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A Revised Cenozoic Geochronology and Chronostratigraphy
Abstract
Since the publication of our previous time scale (Berggren and others, 1985c = BKFV85) a large amount of new magneto- and biostratigraphic data and radioisotopic ages have become available. An evaluation of some of the key magnetobiostratigraphic calibration points used in BKFV85, as suggested by high precision 40Ar/39Ar dating has served as a catalyst for us in developing a revised Cenozoic time scale. This paper presents a revised (integrated magnetobiochronologic) Cenozoic time scale (IMBTS) based on an assessment and integration of data from several sources. Biostratigraphic events are correlated to the recently revised global polarity time scale (CK95). The construction of the new GPTS is outlined with emphasis on methodology and newly developed polarity history nomenclature. The radioisotopic calibration points (as well as other relevant data) used to constrain the GPTS are reviewed in their (bio)stratigraphic context. An updated magnetobiostratigraphic (re)assessment of about 150 pre-Pliocene planktonic foraminiferal datum events (including recently available high southern (austral) latitude data) and a new/modified zonal biostratigraphy provides an essentially global biostratigraphic correlation framework. Finally, the current status of Cenozoic chronostratigraphy is reassessed and estimates of the chronology of lower (stage) and higher (system) level units are presented. -from Authors
... The procedure included indexing of chert sections recognized via searching the open-access database for the EP ODP and DSDP wells. Each of these chert (and/or porcellanite) sections was assigned a numerical age span utilizing biozonations of Okada and Bukry (1980), Berggren et al. (1995), and Kamikuri et al. (2012a, b) (Table 1; Fig. 2A). The chert intervals overlapping in age were then added-up together. ...
... Negative longitudes and latitudes indicate °W and °S, positive longitudes and latitudes being °E and°N. Standard calcareous nannofossil biozonations (Nannoplankton Neogene (NN) Zones, Nannoplankton Paleogene (NP) Zones, Coccolithus Neogene (CN) Zones, and Coccolithus Paleogene (CP) Zones) were adapted from Martini (1971) and Okada and Bukry (1980), foraminiferal zones (Neogene (N) and Paleogene (P)) from Berggren et al. (1995), and radiolaria biozones (Radiolarian Neogene (RN) and Radiolarian Paleogene (RP)) from Sanfilippo and Nigrini (1998) and Kamikuri et al. (2012b). The younger (Min = minimum) and older (Max = maximum) limit ages, the mean age, and the duration of chert intervals were derived based on these assigned biozones. ...
... Following interrogation of DSDP and ODP databanks for the selected EP sites, 58 chert and porcellanite age intervals were archived, with a numerical age domain, defined based on biozonal indicators of Okada and Bukry (1980), Berggren et al. (1995), Sanfilippo and Nigrini (1998), and Kamikuri et al. (2012a, b) allocated to each interval (Table 1; Fig. 2A). A summing up proceeding was pursued for intervals overlapping in age, and extension of this scheme to all 58 catalogued chert age segments generated a total of 91 time slices dispensed from 0.8 to 68 Ma. ...
Biosiliceous cherts hosting the transformation of biogenic silica to paracrystalline opal-CT, deposited in the low-latitude realms of Jurassic to Neogene, were recently interpreted as developing during episodes of elevated primary productivity along upwelling areas in equatorial and sub-equatorial paleo-latitudes. Geographically widespread distribution of chert and other rock types of biosiliceous origin, including porcellanite and siliceous claystones throughout the Eocene however indicates these diagenetic deposits are not in any case the dependable markers of latitude-driven upwelling regimes. This study aims to explore the dominance of early Eocene chert occurrences in the Equatorial Pacific (EP) sediments, and their contribution to the Cenozoic global climate change. Our new assessment of the age-abundance dispersal of EP Cenozoic chert sections accommodated by Deep Sea Drilling Project (DSDP)- and Ocean Drilling Program (ODP)-cored deposits realized that the cherts transformed from deposited opal-A sediments most commonly in the early Eocene, with a peak in abundance at ∼50 Ma. This age interval of significant chert occurrences coincided with the period of seawater-temperature maxima of the early Eocene climatic optimum (EECO), during which the world ocean was supposedly marked by highly reduced upwelling intensity and siliceous bioproduction. The spatio-temporal distribution model of the EP Cenozoic cherts with the peak occurrences during the EECO presented in this study bears close similarities to the global distribution patterns of chert during the Cenozoic, which strongly correspond to a global paleoclimatic driver rather than upwelling regimes. Following our survey, cherts occurred less frequently in the post-early Eocene, which is characterized by cooling bottom waters and amplified upwelling and bioproductivity. This model suggests the paleo-seawater rich in dissolved silicon (DSi) would have been imperative for peak incidences of early Eocene chert production, despite extreme surface warmth and greenhouse conditions of the EECO, making DSi available to opal-secreting phytoplankton via deep-water ventilation. These imply that the paleo-climate was more impactful to diagenetic chert production than latitudinally mediated ocean upwelling. The chert distribution events during the early Eocene reduced siliceous bioproductivity appear to have been insufficient to compensate for the significant silica input to the basin mainly from climate-controlled continental weathering. The DSi uptake by precipitation of authigenic clays which accompanies opal-A diagenesis in many depositional systems has been operative, with higher rates in carbonate- than clay-dominated sediments, so as to sustain balance between DSi released to the ocean from terrestrial sources and the silica expelled in sediments during the EECO weakened upwelling.
... Biostratigraphic studies on these two formations have primarily been based on Wynd (1965), which is mostly local, and comprehensive biostratigraphic zoning based on the standards introduced in the Tethys basin has not yet been defined for them. Many biostratigraphic studies have effectively characterized the upper Cretaceous-Paleogene biostratigraphy, e.g., Berggren et al. 1995;Premoli Sliva and Verga 2004;Berggren and Pearson 2005;Wade et al. 2011;Coccioni and Premoli Silva 2015, leading to improved local stratigraphy and valuable age determinations for the geologic time scale. The biostratigraphic studies on the two mentioned formations have mainly relied on a local biozonation (Wynd 1965), which cannot correlate with global biozonations (Fig. 1b). ...
... The Zagros belt is divided into five main sub-parallel distinct provinces Fig. 1 a A generalized lithostratigraphic chart for Southwest Iran, depicting stratigraphic units spanning from the late cretaceous (specifically the maastrichtian stage) to the paleogene, modified from James and Wynd (1965) and Motiei (1995). b Biozonation of Khuzestan, Lurestan, and Fars area (Wynd 1965); c Stratigraphic correlation between the Tange-Lendeh and the Genave-Lori sections; d global depositional depths of K/Pg boundary sections and the location of the Izeh Zone within the Zagros mountains (adaptation from Keller 1996) The biostratigraphic interpretations of the Paleogene were based on established schemes (Berggren et al. 1995;Berggren and Pearson 2005;Wade et al. 2011), while interpretations for the upper Cretaceous relied on Premoli Silva and Verga (2004). The identification of Planktic foraminifera genera and species drew from various sources (Postuma 1971;Olsson et al. 1999;Premoli Silva et al. 2003;Berggren and Pearson 2006;Robaszynski and Caron 1984;Premoli Silva and Verga 2004), spanning the Maastrichtian to the Paleogene. ...
... The identified planktic foraminiferal species in this zone include Acarinina strabocella, Chiloguembelina sp., Globanomalina compressa, G. chapmanii, Igorina albeari, I. tadjikistanensis, I. pusilla, Morozovella praeangulata, M. pasionensis, M. acutispira, M. apanthesma, M. conicotruncata, Praemurica inconstans, Subbotina triloculinoides, S. triangularis, S. velascoensis. The assemblage is recognized as being of a middle Paleocene (Selandian) age and equivalent to subzone P3b of Berggren et al. (1995) Berggren and Pearson (2005). ...
