Paleocene Age Research Articles

Potential hydrocarbon reservoirs of Albian–Paleocene age in the Nuussuaq Basin, West Greenland

The onshore Nuussuaq Basin in West Greenland is important for hydrocarbon exploration since many of the key petroleum systems components are well exposed and accessible for study. The basin has thus long served as an analogue for offshore exploration. The discovery of oil seeps on Disko, Nuussuaq, Ubekendt Ejland, and Svartenhuk Halvø (Fig. 1) in the early 1990s resulted in exploration onshore as well. In several wells, oil stains were observed in both the siliciclastic sandstone and in the volcanic series. An important aspect of any petroleum system is a high quality reservoir rock. The aim of this paper is to review petrophysical aspects of the reservoir potential of key stratigraphic intervals within the Nuussuaq and West Greenland Basalt groups. Reservoir parameters and porosity–permeability trends for potential siliciclastic and volcanic reservoirs within the relevant formations of the Nuussuaq Basin are discussed below.

Paleocene echinoid faunas of the eastern United States

AbstractTwenty-one species of echinoid are reported from Paleocene rocks of the eastern United States along the outcrop belt from Texas to New Jersey. Six of these are strictly early Paleocene age (Danian), nine strictly late Paleocene age (Thanetian), five range throughout the Paleocene, and one previously reported Paleocene species (Diplodetus moscovensis) is most likely a Cretaceous species. Two new species are described,Salenia palmyran. sp., from the Danian Clayton Formation in Alabama and Georgia, andOva rancocan. sp., from the Thanetian Vincentown Formation in New Jersey. One new species from the Clayton Formation in Mississippi,Arbaciella? sp., is left in open nomenclature.

The age of the Takatika Grit, Chatham Islands, New Zealand

Hollis, C.J, Stickley, C.E., Bijl, P.K., Schiøler, P., Clowes, C.D., Li, X, Campbell, H. March 2017. The age of the Takatika Grit, Chatham Islands, New Zealand. Alcheringa 41, xxx–xxx. ISSN 0311-5518.The oldest Paleogene strata on Chatham Islands, east of New Zealand, are the phosphatized conglomerates and sandstones of the Takatika Grit that crops out on the northeastern coast at Tioriori and unconformably overlies the Chatham Schist. An intact Cretaceous–Paleogene boundary transition is not preserved at this locality. New biostratigraphic analysis of dinoflagellate, diatom and radiolarian microfossil assemblages confirms that the Takatika Grit is of late early–middle Paleocene (New Zealand Teurian stage) age but contains reworked microfossils of early Campanian (Early Haumurian) age. Vertebrate fossils found in this unit are inferred to be a mixture of reworked Cretaceous and in situ Paleocene bones and teeth. The overlying Tutuiri Greensand is of middle–late Paleocene age in its lower part and also contains reworked Cretaceous microfossils.Christopher J. Hollis [c.hollis@gns.cri.nz], Chris Clowes [c.clowes@gns.cri.nz], Xun Li [x.li@gns.cri.nz], Hamish Campbell [h.campbell@gns.cri.nz], GNS Science, PO Box 30-368, Lower Hutt 5040, New Zealand; Catherine Stickley, Evolution Applied Limited, 50 Mitchell Way, Upper Rissington, Cheltenham GL54 2PL, UK [catherine.stickley@gmail.com]; Peter Bijl [p.k.bijl@uu.nl], Marine Palynology and Paleoceanography, Department of Earth Sciences, Utrecht University, 3584 CS Utrecht, the Netherlands; Poul Schiøler [poul.schioler@mgpalaeo.com.au], Morgan Goodall Palaeo, Unit 1/5 Arvida St, Malaga, WA 6090, Australia.

