A revised calcareous nannofossil biozonation for the Lower Jurassic (Hettangian–Lower Pliensbachian) of NW Europe
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A revised calcareous nannofossil biozonation for the Lower Jurassic (Hettangian–Lower Pliensbachian) of NW Europe. / Paulsen, Maria; Thibault, Nicolas; Fraguas, Ángela.
I: Lethaia: An International Journal of Palaeontology and Stratigraphy, Bind 56, Nr. 3, 56.3.4, 2023.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - A revised calcareous nannofossil biozonation for the Lower Jurassic (Hettangian–Lower Pliensbachian) of NW Europe
AU - Paulsen, Maria
AU - Thibault, Nicolas
AU - Fraguas, Ángela
N1 - Publisher Copyright: © 2023 Author(s).
PY - 2023
Y1 - 2023
N2 - The Mochras core, UK, an historic reference site for the study of Early Jurassic cal-careous nannofossils, has been reinvestigated here across the Hettangian to Lower Pliensbachian. Both relative and absolute abundances of 24 calcareous nannofossil species reveal patterns and occurrences that define not less than 37 defined biohorizons. However, due to the low abundance of many of those species towards the base and top of their stratigraphical range, we observe large inconsistencies in first and last occurrences of these species. Instead, we consider records of first consistent and last consistent occurrences (FCOs and LCOs), as well as base and top of acme events, as more reliable biohorizons. Accordingly, we assess the reliability of our biohorizons and show that, in addition to previously established zonal and sub-zonal biomarkers, nine non-zonal biohorizons prove to be robust. Based on that, an updated biozonations scheme with additional subzones for NJB has been proposed and tested against other localities.
AB - The Mochras core, UK, an historic reference site for the study of Early Jurassic cal-careous nannofossils, has been reinvestigated here across the Hettangian to Lower Pliensbachian. Both relative and absolute abundances of 24 calcareous nannofossil species reveal patterns and occurrences that define not less than 37 defined biohorizons. However, due to the low abundance of many of those species towards the base and top of their stratigraphical range, we observe large inconsistencies in first and last occurrences of these species. Instead, we consider records of first consistent and last consistent occurrences (FCOs and LCOs), as well as base and top of acme events, as more reliable biohorizons. Accordingly, we assess the reliability of our biohorizons and show that, in addition to previously established zonal and sub-zonal biomarkers, nine non-zonal biohorizons prove to be robust. Based on that, an updated biozonations scheme with additional subzones for NJB has been proposed and tested against other localities.
KW - Biostratigraphy
KW - Coccoliths
KW - Early Jurassic
KW - Hettangian
KW - Mochras Borehole
KW - Pliensbachian
U2 - 10.18261/let.56.3.4
DO - 10.18261/let.56.3.4
M3 - Journal article
AN - SCOPUS:85175418181
VL - 56
JO - Lethaia: An International Journal of Palaeontology and Stratigraphy
JF - Lethaia: An International Journal of Palaeontology and Stratigraphy
SN - 0024-1164
IS - 3
M1 - 56.3.4
ER -
ID: 382857935