Sequence stratigraphy of a Mesozoic carbonate platform-to-basin system in western Sicily

2009 ◽  
Vol 1 (3) ◽  
Author(s):  
Luca Basilone
Keyword(s):  
Continental Margin ◽  
Carbonate Platform ◽  
Late Eocene ◽  
Late Triassic ◽  
Sedimentary Evolution ◽  
Subaerial Exposure ◽  
Platform Margin ◽  
Western Sicily ◽  
Physical Stratigraphy ◽  
Basin System

AbstractSequence stratigraphic studies of the Triassic through Paleogene carbonate successions of platform, slope and basin in western Sicily (Palermo and Termini Imerese Mountains) have identified a sedimentary cyclicity mostly caused by relative oscillations of sea level. The stratigraphic successions of the Imerese and Panormide palaeogeographic domains of the southern Tethyan continental margin were studied with physical-stratigraphy and facies analysis to reconstruct the sedimentary evolution of this platform-to-basin system.The Imerese Basin is characterized by a carbonate and siliceous-calcareous succession, 1200–1400m thick, Late Triassic to Eocene in age. The strata display a typical example of a carbonate platform margin, characterized by resedimented facies with progradational stacking patterns. The Panormide Carbonate Platform is characterized by a carbonate succession, 1000–1200 m thick, Late Triassic to Late Eocene, mostly consisting of shallow-water facies with periodic subaerial exposure.The cyclic arrangement has been obtained by the study of the stratigraphic signatures (unconformities, facies sequences, erosional surfaces and stratal geometries) found in the slope successions. The recognized pattern has been compared with coeval facies of the shelf. This correlation provided evidence of sedimentary evolution, influenced by progradation and backstepping of the shelf deposits.The stratigraphic architecture of the platform-to-basin system is characterized by four major transgressive/regressive cycles during the late Triassic to late Eocene.These cycles, framed in a chronostratigraphic chart, allows the correlation of the investigated shelf-to-basin system with the geological evolution of the African continental margin during the Mesozoic, showing tectono-eustatic cycles. The first cycle, encompassing the late Triassic to early Jurassic, appears to be related to the late syn-rift stage of the continental margin evolution. The following three cycles, spanning from the Jurassic to Eocene, can be related to the post-rift evolution and to thermal subsidence changes.

Deciphering the geodynamic evolution of the Dinaric orogen through the study of the ‘overstepping’ Cretaceous successions

2020 ◽  
Vol 157 (8) ◽  
pp. 1238-1264
Author(s):  
Giuseppe Nirta ◽  
Martin Aberhan ◽  
Valerio Bortolotti ◽  
Nicolaos Carras ◽  
Francesco Menna ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Continental Margin ◽  
Late Jurassic ◽  
Carbonate Platform ◽  
Depositional Environments ◽  
Small Scale ◽  
Large Area ◽  
Geodynamic Evolution ◽  
Sedimentary Evolution ◽  
Platform System

AbstractAlong the Dinaric–Hellenic orogen, the Late Jurassic – Early Cretaceous ophiolite obduction over the Adria continental margin was sealed by sedimentation of clastic terrestrial deposits rapidly followed by a widespread carbonate platform system since the Early Cretaceous period. These Cretaceous sediments presently crop out over areas of varying extension, from several hundred kilometre wide undeformed continuous covers to small-scale tectonic slivers involved in the tectonic stack following the latest Cretaceous–Palaeogene collision. These deposits are unconformably sedimented above the units formed by the Late Jurassic to Early Cretaceous nappe stacking above the eastern Adria continental margin. We studied these deposits in a large area between western Serbia and eastern Bosnia. In the studied area, these deposits are divided into three lithostratigraphic groups according to their age, depositional environment and type of underlying basement. The Mokra Gora Group sediments (upper Aptian–Maastrichtian) were deposited on top of previously obducted and weathered ophiolites, the Kosjerić Group (Cenomanian–Campanian) overlies composite tectonic units comprising obducted ophiolites and their underlying continental basement portions, while the Guča Group (Campanian–Maastrichtian) exclusively rests on top of continental basement. The reconstructed sedimentary evolution of these groups, together with the comparison with the syn- and post-obduction deposits at the front of the ophiolitic nappe(s) in a wider area of the internal Dinarides (e.g. Pogari Group and Bosnian flysch), allowed us to clarify the obduction mechanisms, including their tectonic context, the changes in depositional environments and the timing of depositional and tectonic events, and, in a wider view, shed light on the geodynamic evolution of the Dinaric belt.

