeographywithout adequate material proof. Therefore, the terms Dinaricum andAdriaticum should be redefined and used only for description of therecent tectonic pattern, without implying a palaeogeographic component,since during the Mesozoic they represented a single entity.Additional confusion is added by different names used for thesame shallow water carbonate platform. Probably the best, althoughnot the ideal name is the most frequently used one: the Adriatic Carbonate Platform. Its duration may be estimated from the Late Lias tothe Late Cretaceous, representing the most important part of a thickcarbonate succession in the Karst Dinarides (ranging from Carboniferousto Eocene).

Platform carbonate deposits of the Karst Dinarides area have a stratigraphicrange from the Middle Triassic (or even Carboniferous insome places) to the Middle Eocene, forming a belt nearly 700 kmlong and, (after reduction by younger tectonics) 80–210 km wide.Besides their significant thickness (4500 to 8000 m) they arecharacterised by frequent lateral and vertical alternations of differentfacies, mostly associated with shallow marine environments.Environments ranging from peritidal through low-energy shallowsubtidal–lagoons, restricted inner platform shallows, high-energy tidalbars, beach and shoreface to reefal–perireefal predominate, but thereare also carbonate slope deposits and those representing temporarilydrowned platform facies and intraplatform troughs.The Jurassic to Cretaceous part of this carbonate succession hasbeen subdivided into 19 megafacies units (9 for the Jurassic and 10for the Cretaceous), the majority of which represent an inner part ofthe ancient Adriatic Carbonate Platform. Marginal parts of the platformare mostly buried, either by the recent Adriatic Sea along theSW margin, or younger deposits along the NE margin; at some localitiessuch Jurassic and Cretaceous deposits are represented by debritesand/or carbonate turbidites. An additional short review of the overlyingUppermost Cretaceous and Palaeogene deposits (4 megafaciesunits) enabled a better insight into the post-platform evolution.The very complex vertical and lateral alternation of differentmegafacies units, including emerged areas which were observedthroughout the studied sequence in different parts of the KarstDinarides, indicate the significant palaeogeographic dynamics of theregion. This variability resulted from interaction of the global eustaticsignal and local factors, including extensive organic production on thecarbonate platform and synsedimentary tectonics controlled by thespecific palaeogeographic position of the platform during its geologicalhistory.

Carbonate intraplatform basins are documented worldwide as peculiar synsedimentary tectonic features forming in rifted margins and especially in those cases where the direction of extension is oblique with respect to the rift axis. A detailed stratigraphy and facies analysis combined with subsidence history of the Upper Triassic-Cretaceous shallow-water carbonates outcropping in the Peninsula of Capo San Vito, representing the NW end of the Sicilian fold and thrust belt, has been performed. Three different sections, separated by faults and characterised by shallow-water and deep-water carbonate sedimentation, were distinguished. Their location and tectonic relationships highlight the occurrence of two structural highs (Monaco and Sparagio sections) separated by a structural low (Acci section). The Acci intraplatform basin, structured since the Pliensbachian, is characterised by mostly pelagic sedimentation with resedimentation of carbonate reef derived-elements from adjacent carbonate platform blocks. On the two structural highs, shallow-water sedimentation, since the Late Triassic, developed with progradational trends shedding out shallow-water elements towards the basin. The evolution of the narrow Acci intraplatform basin appears influenced by a transtensional regime creating a wedge-shaped basin. Backstripping analysis on the three measured sections was able to reconstruct subsidence curves, from which different evolutionary stages, marked by punctual synsedimentary tectonic activity, can be highlighted for the Late Triassic-Eocene time interval. Comparison with the adjacent basin system of Cala Rossa, located 30 km away eastward in the Palermo Mountains, allowed to recognise similar characteristics. The stratigraphic, sedimentologic and tectono-sedimentary common features, trend and kinematic of the paleofaults, and the same chronology of tectonic events, suggest that the two areas represent adjacent basins making part of a unique spindle-shaped basin system. Some variable evolutionary characteristics among the Acci and Cala Rossa basins, including the overall thicknesses, the thickness of the resedimented deposits, the occurrence of Upper Cretaceous shallow-water deposits only in the structural highs of the Acci Basin, are explained as features linked to the different location of the two basins with respect to the master fault. Many of the observed features are described from those rift systems where the direction of extension is not perpendicular to the rift axis, suggesting that this sector of the Southern Tethyan margin could be developed as an oblique rift system. [ABSTRACT FROM AUTHOR]

