Campanian Boundary Research Articles

Carbon isotopes, palynology and stratigraphy of the Santonian–Campanian boundary: The GSSP auxiliary sections, Seaford Head (England) and Bocieniec (Poland), and correlation between the Boreal and Tethyan realms

The stratigraphy and palynology of the upper Santonian–lower Campanian (Uintacrinus socialis–Gonioteuthis quadrata zones) Newhaven Chalk are described for the Campanian auxiliary GSSP section at Seaford Head, England. A new high-resolution bulk-sediment carbonate carbon stable-isotope (δ13Ccarb) curve provides the basis to refine the carbon-isotope event (CIE) stratigraphy of the section. Results are compared to a complementary palynological study of a second Campanian auxiliary GSSP section (U. socialis–O. pilula zones) at Bocieniec, Poland. Palynological assemblages are dominated by organic-walled dinoflagellate cysts (dinocysts; 208 taxa) at both sites. A stratigraphic framework is established via review of published lithostratigraphic, macrofossil, foraminifera and calcareous nannofossil records from the study sites. Carbon isotope curves with 13 major named CIEs provide a basis for correlation of Seaford Head and Bocieniec to sections at: Trunch, England; Poigny, France; Lägerdorf, Germany; and the Campanian GSSP at Gubbio, Italy. Correlations are constrained by biostratigraphic records, including dinocyst events. The Late Santonian δ13C Event (LSE, previously termed the Santonian–Campanian Boundary Event, SCBE) provides a key correlation level between Boreal and Tethyan sections and enables the placement of base Campanian markers: extinction levels of the crinoid Marsupites and the planktonic foraminifera Dicarinella asymetrica; the first appearance of the calcareous nannofossil Aspidolithus parcus parcus; and the C34n/C33r magnetozone boundary (the primary Campanian marker), in both Boreal and Tethyan sections. A holostratigraphy for the Santonian–Campanian boundary interval that integrates CIEs, macrofossils, benthic and planktonic foraminifera, calcareous nannofossils, dinocysts and magnetostratigraphy is presented. Rhynchodiniopsis juneae sp. nov. is described.

Organic matter accumulations in the Santonian-Campanian (Upper Cretaceous) lacustrine Nenjiang shale (K2n) in the Songliao Basin, NE China: Terrestrial responses to OAE3?

The local and/or global environmental effects on the organic matter (OM) enrichment in ancient sediments has long received extensive attention. The Upper Cretaceous Nenjiang lacustrine shale (K2n) is one of the most essential hydrocarbon source rocks in NE China with massive OM deposition across the Santonian–Campanian boundary interval, which can be correlated with the terminal stage of the last oceanic anoxic event in the Cretaceous, OAE3. This study focuses on the lower part of the Nenjiang Formation from drill core A-1 in the Songliao Basin paleo-lake system, and highlights two episodes of enhanced OM accumulation controlled by distinct mechanisms. During the first episode in Member 1 of K2n (K2n1), total organic carbon (TOC) values reach a maximum of ~8.0% but fluctuate rapidly. The second episode occurs at the base of the Member 2 of K2n (K2n2) and is associated with a more transient and rapid OM enrichment event exhibited as a single-peak TOC pulse (maximum ~13%). Inorganic and organic geochemical indicators consistently show that two OM accumulation episodes are controlled by different environmental backgrounds: (1) the pristane/phytane values, homohopane index, and the distribution of the redox-sensitive elements suggest that the oxygen content of the bottom water during the K2n1 was relatively lower with transient euxinia (anoxic and sulfidic water column); (2) the paleoproductivity and OM source indicators illustrated that marine-sourced OM occurred during K2n1, whereas terrestrial paleoproductivity had a greater impact on the OM accumulation during K2n2; (3) the water connectivity indicators demonstrate strong periodic seawater incursions during the K2n1, yet the environment during the early stage of K2n2 is more restricted and the paleolake was dominated by fresh-water. It is also underscored that terrestrial envi ronments might be more sensitive to climatic perturbations associated with OAEs. The rapid sea-level (lake-level) variations possibly controlled the distinct OM types and accumulation mechanisms and resulted in different OM accumulation patterns in the lower part of the K2n during the Santonian–Campanian. The widely distributed OM-rich sediments of the K2n in the Songliao Basin indicate that the enhanced burial of OM in terrestrial environment, along with similar coeval OM-rich deposits worldwide, can create important negative feedbacks to changes in the global exogenic carbon cycle possibly contributing to OAE3.

