Late Albian Ammonites Research Articles

Quantitative biochronology by unitary associations of late Albian ammonites from Europe and their biodiversity

Quantitative biochronology by unitary associations of late Albian ammonites from Europe and their biodiversity

Late Albian ammonites from northwest Algeria: Biostratigraphic, paleobiogeographic and paleoenvironmental inferences

Albian rocks of northwest Algeria are commonly clastic deposits with poor dating markers. This study records two late Albian ammonites from northwest Algeria for the first time. They are Elobiceras (Elobiceras) sp. and Pervinquieria (Pervinquieria) pricei (Spath). These ammonites are collected from the Mcharref Formation interpreted here to be deposited south of Tiaret city under a lagoonal carbonate ramp setting based on facies analysis. The recognition of the well-known early late Albian ammonite Pervinquieria (Pervinquieria) pricei biozone from the study area highly improves the assigned age for the studied sections. The unconformity surface separates the lower and upper members of the Mcharref Formation coincides with the upper boundary of this biozone. The correlation of this boundary with the global sequence boundaries in the frame of ammonite biozones reveals that it equivalent to the SB KAl 6 (∼103.8 my ago) that marks the end of the identified biozone everywhere. Therefore, the recorded biozone shows an excellent correlation between the study area and that of Tethyan, European, American, and Asian biozones. Paleobiogeography of the recognized biozone indicates a cosmopolitan distribution that is interpreted here as a response to the widespread distribution of the Tethyan shallow water that reached to form a connection with the northern and southern Atlantic oceans during the late Albian time.

First discovery of nautilids from the Albian\u2013Cenomanian succession of the Koppeh Dagh Basin, NE Iran

The Aitamir Formation, situated in the Koppeh Dagh Basin in the northeast of Iran, is known for its well-exposed Albian-to-Cenomanian succession. Although geologists previously documented a number of macro- and microfossils, no nautilids had been discovered until now to our knowledge. Here, we present lower Albian and middle Cenomanian nautilids from the Koppeh Dagh Basin for the first time. This discovery is also the first record of Cretaceous nautilids from Iran. We identified the specimens as Eutrephoceras clementianum (d’Orbigny 1840), E. sublaevigatum (d’Orbigny 1850), E. bouchardianum (d’Orbigny 1840) and Eutrephoceras sp. These specimens occur in horizons situated between several ammonite-bearing levels, which allowed us to more precisely constrain age estimates for the recovered nautilid specimens. E. clementianum could not be dated precisely but likely comes from between late Aptian ammonite index Hypacanthoplites uhligi and middle Albian Hoplites (Hoplites) baylei. E. sublaevigatum occurs just above the late Albian ammonites Mariella bergeri and Semenoviceras michalskii and below the Mantelliceras mantelli Zone. At the upper part of the section, E. bouchardianum and Eutrephoceras sp. were collected from lower Albian beds, which correspond to the Mantelliceras mantelli and Mantelliceras dixonii zones. These new findings contribute to our knowledge of the geographical distribution and stratigraphic range of Albian–Cenomanian nautilid species.

Late Albian ammonites from the Cauvery Basin, south India

A comprehensive taxonomic account of fourteen ammonite species from the upper Albian succession of the Cauvery Basin, south India is presented. They belong to the genera/subgenera Gaudryceras, Anagaudryceras, Tetragonites, Puzosia (Puzosia), Puzosia (Bhimaites), Desmoceras (Desmoceras), Desmoceras (Pseudouhligella), Stoliczkaia (Stoliczkaia) and the heteromorphs Anisoceras and Mariella. Most of these ammonite species are cosmopolitan and well-known, especially from the western margin of the Tethys. The additional value of this study in contrast to earlier studies is founded in the intensive bed-by-bed collection from a well-documented measured section. This allows to establish a first detailed range chart for the uppermost Albian of this region and to correlate the Cauvery Basin section with the upper Albian Mortoniceras perinflatum Zone-Arrhaphoceras briacensis Zone interval of the Standard Tethyan Scheme.

Late Albian ammonites from Koraćica (Kosmaj Mountain, central Serbia) and their biostratigraphic implications

