biostratigraphy and paleoecology of cretaceous/tertiary boundary in ...

Chapter one
Introduction
a- Globotruncana fornicata –stuartiformis-elevata-roseta- ventricoza Zone.
1- Globotruncana calcarata-- elevata--aegyptiaca Subzone (Late Campanian)
2- Globotruncana arca – tricarinata - subcircumnodifer Subzone (Early
Maastrichtian)
b - Globotruncana contusa- esnehensis- duwi Zone
1- G. gansseri- bahijae- Gublerina cuvillieri Subzone (Middle Maastrichtian)
2- Abathomphalus mayaroensis Subzone (Late Maastrichtian)
3- Globotruncana falsocalcarata Subzone (Late Maastrichtian)
Abawi et al., (1982) and Abdel-Kireem (1986a &b) included both formations
within stratigraphy of Upper Cretaceous in northeast Iraq, and they recognized
five planktonic foraminiferal subzones under two zones as follow from the base
to the top:
a- Globotruncana fornicata-arca-stuarti Assemblage Zone
Globotruncana calcarata Subzone (Late Campanian)
b- Globotruncana aegyptiaca –lapparenti-stuarti Assemblage Zone.
1- Rugotruncana subcircumnodifer Subzone (Early Maastrichtian)
2- Globotruncana gansseri Subzone (Middle Maastrichtian)
3- Globotruncana contusa Subzone (Middle Maastrichtian)
4- Abathomphalus mayaroensis Subzone (Late Maastrichtian)
Al-Mutwali and Al-Jubouri (2005) determined the age of Shiranish
Formation by Late Campanian—Late Maastrichtian through the biostratigraphy
of the following biozones
1- Globotruncana calcarata (Late Campanian)
2- Globotruncanella havanensis- Roseta fornicata Zone (Early Maastrichtian)
3- Globotruncana aegyptiaca Zone (Early Maastrichtian)
4- Globotruncana gansseri Zone (Late Maastrichtian)
Bakkal et al., (1993), studied biostratigraphy of Shiranish Formation in
Higran area, and determined the age of Shiranish Formation as Middle —Late
Maastrichtian, by recognizing two planktonic foraminiferal subzones of
Globotruncana gansseri gansseri and Kassabiana falsocalcarata subzones
under the Globotruncana contusa stuartiformis biozone.
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