Abstract
AbstractIn order to study the fossil contents of the Abderaz Formation for biostratigraphical purposes the 300 meters thick section was sampled at type section. The sequence is mainly made up of grey shales and marls with two units of chalky limestone in upper part. The lower contact of the formation with Aitamir Formation is disconform while the upper contact with Abtalkh is continuous. There are huge amounts of inoceramids and ammonite. In the chalk limestone bonds of this formation which is belong to Santonian time planktonic, would exist some foraminifera with a less diversity because during the Santonian, the members of morphotype group three (M3) shows a regression in the above-mentioned section, with association of tegilla shapes decreases in the area and sea water. The study of the planktonic foraminifera in isolated form led to differentiate three morphotype groups. The first group is characterized by trochospiral tests usually indicate shallow waters, the second group contains forms with strong ornamentations and the primary keels representing mid waters and finally compact trochospiral tests with keels known as deep water indices are included in the third group. Studies on the morphotypes showed a regressive cycle for Abderaz Formation.
Highlights
In order to study the fossil contents of the Abderaz Formation for biostra ra hical ur oses the meters thick section was sam led at ty e section
The lower contact of the formation with Aitamir Formation is disconform while the u er contact with Abtalkh is continuous
In the chalk limestone bonds of this formation which is belon to Santonian time lanktonic, would exist some foraminifera with a less diversity because durin the Santonian, the members of mor hoty e rou three shows a re ression in the abovementioned section, with association of te illa sha es decreases in the area and sea water
Summary
In order to study the fossil contents of the Abderaz Formation for biostra ra hical ur oses the meters thick section was sam led at ty e section. The sequence is mainly made u of rey shales and marls with two units of chalky limestone in u er art.
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