Journal of African Earth Sciences ( IF 1.603 ) Pub Date : 2021-02-22 , DOI: 10.1016/j.jafrearsci.2021.104157 Aya Raafat; Sameh S. Tahoun; Nabil M. Aboul Ela
A palynological study of 35 cutting samples from the Middle Jurassic–Lower Cretaceous section encountered in the OBA D-8 Well in the north Western Desert of Egypt yielded palynomorphs and particulate organic matter used to interpret the biostratigraphy, palynofacies, paleoenvironment, thermal maturation, and hydrocarbon potential of the Matruh Basin. The stratigraphically significant dinoflagellate cyst and sporomorph taxa recovered, which include Murospora florida, Aequitriradites spinulosus, Pilosisporites trichopapillosus, Callialasporites trilobatus, Tenua anaphrissa, Muderongia simplex, Systematophora sp., Gonyaulacysta jurassica, Korystocysta gochtii, Pareodinia ceratophora, and Dissiliodinium sp., permit an age assignment of the studied section as Bajocian to Aptian. Seven formal dinoflagellate cyst zones and four formal sporomorph zones are proposed for this time interval, in addition to differentiating four palynofacies assemblages and using the Rock-Eval Pyrolysis method to visually and geochemically evaluate the source rock potential. The 0.45-2.82 wt% TOC values of the studied samples indicate fair to good source rocks. An inner neritic depositional environment due to relatively high sea level is deduced for the Khatatba and Masajid formations using palynological proxies, as reflected in the lower percentages of sporomorphs relative to dinoflagellate cysts. During the Lower Cretaceous, a predominance of terrestrial sporomorphs in the Alam-El Bueib Formation suggests the advance of a fluvio-deltaic environment, possibly related to a significant sea level fall and regressive phase.
中文翻译:

埃及马特鲁盆地OBA D-8井巴约期至Aptian演替的古孢粉生物地层学,古相,热成熟度和古环境解释
对埃及西北沙漠OBA D-8井中侏罗系-下白垩统剖面的35个切屑样品进行的孢粉学研究,产生了古孢粉和颗粒状有机物,用于解释生物地层学,古岩相,古环境,热成熟度和马特鲁盆地的油气潜力。该地层显著甲藻囊肿和sporomorph类群恢复,其中包括Murospora佛罗里达,Aequitriradites spinulosus,Pilosisporites trichopapillosus,Callialasporites trilobatus,Tenua anaphrissa,Muderongia单纯,Systematophora属,Gonyaulacysta jurassica,Korystocysta gochtii,Pareodinia ceratophora和Dissiliodiniumsp。,允许将所研究部分的年龄分配为Bajocian到Aptian。在这个时间间隔内,除了区分四个古孢子组合并使用Rock-Eval热解方法从视觉和地球化学角度评价烃源岩的潜力外,还建议在这个时间间隔内形成七个正式的鞭毛藻类囊肿区和四个正式的孢子样区。所研究样品的TOC值为0.45-2.82 wt%,表明源岩为中等至优质。利用孢粉学推论,推论了哈塔特巴和马萨季德组的海平面相对较高的内部胶质沉积环境,这反映出孢子体相对于鞭毛囊肿的百分比较低。在下白垩纪期间,Alam-El Bueib组的陆生孢子体占主导地位,这说明了河流-三角洲环境的发展,