LiDAR and photogrammetry data are integrated to study an Early Jurassic extensional synsedimentary structure in the Italian Southern Alps. Airborne LiDAR data helped in getting geologic information in areas covered by vegetation, photogrammetry was applied to produce a high-resolution 3D textured model of the inaccessible parts of the outcrop. LiDAR and photgrammetric data were merged together producing a multi-resolution model. Key geologic boundaries and faults bounding the synsedimentary structure were digitized in a 3D geomodeling environment. The reconstruction yielded information about the structure kinematics and accumulated displacements. [ABSTRACT FROM AUTHOR]

Hie mapping and stratigraphie study of the Ordovician rocks in Los Barrios de Luna area (southern limb of Abelgas-Alba Syncline), allowed us to recognize a complex stratigraphy, conditioned by a synsedimentary tectonics, probably related to the intense volcanism observed further east. The stratigraphy of the Barrios Fm., mostly Middle to Late Cambrian age, is reviewed. An informal stratigraphie unit (El Ventorrillo beds), of Early?, Middle to Late Ordovician age, is renamed. Two Upper Ordovician-basal Silurian? formations are formally defined (La Devesa Limestone and La Serrona Quartzite), and the stratigraphy of the Silurian informal unit Getino beds is refined. The ferruginous crusts at the base of El Ventorrillo beds and Getino beds are interpreted as a result of alteration of volcanic materials. [ABSTRACT FROM AUTHOR]

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. [Copyright &y& Elsevier]

The 1:10,000 scale mapping of the southern part of the Aggtelek Plateau (Western Carpathians, Silica Nappe, NE Hungary) and the study of five sections revealed two Middle Triassic reef bodies. In the late Pelsonian the uniform Steinalm Platform was drowned and dissected due to the Reifling Event. A connection with the open sea was established, indicated by the appearance of gladigondolellid conodonts from the early Illyrian. Basins and highs were formed. In the NW part of the studied area lower - middle? Illyrian basinal carbonates were followed by a platform margin reef (early?-middle Illyrian; reef stage 1) developed on a morphological high. This is the oldest known Triassic platform margin reef within the Alpine-Carpathian region. The reef association is dominated by sphinctozoans and microproblematics. The fossils are characteristic of the Wetterstein-type reef communities. Differently from this in the SE part of the studied region a basin existed from the late Pelsonian until the early Ladinian. During the late Illyrian- early Ladinian, the reef prograded to the SE, and reef stage 2 was established. Meanwhile, on the NW part of the platform a lagoon was formed behind the reef. Based on our palaeontological study the stratigraphic range of Colospongia catenulata, Follicatena cautica, Solenolmia manon manon, Vesicocaulis oenipontanus must be extended down to the middle Illyrian. Synsedimentary tectonics were detected in the 1. Binodosus Subzone, 2. Trinodosus Zone - the most part of the Reitzi Zone, 3. Avisianum Subzone.

Abstract: In this paper we analyze the Jurassic and Cretaceous evolution of the buried northwards stretch of the Apulia Platform (Southern Italy) (Ombrina-Rospo Plateau – ORP), and adjacent Adriatic Basin. Exploration wells indicate that inner platform carbonate facies across the ORP in the Jurassic and Lower Cretaceous are capped, along a subaerial exposure surface, by Oligocene/Miocene carbonates. A NW-trending intra-platform basin (“Casalbordino Corridor”) was infilled with shallow- to deeper-water sediments in the late Early to Late Cretaceous interval, while platform margins were experiencing tectonic reactivation. The ORP-to-basin transitional belt formed a corner, defining a NW and a NE margin. The NW margin was essentially stationary. A syn- and early post-rift platform-toe bypass wedge formed when late Hettangian–Sinemurian extension produced the platform/basin relief. Export of platform material, coupled with a halt of faulting, made the platform/slope profile continuous in the late Early or early Middle Jurassic (possibly across an ooidal rim). Late Jurassic Ellipsactinia/coral reefs passed downdip into bioclastics. The Maiolica Fm. displays two cycles (M1, M2), where M2 onlaps the slope built by M1. In the Aptian, with lithospheric arching, a high angle fault rejuvenated the margin. Off this margin, a narrow basin, locked between the ORP and a pelagic carbonate platform, was largely infilled with turbidites sourced by the ORP, but the high hampered the dispersal of the sand fraction. The NE margin displays prograding ooidal to bioclastic clinoforms (Middle and Upper Jurassic) downlapping onto the rift basin. In the Lower Cretaceous, the platform recovered after a slow-down of carbonate productivity (M1/2 boundary). The Marne a Fucoidi Fm. thickens at the toe of, and seals, a fault backstepping the margin. Further backstepping occurred ∼5 km platformwards along a (Cenomanian?) normal fault, producing room for a rudist factory. A retreating rocky shoreline sourced breccias, while downdip the shallow water facies graded into the Scaglia Fm. basin along a ramp-like profile with low angle clinoforms, merging with turbidites. [Copyright &y& Elsevier]

