scholarly journals On the age and correlation of the St. Erth Beds, S.W. England, based on planktonic foraminifera

1986 ◽  
Vol 5 (2) ◽  
pp. 93-105 ◽  
Author(s):  
D. Graham Jenkins ◽  
John E. Whittaker ◽  
R. Carlton
Keyword(s):  
Planktonic Foraminifera ◽  
Late Pliocene ◽  
Stratigraphic Ranges

Abstract. The paper illustrates and describes 15 species of planktonic foraminifera from the St. Erth Beds, Cornwall, S.W. England. The overlap of the stratigraphic ranges of Globorotalia inflata (d’Orbigny), G. praehirsuta Blow, G. tosaensis Takayanagi & Saito, Pulleniatina primalis Banner & Blow, Neogloboquadrina humerosa (Takayanagi & Saito) and dextrally coiled N. pachyderma (Ehrenberg) places the age of the fauna in the Globorotalia inflata Zone, Late Pliocene. The absence of Globorotalia puncticulata (Deshayes), G. truncatulinoides (d’Orbigny) and Neogloboquadrina atlantica (Berggren) confirms this age assignment and with the presence of G. inflata (d’Orbigny), the deposition of St. Erth beds can now be accurately placed at between 2.1 and 1.9 Ma. For this paper, it has been acceped that the Pliocene-Pleistocene boundary is marked by the first evolutionary appearance of G. truncatulinoides at about 1.9 Ma.

Globoconella Pseudospinosa, N. Sp.: a New Early Pliocene Planktonic Foraminifera from the Southwest Pacific

2018 ◽  
Vol 48 (4) ◽  
pp. 288-300 ◽  
Author(s):  
Martin P. Crundwell
Keyword(s):  
New Zealand ◽  
Late Miocene ◽  
East Coast ◽  
Planktonic Foraminifera ◽  
Ocean Drilling Program ◽  
Late Pliocene ◽  
Early Pliocene ◽  
Southwest Pacific ◽  
Project Site ◽  
Stratigraphic Ranges

Abstract Studies of topotypes of Truncorotalia crassaconica from the East Coast Basin of New Zealand and populations of Tr. crassaconica at Ocean Drilling Program Site 1123 and Deep Sea Drilling Project Site 284 in the southwest Pacific revealed two morphospecies. One of these is a late Pliocene species, Truncorotalia crassaconica s.s., that has low, slit-like apertures with thin, smooth apertural lips. The other is Globoconella pseudospinosa n. sp., an early Pliocene form with arched apertures and pustulose apertural lips. The short stratigraphic ranges of both species are potentially useful as biostratigraphic markers for the subdivision of Plio-Pleistocene stages in New Zealand and the temperate southwest Pacific. Populations of Gc. pseudospinosa, with mostly sinistrally coiled specimens, occur throughout the lectostratotype of the New Zealand Opoitian Stage at Mangapoike River in the East Coast Basin and are confined to the early Pliocene (Opoitian) at sites 1123 and 284, between 4.57 and 4.10 Ma. Small populations of Tr. crassaconica s.s., with mostly dextrally coiled specimens, occur in the late Pliocene (Waipipian Stage) between 3.53 and 2.98 Ma. Sporadic occurrences of relatively rare, mostly sinistrally coiled specimens of Tr. aff. crassaconica occur earlier at sites 1123 and 284 in the late Miocene to Pliocene between ca. 5.5 and 3.53 Ma. These specimens are distinguished in having open umbilici and almost straight umbilical sutures, similar to the late Miocene specimens of Truncorotalia crassaformis.

Campanian-Maastrichtian ammonite and planktonic foraminiferal biostratigraphy from Tercis, France: Implications for defining the stage boundary

1997 ◽  
Vol 71 (3) ◽  
pp. 407-418 ◽  
Author(s):  
Peter Ward ◽  
William Orr
Keyword(s):  
Planktonic Foraminifera ◽  
New Information ◽  
Biogeographic Provinces ◽  
Lower Maastrichtian ◽  
Stratotype Section ◽  
Stratigraphic Ranges ◽  
Excellent Source ◽  
Source Of Information ◽  
Reference Section ◽  
Upper Campanian

The Campanian-Maastrichtian-aged Grande Carriere quarry near Tercis, southwest France, contains a diverse and abundant assemblage of both micro-and macrofossils from a thick sequence of well-exposed limestones. Its fauna is also a mixture of both Boreal and Tethyan Province species. Because of these two traits, the quarry provides an excellent source of information about integrated biostratigraphic events among diverse taxa, as well as providing a reference section for correlation between the two biogeographic provinces. The quarry has recently been proposed as a candidate for the Campanian/Maastrichtian boundary stratotype section, while one ammonite found there, Pachydiscus neubergicus, has been proposed as the index fossil marking the base of the Maastrichtian Stage. We have made collections of Upper Cretaceous ammonites and planktonic foraminifera from limestones exposed in, and near this site, which yield new information about the relative stratigraphic ranges of Upper Campanian and Lower Maastrichtian ammonites and foraminifera.

scholarly journals Eastern Mediterranean foraminiferal palaeoecological response to Mid-Late Pliocene climatic regime: A preliminary note.

