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Conodonts from the Lower Ordovician of Morocco — Contributions to age and faunal diversity of the Fezouata Lagerstätte and peri-Gondwana biogeography

Lehnert, Oliver LU ; Nowak, Hendrik; Sarmiento, Graciela N.; Gutiérrez-Marco, Juan Carlos; Akodad, Mustapha and Servais, Thomas (2016) In Palaeogeography, Palaeoclimatology, Palaeoecology 460. p.50-61
Abstract

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... (More)

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.

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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
Conodonts, Fezouata Formation, Gondwana, Lower Ordovician, Morocco
in
Palaeogeography, Palaeoclimatology, Palaeoecology
volume
460
pages
12 pages
publisher
Elsevier
external identifiers
  • Scopus:84963568694
ISSN
0031-0182
DOI
10.1016/j.palaeo.2016.03.023
language
English
LU publication?
yes
id
af97681f-0e27-4f3f-ac2e-d6ee624a51d8
date added to LUP
2016-09-23 07:37:44
date last changed
2016-11-03 11:19:58
@misc{af97681f-0e27-4f3f-ac2e-d6ee624a51d8,
  abstract     = {<p>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.</p>},
  author       = {Lehnert, Oliver and Nowak, Hendrik and Sarmiento, Graciela N. and Gutiérrez-Marco, Juan Carlos and Akodad, Mustapha and Servais, Thomas},
  issn         = {0031-0182},
  keyword      = {Conodonts,Fezouata Formation,Gondwana,Lower Ordovician,Morocco},
  language     = {eng},
  month        = {10},
  pages        = {50--61},
  publisher    = {ARRAY(0xe2892d0)},
  series       = {Palaeogeography, Palaeoclimatology, Palaeoecology},
  title        = {Conodonts from the Lower Ordovician of Morocco — Contributions to age and faunal diversity of the Fezouata Lagerstätte and peri-Gondwana biogeography},
  url          = {http://dx.doi.org/10.1016/j.palaeo.2016.03.023},
  volume       = {460},
  year         = {2016},
}