Palynology and palynofacies of the Middle Jurassic and Lower Cretaceous successions of northwest Egypt

The present palynological study was performed on 62 cutting samples from the Khatatba, Masajid and Alam El Bueib formations encountered in two wells, Matruh Basin, North Western Desert, Egypt. From the quantitative and qualitative analyses of the studied samples, seven biozones were proposed ranging between Bajocian and Barremian age, which include from young to old: I: Tenua anaphrissa Interval Zone (middle–late Barremian), II: Muderongia simplex Interval Zone (late Hauterivian–early Barremian), III: Systematophora sp. Acme Zone (Valanginian–early Hauterivian), IV: Gonyaulacysta jurassica Interval Zone (late Oxfordian–Kimmeridgian), V: Ctenidodinium continuum Interval Zone (early Oxfordian), VI: Korystocysta gochtii Interval Zone (late Bathonian–Callovian), and VII: Pareodinia ceratophora and Dissiliodinium sp. Assemblage Zone (late Bajocian–early Bathonian). Additionally, six palynofacies assemblages are differentiated and the source rock potential is visually evaluated. The samples from the Alam El Bueib Formation belong to kerogen type III/II of mainly gas prone. It contains immature yellow to orange palynomorphs. The Masajid Formation shows kerogen type II of immature oil prone material. The Khatatba Formation source rock attains the highest levels of source-rock maturity. The upper part of Khatatba Formation (Zahra Member) indicates marginally mature, oil prone organic matter, while the lower part of the Khatatba Formation (Upper Safa, Kabrit, and Lower Safa members) are characterized by late mature organic matter with dark brown palynomorphs. Based on the recovered palynomorphs and palynofacies assemblages, four depositional environments were identified, Fluvio–deltaic, Marginal marine, Proximal inner neritic, and Inner neritic.