Variation of the modal percentages of epidote in recent sediments from selected localities in Northern Iraq

الملخص EN

The metastable detrital epidote in northern Iraq is one of the non-opaque heavy minerals found in the Recent sediments of Tigris River and its tributaries, in addition to other rivers and valleys.

The petrography revealed that the detrital epidote minerals are dominantly epidote (synonym pistachite), and less abundant zoisite and clinozoisite.

Generally, the detrital epidote in the fluviatile sediments constitutes high frequency in most of the selected localities, with an average of 22 %.

Some localities, especially Lesser Zab River has the highest content of 42.6 %, whereas the lowest content is found in Gomel Al-Khazir of 2.5 %.

By comparing the average of the detrital epidote determined in this study with those averages given by other workers, it seems to be approximately similar to that in the Recent sediments of the main channels of Tigris River (24.4 %) and Shatt El-Arab (25.8 %), but of lesser value compared with that of Euphrates River (33.7 %).

The greater difference is noticed in the average content of detrital epidote when compared with that of Aqsu and Adhaim Rivers (66.7 %).

The present study has determined also the main factors controlling the deposition of detrital epidote together with other heavies.

The discussion of the provenance of the detrital epidote revealed that they are most probable products of disintegration of metamorphic rocks essentially, or from metamorphosed igneous rocks, both rock types are of Zagros- and Taurus Ranges in Iraq and Turkey respectively.

Moreover, the recycling of the older formations (Kolosh, Tanjero, Injana, Mukdadiya and Bai Hassan) and river terraces, which have had relatively high content of detrital epidotes as documented by many authors.