Bartonian-Priabonian larger benthic foraminiferal events in the western tethys

G. Less, Ercan Özcan

Research output: Contribution to journalArticle

38 Citations (Scopus)

Abstract

The composition of Western Tethyan larger benthic foraminifera (LBF) significantly changed as a consequence of the general climate cooling trend in the late Bartonian and Priabonian. Major events are characterized by the disappearance of giant forms of both Nummulites and Assilina and also of the genus Alveolina and some orthophragminid lineages. Simultaneously, radiate and especially reticulate Nummulites, the N. fabianii lineage, and nummulitids with secondary chamberlets such as Heterostegina and Spiroclypeus emerged. Based both on first/last occurrence (FO/LO) data and the evolution of these forms and integrating geological information such as field observations, other LBF and planktonic data, a high-resolution stratigraphy of the Bartonian and Priabonian could be established in the frame of the Tethyan shallow benthic zonation (with SBZ zones and newly erected subzones for SBZ 18 and 19 based on the exceptionally rapid evolution of Heterostegina). We distinguish eight Western Tethyan LBF events in this timespan, mainly based on FO/LO data of selected lineages. These are: (1) FO of the Operculina gomezi-group (SBZ 16/17), (2) FO of genus Heterostegina (SBZ 17/18a), (3) FO of the H. reticulata-lineage (SBZ 18a/b), (4) LO of giant Nummulites (with supposed eastward migration during SBZ 18b-c), (5) FO of genus Spiroclypeus (SBZ 18c/19a), (6) LO of some survivor Middle Eocene orthophragminid lineages (around SBZ 19a/b), (7) FO of Heterostegina with granules (SBZ 19b/20) and (8) LO of the majority of survivor Eocene LBF (SBZ 20/21). The most dramatic change happened between event 4, followed by the successive expansion of reticulate Nummulites, and event 5. Due to its easy recognition by field methods, the Middle/Late Eocene boundary is traditionally drawn at the base of SBZ 19 (Serra-Kiel et al., 1998), corresponding to event 5 and marked also by the intraphyletic appearance of both Nummulites fabianii and Heterostegina reticulata mossanensis. This change falls, however, within P 15 (planktic foraminifera) and NP 19-20 (nannoplankton) zones, and is therefore considerably younger than the Bartonian/Priabonian boundary placed at the boundary of NP 17/18 zones by planktonic experts.

Original languageEnglish
Pages (from-to)129-140
Number of pages12
JournalAustrian Journal of Earth Sciences
Volume105
Issue number1
Publication statusPublished - 2012

Fingerprint

benthic foraminifera
Tethys
Eocene
field method
nanoplankton
foraminifera
zonation
stratigraphy
cooling
climate

Keywords

  • Eocene
  • Extinction
  • Larger benthic foraminifera
  • Tethys

ASJC Scopus subject areas

  • Geology
  • Stratigraphy
  • Palaeontology

Cite this

Bartonian-Priabonian larger benthic foraminiferal events in the western tethys. / Less, G.; Özcan, Ercan.

In: Austrian Journal of Earth Sciences, Vol. 105, No. 1, 2012, p. 129-140.

Research output: Contribution to journalArticle

@article{57dcf2a304484acaa92efacace5cb904,
title = "Bartonian-Priabonian larger benthic foraminiferal events in the western tethys",
abstract = "The composition of Western Tethyan larger benthic foraminifera (LBF) significantly changed as a consequence of the general climate cooling trend in the late Bartonian and Priabonian. Major events are characterized by the disappearance of giant forms of both Nummulites and Assilina and also of the genus Alveolina and some orthophragminid lineages. Simultaneously, radiate and especially reticulate Nummulites, the N. fabianii lineage, and nummulitids with secondary chamberlets such as Heterostegina and Spiroclypeus emerged. Based both on first/last occurrence (FO/LO) data and the evolution of these forms and integrating geological information such as field observations, other LBF and planktonic data, a high-resolution stratigraphy of the Bartonian and Priabonian could be established in the frame of the Tethyan shallow benthic zonation (with SBZ zones and newly erected subzones for SBZ 18 and 19 based on the exceptionally rapid evolution of Heterostegina). We distinguish eight Western Tethyan LBF events in this timespan, mainly based on FO/LO data of selected lineages. These are: (1) FO of the Operculina gomezi-group (SBZ 16/17), (2) FO of genus Heterostegina (SBZ 17/18a), (3) FO of the H. reticulata-lineage (SBZ 18a/b), (4) LO of giant Nummulites (with supposed eastward migration during SBZ 18b-c), (5) FO of genus Spiroclypeus (SBZ 18c/19a), (6) LO of some survivor Middle Eocene orthophragminid lineages (around SBZ 19a/b), (7) FO of Heterostegina with granules (SBZ 19b/20) and (8) LO of the majority of survivor Eocene LBF (SBZ 20/21). The most dramatic change happened between event 4, followed by the successive expansion of reticulate Nummulites, and event 5. Due to its easy recognition by field methods, the Middle/Late Eocene boundary is traditionally drawn at the base of SBZ 19 (Serra-Kiel et al., 1998), corresponding to event 5 and marked also by the intraphyletic appearance of both Nummulites fabianii and Heterostegina reticulata mossanensis. This change falls, however, within P 15 (planktic foraminifera) and NP 19-20 (nannoplankton) zones, and is therefore considerably younger than the Bartonian/Priabonian boundary placed at the boundary of NP 17/18 zones by planktonic experts.",
keywords = "Eocene, Extinction, Larger benthic foraminifera, Tethys",
author = "G. Less and Ercan {\"O}zcan",
year = "2012",
language = "English",
volume = "105",
pages = "129--140",
journal = "Austrian Journal of Earth Sciences",
issn = "0251-7493",
publisher = "Austrian Geological Society",
number = "1",

}

TY - JOUR

T1 - Bartonian-Priabonian larger benthic foraminiferal events in the western tethys

AU - Less, G.

