Abstract
Ten dredge samples and three piston cores collected from the head and the central part of the Persian Gulf were analyzed for clay minerals. Illite plus a random mixed-layer of illite-montmorillonite with approximately 10-20% expandable layer and chlorite are the principal constituents in the clay mineral assemblage. Montmorillonite is distributed widely but less in the amount, and kaolinite is present in the least amount. These clay minerals seem to be of terrigenous origin. There are two possible sources of these clay minerals: the Tigris, Euphrates, and Shatt-Al-Arab Rivers of Iraq which enter into the head of the gulf, and numerous streams flowing the Zagros Mountain area in the coast of Iran.
The constancy of the clay mineral composition with depth in each core taken from the head of the gulf suggests that the source areas for the clay mineral have remained unchanged for a long time, probably since the Late-Pleistocene, and changes in the environment have not brought about any diagenetic change in the sediment.
