Middle Albian Research Articles

Prospects for the Protection of the Stone Heritage of the Małopolska Vistula River Gorge

The aim of this research is to present the abiotic geological environment, morphology and the need to protect geoenvironment and the possibilities of using the geoheritage of mining districts of the region located between Zawichost and Puławy city, within the Geopark. The Geopark is the best example of scientific and educational presentation of Mesozoic and Cenozoic outcrops along the Vistula gorge. The Cretaceous sediments (Middle Albian to Maastrichtian) are especially significant, they are unique on the European scale, showing a record of the evolution of the sea basin - from the Middle Cretaceous transgression and its disappearance at the end of the Cretaceous. The landscape and geomorphological values ​​constituting the heritage of the region are extremely important. An additional circumstance conducive to the creation of the Geopark is the fact that in the area covered by the project, areas of geological heritage protection have been operating for many years and tourist traditions date back to the 18th century.

The Early to Late Cretaceous (Albian–Cenomanian) transition in Putumayo, Colombia: a biostratigraphic and carbon isotope stratigraphic correlation for northwestern South America

Despite the rich geological and paleontological record of Colombia, the Putumayo region near Ecuador remains one of the least explored regions in the equatorial Neotropics, mainly due to its thick vegetation, deep rock weathering, soil formation, and ground cover, geographic remoteness, and inaccessibility of well-exposed outcrops. This has resulted in limited comparisons with neighboring basins and thus the generation of more comprehensive biostratigraphic correlations with western and northern South America, as well as other paleobiogeographic regions (e.g., Tethys, Western Interior Seaway). Here, we present 67 occurrences of uppermost Lower Cretaceous to lowermost Upper Cretaceous ammonoids and other macrofossils (e.g., bivalves, decapod crustaceans, osteichthyan fish remains, plant remains), as well as a δ13Corg chemostratigraphic curve derived from 105 samples from the middle Albian of the uppermost Caballos Formation and the upper Albian to lower Cenomanian lower Villeta Formation, collected in situ from a stratigraphic section exposed along the Mocoa–San Francisco Road, Putumayo, Colombia, here called the San Francisco section. The chemostratigraphic, carbon-isotope curve for the region shows a great similarity with the shape of the accepted curve for the late Albian Oceanic Anoxic Event 1d, which is characterized by a worldwide long positive δ13C excursion anomaly. The new biostratigraphic and isotopic data serve as a point of reference to compare the Putumayo Basin with neighboring basins (e.g., Marañon Basin in Perú, Oriente Basin in Ecuador, Upper Magdalena Valley Basin in Colombia), and thus the generation of more comprehensive upper Lower Cretaceous and lower Upper Cretaceous biostratigraphic and chemostratigraphic correlations for northwestern South America.

Albian sedimentation in western Atlas, Morocco

Detailed study of field sections and extensive ammonite collection allowed to specify the sedimentary evolution and age of the Albian series of the Western Atlas (Morocco). After a significant hiatus of earliest Albian age, the Albian transgression began in the late Douvilleiceras leightonense Zone with partly clastic deposits. A transgressive pulse gave way to clayey marl deposits (Douvilleiceras mammillatum Zone), which evolved upward to partly carbonate, laminated deposits of late early Albian to earliest middle Albian age (Lyelliceras pseudolyelli to early Lyelliceras lyelli zones). A major hiatus that encompassed most of the middle Albian, was followed by a new transgression marked first by sandy deposits (Dipoloceras cristatum and Pervinquiria pricei zones), and then by clayey marl and limestone nodules (Pervinquieria inflata Zone). A sharp sea level fall (late Pervinquieria inflata to early Pervinquieria fallax zones) led to the development of a shallow marine carbonate shelf (Kechoula Formation). A last transgressive pulse allowed deposition of outer shelf clayey marls (Pervinquieria rostrata to Arrhaphoceras briacensis (?) zones), interrupted near the Albian-Cenomanian boundary by a sea level fall and hiatus. Anoxic to disoxic conditions are recorded in the latest early Albian and the late Albian, which correlate with the Leenhardt and Breistroffer levels, respectively. Correlations with Albian successions in North Africa and southern Europe suggest a mainly eustatic origin for the most important sedimentary discontinuities, although the late Albian sea-level drop may be tectonically enhanced.