The sedimentary sequence, extending from the Maastrichtian to the lower Eocene and exposed in two sections in the easternmost part of the Izeh Zone (Kuh-e-Sefid and Mish anticlines) in the Zagros Basin, has been subjected to a comprehensive analysis of its Planktic foraminiferal assemblage. This time interval encompasses the upper part of the Gurpi Formation and the lower to middle part of the Pabdeh Formation, spanning from the base to the top. The lithology of the Maastrichtian-early Eocene successions comprises calcareous shales, argillaceous limestones, glauconitic and phosphatic limestones, marlstones, purple shales, and cherty argillaceous limestones. A total of 35 genera and 118 species of Planktic foraminifera have been conclusively identified. The identified biozones include the Contusotruncana contusa Interval Zone and the Abathomphalus mayaroensis Interval Zone, indicating an early to late Maastrichtian age for the upper part of the Gurpi Formation. The lower to middle part of the Pabdeh Formation exhibits distinctive biozones, such as Praemurica uncinata (P2), Igorina albeari (subzone P3b), Igorina-Globanomalina pseudomenardii Interval Zone, Globanomalina pseudomenardii (P4), Morozovella velascoensis (P5), Acarinina sibaiyaensis (E1), Globanomalina pseudomenardii-Pseudohastigerina wilcoxensis Interval Zone, Pseudohastigerina wilcoxensis/Morozovella velascoensis (E2), Morozovella marginodentata (E3), Morozovella velascoensis-Morozovella formosa formosa and/or Morozovella lensiformis Interval Zone (subzone P6a), Morozovella formosa (E4), Morozovella aragonensis/Morozovella subbotinae (E5), Acarinina pentacamerata (E6), Acarinina cuneicamerata (subzone E7a), and Turborotalia frontosa (subzone E7b). The boundary between the Pabdeh and Gurpi Formations in the examined sections is demarcated by an unconformity, characterized by a sedimentary hiatus from the early Danian to the early Selandian within biozones P0 to P3a.
... For planktonic foraminifera, the taxonomy of Toumarkine and Luterbacher (1985), , and Pearson and Wade (2015) were used. Tropical to subtropical planktonic foraminifera biozones were defined according to Berggren et al. (1995), Berggren and Pearson (2005), and Wade et al. (2011). Images of selected gold-coated planktonic foraminifera were obtained by Scanning Electron Microscopy (SEM model FEI NOVANANOSEM 650). ...
... The basal part of the section is a yellowish fine-grained sandstone, siltstone, and claystone with a thickness of about 4 m and is overlain by an alternation of grayish claystone and marl units in the upper part of the section. The Globigerinatheka kugleri/ Morozovella aragonensis Concurrent-range Zone [Zone E9 of Berggren and Pearson (2005) and Wade et al. (2011); Zone P11 of Berggren et al. (1995)] is Lutetian in age and was identified from the bottom of the section to the last occurrence of Morozovella aragonensis (13.5 m, Sample no. 10). ...
... mexicana, H. liebusi, H. nuttalli, H. dumblei). The highest consistent occurrence of Guembelitrioides nuttalli, marking the top of the Acarinina topilensis Partial-range Zone [Zone E10 of Berggren and Pearson (2005) and Wade et al. (2011); lower part of Zone P12 of Berggren et al. (1995)], is recorded at 21 m (sample no.15). Acarinina bullbrooki, A. collactea, A. praetopilensis, Morozovelloides crassatus, M. coronatus, and M. lehneri were observed in abundance in Zone E10. ...
The Kayikoy Formation (Isparta, SW Turkiye) consisting of sandstone, claystone, and marl units contains abundant, low-moderate preserved, and diverse planktonic foraminifera assemblages. Eight planktonic foraminiferal biozones (E9-E16) were determined encompassing the Lutetian-Priabonian stages (middle-upper Eocene) by using the biostratigraphic distributions of 17 genera and 62 species of planktonic foraminifera. Stable delta 18O and delta 13C isotope values were measured for 53 individuals belonging to Morozovelloides crassatus, Acarinina bullbrooki, A. topilensis, A. echinata, Globigerinatheka curryi, G. index, G. subconglobata, G. mexicana, G. barri, G. euganea, Orbulinoides beckmanni, Turborotalia frontosa, T. pomeroli, Hantkeninamexicana, H. liebusi, H. dumblei, H. alabamensis, and Dentoglobigerina eotripartita. By integrating planktonic foraminiferal biostratigraphy, stable delta 18O and delta 13C isotopes, and paleotemperature analyses, the first detailed study of the Middle Eocene Climatic Optimum (MECO) record was performed in SW Anatolia/Turkiye. The overall signature of the MECO is similar to global observations but also involves some regional differences. The MECO paleotemperatures, determined to vary between approximately 2 degrees C and 5 degrees C, were similar to the global records, but the slight differences in values in the three sections are most likely due to the paleogeographic position of the studied section in Turkiye.
... 8,9). The Paleogene planktonic foraminifera zonal scheme (P) which is followed is that of Berggren et al., (1995). (Blow), Acarinina angulosa (Bolli). ...
... (Blow), Acarinina angulosa (Bolli). Correlation: This zone correlatable with the Morozovella aragonensis Zone of Bolli (1966), Toumarkine and Luterbacher (1985) and Berggren et al., (1995), it is also equivalent to the Globorotalia aragonensis Zone of Berggren (1969), Stainforth et al., (1975), Elewi (1982).These zones are assigned to the Early Eocene. (Blow). ...
... (Blow). Correlation: The present zone is equivalent to the same zone of Bolli (1966), Bolli and Krasheninnikov (1977) and Toumarkine and Luterbacher (1985), it is correlated to the Globorotalia pentacamerata of Elewi (1982),it is also equivalent to Acarinina pentacamerata Zone recorded in Iraq by Al-Mutwali (1992) Bolli (1966), Toumarkine and Luterbacher (1985), Berggren et al. (1995) and Berggren and Pearson (2005), it is also equivalent to the Hantkenina aragonensis Zone of Berggren (1966). Stainforth et al., (1975) and Bolli and Krasheninnikov (1977). ...
... Fig. 4 represents a composite range chart for the studied wells and provides the stratigraphic distribution of most recovered foraminiferal species (Plates 1-6). The results were analyzed to have a biostratigraphic control based on the planktic foraminiferal zones of Berggren et al., (1995) for the Palaeocene sequence. The recovered larger benthic foraminifera from the Late Palaeocene to Miocene were examined biostratigraphically according and assigned to the shallow benthic zones (SBZ) of Cahuzac and Poignant, (1997) and Serra-Kiel, et al., (1998). ...
... The shale is dark grey to black with abundant planktic foraminifera. The recovered fauna from this unit (Fig. 4) Berggren et al. (1995). This zone has been subdivided into three subzones (P1a-P1c) based on the chronological appearances of Subbotina triloculinoides and Globanomalina compressa/Praemurica inconstans (Berggren and Miller, 1988). ...
... A similar conclusion has been reached for the overlying P1c subzone. The remaining time-interval of the Danian Stage is considered belonging to the P2: Praemurica uncinata-Morozovella angulate Interval Zone of Berggren et al. (1995). The biostratigraphic interval between the FAD of Praemurica uncinata and the FAD of Morozovella angulate can be recognized in Fig. 4. Berggren et al. (1995). ...
Palaeocene to Miocene planktic and larger benthic foraminifera retrieved from ditch cuttings samples taken from 5 wells drilled in Concession 65, SE of Sirt Basin, Libya, have been studied biostratigraphically. This study indicates that the Palaeocene sequence is composed of a shale unit overlain by a carbonate unit. The shale unit contains a rich assemblage of planktic foraminifera indicating Early Palaeocene age (Danian Stage), which is equivalent to the planktic foraminiferal zones P1 and P2. The overlying carbonate unit is Late Palaeocene in age (Selandian-Thanetian) based on the occurrence of several planktic foraminiferal species of the planktic foraminiferal zones P3-P5. The recovery of few species of larger benthic foraminifers from this carbonate unit provides an additional evidence that it was deposited during the Late Palaeocene, corresponding to the shallow benthic foraminiferal biozones SBZ3-SBZ6, which correspond to the (Selandian-Thanetian) stages. The Early Eocene sequence is mainly barren anhydrites and dolomites with rare badly preserved nummulitids in the Ypresian. The Middle Eocene (Lutetian-Bartonian) limestones contain a nummulitic assemblage with variable species, including Nummulites gizehensis/Nummulites lyelli group, which represent the SBZ14-SBZ16 in the Lutetian and the SBZ17-SBZ18 in the Bartonian. The Late Eocene interval is dated on the presence of few reticulate medium-sized nummulitic species, including Nummulites fabianii, and assigned to the SBZ19. The lowermost part of the Oligocene sequence is attributed to the SBZ21 (Rupelian) based onthe occurrence of Nummulites vascus and Operculina complanata in the limestones. This is overlain by the SBZ22 (Chattian), as indicated by the last occurrence of Nummulites vascus and the first appearance of Borelis melo melo and Amphistegina sp. The uppermost deposits of the studied successions, which are mainly sandstones with hardly any fossils, belong to the Miocene.
