Provenance and Origin of the Sand Dunes Sediments in the Na’ama Area / Southeast Tikrit City Northern Iraq

Abstract

Study of three Barchan sand dunes in Na'ama area southeast Tikrit city have been carried out for (10) samples, the investigation included petrographical, mineralogical and geochemical aspects of the sand dunes from grain size point, the sand grains are commonly sub-rounded to sub-angular forming about (98.8%) with (1.2%) of mud. Petrographically, the sand are sub-litharenite to lithic arenite and mineralogical analysis indicated that most of sand dunes are mainly consist of quartz and carbonate rock fragments in addition to rare feldspar and mica where quartz prevail the mineralogy of all sand dunes due to the selective wind sorting which concentrates more quartz grains, and to the aeolian weathering activity which has depleted the feldspar grains through subaerial collisions. Fine grained mean grain size, very well to moderately sorted, near symmetrical skewness with leptokurtic distribution are characterized the sand dunes in the study area. These statistical parameters show that the sand dunes are extremely controlled by sedimentary sources (Injana Formation sediments). Also, the rarities of organic materials within the sand dunes indicate to the rarity of coverage plant within the seasonably moved sand dunes.
 Several transparent heavy minerals are identified in the sand dunes such as Tourmaline, Hornblende, Olivine, Chlorite, Ankerite and Zircon with well rounded edges due to the transportation, in addition to opaque heavy minerals of iron oxide like Magnetite, Hematite and Chromite concentrated within sand fraction. Atomic absorption analysis distinguished many types of major and trace elements in the sand dunes too. These heavy minerals and trace elements refer to that the sand dunes were derived from ancient igneous and metamorphic rocks which eroded and deposited later within Injana Formation