Sedimentological, Mineralogical and Geochemical Analysis of the Hyperthermal Latest Danian Event across the Galuconitic Marker Bed (Central Tunisia)

Field prospecting of the El-Haria Formation, which is Paleocene in age, leads to the discovery of the glauconitic marker bed in inner neritic to bathyal setting from Southern Tethyan realm. The recognition of this interval is based on lithological changes and an accurate stratigraphic proxy allows to distinguish of three main facies. The use of multivariate (cluster analysis and principal component analysis) and univariate (one-way Anova test) analysis confirm dissimilarities in composition between facies as testified by the significant differences. Sedimentological, geochemical and mineralogical analysis leads to assess paleo-environmental changes and to ascertain the variation of the lysocline and CCD across the glauconitic marker bed. Facies 1, particularly, rich in cobalt, sulfides and iron oxides reflects containment conditions affecting the surface and bottom water. These conditions lead to the extinction of the majority of benthic foraminifera and the disruption in planktonic foraminifers’ assemblage. In addition, the Facies 1 displays a brief shoaling of lysocline and CCD evidenced by the low calcite content, the bad preserved benthic foraminifera associated to the maximum fragmentation shells of planktonic foraminifera. In contrary, the rapid pattern of microfossil and the calcite recovery through the Facies 2 indicate suboxic to oxic conditions and a deepen lysocline and CCD. The cobalt lightly increases within the upper Facies, suggesting slightly oxygen deficient bottom water environment. The base of the glauconitic marker bed seems to be a lateral equivalent of the Latest Danian Event recorded throughout the Tethyan Realm (Spain and Egypt) and the Pacific Ocean.

The Ropianka Formation of the Bystrica Zone (Magura Nappe, Outer Carpathians): proposal for a new reference section in northwestern Orava

The thin- and medium-bedded, turbiditic deposits that are exposed in the Bystrica Zone of the Magura Nappe in the Slovak Orava region are the subject of this study. On the basis of lithological features as well as age and stratigraphic position, they are assigned to the Ropianka Formation. The very well exposed rocks of this formation, recognized in the Biela Farma profile in the Slovak part of the northwestern Orava region, are compared with analogous deposits in the Polish Orava and the Beskid Wysoki Mountains. Lithological and biostratigraphical documentation of the Ropianka Formation is presented. This documentation allowed the determination of the age of the rocks studied. Abundant and taxonomically diverse foraminiferal assemblages of agglutinated, benthonic and occasional planktonic forms indicate a Middle Paleocene age for the upper part of the Ropianka Fm. A new stratigraphic position for the Szczawina Sandstone, considered to be a member of the Ropianka Fm, is proposed. The lithostratigraphy of the Ropianka Fm in the Magura Nappe in Poland, Slovakia and the Czech Republic requires further investigation, including the establishment of new type and reference sections. The large outcrop at Biela Farma should be taken into consideration as a potential reference section. Studies of the new sections will lead to a new monographic elaboration of the Ropianka Fm in Poland, Slovakia and the Czech Republic.

Sequence stratigraphy of the Maastrichtian-Paleocene succession at the Dakhla Oasis, Western Desert, Egypt

The Maastrichtian-Paleocene succession at the Dakhla Oasis is marked by the presence of a typical Nile Valley Facies represented by the Dakhla and Tarawan formations in Edmonstone and Qur El Malik sections in the central and western parts of the oasis, while a mixed Nile Valley and Garra Al-Arbain facies represented by Dakhla, Kurkur and Tarawan formations in Teneida section in the eastern part of the oasis adjacent to the Abu Tartur Plateau. These sections were examined for their foraminiferal contents, lithologic characters and stratigraphic boundaries. The distribution of foraminifera in the studied sections is variable and inconstant, as the planktonics are concentrated only at certain levels, which may be considered as a time intervals of transgression and maximum flooding surfaces. Eight planktonic biozones are distinguished in this work; of theses two are of Maastrichtain age and six are of Paleocene age. Eight 3rd order depositional sequences are recognized in the studied Maastrichtian-Paleocene succession based on the time stratigraphic boundaries released from the planktonic foraminifera and sea level changes which are released from the paleoecologic interpretations. The distinguished sequences are subdivided into their systems tracts based on the paleobathymetric interpretations of P/B% and benthic biofacies analysis. These sequences are bounded by eight sequence boundaries (SB A - SB H) represented by unconformity surfaces and depositional hiatuses. The correlation of the sequence boundaries of the established depositional sequences with the eustatic sea level curve, suggesting that these depositional sequences were resulted from the interplay of eustatic sea-level changes and local tectonic activities.

