Marine Horizons Research Articles

New ctenacanth sharks (Chondrichthyes; Elasmobranchii; Ctenacanthiformes) from the Middle to Late Mississippian of Kentucky and Alabama

ABSTRACT Two new ctenacanthiform sharks representing two families, Ctenacanthidae and Heslerodidae, have been identified from the Middle to Late Mississippian marine sediments from Mammoth Cave National Park, Kentucky, and two Late Mississippian marine horizons in northern Alabama. The ctenacanthid, Troglocladodus trimblei, gen. et sp. nov., is known from isolated teeth from the Middle Mississippian St. Louis Formation and Ste. Genevieve Formation of Mammoth Cave and the Late Mississippian Bangor Limestone of northern Alabama. Troglocladodus gen. nov. is characterized by broad median cusps, pronounced longitudinal cristae, multiple intermediate cusps, and labiolingually shortened tooth bases. The heslerodid, Glikmanius careforum sp. nov., is known from isolated teeth and visceral arches from the Middle Mississippian St. Louis Formation and Ste. Genevieve Formation and the Late Mississippian Haney Formation, a Hartselle Sandstone-equivalent shale interval, and Bangor Limestone. Glikmanius careforum sp. nov. has proportionately distinct teeth among species of Glikmanius, with more robust and shorter cusps. The palatoquadrate of G. careforum has a short palatine ramus, otic process that is dorsoventrally deep and less expanded antero-posteriorly similar to Heslerodus and Dracopristis, and an elongated quadrate process like Heslerodus. The Meckel’s cartilage is less dorsoventrally deep than Dracopristis. These two new ctenacanth taxa add important information on the diversity of Ctenacanthiformes suggesting three major lineages within the order. Ctenacanths have a rich fossil history from the Late Devonian to the Middle Permian evolving a variety of tooth types and small to large body sizes.

Annibale Riccò and the catoptric proof of the Earth’s curvature

Phenomena as common as the daily rising or setting of the Sun can reveal, upon careful examination, something surprising and unexpected, which has been attracting scientific attention belatedly and had to wait long before being explained. From systematic observation of sunrises over the marine horizon, the Italian astronomer Annibale Riccò (1844–1919) unexpectedly claimed to have recognized a new and novel evidence of the Earth’s roundness, scrutinizing distorted images of the Sun reflected off waters. Others had previously come to a similar conclusion, but it was Riccò’s pioneering work that brought this “catoptric” proof of the Earth’s curvature to the scientific limelight of his time. The interesting debate ensued gave rise to more articulated interpretations of Riccò’s observations, including recovery of olden “dioptric” explanations. The catoptric model was eventually abandoned, as it does not adequately take into account the effects of atmospheric refraction and above all the observed phenomenon is not genuinely “reflective.” The argument is nevertheless correct in principle and retains historical and pedagogical interest.

The Survant Coal Member of the Linton Formation (Pennsylvanian) in Indiana

This study attempts to advance the understanding of the geometry of the Survant Coal Member of the Linton Formation (Pennsylvanian) in Indiana. We documented variability in the thickness and lateral extent of the coal beds present between the Mecca Quarry Shale Member of the Linton Formation and the Excello Shale Member of the Petersburg Formation—two transgressive traceable marine horizons. Our study was based on the detailed examination of 1,240 petroleum geophysical logs and coal test borehole logs throughout Indiana, and on previously collected data. The presence of multiple coal beds in the Survant Coal Member and variable thickness of the clastic partings create mapping challenges and difficulties in reliably evaluating coal resources, as well as stratigraphic uncertainties and confusion related to the nomenclature used for this coal. Because one to four coal beds occur between the Mecca Quarry Shale Member and the Excello Shale Member (namely, between the Colchester and Houchin Creek Coal Members of the Linton and Petersburg Formations), it is unclear which seams should be included in the Survant Coal Member. To better depict the complexity of the Survant Coal Member, we suggest that two additional locations be considered as reference sections. The first auxiliary reference section is Indiana Geological and Water Survey (formerly, Indiana Geological Survey) drill core SDH-366 (Petroleum Database Management System [PDMS] #150359) from Vanderburgh County (PDMS, 2018). This reference section represents the more southern part of Indiana where two coal benches are separated by a thick clastic interval. The second auxiliary reference section is drill core SDH-235 (PDMS #157302) in Greene County, representative of the central part Indiana where two distinct coal benches are separated by a relatively thin clastic parting. These two additional sections together with the current reference section (SDH-306 [PDMS #115871] located in Pike County in southern Indiana) capture the complexity of the Survant Coal Member more comprehensively than the current reference section alone.
 This study provides new data on the geometry of the coal beds within the Survant Coal Member that will allow more reliable future resource and reserve evaluation of this coal. In addition, we have also compiled information about mining, resources, and properties of this coal to provide a comprehensive reference for the Survant Coal Member in Indiana.

