A keynote talk given on the occasion of JK2018, the International Symposium around the Jurassic - Cretaceous Boundary

1. Dual biozonation scheme (benthic foraminifera and
"calcareous" green algae) over the Jurassic - Cretaceous transition:
Another plea to revert the system boundary
to its historical Orbigny's and Oppel's definition
Bruno Granier
The Tithonian-Valanginian interval is subdivided into 5 biozones (zones and subzones) combining mostly large benthic foraminifera and
"calcareous" green algae, which are typical of photozoan assemblages. This dual zonation is calibrated on a sequence stratigraphic
framework for the Jura Mountains where all occurrences of ammonites and calpionellids are plotted. The microfossil diversity was low in
the Tithonian-early Berriasian times; then it significantly increased over the middle-late Berriasian times before a first extinction event at
the Berriasian/Valanginian boundary followed by a second extinction event in the early Valanginian times. The lower/middle Berriasian
and the Berriasian/Valanginian boundaries can be traced consistently from West to East through the whole Tethysian realm. By contrast,
the upper Tithonian and the lower Berriasian cannot be distinguished. Because the location of the Jurassic/Cretaceous system boundary
has been pending a decision of the International Commission on Stratigraphy since 1975, this survey provides one more argument to
abandon the early 20th century Kilian's view which placed it at the Tithonian/Berriasian stage boundary, and to return it to the original
19th century Orbigny's and Oppel's view, i.e., back at the Berriasian/Valanginian stage boundary.
Granier B. (2019).- Dual biozonation scheme (benthic foraminifera and "calcareous" green algae) over the Jurassic - Cretaceous
transition. Another plea to revert the system boundary to its historical Orbigny's and Oppel's definition.- Cretaceous Research., vol. 93, p.
245-274.

2. The goal and the approaches
• How to calibrate microfossil ranges in carbonate
platforms on ammonite or calpionellid scales?
1. The empirical approach
2. The pragmatical approach
The first case to document the conclusions of both
approaches will be the Urgonian case:
1. The starting point is a statement: the Urgonian mostly
corresponds to the upper Barremian – lower Aptian
(“Grenoble school”)
2. Focused analyses of vertical interfingerings and rare
cooccurrences (“Genève school”)

3. A. Arnaud-Vanneau’s chart
The empirical approach

4. B. Clavel’s chart
The pragmatical approach

8. A. Arnaud-Vanneau’s chart

9. A. Arnaud-Vanneau’s chart versus • l’Estellon

10. B. Clavel’s chart versus • l’Estellon

11. The highest discrepancies
appear with Arnaud-
Vanneau‘s (2005). The
best match was obtained
with Clavel‘s (2007, 2010).
What did we learn from • L'Estellon?

12. The transition of the Jurassic
to the Cretaceous in the Jura mountains
Stratigraphic framework derived from
Charollais et al., 2008; Strasky et al., 2014; Strasser et al., 2016
Bernard Clavel
1938-2018

16. Montricher, Vaud, Switzerland

17. Crozet, Ain, France

19. Central Tethys
The central Tethys domain is characterized by rich and
diverse assemblages of benthic foraminifera and
"calcareous" green algae.
5 dual biozones (4 zones and 1 subzone) have been defined
for the Tithonian-lower Valanginian interval:
• the Anchispirocyclina lusitanica zone for the Tithonian-
lower Berriasian;
• the Protopeneroplis ultragranulata subzone for the
upper Tithonian-lower Berriasian;
• the Rajkaella minima zone for the middle Berriasian;
• the Falsolikanella campanensis zone for the upper
Berriasian;
• the Pseudocyclammina lituus zone for the lower
Valanginian pro parte.
• ”)

