Nouvelles Données sur le Crétacé Supérieur de la Sardaigne Orientale

The stratigraphic distribution of the principal Upper Cretaceous facies in Sardinia ispresented, with special reference to the eastern part of the Island. Included are remarks on the mid-Cretaceous tectonic activity, which marks the base of the Upper Cretaceous depositional cycle. The presence of Upper Santonian and Lower Maastrichtian (the latter represented by marls with sparse turbidite interbeds) in the Lanaitto syncline (Oliena) is documented. Both contain outer-shelf assemblages rich in planktic Foraminifera. Recognition of rare detrital glaucophane in the Maastrichtian sandstones suggests a source area affected by high-pressure metamorphism, possibly corresponding to the southward extension of alpine Corsica.The Tertiary conglomerates exposed near Oliena include pebbles of facies (Campanienand Upper Maastrichtian rudistid limestones with larger Foraminifera) unknown in outcrop. A preliminary study of the rudists suggests a faunal exchange between different palaeobio-geographical provinces belonging, respectively, to the West European and Adriatic Plates.A palaeontological appendix contains remarks on some representatives of the family Heterohelicidae and on one species of Gunnarites found in the Lower Maastrichtian.     

A review of the Upper Campanian and Maastrichtian belemnite biostratigraphy of Europe

The conventional belemnite zonation of northwest Europe includes three Upper CampanianBelemnitellazones, two Lower MaastrichtianBelemnellazones, in addition to the lower Upper MaastrichtianBelemnitella juniorZone and upper Upper MaastrichtianBelemnella casimirovensisZone. These zones are critically assessed. Recent belemnite subdivisions of the Upper Campanian and Lower Maastrichtian are reviewed. The Upper Campanian of Norfolk has been subdivided into seven informalBelemnitellazones and subzones, and the Lower Maastrichtian of northwest Germany into six formalBelemnellazones. The timespan of the Early Maastrichtian zones is estimated and the duration varies from 0.12–0.60 Ma. It is shown that the base of the basal MaastrichtianBelemnella lanceolataZone is slightly diachronous, and the base of theB. casimirovensisZone is highly diachronous across Europe.     

New data on the palaeobiogeography of Loftusia genus (Foraminiferida). An in situ presence of the genus in eastern Greece (Boeotia)

An Upper Maastrichtian horizon rich in Loftusia is for the first time described in situ in Greece in the province of Boeotia. It is found in a continuous undisturbed carbonate sequence of the eastern Greece platform (Subpelagonian zone) of Maastrichtian–Paleocene age followed by flysch sedimentation. Loftusia is found in a facies reflecting an outer shelf environment, associated with debris of rudists, Orbitoides spp., Siderolites calcitrapoides, Omphalocyclus macroporus, Hellenocyclina beotica, Sulcoperculina sp., and echinoderms. Similar fauna, but without Loftusia, is found in the surrounding levels of Late Maastrichtian age as well. This recovery of the genus in the western part of its distribution area, where it is not as abundant as in the eastern part, is considered significant for the palaeobiogeography of the genus in Tethys Ocean during Late Cretaceous. To cite this article: A. Zambetakis-Lekkas, A. Kemeridou, C. R. Geoscience 338 (2006).     

Failure of landslide stabilization measures: The Sidi Rached viaduct case (Constantine,Algeria)

The goal of this paper is to document causes of the failure of stabilization measures undertaken for stabilizing a complex landslide threatening the Sidi Rached viaduct in Constantine, Algeria. Since the first instabilities, documented in 1910 during its construction, significant disturbances have been regularly observed on its eastern part and reinforcements carried out were only temporarily effective. Observed disturbances are inherently related to the fact that the eastern abutment and the three subsequent piers are built on unstable Maastrichtian marls whereas the remainder of the viaduct rests on stable Turonian limestone. The five main factors controlling the activation of the failure process are reviewed: (1) geomorphology, (2) geology, (3) human activities, (4) climate, and (5) seismicity. Data interpretation of two inclinometer surveys carried out close to the eastern abutment shows that the unstable mass moves westward, towards the Rhumel gorges. The main slip surface is located in the Maastrichtian schistose marl, at a depth ranging from about 8 m (west) to about 30 m (east). This translational slide is associated with a settling phenomenon due to the petrophysical properties of the unstable marl.     