Middle Triassic history of the Southern Bakony Mts. is outlined on the base of horizontal and vertical facies changes of the formations. During the Pelsonian (Balatonicus Chron) the evolution of the basins and platforms was determined basically by synsedimentary tectonics. The Felsõörs basin of the Balaton Highland opened due to the block-faulting of the Bithynian carbonate ramp (Megyehegy Dolomite). Above the drowning blocks „halfgraben” basins were formed (Felsõörs Formation), while isolated platforms developed on the uplifted ones in the middle part of the Balaton Highland and on the Veszprém plateau (Tagyon Formation). Due to the relative sea-level fall in the early Illyrian, the platforms became subaerially exposed and karstified. As a consequence of the late Illyrian tectonic subsidence (manifested by neptunian dykes) the central platform of the Balaton Highland has been drowned (Camunum Subchron). On the contrary, the Anisian platform of the Veszprém plateau was totally flooded only during the latest Illyrian (Reitzi Subchron) due to eustatic sea-level rise. It was followed by a short highstand period (Secedensis Chron), characterised by the first progradation of the Budaörs platform on the Veszprém plateau and highstand shedding in the basins and on the submarine high (Vászoly Limestone) in the centre of the Balaton Highland basin. Due to the following rapid sea-level rise, carbonate sedimentation continued in eupelagic basin from the Fassanian (Buchenstein Formation). At the beginning of the late Longobardian highstand period (Regoledanus Chron) the Budaörs platform intensively prograded from the Veszprém plateau to the southwest, causing highstand shedding in the Balaton Highland basin (Füred Limestone).

The Mannersdorf quarries at the northeastern edge of the Leitha Mountains (Lower Austria) preserve a record of pre-, syn- and post-tectonical phases of a Badenian carbonate platform in the Vienna Basin. The pre-tectonic phase is reported by a marine transgression with the development of a coastal slope scree and subsequent prograding of a Gilbert-type fan delta, overlain by very heterogeneous corallinacean limestones. A fault divides the study area into two independent tectonic blocks, which have been logged and subjected to detailed investigation and sampling. The corallinacean limestones of the first block indicate shallow-water environments (i.e., seagrass meadows) and gradual transitions from shallower to deeper environments, while the second block shows an unconformity, which is linked to a rapid facies change from relatively deeper environments (i.e., indicated by the abundance of in situ Pholadomya) to shallow waters (indicated by corals). Contrary to coral-bearing limestones of the same age at the southwestern part of the Leitha Mountains, corals are generally rare in the limestones of the Mannersdorf quarries, which represent mostly deeper environments with conspicuous differences in faunal associations. The onlap of limestones on a tectonic-caused flexure indicates syn-tectonical movements. Paleostress analyses verify a normal-fault reactivated as a dextral strike-slip fault. The temporal character of this fault is indicated by a post-tectonical phase with a marine transgression, a burial of the fault and neptunian dyke development. [ABSTRACT FROM AUTHOR]

The Prepiedmont domain succession of the Ligurian Alps is formed by a thick Mesozoic sedimentary cover tectonically detached from its substratum. The Arnasco-Castelbianco unit preserves the most complete record of the Ligurian Prepiedmont, although completely overturned and deformed due to Alpine tectonics. It is composed of carbonate and clastic rocks deposited during the Upper Triassic to Lower Cretaceous interval. This paper is focused on the stratigraphy of the Jurassic series and its relationships to the Tethyan rifting. Each term of the sedimentary record is seen as a witness of the several phases through which the rifting took place. An early rifting phase (Late Hettangian to Early Sinemurian) brought to the formation of a normal fault system affecting the carbonate platform and favoured the development of condensed sedimentation on pelagic highs. The rapid transition from open-platform carbonates to slope-basin cherty limestones testifies the increased subsidence of the margin in the Late Sinemurian, during which moderate fault activity is recorded (intraformational breccia horizons). Until the Early Pliensbachian, a tectonic pause brought to the sedimentation of a succession of pelagic carbonates, occasionally interrupted by clastic flows. During the Late Pliensbachian (?) to Toarcian, the rifting phase followed, evidenced by the large amount of clastics and generated by renewed fault activity. Clastics flowed down into the basin as fluxoturbidites first, and then passed to breccias during the maximum tectonic pulse. In the Late Toarcian to Aalenian (?), the thermal uplift of the Briançonnais shoulder generated a basin fill of fine clastics. The following thermal subsidence (Aalenian to Tithonian) favoured the restoration of quiet basinal conditions evidenced by the deposition of radiolarites. [ABSTRACT FROM AUTHOR]

