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

Chapter one
Introduction
lithologic units during Upper Cretaceous-Lower Tertiary. The following is a
review on the previous studies about lithostratigraphy and biostratigraphy of
the incorporated formations.
1.4.1- Upper Cretaceous Formations
Bellen et al., (1959), Ditmar et al., (1971),Kassab (1974 & 1975), Buday
(1980),Karim (2004), Jassim & Goff (2006) and others defined the Upper
Cretaceous cycles as the Upper Campanian –Maastrichtian sedimentary cycle
based on the ages attributed to the Shiranish and Tanjero Formations at their
type localities and the other similar rock units. Fig (1.3)
1.4.1.1- Shiranish Formation
The Shiranish Formation was first defined by Henson (1940) from the High
Folded Zone of North Iraq, near the village of Shiranish Islam, Northeast of
Zakho. The formation belongs among the most widespread units to the Upper
Campanian- Maastrichtian cycle in North Iraq. It is represents distal portion of
deeper foreland basin near by its neighboring Tanjero Formation too Karim
(2004). The Formation, in its type area, comprises thin bedded argillaceous
limestones (locally dolomitic) overlain by blue pelagic marls (Owen and Nasr,
1958; Bellen et al., 1959, in Jassim & Goff. 2006). Al Qayim, (1992), divided
the formation into three lithologic units in its type locality.
The Shiranish Formation is also recognized in NE Syria (Dubertret, 1966
and Brew et al., 2002 in Jassim & Goff. 2006). Maastrichtian foraminiferal
limestone and marl in central Syria can be partly correlated with the Shiranish
Formation (Ponicarov et al., 1967 in Jassim & Goff. 2006). Al Mutwali and Al
Juboury (2005) studied Shiranish Formation from Sinjar area, northwestern
Iraq and lithologically they are divided into three units; these units embrace an
alternation of marl, marly limestone, limestone, sandy limestone and lenses of
breccia. In SE Turkey the Shiranish Formation is equivalent to the Kermav
marls of the Mardin area (Beer 1966 in Buday, 1980). Towards, the SE of Iran
the formation is equivalent to the upper part of pelagic Grupi Formation
(James & Wynd 1965), and the Upper Cretaceous Marl Group it is equivalent
to Tayrat Formation from Kuwait and Upper part of Aruma Formation in Saudi
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