PALEOENVIRONENTS AND SEQUENCE DEVELOPMENT OF THE HARTHA FORMATION, SOUTHEN IRAQ.

Five major environments were recognized within the Hartha Formation in southern Iraq, Theyinclude; supratidal, Shallow restricted marine, Shallow open marine, deep marine, and basinalenvironments. The vertical and lateral distribution of paleoenvironments shows that the Hartha Formation was developed on a homoclinal ramp setting. It is characterized by relatively thick aggradational carbonate succession within the inner ramp and gradual lateral facies changes from restricted to open marine to deep then tobasinal environment. TheHartha succession consists of up to four 4th order cycles, the variation in cycle thickness and composition within the study area reflect variation in the rate of subsidence from one place to another where the tectonic component is the main controlling factor on sequence development. Carbonate deposition continued within the inner ramp (Towards the West) giving a maximum thickness of the formation which consist mainly of supratidal and shallow restricted marine facies. The central part of the study area where accommodation is less in the middle to outer ramp area the sequence consists mainly of Shallow open to deep marine facies, and to the East (basinward) the succession consists mainly of basinal and deep marine facies.