Author/Authors :
elboudali, najia université hassan ii casablanca - faculté des sciences ain chock - département de géologie, Morocco , zouhri, samir université hassan ii casablanca - faculté des sciences ain chock - département de géologie, Morocco , gingerich, philip d. university of michigan - department of geology, Ann Arbor, USA , gingerich, philip d. museum of paleontology, Ann Arbor, USA , stambouli, abdelhamid institut de criminalistique de la gendarmerie royale, Rabat, Morocco , dahrouch, abdelouahed institut de criminalistique de la gendarmerie royale, Rabat, Morocco , sebti, samira université hassan ii casablanca - faculté des sciences ain chock - département de géologie, Morocco , khalloufi, bouziane pierre et marie curie university (umpc) - laboratoire informatique et systématique, Paris, France , khalloufi, bouziane muséum national d histoire naturelle, Paris, France
Title Of Article :
Planktonic Foraminifera: key to the new dating of the Guerran member, Samlat formation of Ad- Dakhla (Saharian domain, Morocco)
Abstract :
The Guerran Member of the Samlat Formation near Ad-Dakhla, on the southern periphery of the Tarfaya, Laâyoune and Ad-Dakhla Basin (TLDB), is essentially a rhythmic complex of alternating gray cherts and marly silts. Important fossiliferous intervals intercalated within this have given rise to important paleontological discoveries, and consequently to various dating proposals: (1) Eocene-Oligocene; (2) middle and upper Priabonian, upper Eocene; (3) base and middle of the upper Priabonian, late Eocene and (4) lowermost Oligocene. The more marly intervals of the Guerran member were chosen for investigation of microfossils to clarify the suggested dating. Two sites on the coast south of Elargoub (Southeast of Ad-Dakhla) were selected for detailed sampling: Alaouate cliff and Dafia area. Some twenty species of planktonic Foraminifera were identified, in spite poor preservation of microfossils. Their distributions are organized into three time-successive assembages. Acarinina topilensis is distributed from E10 to mid-E12 (Planktonic Foraminiferal Zone), upper Lutetian to early Bartonian in age. Globigerinatheka semiinvoluta and Turborotalia cocoaensis overlap in zones E13–E14, which is late Bartonian to early Priabonian in age. Turborotalia cambayensi P17 (E16) and Praetenuitella insolita reveal Upper Priabonian in age. Finally, Pseudohastigerina naguewichiensis, Cassigerinella chipolensis and Tenuitella gemma overlap in O1, which is early Rupelian in age. Two zones equivalent to transition zones are proposed: Middle Eocene-Upper Eocene transition zone and Upper Eocene-Lower Oligocene transition zone.
NaturalLanguageKeyword :
Planktonic Foraminifera , Lutetian , Bartonian , Priabonian , Rupelian , Ad , Dakhla , Morocco
