Abstract
Analysis of the foraminiferal contents of twenty cutting samples from the subsurface section of well D2-NC41, offshore NW Libya, covering the Middle Miocene-lowermost Pliocene Al Mayah (part) Tubtah, Marsa Zonaghah, and Sbabil (part) Formations, has resulted in the recognition of 38 planktonic and 85 benthonic foraminiferal species. Planktonic Foraminifera at the lower part of the section indicate Zone N8 of Blow (1969, 1979) of Langhian age (= Praeorbulina glomerosa glomerosa Zone). Zones N9-N18 indicating Serravallian - lowermost Lower Pliocene are not precisely determined due to the lack of planktonic Foraminifera. The lower part of the section is relatively rich in planktonic Foraminifera (25 species) indicating deep water paleoenvironment. Upward the section a noticeable decrease and/or absence of planktonic Foraminifera, and the increase and/or first appearance of benthonic foraminiferal species Elphidium spp., Peneroplis spp., Borelis melo, and Quinqueloculina spp. would indicate continuous shallowing during the deposition of the upper Al Mayah Formation (Serravallian), the Tubtah Formation (Tortonian), and the Marsa Zouaghah Formation (Messinian). The Shabil Formation (Pliocene) deposition commenced with more deep marine environment indicated by the new appearance of planktonic Foraminifera.