Journal of Earth Science & Climatic Change
Open Access

Abstract

Advanced techniques such as scanning electron microscope hot-cathodoluminescence (SEM-CL) and electron microprobe analysis (EMPA) as well as petrography are applied to investigate the paragenetic sequence and provenance of intertidaltidal flat sandstones of the Ora formation which is exposed in northern Iraq. The formation consists mostly of supermature quartzarenites with subordinate immature subarkoses and sublitharenites. The mean framework composition of the thinly bedded sandstones of Ora Formation is Q95.7F2.8R1.4 where 90% of the quartz grains are monocrystalline and texturally supermature. Meanwhile the mean composition of the thickly bedded sandstones is Q85.4F9.7 R4.8 with 84% of the quartz grains are monocrystalline and texturally immature. The provenance of the Ora sandstones is dominantly craton interior and less recycled orogeny. The Ora formation has undergone intensive and complex episodes of eogenesis, mesogenesis, and telogenesis. Compaction and quartz cementation is more dominant than other diagenetic processes evident from tight grain supported fabric which predated authigenic illite formation; this is also evident from close packing of detrital framework that resulted in reduction of primary porosity. Albitization has postdated eogenesis of K-feldspar cements. Cathodoluminescence study indicated four main distinctive fabrics in quartz grains, (1) healed fractures, (2) mottled textures, (3) low-intensity dark CL streaks and patches, and (4) shocked quartz. The results indicate the dominance of brown to dark blue CL for quartz of low-temperature metamorphic origin; bright blue colors for the felsic plutonic and high-temperature metamorphic quartz; with considerable amounts of detritus that has originated from felsic and mafic volcanic rocks and are characterized by red, violet colors luminescence.

Biography

Muhamed Fakhri Omer is a Lecturer at Geology Department-Salahaddin University in Erbil-Iraq since 2002. He got MSc in 2000 and PhD in 2012 at Baghdad University on Paleozoic Formations which are exposed at mountains of Northern Iraq. He is expert in cathodoluminescence and scanning electron microscopy that was obtained through three months training course at Aarhus University in Denmark in 2011. He got Postdoctoral scholarships for one year at Warsaw University, Poland in 2014. He participated in many local and international conferences with oral presentations; the last one was the 2nd international conference on GEOShale held in Warsaw (Poland) in September 2014. He published many papers in the Journal of African Earth Science in 2014 and 2015. He has been serving as a reviewer in many international journals.

Email: muhfakhri2005@gmail.com