Kraken 3D - acquisition to interpretation on the edge of the Browse

The broadband Kraken 3D Marine Seismic Survey was acquired during 2013 in the outer Browse Basin exploration permit WA-314-P with the specific goal of assessing risk and volumes at the Elvie prospect. The survey was acquired over a highly rugose sea floor, comprised of deep slump canyons that overlie a steeply prograding Miocene carbonate sequence. Multiple attempts at processing the seismic data have already been made; including a post-stack time migration (a fast-track volume), pre-stack time and pre-stack depth migration. Conventional processing and pre-stack depth migration approaches were unable to fully resolve short-wavelength velocity anomalies below the sea floor that cause obvious residual imaging problems and impact upon depth conversion and seismic amplitude interpretation. A geomechanical pre-stack depth migration now underway to hopefully address the remaining imaging concerns. Overall, the Kraken 3D is considered to be a significant improvement over the pre-existing 2D seismic. Interpretation was performed largely in the depth domain, although ties to nearby wells were made in the time domain using legacy 2D and 3D seismic. Mapping has further matured the Elvie prospect, which is a robust 4-way dip closure located on the divide between the Caswell and Seringapatam Sub-basins. The survey provides strong evidence for a thick top seal in the form of deep-marine muds of Miocene age, although there is evidence of minor seepage through a thin flank of the sealing unit. These shallow amplitude indicators, nearby surface seeps and pockmarks near the sea floor provide additional support for a working petroleum system. The Elvie structure appears to be draped by potentially high quality turbidite reservoirs of most-likely Paleocene age.

Correlation of the Palaeogene successions on the North-East Greenland and Barents Sea margins.

In this study we use seismic stratigraphy to link the Palaeogene succession of the North-East Green- land shelf with that of the more accurately dated Cenozoic succession on the partly conjugate Nor- wegian margin in the West Barents Sea. The margins show a comparable stacking of seismic facies and we propose that this symmetry reflects a genetic relationship between the conjugate plates. On both margins, the earliest deposition is constricted by highs inherited from Mesozoic rifting. On the North-East Greenland shelf, the Danmarkshavn Ridge forms a barrier, whereas the footwall uplift along the west margin of Veslemøy High constrains the deposition in the West Barents Sea area. Pronounced progradational events shifted the depocentres of both margins towards the central axis of breakup during the more tectonically active breakup phase. Deposition during the early drift stage is dominated by a relatively homogenous distribution of sediments across both margins and further basinward migration of the depocentres. Based on correlation of the seismic stratigraphic units, the Palaeogene succession of the North-East Greenland shelf is subdivided into pre-breakup deposits of early Paleocene age, syn-breakup deposits of latest Paleocene to early Eocene age and (early) drift deposits of late Eocene to Oligocene age.

Trilocular Palm Fruits from the Deccan Intertrappean Beds of India

Abundant silicified fruits formerly attributed to the Euphorbiaceae have been reinvestigated and found to represent Arecaceae. The fruits are from Ghughua near Shapura, in Madhya Pradesh, central India, of probable early Paleocene age. Fruits of Palmocarpon drypeteoides (Mehrotra, Prakash et Bande) comb. nov. are trilocular indehiscent drupes. The distinctive feature of germination pores, one of which is dorsally positioned near the base of each carpel, indicates that these fruits represent palms rather than a dicotyledonous family. Among extant Arecaceae, closest morphological and anatomical similarities are found among South American representatives of subtribe Attaleinae, within tribe Cocoseae, of the subfamily Arecoideae. These fossils indicate an early presence of Attaleinae in the Old World tropics and relatively rapid intercontinental dispersal in view of the hypothesized South American origin of the clade. Palmocarpon drypeteoides, together with three other palm fruit taxa and abundant vegetative remains previously published from the same beds, indicates that palms were diverse, as well as abundant, in the Ghughua flora of India.