Comments on « Environmental and climatic controls of the clay mineralogy of Albian deposits in the Paris and Vocontian basins (France) » [Cretaceous Res. 108 (2020) 104342] and « Astronomical calibration of the OAE1b from the Col de Pré-Guittard section (Aptian-Albian) Vocontian Basin » [Cretaceous Res. 150 (2023) 105618

We wish to point out an obvious error made by one of us (J.F. Deconinck), and kindly reported by J.G. Bréhéret, the reason why we have jointly decided to publish this correction. The error affects at varying degrees the scientific quality and partly invalidates the conclusions of the following articles: Corentin et al. (2020) « Environmental and climatic controls of the clay mineralogy of Albian deposits in the Paris and Vocontian basins (France) » (Cretaceous Research, 108). and Ait-Itto et al. (2023) « Astronomical calibration of the OAE1b from the Col de Pré-Guittard section (Aptian–Albian) Vocontian Basin » (Cretaceous Research, 150).Indeed, for the Vocontian basin, the analytical work, whatever its quality, was carried out on a stratigraphic interval which does not correspond to the presentation made. The two articles in question did not take into account the detailed lithostratigraphy and biostratigraphy earlier published, notably by Bréhéret (1997) and Bréhéret & Brumsack (2000) mentioning known marker beds as presented in these works. Thus, for one of the two sections, the displayed time window assumed to be the lower Albian, actually corresponds to a small part of the middle Albian and a part of the upper Albian. This invalidates many of the proposed results and conclusions.

An appraisal of taxonomic issues in Lower to mid-Cretaceous mesorbitolinids (larger benthic foraminifera)

Species differentiation within the genus Mesorbitolina Schroeder 1962 is primarily based on the general structure of the megalospheric embryo and its biometrics. The taxonomy of three taxa, namely Mesorbitolina texana (Roemer 1849), Mesorbitolina subconcava (Leymerie 1878) and Mesorbitolina pervia (Douglass 1960) is complicated due to differing species concepts between authors, and, in the case of the first two named, by missing type designations in the original descriptions as well as disagreements with respect to their type-localities. Herein, it is demonstrated that M. pervia is the junior synonym of Mesorbitolina birmanica (Sahni 1937) due to priority reasons, both taxa characterized by a similar-sized plano-convex protoconch. Some concepts of M. texana and M. subconcava can also be placed in M. birmanica, but not those as defined by lectotypes. Published data for M. birmanica suggest a late Aptian (late Gargasian) to early (? late) Albian age and a cosmopolitan distribution. Mesorbitolina texana appears slightly earlier in the late Aptian persisting into the middle Albian, and a distribution ranging from the southern USA to the Middle East.

A 40 Ar/ 39 Ar and U–Pb timescale for the Cretaceous Western Interior Basin, North America

