الملخص الإنجليزي
ABSTRACT
The Permian Gharif Formation is at its most basinal in PDO's concession area in the Hasirah field in west central Oman. The formation comprises an interfingering sequence of shallow marine, clastic-carbonate, lagoonal, river, lake and paleosol deposits. The cores in Hasirah yield Sakmarian fusulinids in the Haushi Limestone, algal facies at the base of the Middle Gharif member and unusual storm deposits in the Upper Gharif (with macroscopic plant remains) which together with ostracod and fish-bearing sediments reflecting the onset of the Khuff Formation marine transgression. This study attempts to relate palynology and palynofacies to these varied sedimentary facies. A locally derived palynological sequence can be tied into the regional biostratigraphic scheme of Stephenson et al. (2003) and Stephenson (2006) and therefore the Hasirah sequence can be correlated regionally. It was also related to subsurface (Angiolini et al. 2004) and surface (Angiolini et al. 2003) macropaleontological studies to allow correlation of Hasirah with surface sequences in the Huqf Outcrop area. A total of 29 samples were analysed from cores in 3 boreholes (Hasirah-1, 10H1 and Hasirah-10H2) located in west central Oman. The taxonomy and stratigraphic distribution of over 50 palynomorph taxa from the Permian rock of Oman has been carried out. Three new species are proposed and these are Vesicaspora sp. B, Lueckisporites sp.A and Ulanisphaeridium sp. A. The palynostratigraphic data indicates OSPZ3b & OSPZ3c assemblages in Hasirah-1H1 (Lower Gharif), ?OSPZ4 assemblages in Hasirah-10H2 (Middle Gharif) and OSPZ5 assemblages in Hasirah 10H1 (Upper Gharif). Correlation with Hilwah-3 and Jufarah-1 (Saudi Arabia boreholes) proved more problematical. Nine palyno facies types were identified b on visual assessment of the percentages of major categories (lath shaped inertinite, equidimensional inertinite, vitrinite, cuticle, amorphous organic matter (AOM) and palynomorphs). During Gharif time, the climate changed from temperate to arid and then tropical. The palynofacies and the sedimentary facies reflect the transgressive - regressive sequences in the Gharif.
