Planktonic Foraminiferal Biostratigraphy Research Articles

Paleocene stratigraphy in Egypt

The Egyptian Paleocene is widely distributed with vertical and lateral facies changes geographically separated and subject to different tectonic and sedimentary regimes. Five coeval facies associations of the Paleocene outcrops are identified and named from south to north: Garra El-Arbain, Nile Valley, Farafra, Sinai, and Southern Galala. Ten Paleocene third-order depositional sequences (Ds Da1 to Ds Th9) are tentatively distinguished in Egypt. These are bounded at their base and top by ten sequence boundaries (Eg.Da-1, Eg.Da-2, Eg.Da-3, Eg.Da-4, Eg.Da-5, Eg.Da-6, Eg.Se-7, Eg.Th.-8, Eg.Th.-9, and Eg.Eo-10). The relative ages and correlation of the Paleocene depositional sequences are based on planktonic foraminiferal biostratigraphy. Comparison of identified Paleocene sequences in and outside Egypt are referred to eustatic sea-level changes and partly to regional tectonics events, which have caused hiatuses of variable durations and different configurations of Paleocene sedimentary regimes from place to place.

Miocene–Pliocene planktonic foraminiferal biostratigraphy of the Pearl River Mouth Basin, northern South China Sea

AbstractThe present study deals with the planktonic foraminiferal biostratigraphy of the Miocene–Pliocene sequence of three petroleum exploration wells (BY7-1-1, KP6-1-1 and KP9-1-1) in the Pearl River Mouth Basin (PRMB). In general, the three wells contain a fairly well-preserved, abundant foraminiferal fauna. The proposed planktonic foraminiferal zonation follows the scheme updated by Wade et al. (2011). Nineteen planktonic foraminiferal zones have been recognized, 14 zones (zones M1–M14) for the Miocene and 5 zones (zones PL1–PL5) for the Pliocene. The zonation is correlated with previously published biostratigraphic subdivisions of the Neogene succession in the PRMB and with international foraminiferal zonations. The zonal boundaries are mostly defined by the last appearance datum of zonal taxa of planktonic foraminifera, which is more reliable than the FAD (first appearance datum) events for ditch cutting sampling. Changes in the coiling of Globorotalia menardii (s. l.) are also used to define the zonal boundaries, where no LADs (last appearance datum) are available. The Fohsella fohsi group, comprising useful taxa for delimiting zonal boundaries of the middle Miocene in other areas, has a poor record within the Pearl River Mouth Basin due to unfavorable ecological conditions, and cannot be used for the studied wells. Different from the previously reported zonal scheme for the PRMB, the present zonation is based on correlation with the current standard planktonic foraminiferal zonation, with calibrated absolute ages.

The Lutetian/Bartonian transition (middle Eocene) at the Oyambre section (northern Spain): Implications for standard chronostratigraphy

With the aim of finding a potential Global Stratotype Section and Point (GSSP) for the base of the Bartonian Stage, an integrated stratigraphic study was carried out in the Acebosa Fm exposed at the Cape of Oyambre (Cantabria, Spain). While the Oyambre section does comply with the majority of the requirements of the International Commission on Stratigraphy, several shortcomings were also found, which apparently make it unsuitable for the GSSP for the base of the Bartonian Stage. An unexpected finding was that the chronostratigraphic calibration of the Oyambre planktonic foraminiferal events revealed major discrepancies with the standard timescale. The lowest occurrence of Globigerinatheka index was found in the upper part of Chron C20r, and not in the upper part of C20n as depicted in the standard chart, being dated at 43.68Ma and not at 42.64Ma. The lowest occurrences of Turborotalia pomeroli and Globigerinatheka euganea were found in the upper part of calcareous nannofossil Zone CP14a (40.92Ma), and not in the upper part of Zone CP13c (42.21Ma). Finally, the highest occurrences of Guembelitrioides nuttalli and Morozovelloides bandyi were also found in the upper part of Zone CP14a (40.68Ma), and not in the upper part of Zone CP13c (42.07Ma). The accuracy of these anomalous results was further substantiated with data from other areas, strongly suggesting that the standard Eocene chronostratigraphy was in need of amendment. The Oyambre findings, if proven significant at a global scale, would have two important chronostratigraphic outcomes. Firstly, the standard Eocene planktonic foraminiferal biostratigraphy would need revision, as there would be practically no space to accommodate zones E9 and E11. Secondly, an array of sound biostratigraphic markers would now be defined around Chron C19n, which has been considered the best marker for the Lutetian/Bartonian boundary, thus facilitating correlation of a potential GSSP.