... The SB zones for the Paleocene and Eocene were correlated by Serra-Kiel et al. (1998) to the timescale given by Berggren et al. (1995), using magnetostratigraphy and standard planktic microfossil zonations but, as the authors themselves specified, these correlations were susceptible to be modified according to the future advances of the biostratigraphic knowledge. Recently, some updates (e.g., Scheibner and Speijer 2009;Mochales et al. 2012;Rodríguez-Pintó et al. 2012Costa et al. 2013) to the correlations scheme for the Paleocene and the Eocene were summarized by Papazzoni et al. (2017a) and some advances have been achieved (e.g., Cotton et al. 2017;Papazzoni et al. 2017b;Özcan et al. 2019;Luciani et al. 2020;Serra-Kiel et al. 2020;Zakrevskaya et al. 2020). ...
... 3B) shortly below the first occurrence of the orthophragminids which marks the base of SB3. The top of F. pileatus, although not used in the zonal schemes, is largely documented and well calibrated in the literature (e.g., Backman 1986;Rea et al. 1993;Berggren et al. 1995;Agnini et al. 2007a). Specifically, Berggren et al. (1995, p. 177) associated the event to the middle part of Chron C26r as well as Agnini et al. (2007b). ...
... 14), suggesting that the event is synchronous between the two compared sections. Once it has been ascertained that the three considered events are synchronous, the age of the orthophragminids B has been indirectly assumed by means of the mean accumulation rate calculated between the calcareous nannofossil events whose ages have been calibrated in Agnini et al. (2014;for F. tympaniformis B) and in Berggren et al. (1995; for F. pileatus T). The estimated age of orthophragminids B is 58.82 ...
Three key Paleocene deep-sea sections cropping out in northern Italy contain intercalations of calciturbiditic, larger foraminifera-bearing beds derived from shallow water environments. The reconstructed Southern Alps record obtained by splicing the
three sections allowed a direct correlation of the shallow benthic SB and calcareous nannofossils CN Zones, leading new data about the Shallow Benthic biozonation for the Danian-Thanetian interval and proposing four new SBP (Shallow Benthic Paleocene) Zones (SBP1-4). Such revision relies on an innovative biostratigraphic approach based on larger foraminiferal biohorizons instead of marker species according to the traditional approach used since the introduction of the SB Zones. Based on our study, the SBP1/SBP2 boundary turns out to be about 2 Ma after the K/Pg crisis, highlighting a quite fast recovery of the complexity among foraminifera.
... The foraminiferal species were illustrated using a Scanning Electron Microscope (SEM) from Al-Azhar University's Regional Center for Mycology and Biotechnology. To analyze planktic foraminifera, a combination of biostratigraphic schemes developed by Berggren et al. (1995), Lourens et al. (2004), and Wade et al. (2011) were used. ...
... Our hypothesis was based on the first common occurrence (FCO) of Trilobatus primordius, documented at depth 2728 of the RUDEIS-4 borehole. This bioevent was placed within the Chattian O7 Zone by Leckie et al. (1993), Berggren et al. (1995), and Wade et al. (2011). Also, this depth interval contains small Ciperoella ciperoensis, indicating an Oligocene Epoch assignment to these smaller specimens, as suggested by Bolli (1954). ...
The Nukhul Formation represents the sediments deposited during the earliest phase of the syn-rift period in the Gulf of Suez rift. It is the primary hydrocarbon reservoir for fifteen fields in the region. However, the timing of rifting needs to be better constrained, and the influence of local tectonics and global eustatic sea-level fluctuations on reservoir quality and deposition is still being determined. This research aims to establish a stratigraphic sequence framework, determine the age of the Suez Rift commencement, use changes in paleobathymetry, and assess reservoir quality. The methods employed involve the analysis of four boreholes in the Abu Rudeis-Sidri field, incorporating biostratigraphy, well-logs, and 3D seismic data. The integrated paleo-structure and biostratigraphic analyses indicate that the beginning of rifting in the Gulf of Suez occurred at 23.53 Ma at the first common occurrence (FCO) of Trilobatus primordius. The paleobathymetric analysis of the Nukhul Formation reveals deeper paleo-water depths during certain intervals, indicating deposition during a phase of high subsidence and rift-climax. The Nukhul stratigraphic sequence reflects sea-level changes leading to shifts in accommodation , and facies changes, erosion, and sequence formation during the late Chattian and early Burdigalian stages. However, the reservoir characterization of the Nukhul Formation is significantly affected by various factors, including cementation, pore system properties, sediment sorting, rift system geometry, and relative sea-level fluctuations. These factors must be carefully considered in any regional exploration or development efforts. The study also reveals that tectonic activity played a role in forming fault-bounded basins, and eustatic sea-level changes influenced the rate and timing of sediment accumulation. These findings can aid in predicting the distribution of the Nukhul sedimentary deposits and improve the ability to explore and develop their resources.
... A new high-resolution study of Eocene-Oligocene "U-channel" samples from this site presents high correlation with the GPTS (Florindo and Roberts, 2005). Ocean calcareous nannofossil datums (Wei and Wise, 1992;Wei, 1992, Persico and Villa, 2002, 2004, planktonic foraminiferal datums (Kennett and Sott, 1990;Thomas, 1990;Berggren et al., 1995) and Argon-argon ( 40 Ar/ 39 Ar) dating (Glass et al., 1986;Vonhof et al., 2000) is used to re-calibrate ages for this site. ...
... A high-resolution magnetostratigraphic study from ODP Site 748B was carried out by Roberts et al. 2003 in continuous "U-channel" samples, revising the shipboard analysis from Inokuchi and Heider, 1992 biostratigraphy (Aubry 1992), planktonic foraminiferal biostratigraphic datums (Berggren et al., 1995), diatom datums Barron, 1991, Roberts et al., 2003) and strontium isotopes ages (Zachos et al., 1999;Roberts et al., 2003) were re-evaluated for a better age model. ...
The Eocene-Oligocene transition (ca 40-33 Ma) marks a transformation from an ice free to an ice-house climate mode that is well recorded by oxygen stable isotopes and sea surface temperature proxies. Opening of the Southern Ocean gateways and decline in atmospheric carbon dioxide have been hypothesised as possible triggers of the major climate shift during the Cenozoic. However, the identification of the driving mechanisms remains controversial and it depends on a better understanding of how the different environmental changes correlate to each other. In this study, we investigate the spatio-temporal variation in export productivity using biogenic Ba (bio-Ba) from different Ocean Drilling Program (ODP) Sites in the Southern Ocean, focusing on possible mechanisms that controlled them as well as correlation of export productivity changes to changes in the global carbon cycle. We document two significant SO region high export productivity late-Eocene events (ca. 37 and 33.5 Ma) that are correlated to pronounced changes in global atmospheric pCO2. We propose that paleoceanographic changes that followed Southern Ocean gateway openings, along with more variable increases in circulation driven by episodic expansion and decline of the Antarctic ice sheet, drove enhanced SO export production in the late Eocene through basal Oligocene. These factors may have driven the episodic reduction of atmospheric carbon dioxide and contributed to Antarctic glaciation during the Eocene-Oligocene transition.
... S5), were the Praeorbulina and Orbulina species show the highest amounts of individuals, we were able to identify three planktic foraminifera zones. The complete absence of the genera Praeorbulina and Orbulina indicates a Karpatian age (planktic foraminiferal zone M4, Berggren et al., 1995 Wade et al., 2011;Raffi et al., 2020). This gap might cover a much wider interval since the exact amount of missing M4-and M5b-sediments is not known. ...
