**1. Introduction**

The Kolosh formation is studied here for the first time in the Badelyan area in the NE extremities of the high-folded zone, very near to the suture of the NZTB (**Figure 1**) [1], which is widely distributed in NE Iraq. It consists of successive

sandstones and mudstones interbeds [2]. The previous workers suggested no signs of turbidites and graded beddings in the formation and classified them as molasses sediment deposited in a narrow platform basin [3–5].

Ophiolite sandstones are very rare in the world, which was reported in Italy (Val Marecchia Nappe) composing high percentages of serpentine and ultrabasic fragments [6]. The ophiolite sequence is considered as the main source of intrusive ultrabasic/basic and basic volcanic grains are basically derived from mantle, oceanic crust, and from volcanic arcs. The green sand is composed of relatively high percentages of olivine grains that were recently recorded only in the Hawaii Islands, where the lava flows are composed of olivine basalt type [7]. High active storm and submarine waves made rapid erosion and deposition of the heavy fractions, for example, olivine grains in the shallow environment.

This chapter discusses sandstone units of the Kolosh formation, which contain high percentages of fresh olivine, pyroxene, and ultrabasic/basic igneous grains as an unusual case in Iraq and in Neotethys extension. It tries to interpret the potential

#### **Figure 1.**

*The geological map of Dyana-Rawandoz-Sidakan-Rayat areas in the suture of the Zagros thrust belt NE Iraq shows the study area (rectangular) (Geol. map of Erbil and Mahabad GEOSURV, compiled by Sissakian et al. [1].*

*Abnormal Ophiolite (Olivine/Pyroxene Rich) Sandstone NE Iraq: An Approach to the Origin… DOI: http://dx.doi.org/10.5772/intechopen.108333*

source rocks of the olivine and pyroxene concentration related to tectonic thrusting and the mode and mechanism of deposition. The paper studied the facies and associations relative to tectonosedimentary evolution in response to thrusting tectonism and seismicity. Arrangement of the facies sequences of the Kolosh formation in the studied area refers to deep marine turbidites rejecting the previous suggestion of no turbidities and no graded beddings. The turbidites facies is supported by characteristic sedimentary structures of turbidity origin as discussed later.