Site selectivity of the boring Rogerella isp. infesting Cardiaster granulosus (Goldfuss) (Echinoidea) in the type Maastrichtian (Upper Cretaceous,Belgium)

A burrowing spatangoid echinoid (heart urchin), Cardiaster granulosus (Goldfuss), from the type area of the Maastrichtian Stage (Upper Cretaceous) in Belgium, was infested only in the plates of the ambulacral petals by acrothoracian barnacle borings, Rogerella isp. This infestation was after the death and exhumation of the echinoid. The distribution of Rogerella may indicate the azimuth of current flow at the time of exhumation prior to final burial. Copyright © 2015 John Wiley & Sons, Ltd.     

The Campanian-Maastrichtian stage boundary in the Aktulagai section (North Caspian depression)

Distribution of belemnites and benthic foraminifers in the Campanian-Maastrichtian boundary layers of the Aktulagai section, one of Upper Cretaceous reference sections in the east of the European paleobiogeographic region (EPR) is discussed. The base of Lanceolata Beds defined by A.D. Arkhangelsky in 1912 is well-substantiated biostratigraphic level corresponding to boundary between the Campanian and Maastrichtian stages. In spacious outcrops of Upper Cretaceous deposits in the Aktulagai Plateau (Aktyubinsk region, Kazakhstan Republic), “primitive Belemnella forms” (two rostra plates) appearing above that base distinctly replace the genus Belemnitella dominant in the Campanian. Seven successive zonal assemblages of benthic foraminifers (one plate) are established in the boundary interval. The Aktulagai reference section of Upper Cretaceous sediments can be used to trace the Campanian-Maastrichtian boundary from the eastern EPR to Boreal regions of Russia based on abundant micro-and nannofossils.     

Palynology of Upper Cretaceous (uppermost Campanian–Maastrichtian) deposits in the South Yellow Sea Basin, offshore Korea

Forty-seven samples from Upper Cretaceous sections penetrated by the Kachi-1 and Inga-1 wells in the South Yellow Sea Basin have been analysed for their spore and pollen content. Thirty-five species of 18 spore genera and 54 species of 28 pollen genera are documented. One new monotypic genus, Diporocolpopollenites, and its type species, D. kachiensis sp. nov., are erected, and Dilwynites Harris, 1965, and its type species, D. granulatus Harris, 1965, are emended. There are also three new combinations: Ephedripites eocaenicus (Selling, 1944), E. praeclarus (Chlonova, 1961), and Retitricolpites anguloluminosus (Anderson, 1960). Two palynological zones are erected: anAquilapollenites attenuatus Assemblage Zone, which encompasses deposits that are considered to be latest Campanian–Early Maastrichtian in age, and an Aquilapollenites eurypteronus Assemblage Zone for sections that have been dated as Late Maastrichtian. The assemblages are typical of the Yenisey-Amur Subprovince of the Aquilapollenites (floral) Province. Lowland floodplain to shallow, commonly mesotrophic, lacustrine environments of deposition are indicated. The climate was probably wet subtropical, with rainfall being somewhat higher during the Late Maastrichtian than through the latest Campanian–Early Maastrichtian.     

A re-analysis of the marine bird Asiahesperornis from northern Kazakhstan

Fossil bird material is exceptionally rare in the Mesozoic of western Asia. With the notable exception of the Upper Cretaceous foot-propelled diving bird Asiahesperornis bazhanovi from northern Kazakhstan, the only bird fossils described from this region have been bone fragments from the Upper Cretaceous of Uzbekistan. In this paper, all material referred to date to the hesperornithiform Asiahesperornis is reviewed and re-described. New postcranial elements of this taxon from the holotype Kushmurun locality (Maastrichtian Zhuravlovskaya Svita) are presented, and the taxonomic history and likely affinities of this ocean-going bird are discussed.     