The dawn of the Cretaceous Period in the English South Midlands

The Early Cretaceous (probably Berriasian – Valanginian) Whitchurch Sands Formation of Oxfordshire and Buckinghamshire, English South Midlands, was deposited as coastal-marine and alluvial sediment along the northern edge of the Wessex Basin. The type succession at Whitchurch in Buckinghamshire includes a marine horizon, probably of Berriasian age. Alluvial sediments dominate the formation elsewhere and are tentatively linked to mid-Valanginian uplift of the nearby London – Brabant Massif. The Valanginian alluvial plain is thought to have bordered a coastal lagoon and barrier complex, accounting for non-marine faunas in the Whitchurch Sands Formation, and limiting seawater influx into the Weald Basin of south-east England, from a South Midlands seaway. Detrital and palaeobiological data from the Whitchurch Sands Formation and type Wealden (Weald Basin) suggests a connection between the seaway and the East Midlands Shelf, through much or all of the Valanginian – early Aptian interval.

A new chronostratigraphic and palaeoenvironmental framework for the end of the Messinian salinity crisis in the Sorbas Basin (Betic Cordillera, southern Spain)

New palaeontologic, sedimentologic, and Sr isotope data allow to reconstruct a high‐resolution chronostratigraphic and palaeoenvironmental framework of the continental‐marine transition at the Miocene–Pliocene boundary in the Sorbas Basin (Betic Cordillera, South‐eastern Spain). The presence of Reticulofenestra zancleana, Ceratolithus acutus, and R. pseudoumbilicus in a marine horizon sharply overlying the continental deposits of the Zorreras Member indicates that the Messinian salinity crisis ended in the Sorbas Basin synchronously with the other Mediterranean basins at the base of the Zanclean, within the MNN12a biozone. Our results suggest that the Zanclean flooding turned the Sorbas Basin into a shallow bay with limited exchange with the main Mediterranean basin, probably through narrow seaways connecting also the Almeria, Nijar, and Vera basins. Our results do not confirm previous hypotheses envisaging an older age for the return to fully marine conditions in the Sorbas Basin and is in a good agreement with the reconstructions suggesting that the Zorreras Mb. continental deposits are the local time‐equivalent of the latest Messinian Lago‐Mare phase during the last stage of the salinity crisis.

Geochemical and faunal proxies in the Westphalian A (Langsettian) marine horizon of the Lublin Coal Basin

The uppermost Westphalian marine horizon ( Dunbarella horizon) is especially important for correlation of Carboniferous deposits in the Lublin Coal Basin and in other basins of the Northwest European Carboniferous Basin. The Dunbarella horizon is characterized by cyclic sedimentation and consequent faunal spectrum variability, typical for Westphalian marine horizons of northwestern Europe. Palaeontological study of the Dunbarella horizon showed the presence of macrofauna representing different palaeoenvironments, from marine to brackish (non-marine) and freshwater conditions. The vertical sea level fluctuations and changes in seawater salinity resulting in palaeontological record changes do not link with geochemical proxies. TOC, redox-sensitive trace element concentrations, and V/Cr, Ni/Co and V/(V + Ni) ratios generally suggest that the Dunbarella horizon sediments were deposited under predominantly oxic conditions (with local exceptions during the initial phase of the Dunbarella ingression; Kopina 1 borehole).