Planktonic foraminiferal biostratigraphy of the Campanian–Ypresian in the İzmit Province, Kocaeli Peninsula, Turkey

The study of the Campanian–Ypresian planktonic foraminiferal biostratigraphy in two surface sections including three different formations in the Izmit region. These formations begin at its Akveren Formation, consisting of Late Campanian–Selandian deep shelf and deep marine deposits. The deep shelf turbidites of the Atbasi Formation were deposited during the Selandian–Ypresian, whereas the Ypresian is characterized by shallow shelf-type deposits of the Caycuma Formation. A total of 14 planktonic foraminifera biozones have been identified. The defined planktonic foraminiferal biozones from older to younger are Pseudoguembelina palpebra Partial-range Zone, Racemiguembelina fructicosa Partial-range Zone, Abathomphalus mayaroensis Partial-range Zone, Pseudoguembelina hariaensis Partial-range Zone, Parvularugoglobigerina eugubina Taxon-range Zone (Pα), Parasubbotina pseudobulloides Partial-range Subzone (P1a), Subbotina triloculinoides Lowest Occurrence Subzone (P1b), Globanomalina compressa/Praemurica uncinata Lowest Occurrence Subzone (P1c), Praemurica uncinata Lowest Occurrence Zone (P2), Morozovella angulata Lowest Occurrence Zone (P3), Globanomalina pseudomenardii Taxon-range Zone (P4), Morozovella velascoensis Partial-range Zone (P5), Pseudohastigerina wilcoxensis/Morozovella velascoensis Concurrent-range Zone (E2), Morozovella marginodentata Partial-range Zone (E3).

Planktonic Foraminiferal Biostratigraphy, Microfacies Analysis, Sequence Stratigraphy, and Sea-Level Changes Across the Cretaceous-Paleogene Boundary In the Haymana Basin, Central Anatolia, Turkey

Abstract The Cretaceous–Paleogene (K/Pg) boundary in the Haymana Basin, Central Anatolia, Turkey, was delineated using planktonic foraminiferal biostratigraphy, microfacies analysis, and sequence stratigraphy. An ∼ 29 m outcrop consisting of limestone and marl was measured, and four planktonic foraminiferal biozones were identified spanning the boundary. Planktonic foraminiferal extinction across the K/Pg boundary was catastrophic and abrupt. The extinction level is overlain by a unit (Zone P0) showing an increase in echinoid fecal pellets and authigenic clay minerals such as glauconite, suggesting low sedimentation rates in the early Danian. Ten microfacies types were identified indicating inner-ramp to basinal paleoenvironments based on the sedimentological characteristics and microfossil and macrofossil assemblages. Maastrichtian carbonates contain large benthic foraminifera, calcareous red algae, bryozoans, fragments of echinoderms and mollusks, and planktonic foraminifera. Overlying Maastrichtian–Danian silty marls and silty limestones have common planktonic and benthic foraminifera. Progradation of carbonates into the basin took place during the highstand systems tract, and deposition of a silty marl succession occurred during the transgressive systems tract. The K/Pg boundary is in the upper part of the transgressive systems tract, below a maximum flooding surface. Sequence stratigraphic analysis of a second section, Campo Pit, New Jersey, USA, showed that the K/Pg boundary occurs within a transgressive systems tract in New Jersey as well, suggesting a global sea-level rise across the K/Pg boundary.

Planktonic foraminiferal biostratigraphy and assemblages in the Bering Sea during the Pliocene and Pleistocene: IODP sites U1340 and U1343

