Stable carbon and nitrogen isotopes and elemental composition and origin of organic matter from the Euphrates, Injana and Dibdibba formations in Iraq: discrimination between marine and terrestrial environments

Abstract

Awadh, S.M., 2014. Sta ble car bon and ni tro gen iso topes and el e men tal com po si tion and or i gin of or ganic mat ter from the Neo gene Eu phra tes, Injana and Dibdibba for ma tions in Iraq: dis crim i na tion be tween ma rine and ter res trial en vi ron ments. Geo log i cal Quar terly, 58 (4): 729-736, doi: 10.7306/gq.1174 Three Neo gene sed i men tary for ma tions re flect ing dif fer ent depositional en vi ron ments have been in ves ti gated for the purpose of di ag nos ing the iso to pic source of the sed i men tary or ganic mat ter and their palaeoenvironmental sig nif i cance in discrim i nat ing be tween ma rine and ter res trial en vi ron ments. One of these for ma tions is com posed of car bon ate and marl of a shal low-ma rine en vi ron ment (Eu phra tes For ma tion), and the other for ma tions are com posed of a clastic ter res trial (fluviatile) de pos its with some dif fer ences in the depositional con di tions (Injana and Dibdibba for ma tions). The iso to pic d 13 C%, d 15 N% val ues, or ganic car bon (OC) and to tal ni tro gen con tents, and atomic C/N ra tios are used as ev i dence of depositional en vi ronment. Av er age d 13 C val ues (in ‰) for the Dibdiba, Injana and Eu phra tes for ma tions are -25.4, -25.7 and -24.5, re spec tively; av er age d 15 N val ues (in ‰) are 4.44, 5.24 and 7.24 and av er age OC (in wt.%) is 0.13, 0.3 and 1.1, re spec tively. A sig nif i cant vari a tion in the sta ble car bon and ni tro gen iso tope com po si tions be tween flu vial and ma rine de pos its was re corded. The d 13 C, d 15 N and C/N val ues in di cate that the or ganic mat ter in the Eu phra tes For ma tion is of ma rine or i gin, whereas it is of terres trial or i gin (fluviatile) in the Injana and Dibdibba for ma tions. The C/N atomic val ues are mostly high in the Injana (37) and Dibddiba for ma tions (51), sug gest ing greater in put and/or pres er va tion of ter res trial or ganic mat ter de rived from land plants; the shal low-ma rine en vi ron ment (Eu phra tes For ma tion) was char ac ter ized by a low C/N ra tio (9) due to the al gal-de rived organic mat ter with lim ited in put of ter res trial or ganic mat ter.Key words: sta ble car bon iso topes, sta ble ni tro gen iso topes, or ganic mat ter, ma rine en vi ron ment, ter res trial en vi ron ment, palaeoenvironment, Iraq.

Manufacture of Portland Cement from Claystone of Nfayil Formation Middle Miocene, in Southern Desert of Iraq

“…2). The Euphrates, Nfayil, Injana and Dibdibba formations cropping out in the zone of Abu jir fault, is good evidence for interpreting the fault activity (Al-Dabbas et al, 2013;Awadh, 2014;Awadh and Muslim, 2014;Awadh el.al. Awadh, 2018;Al-Dabbas et al, 2019;Awadh and Al-Owaidi, 2020).…”

Natural Radioactivity in Soil and Bitumen in Al-Marj Spring and Abu-Jir Village, Anbar, Western Iraq

“…It is restricted between latitudes (33°15ʹ33.30ʺ-33°41ʹ46.40ʺ N) and longitudes (42°43ʹ57.33ʺ -42°54ʹ11.0ʺ E) (Table 1). The stratigraphic succession of the area is represented by the Euphrates Formation (Early Miocene) composing of carbonates with little of clay minerals (Al-Dabbas et al, 2014 andAwadh, 2014), Fatha Formation (Middle Miocene) which is characterized by predominant evaporate facies comprised of anhydrite, gypsum, and salt, interbedded with limestone, marl, and relatively fine-grained clastics (Al-Obaidy, 2015), and Quaternary sediments which comprised from the Pleistocene and Holocene. The Pleistocene sediments are heterogeneous of fine pebbles consisting of quartz, chert, carbonate rock fragments, and clay (Awadh and Ahmed, 2013).…”

Sequence Stratigraphy of the Fatha Formation in Shaqlawa Area, Northern Iraq

“…Strontium isotopes have dated the base of the Gachsaran Formation in Iran, which is thought to be comparable to the Fatha Formation in southern Iraq, as Early Miocene, Mid-Burdigalian (Ehrenberg et al, 2007). The Fatha Formation is emplacement on the Euphrates Formation and both are of wide spread exposures Awadh and Ahmed, 2013;Awadh, 2014). The Fatha Formation was deposited in lagoon environment over basinal facies (Al-Dabbas et al, 2013;Al-Dabbas et al, 2014;Awadh and Al-Ankaz, 2016b;Awadh and Al-Ankaz, 2016c).…”