... In addition to the specimen analysed from the residue splits, Praeorbulina glomerosa glomerosa was found in samples 7.5 m, 17.1 m, and 18.2 to 19.0 m, as well as Praeorbulina glomerosa circularis in samples 18.2 and 19.0 m. Planktic foraminiferal zones according toBerggren et al. (1995) Chronostratigraphic ranges of foraminiferal and calcareous nannofossil index species in the Central Paratethys applied in this contribution (based on ...
The Krems Embayment contains the westernmost fully marine depositional environments of the Karpatian and Bade-nian transgressions in the Central Paratethys. Four drill cores were investigated to analyse the bio- and lithostratigraphic, and tectonic relations. The investigated core sections cover the Karpatian Laa Formation (bio-zones M4, NN4) and the Badenian Gaindorf Formation (M5b-M6, NN4-NN5). Important biostratigraphic indicators identified are Praeorbulina glomerosa glomerosa, Praeorbulina glomerosa circularis and Orbulina suturalis for the Gaindorf Formation. The Laa Formation is indicated by the absence of Praeorbulina , Orbulina and Globigerina falconensis , low numbers of Globorotalia bykovae , and a prominent peak in Helicosphaera ampliaperta abundance at the end of the Karpatian. Cibicidoides lopjanicus and Cassigerinella spp. occur with high percentages in Badenian samples and show much longer stratigraphic ranges than known from literature data. The depositional gap at the Karpatian-Badenian boundary has a minimum duration of 0.41 My in the Krems Embayment. The combination of bio- and lithostratigraphic data allows the correlation across major faults. The Diendorf-Boskovice Fault System played an important role during basin formation and was identified as very active during the early to middle Badenian Stage. The results of this study show the complex interaction of sedimentation, tectonic activity and paleobiological developments in this peripheral part of a marginal sea.
... Thus, 97 measurements of striated fault planes and joints were carried out in seven selected sites of the Late Miocene exposures in the Cap Bon Peninsula, Saouaf, Monastir, Jemmal, Zeramdine, and Ksour Essaf (Fig. 1). Table 1 Berggren et al. (1995) and Frigui et al. (2016). Eustatic and relative sea-level changes after Haq et al. (1988). ...
... Eustatic and relative sea-level changes after Haq et al. (1988). This paper refers to the time scale of Berggren et al. (1995). Planktonic forams are from Hooyberghs (1987Hooyberghs ( , 1995, Besème & Blondel (1989), Hooyberghs & Ben Salem (1999), and Moissette et al. (2010). ...
The tectonic inversion of the Miocene extensional basins (Cap Bon Peninsula-Sahel area, northeastern Tunisia) is an important process that accommodates the crustal shortening in the northeastern Tunisian edge with the ongoing collision between the African and European plates. Field observations and microtectonic measurements have revealed two main Late Miocene tectonic events: (1) A NE-SW trending extensional tectonic event that would create titled blocks, horsts, and grabens, as well as slump features. These structures were controlled by numerous conjugate systems of syndepositional normal faults. On a regional scale, the NW-trending faults controlled the Miocene sedimentation and subsidence rate in the Takelsa, Dakhla, Saouaf, and Zeramdine syn-rift grabens and (2) the NW-directed post-Tortonian compression, the so-called "Alpine/Atlasic event" that was identified by NE-SW-oriented reverse slip movements and associated folds. The latter compressional event began in the latest Miocene and continued through the Plio-Quaternary, which thus led to the complete inversion of the Miocene basins by the ongoing African and European plates' convergence. A significant neotectonic uplift of the Abderrahmane, Korbus, and Skanes areas recorded the switch from Late Miocene crustal extension to post-Tortonian to Quaternary compressional tectonics. In fact, the present-day petroleum trap configuration of the northeastern offshore Tunisia is highly controlled to the Miocene-Quaternary tectonic inversion. The sandy levels along the thick Tortonian section provided the most preferred target for petroleum exploration. They exhibit considerable variations in thickness controlled by Late Miocene to Quaternary tectonic trends.
... Leonov and Alimarina (1961) introduced Globorotalia (Turborotalia) pseudobulloides-Globorotalia daubjergens, later Bolli (1966) renamed as Globigerina pseudobulloides PRZ. Berggren and Miller (1988) and Berggren, et al. (1995) Sharbazheri, Ghafor and Muhammed (2009; and Al-Nuaimy, et al. (2020). It is also comparable with the global record of this zone (Fig. Correlation). ...
The present study interprets the high resolution of the biostratigraphy across the Cretaceous/Paleogene (K/Pg) boundary from Sulaymaniyah, Kurdistan Region, and northeast Iraq, based on planktic foraminifera. The Dartw section was selected for this study, within the High Folded Zone. The biozone contact consists of lithostratigraphic resemblance and is represented by the upper part of the Tanjero Formation (late Maastrichtian) with the overlying Kolosh Formation (Danian). Four late Maastrichtian planktic foraminiferal biozones have been recorded from the Tanjero Formation: Racemiguembelina fructicosa Interval Zone (CF4), Pseudoguembelina hariaensis Concurrent Range Zone (CF3) , Pseudoguembelina palpebra Partial Range Zone (CF2), and Plummerita hantkeninoides Total Range Zone (CF1), while three Danian planktic foraminiferal biozones and two subzones have been recorded from the Kolosh Formation: (Guembelitria cretacea (P0) Interval Zone, Parvularugoglobigerina eugubina (Pα) Total Range Zone, and Parasubbotina pseudobulloides (P1) Partial-Range Zone (Globoanomalina archaeocompressa (P1a) Partial Range Subzone, and Subbotina triloculinoides (P1b) Interval Subzone). High biostratigraphic resolution indicates a complete K/Pg transition with no hiatus at the studied section in the Sulaymaniyah area. The ranges of the species recognized in this study are given. Correlations with other sections in Iraq and other parts of the world, including the type Maastrichtian and Danian areas, are discussed and represented in correlation charts, together with the ranges of the important Upper Maastrichtian and Paleocene species. Index Terms-High Resolution, K/Pg boundary, Kurdistan region of Iraq, Planktic Foraminifera.
... All the biostratigraphic data included herein come from previous works Bosio et al., 2020c;Di Celma et al., 2022). However, First Occurrences (hereinafter: FO) and Last Occurrences (hereinafter: LO) were originally calibrated to the Berggren et al. (1995) timescale and are now referred to the Supporting Information of Lazarus et al. (2014), which provides recalibrations to the more recent timescale by Gradstein et al. (2020). Consider, however, that most of the bioevents were originally calibrated for the North and Equatorial Pacific. ...
The previously scarce fossil record of Ziphiidae (beaked whales) has greatly increased recently thanks to the serendipitous discovery of high specimen concentrations along deep seafloors as well as to abundant inland finds from the Upper Miocene of the Pisco Formation (East Pisco Basin, Peru). In the latter unit, ziphiid remains are indeed among the most prevalent of the whole cetacean assemblage, being represented by four distinct genera and species plus at least two as-yet unnamed taxa. Here, we describe a fifth ziphiid genus and species from the Pisco strata, Mamaziphius reyesi n. gen. n. sp., based on a partial cranium from mid-Tortonian (lower Upper Miocene, 9.1-9.0 Ma) strata exposed at the locality of Cerros la Mama y la Hija. Though reminiscent of the extant genus Berardius, the holotype skull lacks two diagnostic characters of Berardiinae, namely, an isolated rounded protuberance formed by the interparietal or frontals on the posterior part of the vertex, and a posterior transverse narrowing of the nasals and frontals at the vertex. Our phylogenetic analysis reveals that Mamaziphius n. gen. is nested within the crown ziphiids, as sister group of the berardiines. In addition, we introduce two new clade names within Ziphiidae, namely, Messapicetiformes (for the so-called "Messapicetus clade") and Vomeroziphii (for Ziphiinae + Hyperoodontinae and closely related forms). Another fragmentary specimen from the Pisco Formation is also briefly described herein. Furthermore, a comprehensive reappraisal of the geological age of the fossil beaked whales of Peru is provided based on new age calibrations, thus restricting the whole rich Peruvian record of this family (including the earliest-branching ziphiid, Ninoziphius platyrostris, which comes from Pisco-equivalent strata of the Sacaco area) to a Tortonian-Messinian interval younger than 9.10 Ma. No other inland unit worldwide preserves a record of fossil ziphiids as abundant, diverse and chronostratigraphically well-constrained as the Pisco Formation. In view of this, the absence of Vomeroziphii from the fossil content of the Pisco strata remains quite enigmatic.
