Abstract:
Karachi Trough is one of the interesting geological features in the Geology of Pakistan. It is an embayment opening up into the Arabian Sea. Geologically, Karachi Embayment is located in the southern most continuation of Kirthar Fold Belt and the southwestern margin of Lower Indus Basin. It is bounded by Ornach-Nal Fault in the west and Hyderabad High in the east. The southern part of the embayment is submerged in the sea and still receiving sediments from different sources. Tectonically, the counter clockwise movement of Indian Plate during Eocene time, after its collision with Eurasian Plate, has resulted in the formation of Karachi Embayment. It has always remained a depression in the past geological time that is characterized by thick Early Cretaceous sediments and also marks the last stages of marine sedimentation in Indus Basin. Paleocene succession is characterized by dominant carbonates, especially in the upper part. Marine carbonates continued to dominate in the Eocene time and Oligocene is marked by dominant clastic facies. Miocene is evidenced by shallow marine limestones. Structurally, it has a large number of structures in the eastern part, where the anticlines are small to large, asymmetrical with steep eastern flank and gentle western limbs. The anticlines in the northern part of the depression are comparatively simple. Hundi and Sari fields are represented by such type of traps. The structural style is NE-SW in the Karachi Trough area. These fields are discovered in Paleocene carbonates, and confirming the Paleocene plays in the area. However, the depression may holds promising targets in Cretaceous and Miocene rocks. This paper describes the wonderful geology and the formation of Karachi Embayment with reference to tectonics and sedimentary fill. The authors suggest careful re-evaluation of the area in order to find the more promising targets for future exploration.
Page(s):
459-468
DOI:
DOI not available
Published:
Journal: Proceedings SPE-PAPG Annual Technical Conference, Volume: 0, Issue: 0, Year: 2004