Fauna and flora of Early Cretaceous Tetori Group in Central Japan: The clues to revealing the evolution of Cretaceous terrestrial ecosystem in East Asia

The Early Cretaceous Tetori Group in northern Central Japan was deposited in the eastern margin of the Asian Continent at mid-latitudes. It consists of two depositional stages: DS2 (Berriasian–late Hauterivian; mainly brackish environment with intercalations of marine horizons) and DS3 (Barremian–Aptian; freshwater environments only). Review of their faunal and floral compositions reveals that (1) two vertebrate fossil localities in DS3: Kaseki-kabe (upper part of the Kuwajima Formation) and Kitadani Dinosaur Quarry (Kitadani Formation) are assigned to the Barremian and the Aptian, respectively, and probably coeval to the Jehol Group in the Liaoning, northern China; (2) abundant freshwater bivalves occur in DS3, and the Trigonioides–Plicatounio–Nippononaia (TPN) assemblage is present only in the Kitadani Formation; and (3) stratigraphic change of plant assemblages in DS3 indicates that climatic change (warmer and dryer) occurred around the Barremian–Aptian boundary, which is concordant with the faunal change inferred from the choristodere-bearing assemblage in the Okurodani and Kuwajima formations to the crocodyliform-bearing assemblage in the Kitadani Formation. Vertebrate and invertebrate faunal as well as floral compositions of the Tetori Group are distinct from those of the Jehol Group. Paleoclimatic and/or paleogeographical conditions were probably different between two regions, and thus paleobiogeographical differentiation in East Asia is suggested in the Early Cretaceous.

New data on the development of the Dunbarella marine marker horizon in the Lublin Coal Basin (Poland)

Dunbarella marine marker horizon has significant stratigraphical importance for the Lublin Coal Basin — LCB (Poland). It sets the boundary between Westphalian A (Langsettian) and B (Duckmantian) and between paralic and limnic sedimentation at the same time. This marker horizon is also the base of the Lublin formation deposits where a main multi-seam coal deposits can be found. The horizon correlates with the Clay Cross Marine Band (England), the Katharina horizon (Germany, The Netherlands) and the Quaregnon horizon (Belgium). The paleontological material taken from recent boreholes provides new data about development of the Dunbarella horizon of the LCB.32 bivalve species have been encountered and can be assigned to 28 genera. Edmondia, Posidonia, Sanguinolites, Polidevcia, Phestia and Dunbarella are the most abundant in all profiles. Slightly less numerous are gastropods (9 genera), represented mainly by Glabrocingulum and Euphemites, and cephalopods (4 genera), represented mainly by Gastrioceras and Anthracoceras. Very frequent, although not so diverse, are the brachiopods, primarily inarticulate and represented almost exclusively by Lingula. Studies of macrofauna showed the presence of marker species and faunal assemblages typical of the Dunbarella horizon. A distinctive feature of this horizon which was observed was the cyclic sedimentation and associated variability of the fauna spectrum. This is typical for Westphalian marine horizons of Northwestern Europe, including those correlated with the Dunbarella horizon.

Carbon isotope signatures of latest Permian marine successions of the Southern Alps suggest a continental runoff pulse enriched in land plant material

