SUPERSEQUENCE FRAMEWORK AND THE RELATIVE SEA-CHANGE OF THE PHANEROZOIC SEDIMENTARY COVER OF THE PERSIAN PLATFORM

Over 20 km of strata ranging in age from Late Precambrian to Recent were deposited on the Persian Platform, now exposed in the Zagros Mountains of Iran. Recognition of major sedimentological packages and reconstruction of relative sea-level change of the Zagros region can assist in understanding of crustal evolution of the Tethyan region.

Twelve supersequences bounded by major, regional unconformities are recognized in the Zagros region. They include: (1) Kourosh (Late Precambrian to Early Ordovician), (2) Camboojiyeh (Early Ordovician to Late Silurian), (3) Darioush (Early to Middle Devonian), (4) Sooshiant (Middle Devonian to Carboniferous), (5) Khashayar (Early to Late Permian), (6) Ashk (Early to Middle Triassic), (7) Farhad (Early to Late Jurassic), (8) Mehrdad (Early Cretaceous), (9) Ardavan (Late Cretaceous), (10) Ardeshir (Early Paleocene to Early Oligocene), (11) Shapour (Middle Oligocene to Early Pliocene), and (12) Khosrow (Early Pliocene to Recent).

Supersequences and the inferred second-order relative sea-level change of the Persian Platform correspond very well with the Exxon's global chart, suggesting that the relative sea-level fluctuation was the main control on sequence development. Marine source rocks were deposited during Middle and Late Ordovician, Early and Middle Silurian, Late Jurassic, Early and Late Cretaceous, Paleocene, and Eocene when rapid sea-level rise flooded the platform. Intense fracturing has produced reservoirs from strata of all ages.