IODP Site U1340 and Site U1343 in the Bering Sea have been investigated with regard to planktonic foraminifers and fragmentation. The base of Site U1340 dates back to the Early Pliocene and the base of Site U1343 to the Early Pleistocene. Site U1340 is situated at Bowers Ridge, the southern Bering Sea. Site U1343 is situated near the gateway to the Arctic Ocean in the northern Bering Sea. At both sites there are none or very few planktonic foraminifers during the Pliocene and early Pleistocene. After 1.3–1.4Ma the planktonic foraminifers are continuously present for most of the samples examined. Three stratigraphic events have been identified in this study. The first occurrence (FO) of Neogloboquadrina inglei is observed at 1.4–1.5Ma, although this event may be affected by poor preservation of foraminifers in older sediments. The observed age of the change in the coiling ratio of Neogloboquadrina pachyderma from right to left at 1.2Ma agrees with the dating of the same event at the Californian margin. The age of the last occurrence (LO) of N. inglei also seems to match the same event from the Californian margin at 0.7Ma. This implies that these events are robust regional events for the entire northern Pacific. Multivariate analyses of the quantitative planktonic foraminifer data show three main faunal assemblages. The oldest assemblage from 1.3–1.4Ma to 1.2Ma is dominated by N pachyderma s.l. (dex) together with Globigerina bulloides. Other species in this fauna are N. inglei, N. pachyderma s.l. (sin), Globigerina umbilicata and Turborotalita quinqueloba. After 1.2Ma the faunal assemblage is dominated by N. pachyderma s.l. (sin), but the remaining species are the same as before. At 0.7Ma N. inglei disappears, whilst the remaining fauna assemblage stays the same, with N. pachyderma s.l. (sin) still dominating, reflecting subpolar–polar conditions. Prior to 1.4–1.3Ma there are very few or no planktonic foraminifers. Low shell fragmentation and lower TOC suggest that the lack of planktonic foraminifers in these sediments cannot be explained either by a shoaling of the carbonate compensation depth or by enhanced supralysoclinal dissolution. Instead, we argue that the appearance of abundant foraminifers in the sediment reflects the same evolutionary adaption of N. pachyderma (sin) to cold conditions to have occurred after 1.1–1.0Ma as in the North Atlantic.

Mass wasting and hiatuses during the Cretaceous-Tertiary transition in the North Atlantic: Relationship to the Chicxulub impact?

Deep-sea sections in the North Atlantic are claimed to contain the most complete sedimentary records and ultimate proof that the Chicxulub impact is Cretaceous-Tertiary boundary (KTB) in age and caused the mass extinction. A multi-disciplinary study of North Atlantic DSDP Sites 384, 386 and 398, based on high-resolution planktonic foraminiferal biostratigraphy, carbon and oxygen stable isotopes, clay and whole-rock mineralogy and granulometry reveals the age, stratigraphic completeness and nature of sedimentary disturbances. Results show a major hiatus across the KTB at Site 384 with Zones CF1, P0 and P1a missing, spanning at least ~540ky, similar to other North Atlantic and Caribbean localities associated with tectonic activity and Gulf Stream erosion. At Sites 386 and 398, discrete intervals of disturbed sediments with mm-to-cm-thick spherule layers have previously been interpreted as the result of impact-generated earthquakes at the KTB destabilizing continental margins prior to settling of impact spherules. However, improved age control based on planktonic foraminifera indicates spherule deposition in the early Danian Zone P1a(2) (upper Parvularugoglobigerina eugubina Zone) more than 100ky after the KTB. At Site 386, two intervals of white chalk contain very small (<63μm) early Danian Zone P1a(2) assemblages (65%) and common reworked Cretaceous (35%) species. In contrast, the in situ red-brown and green abyssal clays of this core are devoid of carbonate. In addition, high calcite, mica and kaolinite and upward-fining are observed in the chalks, indicating downslope transport from shallow waters and sediment winnowing via distal turbidites. At Site 398, convoluted red to tan sediments with early Danian and reworked Cretaceous species represent slumping of shallow water sediments as suggested by dominance of mica and low smectite compared to in situ deposition. We conclude that mass wasting was likely the result of earthquakes associated with increased tectonic activity in the Caribbean and the Iberian Peninsula during the early Danian well after the Chicxulub impact.

Revised Upper Albian – Maastrichtian planktonic foraminiferal biostratigraphy and magneto-stratigraphy of the classical Tethyan Gubbio section (Italy)

Revised Upper Albian – Maastrichtian planktonic foraminiferal biostratigraphy and magneto-stratigraphy of the classical Tethyan Gubbio section (Italy)

Integrated biostratigraphy of the upper Oligocene–middle Miocene successions in west central Sinai, Egypt