Mt. Promina became famous for its coal mines, vertebrate remains and fossil flora, and for the use of its name in denoting sediments covering a wide area of the Dinaric coastal range. The Promina Beds of the type area, Mt. Promina, are up to 1 km thick and evolved in the context of propagating Dinaric deformation towards the foreland. They consist of eight sedimentary units differing in facies, i.e. depositional environments and systems, which include alluvial, lacustrine, deltaic, lagoonal and shelf deposits. The sedimentary units constitute three depositional cycles. Cycle I is represented by a late lowstand alluvium, while Cycles II and Ill consist of transgressive and highstand (regressive) systems tracts. Cycle III also includes a coastal onlap of limestones and an alluvial onlap. Transgressive tracts are specific in being represented by lacustrine deposits and having non-erosive bases. Falling-stage sediments have not been identified. The Promina Beds of Mt. Promina represent an example of sedimentary and sequence evolution at a foreland basin margin. The evolution of this margin is characterised by structural and stratigraphic complexities including syndepositional folding, growth strata, angular unconformities, intraformational faulting, alluvial and marine onlaps onto deformed basement, and tectonically induced, proximal-distal variations in facies and sediment thickness. The origin of lacustrine transgressive tracts may have been related to backtilting in the proximal part of the basin. High sediment supply and subsidence pulses are proposed to have been the two main factors which shaped the depositional styles, sequence development and distribution of sediments. The dominant role of tectonism in the sedimentary evolution was related to the position of the area within deforming; marginal parts of the foreland basin, situated in close vicinity to the main, active Dinaric thrust units. [ABSTRACT FROM AUTHOR]

Abstract: The creation of a complex submarine morphology on the passive margin of the Indo-Pakistan continental plate during later stages of its northward drift, just prior to collision with Eurasia, is clearly demonstrated by the nature, architecture and regional distribution of sandstone bodies within the Campanian–Maastrichtian successions (Mughal Kot and Pab formations), exposed within the north–south trending Kirthar Fold Belt of southwest Pakistan. These successions range in thickness from 7m to more than 500m and are dominated by fine to coarse, sometimes pebbly, thin to thick-bedded sandstones with subordinate mudstones and marls, all of which were deposited on the north-facing passive margin of the Indo-Pakistan Plate. Twelve facies have been identified in these sequences and these have been grouped into nine Facies Associations, which were formed within two broadly coeval depositional systems that occupied the contiguous Southern Kirthar and Central Kirthar sub-basins. It is argued here that these sub-basins and their fill-sequences developed mainly in response to major, tectonically induced changes in both the morphology of this sector of the palaeo-margin and in the sediment-supply systems. The more proximal sequences in the east and southeast sectors of the Southern Kirthar sub-basin are dominated by fluviodeltaic deposits while more distal areas to the northwest are characterized by turbidite sandstone bodies formed in channel-levee and lobe complexes within slope and basin floor settings of a relatively confined deep marine trough. In this Southern Kirthar sub-basin, the Mughal Kot Formation comprises basin floor lobes, submarine channel-fill sand bodies and base of slope mud-rich lobes, whereas the succeeding Pab Formation reflects overall progradation of the system, being dominated by submarine slope fan lobes, channels and levee deposits. The Central Kirthar sub-basin displays a broadly east-to-west transition from shoreface (inner shelf), through shelfal delta lobes (middle shelf) and deeper shelf/ramp (outer shelf) facies associations, all formed on a gently inclined, storm- and flood-dominated clastic ramp. Synsedimentary normal faults observed in this study were controlled the depositional architecture and creation of closed deep marine southern Kirthar sub-basin during Late Cretaceous. [Copyright &y& Elsevier]