Bio-, Chemo-, and Magnetostratigraphy of the Santonian–Campanian Boundary in the Kudrino and Aksu-Dere Sections (Southwestern Crimea): Problems of Global Correlation and Selection of the Lower Boundary Stratotype of the Campanian. 2. Magneto- and Chemostratigraphy, Discussion

Bio-, Chemo-, and Magnetostratigraphy of the Santonian–Campanian Boundary in the Kudrino and Aksu-Dere Sections (Southwestern Crimea): Problems of Global Correlation and Selection of the Lower Boundary Stratotype of the Campanian. 2. Magneto- and Chemostratigraphy, Discussion

New Bio-, Chemo-, and Magnetostratigraphy of the Santonian–Campanian Boundary in the Kudrino and Aksu-Dere Sections (SW Crimea): Problems of Global Correlation and Selection of the Lower Boundary Stratotype of the Campanian. 1. Geological Framework, Sedimentology, Biostratigraphy

New Bio-, Chemo-, and Magnetostratigraphy of the Santonian–Campanian Boundary in the Kudrino and Aksu-Dere Sections (SW Crimea): Problems of Global Correlation and Selection of the Lower Boundary Stratotype of the Campanian. 1. Geological Framework, Sedimentology, Biostratigraphy

Calcareous nannofossils and other proxies define the Santonian–Campanian boundary in the Central Crimean Mountains (Alan-Kyr section)

The taxonomic composition and detailed stratigraphic distribution of the calcareous nannofossils from the Santonian and Campanian of the Crimea have been studied for the first time. The identified assemblage of calcareous nannofossils in the Alan-Kyr section consists of 85 species, including all primary and additional zonal markers. The following calcareous nannofossil zones and subzones have been recognised and correlated with planktonic (PF) and benthic (BF) foraminifera zones: transitional Santonian–Campanian CC17 or latest Santonian UC13 (Dicarinella asymetrica/D. concavata PFZone and the lower part of Globotruncanita elevata/stuartiformis PFZone), lower Campanian CC18a/UC14a, CC18b–c and CC19/UC14b–UC15a (Globotruncanita elevata/stuartiformis PFZone), lower Campanian CC20/UC15b (Contusotruncana plummerae/Globotruncana ventricosa PFZone), upper Campanian CC21/UC15c (Contusotruncana plummerae/Globotruncana ventricosa PFZone and Globotruncanella havanensis PFZone) and upper Campanian CC22/UC15d (Globotruncanella havanensis PFZone). Using magnetostratigraphic data as the primary source for definition of the base of the Campanian, we place the Santonian–Campanian boundary in the Alan-Kyr section at the level of the base of Chron C33r and inside the nannofossil transitional Santonian–Campanian CC17 or lower Campanian UC14 Zone and the planktonic foraminifera Santonian D. asymetrica/D. concavata Zone. This conclusion is supported by the relative position of other microfossil bioevents: the first occurrence of Broinsonia parca parca, which happens just above the highest occurrences of both Dicarinella asymetrica and D. concavata, as well as the lowest occurrence of the benthic foraminifera Neoflabellina asema.

Campanian carbon isotope calibrated paleofertility estimates from northwestern Tunisia: Inferences from calcareous nannofossils

Abstract The δ13C calibrated Campanian (upper part of CC17/UC13 to CC23a/UC16 zones) calcareous nannofossil assemblages were analyzed to reconstruct paleofertility, paleoenvironment, and sea–level changes from the Jebil section, north–western Tunisia. Seven globally–recognized δ13C events are noted: three positive [Santonian–Campanian Boundary Event (SCBE); Early–Campanian Event (ECE); Mid–Campanian Event (MCaE)] and four negative excursions (Pillula Event; Conica Event; Late–Campanian Event (LCE); Epsilon Event or the C1– Event). The nannofossil assemblage is dominated by Watznaueria barnesae (28%), Lucianorhabdus cayeuxii (8%), Micula decussata (6%), Cyclagelosphaera reinhardtii (5%) and Micula concava (4%). In spite of the dominance of W. barnesiae (range: 33–46.5%), the signal given by the nannofossil assemblage is primary. All species–based proxies (the percentage abundances of stressed/opportunistic taxa, high and low fertility taxa, cool and warm watermass taxa, and Nannoconus spp.) along with the inferred Paleotemperature Index, suggests a cooling trend for the Campanian. Data suggests that oligotrophy was a greater influencing factor than paleotemperature, for the observed changes within the nannofossil assemblage. As a result of this extreme oligotrophy, a distinct assemblage is recorded that is marked by the absence of Biscutum, reduced % abundances of Prediscosphaera (0.7%), Retecapsa (2.3%), and Zeugrhabdotus (1.8%), but with the dominance of W. barnesiae.