The latest Permian mass extinction, the most severe Phanerozoic biotic crisis, is marked by dramatic changes in palaeoenvironments. These changes significantly disrupted the global carbon cycle, reflected by a prominent and well known negative carbon isotope excursion recorded in marine and continental sediments. Carbon isotope trends of bulk carbonate and bulk organic matter in marine deposits of the European Southern Alps near the low-latitude marine event horizon deviate from each other. A positive excursion of several permil in δ<sup>13</sup>C<sub>org</sub> starts earlier and is much more pronounced than the short-term positive <sup>13</sup>C<sub>carb</sub> excursion; both excursions interrupt the general negative trend. Throughout the entire period investigated, <sup>13</sup>C<sub>org</sub> values become lighter with increasing distance from the palaeocoastline. Changing <sup>13</sup>C<sub>org</sub> values may be due to the influx of comparatively isotopically heavy land plant material. The stronger influence of land plant material on the <sup>13</sup>C<sub>org</sub> during the positive isotope excursion indicates a temporarily enhanced continental runoff that may either reflect increased precipitation, possibly triggered by aerosols originating from Siberian Trap volcanism, or indicate higher erosion rate in the face of reduced land vegetation cover. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.201300004" target="_blank">10.1002/mmng.201300004</a>

The Carboniferous-Permian boundary at Carrizo Arroyo, Central New Mexico, USA

At Carrizo Arroyo southwest of Albuquerque, New Mexico,USA, an approximately 105-m-thick section of upper Paleozoic clastic and carbonate rocks yields extensive fossil assemblages of marine and nonmarine origin. Most of the section at Carrizo Arroyo belongs to the Red Tanks Member of the Bursum Formation, ~ 100m thick and mostly variegated shale, mudstone and siltstone of nonmarine origin, intercalated with some beds of limestone and shale of marine origin. Red Tanks Member fossils include palynomorphs, charophytes, plant megafossils, non-fusulinid foraminifers, fusulinids, bryozoans, brachiopods, gastropods, bivalves, nautiloids, eurypterids, ostracods, syncarid crustaceans, conchostracans, insects and some other arthropods, echinoids, crinoids, conodonts, fish ichthyoliths and bones of amphibians and reptiles. At stratigraphic levels 43m and 68m above the base of the section are Lagerstätten of plants, insects, crustaceans, eurypterids and other fossils that form unique Late Paleozoic nearshore arthropod assemblages. Most of the fossil groups from the Red Tanks Member have been used to support diverse placements of the Pennsylvanian-Permian boundary at Carrizo Arroyo. We review previous placement of the Pennsylvanian-Permian boundary in the Carrizo Arroyo section and present newly collected insect and conodont data. The insects indicate that the two Lagerstätten in the Red Tanks Member are of early Asselian age. The new conodont data include the presence of Streptognathodus virgilicus in the uppermost part of the Atrasado Formation, which constrains its age to the middle to upper part of the Virgilian and to a comparable position in the Gzhelian. The only biostratigraphically-significant conodont assemblage in the Red Tanks Member comes from a marine horizon near the middle of the member, and the assemblage is probably equivalent in age to the Midcontinent Streptognathodus nevaensis Zone, of early to middle Asselian in age. Asignificant amount of latest Pennsylvanian to earliest Permian time apparently is not represented by rock record at the Carrizo Arroyo section, most likely at a major disconformity at the top of the Atrasado Formation and smaller ones at the bases of depositional sequences in the lower part of the Red Tanks Member. Conodont biostratigraphy provides compelling evidence that Bursum Formation deposition was not simply driven by glacio-eustatic cyclicity, but in this area it was partly overprinted by local tectonics.

Reconsideration of Marine horizon on KD-0 deep drilling in the southern of the Kyoto Basin

Reconsideration of Marine horizon on KD-0 deep drilling in the southern of the Kyoto Basin

Palynology of late Palaeozoic sediments (Tupe Formation) at La Herradura Creek, San Juan province, Argentina