The lateral continuity and facies heterogeneities of metre-scale cycles in a greenhouse Lower Jurassic (Sinemurian) carbonate ramp from the northern Iberian Basin (Spain) was evaluated from extensive field analysis carried out on a well-exposed 12 km long outcrop. Eleven high-frequency continuous cycles and their bounding surfaces are traceable laterally through the entire outcrop. However, three of these cycles are found to split laterally into discontinuous cycles of more limited distribution (up to 3 to 5 km of lateral extent). The continuous and discontinuous cycles have a similar field expression in one-dimensional logs. As a consequence, the number of cycles that can be differentiated is variable along the logged sections (i.e. from 11 to 16). Cycles have variable facies heterogeneities and sedimentary trends depending on the environment of formation: shallowing-upward and symmetrical cycles occur in protected lagoon–tidal flat areas and in the open-marine, high-energy domain. These cycles show significant facies heterogeneities, which were controlled mainly by lateral migration of a mosaic of facies over an irregular topography. Deepening-upward and aggradational cycles are generated in low-energy, sub wave-base, open-marine areas. Facies are laterally homogeneous, reflecting low potential for carbonate accumulation and inability to fill the created accommodation space in this low-relief and relatively deep area. Cycle boundaries are generated by stages of rapid accommodation gain, involving the flooding of the carbonate ramp; they are more likely to originate from regional tectonic pulses (related to the extensional tectonics operating in the northern Iberian Basin) rather than greenhouse low-amplitude eustacy. Discontinuous cycles tend to occur in thickened areas and are interpreted as originating from the infill of wedge-shaped accommodation space resulting from differential subsidence (i.e. local tectonic pulses). In conclusion, where thickness variations occur in extensional settings lateral continuity of cycles should not be expected. In less well-exposed, or in one-dimensional sections and in wells, it would not be possible to distinguish continuous from discontinuous cycles, or to understand such two-dimensional heterogeneities. Identification of unique cycle-forming mechanisms or attempting cyclostratigraphic long-distance correlation of cycles is unrealistic without a detailed analysis of the architecture of cycles in laterally continuous outcrops. [ABSTRACT FROM AUTHOR]

The Rocca Busambra ridge in western Sicily is a shallow to pelagic Meso-Cenozoic carbonate structural unit of the Sicilian Chain with a variety of tectono-sedimentary features. Palaeofaults, unconformities (buttress unconformity, onlap, downlap), a network of neptunian dykes with several infilling generations, several large hiatuses, different facies and lateral facies changes, and erosional submarine and subaerial surfaces are observed. Detailed fieldwork and structural analyses have indicated the occurrence of fault planes with different orientations. These data, combined with facies studies and physical-stratigraphy analyses, allow for the distinction of different depositional regions. A lateral change from an open-marine carbonate platform with a stepped fault margin (located in the westernmost sector) to a deeper basinal depositional setting in the east, in the context of an upper slope scalloped margin and base-of-slope systems with talus breccias, is envisaged here. Extensional to transtensional tectonic pulses punctuated the sedimentary evolution during Early Toarcian, Late Jurassic, Early Cretaceous, Late Cretaceous, and Early Miocene times. The collected data show that most fault planes have preserved their original orientations throughout the reactivation processes. The reconstructed Meso-Cenozoic tectono-sedimentary evolution is closely related to the late syn-rift and post-rift tectonic evolution of the Tethyan continental margin. [ABSTRACT FROM AUTHOR]

In the Causses platform (south-east France), Late Hettangian to Sinemurian deposits were interpreted previously as shallow-water carbonate ramp deposits. A new look at these deposits has shown a fault-controlled mosaic carbonate platform that is different from the carbonate ramp models. Within the platform mosaic, 15 lithofacies have been recognized, which are organized in four facies associations, including peritidal, restricted shallow sub-tidal, sand dunes and sub-tidal shelf facies associations. The rapid lateral and vertical facies changes, and the lack of consistent landward or seaward direction indicated by the pattern of facies changes, question the existence of a shoreline suggested by the traditional models for this region. Instead, the facies organization and cycle stacking pattern suggest deposition in a mosaic of intertidal islands between which sub-tidal restricted or open conditions could coexist in very close proximity. Such a platform mosaic would have been defined by tectonic activities along normal faults which segmented the shallow-water Causses platform. The facies and facies associations are arranged into metre-scale, peritidal and sub-tidal cycles that are also variable. Certain cycles show the same stacking pattern in all the sections and seem to be traceable over tens of kilometres. On the contrary, other cycles cannot be correlated; they are present only in specific sections and have a maximum lateral extension of 1 or 2 km. These metre-scale cycles stack to form four medium-scale cycles bounded by surfaces that display sub-aerial exposure features. Medium-scale cycles stack into two larger-scale cycles (tens of metres thick) and are bounded by well-defined karstic surfaces. Based on their lateral continuity and their stacking pattern, the metre-scale cycles are controlled probably by high frequency eustatic variations overprinting the topographic irregularities formed by differential subsidence of fault-bounded blocks. Episodic fault activities may reorganize the topography so that, even if eustatic changes may still be the major control of cycles, the expression and number of cycles could be different. Cycles of medium and large-scale are interpreted as being allogenic, controlled by changes in eustasy and/or subsidence rates as evidenced by their lateral continuity and the correlations of the large-scale cycles with third-order depositional sequences. [ABSTRACT FROM AUTHOR]