2016 ◽  
Vol 47 (1) ◽  
pp. 112 ◽  
Author(s):  
H. Drinia ◽  
A. Antonarakou ◽  
S. Mihalakopoulos ◽  
E. Tsiolakis
Keyword(s):  
Marine Sediments ◽  
Sedimentation Rate ◽  
Eastern Mediterranean ◽  
Planktonic Foraminifera ◽  
Preliminary Note ◽  
Climatic Influence ◽  
Late Pliocene ◽  
Orbital Perturbations ◽  
Southern Cyprus ◽  
Climatic Regime

The main objective of this work is to investigate the climatic influence on the sedimentation during mid to late Pliocene in Cyprus island. For this reason, a section located in Pissouri sub-basin, southern Cyprus, was chosen to be studied. The section comprises a nearly uninterrupted succession of marine sediments, dominated by grey marls, which are cyclically alternating with yellowish silty marls. The identification of age diagnostic planktonic foraminifera suggests a mid to upper Pliocene age. The calculated faunal parameters document cyclic fluctuations consistent with shifts in such climate belts. A good age resolution of the cycles and an indication of sedimentation rate would be required in order to connect cyclicity to orbital perturbations.

Growth of an Intermittent Ice Sheet in Iceland during the Late Pliocene and Early Pleistocene

1994 ◽  
Vol 42 (2) ◽  
pp. 115-130 ◽  
Author(s):  
Áslaug Geirsdóttir ◽  
Jón Eiríksson
Keyword(s):  
North Atlantic ◽  
Deep Sea ◽  
Planktonic Foraminifera ◽  
Ice Sheet ◽  
Ice Cover ◽  
Early Pleistocene ◽  
Oceanic Circulation ◽  
Late Pliocene ◽  
The North ◽  
Quaternary Climate

AbstractDeep-sea paleoclimatic records show that the Quaternary climate around Iceland was, and probably still is, very sensitive to rapid shifts in North Atlantic oceanic circulation. Studies of several key sections in Iceland indicate that similar oscillations are reflected in the late Pliocene and early Pleistocene terrestrial stratigraphy. Correlations between six rock sequences in western, northern, eastern, and southern Iceland show a fairly distinct trend during the Pliocene-Pleistocene transition indicating the progressive growth of an ice sheet from southeast toward the north and west. The correlations are based on K/Ar dates and paleomagnetic studies. A total of 11 glacial horizons are recorded in a stratigraphic column from eastern Iceland extending back 6.5 myr. In western Iceland, 7 glacial horizons are preserved in a rock section dated from 7.0 to 1.8 myr, and in northern Iceland 14 glacial horizons are identified in a section that extends back to 9.0 myr. Well over 20 glacial horizons have been identified in the stratigraphic column in Iceland. Full-scale glacial-interglacial cyclicity with regional ice cover is indicated at approximately 2.6 myr. A further amplification leading to islandwide glaciations is identified at 2.2-2.1 myr. These results show that changes in the ice cover in Iceland correlate with the deep-sea oxygen isotope records from benthic and planktonic foraminifera as well as IRD studies from the North Atlantic.

The age and palaeoecology of the St Erth Beds, southern England, based on planktonic foraminifera

1982 ◽  
Vol 119 (2) ◽  
pp. 201-205 ◽  
Author(s):  
D. Graham Jenkins
Keyword(s):  
Planktonic Foraminifera ◽  
Photic Zone ◽  
Late Pliocene ◽  
Southern England ◽  
Neogloboquadrina Pachyderma ◽  
First Time

SummaryPlanktonic foraminifera are recorded for the first time from the St Erth Beds but they are small and very rare. A late Pliocene G. inflaia Zone age is postulated on the presence of Globorotalia inflata and dextrally coiled Neogloboquadrina pachyderma. It is suggested that the depth of water at the time of deposition was much less than 100 m, possibly in the photic zone, and the palaeotemperature was in the range of 10–18 °C.

scholarly journals Assessing the Accuracy of Fossil Datum Levels: <i>Globorotalia margaritae</i> Foraminiferida, a Pliocene Test Case

1991 ◽  
Vol 9 (2) ◽  
pp. 225-231 ◽  
Author(s):  
P. P. E. Weaver ◽  
H. Bergsten
Keyword(s):  
Planktonic Foraminifera ◽  
Geographical Range ◽  
Test Case ◽  
Simple Explanation ◽  
Piston Core ◽  
Global Arrays ◽  
Foraminiferal Species ◽  
Stratigraphic Ranges