The paleogeographic significance of Aquilapollenites occurrence in Pakistan

The occurrence of the genus Aquilapollenites in Upper Cretaceous and Neogene sediments of northwestern Pakistan is reported here. Aquilapollenites amplus, Aquilapollenites reductus, and Aquilapollenites sp. occur in the Maastrichtian palynomorph assemblage from an outcrop sample of the Mir Ali section, northern Waziristan. Aquilapollenites medeis in the Neogene Murgha Faqir Zai Formation of the Pishin Basin, Balochistan, is considered a reworked Cretaceous specimen. The Upper Cretaceous sediments of the Asian plate on the Tethys margin are considered to be the source of Aquilapollenites spp. in these samples.     

Osteichthyans from the Fairpoint Member of the Fox Hills Formation (Maastrichtian), Meade County, South Dakota, USA

The Fairpoint Member of the Fox Hills Formation (upper Maastrichtian) in Meade County, South Dakota, USA, contains an osteichthyan assemblage indicative of transitional to marine shoreface deposits. The fauna consists of: Lepisosteus sp., Paralbula casei, Cylindracanthus cf. C. ornatus, Enchodus gladiolus, Hadrodus sp., and indeterminate osteichthyans with probable affinities to the Siluriformes and Beryciformes. The Fairpoint fauna is of limited species diversity and in this character mirrors many other Upper Cretaceous North American osteichthyan assemblages. Comparison to Upper Cretaceous chondrichthyan diversity and consideration of the structure of Cretaceous marine food webs suggest that osteichthyans are strongly under-represented in the Upper Cretaceous of North America. The small size and poor preservation potential of many Upper Cretaceous North American osteichthyans probably account for much of this observed paucity. Fairpoint osteichthyans are members of families that survive the Cretaceous–Paleocene boundary extinction event. Some of these genera and families are still extant and occur in a wide array of modern fresh, brackish, and shallow marine environments.     

The Cenomanian–Turonian boundary on the Saharan Platform (Tunisia and Algeria)

Several transects made of correlated stratigraphic sections and well logs have been constructed spanning southern Tunisia and the Algerian Sahara (Tinrhert) for comparison with earlier results obtained in the Saharan Atlas. The study is based on facies analysis, sedimentology, biostratigraphy focused on ammonites and foraminifers) as well as whole rock geochemistry (δ¹³C). These suggest that the entire northern Sahara Platform underwent marine flooding that commenced just prior to the onset of the global positive δ¹³C shift documented for the Cenomanian–Turonian boundary. This flooding occurred in two phases. The first phase is expressed by the deposition of deeper-water, light-coloured bioturbated mudstones overlying the shallow-water deposits comprising the local Cenomanian successions. But in some places in the Central Sahara (Hassi Messaoud area, Tihemboka Arch) as well as in the Saharan Atlas, shallow-water carbonates kept up locally with the relative sea-level rise to build up isolated carbonate platforms. The topographic lows or saddles between these areas could have been formed through differential accumulation rates. During the second phase, flooding resumed and black shales were deposited over the mudstones in the saddles. The occurrence of black shales in these saddles is limited to the northern edge of the platform (Saharan Atlas of Algeria, Gafsa Trough in southern Tunisia). On the platform, this phase is represented by the same kind of mudstones deposited during the first phase of the flooding (southern Tunisia), or by ammonite-rich chalks in the intra-cratonic basin of the Tinrhert (southern Algeria). Black-shale deposition ceased in the early Turonian. Based on the δ¹³C curve, the latest Cenomanian flooding of the Sahara Platform is roughly coeval with that documented for the US Western Interior.During the first phase of the transgression, that is before the occurrence of the large Whiteinella of the W. archeocretacea Zone in the black shale unit, planktic foraminifers are dominated by small globulose forms of the Hedbergella delrioensis type, associated with Heterohelicidae. Keeled forms (rotaliporids, dicarinellids) are scarce and always very small when present. Perhaps these dwarfed forms were adapted to the restricted environments of the extensive intracratonic seaways crossing the Saharan Platform to the Benoué Trough in Nigeria.     