The nannofossil and planktonic foraminiferal biostratigraphy in four upper Oligocene–middle Miocene sections are examined in Nukhul–Sudr area of west central Sinai, Egypt. The integration of calcareous nannofossils and planktonic foraminifera is used to verify the ages and determine the biozones of the upper Oligocene–middle Miocene units in the studied area. This target is important in the light of the great lithofacies changes during the time interval. The detailed examination of the nannofossil and planktonic foraminiferal contents in these sections led to identification of 86 calcareous nannofossil species belonging to 22 genera, 10 families and 3 orders, in addition to 64 planktonic foraminiferal species belonging to 11 genera, 4 families and 2 superfamilies. The identified nannofossil and planktonic foraminiferal assemblages allow to distinguish five calcareous nannofossil biozones and six planktonic foraminiferal biozones. The biostratigraphic integration suggested the Chattian–Aquitanian age for the Nukhul Formation where the Globigerina ciperoensis Zone (P22) and Globigerinoides primordius Zone (M1a) correspond to calcareous nannofossil Sphenolithus ciperoensis Zone (NP25) and Discoaster druggii Zone (NN2), respectively. The Rudeis Formation is assigned to the Burdigalian–Langhian age depending on correspondence of Catpsydrax dissimilis Zone (M2), Globigerinoides bisphericus Zone (M4b) and Praeorbulina sicana Zone (M5) with Discoaster druggii zone (NN2), Sphenolithus belemnos Zone (NN3) and Helicosphaera ampliaperta Zone (NN4). The Somar Formation is found barren ofany microfossils, but it contains index pectens and oysters of Burdigalian age which may be equivalent to the lower part of the Rudeis Formation. The Kareem and Sarbut El-Gamal formations are represented by evaporitic and conglomeratic succession, where no foraminifera or nannofossils are recorded and assigned to the Langhian age according to their stratigraphic position. The Belayim Formation is assigned to the Serravallian age, due to the presence of Globorotalia fohsi Zone (M8) which equivalent to Discoaster exilis Zone (NN6).

Planktonic foraminiferal biostratigraphy and paleoecology of Upper Cretaceous deposits from the Palmyride Region, Syria

Planktonic foraminifera were quantitatively analyzed across the Upper Coniacian - Lower Campanian succession at Jebel Ennahli and Ettout sections, northern Tunisia. This succession is characterized by hemipelagic facies domainated by a continuous sedimentary succession, allowing a good biostratigraphic correlation for this time interval. 55 planktonic foraminiferal species have been identified belonging to 13 genera. The distribution pattern of 17 heterohelicids and 38 trochospiral forms reveals to the identification of12 major bio-events and establishing three zones based on heterohelicids and five zones based on trochospiral forms. The trochospiral based zones are from base to top: Dicarinella primitiva Interval Zone, Dicarinella concavata Interval Zone, Dicarinella asymetrica Total Range Zone, and Globotruncanita elevata/Globotruncana arca Concurrent Range Zone, Globotruncana ventricosa Interval Zone; while the three heterohelicid based planktonic foraminiferal biozones are: Pseudotextularia nuttalli Interval Zone, Sigalia carpatica Interval Zone, Ventilabrella eggeri/Planoglobulina manuelensis Concurrent Range Zone. The bioevents and planktonic foraminiferal zones were correlated with the previously published works especially in Tunisia and other palaeolatitude provinces. There are no significant planktonic foraminiferal datums recorded across the Coniacian/Santonian boundary (CSB) except the lowest occurrence (LO) of Dicarinella asymetrica , which was recorded slightly below the LO of inoceramid Platyceramus cycloides cycloides representing a good proxy for the CSB. The Santonian/Campanian boundary of the studied sections are characterized by a major turnover represented by the highest occurrence of Sigalia , Dicarinella and Whiteinella genera; in addition to the lowest occurrence of Ventilabrella and Planoglobulina genera and above slightly the LO Globotruncana and Globotruncanita .

Upper Paleocene–lower Eocene planktonic foraminiferal biostratigraphy of Gabal Matulla section, southwestern Sinai, Egypt

In Egypt, the Paleocene/Eocene successions are distributed on a wide area. Fifty-nine samples span Tarawan, Esna, and the lower part of Thebes Formations were collected from Matulla section, southwestern Sinai, Egypt, to study the planktonic foraminiferal events across the P/E boundary. Four planktonic foraminiferal biozones were recognized, and 49 species were identified at this interval. The base of Eocene boundary (base of Ypresian) was defined at sample M79 based on the first appearance of Pseudohastigerina wilcoxensis and Acarinina sibaiyaensis which coincides with the last appearance of Angulogavelinella avnimelechi and Neoflabellina jarvisi (benthonic foraminifera) at sample M78. The fluctuations in the relative abundance and absolute abundance of planktonic, benthonic, morozovellids, acarininids, and subbotinids were also studied across the Paleocene/Eocene boundary at Matulla section.