Abstract. The stratigraphic distribution of the planktonic foraminiferal species Globorotalia margaritae has been determined in 34 DSDP, ODP and piston core sites from throughout the world’s oceans and from one land section. All these sites have good palaeomagnetic records, and thus the age of the first and last appearance of G. margaritae can be determined in each case. The results show strong diachronism and indicate that this is not a good species to use for correlation. There appears to be no simple explanation for this diachronism, dissolution is probably a contributing factor in the deeper sites, and the edges of the geographical range of the species show shorter stratigraphic ranges but these factors do not explain all the data. We suggest that diachronism in planktonic foraminifera may be common, but without global arrays of palaeomagnetically dated cores it will be very difficult to distinguish reliable species from unreliable ones.

scholarly journals Upper Eocene planktonic foraminifera from northern Saudi Arabia: implications for stratigraphic ranges

2021 ◽  
Vol 40 (2) ◽  
pp. 145-161
Author(s):  
Bridget S. Wade ◽  
Mohammed H. Aljahdali ◽  
Yahya A. Mufrreh ◽  
Abdullah M. Memesh ◽  
Salih A. AlSoubhi ◽  
...  
Keyword(s):  
Saudi Arabia ◽  
Planktonic Foraminifera ◽  
Late Eocene ◽  
Calcareous Nannofossil ◽  
Upper Eocene ◽  
Calcareous Nannofossil Biostratigraphy ◽  
Stratigraphic Ranges ◽  
Latest Eocene ◽  
Stratigraphic Range

Abstract. The Rashrashiyah Formation of the Sirhan Basin in northern Saudi Arabia contains diverse assemblages of planktonic foraminifera. We examined the biostratigraphy, stratigraphic range and preservation of upper Eocene planktonic foraminifera. Assemblages are well-preserved and diverse, with 40 species and 11 genera. All samples are assigned to the Priabonian Globigerinatheka semiinvoluta Highest Occurrence Zone (E14), consistent with calcareous nannofossil biostratigraphy indicating Zone CNE17. Well-preserved planktonic foraminifera assemblages from the lower part of the upper Eocene are rare worldwide. Our study provides new insights into the stratigraphic ranges of many species. We find older (Zone E14) stratigraphic occurrences of several species of Globoturborotalita previously thought to have evolved in the latest Eocene (Zone E15, E16) or Oligocene; these include G. barbula, G. cancellata, G. gnaucki, G. pseudopraebulloides, and G. paracancellata. Older stratigraphic occurrences for Dentoglobigerina taci and Subbotina projecta are also found, and Globigerinatheka kugleri occurs at a younger stratigraphic level than previously proposed. Our revisions to stratigraphic ranges indicate that the late Eocene had a higher tropical–subtropical diversity of planktonic foraminifera than hitherto reported.

Late Pliocene to Early Pleistocene Planktonic Foraminifera from Northern Indian Ocean (Andaman and Nicobar Islands): Interpretation on Cooling Event and Ocean Upwelling

2021 ◽  
Vol 51 (3) ◽  
pp. 115-138
Author(s):  
Rikee Dey ◽  
Amit K. Ghosh ◽  
Ajoy Kumar Bhaumik ◽  
Arindam Chakraborty ◽  
Stuti Saxena ◽  
...  
Keyword(s):  
Indian Ocean ◽  
West Coast ◽  
Planktonic Foraminifera ◽  
Early Pleistocene ◽  
Northern Indian Ocean ◽  
Late Pliocene ◽  
Globigerina Bulloides ◽  
Neogloboquadrina Pachyderma ◽  
Nicobar Islands ◽  
Identification Analysis

ABSTRACT Thirty-two planktonic foraminiferal taxa have been identified based on Bright Field microscopic study as well as Scanning Electron Microscopy on the samples collected from the outcrop adjacent to the type section of Neill West Coast Formation at Neil Island of Ritchie's Archipelago, northern Indian Ocean. The planktonic foraminiferal taxa belong to ten genera viz., Dentoglobigerina, Globigerina, Globigerinoides, Globoconella, Globorotalia, Globorotaloides, Globoturborotalita, Neogloboquadrina, Orbulina, and Trilobatus. A number of statistical analyses have been done in addition to taxonomic study to interpret the palaeocenographic scenario. We performed PCA analysis on the foraminiferal content of the samples to test the relatedness. Two biozones have been established by Stratigraphically Constrained Cluster Analysis (CONISS). We used SHEBI (SHE analysis for biozone identification) analysis to precisely demarcate seven biozones. Attempts have been made to decipher the Plio–Pleistocene boundary in the Neill West Coast Formation based on specific zonal markers. The presence of some taxa (e.g., Globoconella inflata, Globigerina bulloides, and Neogloboquadrina pachyderma) indicates the initiation of a cooling event from late Pliocene onwards. An event of ocean upwelling also has been identified based on the presence of Globigerina bulloides, Neogloboquadrina pachyderma, and N. dutertrei from the late Pliocene to early Pleistocene of the northern Indian Ocean that also correlates with palaeoceanographic records known from other upwelling regions.

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