20. The central Tethys domain is characterized by rich and
diverse assemblages of benthic foraminifera and
"calcareous" green algae.
5 dual biozones (4 zones and 1 subzone) have been defined
for the Tithonian-lower Valanginian interval:
• the Anchispirocyclina lusitanica zone for the Tithonian-
lower Berriasian;
• the Protopeneroplis ultragranulata subzone for the
upper Tithonian-lower Berriasian;
• the Rajkaella minima zone for the middle Berriasian;
• the Falsolikanella campanensis zone for the upper
Berriasian;
• the Pseudocyclammina lituus zone for the lower
Valanginian pro parte.
• ”)
Central Tethys
One cannot discriminate
• upper Tithonian strata from
• lower Berriasian strata

22. Puig Campana, Alicante, Spain
Granier, 1987

23. Azéma & Jaffrezo, 1972
Jaffrezo, 1980
Granier, 1988
Granier, 2019
"Portlandian"
Berriasian ValanginianTithonian
Falsolikanella campanensis
(Azéma & Jaffrezo, 1972)

24. Puig Campana, Alicante, Spain
Granier, 2019

25. T
I
M
E
W Tethys E
“Cosmopolitan”
“Endemic”
Falsolikanella campanensis (Azéma & Jaffrezo, 1972) is a subendemic species,
which is in accordance with a short-ranging (i.e., upper Berriasian)

26. Strong long-ranging
correlation
Strong long-ranging
correlation
Only 2 strong long-ranging
correlations:
• lower-middle Berriasian
• Berriasian-Valanginian

27. T
I
M
E
W Tethys E
“Cosmopolitan”
“Endemic”
For long-distance correlations, one relies on cosmopolitan species,
mostly long-ranging species (F.O. and/or L.O.),
few short-ranging (e.g., Anchispirocyclina lusitanica)

28. European Archipelago

30. TOPLAPS
regression

32. ONLAPS
transgression

33. Extinction 2 Extinction 2
Extinction 1
No extinction!

34. Conclusions
The Tethys domain is characterized by rich and diverse
assemblages of benthic foraminifera and "calcareous"
green algae.
5 dual biozones (4 zones and 1 subzone) have been defined
for the Tithonian-lower Valanginian interval of the
central Tethys:
• the Anchispirocyclina lusitanica zone for the Tithonian-
lower Berriasian;
• the Protopeneroplis ultragranulata subzone for the
upper Tithonian-lower Berriasian;
• the Rajkaella minima and Falsolikanella campanensis
zones for the middle and upper Berriasian;
• the Pseudocyclammina lituus zone for the lower
Valanginian pro parte.
• ”)

35. The Tethys domain is characterized by rich and diverse
assemblages of benthic foraminifera and "calcareous"
green algae.
5 dual biozones (4 zones and 1 subzone) have been defined
for the Tithonian-lower Valanginian interval of the
central Tethys:
• the Anchispirocyclina lusitanica zone for the Tithonian-
lower Berriasian;
• the Protopeneroplis ultragranulata subzone for the
upper Tithonian-lower Berriasian;
• the Rajkaella minima and Falsolikanella campanensis
zones for the middle and upper Berriasian;
• the Pseudocyclammina lituus zone for the lower
Valanginian pro parte.
• ”)
One cannot discriminate
• upper Tithonian strata from
• lower Berriasian strata
Conclusions

36. The Tethys domain is characterized by rich and diverse
assemblages of benthic foraminifera and "calcareous"
green algae.
5 dual biozones (4 zones and 1 subzone) have been defined
for the Tithonian-lower Valanginian interval of the
central Tethys:
• the Anchispirocyclina lusitanica zone for the Tithonian-
lower Berriasian;
• the Protopeneroplis ultragranulata subzone for the
upper Tithonian-lower Berriasian;
• the Rajkaella minima and Falsolikanella campanensis
zones for the middle and upper Berriasian;
• the Pseudocyclammina lituus zone for the lower
Valanginian pro parte.
• ”)
One can “easily” correlate
• the base of the middle Berriasian
• the base of the Valanginian
(i.e., the mark of a first biological crisis!)
Conclusions