Calcareous nannofossil biostratigraphy and bio-events of the Coniacian–lower Campanian succession in the Kurdistan region, northeastern Iraq

The calcareous nannofossil biostratigraphy and bio-events of the Coniacian–lower Campanian succession are examined from the Dokan section, northeastern Iraq, along the southern Tethyan margin. In the Dokan section, calcareous nannofossils are affected by dissolution and silicification. The vertical stratigraphic distribution of calcareous nannoplankton allows identifying eight nannofossil zones (CC13/UC9 to CC20/UC15b). These calcareous nannofossil zones are correlated with planktonic foraminiferal biozones. Calcareous nannofossils calibrated by planktonic foraminiferal biozones suggest that (1) the Turonian–Coniacian boundary can be approximately delineated within the Marthasterites furcatus (CC13) Zone and the base of the planktonic foraminiferal Dicarinella concavata Zone, (2) the Coniacian–Santonian boundary can be delineated at the base of the nannofossil Zone CC16 and close to the base of the D. asymetrica Zone, and (3) the Santonian–Campanian boundary can be located approximately in the uppermost part of the nannofossil Zone CC17 and near the uppermost part of the planktonic foraminifera D. asymetrica Zone.

The Santonian–Campanian Boundary Event (SCBE) in Boreal Basins: New geochemical and mineralogical data from the Northern Chalk Province (East Yorkshire, UK)

The Upper Cretaceous Flamborough Chalk Formation of the English Northern Chalk Province (Danes Dyke section, East Yorkshire, UK) has been sampled for isotope analyses to test for the expression of the positive carbon-isotope excursion defining the Santonian–Campanian Boundary Event (SCBE) in northern England, and to improve basin-scale correlations between the Boreal and Tethyan realms. Clay mineral investigations have been conducted in order to characterise potential variations in the detrital flux between the top of the Santonian and the base of the Campanian, and to test relationships with the SCBE. In the Flamborough Chalk and in other chalk sections, the Santonian/Campanian boundary is defined by the highest occurrence datum of the crinoid Marsupites. Carbon isotope results in this section indicate the presence of the negative Foreness Event in the upper Santonian, while the SCBE is characterised by a double positive excursion with peaks respectively named ‘a’ and ‘b’. The first peak of the SCBE (a) lies in the uppermost part of the Marsupites Zone and therefore belongs to the upper Santonian. Peak b of the SCBE is located above the highest occurrence of Marsupites and is thus partially included in the Uintacrinus anglicus Zone of the lower Campanian. The clay fraction (<2 μm) analysis of chalks and marl bands reveals dominant smectite-rich clay minerals (e.g. R0 type illite/smectite mixed-layers or IS R0, 95% on average) and subordinate illite (5% on average) through the section. A discrete increase of the illite/IS R0 ratio in the clay fraction, combined with an increase in marl horizons and clay proportions in the bulk insoluble residue, highlight slightly enhanced terrigenous input during the SCBE. Correlation with published key sections in Western Europe shows that the SCBE has a similar chemostratigraphic signature and can be used to refine regional correlations, although it is thicker in the English Northern Province due to higher sedimentation rates in this area.