Abstract Improvements in analytical procedures in parallel with intercalibration of 40 Ar/ 39 Ar and U–Pb methods and laboratories, spurred since 2003 by the EarthTime geochronology community initiative, have led to ±2 σ uncertainties of the order of 50–100 ka, or better, for Cretaceous ash beds. Assembled here are 57 40 Ar/ 39 Ar ages and 17 238 U– 206 Pb ages of volcanic ash beds in strata of the Western Interior Basin of North America determined during the last 15 years since these improvements have been made. These age determinations span from 108 Ma in the middle Albian to 66 Ma in the latest Maastrichtian. Five of the 40 Ar/ 39 Ar ages from Campanian and Maastrichtian strata are newly reported here, whereas the remainder are from the literature. Building on the pioneering work of John Obradovich and Bill Cobban, where possible these age determinations are tied to ammonite and inoceramid biostratigraphy. For most ash beds, the temporal uncertainties, unlike earlier timescales for the Western Interior Basin, are much shorter than the duration of fossil biozones. Proposed ages for stage boundaries based on this review of the radioisotopic ages include: Maastrichtian–Danian, 66.02 ± 0.08 Ma; Campanian–Maastrichtian, 72.20 ± 0.20 Ma; Santonian–Campanian, 84.19 ± 0.38 Ma; Coniacian–Santonian, 86.49 ± 0.44 Ma; Turonian–Coniacian, 89.75 ± 0.38 Ma; Cenomanian–Turonian, 93.95 ± 0.05 Ma; Albian–Cenomanian, 100.00 ± 0.40 Ma. Six bentonites that occur within the Vascoceras diartianum, Neocardiocerus juddi, Prionocylus macombi, Scaphites preventricosus, Scaphites depressus and Desmoscaphites bassleri ammonite zones, dated using both 40 Ar/ 39 Ar and U–Pb methods, yield ages in agreement to within 150 ka and form the backbone of the Western Interior Basin timescale. In parallel, improvements in the taxonomy of ammonites, inoceramids and foraminifera, and recent field work, are better establishing the biostratigraphic framework for these age determinations. Each of these efforts contributes to the progressive refinement of the chronostratigraphic framework of the Western Interior Basin, and enhances its utility for global correlation.

Reconstructing the Iberian Salt‐Bearing Rifted Margin of the Southern Pyrenees: Insights From the Organyà Basin

AbstractReinterpretation of the Organyà Basin, based on new detailed field observations and subsurface data, emphasizes the key contribution of Upper Triassic evaporites in the tectono‐sedimentary evolution of the South‐Central Pyrenees. Results are integrated in a 65‐km long restored cross‐section through the Serres Marginals, Montsec and eastern Organyà salt‐related depocenters. The reconstructed part of the Jurassic–Cretaceous northern Iberian salt‐rich rifted margin shows a template characterized by inherited Permo‐Triassic basement normal faults and an initial salt thickness of 0.7 km to the south and 1.5 km to the north. The Organyà Basin is part of the South Pyrenean Diapiric Province, a large system of salt related depocenters and minibasins, that is limited to the north by the more than 120‐km long Senterada salt wall complex separating the supra‐salt and sub‐salt domains in the Southern Pyrenees. Three main stages of diapiric activity are recognized along the northern Iberian margin from Asturias to the Eastern Pyrenees: a Jurassic early salt mobilization; a latest Jurassic–middle Albian main diapiric evolution associated with rifting; and a Campanian–Miocene diapiric reactivation during basin inversion that produced salt welds and thrust welds and translated the salt province some 60 km to the south.

Upper Barremian−lower Aptian charophyte biostratigraphy from Arrifes section (Algarve Basin, Southern Portugal): correlation with dinoflagellate cyst biostratigraphy

The Arrifes section (Algarve Basin, Southern Portugal) has been studied from the viewpoint of charophyte biostratigraphy. The previous sedimentological studies in this section showed that it is built of the interbedding of continental and marine facies that contain both marine and continental palynomorphs (pollen, spores, and dinoflagellates), providing an excellent sedimentary context to perform direct correlations between marine and continental domains. In the present work, the identified charophyte biozones have been correlated with dinoflagellate biozones previously recognized in the Arrifes section, being the first time that these two biochronologies can be directly correlated. From the charophyte biostratigraphy viewpoint, two assemblages are distinguished. The older one is found between 65 and 135 m of the stratigraphic section, and it is composed of the species Echinochara lazarii, Atopochara trivolvis var. triquetra, A. trivolvis var. trivolvis, Clavator grovesii var. jiuquanensis, Clavator harrisii var. harrisii, C. harrisii var. reyi, and C. harrisii var. zavialensis. This assemblage belongs to the upper Barremian–lower Aptian Clavator grovesii var. jiuquanensis Eurasian biozone and also to the Ascidiellacruciata-Pseudoglobatorpaucibracteatus European biozone and it is described in beds with the dinoflagellate cyst Subtilisphaera scabrata (lower to lowermost upper Barremian) and Odontochitina operculata (from upper Barremian upwards). The younger charophyte assemblage is found between 135 and 155 m of the stratigraphic section, and it is composed of the species A. trivolvis var. trivolvis, Clavator grovesii var. corrugatus, Clavator harrisii var. harrisii, C. harrisii var. reyi, and C. harrisii var. zavialensis. This assemblage belongs to Clavator grovesii var. corrugatus biozone, previously assigned to upper Aptian (Clavator grovesii var. lusitanicus biozone). However, in the Arrifes section, this assemblage is found in beds assigned to the dinoflagellate cyst Odontochitina operculata (from upper Barremian–lower Aptian). The direct correlation of the base of the C. grovesii var. corrugatus biozone with the dinoflagellate cyst O. operculata, indicates that the base of the Clavator grovesii var. corrugatus biozone is in the upper lower Aptian, which is slightly older than was previously suggested, and it is extended until the middle Albian.

