Encrusting foraminifera from the miocene reefs of Sinai, Egypt: A significant paleobiogeographic affiliation

Abstract

First attention is offered to encrusting foraminifera existing in the Miocene reefal deposits of Wadi Gharandal (Sinai, Egypt). The detected encrusting foraminifera are confined to typical reefal limestone development. They belong mainly to the acervulinid, planorbulinid and homotrematid groups; dominated entirely by Tayamaia and Gypsina. Moreover, other forms include Neoplanorbulinella, Planolinderina, Borodinia, Discogypsina, Ladoronia, Sphaerogypsina and Sporadotrema. Besides, they inhabit different paleoenvironments; reef-flat, fore-reef and back-reef lagoonal conditions. This encrusting assemblage shows close paleobiogeographic affinity to the West Pacific region that locates at the same paleolatitudinal position. Consequently, such strong affiliation and copious faunal exchange certainly require direct and short distance connection and water inroad of an assemblage likely indicative for warm temperate to tropical settings. Therefore, the prior marine connection that dubiously proposed by Rögl (1999) in the Early Oligocene, extending north of India, west-east direction from eastern Mediterranean passing through east Iran and expanded directly across Asia to West Pacific is proposed to be the best direct and shortest water connection to the W. Pacific realizing this rigorous faunal similarity. On consequence, this connecting sea is thought to continue open even during Aquitanian and its closure had started in Early Burdigalian time. This closure is synchronous with the analogous restriction of the central basins of Iran which is considered the entry passage to W. Pacific across the proposed connecting sea. The results significantly provide an evidence for interruption also during the Early Burdigalian.