Vergel, M., December, 2008. Palynology of late Palaeozoic sediments (Tupe Formation) at La Herradura Creek, San Juan province, Argentina. Alcheringa 32, 339–352. ISSN 0311-5518. Palynomorph assemblages recovered from the Tupe Formation at La Herradura Creek, San Juan province, Argentina, are analysed. The middle section of the sequence includes a marine fossiliferous interval belonging to the Tivertonia jachalensis–Streptorhynchus inaequiornatus (T–S) Faunal Biozone, recently ascribed an Early Permian age. The section below the marine fossiliferous unit yielded palynofloras typical of previously described ‘Tupense’ assemblages. The palynoflora recovered from beds above the marine horizon is diverse, relatively well preserved and includes species never recorded from the Tupe Formation. This latter palynoassemblage includes species diagnostic of Early Permian palynofloras such as Converrucosisporites confluens (Archangelsky & Gamerro) Playford & Dino, Pseudoreticulatispora pseudoreticulata (Balme & Hennelly) Bharadwaj & Srivastava, Horriditriletes ramosus (Balme & Hennelly) Bharadwaj & Salujha, Anapiculatisporites tereteangulatus (Balme & Hennelly) Playford & Dino, Laevigatosporites colliensis (Balme & Hennelly) Venkatachala & Kar, Marsupipollenites triradiatus Balme & Hennelly, Protohaploxypinus sewardii (Virkki) Hart and Pakhapites fusus (Bose & Kar) Menéndez. Correlations with assemblages from western Argentina and other Gondwanan regions suggest an Early Permian age (not older than Asselian–Sakmarian) for the upper part of the sequence, supporting the age attributed to the T–S Biozone.

Deglaciation sequences in the Permo-Carboniferous Itararé Group, Paraná Basin, southern Brazil

The Late Carboniferous–Early Permian Itararé Group is a thick glacial unit of the Paraná Basin. Five unconformity-bounded sequences have been defined in the eastern outcrop belt and recognized in well logs along 400 km across the central portion of the basin. Deglaciation sequences are present in the whole succession and represent the bulk of the stratigraphic record. The fining-upward vertical facies succession is characteristic of a retrogradational stacking pattern and corresponds to the stratigraphic record of major ice-retreat phases. Laterally discontinuous subglacial tillites and boulder beds occur at the base of the sequences. When these subglacial facies are absent, deglaciation sequences lie directly on the basal disconformities. Commonly present in the lowermost portions of the deglaciation sequences, polymictic conglomerates and cross-bedded sandstones are generated in subaqueous proximal outwash fans in front of retreating glaciers. The overlying assemblage of diamictites, parallel-bedded and rippled sandstones, and Bouma-like facies sequences are interpreted as deposits of distal outwash fan lobes. The tops of the deglaciation sequences are positioned in clay-rich marine horizons that show little (fine-laminated facies with dropstones) or no evidence of glacial influence on the deposition and likely represent periods of maximum ice retreat.

Nautiloids of the Permian-Triassic Khuff Formation, central Saudi Arabia

ABSTRACT Nautiloids are described for the first time from the outcrops of the lower part of the Midhnab Member and the lower part of the Khartam Member of the Khuff Formation in central Saudi Arabia. The nautiloids from the lower Midhnab Member, including Tirolonautilus gr. hoernesi, were found at two localities, and are associated with conical shaped cephalopodes (bactritids), bivalves, brachiopods, foraminifers, algae and ostracods. The nautiloids were recovered from the most marine horizon of the Khuff Formation. The nautiloid fauna confirms the Late Permian (Changhsingian) age assigned to the Midhnab Member based on the foraminiferal assemblage. In the lower part of the Khartam Member, a single specimen of Tirolonautilus feltgeni n. sp. is described here. It occurs in association with other cephalopods (bactritids), bivalves, foraminifers, and ostracods. The specimen confirms the Late Permian age (late Changhsingian) assigned to the Lower Khartam Member based on foraminiferal and ostracod assemblages. This marine fauna is located within the latest Permian maximum flooding event of central Saudi Arabia. The Khuff Formation nautiloids are compared to other fauna in the Peri-Tethys, particularly the southern Alps, where similar forms are described. Their similarity confirms a Late Permian marine exchange between the Arabian platform and the Western Tethyan realm.