A new hermit crab (Anomura, Paguroidea) from the middle Albian of Wissant, Pas-de-Calais (northern France)

A new hermit crab (Anomura, Paguroidea) from the middle Albian of Wissant, Pas-de-Calais (northern France)

A new genus of dance fly (Diptera: Empidoidea: Hybotidae) from Cretaceous Spanish ambers and introduction to the fossiliferous amber outcrop of La Hoya (Castellón Province, Spain).

Hybotidae fly species, also known as dance flies, in Cretaceous ambers have been described from Lebanon, France, Myanmar, Russia, and Canada. Here we describe Grimaldipeza coelica gen. et sp. n., and recognize another two un-named species, in Spanish amber from the middle Albian El Soplao and lower Cenomanian La Hoya outcrops. The fore tibial gland is present in the new genus, which is characteristic of the family Hybotidae. We compare Grimaldipeza coelica gen. et sp. n. with the holotypes of Trichinites cretaceus Hennig, 1970 and Ecommocydromia difficilis Schlüter, 1978, and clarify some morphological details present in the latter two species. Further taxonomic placement beyond family of the here described new genus was not possible and remains incertae sedis within Hybotidae until extant subfamilies are better defined. We provide new paleoecological data of the hybotids, together with paleogeographical and life paleoenvironmental notes. A table with the known Cretaceous Hybotidae is provided. Furthermore, the La Hoya amber-bearing outcrop is described in detail, filling the information gap for this deposit.

Planktonic foraminiferal biostratigraphy and palaeobiogeography of the Albian–Turonian succession from the Sulaiman Range, Pakistan

Detailed taxonomy and biostratigraphy of the limestone, shale‐rich Cretaceous Goru Formation within the western Sulaiman Range refer to diverse and well‐preserved planktonic foraminifera. The age‐diagnostic planktonic foraminifera encountered are; Biticinella breggiensis (middle Albian), Rotalipora ticinensis (late Albian), Rotalipora appenninica (latest Albian), Rotalipora brotzeni (early Cenomanian), Rotalipora cushmani (late Cenomanian), Whiteinella archeocretacea (latest Cenomanian–Earliest Turonian), Helvetoglobotruncana helvetica (early to middle Turonian), and Marginotruncana sigali (late middle to late Turonian). Based on the recovered planktonic foraminifera a middle Albian–late Turonian age has been assigned to the studied formation. The Rotalipora reicheli (middle Cenomanian) Zone was not identified as the First Appearance Datum of the nominal taxa present within the Rotalipora cushmani Zone. The planktonic foraminiferal assemblage characteristics suggest that the bioprovince of the Cretaceous Goru Formation belongs to the subtropical, warm water environment belonging to the Cretaceous Tethyan Realm and the palaeobiogeographic reconstruction suggests that the Neotethys was well‐connected during the Albian–Turonian time interval.

A review of the Cretaceous genus Eltxo (Diptera: Cecidomyiidae) with description of the new species Eltxo grimaldii from El Soplao amber

A new species, Eltxo grimaldii sp. nov., is described from Spanish Lower Cretaceous (middle Albian) amber from El Soplao, based on a single female. The new species is compared with the other only known species of the genus, Eltxo cretaceus Arillo & Nel, 2000, based on a single male specimen also found in Spanish amber, but slightly younger (Peñacerrada I amber; upper Albian). The holotype of E. cretaceus is reviewed and its description corrected and expanded, providing the first micrographs of its anatomical features. The holotype of the new fossil species is the only female specimen known of the cecidomyiid tribe Amediini Jaschhof, 2021, a tribe recently described after changes of taxonomic attribution of the genus Eltxo during the last 20 years.