... The Globigerina marls are considered Middle to Late Lutetian in age and according to ŽIVKOVIĆ & BABIĆ (2003), these deposits in Pazin (Istrian) basin has been assigned to the lower part of the planktonic foraminiferal Zone P12 of BERGGREN et al. (1995), corresponding to Zone E10 of BERGGREN & PEARSON (2005). This age aligns with nannoplankton dating performed by BENIĆ (1996), who determined the NP15 -NP16 nannoplankton zone. ...
The scenic beauty of Central Istria is characterized by a balanced blend of grey and ochre colours, harmoniously set amidst lush greenery. The region’s incised and hilly relief, ancient towns atop prominent hills, a diverse array of colours, and tranquil ambience owe their existence to its unique and dynamic geology. This field trip offers insights into the fusion of geological foundation and landform evolution, unravelling the interconnected narrative of geology and geomorphology. By studying this facet of Istria, we recognize that comprehending nature’s extraordinary connections necessitates collaboration across diverse scientific disciplines. To gain an understanding of the region’s geomorphic aspects, we delve into its geological foundation through the lenses of stratigraphy, lithology, mineralogy, and tectonics.
The main objective of this field trip is to explore Central Istria, renowned for its characteristic flysch deposits, which will be closely examined throughout the excursion, from two key perspectives. Firstly, we will investigate the stratigraphic evolution and the remarkable diversity of these flysch deposits, given their direct role in landscape formation. Secondly, we will study the ongoing geomorphological processes responsible for shaping the landscape formed by these deposits.
The field trip encompasses five stops, each carefully selected to showcase various sediment types. These stops demonstrate distinct geomorphological processes that
have contributed to shaping the unique relief visible on the surface today, ultimately defining the terrain known as “Grey Istria”.
... the base of the Quaternary Period/System and Pleistocene Epoch/Series was changed (Gibbard et al., 2010). The relevant Global Stratotype Section and Point (GSSP), formerly placed at $1.77 Ma (Berggren et al., 1995) at the base of the Calabrian Stage (Vrica, Italy), was re-assigned to the existing GSSP at the base of Gelasian Stage (Monte San Nicola, Italy) with an age of 2.588 Ma (Gibbard and Head, 2009;Gibbard et al., 2010). Those changes were ratified by the International Union of Geological Sciences in 2009 (Gibbard et al., 2010). ...
... Definition: The topmost of this zone is marked by the Lowest Occurrence (LO) of Trilobatus trilobus Stratigraphic position and thickness: This zone is found at the base of Nukhul Formation of (ARS-6 Well, depth 2865 m. with a thickness of 6 m.) and it is found in this depth only and not found at the SIDRI-20 well. Equivalents: This zone is equal to the Globiginantella insueta-Catapsydrax dissimilis Zone of (Berggren et al. 1995) ...
Lower Miocene Nukhul Formation of two onshore wells (ARS-6 and SIDRI-20) situated in the Eastern side Gulf of Suez was investigated for their planktonic foraminiferal content to define its geologic age. The identified planktonic foraminifera contain 20 species belonging to 9 genera. The allocation of the planktonic foraminifera proposes two planktonic biozone of ARS-6 well. The Nukhul Formation is the oldest syn-rift deposits in the Gulf of Suez rift system in Egypt and it is an important exploration target and oil-producing reservoir in the Gulf of Suez. It is the primary hydrocarbon producer for fifteen fields in the region. However, local tectonics affect the reservoir quality and determining the exact age of the Syn-rift Nukhul Formation. This research aims to determine the age of the first Syn-rift rock unit in the Abu Rudeis-Sidri field using planktonic foraminifera. The age of Nukhul Formation is a controverse and previous work on them show the differences in their ages. The biostratigraphic analyses indicate that the Nukhul Formation reveals Burdigalian age.
... The Cergowa Beds were deposited in the synorogenic Dukla Basin, a part of the Central Carpathian Basin during the Lower Oligocene (Ślączka, 1971;Starek et al., 2013;Pszonka, 2015;Pszonka et al., 2019). Directional sedimentary structures indicate prevailing palaeotransport towards the SE Fig. 2. Lithostratigraphy of the Dukla and Silesian Tectonic Units (after Ś lączka and Kamiński, 1998); supplemented with a time scale (after Berggren et al., 1995;Gradstein and Ogg, 1996) and sea level oscillation after Haq et al. (1987). The red dot shows the Cergowa Beds lithosome within a fine-grained formation of the Menilite Beds. ...
Mineral liberation analysis (MLA) is a computer-automated technique used to identify and quantify minerals
with scanning electron microscopy (SEM) based on backscattered electron (BSE) imaging, energy dispersive X-
ray spectra (EDX), and dedicated software platform that automates data processing. The MLA technique was
applied to the Cergowa Beds sandstones (Lower Oligocene of the Outer Carpathians), in which two lithofacies
were recognised: clean and muddy sandstones. The sandstones were classified as calclithites by point-counting in
transmitted light, supported by X-ray diffraction. The applied grain-based X-ray mapping (GXMAP) mode of the
MLA detailed the petrographic analysis, detecting inhomogeneous sandstone components that are too complex to
be captured using other techniques because of component size or disordered mineral structures. Moreover, the
applied automated system provides high-resolution measurements, with representative statistics produced
without subjective and tedious manual work. Here, the mineral liberation analysis system is applied to provide a
distribution of intergranular spaces that constitute slightly altered primary porosity. However, objects with
similar grey scale values in the backscattered electron (BSE) images cannot be separated, therefore the presented
distribution of intergranular spaces may be affected by other constituents of the same mineral composition, here
by the calcite replacement of grains. Their separation was performed in MATLAB based on area and four
dimensionless shape factors (circularity, Feret ratio, ellipse factor and fractal dimension) that were determined
based on the size and shape characteristics of sandstone components, observed in the transmitted light. The
distribution of primary pores, contingent on grain size and shape, can facilitate the recognition of facies and
related sedimentary processes. This is shown on the example of a hybrid bed containing clean sandstone,
deposited incrementally by high-density turbidity currents, and succeeded by muddy sandstone, deposited by a
more cohesive flow. The primary porosity distribution in specific depositional facies gives a possibility to predict
lateral changes in parts of rock bodies where geological data are lacking, and some of which may represent
excellent reservoirs.
... The Early Eocene ash in the Greifswalder Oie cementstones has a basaltic composition and is identical to the 'positive' series (positively numbered) ashes of the diatomic Danish Fur Formation (mo-clay) (Pedersen and Surlyk 1983; Larsen . These Danish ash layers were biostratigraphically classified by Berggren et al. (1995) to 54.5-54.0 Ma, which agrees well with the results from Ar-Ar isotopic dating (54.04 ± 0.14 Ma; Chambers et al. 2003). ...
Biophotonic nanostructures rarely withstand fossilization processes occurring after burial over geologic time. Even more distinctive is a change introduced to the optical properties during diagenetic processes resulting in a different optical appearance. Here, we report and explain the optical appearance of centric diatom frustules obtained from ash-bearing carbonate-cemented concretions on the Greifswalder Oie island (Pomeranian Bay, Germany, southern Baltic Sea). The ultrastructural and mineralogical analysis of the fossil frustules were carried out using electron microscopy techniques and were correlated to the macroscopic and microscopic optical appearance of the frustules before and after acid etching. The unique optical properties of the fossil diatoms were associated with diagenetic nanocrystalline calcite filling the frustules' areolae. This fill created the macroscopic pale-yellow colour of many frustules, a microscopic iridescence probably associated with diffraction grating behaviour, and microscopic colour rings. The results highlight the unique permineralization process of diatom frustules and might be an addition to the emerging studies on frustule optics and photonics.
