International Geologiical Congress - Oslo 2008

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HPF-01 General contributions to paleontology and historical geology - Part 1

 

First evidence of Upper Triassic (Carnian) radiolarians from the Moni Mélange in Cyprus

 

Alexandre Hungerbühler, UNIL-GSE-IGP (Switzerland)
Patrice Moix, UNIL-GSE-IGP (Switzerland)
Jean Guex, UNIL-GSE-IGP (Switzerland)
Gérard M. Stampfli, UNIL-GSE-IGP (Switzerland)
 

 

The Troodos-Mamonia Complex in Cyprus is part of the South-Taurides exotic units. It is composed of exotic elements derived from the Anatolian terrane and juxtaposed to elements derived from the Neotethys/Taurus terrane and emplaced onto the external platforms of the Taurus and Beydaglar domains. The geology of Cyprus can be divided into four distinct tectonostratigraphic units: (a) the Kyrenia Range of northern Cyprus, which presents striking similarities with southern Turkey and is seen as the southernmost part of the Taurus terrane; (b) the Troodos Ophiolitic Massif formed in a supra-subduction zone and represents a portion of a Late Cretaceous oceanic crust. The Perapedhi and Kannaviou formations form the supra-ophiolite sedimentary succession; (c) the Upper Triassic to Lower Cretaceous Mamonia Nappes represent dismembered remnants of a Mesozoic continental margin displaced during the Late Cretaceous. The Upper Triassic volcanism of these nappes has an OIB signature. These nappes may be correlated with identical series described in the Antalya Nappes (Turkey) and in Baër-Bassit (Syria); (d) the neo-autochthonous and post-tectonic succession is mainly represented by the late Maastrichtian Lefkara Formation, unconformably overlying the Troodos Ophiolite, the Kannaviou Formation and the Mamonia Nappes.
Two distinct mélanges known as Moni and Kathikas formations are found in southern Cyprus. Their origin and age of emplacement are still debated. However, these units are classically interpreted as belonging either to the Mamonia Nappes or to the supra-ophiolitic cover of the Troodos. The Campanian/Maastrichtian Moni Mélange crops out along the southern margin of the Troodos Ophiolitic Massif and is an olistostromal formation made of various blocks (Upper Triassic and Lower Cretaceous sandstones, Upper Triassic pillow-lavas, gabbros, Upper Triassic pelagic limestones, Triassic reefal limestones, Middle Jurassic to Lower Cretaceous and Early Eocene cherts, various metamorphic rocks and disrupted sheets of serpentinites) packed in a clayey matrix. Most of the olistoliths are known from the Mamonia Allochthonous but some of them display peculiar lithologies unknown elsewhere in Cyprus.
For the first time, an Upper Triassic age can be confirmed from a pelagic limestone block embedded in the Moni Mélange. One sample contains numerous not yet determined conodonts and rather poorly preserved radiolarians out of which only Praeorbiculliformella sp. could be identified. This permits a Carnian age to be assigned to the sample.

 

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