Abstract: In the Central High Atlas, N of Errachidia, three major reef horizons in the Bajocian carbonate series of the Atlasic Basin were studied recently. The results of the study are based on fieldwork with an emphasis on stratigraphy, morphology and sedimentary patterns of detailed field sections. The lower reef horizon is composed of smaller build-ups which developed during the Aalenian-Lower Bajocian interval. At that time the depositional environment favored the production of both basinal and platform facies. This reef horizon is located only on the southern platform rim. Its development within the trough was controlled by synsedimentary block tilting, triggered by rifting, which was related to an ancient fracture zones inherited from the Triassic. Formed during the later stages of a rising sea-level, this horizon reflects a high carbonate production on the southern platform area. In the basin area, the second reef horizon presents relatively larger bodies (“patch reefs”). It consists of two major reef levels, separated by an interval of marls interspersed with thin-bedded limestones, developed most probably during Early? to Late Bajocian. For the duration of this time, within two 3rd order sequences, progradational shelfal units extended the platform facies northward to the basin center, covering a large area. Within a long-term transgressive/regressive cycle, throughout the Middle Aalenian-Bajocian, these reef horizons changed their structural growth to aggrading stacking patterns. The third reef horizon belongs to the lower part of the upper member of the Tazigzaout Formation, and shows the same sedimentary evolution as the second reef horizon underneath. It fits into a 2nd order geodynamic regressive cycle (upper part of Upper Bajocian-Bathonian pp.). It appears, that the development of the second and third reef horizon’s forced the platform to prograde towards the N, NW and E during a late highstand, when accommodation was decreasing. However, depending on the complexity of the sedimentary systems, and on the interplay between tectonics and eustatic sea level changes, the interpretations of the depositional history of these reef horizons remain complicated. [Copyright &y& Elsevier]

The Upper Jurassic complex of Zegarowe Rocks is situated on the Kraków–Wieluń Upland in southern Poland. The complex is dominated by massive limestones representing carbonate buildups. The successive stages of carbonate buildup development include: colonisation, aggradational growth and progradation phases. In the colonisation phase, on top of loose peloidal-ooid sands micritic peloidal thrombolites developed. Peloidal and agglutinated thrombolites and stromatolites proliferated during the aggradational growth phase, whereas the progradation phase was characterised by shallowing and related development of agglutinated stromatolites with coprolites. The latter were the effect of periodical stabilisation of detrital sediments by microbial mats. The Zegarowe Rocks complex developed upon an elevation of the Late Jurassic stable northern shelf of the Tethys. This elevation was formed due to local decrease in subsidence rate, induced by the presence of a Palaeozoic granitoid intrusion in the shelf substratum. The carbonate buildups of the Zegarowe Rocks complex, initially developing as sediment-starved mounds upon fault-controlled intraplatform highs under strongly restricted background sedimentation rate, were replaced by agglutinated microbial reefs. [ABSTRACT FROM AUTHOR]

