Keywords : desert


Petrography and paleoecology of carbonate- phosphatic rocks of Ratga formation (Damlouk member) Akashat Area, western desert of Iraq

Nafi A. Nassar

ANBAR JOURNAL OF AGRICULTURAL SCIENCES, 2009, Volume 7, Issue 2, Pages 14-28

This research covers the detail petrographic study of the rocks of Damlouk member, which represented the middle part of Ratga formation (Eocene) of Akashat area in the western desert of Iraq. This study including the knowldgment of the lithologic and microfacies aspects of this member and also the determination of environmental deposition for each of these microfacies obtained from petrographic analysis. From the field observations and study the rocks in thin sections under the microscope,it is clear that the studied member consist generally of about 40 meter of carbonat_dominated sequence_Rocks types are chalky,marly limestone,fossiliferous limestone with ocasional phosphatic horizons.Detailed petrographic examination of these rocks show that they are characterized by nine distinctive microfacies which include:
1 - L ime mudstone microfacies.
2 - S helly lime wackstone packstone microfacies.
3-Nummulitic lime packstone microfacies .
4-Nummulitic lime packstone to grainstone microfacies .
5-Shelly nummulitic lime packstone microfacies .
6-Foraminiferal lime wackstone microfacies.
7-Oyster_shelly lime packstone microfacies.
8-Bioclastic lime packstone microfacies.
9-a-Phosphatic lime wackstone microfacies .
9-b-Phosphatic wackstone and packstone microfacies .
9-c-Shelly phosphatic lime packstone microfacies.