Localized Quaternary uplift of south–central England

The Early Quaternary of south–central England is characterized by uplift, as is indicated by the river gravels that extend intermittently from Oxfordshire, through Northamptonshire, to Lincolnshire. The earliest of these gravels contain abundant quartz and quartzite clasts derived from Lower Triassic conglomerates in the West Midlands, but later deposits contain progressively larger amounts of locally derived Jurassic sediments. This compositional change is associated with the incision of the rivers that flowed eastwards from the West Midlands. Subsequently, the headwaters of some of these rivers were diverted towards the Bristol Channel and their suspended material was deposited on the outer parts of the UK continental shelf and slope. The area of incised drainage (Gloucestershire to Lincolnshire) did not extend to East Anglia (in the east) or to Somerset (in the west). Both these coastal regions contain several marine horizons showing that the area of uplift did not include the whole of southern England. The uplift cannot therefore be attributed to eustatic changes in sea level. The area of uplift is centred on the broad topographic depression of the English Midlands and corresponds approximately to the outcrop of thick ( c . 1 km) Upper Triassic and Lower Jurassic mudrocks. We have used an Ordnance Survey 50 m × 50 m topographic ‘grid’ to estimate the amount of mudrocks that has been removed from the depression and 2D flexural unloading models to calculate the tectonic uplift that resulted, for various assumptions of the effective elastic thickness (which is determined by the flexural rigidity) of the lithosphere. The amount of material removed is in accord with what is known of the volume of Quaternary deposits offshore, and the uplift accounts for the incised plateau surfaces of the flanking Cotswold Hills and the high ground of Northamptonshire to the east, and the Forest of Dean and the hills of Herefordshire to the west.

La megaflora de la Formación Tupe (Carbonífero Superior-Pérmico Inferior), en la Mina La Delfina, San Juan, Argentina*

The flora of the Tupe Formation (Upper Carboniferous-Lower Permian), at La Delfina Mine, San Juan, Argentina. Two plant assemblages from three levels of the Tupe Formation at La Delfina mine, north of Cuesta de Huaco in the San Juan Precordillera are described. The first assemblage occurs at the lower part of the Tupe Formation (levels N1 and N2), and is referred to the NBG (Nothorhacopteris argentinica-Botrychiopsis weissiana-Gynkgophyllum diazii) Biozone, that characterizes the Upper Carboniferous of NW Argentina. The second association was obtained from a third level (N7), 55 m approximately above level N2. It is composed by scarce remains referable with doubts to Kraeuselcladus argentinus Archangelsky, which could suggest the presence of the Uppermost Carboniferous Interval megafloristic Biozone. Sixty meters above this level a fossiliferous marine horizon occurs with elements of the Lower Permian, Tivertonia-Streptorhynchus Biozone. Thus, the Tupe Formation, in the area of the San Juan Precordillera, is referred to the Upper Carboniferous -Lower Permian interval, and the fossiliferous section at La Delfina mine is proposed as a potential stratotype for the carboniferous-Permian boundary.

Depositional sequence architecture and filling response model of the Cretaceous in the Kuqa depression, the Tarim basin

The Cretaceous system of the Kuqa depression is a regional scale (second order) depositional sequence defined by parallel unconformities or minor angular unconformities. It can be divided into four third-order sequence sets, eleven third-order sequences and tens of fourth- and fifth-order sequences. It consists generally of a regional depositional cycle from transgression to regression and is composed of three sets of facies associations: alluvial-fluvial, braided river-deltaic and lacustrine-deltaic facies associations. They represent the lowstand, transgressive and highstand facies tracts within the second-order sequence. The tectonic subsidence curve reconstructed by backstripping technique revealed that the Cretaceous Kuqa depression underwent a subsidence history from early accelerated subsidence, middle rapid subsidence and final slower subsidence phases during the Cretaceous time, with the correspondent tectonic subsidence rates being 30—35 m/Ma, 40—45 m/Ma and 5—10 m/Ma obtained from northern foredeep. This is likely attributed to the foreland dynamic process from early thrust flexural subsidence to late stress relaxation and erosion rebound uplift. The entire sedimentary history and the development of the three facies tracts are a response to the basin subsidence process. The slower subsidence foreland gentle slope was a favorable setting for the formation of braided fluvial deltaic systems during the late period of the Cretaceous, which comprise the important sandstone reservoirs in the depression. Sediment records of impermanent marine transgression were discovered in the Cretaceous and the major marine horizons are correctable to the highstands of the global sea level during the period.