Tracking coarse-grained gravity flows by LASS-ICP-MS depth-profiling of detrital zircon (Aveto Formation, Adriatic foredeep, Italy)

Coarse-grained gravity flow deposits are quite common in the stratigraphic record, but their capability in transporting cobbles and boulders at great distance from the eroding sources is still poorly assessed. Here, we tackle this issue by the analysis of coarse-grained gravity flow deposits of the Aveto Formation, deposited in the Early Oligocene Adriatic foredeep and now exposed in the accretionary wedge of the Northern Apennines (Italy). We combine field observations and provenance constraints provided by Laser Ablation Split Stream (LASS)-ICP-MS depth-profiling of detrital zircon grains. We found that the polymodal grain-age distributions in the analyzed samples, dominated by Periadriatic, Variscan and Caledonian age populations, also include Late Cretaceous to Paleocene ages associated to thin epitaxial overgrowths on older zircon cores. These overgrowths display Th/U and REE patterns consistent with a metamorphic origin, and provide a diagnostic fingerprint that indicates the Bergell area in the Central Alps as the only viable source of coarse detritus, including cobbles and boulders of magmatic and metamorphic rocks, transported by gravity flows towards the nascent Adriatic foredeep. Our results provide not only pin-points for a reliable paleotectonic reconstruction of the Bergell-Aveto source-to-sink system, one of the most remarkable features of the Oligocene Adria-Europe plate boundary, but also compelling evidence for ∼300 km axial transport by gravity flows experienced by coarse detritus derived from the Oligocene Central Alps. The eruptions of the Bergell volcanic complex provided abundant pyroclastic material variably mixed with metamorphic detritus, that was quickly funneled into submarine canyons triggering southward-directed gravity flows. Active tectonics, pyroclastic material provided by volcanic eruptions, steep canyons close to the shoreline and the presence of fault-controlled submarine troughs, may effectively promote the long-distance transport of coarse material by gravity flows not only in the Oligocene, but also today.

Problems of Paleogene–Neogene stratigraphy of the Zerkal’naya depression, East Sikhote Alin

The Paleogene–Neogene stratigraphic scale of the Zerkal’naya River basin is modified with account for new isotopic and paleobotanical data. It is established that the Tadushi Formation and underlying volcanics, which were previously considered as representing transitional Cretaceous–Paleocene strata, are separated in the section of the Ustinovka quarry by a significant stratigraphic hiatus. According to the new data, the volcanics and the Tadushi Formation are established as Campanian and Late Paleocene in age, respectively. The Bogopol Formation in the type section is dated back to the Middle–Late Paleocene. The Svetlyi Formation is now considered to be Early Eocene in age, rather than Late Eocene–Oligocene as previously thought. A new variant of the stratigraphic scale is proposed for the Paleogene–Neogene deposits of the Zerkal’naya depression.

Paleocene–Eocene transition at Naqb Assiut, Kharga Oasis, Western Desert, Egypt: Stratigraphical and paleoenvironmental inferences

This work depends on the study of the lower part of the Esna Formation which encompasses the Paleocene–Eocene (P-E) transition in Egypt as well as at Naqb Assiut section, Kharga Oasis, Western Desert. The Paleocene/Eocene (P/E) boundary is represented by El Dababiya Quarry Member which consists of five distinctive beds (nos. 1–5) at the GSSP. On the other hand, at Naqb Assiut section this boundary is only represented by the upper two beds (nos. 4&5), whereas, the lower three beds (nos. 1–3) are missing due to a hiatus. This hiatus is marked by the occurrence of an irregular surface contains pebbles and phosphatic materials. This hiatus may be related to the echo of Sryian Arc Orogeny at the P/E time. Biostratigraphically; four planktonic foraminiferal zones are defined from base to top as: Acarinina soldadoensis/Globanomalina pseudomenardii and Morozovella velascoensis (late Paleocene), Acarinina sibaiyaensis and Pseudohastigerina wilcoxensis/Morozovella velascoensis (early Eocene). The Acarinina sibaiyaensis Zone which represents the P//E/boundary is characterized by the occurrence of intrazonal hiatus at it's lower part. The benthonic foraminiferal taxa contain abundant representatives of Midway-type fauna (∼91% of the whole assemblages), beside few Velasco-type faunal ones (∼9%), indicating an outer neritic (150–200 m) water depth of deposition during the P–E transition. Quantitative analysis and composition of benthonic foraminiferal assemblages are indicative for various environmental changes around the P/E boundary. They reflected a high diversity, increase of epifaunal taxa, and low-intermediate productivity conditions, which indicates a well-ventilated bottom water and oligo - to mesotrophic conditions during the late Paleocene age. Rapid extinction of about 18% of the entire benthonic foraminiferal species started at the P/E boundary, where the last occurrence of Angulogavelinella avnimelechi is pronounced at the base of this boundary. There is a decline in the preceding faunal characteristics of the late Paleocene and signified an increase in the abundance of agglutinated and buliminid species. These characters are revealed some environmental stressful conditions of low oxygen and increased productivity. During the early Eocene, the environmental conditions are improved leading to the recovery of most benthonic and planktonic foraminifera.