The Palorbitolinoides event in the Kazhdumi Formation of Southwest Iran and equivalent strata of the Arabian Plate: An expression of the K100 middle Albian transgression

Distinctive beds with abundant large, discoidal specimens of the orbitolinid foraminifera Palorbitolinoides hedini Cherchi and Schroeder are recorded from the Kazhdumi Formation from a section in south-west Iran where ammonite data and associated microfauna suggest a middle Albian age. This taxon, partly previously referred to Orbitolina or high-evolved mesorbitolinids (subconcava-aperta group), has been reported from other sections of the Kazhdumi Formation, the Nahr Umr Formation (Kazhdumi equivalent) of Oman, and the Tisje Formation of northern Somalia. Stratigraphic context and consideration of controlling factors on orbitolinid morphology places these accumulations of flat-discoidal orbitolinids within horizons forming the transgression to the regional Arabian MFS K100 maximum flooding sensu Sharland et al. (2001). These Palorbitolinoides limestones thus form useful marker beds assisting in regional correlation and age calibration. These records also confidently extend the range of P. hedini into younger Albian strata than previously recognised by most authors.

Astronomical calibration of the latest Aptian to middle Albian in the South Atlantic Ocean

Carbon cycle perturbations dramatically affected the ocean-climate system during the Aptian–Albian transition. However, the chronology of this interval is still intensively debated. Here we present a comprehensive astronomical calibration of planktonic foraminiferal and calcareous nannofossil bioevents along a complete marine sedimentary succession, comprising the latest Aptian to middle Albian interval at drilling Core SER-03, located in the Sergipe-Alagoas Basin. The SER-03 astrochronology is based on the tuning of a high-resolution gamma ray (GR) record to the long eccentricity (405 kyr) metronome, and is integrated with high-resolution paleomagnetic records. Our results span the interval between ~114.7 and 109.5 Ma, within magnetochron C34n, and our age estimates for biostratigraphic markers agree within one long eccentricity cycle with previous estimates. We also present geochemical records, such as stable carbon isotopes (δ13C), organic carbon and carbonate contents, as well as redox-sensitive elemental ratios, measured on bulk sediments at Core SER-03. Most of these proxy records depict marked changes across the Aptian–Albian boundary, likely characterizing the local expression of Oceanic Anoxic Event 1b (OAE 1b), filling the gap for low-latitude records of this event.

The late Aptian–early Albian transgressions in the Chott area, southern Central Tunisia

The detailed sedimentological and biostratigraphic study of the upper Aptian–Albian series in the Chott area, southern Central Tunisia, leads to the identification of several, well-dated depositional sequences. The upper Aptian sequences are marked by very shallow marine, first partly evaporitic, then mainly clastic deposits. The last sequence yielded latest Aptian ammonites (H. jacobi zone). The Aptian–Albian boundary is assumed to be marked by a long-lasting hiatus, and by the abrupt change from clastic to carbonate deposits. The overlying “Knemiceras Beds” express the Albian transgression, and comprise four depositional sequences. New findings of ammonites allow to date these beds to the lower Albian (D. mammillatum superzone), and to correlate the four sequences with those defined in Central Tunisia. Five distinct morphologies of Knemiceras sp. are recognized in the “Knemiceras beds”. Because of their stratigraphic position, the overlying massive shelf carbonates (Radhouane Member) are ascribed to the uppermost lower Albian (T. camatteanum and L. pseudolyelli zones), and correlated with the Allam Limestone of Central Tunisia. This carbonate series is capped by a major discontinuity, correlated with the middle Albian discontinuity known in Central Tunisia. The ammonites and rudists fauna are presented and illustrated.