Latest marine horizon north of Qomolangma (Mt Everest): implications for closure of Tethys seaway and collision tectonics

The newly discovered marine horizon at Zhepure Syncline, north of Qomolangma, revises timing of the closure of the eastern Neo‐Tethys seaway in the central Himalayas. The marine Pengqu Formation conformably overlies a Lutetian shallow‐water carbonate platform and comprises shales interbedded with sandstones deposited in a neritic shelf environment. The strata are dated by nannofossils and foraminifera as late early Lutetian to late Priabonian age (NP15–NP20, deposited ≈ 47–34 Ma), indicating that the final closure of the Tethys seaway in this region occurred at ∼ 34 Ma. The newly discovered strata provide evidence about emplacement of a major thrust sheet south of southern Tibet prior to ∼ 37 Ma, which affected the regional climate.

Late Pleistocene records of littoral processes at the Tyrrhenian Coast (Central Italy): depositional environments and luminescence chronology

Two cliff-sites on the Tyrrhenian coast of central Italy have been investigated in order to investigate late Pleistocene depositional environments by microfacies analysis and chronostratigraphy by luminescence age estimations. Both sections cover the period from the Last Interglacial to the end of the Last Glaciation. In the Buca dei Corvi site an increasing rate of uplift is recognised, which is responsible for significant environmental change and formation of the modern coastal fault scarp at around 9 ka. In the Golfo di Baratti site the vertical succession of three marine horizons, previously recognised by Cortemiglia et al., (1983), is attributed to the OIS stages ⩾5c, 5a and 3 respectively. This cliff-section is affected by NNE–SSW orientated normal faults, confirming that extentional structural processes are still active. The coastal deposit of Stage 3, today located at 7m a.s.l., suggests abnormal high uplift rate if the position of the palaeo-shoreline was assumed at −40 to −50m. Both central Mediterranean coastal records strongly suggest that the eustatic sea-level has dropped to a smaller amount than that of the open oceans.

Continental-scale sequence stratigraphy of the Namurian, Upper Carboniferous and its applications to reservoir prediction

The search for Upper Carboniferous reservoirs can be aided by the development of a chronostratigraphic framework combining detailed sedimentological information with a template using the diagnostic ammonoid-bearing marine bands from onshore analogues derived from European, American and Canadian basins. Analysing Namurian successions constrains key sand-prone intervals, which include the upper Kinderscoutian, lower Marsdenian and top Yeadonian, from a number of depositional settings. A controversial issue for the Upper Carboniferous is the relative importance of high frequency and high magnitude glacio–eustatic sea-level fluctuations as a driving mechanism in the development of basin fill over the controls exerted through the prevailing tectonic regime, climate and sediment supply. The recognition and characterization of time-equivalent sea-level rises and, with greater significance for hydrocarbon exploration, sea-level falls, from a number of European basins attests to their influence. Candidate reservoirs can be constrained at various temporal resolutions and may also be restricted geographically. Significant candidate reservoirs include multistorey fluvial incised valley fills and deepwater sand-rich successions. The most productive onshore reservoirs are coarse-grained/conglomeratic fluvial intervals located in the base of incised valleys where a significant proportion of the subsequent valley fill is fine-grained estuarine sediments. There is potential for large hydrocarbon reservoirs within sand-rich deep water successions but their occurrence in tectonically complex or deeply buried areas has thus far precluded their exploitation. A chronostratigraphic framework established for the UK and Ireland can be applied to European basins and, in a more limited sense, to North America, where marine horizons can be matched. The application of this framework to the subsurface lies in the recognition of key candidate reservoirs and their likely occurrence, both geographically and temporally.