AU - Özcan, Ercan

PY - 2012

Y1 - 2012

N2 - The composition of Western Tethyan larger benthic foraminifera (LBF) significantly changed as a consequence of the general climate cooling trend in the late Bartonian and Priabonian. Major events are characterized by the disappearance of giant forms of both Nummulites and Assilina and also of the genus Alveolina and some orthophragminid lineages. Simultaneously, radiate and especially reticulate Nummulites, the N. fabianii lineage, and nummulitids with secondary chamberlets such as Heterostegina and Spiroclypeus emerged. Based both on first/last occurrence (FO/LO) data and the evolution of these forms and integrating geological information such as field observations, other LBF and planktonic data, a high-resolution stratigraphy of the Bartonian and Priabonian could be established in the frame of the Tethyan shallow benthic zonation (with SBZ zones and newly erected subzones for SBZ 18 and 19 based on the exceptionally rapid evolution of Heterostegina). We distinguish eight Western Tethyan LBF events in this timespan, mainly based on FO/LO data of selected lineages. These are: (1) FO of the Operculina gomezi-group (SBZ 16/17), (2) FO of genus Heterostegina (SBZ 17/18a), (3) FO of the H. reticulata-lineage (SBZ 18a/b), (4) LO of giant Nummulites (with supposed eastward migration during SBZ 18b-c), (5) FO of genus Spiroclypeus (SBZ 18c/19a), (6) LO of some survivor Middle Eocene orthophragminid lineages (around SBZ 19a/b), (7) FO of Heterostegina with granules (SBZ 19b/20) and (8) LO of the majority of survivor Eocene LBF (SBZ 20/21). The most dramatic change happened between event 4, followed by the successive expansion of reticulate Nummulites, and event 5. Due to its easy recognition by field methods, the Middle/Late Eocene boundary is traditionally drawn at the base of SBZ 19 (Serra-Kiel et al., 1998), corresponding to event 5 and marked also by the intraphyletic appearance of both Nummulites fabianii and Heterostegina reticulata mossanensis. This change falls, however, within P 15 (planktic foraminifera) and NP 19-20 (nannoplankton) zones, and is therefore considerably younger than the Bartonian/Priabonian boundary placed at the boundary of NP 17/18 zones by planktonic experts.

AB - The composition of Western Tethyan larger benthic foraminifera (LBF) significantly changed as a consequence of the general climate cooling trend in the late Bartonian and Priabonian. Major events are characterized by the disappearance of giant forms of both Nummulites and Assilina and also of the genus Alveolina and some orthophragminid lineages. Simultaneously, radiate and especially reticulate Nummulites, the N. fabianii lineage, and nummulitids with secondary chamberlets such as Heterostegina and Spiroclypeus emerged. Based both on first/last occurrence (FO/LO) data and the evolution of these forms and integrating geological information such as field observations, other LBF and planktonic data, a high-resolution stratigraphy of the Bartonian and Priabonian could be established in the frame of the Tethyan shallow benthic zonation (with SBZ zones and newly erected subzones for SBZ 18 and 19 based on the exceptionally rapid evolution of Heterostegina). We distinguish eight Western Tethyan LBF events in this timespan, mainly based on FO/LO data of selected lineages. These are: (1) FO of the Operculina gomezi-group (SBZ 16/17), (2) FO of genus Heterostegina (SBZ 17/18a), (3) FO of the H. reticulata-lineage (SBZ 18a/b), (4) LO of giant Nummulites (with supposed eastward migration during SBZ 18b-c), (5) FO of genus Spiroclypeus (SBZ 18c/19a), (6) LO of some survivor Middle Eocene orthophragminid lineages (around SBZ 19a/b), (7) FO of Heterostegina with granules (SBZ 19b/20) and (8) LO of the majority of survivor Eocene LBF (SBZ 20/21). The most dramatic change happened between event 4, followed by the successive expansion of reticulate Nummulites, and event 5. Due to its easy recognition by field methods, the Middle/Late Eocene boundary is traditionally drawn at the base of SBZ 19 (Serra-Kiel et al., 1998), corresponding to event 5 and marked also by the intraphyletic appearance of both Nummulites fabianii and Heterostegina reticulata mossanensis. This change falls, however, within P 15 (planktic foraminifera) and NP 19-20 (nannoplankton) zones, and is therefore considerably younger than the Bartonian/Priabonian boundary placed at the boundary of NP 17/18 zones by planktonic experts.

KW - Eocene

KW - Extinction

KW - Larger benthic foraminifera

KW - Tethys

UR - http://www.scopus.com/inward/record.url?scp=84863584250&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84863584250&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:84863584250

VL - 105

SP - 129

EP - 140

JO - Austrian Journal of Earth Sciences

JF - Austrian Journal of Earth Sciences

SN - 0251-7493

IS - 1

ER -