Systematics and Biostratigraphy of the Middle Ordovician to Lower Silurian Chitinozoans of the Tabuk and Qasim Areas of the Arabian Peninsula

Chitinozoans from seven water wells, located in the Qasim and Tabuk areas of Saudi Arabia, have been investigated. Five local chitinozoan biozones have been recognized, representing Middle Ordovician to Lower Silurian levels of Arabia. In general, the chitinozoan faunas belong to the Gondwanaland realm. However, Caradocian and Ashgillian chitinozoans seem to have been distributed in a cosmopolitan manner. Ranges of the species encountered have been established.

Stratigraphy, depositional environment and paleoecology of the Lower Paleozoic sediments of Arabia have also been discussed here. For the first time, separate Caradocian and Ashgillian units in Arabia have been recognized based on their chitinozoan composition. This study also proves that chitinozoans attain their maximum abundance and diversity in cold water environments.