... We have corroborated their stratigraphic occurrences by using the Shallow Benthic Zones (SBZs) of Serra-Kiel et al. (1998) and a detailed micropaleontological study of the standard calcareous nannofossil biozones for correlation with the global chronostratigraphic scale (Geological Time Scale, Gradstein et al., 2020). References for Paleogene calcareous nannofossils include Martini (1971;NP biozones), Okada and Bukry (1980; CP biozones), Varol (1989;NNT zones), and Agnini et al. (2014; CNP/CNE/CNO biozones) that integrate biozones with the geomagnetic polarity chrons (Berggren et al., 1995;Serra-Kiel et al., 1998;Berggren and Pearson, 2005). SBZs are built by Oppelian zones that integrate parallel scales of different systematic groups (Alveolina, Nummulites, orthophragminids and soritids, among others) and correlations with the global standards, although recalibrations might be still necessary for some intervals (Serra-Kiel et al., 2016;Pignatti and Papazzoni, 2017;Silva-Casal et al., 2021;Rodriguez-Pint o et al., 2022;Benedetti et al., 2023). ...
Precise taxonomy and the chronostratigraphic calibration of the Middle Eocene Alveolina from Central Iran is here undertaken from the Chah-Talkh section of the southern Sabzevar region (Central Iran). We have identified Alveolina kieli, Alveolina stercusmuris and Alveolina nuttalli along with the new species Alveolina ozcani n. sp. that we include into the Alveolina elliptica group. We have also found Nummulites uroniensis,Nummulites obesus and Nummulites cf. verneuili and associated calcareous nannofossils that look reliable to make thoughtful correlations with the Shallow Benthic Zones (SBZ). The foraminiferal biostratigraphy suggests an assignment to the upper part of the lower Lutetian–lower part of the middle Lutetian, SBZ13 (Middle Eocene), further strengthened through the identification of the calcareous nannofossil NP14b–NP15b or CNE8–CNE10
biozones, providing a solid correlation with the global stratigraphic standards.
... The interval from 3.15 to 2.85 Ma was long enough to be reliably identified and correlated between marine sequences from different ocean basins, independent of climatic characteristics, owing to its proximity to a number of biostratigraphic and magnetostratigraphic events (Berggren et al. 1985;Dowsett 1989). Dowsett et al. (1999) redefined the PRISM interval for PRISM2, as a period of warm and relatively stable climate (compared to high amplitude glacial -interglacial cycles in the Late Pleistocene) lying between the transition of marine isotope stage (MIS) M2 and M1 and MIS G19 and G18 (Shackleton et al. 1995) in the middle part of the Gauss Normal Polarity Chron, which was equivalent to 3.29 to 2.97 Ma using the updated geomagnetic polarity time scale of Berggren et al. (1995) (text- fig. 1). ...
Global reconstructions of Pliocene climate provide important insights into how the climate system operates under elevated temperatures and atmospheric CO2 levels. These reconstructions have been used extensively in paleoclimate modeling experiments for comparison to simulated conditions, and as boundary conditions. Most previous work focused on the Late Pliocene interval known as the mid Piacenzian Warm Period (mPWP), the interval originally identified by the U.S. Geological Survey Pliocene Research, Interpretation and Synoptic Mapping Project (PRISM) as the PRISM interval or Mid Pliocene Warm Period. The term Mid Pliocene Warm Period is a misnomer due to changes to the geological time scale, and its use should be discontinued. The Pliocene Model Intercomparison Project (PlioMIP), now in its third phase, is expanding to include a focus on the Early Pliocene (Zanclean). PlioMIP3 experiments will allow comparison of environmental and climatic conditions before and after closure of the Central American Seaway (CAS). PlioMIP3 used the annual insolation pattern at the top of the atmosphere to determine time slices in the Zanclean that have orbital configurations that are most similar to modern. Two have been selected by PlioMIP and adopted by PRISM for inclusion in future studies: PRISM5.1 (4.474 Ma) and PRISM5.2 (4.870 Ma). Here we establish the stratigraphic framework for these Early Pliocene time slices and furnish information to help locate these intervals in proxy records of paleoenvironmental data using oxygen isotope stratigraphy, paleomagnetic stratigraphy, biostratigraphy, and biochronology (calibrated planktic foraminifer and calcareous nannofossil events).
... Conversely, the Top of I. recurvus is well recognized at Site 1209 and Hole U1411B, with an age of 32.19 and 32.14, respectively. However, its extinction is commonly considered "one of the most inconsistent datums" (Berggren et al., 1995). • The Base of S. akropodus documented at Site 1209 and Hole U1411B (age estimate of 33.19 Ma and 33.38 Ma, respectively) is consistent with records from the South Atlantic (Site 1263; Bordiga et al., 2015), being found in the upper part of Zone CNO1. ...
... The current Shallow Benthic zonation was originally compiled by Serra-Kiel et al. (1998) for the Danian to Priabonian and by Cahuzac and Poignant (1997) for the Rupelian to Tortonian. The "SBZ" zones are Oppelian in nature, with fuzzy boundaries, and were originally correlated to the timescale of Berggren et al. (1995) using magnetostratigraphy and standard planktonic microfossil zonations (Pignatti and Papazzoni 2017). In the terminology of the latest version of the Stratigraphic Code, the original SBZ consists of "assemblage zones" (North American Commission on Stratigraphic Nomenclature 2021). ...
... Furthermore, evolution and modifications in the test morphology of planktonic foraminifera are highly susceptible and responsive to shifting environmental conditions, with observed morphological variations often triggered by the everchanging environment (Hecht and Savin, 1972;Renaud and Schmidt, 2003;Schmidt et al., 2004). This leads to high observed taxonomic turnover and rapid evolution rates in planktonic foraminifera, subsequently providing exceptional analytical utility, with researchers favoring their use as a dominant index fossil in Mesozoic and Cenozoic marine biostratigraphy (Berggren et al., 1995;Wade et al., 2011;Fraass et al., 2015). Based on these assets and advantages, the study of planktonic foraminifera has shown promise in biostratigraphy, in clarifying the environmental changes, and for understanding the evolutionary importance of the species. ...
... The evolution and extinction events of fossil species are extensively used by biostratigraphers to date and correlate marine sediments (e.g. Berggren et al., 1995;Wade et al., 2011;King et al., 2020;Raffi et al., 2020), and the tests are frequently used in palaeoceanography because they hold information about past oceanic environments. Systematic taxonomy within the group relies almost exclusively on shell morphology. ...
We describe Globigerinoides rublobatus n. sp., a new morphospecies of fossil planktonic foraminifera, from the Pleistocene sediments (∼810 ka) of the Indian Ocean and Pacific Ocean. We use image analysis and morphometry of 860 specimens from International Ocean Discovery Program Site U1483 in the tropical Indian Ocean to document morphological variability in the new morphospecies and related taxa, and we also report it from Pacific Ocean Site U1486 for the first time. The new morphospecies combines characteristics typical of Globigerinoides conglobatus (Brady, 1879) and Globigerinoides ruber (d'Orbigny, 1839), with which it co-occurs, but is distinct from both. Morphometric data indicate that G. rublobatus n. sp. is closer to G. conglobatus, potentially signalling an evolutionary affinity. We find that Globigerinoides rublobatus n. sp. occurs as two variants, a pigmented (pink) form and a non-pigmented (white) form. The non-pigmented forms are on average ∼50 % larger than the pigmented forms. This is so far only the third instance of fossil planktonic foraminifera known to exhibit this pink pigmentation. We regard the pink and white forms as variants of a single morphospecies and suggest the pink form may represent a later evolutionary adaptation.
... Biostratigraphically, the oldest record of such elements is found in the Zone N. 13 of Blow (1969) (Masuda and Noda, 1977 ;Ogasawara and Sato, 1986;Oishi et al., 1993), and the youngest record in Zone N. 17 (Fujiwara, 1992 ;Saito and Isawa, 1995). According to the latest time scale of Berggren et al. (1995), the base of N. 13 is estimated to be 12.1 Ma, and the upper limit of N. 17 to be 5.6 Ma. Consequently, the molluscan assemblage including such elements persisted for the duration of 6.5 m. y. during a late Middle-early Late Miocene interval. ...
