THE STRATIGRAPHY OF THE EXPOSED CRETACEOUS ROCKS IN IRAQ, AS DEDUCED FROM THE RESULTS OF THE REGIONAL AND DETAILED GEOLOGICAL SURVEYS (GEOSURV 1971-1996)

Abstract

The Cretaceous rocks, in Iraq, are characterized by their well development all over the country, on the contrary to the rocks of other geological periods. The Cretaceous rocks are exposed widely in the Iraqi Western Desert, as well as in the northeastern and northern parts of the country. They are also exposed in Sinjar and Qara Chauq mountains. The main rock types are carbonates, marl, phosphorites, shales and fine clastics. Conglomerates are also known, but only in the northeastern part of the country. Igneous complexes and metamorphic rocks are limited to the northeastern part of Iraq. The thickness of the Cretaceous rocks is highly variable, not only in different parts of Iraq, but even in one single formation. As a whole, the thickness decreases towards southwest of the country.