Nineteen late Albian ammonite taxa and one nautiloid species belonging to eight genera and four families are systematically described from reddish coarse-grained bioclastic packstones to rudstones of the Grab well section (Kosmaj Mountain), Vardar Zone of central Serbia. Among the identified taxa, the nautiloid Eutrephoceras cf. clementianum (d’Orbigny, 1840) and seven ammonite taxa, Tetragonites rectangularis Wiedmann, 1962, Puzosia provincialis (Parona and Bonarelli, 1897), Bhimaites cf. pinguis (Crick, 1907), Beudanticeras (Beudanticeras) cf. beudanti (Brongniart, 1822), Hysteroceras cf. pseudocornutum Spath, 1934, Mortoniceras (Subschloenbachia) rostratum (J. Sowerby, 1817), and M. (S.) cf. perinflatum (Spath, 1922) are recorded for the first time from Serbia. The identified taxa are typical representatives of the Tethyan faunal province. Ammonite taxa provide the first reliable biostratigraphic dating of the Grab well section of central Serbia. The reddish coarse-grained bioclastic packstones to rudstones (a 0.5-m-thick lens) belong to the upper Albian, which is proven by ammonites of the uppermost Albian Mortoniceras rostratum and M. perinflatum zones and the early late Albian brancoceratines Hysteroceras orbignyi (Spath, 1922), H. choffati Spath, 1925, and H. varicosum (J. de C. Sowerby, 1824), which are equivalent to the M. pricei, M. inflatum, and M. fallax zones. The overlying 3.5 m of sandy packstones are assigned to the earliest Cenomanian based on the brachiopods Capillithyris capillata (d’Archiac, 1847) and Terebrirostra lyra (J. Sowerby, 1816), which characterize the lowermost Cenomanian Mantelliceras mantelli Zone. The upper part of the Grab well section (20 m in bedded silty marlstones and marly siltstones) is assigned to lower middle Cenomanian based on the presence of the Turrilites costatus Subzone.

Palynology of the Albian Makhtesh Qatan site, northern Negev (Israel), with descriptions of two new pollen species

Three levels of an independently dated Early Cretaceous succession in the northern Negev have yielded palynofloras of Albian age. The Afropollis jardinus-Tricolpites-Trisectoris-Qatanipollis Assemblage is from the lowermost level, a shale bed of about 60cm thickness intercalated in the predominantly fluvial sandstones of the upper Hatira Formation at Makhtesh Qatan (IQ1 locality). The IQ1 palynoflora is dominated by psilatrilete spores, which are interpreted as influx from a fern bog. Altogether 46 formal and informal taxa were identified among the pteridophytic and bryophytic spores of this locality. The gymnosperms yielded 33 taxa including the new species Partitisporites krassilovii. The angiosperms are represented by 36 mono- and triaperturate species including Afropollis jardinus, the new species Foveomonocolpites ravnii and representatives of the genera Foveotricolpites, Qatanipollis, Rousea, Tricolpites and Trisectoris. A middle Albian age of this assemblage is supported by correlation of the IQ1 level with a marine intercalation, the Uza marine tongue of middle-late Albian age and by the stratigraphic position of the IQ1 bed below the ammonite-dated late Albian lower Hazera (Hevyon) Formation at Makhtesh Ramon.Immediately above the dark grey palyniferous IQ1 shale, grey or light grey shales occur, which are either barren or yielded the remains of a weathered, residual palynoflora with freshwater algae such as Botryococcus and Ovoidites.The upper Hatira Formation discussed so far is overlain by the marine carbonates of the Hazera (=Hevyon Formation). The lower part of this formation yielded at Makhtesh Ramon a late Albian ammonite (Hypengonoceras, Lewy), which is associated with an elaterate pollen-bearing assemblage corresponding largely to the Afropollis jardinus–Elaterosporites klaszii Assemblage recovered by the author from the same formation and locality.In contrast to the spore-dominated IQ1 Assemblage, the late Albian palynoflora from Makhtesh Ramon (Miz7/6) is dominated by Classopollis, followed by psilatrilete spores and dinoflagellate cysts. The IQ1 palynoflora reflects high humidity and influence from a vegetation rich in ferns, while the abundance of Classopollis (Cheirolepidiaceae) in the late Albian sample may suggest a shift towards drier conditions.

Late Albian ammonites from the Aitamir Formation (Koppeh Dagh, northeast Iran)

Late Albian ammonite faunas from the Aitamir Formation of the Koppeh Dagh Basin in northeast Iran are described and illustrated. These comprise 14 taxa, several of which are recorded from Iran for the first time, namely Anahoplites planus (formerly recorded from central Iran in open nomenclature only), Semenoviceras solidus, Epihoplites (Metaclavites) iphitus, Hysteroceras orbignyi and Pseudhelicoceras robertianum. New records of Placenticeras grossouvrei extend the stratigraphic range of this species downwards into the Late Albian; previously it was known from the Early and Middle Cenomanian only. The record of the rare E. (M.) iphitus fills a palaeobiogeographic gap between Crimea and Tajikistan, and the holotype of Spath is re-illustrated here. Additionally, Epihoplites trapezoidalis, from the Late Albian of Tajikistan, is relegated into the synonymy of Spath's species. A large number of taxa typical of the Late Albian (upper part of the Gault Clay Formation) of northwest Europe indicate close palaeobiogeographic affinities with the Koppeh Dagh Basin and faunal exchange across the Russian Platform and Transcaspia. The stratigraphic succession of the ammonite faunas is used for a biostratigraphic subdivision of the upper Aitamir Formation.