A burrowing frog from the late Paleocene of Mongolia uncovers a deep history of spadefoot toads (Pelobatoidea) in East Asia.

Fossils are indispensible in understanding the evolutionary origins of the modern fauna. Crown-group spadefoot toads (Anura: Pelobatoidea) are the best-known fossorial frog clade to inhabit arid environments, with species utilizing a characteristic bony spade on their foot for burrowing. Endemic to the Northern Hemisphere, they are distributed across the Holarctic except East Asia. Here we report a rare fossil of a crown-group spadefoot toad from the late Paleocene of Mongolia. The phylogenetic analysis using both morphological and molecular information recovered this Asian fossil inside the modern North American pelobatoid clade Scaphiopodidae. The presence of a spade and the phylogenetic position of the new fossil frog strongly support its burrowing behavior. The late Paleocene age and other information suggestive of a mild climate cast doubt on the conventional assertion that burrowing evolved as an adaptation to aridity in spadefoot toads. Temporally and geographically, the new fossil provides the earliest record of Scaphiopodidae worldwide, and the only member of the group in Asia. Quantitative biogeographic analysis suggests that Scaphiopodidae, despite originating in North America, dispersed into East Asia via Beringia in the Early Cenozoic. The absence of spadefoot toads in East Asia today is a result of extinction.

Facies Changes Between Kolosh and Sinjar Formations Along Zagros Fold–Thrust Belt in Iraqi Kurdistan Region

The present study is concerned with lateral and vertical facies changes between Kolosh (Paleocene) and Sinjar (or Khurmala) (Paleocene-Early Eocene) Formations in Sulaimani and Duhok area, Kurdistan Region, NE-Iraq. The latter and former formations are belonging to basinal clastic (turbidite) and reefal carbonate facies respectively. The facies changes are documented in six sections by field studies and evaluation of previous ideas and data which are critically discussed and compared to the result of the present study. The special attention is directed towards the contact between the two Formations in relation to conformity. All the studies achieved before 2002 showed conformable contact between the two formations while the most recent study found large a gap (erosional unconformity) between the two formations which persisted for 5million years. According to latter study, the sea level fall associated with this unconformity assigned to be type one and type two sequence boundaries in the east of Darbandikhan, north of Koya towns and the Bekhme gorge.Conversely, the present study has not recorded gaps in the sedimentation in the studied sections either in Sulaimani or Dohuk area. The contact can be regarded as transgressive system tract which represented by green marl or sandstone, which changes to limestone of Sinjar or Khurmala Formation (HST).The conglomerate beds that are recorded in the previous studies at the contact of the two formations are not proved in the present study. The previously recorded conglomerate is located inside the upper part of the Kolosh Formation not in the contact and it represents submarine fan feeder channel. In contrast to previous studies, neither incised valleys nor erosional unconformity are found at the contact between the two formations in the studied area. The one meter intraformational conglomerate that are found (in some previous studies) in the Bekhme gore is not found in the present study. It is observed that the Kolosh Formation, at Bekhme Gore consists of green marl and sandstone with one bed of Khurmala Formation. The green marl is changes totally to dolomitic limestone of the latter Formation toward northwest at the north of Saru Kani village near Bujeel town. This proves that both formations are deposited in one basin and Khurmala formation has the age of Lower Paleocene to Lower Eocene.