New dating and interpretation of the sedimentary succession of Fiumara Sant’Angelo (Peloritani Mountains ; southern Italy) : consequences for the Mesozoic palaeogeography of the central Mediterranean

2002 ◽  
Vol 173 (2) ◽  
pp. 171-184 ◽  
Author(s):  
Fabrizio Cecca ◽  
Salvatore Critelli ◽  
Paola de Capoa ◽  
Angelida Di Staso ◽  
Salvatore Giardino ◽  
...  
Keyword(s):  
Carbonate Platform ◽  
Sedimentary Cover ◽  
Upper Triassic ◽  
Late Triassic ◽  
Low Grade ◽  
Calcareous Nannofossils ◽  
Central Mediterranean ◽  
Sedimentary Evolution ◽  
Rifted Continental Margin ◽  
Sedimentary Succession

Abstract In the Peloritani Mountains an Alpine nappe stack, involving an Hercynian or older basement, is present. Some nappes involve a Meso-Cenozoic sedimentary cover, which starts with Upper Triassic-Hettangian continental redbeds (Verrucano), followed by Sinemurian neritic limestones and, up to the Oligocene, by marly-calcareous pelagic strata. Locally, Upper Triassic evaporites have been recognised. In the Sant’Angelo di Brolo valley, a peculiar sedimentary succession characterised by about 80 m of graded sandstones overlies the Verrucano redbeds. It has been described by Duée [1969] who ascribed it to the Alì Unit. Later on, Thery et al. [1985] interpreted the sandstones as fluvial deposits, Norian-Rhetian in age on the basis of pollens, and correlated them with the Sardinian « Keuper ». The finding of some ammonites and few nannofloras in the siliciclastic succession allow us to reach quite different conclusions. One ammonite specimen, collected in the uppermost part, shows morphological affinities with Spinammatoceras (M) tenax (Vacek), reported from the Middle Aalenian L. murchisonae Zone. Within the calcareous nannofossils, the presence of Lotharingius umbriensis in the lower part of the succession indicates an age not older than late Pliensbachian. However, the upper part of the same succession is characterised by the occurrence of Hexalithus magharensis, Triscutum tiziense, Watznaueria contracta, whose FO is early Aalenian. The petrographic study evidences that sandstones have two compositional groupings : a quartzose (quartzarenite to sub-litharenite) petrofacies of the continental redbeds (Verrucano), and a quartzo-feldspathic (feldspathic quartz-arenite to sub-arkose) petrofacies of the marine sandstones. The redbeds represent deposition by low gradient rivers and are similar to the composition of the Torrente Duno Fm in the Longobucco Group of the Sila Unit sedimentary cover. Their sources include abundant reworked quartz, felsitic volcanic, and low-grade metamorphic terrains. The overlying Middle Liassic-Aalenian marine sandstones testify an abrupt change in composition, reflecting changing source terrains. Its composition, including oversized feldspar grains, suggests gneissic/plutonic source terrains, added to the quartzose and metamorphic sources of the underlying fluvial sandstone. Identical changing detrital modes is testified in the Liassic formations of the Longobucco Group. These sandstone detrital modes mark the evolving early Jurassic rifted-continental margin of the Neotethys ocean. The studied succession shows characteristics unknown elsewhere in the Peloritanian Units, such as the presence of Mesozoic siliciclastic sediments younger than the « Verrucano » redbeds and the lack of terrains in carbonate platform facies above them. It has been deposited in a basin close to emerged areas, in which a clastic supply persists at least until Aalenian. Therefore, the Jurassic palaeogeography of the Peloritanian domain was more articulated than previously thought: pelagic areas were close to continental regions which supplied with siliciclastic detritus narrow basins, confined in grabens or half-grabens between emerged lands and sea-mounts. In the whole Jurassic of the Calabria-Peloritani Arc, siliciclastic marine terrains are known only in the Sila Unit. Here, Middle Carixian-Lower Domerian marls and sandstones in slope facies and an arenaceous turbiditic succession – late Domerian-early Toarcian in age (Longobucco Group) - have been described [Teale et Young, 1987]. There are close similarities in lithologies, tectono-sedimentary evolution, age and petrographic characters between these two sequences. The studied succession cannot be ascribed either to the Mandanici Unit, or to the Alì Unit. In fact, these units are affected by Alpine metamorphism and their Alpine cover is characterised by Upper Triassic evaporites followed by Jurassic and Cretaceous pelagic limestones and radiolarites. Its original bedrock is probably represented by the phyllites and marbles of the Piraino Unit, recently identified in the same region. In conclusion, the Sant’Angelo di Brolo succession was deposited in a marine environment between Pliensbachian (or Sinemurian) and Aalenian. Thus, both the late Triassic age and the fluviatile environment proposed for these terrains must be abandoned, as well as their correlation with the Sardinian « Keuper ».