Late Albian (Early Cretaceous) ammonites from the Provincial Formation of central Cuba

A late Albian ammonite assemblage from the Provincial Formation of Villa Clara Province, Cuba is described. The Provincial Formation is a lithostratigraphic unit of Albian–Cenomanian age extensively exposed in central Cuba and formed within a part of the Caribbean Tethys that was volcanic during the Cretaceous. The formation is mainly composed of calcareous, terrigenous marine, and volcano-sedimentary deposits characterized by a series of micritic limestones intercalated with marls, sandstones, calcareous conglomerates, ash, and tuffaceous material. A rich assemblage of ammonites recovered from the calcareous biomicrites and marls is of late Albian ( Stoliczkaia dispar Zone, Mortoniceras rostratum Subzone) age. The ammonite fauna shows a strong Tethyan affinity, and only a single hoplitid ammonite species was recorded. Although scarce, the first Cuban report of this and other boreal ammonite species now allows precise correlations to be made between Cuba and Albian sediments elsewhere in the world.

Late Albian ammonites from offshore Suriname: implications for biostratigraphy and palaeobiogeography

Two boreholes (1257A, 1258C) drilled during ODP Leg 207 off the continental margin of Suriname have yielded poorly preserved ammonite fragments and juveniles of early Late Albian age. The assemblage is typically Tethyan and consists of Prohysteroceras sp., an indeterminate engonoceratid (possibly Knemiceras sp.), Parengonoceras sp., Goodhallites sp., Kossmatella sp., Laraiceras sp., Hysteroceras cf. varicosum, H. cf. subbinum, Bhimaites sp., Hamites sp. and Mortoniceras ( Deiradoceras) cf. exile, all of Hysteroceras varicosum Zone age. The preservation of the ammonites suggests the possibility of fish predation. A brief review is presented of the early Late Albian ammonite zonation in the Tethyan province and its application to successions in southern North America, southern South America and around Africa.

Late Middle–early Late Albian ammonites from Ecuador

Ammonites of the Albian genera Brancoceras, Dipoloceras, Mortoniceratoides and Neophlycticeras are described and illustrated for the first time from Ecuador. Precise stratigraphic distribution in the Rio Misahuali field section allows delineation of the Middle/Upper Albian boundary in the Oriente of Ecuador through the recognition of the Dipoloceras cristatum Zone.

Late Albian ammonites from the carbonate cover of the Teloloapan arc volcanic rocks (Guerrero State, Mexico)

In the Guerrero province of Mexico, the calc-alcaline lavas of the Teloloapan volcanic arc unit are overlain by carbonates with reworked neritic faunas of Aptian–Albian age (La Evolucion Geologica y la Metalogénesis del Noroccidente de Guerrero. Universidad Autonoma de Guerrero, Serie Técnico-Cientifica, 1 (1979) 84). The discovery of an ammonite fauna at the top of the Teloloapan limestone provides a latest Albian age assignment for that horizon. The fauna includes: Pervinquieria rostrata, P. gr. inflata, Turrilitoides hugardianus, Stoliczkaia cf. blancheti, S. cf. tenuis, Desmoceras latidorsatum, Oxytropidoceras cf. cantianum, Puzosia aff. mayoriana, Lechites moreti, Hamites cf. gardneri, H. cf. maximus, and Falciferella campae n. sp. A pelagic microfauna is associated with the ammonites and contains Hedbergella sp. and Colomiella recta. The fossiliferous horizon may thus be restricted to the Inflatum and lower Dispar zones. The overlying flysch contains Hamites sp. gr. intermedius near the base. Therefore, volcanism in the Teloloapan arc ceased before the end of the Early Cretaceous, while flysch deposition began in latest Albian times.

Late Albian ammonites from the Northern Territory, Australia

Thirty ammonite taxa are recognised in the Wangarlu Mudstone of the Bathurst Island Group from the Cox Peninsula and Shoal Bay, Northern Territory, Australia. Included are a new heteromorph genus Notostreptites, type species N. exilis, and four additional new species and subspecies: Pseudhelicoceras gracilis, Labeceras (L.) tumidum, Labeceras (Appurdiceras) decorum, and Idiohamites dorsetensis laticostatus. The assemblage is best collectively correlated with the Mortoniceras (M.) inflatum Zone of the standard European Albian zonation but some of its members may represent the lower part of the Stoliczkaia dispar Zone. It is broadly correlative with faunas from the Eromanga Basin, which relate to an extensive eastern Australian Late Albian epicontinental sea, but is strikingly different in aspect. The Wangarlu Mudstone assemblage has relatively high diversity and an abundance of cosmopolitan heteromorph taxa well known from Europe and elsewhere, whereas Eromanga Basin assemblages are of relatively low diver...