... The presence of Neogloboquadrina acostaensis, Globoturborotalita nepenthes, Globorotalia margaritae, and Gr. crassaformis in this area suggests a planktonic foraminifera zonal range spanning from N16 to N20-21 (Berggren et al., 1995), partially aligning with the calcareous nannoplankton zones NN11 and NN12 (Fig. 7). Previous studies have used the presence of Gr. margaritae and Gr. ...
This study describes the sedimentary facies associations of the incised valley fill deposits, which allowed the reconstruction of the Late Serravallian–Early Tortonian palaeogeographic evolution of the Adana Basin, one of the largest peri-Mediterranean basins in southern Türkiye. The incised valley fill disconformably overlies the offshore mudstones and comprises fluvial and tide-dominated estuarine facies associations from base to top. The fluvial deposits comprise intercalated channel fill and overbank deposits. The laterally accreted point bars of the meandering river channel deposits consist of conglomerates and sandstones, while the overbank deposits form sheet-like beds of sandstones, siltstones and mudstones. These are overlain by fine- to coarse-grained marine sandstones rich in oyster fossils at the boundary. The sandstones show planar and trough cross-stratification, sigmoidal beds and herringbone cross-stratifications bounded by reactivation surfaces. These bi-directional sand bars, up to 150 cm in height, indicate tidal-bar deposits of the estuarine facies association. The biostratigraphic dating of the incised valley fill deposits suggests an age of approximately 11.78–11.19 million years, indicating the MMi8-MMi9 zone, based on planktonic foraminifera from underlying and overlying marine sediments. The deposits developed in response to the Late Serravallian relative sea-level fall that partially exposed the Adana Basin, indicating a regional forced regression and unconformity. The sediment supply led to the deposition of the thick fluvial deposits at the base of the incised valley due to the low relative sea-level rise rate. Progressive sea-level rise drowned the incised valley, transforming it into a marine embayment where tidal bars were deposited in a tide-dominated estuarine environment. This study shows that even in a microtidal setting like the Neogene Mediterranean, a tide-dominated estuarine environment can develop in response to the confinement and consequent amplification of the tidal currents in a funnel-shaped, narrow and shallow incised valley.
The Eocene–Oligocene transition (EOT, ca. 40–
33 Ma) marks a transformation from a largely ice-free to an
icehouse climate mode that is well recorded by oxygen-stable
isotopes and sea surface temperature proxies. Opening of the
Southern Ocean gateways and decline in atmospheric car-
bon dioxide levels have been considered as factors in this
global environmental transformation and the growth of ice
sheets in Antarctica during the Cenozoic. A more compre-
hensive understanding is still needed of the interplay be-
tween forcing versus response, the correlation among envi-
ronmental changes, and the involved feedback mechanisms.
In this study, we investigate the spatio-temporal variation in
export productivity using biogenic Ba (bio-Ba) from Ocean
Drilling Program (ODP) sites in the Southern Ocean, focus-
ing on possible mechanisms that controlled them as well as
the correlation of export productivity changes to changes in
the global carbon cycle. We document two high export pro-
ductivity events in the Southern Ocean during the late Eocene
(ca. 37 and 33.5 Ma) that correlate to proposed gateway-
driven changes in regional circulation and to changes in
global atmospheric pCO 2 levels. Our findings suggest that
paleoceanographic changes following Southern Ocean gate-
way openings, along with more variable increases in circu-
lation driven by episodic Antarctic ice sheet expansion, en-
hanced export production in the Southern Ocean from the
late Eocene through early Oligocene. These factors may have
played a role in episodic atmospheric carbon dioxide reduc-
tion, contributing to Antarctic glaciation during the Eocene–
Oligocene transition.
The Eocene Kuldana Formation (KF) in the Yadgar area of Pakistan, comprises a diverse range of sedimentary facies, including variegated red beds of shales, mudstones, and sandstones, as well as interbedded limestone and marl. In this study, we conducted an integrated micropaleontologi-cal, sedimentological, mineralogical, and geochemical investigation to determine the depositional setting , biochronology, provenance, and paleoclimate of the KF. The study identified six lithofacies and six microfacies, which indicate a variety of environments ranging from floodplains and channels to the margins and shallow marine settings. The nannofossil biostratigraphy places the KF in the Early Eo-cene, more precisely the NP10 zone (Ypresian), and the fossil zone of benthic foraminifera classifies the study section as the Shallow Benthic Zone SBZ-8 (Middle Ilerdian 2). In terms of petrography, the KF sandstone was classified as litharenite and feldspathic litharenite, while the QtFL diagram suggests a recycled orogen. Geochemical proxies indicate an oxidizing environment, a high-to-low regular sedi-mentation rate, moderate-to-intense chemical weathering in the source region, and a warm-humid to dry climate during the deposition of KF. Overall, the findings suggest that the deposition of KF marks the end of Neo-Tethys due to the Early Eocene Indian-Kohistan collision and that the uplifting of the Himalayas provided the source for the deposition of KF in the foreland basin. The study provides new insights into the depositional environment, biochronology, provenance, and paleoclimate of KF, and highlights the potential for red beds as reliable indicators of oxygenation levels in proximity to mineral deposits.
Planktonic foraminiferal zones PL4 and PL5 were correlated to the siltstone facies of the Shimajiri Group distributed in Miyagi-jima and adjacent islands, east of Okinawa-jima. The base of the Chinen Formation has yielded Pleistocene CN13b calcareous nannofossils and N22 planktonic foraminiferal zones.
The Yonabaru and Shinzato formations in southern Okinawa-jima are demarcated by a distinct tuff bed near the base of Zone PL5 defined by the last occurrence of Dentoglobigerina altispira. However, this boundary key bed is absent in Miyagi-jima and adjacent islands, likely due to limited channel-fill sediment distribution. Neogene deposits of Okinawa-jima and Miyagi-jima have incorrectly been correlated with each other in previous studies, and should be merged into the Shimajiri Formation as their lithofacies are indistinguishable.
An analysis of planktonic foraminiferal assemblages suggests seawater cooling after the mid-Pliocene warm period or intensification of upwelling due to the enhanced Asian monsoon during PL5.
Marginal and deeper marine facies typify the Miocene exposures along the western margin of the Gulf of Suez rift basin. The stratigraphic setting of these facies is a subject of debate and confusing at best. Integrative sedimentological and sequence stratigraphic study of successions exposed in the St. Paul and El‐Zeit blocks provides insight into the lateral relationships between the two facies and their evolution, a topic that is not fully understood. The St. Paul block, located at the basin margin, has thin shallow marine facies, while the succession of El‐Zeit block, situated near the basin axis, consists of basal conglomerates, thin shallow marine carbonates, thick deeper marine shale and marginal evaporites. The facies architecture of these successions is interpreted as belonging to two different depositional models: a fan‐delta/lagoon system followed upwards by an alluvial fans/sabkha‐tidal flat system in the St. Paul hangingwall basin, and carbonate–siliciclastic–evaporite systems on the hangingwall dip‐slope ramp of El‐Zeit block. These models may help understanding the sedimentary history of other similar blocks in the rift basin. The studied facies show many striking features such as deposition during tilting of fault block, abrupt facies and thickness variations, coarse clastic shedding, erosion channel filling, onlapping of high standing blocks and evaporite accumulation. These features are the result of major tectonic events that triggered the formation of unconformities at different hierarchical levels during the late early to middle Miocene. These unconformities subdivide the Miocene facies into five depositional sequences separated by basin‐wide erosional boundaries. This division greatly improves the age control of marginal marine facies. It affords new insight into the evolution of marginal marine facies along the western margin of the basin in relation to deeper facies in the basin centre. Facies and thickness changes in these tectonically induced sequences indicate that basin floor irregularities, subsidence rates, climatic changes, variable sediment influx, sea‐level/brine‐level changes and basin isolation/connection to the Mediterranean Sea are also important factors responsible for their evolution.