Planktonic Foraminiferal Biostratigraphy and Paleoecology of the Miocene Sequence in the Area Between Wadi Gharandal and Bir Haleifiya, Gulf of Suez Region, Egypt

Planktonic Foraminiferal Biostratigraphy and Paleoecology of the Miocene Sequence in the Area Between Wadi Gharandal and Bir Haleifiya, Gulf of Suez Region, Egypt

A refined foraminiferal biostratigraphy for the Late Campanian–Early Maastrichtian succession of northeast Iraq

ABSTRACTSpecies of the benthonic foraminiferal genus Bolivinoides provide a refined biostratigraphic biozonation for the Late Campanian to Early Maastrichtian (Late Cretaceous) Shiranish Formation in NE Iraq. Three biozones and two subzones are identified: the Bolivinoides decoratus Biozone (Late Campanian) subdivided into a lower B. decoratus Subzone and upper B. laevigatus Subzone; the B. miliaris Biozone (Earliest Maastrichtian); and the B. draco Biozone (late Early Maastrichtian). These zones can be related to the biostratigraphical interval of the Globotruncana aegyptiaca (Late Campanian), Gansserina gansseri (latest Campanian–Early Maastrichtian) and Contusotruncana contusa (late Early Maastrichtian) planktonic foraminiferal biozones. Combined, the benthonic and planktonic foraminiferal biostratigraphy enables the informal recognition of lower and upper intervals within both the Globotruncana aegyptiaca and Gansserina gansseri biozones that may be important for more refined inter-regional correlation in the Middle East and North Africa. The new Bolivinoides biozonation precisely locates the Campanian–Maastrichtian boundary in NE Iraq. The foraminiferal assemblages also constrain the timing of a shallowing marine trend in the Shiranish Formation beginning from the latest Campanian that is consistent with shallowing facies noted globally at this time.

Late Cretaceous paleoenvironmental evolution of the Tarfaya Atlantic coastal Basin, SW Morocco

Lithological evidence, benthic foraminiferal census counts, and X-ray fluorescence (XRF) scanner-derived elemental data were integrated with planktonic foraminiferal biostratigraphy and bulk carbonate stable isotopes to retrace the Turonian to early Campanian paleoenvironmental evolution and sea-level history of the Tarfaya Atlantic coastal basin (SW Morocco). The lower Turonian is characterized by laminated organic-rich deposits, which contain impoverished benthic foraminiferal assemblages, reflecting impingement of the oxygen minimum zone on the shelf during a sea-level highstand. This highstand level is correlated to the global transgressive pulse above the sequence boundary Tu1. The appearance of low-oxygen tolerant benthic foraminiferal assemblages dominated by Gavelinella sp. in the middle to upper Turonian indicates an improvement in bottom water oxygenation, probably linked to offshore retraction of the oxygen minimum zone during a regressive phase. This interval is marked by major regressive events expressed by a series of erosional truncations associated with the prominent sequence boundaries Tu3 and/or Tu4. Dysoxic–anoxic conditions recorded in the upper Santonian of the Tarfaya Basin coincide with the eustatic sea-level rise prior to Sa3 sequence boundary. The lower Campanian transgression, only recorded in the southern part of the Tarfaya Basin, coincided with substantial deepening, enhanced accumulation of fine-grained clay-rich hemipelagic sediments and improved oxygenation at the seafloor (highest diversity and abundance of benthic foraminiferal assemblages). Stable isotope data from bulk carbonates are tentatively correlated to the English Chalk carbon isotope reference curve, in particular the Hitch Wood Event in the upper Turonian, the Navigation Event in the lower Coniacian, the Horseshoe Bay Event in the Santonian and the Santonian/Campanian Boundary Event.

Planktonic Foraminiferal Biostratigraphy and Correlation Across the Cretaceous-Paleogene Transition at the Tethyan and the Atlantic Realms

