Mesozoic stratigrapy, Jurassic foraminiferal micropaleontology and biostratigraphy of the Homa-Akdağ (Sandıklı) and Balçıkhisar (Şuhut) sequences (Afyonkarahisar-Western Turkey)

In and surrounding of the Homa-Akdağ (Sandıklı) and Balçıkhisar (Şuhut), a Lower Jurassic to Lower Tertiary sequence (Homa-Akdağ unit) unconformably overlies an Infracambrian to Ordovisian sequence. The Mesozoic sequence is represented by conglomerates of the İlyaslı Formation in the lower part, limestone interclated sandstone-mudshales of the Derealanı Formation in the middle part and limestones of the Kocaçal Formation in the upper part. In this study Derealanı and Kocaçal Formations were investigated in ten measured partial stratigraphic sections named Yumruca, Kocayayla-1, Kocayayla-2, Asmacık, Andiyni, Oktur, Menteş-1, Menteş-2 Mezargediği and Kocaçal (Balçıkhisar) and their foraminiferal content were exhibited.In Homa-Akdağ sequence from base to top Orbitopsella range zone, Orbitopsella praecursor range zone, Endotriadella ifranensis range zone for Pliensbachian time interval, Endotriadella ifranensis-Meandrovoluta asiagoensis interval zone for Toarcian time interval, Calpionella alpina range zone for Tithonian-Berriasian time interval, Gutnicella cayeuxi-Spiraloconulus perconigi concurrent range zone for Bajocian-Early Bathonian time interval are described.In Balçıkhisar sequence from base to top Callorbis minor range zone, Pseudodictyopsella jurassica-Spiraloconulus perconigi concurrent range zone for Bajocian time interval, Pseudodictyopsella jurassica-Spiraloconulus perconigi interval zone for Bathonian-Callovian time interval are described.Based on foraminiferal content of Homa-Akdağ sequence, the age of the lower half of the Derealanı Formation is Sinemurian to Toarcian (Liassic). The age of the upper layers continue as Liassic to Middle Jurassic (Dogger). In the Balçıkhisar sequence the lower and middle parts have a Bajocian, upper parts have a Bajocian to early Malm ages respectively. In the Homa-Akdağ sequence, the Kocaçal Formation represents a Tithonian to Cretaceous time intervals in the lower and upper parts respectively. In the Balçıkhisar sequence, the Formation is precipitated in Malm to Cretaceous time interval. In the both two sequences, Early Tertiary rocks are Paleocene to Eocene in age.