ÇAĞRILI KONUŞMALAR / KEYNOTES Invited Speeches ... - TPJD

Stratigraphic Framework of the Saudi Arabian Cambrian - Ordovician
Successions, and Correlation with SE Turkey in the Arabian Platform
Muhittin Şenalp 1 , Nihat Bozdoğan 2
1 Retired
2 Turkish Petroleum Corporation, Research Senterc Ankara
Being an asymmetric wide basin, Arabian Plate deepens towards the east and reaches its
maximum depth in the Zagros Collision Zone.
The oldest Paleozoic succession is the Early Cambrian Siq Formation, a fluvial to marine deposition
that consists of thick, red colored sandstones. During the Middle Cambrian, regionally Arabia
and Turkey were under the shallow marine conditions represented by a carbonate-dominated
sequence with clastic interbeds. Named as Burj Formation in Jordan and Arabia and as Koruk
Formation in SE Turkey, this sequence is a key level in the region.
By the rapid uplifting of the Arabian Shield, the carbonate deposition was disrupted in Late
Cambrian and continental clastics started to deposit around Saudi Arabia, Jordan and SE Turkey.
Beginning with conglomeratic sandstones and poorly sorted conglomerates consisting of
magmatic rock fragments in the lower parts, the sequence gradually changes into medium-tocoarse
grained, cross-bedded fluvial sandstones in Saudi Arabia. This unit is correlated with the
Sosink Formation in Turkey.
The boundary between the Cambrian and Lower Ordovician successions is a sharp transgressive
contact in Saudi Arabia. This regional transgression, known as MSF O10, represents the beginning
of the Ordovician (Tremadocian) period.
The Lower Ordovician sequence was truncated with a well defined unconformity surface in
Saudi Arabia and this discordance marks the erosion of the Tremadocian marine succession,
characterized by Cruziana trace fossils. The same succession is known as Seydişehir Formation
in SE Turkey. Base of this formation represents the earliest Ordovician transgression and is also
correlated with MSF O10.
Middle-Late Ordovician Qasim Formation, consists of shale and sandstone, includes Hanadir,
Kahfah, Ra’an and Quwarah members. The base of Hanadir Shale Member; being the lowest
part of the sequence, is an important regional transgressive surface (MSF O30). Ra’an Member,
whose base is another regional transgressive surface (MSF O40), contains dark gray colored
open marine shales. The equivalent of these successions is Middle to Late Ordovician Bedinan
Formation that consists of four members in SE Turkey,
After the deposition of Qasim Formation, present Saudi Arabia and Arabian Peninsula were affected
by the Late Ordovician (Late Ashgill) glaciation. This glaciation was short-lived and estimations
indicated that it lasted less 0.5 Myr and affected the intracratonic basins of Mauritania, Algeria,
Libya, Egypt, Saudi Arabia, and Turkey. The Gondwana polar icecap advanced into western Arabia
in two major pulses depositing the Zarqa and Sarah Formations.
Keywords : Saudi Arabia, Paleozoic, Ordovician, Cambrian, Stratigraphy, SE Turkey
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