10th Meeting of the Saudi Society for Geosciences (SSG10-093) Distribution of Stable Heavy Minerals in Nutaysh Member of Burqan Formation, Midyan Basin, NW Saudi Arabia *Earth Sciences Department, King Fahd University of Petroleum & Minerals, KSA. Binofy@windowslive.com Geology and Geophysics Department, King Saud University, KSA M. Benaafi*, H. Al-faifi Abstract Methodology In Midyan basin ,NW Saudi Arabia, the Early Miocene Nutaysh Member of Burgan Formation exposed and consisted mainly of sub-arkose to sub-litharanite pebbly coarse to medium, sub-angular to sub-rounded, poorly to moderately sorted turbidites sandstone interbeded with mudstone. The studied sandstone deposited in submarine fans. This paper focuses on stable heavy minerals distribution in the sandstone. Four sections selected and sixty nine samples collected for this study. Bromoform is used to separate heavy minerals, then heavy minerals samples examined petrographically using polarized microscope. The heavy minerals occur with low percentage of less than 0.6 % of the detrital grains in the sandstones. The stable heavy minerals including zircon, tourmaline, and rutile are the most dominant, so they are reflecting high cycling process of sedimentation and tectonics activity in the region. Zircon is the main constituent of the stable heavy minerals with an average percentage of 70 % followed by tourmaline 20 %, and rutile 10%. Anhedral grains of zircon are the most dominant in addition to subhedral grains. Tourmaline grains dominated by angular brown in the proximal part and rounded spherical brown and green grains in the distal part of the sandstone. Zircon composition is high at the proximal part of the sandstone and decreases toward the distal part, unlike tourmaline increases toward the distal part. On the other hand, rutile shows no significant changes Field investigation was conducted including measured 4 section and collected 69 samples. Samples were sieved to get very fine sands (63–125 µm).Heavy minerals were separated by using dense liquids techniques (Bromoform, density > 2.8 g /cm).heavy minerals after seperation bound onto a glass slide with Canada balsam, then examined under the polarizing microscope. Zone C Section 1 Zone B Zone B Zone A Zone A Results Section 2 We found that the main stable heavy minerals in Nutaysh member of Burqan Formation are Zircon, Tourmaline and Rutile (ZTR). Zone C Zone B Zone B Zone A Zone A Figure 6: Stable heavy minerals varieties ; 1,2,3)zircon ,4,5,6,7)tourmaline 8,9)rutile. Section 4. Section 3 Figure 5: Illustrated the heavy minerals zones in each section. Introduction Conclusion Nutaysh Member of Burgan Formation located in Midyan peninsula, NW Saudi Arabia (figure 1). It is the sand-rich member (turbidites sandstone interbeded with mudstone) of Burqan Formation(figure 2). This study aimed to investigate the distribution of stable heavy mineral in the sand-rich member of Burqan Formation to enhance the understand of Stratigraphic of studied formation. Amount of Zircon decreased toward the distal part of the submarine fan and in contrast tourmaline increased. Concentration of different stable heavy minerals associated with variation in lithofacies. We found that every section can be divide into heavy minerals zones which assist to understand the stratigraphy of Burqan Formation . Figure 3: Distribution of stable heavy minerals in different parts of Nutaysh Member of Burqan Formation. Section one Section two Acknowledgments The Authors thank King Saud University and King Fahd University of Petroleum & Minerals for all support given to him to finish this research. Also, we thank Professor /Abdullaziz Al-Laboun. References Section four Section three Laboun, A.A., 2012, Did Glaciers Exist during Pleistocene in the Midyan Region, Northwest Corner of Arabian Peninsula?, Arabian Journal of Geoscience, V.5,No.6, PP 1333-1339. Hughes , G.W.,D.perincek.,D.J.Grainger, A. Abu shait,A.M.Jarad.1999.Lithostratigraphy and Depositional History of Part of the Midyan Region, Northwestern of Saudi Arabia.Geoarabia ,V.4,No.4, P.503-542. Huges.G.W, R.S.Johnson., 2005. Lithostratigraphy of the Red Sea Region. Geoarabia, V.10, No.3, P. 40- 126. Mange, M.A., David, T.W., 2007. Heavy Minerals in Use. Development in Sedimentology 58, 1329 P. Figure 2 : Lithostratigraphy of Midyan Region (after Al-Laboun,2012). Figure 1: Geological map of Midyan Basin ,NW Saudi Arabia( After Clark,1986 and Hughes,1999). Figure 4: Distribution of Zircon, Tourmaline and Rutile Minerals in Nutaysh Member of Burgan Formation. 10th Meeting of the Saudi Society for Geosciences Geosciences for Sustainable Development, 15-17 April 2013, KFUPM Campus, Dhahran, Saudi Arabia