Abstract: The Peñas Rubias Syncline (southwestern Spain) exposes a well-preserved shallow-water platform succession containing a spectrum of facies corresponding to inner platform intertidal to supratidal environments, across to deeper-water middle to outer platform environments. Nineteen microfacies are recognized, which are grouped into seven facies association corresponding to: siliciclastic deltaic bars, mixed carbonate/siliciclastic shoals, carbonate mud mound boundstones, background platform carbonates, background platform siliciclastics, mixed tempestites and deep-water siliciclastic shales and sandstones. The age of the succession was determined mainly by foraminiferans and calcareous algae, which permit the succession to be assigned to the late Brigantian (latest Viséan). This upper Brigantian platform is the only record of sedimentation of this age in the region, and thus is key for interpreting the sedimentary and tectonic evolution of the Carboniferous rocks in Sierra Morena. Biotic and sedimentological features were analyzed in order to assess the controls on the sedimentation. Several factors have influenced sedimentological changes: turbidity, subsidence, siliciclastic discharges, storms and bioturbation. The siliciclastic discharges exerted a considerable control on the basal deposits, mostly in their percentage of quartz sand grains and as microconglomerates. However, they did not develop as large deltaic deposits, and their influence can be considered as virtually negligible in regards to the remaining part of the succession. Turbidity, as a result of higher percentage of silt and mud in suspension, seems to be the main factor controlling the change between the older intertidal deposits in the inner platform to the younger subtidal deposits of the middle and outer platform. As a result of the increase of the mud and silt in suspension, facies changed first to marlstones and nodular argillaceous limestones, and second, to predominantly calcimicrobial boundstones and shales in the uppermost part of the carbonate succession, as well as showing a marked change from photic-controlled benthic faunal and microfloral assemblages to assemblages more tolerant or better adapted to muddier dysphotic substrates. Bioturbation is also interpreted as one of the main controls influencing the different type of boundstones in the middle platform, permitting the vertical growth of dome-shaped mud-mounds or as sheet-like deposits. Storm influences seem to have exerted some control on the positive relief of the dome-shaped boundstones, which are usually capped by tempestites. The differential subsidence observed in the northwestern sector of the platform allowed the accumulation of many stacked dome-shaped mounds, a feature not recognized in southeastern parts. The general stratigraphical sequence seems to be controlled by eustasy and synsedimentary tectonics. The overall succession exhibits a pronounced deepening-upwards transgressive sequence from siliciclastic delta bars, mixed shoals, carbonates and shales of the middle platform with the growth of calcimicrobial boundstones and dark green shales, passing up into black shales at the top of the sequence, in the outer platform and, possibly, submarine slope settings. Although this transgressive sequence is in harmony with the 3rd-order glacioeustatic cycle defined for the late Brigantian in the western Palaeotethys, all these Brigantian rocks accumulated in a synsedimentary extensional regime, which is related to the initiation of a sinistral strike–slip regime, previously recognized as affecting only Serpukhovian and younger rocks in Sierra Morena. These synsedimentary faults allow us to recognize significant lateral variations in thickness over short distances. [Copyright &y& Elsevier]

The Late Permian/Early Triassic succession of the Central European Basin (CEB) was repeatedly affected by the tectonic pulses associated with the earliest phases of Tethyan and Arctic–North Atlantic rifting. Effects of the differential tectonic subsidence are particularly well recorded by unconformities, which form widespread sequence boundaries. Such unconformities are most obvious in areas occupied by fault-controlled intra-basinal highs (swells). In that areas, stratigraphic loss may comprise entire Lower and Middle Buntsandstein formations and in places remnant Middle Buntsandstein successions directly rest on Permian strata. Analysis of 3D-seismic data and well logs combined with high-resolution sedimentological logging of drillcores at the western margin of the Ems Trough (NW Germany) reveals details of synsedimentary tectonic control on sequence development. Early Triassic extensional faulting of basement blocks provided stepwise addition of accommodation space for continental sequences by growth faulting along north–south oriented fault zones blocks on the flanks of the East Netherlands High. This process is most evident during the development of the Hardegsen Unconformity, which is characterised by an amalgamation of succeeding unconformity surfaces in areas of structurally controlled intrabasinal highs. [ABSTRACT FROM AUTHOR]

Calcareous nannofossils were studied in the Paleogene sediments (Upper Paleocene–Lower Oligocene) in four wells onshore and offshore of Northern Sinai, Egypt. The sediments provided well preserved and diversified nannofossils. The nannofossil biostratigraphy records numerous hiatuses of different stratigraphic units in the sections. Hiatuses of considerable duration were recorded across the Paleocene–Eocene boundary, across the Lower-Middle Eocene boundary, and in the Middle-Upper Eocene/Lower Oligocene. The Upper Eocene sediments were not found in the offshore wells, but a shaly–marly succession with intercalations of limestone was deposited in the onshore wells. The partial absence of the Upper Eocene may be related to tectono-sedimentary processes (uplift and/or erosion). At the same time the onshore area seems to have been subjected to vertical movements with less intensity, because of the presence of Zone NP18.The paleoenvironmental settings of the sediments are discussed, based on the nannofossil assemblages. [Copyright &y& Elsevier]

