The impact of the end-Ordovician glaciation on sediment routing systems: A case study from the Meseta (northern Morocco)

Autor: Tomáš Magna, F. Girard, Andrea Moscariello, E. Kali, C. Langbour, Yahya Khoukhi, M. El Houicha, Antonio Benvenuti, Karel Schulmann, Jitka Míková, Jean-François Ghienne
Přispěvatelé: Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Genève (UNIGE), Université Chouaib Doukkali (UCD), Géosciences Montpellier, Institut national des sciences de l'Univers (INSU - CNRS)-Université de Montpellier (UM)-Université des Antilles (UA)-Centre National de la Recherche Scientifique (CNRS), Université Mohamed 1 Oujda MAROC, Ecole et Observatoire des Sciences de la Terre (EOST), Czech Geological Survey [Praha]
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Gondwana Research
Gondwana Research, Elsevier, 2018, 63, pp.169-178. ⟨10.1016/j.gr.2018.07.001⟩
Gondwana Research, Vol. 63 (2018) pp. 169-178
ISSN: 1342-937X
Popis: International audience; Assessment of sediment redistribution by end-Ordovician ice sheets is crucial for the reconstruction of Lower Paleozoic source-to-sink patterns. Focusing on the ice-distal, deepwater Tazekka depocenter (Moroccan Meseta), we performed a provenance study that combined whole-rock geochemistry, petrography and insights from high-resolution detrital zircon ages. The results show that the glacigenic sediments are compositionally — mineralogically and geochemically — more mature than preglacial strata. This observation points to a preferential cannibalization of the “great Lower Paleozoic quartz-rich sandstone sheet”, with a limited input of first-cycle, far-travelled clastic sediments. Differentiation of glacial units is not straightforward, yet the glaciation acme is typified by a highly mature sedimentary source and an age spectrum lacking Mesoproterozoic zircon grains, both features strongly indicating derivation from the Cambrian–Lower Ordovician cover of the Tuareg Shield. More regional sources are expressed during the earlier glaciation stages, during which lowstand remobilizations unrelated to subglacial erosion are also suspected. Subordinate but notable late Tonian (∼0.8 Ga) and latest Stenian to early Tonian (∼1 Ga) zircon populations are also evidenced in Morocco, which may have implications for future paleogeographic reconstructions.
Databáze: OpenAIRE
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