The Santonian – Campanian boundary and the end of the Long Cretaceous Normal Polarity-Chron: Isotope and plankton stratigraphy of a pelagic reference section in the NW Tethys (Austria)

The base of the Campanian still lacks a designated primary marker and a defined GSSP (Global Boundary Stratotype Section and Point). We present a Santonian–Campanian boundary section from the Postalm in the Northern Calcareous Alps of Austria as a possible reference section for the northwestern Tethys. Including nearby complementary Gosau Group sections, the stratigraphy for this time interval is based on palaeomagnetic and stable isotope data, planktonic foraminifera and calcareous nannoplankton bio-stratigraphy, and strontium isotope stratigraphy, together with published ammonite, crinoid and inoceramid data. The Postalm section shows a deepening trend from upper Santonian conglomerates and grey shelf marls to pelagic bathyal red marly limestones of mainly Campanian age. Palaeomagnetic data allow identifying the top of the Long Cretaceous Normal Polarity-Chron C34n and the following reversal in the lower part of the red marly limestones. A 1 m-thick interval of high magnetic susceptibility is present at the end of C34n. Two of the main suggested biomarkers to pinpoint the Santonian–Campanian boundary, i. e. the last occurrence of the planktonic foraminifer Dicarinella asymetrica and the first occurrence of the nannofossil Broinsonia parca parca, occur in close proximity above the reversal, which is suggested herein as the main marker event for the base of the Campanian. Strontium isotope stratigraphy indicates a value of 0.707534 (mean of four measurements at the boundary interval) for the base of the Campanian in the Postalm section. Both carbon and oxygen isotope values show a negative excursion just below the boundary. The positive Santonian–Campanian carbon isotope event starts probably just below the reversal but seems to be diagenetically distorted. This interval is considered to correspond to a short sea-level high in the late Santonian followed by a distinct lowstand at the Santonian–Campanian boundary.

A New Southern North Atlantic Isochron Map: Insights Into the Drift of the Iberian Plate Since the Late Cretaceous

AbstractThis paper presents a new southern North Atlantic plate model from Late Cretaceous to present, with the aim of constraining the kinematics of the Iberian plate during the last 83.5 Myr. This model is presented along with a detailed isochron map generated through the analysis of 3 aeromagnetic tracks and ~400 ship tracks from the National Centers for Environmental Information database. We present a new technique to obtain well‐constrained estimates of the Iberia‐North America plate motions from magnetic anomalies, overcoming the scarcity of large‐offset fracture zones and transform faults. We build an integrated kinematic model for NW Africa, Morocco, Iberia, Europe, and North America, which shows that the deformation is partitioned between Pyrenees and Betic‐Rif orogenic domain during the Late Cretaceous‐Oligocene time interval. In the Eastern Betics domain, the calculated amount of NW Africa‐Iberia convergence is ~80 km between 83.5 and 34 Ma, followed by ~150 km since the Oligocene. The motion of Iberia relative to Europe in the Central Pyrenees is characterized by overall NE directed transpressional motion during the Campanian and the Paleocene, followed by NW directed transpressional movement until the Lutetian and overall NNW directed convergence from Bartonian to Chattian. This motion occurs along the axis of the Bay of Biscay from the Santonian–Campanian boundary to the middle Priabonian, subsequently jumping to King's Trough at Anomaly 17 (36.62 Ma).

An integrated stratigraphic study across the Santonian/Campanian boundary at Bocieniec, southern Poland: A new boundary stratotype candidate

An integrated biostratigraphic (foraminifera, calcareous nannofossils, crinoids), chemostratigraphic (stable carbon isotopes) and magnetostratigraphic study of the Bocieniec section (southern Poland) is presented here. The section presents a continuous and lithologically monotonous sedimentary record across the Santonian–Campanian boundary transition. A large number of macrofossil, foraminiferal and calcareous nannofossil bioevents along with several well-identified carbon-isotope excursions of the upper Santonian and lowermost Campanian are documented. The base of the Campanian is well-constrained by the last occurrence (LO) of the crinoid Marsupites testudinarius, and correlates to the onset of the first δ13C positive peak of the Santonian–Campanian Boundary Event (SCBE peak a). A presumable primary Cretaceous paleomagnetic signal highlights the potential presence of the C34N/C33R magnetic reversal although its exact position remains uncertain between peaks a and b of the SCBE. The planktic foraminifer Dicarinella asymetrica is very rare at Bocieniec but a potential LO of this important marker may be recorded in coincidence with peak b of the SCBE. The first occurrence (FO) of calcareous nannofossil Broinsonia parca parca coincides with the lower part of chron C33R and with the early Campanian pilula zone event. A large set of additional nannofossil events and benthic foraminifer events further constrain the stratigraphy of the section and along with the carbon isotopes, allows for correlation with other important sections of the Boreal realm. Although the Bocieniec section is relatively thin and condensed (5.5 m), the successive order of events and presence of all past proposed stratigraphic criteria for the Santonian-Campanian boundary makes it the most complete reference section for this interval at the European and at the global scale. Moreover, this section allows for a precise correlation of the Tethyan and Boreal domains. The Bocieniec section fulfils the geological criteria to be a potential boundary stratotype candidate for the base of the Campanian Stage.