The Sikhor Formation (new) is a predominantly siliciclastic sediment package intercalated between the marly-silty Baghamshah Formation (below) and the calcareous Esfandiar Limestone and Qal'eh Dokhtar Limestone formations (above). All stratigraphic evidence points to an Early Callovian age of the formation. The Sikhor Formation is restricted to the southern and central Shotori Mountains and consists of two members: The Kuh-e-Neygu Member (new) is composed of fluvialdeltaic conglomerates, sandstones, and siltstones grading into marly silt of the Baghamshah Formation. The overlying Majd Member (new) is characterised by mixed siliciclastic-carbonate sediments that record the interfingering of carbonate ramp sediments with fluvialdeltaic sands and silts. Evidence of erosional truncation of the underlying Baghamshah Formation and confinement of the siliciclastic sediment to a comparatively narrow, NNW-SSE elongated strip suggest that the formation had its origin in the asymmetric uplift of a westdipping tilted fault block in the southern Shotori Mountains that shed its sediment predominantly in a northern and eastern direction. After erosional levelling, the former uplifted areas were overgrown by the highly productive Esfandiar Carbonate Platform. The Sikhor Formation thus is evidence of an extensional tectonic pulse in the early Callovian and underlines that this area of the Tabas Block was a tectonically highly unstable area during most of the Jurassic. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper details the influence of syndepositional tectonics in controlling the architecture of a well-exposed confined turbiditic sandbody, which crops out in the eastern part of the Tertiary Piedmont Basin (Castagnola Basin, northern Italy). The Castagnola Basin was tectonically active during sedimentation of the sandbody, and the lateral distribution of turbidity-current deposits has been used to constrain both how the basin subsided and the impact of basin topography on flow behaviour and deposition. The sandbody occurs in the lower member of an Upper Oligocene–Lower Miocene turbidite system (the Castagnola Formation). The sandbody is ≈30 m thick and can be followed laterally for ≈1·8 km; it shows onlap terminations onto both northern and southern basin margins. The outcrop is sufficiently large to allow a detailed analysis of the facies and geometrical heterogeneity, as viewed approximately parallel to the average palaeocurrent trend (SW–NE). Correlation between 41 sedimentological logs reveals the diachronous development of a succession of sandstone packages (subunits). Nine vertically stacked and laterally juxtaposed packages have been recognized (subunits B to I from oldest to youngest), which reflect changes in basin floor accommodation as a result of synsedimentary tectonism. Each package shows the development of different vertical stacking patterns with thinning- and -fining-upward small-scale sequences and variable lateral facies arrangements, as a consequence of the position relative to the basin margins. The geometry, stratigraphic relationships, facies distribution and palaeocurrent directions indicate that turbidite deposition during accumulation of most of the sandbody was controlled by (1) synsedimentary tilting of the basin slopes; (2) the distribution of structural and depositional relief within the basin; (3) the thickness and volume of the turbidite flows; and (4) the angle of impingement of... [ABSTRACT FROM AUTHOR]

The island of Cres is located in the northern part of the Adriatic Sea. The island is built up of predominantly Cretaceous carbonates deposited in north-western part of extensive and long-lasting Adriatic Carbonate Platform. Owing to the influence of synsedimentary tectonics supported by eustatic changes during the latest Albian/Early Cenomanian, different sedimentary environments were established: from shallow intraplatform basin and related slope, across basin margin to protected shallow-platform. During the Early to Middle Cenomanian rudist communities (ichthyosarcolitid/caprinid/radiolitid)flourished along a relatively high-energy intraplatform basin margin. Fair amounts of coarse-grained bioclasts, derived almost exclusively from broken rudist shells, were deposited over a marginal depocenter. Contemporaneously, pithonellid wackestone-packstones containing microbioclasts and planktonic foraminifera were deposited basinward while marginal bioclastic sediments and limestone blocks of the basin margin origin were sporadically deposited within the basin. The opening of the Cres intraplatform basin was aborted and the basin was finally filled up during the Late Cenomanian. Since the Cres intraplatform basin was established at the beginning of the Cenomanian it probably represented the initiation phase in the north-western extension of the later Adriatic Trough development. [ABSTRACT FROM AUTHOR]