Paleoecology, palynofacies, thermal maturation and hydrocarbon source-rock potential of the Jurassic-Lower Cretaceous sequence in the subsurface of the north Easern Desert, Egypt

Abstract

The Jurassic to Lower Cretaceous sequences in the wells Abu Hammad-1, Q-71-IX and Kabrit-1, north Eastern Desert of Egypt, have yielded palynofacies assemblages of varying composition. Seven palynofacies types which are environmentally controlled are identified and the source rock potential is evaluated. Eight formations are paleoecologically studied using spores, pollen grains, dinoflagellate cysts and other paniculate organic matter. The lower part of the Rajabiah Formation (Toarcian-Aalenian) was formed in shallow marginal marine or sabkha environment, while the upper part of the Rajabiah and the Shusha formations were deposited in shallow marine environment (inner shelf) under warm subtropical climatic conditions. The deposition of the Bir Maghara Formation is believed to be deposited in shallow marine environment of the inner to middle shelf. The deposition of the mixed clastic and carbonate sequence of the Khatatba Formation (Bathonian-Callovian) was took place in the middle to outer shelf conditions (30-100 m). The Masajid Formation (latest Callovian-Kimmeridgian) is a massive carbonates succession with intercalated shales that was deposited in normal marine conditions of the outer shelf to upper slope (100-600 m). The siliciclastic deposits of the Alam El Bueib Formation (Barremian-Aptian) were accumulated in near shore to inner shelf (<30 m) environment, under arid to semiarid conditions. The deposition of the Alamein Formation (Aptian) may have taken place in shallow marine environment of the middle shelf, while the elastics of the Kharita Formation (Lower Albian) may have been deposited in the inner shelf environment. Spore/pollen colour is used to discriminate the organic maturation levels and thermal alteration for the

يتناول هذا البحث نتائج السمحنة العضوية البالينولوجية لصخور عصري الجووامي والطباشيري السفلي التحمت سطحية لابار أبوحماد .