Tectonic variation and structural evolution of the West Greenland continental margin

Because of its geographic extent of over 2500 km (1553 mi), the West Greenland margin provides a much understudied example of a divergent continental margin, both with respect to hydrocarbon exploration and academic studies. A seismic interpretation study of representative two-dimensional reflection profiles from the Labrador Sea, Davis Strait, and Baffin Bay was undertaken to identify sedimentary and structural components to elucidate the tectonic development of the margin. Nine horizons were interpreted from six representative seismic lines in the area. Margin-scale tectono-stratigraphy was derived from isochron maps, the geometry of mappable faults and their associated stratal architecture. Rifting began in Early to Late Cretaceous at ca. 145–130 Ma, which was followed by two pulses of volcanism in Eocene and Paleocene ages. The transition to the drift stage includes a typical subsidence phase but also erosion, uplift, and deposition of Neogene postrift packages. The shift in the position of depocenters in the Davis Strait and the Labrador Sea during Paleocene and Miocene times is evidence for structural modification of the basin bounding faults. Drift stage deformation suggests a possible anticlockwise rotation in the orientation of the spreading axis in Baffin Bay culminating in an ultraslow sea-floor spreading. Sea-floor spreading on the West Greenland margin started in the south at 70 Ma in the Labrador Sea and propagated northward into the Baffin Bay by 60 Ma. Prospective petroleum systems include thick Cretaceous age strata, with structural traps provided by grabens and inversion structures. Our structural model provides insight into a margin that is highly variable in its structural configuration, further modified by other processes such as magma-assisted rifting that may result in elevated regional heat flow, which has considerable impact on hydrocarbon maturation. Further constraining the implications of heat flow associated with volcanic activities in comparison to that associated with lithospheric stretching will be critical in future exploration.

Discussion of Jamaican Cenozoic ichnology: review and prospectus: (v. 50, pp. 364–382)

We make two comments on the paper ‘Jamaican Cenozoic ichnology: review and prospectus’ by Donovan et al. (2015). Based on biostratigraphy and new radiometric dates, we recommend the separation of the Richmond Formation (deposited in the Wagwater Graben and onlapping onto the edges of the Clarendon Block and Blue Mountains Block) and the Moore Town Formation (deposited in the John Crow Mountain Graben) which are of early Eocene and early Paleocene age, respectively. The ichnofossils of the Scolicia ichnocoenesis are different in the two basins. We also point out that extensive borings recorded from the late Eocene Somerset Formation of the White Limestone Group most probably came from the late Oligocene Walderston Formation. Copyright © 2015 John Wiley & Sons, Ltd.

Calcareous Nannofossils Events of Nephrolithus Frequens Zone to Markalius Inversus Zone in Section of Kazerun, Zagros (Iran)

One of the most complete Late Maastrichtian to Early Danian sequences contains the Kazerun section of West Fars Province, Zagros basin of Southwestern Iran. The present investigation identifies index species, 15 Genera and 22 Species of nannofossils in this boundary. Calcareous nannofossils, which observe in Cretaceous-Paleogene boundary strata, are believed to be appropriate means for biostratigraphical study. The majority of Cretaceous-Tertiary boundary (K/Pg) strata are made up of grey shale and then purple shale, respectively. The acquired nannofossils show continuity in K/Pg boundary in Western part of Fars Province. This agrees with the existence of Nephrolithus frequens zone, which predicts the age of late Late Maastrichtian and Markalius inversus zone which describes the age of Early Paleocene (Early Danian). Also, the examination of calcareous nannofossils of the Kazerun section at Zagros basin enabled us to recognize standard biozones defined in Mediterranean regions, especially Tethysian domain.