The interaction between the Apula plate and the Calabrian Accretionary Wedge in the Northern Ionian Sea: tectonic-stratigraphic evolution and implications for subduction processes.

2021 ◽  
Author(s):  
Nicolò Chizzini ◽  
Andrea Artoni ◽  
Luigi Torelli ◽  
Alina Polonia ◽  
Jessica Basso ◽  
...  
Keyword(s):  
Carbonate Platform ◽  
Seismic Facies ◽  
Normal Faults ◽  
Accretionary Wedge ◽  
Ionian Sea ◽  
Seismic Profiles ◽  
Sedimentary Evolution ◽  
Platform Margin ◽  
Carbonate Platform Margin ◽  
Seismic Facies Analysis

<p>In the collisional setting of the Northern Ionian Sea, the Calabrian Accretionary Wedge, which represents the Southeastward prolongation of the Southern Apennines, is facing directly the subducting Apula plate, which is mainly made of Mesozoic to Tertiary Carbonate Platform. The aim of this contribution is to illuminate the structures and stratigraphic relationships between the frontal part of the orogenic belt, the foredeep and adjacent Apulian foreland. Because of the lack of exploration wells in these deep offshore basins, a detailed seismic facies analysis of six multichannel seismic profiles has been carried out to define the tectonic-sedimentary evolution of the study area.<br>Seismic interpretation allows to identify four main structural domains. The highly tectonized accretionary wedge is characterized by compressive tectonics. A narrow foredeep basin is filled by a thick (1,5–0,9 s TWT) Pliocene-Holocene subhorizontal succession and lies above buried normal faults. A massive carbonate succession of the Apulian Platform, shows reef and carbonate platform margin facies. A layered carbonate succession of the Apulian Platform is characterized by ‘'intra-platform'’ facies and located in the easternmost portion of the area. Seismic stratigraphic analysis allows to define two main regional unconformities with characteristic relationships with structural trends: i) the Messinian unconformity, related to a regional and significant erosion associated to paleokarst processes on the exposed Mesozoic Apulian Platform, is cut by an array of normal faults affecting the entire Apulian foreland and by reverse faults in the accretionary wedge; ii) the middle Pliocene Unconformity, an angular and erosive unconformity truncating the Lower Pliocene reflectors, is affected by normal faults in the foreland and by compressive tectonics in the Calabrian wedge that is progressively advancing.<br>Seismic data analyses shows that the compressive tectonics is currently active in the Calabrian Accretionary Wedge and concentrated in the innermost domains where thrust faults deform the sea floor. The Mesozoic Apulian Platform is affected by normal faulting driven by flexural bending since Lower Pliocene. The new structural map shows that transpressive and positive inversion tectonics is a common deformational style in the foreland that can be associated with the Dinaric-Hellenic subduction, which is synchronous with respect to Calabrian subduction. According to these observations, the compressive tectonics affecting the Apulia plate can be interpreted as related to both the Calabrian and Dinaric-Hellenic shortening processes. The interference of these two orogenic wedges with the Apulia Plate plays an important role in defining the tectonic evolution of the Northern Ionian Sea.</p>

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

Seismic evidence of the Messinian events in the Adriatic basin

2021 ◽  
Author(s):  
Alessandra Lanzoni ◽  
Anna Del Ben ◽  
Edy Forlin ◽  
Federica Donda ◽  
Massimo Zecchin
Keyword(s):  
Sea Level ◽  
Adriatic Sea ◽  
Carbonate Platform ◽  
Primary Role ◽  
Seismic Profiles ◽  
Northern Adriatic ◽  
Platform Margin ◽  
Gargano Promontory ◽  
Po Delta ◽  
Adriatic Basin