Plankton biostratigraphy and magnetostratigraphy of the Santonian–Campanian boundary interval in the Mudurnu–Göynük Basin, northwestern Turkey

The Santonian–Campanian boundary interval close to the village of Göynük in northwestern Turkey (Bolu province) was recorded and examined with respect to nannofossil and foraminiferal biostratigraphy, magnetic polarity and magnetic susceptibility. During the Late Cretaceous, the Mudurnu–Göynük Basin was located on the Sakarya continent situated in the northwestern Tethyan Realm, north of the Neo-Tethys.The sections assessed for the present study comprise hemipelagic to pelagic deposits. Five localities were examined and a composite record spanning the Santonian–Campanian boundary was established. The stratigraphically older parts are characterised by uniform reddish limestone, while we frequently recorded shaly marls and marly limestones with recurrent tuff intercalations in the younger subsections.A biostratigraphic investigation of planktonic foraminifera and calcareous nannoplankton assemblages, together with magnetostratigraphy, provides a stratigraphic framework that allows to home in on the Santonian–Campanian boundary. Thus, biostratigraphic data suggest an age that ranges from the late Santonian Dicarinella asymetrica to the early Campanian Globotruncanita elevata planktonic foraminifera biozones, and calcareous nannofossil zones UC12–UC14 and CC16–CC18. The magnetostratigraphic assessment finds a palaeomagnetic reversal that can be recognised as the basal Campanian reversal C33r above polarity chron 34n, the Long Cretaceous Normal.Field magnetic susceptibility (MS) data show a distinct cyclic pattern in the lower Campanian. Sinusoidal patterns in the MS signature curve can presumably be interpreted as the 400 kyr orbital eccentricity cycle, and subsequent smaller-scale cycles of obliquity and precession can be identified even though volcanic activity impacted sedimentation. A sediment accumulation rate of 12 mm/kyr can be inferred for one of the sections.

The crinoid Marsupites in the Upper Cretaceous Nanaimo Group, British Columbia: Resolution of the Santonian–Campanian boundary in the North Pacific Province

The strongly endemic nature of Late Cretaceous molluscan faunas of the North Pacific region creates challenges for correlation of stratigraphic sections in basins surrounding the proto-Pacific Ocean with European standard successions. A particularly problematic stage boundary in the Pacific region is the Santonian–Campanian boundary, which is poorly defined in the northwest and northeast Pacific regions on the basis of local ammonite and inoceramid bivalve assemblages or poorly constrained magnetostratigraphy. Examples of the crinoid genus Marsupites Mantell in Miller 1821, considered a marker of the Santonian–Campanian boundary at many places around the globe, have been collected recently from a number of localities of the Upper Cretaceous Nanaimo Group succession of southwestern British Columbia, including the species M. testudinarius and M. lamberti. Co-occurring specimens of Marsupites testudinarius in the Nanaimo Group include both smooth and coarsely ornamented forms which do not show stratigraphic segregation, suggesting that M. testudinarius is a morphologically-variable species which includes forms that were attributed to different species by previous workers. The presence of M. testudinarius in stratigraphic sections of the Nanaimo Group allows the precise placement of the Santonian–Campanian boundary interval in the Nanaimo Group succession, and correlation of this boundary with the European standard succession. As well, the occurrence of the crinoid allows for revision of the biostratigraphic zonation of the upper Santonian–lower Campanian interval in the Nanaimo Group. Characteristic molluscan assemblages which are found in association with M. testudinarius in the Nanaimo Group are known to occur elsewhere along the North American Pacific slope (e.g., northern California, USA), as well as in the northwest Pacific region (Japan, Sakhalin, Koryakia), and thus provide a marker for the Santonian–Campanian boundary in those areas where Marsupites has not yet been found.