Late Cretaceous radiolarians of the genera Cuboctostylus Bragina and Hexacromyum Haeckel: Their stratigraphic and paleobiogeographical distribution

Recently, representatives of the genus Cuboctostylus Bragina (order Entactinaria) were included in the Upper Cretaceous radiolarian regional stratigraphic scale of Sakhalin. The Late Cretaceous species Hexacromyum pergamenti Bragina (order Spumellaria) has morphological similarity to representatives of the genus Cuboctostylus. Peculiar features of H. pergamenti internal structure are considered. Collections of Upper Cretaceous radiolarians from southern Cyprus, Serbia, northern Turkey, Crimean Mountains, East European Platform, northwestern Kamchatka, eastern slope of the Sredinnyi Range in Kamchatka, and Shikotan Island (Lesser Kurile Range) were used for the analysis of the taxonomic composition of Late Cretaceous representatives of the genera Cuboctostylus Bragina and Hexacromyum Haeckel as well as their stratigraphic and paleobiogeographic distribution. It is established that Cuboctostylus is distributed from tropical to south boreal realms. This genus is shown to exist through almost the entire Late Cretaceous: from the middle Cenomanian to initial Maastrichtian. Hexacromyum Haeckel populated both the south boreal realm and marginal areas of the Tethys Ocean in the Late Cretaceous. The new data presented may be used for distant interregional correlations. Cuboctostylus stellatus sp. nov. and several other Cuboctostylus taxa identified in open nomenclature are described; some morphological features of Hexacromyum pergamenti are specified.     

Bioistratigraphical and sedimentological study of Upper Senonian–Lower Eocene sediments of Tripolitza Platform in central Crete (Greece)

The stratigraphic and palaeoenvironmental implications of a section in the Upper Senonian to Lower Eocene carbonates of the Tripolitza Platform in central Crete are discussed in this paper. The lower part (upper Campanian–lower Maastrichtian) of the succession consists of about 75 m of thickly bedded, light to dark grey limestones, dolomitic limestones and dolomites that were deposited on an inner carbonate platform. It is characterized by stratified bioclastic rudist facies (shelly limestone) associated with foraminifera and especially with species of the Rhapydioninidae family. These are overlain by 35 m of crystalline light grey dolomites that were deposited on a very restricted internal platform, characterized by intertidal-supratidal facies. The overlying 75-m-thick light grey dolomitic limestones and dolomites are characterized by the presence ofRhapydionina liburnicaStache, and in the uppermost part byNeobalkhania bignotiCherchi, Radoicic & Schroeder, dating it as Late Maastrichtian. The facies, cryptalgal laminites with fenestrae of varying dimensions, suggest relatively extensive subaerial exposure. Possible pedogenic textures are common in this sequence and especially in the uppermost part, which coincides with the K/T boundary. The presence ofPseudonummoloculina heimi(Bonet) at two levels in the Maastrichtian succession suggests transportation of Middle-Late Cenomanian sediments from emergent blocks of the platform during this period. A gap is suspected, for regional stratigraphic reasons, between this horizon and the next which containsSpirolinasp. and “Pseudochrysalidina” sp., dating it as Early-Middle Eocene.     

New biostratigraphic data for the Chikkim Formation (Cretaceous, Tethyan Himalaya, India)

The Chikkim Formation as exposed in the Tethyan Himalaya (India) has been studied at its type locality, using planktonic foraminifera for a detailed biostratigraphic elaboration. Divided into two members, the Lower and Upper Chikkim members, this formation ranges in age from Albian to early Maastrichtian(?), and reaches a maximum thickness of 150 m. Examination of thin sections has yielded 34 species of foraminifera in five genus-level assemblages. The Lower Chikkim Member is about 55 m thick; its basal portion is of Albian age based on the presence of Biticinella breggiensis and Planomalina buxtorfi. At 26 m above the base, Whiteinella archaeocretacaea documents OAE 2 (Oceanic Anoxic Event 2), and thus the Cenomanian/Turonian boundary in this section. The carbonate sequence is capped by a Santonian-age hardground with iron oxide crusts and bioturbation. Macrofossils, including belemnites (at the base) and irregular echinoids (upper part), are present. The basal carbonaceous marls of the Upper Chikkim Member yield both large (benthic) rotaliid as well as planktonic foraminifera (Globotruncanita elevata, Gl. stuartiformis, Gl. stuarti, Gansserina gansseri and others), indicating a Campanian age. The co-occurrence of Gl. elevata and G. gansseri in a single thin section results either from condensation or reworking in the basal part of the Upper Chikkim Member. Late Cretaceous index foraminifera such as Gl. elevata document deposition within the Tethyan Realm. The original thickness of the Upper Chikkim Member is uncertain, but would have been around 100 m; the unit appears markedly reduced through weathering at a height of about 5000 m above sea level. Equivalent sediments are exposed in the Zanskar area to the northwest, and in Nepal and Tibet. Cretaceous Oceanic Red Beds (CORBs) are probably missing due to the proximality of these pelagic settings.     

