Ordovician–carboniferous palynology of el-waha-1 borehole, western desert, Egypt

Abstract

<span style="font-size:11.0pt;mso-bidi-font-size: 10.0pt;font-family:" times="" new="" roman","serif";mso-fareast-font-family:"times="" roman";="" letter-spacing:-.1pt;mso-ansi-language:en-gb;mso-fareast-language:en-us;="" mso-bidi-language:ar-eg"="" lang="EN-GB">Diverse acritarchs, chitinozoa, and miospore assemblages were recovered from the Paleozoic sequence in El-Waha -1 well, north western part of the Western Desert. Assemblages have many previously described forms known from the Paleozoic strata in north Gondwana and other parts in the world. The study revealed that the sedimentation was repeatedly interrupted , as is confirmed by stratigraphic breaks. It revealed also that the Ordovician assemblage as well as the lower part of the Silurian are composed mainly of acritarchs, less chitinozoans and no miospores have been recorded. Real sporomorphs are recorded only at the upper part of the Silurian with smooth spores (<i>Retusotriletes, Ambietisporites, Archaeozonotriletes</i>), verrucates ones, and <i>Emphanisporites</i> with poorly defined ribs. Early Devonian is characterized by zonate – camerate, pseudosaccate, a relatively simple spore types and verrucate ones, that is beside a considerable increase in diversity of the phytoplankton. Middle Devonian shows the first incoming of small sculptured camerate spores with thick exospores wall and large spinate forms related to genera <i>Hystrichospora, Grandisporites </i>and<i> Ancyrosporites</i>. Early Carboniferous is dominated by vascular plant taxa (Ferns) including laevigate, cingulizonate and cavate forms. No saccate pollen grains (Gymnosperms) have been recorded in the studied interval.</span>