Radiolarians, foraminifers, and biostratigraphy of the Coniacian–Campanian deposits of the Alan-Kyr Section, Crimean Mountains

Data on the distribution of radiolarians and planktonic and benthic foraminifers are obtained for the first time from the Alan-Kyr Section (Coniacian–Campanian), in the central regions of the Crimean Mountains. Radiolarian biostrata, previously established from Ak-Kaya Mountain (central regions of the Crimean Mountains) were traced: Alievium praegallowayi–Crucella plana (upper Coniacian–lower Santonian), Alievium gallowayi–Crucella espartoensis (upper Santonian without the topmost part), and Dictyocephalus (Dictyocryphalus) (?) legumen–Spongosaturninus parvulus (upper part of the upper Santonian). Radiolarians from the Santonian–Campanian boundary beds of the Crimean Mountains are studied for the first time, and Prunobrachium sp. ex gr. crassum–Diacanthocapsa acanthica Beds (uppermost Santonian–lower Campanian) are recognized. Bolivinoides strigillatus Beds (upper Santonian) and Stensioeina pommerana–Anomalinoides (?) insignis Beds (upper part of the upper Santonian–lower part of the lower Campanian) are recognized. Eouvigerina aspera denticulocarinata Beds (middle and upper parts of the lower Campanian) and Angulogavelinella gracilis Beds (upper part of the upper Campanian are recognized on the basis of benthic foraminifers. These beds correspond to the synchronous biostrata of the East European Platform and Mangyshlak. Marginotruncana coronata-Concavatotruncana concavata Beds (Coniacian–upper Santonian), Globotruncanita elevata Beds (terminal Santonian), and Globotruncana arca Beds (lower Campanian) are recognized on the basis of planktonic foraminifers. Radiolarian and planktonic and benthic foraminiferal data agree with one another. The position of the Santonian–Campanian boundary in the Alan-Kyr Section, which is located stratigraphically above the levels of the latest occurrence of Concavatotruncana concavata and representatives of the genus Marginotruncana, is refined, i.e., at the level of the first appearance of Globotruncana arca. A gap in the Middle Campanian–lower part of the upper Campanian is established on the basis of planktonic and benthic foraminifers. The Santonian–Campanian beds of the Alan-Kyr Section, on the basis of planktonic foraminifers and radiolarians, positively correlate with synchronous beds of the Crimean-Caucasian region, and beyond. Benthic foraminifers suggest a connection with the basins of the East European Platform.

Cenomanian–Campanian (Late Cretaceous) planktonic assemblages of the Crimea–Caucasus area: Palaeoceanography, palaeoclimate and sea level changes

During the Cretaceous, the Crimea–Caucasus area occupied a position in the Peri-Tethys which was transitional between the Boreal and Tethyan realms. The evolution and stratigraphic distribution of planktonic foraminifera and radiolarians in the Upper Cretaceous sediments of the region are described. The specialized, morphologically complex keeled taxa evolved in the latest Albian and persisted until the end of the Cretaceous. These overall evolutionary trends are punctuated by a series of bioevents, one of the most important being the Cenomanian–Turonian boundary. This is marked by a series of organic-rich sediments, that are related to an Oceanic Anoxic Event. The Turonian–Coniacian interval was marked by a further development of keeled taxa. A major change in the assemblage is described near the Santonian–Campanian boundary, when marginotruncanids were replaced by globotruncanids.The Albian is marked by the diversification of the radiolarian genus Crolanium, the last occurrence of which is typical of the Albian–Cenomanian boundary. The Upper Coniacian to Lower Santonian strata are characterized by the high taxonomic diversity of the Quinquecapsulariidae and the Neosciadiocapsidae. A marked change in the radiolarian assemblage occurred at the Santonian–Campanian boundary: the Late Santonian, warmer-water assemblage dominated by the Pseudoaulophacidae being replaced in the earliest Campanian by cooler-water assemblages characterized by the Prunobrachidae. The changes in the assemblages of planktonic foraminifera and radiolarians at the Santonian–Campanian boundary are attributed to changes in palaeoceanography and the influence of more Boreal-like conditions.Three significant episodes of sea level change can be identified in the Cenomanian–Campanian of the Crimea–Caucasus area. The first is associated with the Albian–Cenomanian boundary, the second at the base of OAE2, and the third in the Mid–Early Late Turonian. This latter event had different durations in the Crimea and Caucasus regions and this could be related to more local tectonic processes.

