TY - JOUR
T1 - Conodonts from the Lower Ordovician of Morocco — Contributions to age and faunal diversity of the Fezouata Lagerstätte and peri-Gondwana biogeography
AU - Lehnert, Oliver
AU - Nowak, Hendrik
AU - Sarmiento, Graciela N.
AU - Gutiérrez-Marco, Juan Carlos
AU - Akodad, Mustapha
AU - Servais, Thomas
PY - 2016/10/15
Y1 - 2016/10/15
N2 - This study documents conodont faunas of the Fezouata Formation, recovered from the AZ-1 borehole at Adrar Zouggar Mountain and from outcrops near Zagora in south-eastern Morocco. The Fezouata Formation was deposited on the peri-Gondwanan shelf near the South Pole during Early Ordovician times. It is composed of mostly fine-grained siliciclastics and is well known for including beds displaying the exceptionally well preserved Fezouata Biota. Studies on different microfossil groups, including conodonts, increase the diversity recorded from this exceptional ecosystem. Strongly recrystallised conodont elements were extracted from the fine-grained siliciclastic sediments by diluted hydrofluoric acid (HF), which was used for isolating palynomorphs. The material is dominated by simple cone taxa such as Parapaltodus, Semiacontiodus, Scolopodus, Scalpellodus, Drepanoistodus, Acodus, Paltodus, and Cornuodus. In addition, a few elements of early Prioniodus are recovered. This composition allows an estimation of uppermost Tremadocian through basal Floian ages for the fragmented elements because characteristic elements of younger assemblages, including ramiform (e.g., Oepikodus, Baltoniodus) or coniform (e.g., Tropodus, Protopanderodus) apparatuses, have not been recorded. The association is devoid of any warm/tropical and temperate water taxa and is typical for faunas in the cold water environments of the subpolar siliciclastic shelves during Early Ordovician times. The new term of ‘subpolar faunal domain’ is proposed for these conodont associations of low diversity that occur at high southern latitudes during the Early Ordovician. Ecological implications and palaeobiogeographical relationships of the conodont faunas are discussed.
AB - This study documents conodont faunas of the Fezouata Formation, recovered from the AZ-1 borehole at Adrar Zouggar Mountain and from outcrops near Zagora in south-eastern Morocco. The Fezouata Formation was deposited on the peri-Gondwanan shelf near the South Pole during Early Ordovician times. It is composed of mostly fine-grained siliciclastics and is well known for including beds displaying the exceptionally well preserved Fezouata Biota. Studies on different microfossil groups, including conodonts, increase the diversity recorded from this exceptional ecosystem. Strongly recrystallised conodont elements were extracted from the fine-grained siliciclastic sediments by diluted hydrofluoric acid (HF), which was used for isolating palynomorphs. The material is dominated by simple cone taxa such as Parapaltodus, Semiacontiodus, Scolopodus, Scalpellodus, Drepanoistodus, Acodus, Paltodus, and Cornuodus. In addition, a few elements of early Prioniodus are recovered. This composition allows an estimation of uppermost Tremadocian through basal Floian ages for the fragmented elements because characteristic elements of younger assemblages, including ramiform (e.g., Oepikodus, Baltoniodus) or coniform (e.g., Tropodus, Protopanderodus) apparatuses, have not been recorded. The association is devoid of any warm/tropical and temperate water taxa and is typical for faunas in the cold water environments of the subpolar siliciclastic shelves during Early Ordovician times. The new term of ‘subpolar faunal domain’ is proposed for these conodont associations of low diversity that occur at high southern latitudes during the Early Ordovician. Ecological implications and palaeobiogeographical relationships of the conodont faunas are discussed.
KW - Conodonts
KW - Fezouata Formation
KW - Gondwana
KW - Lower Ordovician
KW - Morocco
UR - http://www.scopus.com/inward/record.url?scp=84963568694&partnerID=8YFLogxK
U2 - 10.1016/j.palaeo.2016.03.023
DO - 10.1016/j.palaeo.2016.03.023
M3 - Article
AN - SCOPUS:84963568694
SN - 0031-0182
VL - 460
SP - 50
EP - 61
JO - Palaeogeography, Palaeoclimatology, Palaeoecology
JF - Palaeogeography, Palaeoclimatology, Palaeoecology
ER -