The sedimentary succession penetrated by the Well Z, OPL 310 Dahomey basin, South western Nigeria has been investigated for their microfaunal content. A total of fifty ditch cutting samples from the well were processed and analysed for foraminifera following the standard procedures. The result of the analysis revealed moderately rich and diverse macrofauna totalling a hundred and seven (107) species out of which sixty-five (65) are benthonic and forty-two (42) are planktonic foraminifera species. The sedimentological analysis of the samples revealed two (2) sedimentary sequences: a basal sandstone unit characteristically milky white, coarse to pebbly, sub-angular and poorly sorted with alternation of marine shale overlain by a dark grey, non-fissile shale wih glauconite pellets and mica flakes alternating with sandstone which shows that sediments belong to Oshosun and Afowo Formation respectively. Based on First Downhole Occurrences (FDO) and Last Downhole Occurrences (LDO) of the foraminiferal index forms, four planktonic foraminiferal zones and One benthonic zone corresponding to the P14, P18-P21, N9-N14, N16 and N17 of Blow (1969, 1979) were proposed for the well. The planktonic zones are Globorotalia opima opima Interval zone, Orbulina universa-Globorotalia mayeri Concurrent-range Zone, Globorotalia acostaensis Interval range Zone, Globorotalia plesiotumida Taxon range Zone and the benthonic foraminiferal zone proposed is Uvigerina hourqi Taxon range zone. These zones were used to delineate the sedimentary succession from Middle Eocene to Late Miocene age.
Pulleniatina is an extant genus of planktonic foraminifera that evolved in the late Miocene. The bottom and top occurrences of its six constituent morphospecies (P. primalis, P. praespectablis, P. spectabilis, P. praecursor, P. obliquiloculata, P. finalis) provide a series of more or less useful constraints for correlating tropical and subtropical deep-sea deposits, as do some prominent changes in its dominant coiling direction and a substantial gap in its record in the Atlantic Ocean. Biostratigraphic information about these events has accumulated over many decades since the development of systematic deep-sea drilling in the 1960s, during which time the geochronological framework has evolved substantially, as have taxonomic concepts. Here we present new data on the biochronology of Pulleniatina from International Ocean Discovery Program Site U1488, which has a record of its entire evolutionary history from the centre of its geographic range in the Western Pacific Warm Pool. We then present and compare revised calibrations of 183 published Pulleniatina bioevents worldwide, with stated sampling errors as far as they are known, using a consistent methodology and in the context of an updated evolutionary model for the genus. We comment on the reliability of the various bioevents; their likely level of diachrony; and the processes of evolution, dispersal, and extinction that produced them.
The Magadi-Natron Basin, which formed at ~7 Ma, lies in a tectonic sump in the southern Kenya Rift. The oldest lake sediments include the Plio-Pleistocene Endosapia and Leshuta formations west of Lake Magadi and the Pleistocene Hajaro Beds and Peninj Group west of Lake Natron. Volcanism developed intermittently with the Magadi Trachyte flood lavas (1.4 to 0.8 Ma) infilling pre-existing grabens. Renewed faulting created basins in which the Oloronga (~1 Ma–380 ka in cores), Green (~380–105 ka in cores; up to 40 ka in outcrop?) and Orkaramation Beds (post-Oloronga) accumulated. The Oloronga Beds include silty sand, diatomaceous and zeolitic silt and mud and chert. Tufa chimneys are locally common in outcrops. Pollen and diatoms are well preserved in cores. The Orkaramation Beds, up to 10 m thick, consist of diatomaceous silts and sands with gastropods and fish fossils. The Green Beds are confined to the modern axial rift and include green and orange tuffaceous mud, silt, siltstone, abundant chert, and evaporites with indicators of dilute and saline alkaline waters. Four major environmental phases are recognised. Phase I (1000–740 ka) was characterised by fresh to mildly saline lakes. Palaeolakes reached maximum extent and depths during Phase II (~740–500 ka) with conditions becoming drier through to 325 ka (Phase III). Phase IV was characterised by a saline palaeolake but with fluctuating wet-dry climates. Palaeolake salinity tended to increase through the last million years.
Sedimentological and biochronological analyses were undertaken on carbonate deposits from 20 seamounts belonging to the Marcus–Wake Seamount Group, the Magellan Seamounts, and the Marshall Islands Seamounts in the JA area, northwestern Pacific Ocean. Deposition of carbonates on the JA seamounts varied markedly with age. The oldest carbonate deposits are Lower to middle Cretaceous shallow‐water limestones containing mollusks (including rudists), scleractinian corals, and calcareous sponges. Upper Cretaceous and Paleocene carbonates are rare, and no Oligocene carbonates may exist. In contrast, Eocene foraminiferal packstones are widespread, and Miocene–Pleistocene foraminiferal ooze covers the JA seamounts. The limited occurrence of Paleogene carbonate deposits on the JA seamounts is consistent with global observations (i.e., a paucity of Paleogene carbonates). The Cretaceous–Eocene carbonates have been phosphatized, whereas Miocene and later limestones have not. This fact, along with the results of previous studies, suggests that carbonate rocks on seamounts were phosphatized globally during the Oligocene. Upwelling of nutrient‐rich bottom waters during this time is likely responsible for the limited occurrence of Oligocene carbonate rocks on the JA seamounts. The thicknesses of the pelagic caps, which consist mainly of Miocene and younger foraminiferal oozes, varies among the seamounts and depends at least partly on the topography of the top of the seamount.
Amongst the various Neogene sequences in India, Andaman-Nicobar Basin in the northern Indian Ocean is one of the most important basins in this part of the world that represents the marine deep-water facies with a few shallow-water sequences. The Neogene sediments of the basin archives abundant siliceous microfossils namely radiolarians, diatoms, silicoflagellates as well as planktic and benthic foraminifers, calcareous nannofossils, calcareous algae etc. The Neogene marine sediments exposed on different islands in the Andaman and Nicobar Group in the northern Indian Ocean endows an excellent opportunity to establish a comprehensive biostratigraphy and to reconstruct paleoenvironment as well as overall paleoceanography based on qualitative and quantitative analyses of the marine biogenic components that can be used as proxies for paleotemperature, nutrient availability and other environmental parameters. For the reconstruction of past oceanographic changes, retrieval of proxy biotic records from the marine realms is a unique tool. The calcareous nannofossils and siliceous microfossils from the outcrops on the Andaman and Nicobar Group of islands and the same recorded from the offshore sediments show a diverse assemblage of tropical low latitude marker/index forms. Based on the recovered assemblages and marker taxa the age has been calibrated from late early Miocene to Plio-Pleistocene boundary. Some significant events e.g., Miocene Climate Optimum (MCO), upwelling and intensification of Indian Summer Monsoon (ISM), low biogenic silica and cooling etc. in different geological time slices have been recognized from the recovered assemblages of siliceous microfossils and calcareous nannofossils as well as evidence from other microfossils. The depositional environment, bathymetry and rate of sedimentation also have been estimated from the marker/index taxa.
The Mg/Ca of marine calcareous Planktic Foraminifera (PF) shells is commonly used for sea surface temperature reconstructions. However, compared to open marine environments, hypersaline (>40) oligotrophic seas have been shown to accommodate PF with higher Mg/Ca and divergent temperature to Mg/Ca relationships. To investigate influencing factors of PF Mg uptake in hypersaline regions, we measured the Mg/Ca of two flux‐dominating PF species, Globigerinoides ruber albus and Turborotalita clarkei, derived from a monthly resolved time series of sediment traps in the Gulf of Aqaba, northern Red Sea as well as the corresponding temperature, salinity, and pH values. The PF exhibit elevated Mg/Ca which cannot be explained by post‐deposition or interstitial sediment diagenetic processes. G. ruber albus displays Mg/Ca trends that strongly follow seasonal mixed layer temperature changes. Conversely, T. clarkei Mg/Ca trends do not follow temperature but rather show significant Mg/Ca enrichment following mixing of the surface water column. We present a framework for incorporating elevated Mg/Ca into global Mg/Ca‐T calibrations for G. ruber albus and present a new Mg/Ca‐T calibration suitable for hypersaline marine environments.
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