Taxonomy and phylogeny of Albian-Maastrichtian planispiral planktonic foraminifera traditionally assigned to Globigerinelloides

We propose a considerably revised taxonomy and phylogeny for Albian-Maastrichtian planispiral planktonic foraminiferal species that have traditionally been included in Globigerinelloides. The revised taxonomy is necessary because of a ~6 m.y. gap between the extinction of planispiral species during the late Aptian and the next younger occurrence of planispiral species in the middle Albian. Our stratophenetic taxonomic groupings utilize ontogenetic morphometric data, shell wall ultrastructure, and general morphologic features observed from Scanning Electron Microscope and X-radiograph images of primary type specimens and globally distributed hypotype specimens. The planispiral lineage Laeviella n. gen., whose type species is La. bentonensis (Morrow), first appeared in the middle Albian and is postulated to have evolved from the evolutionary series Ticinella primula Luterbacher-Laviella primuloides n. sp. Laeviella is characterized as having a smooth to finely pustulose wall texture and a moderate chamber size increase rate. Two additional species, La. tururensis (Bronnimann) and La. bollii (Pessagno), are included in Laeviella with the youngest species of the genus, La. bollii, becoming extinct during the late Campanian. Planohedbergella, with Plh. aspera (Ehrenberg) as its type species, is revised to include 10 species that show a wide variation in chamber arrangement, wall microstructure and test morphology, but all have a moderately to coarsely pustulose wall texture on some or most final whorl chambers. Its stratigraphic range is from the late Albian-Cretaceous/Paleogene boundary. The oldest species is Plh. ultramicra (Subbotina), which evolved from Planomalina pulchella Todd and Low during the late Albian. Planohedbergella circularis n. sp. is described as a new late Campanian-Maastrichtian species representing forms with evolute coiling, a large number of final whorl chambers, and a slow chamber size increase rate. Polycamerella n. gen. is described as a monospecific genus, with Po. tardata n. sp. as the type species. It is a small, biapertural form with a very slow chamber expansion rate and a stratigraphic range from the late Campanian-Maastrichtian. The ancestor of Po. tardata, is tentatively identified as Plh. ultramicra.

Scleractinian corals of the Albian (uppermost Lower Cretaceous)—overview, revision, evaluation

In the current study, scleractinian corals from the Albian (uppermost Lower Cretaceous; 112.6–99.7 Ma) including 337 species (280 taxa assigned to species; 57 taxa kept in open nomenclature) from 147 genera (six of which include subgenera) belonging to 42 families (two of which include subfamilies; and incertae sedis) are evaluated and revised. Two new species (Apoplacophyllia asiatica, new species and Trigerastraea sikharulidzeae, new species) are described and two lectotypes are designated. Some specimens are illustrated for the first time, and new material (from Austria) is presented. The coral material includes records from 30 regions in Africa, the Americas, the Arctic, Asia, Australasia, and Europe. The most extensive records of Albian corals are from tropical/subtropical and arid areas, including the U.S.A., Mexico, Greece, France, and Spain. Over three-quarters of the Albian taxa belong to morphological forms having little to no hermatypic character (sensu Coates & Oliver), including species of the cerioid-plocoid group (genera: 36.7%; species: 38.5%), solitary taxa (genera: 26.5%; species: 28%), and branching forms (genera: 26.5%; 39 species = 11.5%). The coral faunas of the Albian are dominated by corals of “modern” microstructural groups sensu Roniewicz & Morycowa (76 genera = 51.7%; 169 species = 50.1%). Compared to the lowermost Cretaceous (Berriasian), which showed that 91% of the species and 83% of the genera belonged to previously established microstructural groups, the Lower Cretaceous ends with “modern” groups having become dominant. During the lower and middle Albian, the vast majority of taxa belonged to colonial forms (both 74%). A shift took place during the upper Albian, significantly increasing the number of solitary species to over 40% of the Albian fauna (42.9%). Throughout the Albian, the most diverse coral assemblages include non-reefal faunas, suggesting that, in contrast to, e.g., the Barremian–Aptian time period, reefal developments were less crucial for coral recruitment during this time. This study of the Albian fauna was used as the basis for synthesizing classical taxonomic works with modern microstructural data and recent DNA analyses in order to propose both a modified taxonomic framework and a working hypothetical phylogenetic tree for 41 scleractinian families occurring in the fossil record.

