From Global Geology to Hydrocarbon Exploration: Ediacaran-Early Cambrian Petroleum Plays of Oman, Pakistan and India

Andrea Cozzi¹, Giuseppe Rea², and Jonathan Craig^3
1Eni India Ltd, New Delhi, India
²Eni Pakistan Ltd, Karachi, Pakistan
³Eni Exploration & Production, San Donato Milanese, Italy

The terminal part of the Neoproterozoic Era (Ediacaran Period) witnessed the transition between supercontinent breakup and reassembly (Rodinia and Gondwana, respectively) and the emergence of the Ediacara fauna after the severe climatic swings expressed by the Cryogenian Snowball Earth-type of glaciations.

In the last decade the sedimentary sequence pertaining to the Huqf Supergroup (Sultanate of Oman) has emerged as the Cryogenian (850-635 Ma) and Ediacaran (635-542 Ma) reference section for the Neoproterozoic of the Middle East Region. A direct litho- and chemostratigraphic comparison of the Huqf Supergroup of Oman with the time-equivalent outcropping successions of the Salt Range in Pakistan and the Marwar Supergroup in western Rajasthan (India) reveals affinities in vertical and lateral facies changes and their timings. The most remarkable fact is that in all the three regions the latest Ediacaran-Early Cambrian sequence starts with a clastic unit (fluvial in Pakistan/India and marine in Oman) followed by a carbonate/evaporitic one with 6-7 basin desiccation cycles that are identical in all the three basins and occurred, as per the dated evaporitic Ara Group of Oman, just before and immediately after the Precambran-Cambrian boundary.

The similar Ediacaran-Early Cambrian tectono-stratigraphic evolution for Oman, Pakistan and India has two major implications: 1) the latitudinal distribution of identical depositional paleoenvironments strengthens the hypothesis that India, Pakistan and Oman were part of a single terrain that progressively got accreted into Gondwana from ~600Ma into the Cambrian; 2) it is expected that the proven oil/gas producing units found in Oman at the base, within and above the Ara Group should be encountered also in the subsurface Punjab Platform of Pakistan and in its indian continuation, the Nagaur-Ganganagar Basin.

Presentation GEO India Expo XXI, Noida, New Delhi, India 2008©AAPG Search and Discovery