Upper Campanian calciclastic turbidite sequences from the Hacımehmet area (eastern Pontides, NE Turkey): integrated biostratigraphy and microfacies analysis

Abstract The upper Campanian (Cretaceous) of the Hacımehmet area (south of the city of Trabzon; Eastern Pontides) is mainly composed of calciclastic turbidites. The basinal unit of the 119 m thick succession includes thin red pelagic limestone interlayers and conglomerates dominated by volcanic clasts. The overlying upper slope and lower slope units of the sequence consist of an alternation of allochthonous calcarenite/calcirudite beds and pelagic marls and mudstones. Calcarenite/calcirudite beds dominate the upper slope unit of the succession and are composed of transported material, including benthic foraminifers, red algae, bryozoan, crinoid and rudist fragments, inoceramid bivalve prisms and neritic and pelagic carbonate lithoclasts. The occurrence of Helicorbitoides boluensis (Sirel) extracted from the calcarenite/calcirudite beds indicates a Campanian age. Identifiable rudists such as Joufia reticulata Boehm, Bournonia cf. anatolica Ozer, Biradiolites cf. bulgaricus Pamouktchiev and ?Biradiolites sp. from the upper slope unit of the succession indicate a late Campanian- Maastrichtian age. The planktonic foraminifers within the red pelagic limestone beds, marls and mudstones throughout the succession consist mainly of Campanian-Maastrichtian forms and suggest mainly basinal depositional conditions. The presence of Radotruncana cf. calcarata (Cushman) accompanied by Globotruncanita elevata (Brotzen) in the basinal unit of the succession indicates an early late Campanian age for the lower part of the succession. Inoceramid bivalves have been collected from the upper part of the succession. The fauna is dominated by ‘Inoceramus’ tenuilineatus Hall and Meek, 1854 and Cataceramus haldemensis (Giers, 1964); other taxa recognised are: ‘Inoceramus’ algeriensis Heinz, 1932, Platyceramus vanuxemi (Meek and Hayden, 1860), ‘Inoceramus’ cf. nebrascensis Owen, 1852, Cataceramus aff. barabini (Morton, 1834), Cataceramus gandjaensis (Aliev, 1956), and ‘Inoceramus’ sp.; the assemblage indicates the ‘Inoceramus’ tenuilineatus Zone; corresponding to the middle-late Campanian boundary interval. The uppermost part of the succession is characterized by the presence of the trace fossils Scolicia strozzii and Scolicia isp., indicating a mixed Skolithos-Cruziana ichnofacies. This ichnofacies suggests a well-oxygenated environment.

Late Cretaceous climatic trends and a positive carbon isotope excursion at the Santonian–Campanian boundary in British Columbia, northeastern Pacific

This study presents oxygen and carbon isotope data obtained from well-preserved ammonite and bivalve fossils of the Upper Cretaceous Nanaimo Group of southwestern British Columbia, Canada. Palaeotemperatures for the late Santonian–Campanian of British Columbia, determined on the basis of oxygen isotopic analysis, suggest a õdirect relationship with basic Late Cretaceous climatic trends (e.g. temperature fall toward the cool climates of the Maastrichtian). The coolest Campanian palaeotemperatures were calculated from the ammonite Pachydiscus cf. ootacodensis (Stoliczka) (11.3–26.4°C) and the bivalve Inoceramus vancouverensis Shumard (about 19.7°C), from the late Campanian Occidentalis Zone (Northumberland Formation). In contrast, the highest palaeotemperatures were obtained from the shells of presumed earliest Campanian bivalves and varied between 25.1 and 33.7°C, which we assume to represent the regional expression of the early Campanian warming event.The Santonian–Campanian boundary in British Columbia is associated with a positive δ13C excursion (to 4.2‰) which appears to be contemporaneous with the Santonian–Campanian Boundary Event reported recently from other regions (i.e., Europe, Tunisia, Japan, and Tibet). The lack of organic-rich laminated black shales (indicating strong oxygen depletion in the marine realm) through the Santonian–Campanian of the Nanaimo Group, including the Santonian–Campanian boundary interval, seems to be in agreement with the suggestion that most of the world's oceans were characterised by oxygen-rich deep waters during Coniacian–Campanian time.