New record of Bathonian–Callovian calcareous nannofossils in the eastern Karakoram block: a possible clue to understanding the dextral offset along the Karakoram Fault

We report the first record of Bathonian–Callovian calcareous nannofossils from a marine sedimentary sequence of the eastern Karakoram block, in northern India. The calcareous mudstones and packstones, occasionally bearing red chert nodules, yielded calcareous nanofossils and Middle Jurassic Choffatia furcula ammonoids. Middle to Upper Jurassic nannofossil assemblage is dominated by representatives of the genus Watznaueria. The occurrence of Ansulasphaera helvetica whose range is Upper Bathonian–Upper Callovian, indicates a correlation with nannofossil zones NJ12–13. The occurrence of Cyclagelosphaera wiedmannii further infer an Upper Bathonian–Callovian age. These specimens show affinities with those found in a similar sedimentary formation exposed in north Karakoram. This suggests the existence of a narrow and elongated sedimentary basin, oriented in a NW–SE direction, at a latitude of c. 25°–30°N. At that time, the Karakoram block was situated near the already welded Qiangtang block of Asia. The northern and eastern Karakoram blocks were connected during Middle Jurassic. The activity and dextral offset of the Karakoram fault separated the Jurassic sedimentary formations of the northern and eastern Karakoram blocks by c. 150 km.     

The distribution of calcareous nannofossils in the late Santonian–Late Maastrichtian deposits in the southwest of Iran (Khuzestan Province)

The first data on the distribution of calcareous nannofossils in the Behbehan section, the Kuh-e-Rish, are considered. According to the distribution of nannofossils, the Upper Cretaceous deposits of the section are subdivided into nine biostratigraphic zones. CC17 (Calculites obscurus zone) indicate the Late Santonian. Biozones CC18 (Aspidolithus parcus zone), CC19 (Calculites ovalis zone), CC20 (Ceratolithoides aculeus zone), CC21 (Quadrum sissinghii zone), and CC22 (Quadrum trifidum zone) represent the Campanian. Biozone CC23 (Tranolithus phacelosus zone) indicate the Late Campanian–Early Maastrichtian. Biozones CC24 (Reinhardtites levis zone) and CC25 (Arkhangelskiella cymbiformis zone) suggest the Middle and Late Maastrichtian, respectively. In the late Late Maastrichtian, due to decreasing in water depth at the study area, Nephrolithus frequens zone (CC26) defined in Tethysian domain was not recognized. The boundary between Gurpi–Pabdeh Formations represented a non-depositional period from the late Late Maastrichtian to the end of Early Paleocene. Also, it seems that predominant conditions of the sedimentary environment of Neotethys basin with the presence of index species calcareous nannofossils specified, which itself indicates that the warm climate and high depth of the basin in Late Santonian to Late Maastrichtian, in low latitudes has been prevalent.     

