Source Rock of the Volcanic Fragments in Wadi Al-batin, Iraq: Geomorphological, Petrographical and Geochemical Evidences

Abstract
Geomorphologically, Wadi Al-Batin is a natural extension of Wadi Al-Rummah, which begins at the west and north-west highlands of Saudi Arabia. At the end of Wadi Al-Batin, a massive sedimentary delta "Alluvial Fan" covers large parts of Kuwait and south eastern Iraq. Wadi Al-Batin is the main responsible for the transfer of many types of igneous rock fragments and sediments to Iraq and Kuwait. The rock fragments dispersed in Wadi Al-Batin and its fan, SE Iraq include two volcanic rock verities associated with clastic sediments and nodular chert: (1) red colored fragments are mainly rhyolite and dacite of calc-alkaline peraluminous nature and display geochemical characteristics of anorogenic within-plate environments, and (2) dark colored fragments are basalt and banded rhyolite. Basalt suffered from notable geochemical and mineralogical effects of alteration leading to misleading classifications although; it is tholeiitic peraluminous and reflects the geochemical characteristics of orogenic arc-type. Petrographic and geochemical evidences indicate that the black dacite and trachyte rocks are actually basalt or andesite. Previous geomorphological, hydrogeological and environmental studies indicate that, the annual flood flows through the tributaries of the Al-Rummah Basin then connect to Wadi Al-Batin since Pleistocene till now carrying a heavy load of rock fragments and sediments from the high lands of W and NW Saudi Arabia; specifically from Ha'il and Al-Qassim then deposit them in areas of low altitude in Iraq and Kuwait in Wadi Al-Batin and his alluvial fan. There are several petrographic and geochemical similarities between Wadi Al-Batin rhyolites and some rhyolites in NW Saudi Arabia, especially from the areas around Ha'il, (namely Hadn formation type locality, Jabal Aja and Sarrah alkali rhyolite) and Al-Qassim, (namely Jabal Aban al Asmar “Samra rhyolite”). These results suggest that the volcanic rock fragments at Wadi Al-Batin derived from spatially two different suites of W and NW Saudi Arabia, especially from these areas in Ha'il and Al-Qassim which represent the upstream of Wadi Al-Batin watershed.