<p>The Adriatic basin represents one of several restricted basins located in the Mediterranean Area. It consists of the foreland of three different orogenic belts: the Dinarides to the East, active during the Eocene, the Southern Alps to the North, active since the Cretaceous time, and the Apennines to the West, active since the Paleogene. The Apennines had a primary role during the Messinian Salinity Crisis (MSC), conditioning the connection between the Adriatic basin, the Ionian basin, and the proto-Tyrrhenian basin. During the Messinian, the present Adriatic Sea was characterized by shallow water domains, where gypsum evaporites initially deposited and often successively incised or outcropped. </p><p>In the past 50 years, a massive dataset, composed of 2D multichannel seismic data and boreholes, was collected, covering almost the whole Adriatic basin in the Italian offshore. In this work, we interpreted the Plio-Quaternary base (PQb), based on available public datasets and on seismic profiles present in literature, which provided regional information from the northernmost Trieste Gulf (Northern Adriatic Sea) to the Otranto Channel (Southern Adriatic Sea). Here, we propose the PQb time-structural map, obtained by analyzing more than 600 seismic profiles. The PQb represents both the Messinian erosion and/or the top of the Messinian evaporites. It is characterized by a high-amplitude reflector, commonly called “horizon M” in the old literature. Principal findings concerning the Messinian event are summarized as below: </p><p>-The Northern Adriatic (Gulf of Trieste, Gulf of Venice, Po delta, Kvarner Area) reveals widespread channelized systems produced by the initial decrease of the sea level, followed by subaerial erosion, related to further sea level decrease. High-grade erosion involved the nearby Adriatic carbonate platform in the Croatian offshore, where deep valleys, filled with Last Messinian or post- Messinian sediments, cut through the limestones.</p><p>-The Central Adriatic (from the Po delta to the Gargano Promontory) displays a higher evaporites accumulation than the northern sector. Meanwhile, the Mid-Adriatic Ridge was already developing, along with the Apennine Chain, which was in a westernmost position. Erosional features in the deeper area are related to channelized systems, which followed the evaporites deposition. Meanwhile, also the Mid-Adriatic Ridge was affected by erosion.</p><p>-The Southern Adriatic (from the Gargano Promontory to the Otranto Channel) is characterized by the Mesozoic Apulia carbonate platform, covered by a thin Cenozoic sequence affected by subaerial erosion or non-deposition. The platform margin and the slope leading to the deepest South Adriatic basin, where a Messinian gypsum layer, also recorded in the Albanian and Croatian offshore, shows a lower level of upper erosion.</p><p>In general, we notice strongly variable thicknesses of the horizon M, which is related to submarine erosion (channels), subaerial erosion (discontinuous surfaces), non-deposition (possible unconformity), and tilting toward the surrounding chains (deepening horizons). In this work, we evaluate these different components from a regional point of view.  </p>

scholarly journals Tectono-thermal evolution of Oman's Mesozoic passive continental margin under the obducting Semail Ophiolite: a case study Jebel Akhdar, Oman

2018 ◽  
Author(s):  
Arne Grobe ◽  
Christoph von Hagke ◽  
Ralf Littke ◽  
István Dunkl ◽  
Franziska Wübbeler ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Continental Margin ◽  
Thermal Evolution ◽  
Carbonate Platform ◽  
Passive Continental Margin ◽  
Passive Margin ◽  
Temperature Evolution ◽  
Thermal Maturity ◽  
Solid Bitumen ◽  
Shear Sense

Abstract. The Mesozoic sequences of the Oman Mountains experienced only weak post-obduction overprint and deformation, thus they offer a unique natural laboratory to study obduction. We present a study of the pressure and temperature evolution in the passive continental margin under the Oman Ophiolite, using numerical basin models calibrated with thermal maturity data, fluid inclusion thermometry and low-temperature thermochronology. Thermal maturity data from the Adam Foothills constrain burial in the foredeep moving in front of the advancing nappes to be at least 4 km. Peak temperature evolution in the carbonate platform under the ophiolite is only weakly dependent on the temperature of the overriding nappes which have cooled during transport from the oceanic subduction zone to emplacement. Fluid-inclusion thermometry yields pressure-corrected homogenization temperatures of 225 to 266 °C for veins formed during progressing burial, 296–364 °C for veins related to peak burial and 184 to 213 °C for veins associated with late-stage strike-slip faulting. In contrast, the overlying Hawasina nappes have not been heated above c. 170 ºC, as witnessed by only partial resetting of the zircon (U-Th)/He thermochronometer. In combination with independently determined temperatures from solid bitumen reflectance, we infer that the fluid inclusions of peak-burial-related veins formed at minimum pressures of 225–285 MPa. This implies that the rocks of the future Jebel Akhdar Dome were buried under 8–10 km of ophiolite on top of 2 km of sedimentary nappes, which is in agreement with thermal maturity data of solid bitumen reflectance and Raman spectroscopy. Burial of the passive margin under the ophiolite results in sub-lithostatic pore pressures, in agreement with observations on veins formed in dilatant fractures in the carbonates. We infer that overpressure is induced by rapid burial under the ophiolite nappes. Obduction-related tilt of the passive margin in combination with overpressure in the passive margin caused fluid migration towards the south in front of the nappes. Exhumation of the Jebel Akhdar as indicated by our zircon (U-Th)/He data, integrated with existing data, started as early as the late Cretaceous to early Cenozoic, linked with extension along a major listric shear zone with top-to-NNE shear sense, together with an early phase of extensional dome formation. The carbonate platform and obducted nappes of the whole Jebel Akhdar cooled together below c. 170 °C between 50 and 40 Ma, before the final stage of anticline formation.

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