Based on high-resolution planktonic foraminiferal biostratigraphical analysis at El Kef stratotype section (GSSP for the K/Pg boundary), Ellès section in Tunisia, and Agost and Caravaca sections in Spain (Tethyan realm), we attempt to compare biozones and subzones with those of the Bidart section (SW France) (Atlantic realm). TheAbathomphalus mayaroensiszone of the upper Maastrichtian corresponds to the taxon range interval of the nominate species. We have identified thePlummerita hantkeninoidessubzone. This species is present and associated withPseudoguembelina hariaensisat the Tethyan realm. However, this species is absent at the middle latitude of the Atlantic realm (Bidart section, SW France). ThePseudoguembelina hariaensisspecies had larger paleogeographic spread, as it was present in both the Tethys and the Atlantic paleoceans. It is more relevant to be considered as the biomarker of a nominate uppermost Maastrichtian subzone instead ofPlummerita hantkeninoides. The Danian stage is characterized by theGt. cretaceazone,Pv. eugubinazone, and theParasubbotina pseudobulloideszone. The deposition thickness of the zones and subzones at El Kef stratotype section and Ellès section is more expanded than at Agost and Caravaca sections (Spain) and Bidart section (France). They would be controlled by the sedimentary basin morphology.

High resolution planktonic foraminiferal biostratigraphy of the Gurpi Formation, K/Pg boundary of the Izeh Zone, SW Iran

High resolution planktonic foraminiferal biostratigraphy of the Gurpi Formation, K/Pg boundary of the Izeh Zone, SW Iran

Middle Miocene to Pleistocene Planktonic Foraminiferal Biostratigraphy in the Eastern Equatorial Pacific Ocean

Abstract. We present a detailed dataset of planktonic foraminiferal biohorizons to enhance a biostratigraphy for the eastern equatorial Pacific. Middle Miocene to Pleistocene planktonic foraminiferal biostratigraphy is established using 269 samples from Cores 1H to 40H recovered from Integrated Ocean Drilling Program (IODP) Hole U1338B. In addition to the onboard study of Hole U1338A, a total of 60 biohorizons are recognized with three grades of reliability. Generally, these biohorizons are in agreement with each other and consistent with shipboard magnetostratigraphy, except for several discrepancies that may be caused by ecological diachronous processes. The studied sequence can be correlated with Zone M7 to Subzone PT1b. However, we cannot detect Miocene zones M6, M10, and M12 in this sequence because of discrepancies in some zonal marker biohorizons.

Middle Miocene to Pleistocene planktonic foraminiferal biostratigraphy of IODP Site U1338 in the eastern equatorial Pacific.

Middle Miocene to Pleistocene planktonic foraminiferal biostratigraphy of IODP Site U1338 in the eastern equatorial Pacific.

Planktonic foraminiferal biostratigraphy of the Plio-Pleistcene Chikura Group, southernmost part of the Boso Peninsula, central Japan and inferred sea surface environmental changes

Planktonic foraminiferal biostratigraphy of the Plio-Pleistcene Chikura Group, southernmost part of the Boso Peninsula, central Japan and inferred sea surface environmental changes

Planktonic foraminifer biostratigraphy as a tool in constraining the timing of flysch deposition: Gurnigel flysch, Voirons massif (Haute‐Savoie, France)

AbstractNew biostratigraphic, sedimentological and petrographic data and a thorough review of existing literature modify existing knowledge on the age, the sedimentology, the petrography and the palaeogeographic origin of the Gurnigel flysch from the Voirons massif (Haute Savoie, France). Planktonic foraminiferal biostratigraphy assigns the flysch to the upper Middle Eocene (zones P12 to P14) through to Lower Oligocene (zones P16 to P20) stages. This result contrasts with previous work, which assigned the unit to the Lower Palaeocene to upper Middle Eocene on the basis of calcareous nannofossil and dinoflagellate assemblages. The following findings suggest that the Voirons massif comprises several stacked flysch units that do not have exactly the same palaeogeographic origin: (i) the occurrence of flysch exposures in reverse stratigraphic order combined with the lack of evidence for bed overturning; (ii) the variability of palaeo‐depositional settings inferred from different flysch outcrops of similar age; (iii) the differences in the heavy mineral content; and (iv) the anomalous superimposition of distal turbidites and/or basinal contourites (Saxel Marls) over proximal turbidites (Vouan Conglomerates). The young age of these kilometre‐sized flysch slices precludes their hitherto postulated locus of deposition in the South‐Penninic Ocean, and rather indicates a provenance from the Ultrahelvetic and/or North‐Penninic (Valais) palaeogeographical domains. Finally, none of the nannofossil assemblages are contemporaneous with the observed planktonic foraminifera associations, suggesting that they have been reworked, dissolved, or just simply diluted and not found by earlier researchers. This study from the Voirons massif shows that planktonic foraminifera associations are a highly reliable biostratigraphic tool for obtaining accurate ages of flysch successions.