Late Maastrichtian litho- and ecocycles from hemipelagic deposits of eastern Sinai, Egypt

A biostratigraphical and palaeoecological survey employing calcareous nannofossils and planktonic and benthonic foraminifera has been carried out in four sections of hemipelagic marls and chalks of the Late Maastrichtian Abathomphalus mayaroensis Zone of eastern Sinai, in order to evaluate the mechanisms controlling the composition of the well preserved microfauna and nannoflora.The Abathomphalus mayaroensis Zone in eastern Sinai can be easily identified by the wide occurrence of the index fossil A. mayaroensis and can be further subdivided by the first occurrences of Plummerita reicheli (ex. P. hantkeninoides) and Micula prinsii. Microfossil abundances and lithologies are characterised by pronounced repetitive distribution patterns. These include low and high frequency fluctuations of the planktonic/benthonic (P/B) foraminiferal ratio, repetitive changes in the abundance of calcareous nannofossils and benthonic foraminifera, as well as the development of chalk-marl couplets and thinning upward chalk packets. both microfossil distribution patterns and the occurrence of rhythmites are attributed to changes in primary palaeoproductivity. Semiquantitative investigations of calcareous nannofossils and a few selected benthonic foraminifera yield evidence of the presence of high (HP) and low (LP) productivity assemblages.The interpreted HP assemblage is dominated by Glaukolithus diplogrammus, Manvitella pemmatoidea, Microrhabdulus decoratus and Micula murus and the benthonic foraminifera Neoflabellina jarvisi; the LP assemblage is characterised by Lithraphidites quadratus and Bolivinoides draco. However, further quantitative studies are necessary to reconstruct the exact composition of these assemblages and to explain deviatory developments. The chalk-marl couplets, thinning-upward chalk packets and the high frequency P/B patterns are interpreted to reflect productivity changes related to orbital forcing. These hemipelagites were deposited during the latest phase of the southern Tethyan upwelling system, which was active from the Santonian to the Late Maastrichtian with a peak in the Campanian. Termination of upwelling just before the K/T boundary also provides a good explanation for the change towards a palaeobathymetric control on foraminiferal distribution, as observed for the Palaeocene of central east Sinai.     

Further evidence of marine Cenomanian,lower Turonian and Maastrichtian in the Upper Benue basin of Nigeria (West Africa)

Field investigations in the Upper Benue rift basin of Nigeria highlight the necessity for a review of the Cenomanian-Turonian biostratigraphy of the area. Three ammonite zones of Vascoceras bulbosum (Reyment), Paravascoceras costatum (Reyment) and Pseudotissotia (Bauchioceras) nigeriensis (Woods) have been recognized at sections exposed at the quarry of the cement factory near the village of Ashaka. The sediments within the Vascoceras bulbosum zone also contain specimens of Exogyra olisiponensis (Sharpe), Kanabiceras septemseriatum (Cragin) and Epengonoceras dumbli (Cragin). These are all indicative of an uppermost Cenomanian age and reveal that at least the lower portion of the Gongila Formation as exposed at Ashaka is faunistically equivalent to the Pindiga Formation as exposed in the type section at Pindiga.The shales in the Gombe region in which Libycoceras ismaeli (Zittel) was found are probably part of the Maastrichtian Fika shales outcropping extensively in the northern part of the area. The discovery of Cyclolithes nov. sp. within Gombe sandstones at Dakiti near Kumo confirm that they are at least partially marine in origin and Maastrichtian in age. This could be considered as an additional evidence in favour of the presence of marine waters in the Upper Benue during the last part of the Cretaceous.     

The heterodont bivalve Maghrebella forgemoli (Coquand, 1862) from Cenomanian of Batna,northeastern Algeria: Palaeobiogeography,biostratigraphy and palaeoenvironment

In the northern Aurès Range near Batna, Algeria, the Cenomanian Smail Marls Formation consists of fossiliferous deposits rich in diverse benthic macrofauna, mostly dominated by bivalves, among them the carditid Maghrebella forgemoli (Coquand, 1862). Almost exclusively Cenomanian, the abundance zone of Maghrebella forgemoli is in the higher levels of Lower Cenomanian, extending from the Sharpeiceras schlueteri zone to the Mantelliceras dixoni zone and corresponds to a limited circalittoral interval with relatively low energy, soft substrata, and relatively cold temperatures. The distribution of Maghrebella forgemoli in Mountains of Batna evidences bathymetric variation controlled by the tectonic activity affecting the ante-Triassic and the Upper Cretaceous substrata and generating a system of tilted blocks, at the beginning of the uppermost Albian-Cenomanian and Turonian, in the eastern Atlasic domain that extends to central Tunisia.