Larger Benthic Foraminifera from the Paleocene Sediments in the Chehel-Kaman Formation, North-Eastern Iran

This study is the micropaleontological investigation of the Chehel-Kaman Formation of Paleocene age from Kopet-Dagh basin, NE of Iran. Thirty three species of diagnostic benthic foraminifers belonging to genera Miscellanea,Operculina, Lockhartia, Rotalia, Akbarina, Pseudocuvillerina, Smoutina,Davisina, Idalina, Valvulina, Laffitteina, and Ranikothalia are recorded based on detailed petrographic analysis. The rocks are entirely shallow marine in rigin with biotic assemblages confirming Chehel-Kaman Limestone of the Paleocene age. The analyses of benthic foraminifers suggest that the deposition of the Paleogene sequence occurs in warm and shallow marine environments. In this paper Ranikothalia sindensis partial zone was reported in association withMiscellanea miscella, M. juliettae and M. yvettae.

Sedimentary successions and palynoevent stratigraphy from the non-marine Lower Cretaceous to the marine Upper Cretaceous of the Nuussuaq Basin, West Greenland

Abstract The Nuussuaq Basin, West Greenland, comprises the only exposures of Mesozoic sedimentary strata on the west coast of Greenland. The Nuussuaq Basin exposes Cretaceous and Paleocene siliciclastic strata, referred to as the Nuussuaq Group, overlain by volcanic rocks, mainly of Paleocene age, referred to as the West Greenland Basalt Group. Regional seismic studies indicate that the Cretaceous strata of the Nuussuaq Basin may be correlated to the Appat and Kangeq seismic sequences in the offshore basins. The present paper re-investigates five profiles, trending roughly east-west, from northern Disko to southern Svartenhuk Halvo, which exemplify the litho- and biostratigraphy, with a focus on the pre-Campanian deposits. The oldest exposed strata belong to the non-marine Kome Formation of possible Albian age. Dinoflagellate cysts that indicate brackish water conditions characterize the Albian and early Cenomanian, whereas marine dinoflagellate cysts occur in the latest Cenomanian, and in younger deposits. The dating of the Nuussuaq Group is based mostly on palynology, supported by scarce ammonites. A new, refined palynoevent stratigraphy is established, based on the study of many new and older sections. The new palynoevent stratigraphy allows a better correlation between widely spaced onshore sections and offshore successions, and provides an improved basis for paleogeographical interpretations.

Stratigraphy and depositional history of the Cretaceous carbonate successions in the Spil Mountain (Manisa, W Turkey)

The Bornova Flysch Zone (western Turkey) consists of huge Mesozoic limestone and ophiolite blocks embedded into sheared siliciclastic sedimentary rocks of Maastrichtian−Paleocene age. The limestone blocks, which range in age from Late Triassic to Cretaceous, are considered to be olistoliths or deformed and sliced platform parts. In the Spil Mountain, two successions of Cretaceous carbonates are tectonostratigraphically differentiated: (1) a Lower Cretaceous and Campanian(?)−Maastrichtian relatively autochthonous succession showing sedimentary transition to the Bornova Flysch, and (2) a Cenomanian(?)−lower Campanian allochthonous succession overthrusted to the flysch. These successions represent separate parts of the same platform. The autochthonous succession bears Lower Cretaceous peritidal carbonates at its base and is named Unit 1. The succession is often composed of fenestral mudstone and algal wackestone microfacies. Unit 2 disconformably overlies Unit 1 and consists of platform-derived litho and bioclastic packstones of Campanian(?)−Maastrichtian age. This unit reveals a typical thinning and fining upward sequence, finally passing into pelagic wackestones of Unit 3. The two aforementioned units record a platform drowning event, which occurred rapidly based on the presence of planktonic foraminifera within matrix of basal breccia. Carbonate deposition ceased due to the input of siliciclastic sediments during the late Maastrichtian−Paleocene. The allochthonous succession consists of two vertically superimposed units: (1) Cenomanian(?)−Santonian rudistid limestones (Unit 4) deposited in restricted platform environments and (2) Santonian−lower Campanian pelagic limestones (Unit 5) indicating open platform to slope conditions. The Spil Mountain Cretaceous carbonate sequences are correlated with those in peri-Mediterranean platforms. They show close similarities to the Bey Dağları (western Taurides) carbonate sequences in stratigraphy and facies. Paleontological and sedimentological analyses and the microfacies enable us to reconstruct a paleoenvironment evolution and a facies model for the Spil Mountain carbonate deposits during the Cretaceous period.