New biostratigraphic observations of planktonic foraminifera and ammonites on the Aptian–Albian intrashelf succession, Zagros Basin, SW Iran

A detailed planktonic foraminiferal biostratigraphic framework, associated with supporting ammonite data, is presented for Aptian–Albian intrashelf sedimentary succession (Kazhdumi Formation) at the Tang-e-Maghar section, Zagros Basin, SW Iran. Most of the identified planktonic foraminiferal species are reported for the first time from this region, and the fauna permits five biozones to be newly proposed from the upper Aptian Globigerinelloides aptiensis Zone to the middle Albian Ticinella primula Zone. Notably, we recognize a narrow interval of faunal turnover in the Microhedbergella miniglobularis Zone, the base of which is delimited by the highest occurrences of Aptian-representing taxa and the top by the lowest occurrence of the Albian Microhedbergella praeplanispira. The proposed Aptian/Albian boundary should lie within this interval accordingly. In addition, we report on 12 ammonite levels that can be used to constrain the Aptian–Albian Substages. The proposed planktonic foraminiferal biozonation of the studied section will be an important step toward better understanding of the nature of the biotic and global changes across the Aptian/Albian boundary on the Arabian Plate in the paleotropical southern Neo-Tethys.

The Permian to Cretaceous succession at Permpasset, Wollaston Forland: the northernmost Permian and Triassic in North–East Greenland

Permian to Triassic outcrops in East Greenland diminish significantly northwards. Understanding the northward extent, and nature, of the Permian and Triassic successions has implications for regional palaeogeographic reconstructions and exploration in adjacent offshore basins. Examining the structural relationships between the basement, Permian, Triassic, Jurassic and Cretaceous successions can further our understanding of the tectonic evolution of the region. Here, we describe a hitherto overlooked section through the Permian to Cretaceous from central Wollaston Forland and consider its structural context. The western side of Permpasset forms the upthrown eroded crest of a horst block, which provides exposure of the earliest stratigraphic intervals in the region. The fractured Caledonian basement is overlain by evaporitic marine limestone facies of the Karstryggen Formation, which are succeeded by shallow marine sandstones assigned to the Schuchert Dal Formation, both Upper Permian. The overlying unit records a period of fluvial deposition and is not possible to date. However, an Early to Middle Triassic age (Pingo Dal Group) seems most likely, given regional eustatic considerations. This is, therefore, the most northerly record of Triassic strata in North–East Greenland. West of the horst structure, fine-grained sandstones and bioturbated siltstones of the Jurassic (Oxfordian) Jakobsstigen Formation are recorded. These were downfaulted prior to a prolonged hiatus after which both the Triassic and Jurassic strata were draped by Cretaceous shales of the Fosdalen Formation. The Cretaceous succession is overlain by a thick basalt pile of Eocene age, heralding the opening of the North-East Atlantic. Glendonites overlie Oxfordian siltstones at the base of the middle Albian Fosdalen Formation. These were likely winnowed from slightly older Cretaceous strata and overlie the hiatus surface between the Jurassic and Cretaceous. This is the first record of glendonites from the Cretaceous of East Greenland and they are interpreted to record the Circum–Arctic late Aptian – early Albian cooling event.

Record of the Middle Albian (Lower Cretaceous) ammonoids from the Cauvery Basin, southern India

ABSTRACT The two Middle Albian index ammonoid species Hamites (Hamites) attenuatus and Hamites (Hamites) rectus are recorded for the first time from the Karai Formation in the Ariyalur Sub-basin of the Cauvery Basin. The part of succession under the present endeavour has yielded eight ammonoid specimens from four ammonoid levels which are systematically described in the Cauvery Basin. Biostratigraphic evaluation of these ammonoids enables the authors to formulate Hamites (Hamites) attenuatus Zone which is broadly correlatable to the Hoplites dentatus Zone – Euhoplites lautus Zone interval of the standard ammonoid zonal scheme.