Volgian and Santonian—Campanian Radiolarian Events of the Russian Arctic and Pacific Rim

Radiolarians are widely distributed in two siliceous intervals that coincide with the Tithonian—Berriasian and Santonian— Campanian boundaries in the Mesozoic of the Russian Arctic and Pacific Rim. The first level is rich in organic matter and typical of Jurassic—Cretaceous boundary strata from the Russian North European Margin (Barents-Pechora, Volga-Urals, and Siberian hydrocarbon provinces, as well as western Kamchatka). Abundant and diverse representatives of the family Parvicingulidae provide a basis for establishing the new genus Spinicingula (uppermost Middle Volgian—Lower Berriasian); another new genus, Quasicrolanium (Upper Volgian—Upper Berriasian) is also described. A Santonian— Campanian siliceous interval with radiolarians is documented from the margins of northern Asia (eastern Polar Ural, Kara Basin, Kamchatka). The Boreal genus Prunobrachium makes its first appearance at the Santonian—Campanian boundary and reaches an acme in Campanian strata. Radiolarian data can be used for basin biostra...

Cyclostratigraphy of the reference section for the Cretaceous white chalk of northern Germany, Lägerdorf–Kronsmoor: A late Campanian–early Maastrichtian orbital time scale

New carbonate records of the upper Campanian–lower Maastrichtian white chalk of northern Germany at Lägerdorf–Kronsmoor represent a continuous succession suitable for time series analysis. The boreal chalk succession is characterized by several intervals of reduced carbonate content in the basiplana/spiniger, polyplocum, upper langei and upper grimmensis/granulosus to pseudoobtusa boreal macrofossil zones, which are mainly related to periods of increased detrital supply. Results of spectral analysis on the carbonate time series allow the detection of the periodicities of long and short eccentricity. The long eccentricity signal can be extended to the entire Upper Campanian comprising a total of 15.25 long eccentricity cycles, a minimum time span of 6.2 Ma and an age of 77.5 ± 0.4 Ma for the lower–upper Campanian boundary. The long eccentricity cycles detected from chalk carbonate contents correlate with long eccentricity cycles detected in self-potential logs of boreholes proving their significance within different depositional settings and rates of subsidence in the North German Basin. The biostratigraphic consistent occurrence of long eccentricity cycles provides evidence for the completeness of the sedimentary record. The long-term intervals of increased detrital supply are the expression of increased progradation of clay minerals related to a long-term sea-level fall with superimposed short sea-level falls within a 2.5 million year interval spanning the Campanian–Maastrichtian boundary. It cannot be decided from the present state of knowledge if this signal is controlled by increased erosion due to uplift of inverted structures, by eustatic sea-level fall or a combination of both. The detection of the long eccentricity suggests an orbital forcing superimposed on a long-term regressive trend.

Late Santonian bioevents in the Schattau section, Gosau Group of Austria – implications for the Santonian–Campanian boundary stratigraphy

The Schattau section in the Gosau Group (Northern Calcareous Alps) records a late Santonian interval in the northwestern Tethys. The crinoid Marsupites laevigatus, which indicates the lower part of the latest Santonian Marsupites zone, has been found within a Micraster bed in the Bibereck Formation. Co-occurring ammonites, such as Boehmoceras arculus and Placenticeras maherndli, indicate a late Santonian age. The upper Santonian zonal markers Placenticeras paraplanum and Cordiceramus muelleri muelleri, which occur below the Micraster bed, in the Sandkalkbank Member (Hochmoos Formation), indicate the upper Santonian paraplanum Zone. Within the Micraster bed, the planktonic foraminifera Globotruncanita cf. elevata and Globotruncanita stuartiformis have their first (local) appearance. Dicarinella asymetrica is still present up to the top of the section, indicating the asymetrica–elevata Concurrent Range Zone. Nannofossils give evidence for the CC17 and UC12-13 standard zones. Strontium and carbon isotope data, albeit interpreted with caution, allow some further correlations of the section. This indicates that Globotruncanita elevata and Globotruncanita stuartiformis have their first occurrences in the late Santonian. The first occurrence of the nannofossil Broinsonia parca parca, which defines the base of the CC18/UC14 standard zones, was found in neighbouring sections and is an early Campanian event.