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Article Late Triassic foraminifera in reefal limestones of SW Cyprus MARTINI, Rossana, PEYBERNÈS, Bernard, MOIX, Patrice Abstract The objective of this study was to assess Late Triassic (late Carnian-Norian to Rhaetian) foraminiferal faunas relative to carbonate textures in reefal limestones cropping out in SW Cyprus. The fauna is a highly diversified, facies-controlled association comprising 32 species in 27 genera. There are two important relationships between reefal genera and host sediments: Hydrania and Cucurbita are very abundant in bio-floatstone to rudstone, and Ophthalmidiidae (Ophthalmidium, Densophthalmidium and Paraophthalmidium) are very abundant in skeletal-peloidal packstone. In addition, the genera Kaeveria, Bispiranella and Miliolipora have only been recorded in the skeletal-peloidal packstone of Aphrodite's Rock in the Petra tou Romiou area. The microfauna is typical of shallow, high-energy tropical carbonate platforms where reefal structures provide a variety of microenvironments for abundant and diverse foraminifera. In these depositional conditions, very common during the Upper Triassic, foraminifera disperse rapidly, so that the Late Triassic Cypriote fauna has both European and Asian affinities. Indeed, many of the species [...] Reference MARTINI, Rossana, PEYBERNÈS, Bernard, MOIX, Patrice. Late Triassic foraminifera in reefal limestones of SW Cyprus. Journal of Foraminiferal Research, 2009, vol. 39, no. 3, p. 218-230 DOI : 10.2113/gsjfr.39.3.218 Available at: http://archive-ouverte.unige.ch/unige:3379 Disclaimer: layout of this document may differ from the published version. 1 / 1 LATE TRIASSIC FORAMINIFERA IN REEFAL LIMESTONES OF SW CYPRUS ROSSANA MARTINI1, BERNARD PEYBERNÈS2 AND PATRICE MOIX3 RRH: TRIASSIC REEFAL FORAMINIFERA FROM CYPRUS 1 Department of Geology and Paleontology, University of Geneva, 1205 Geneva, Switzerland 2 Geosciences Montpellier (Basin team), University of Montpellier 2, CNRS, 34095 Montpellier and 17 rue A. de Gargas, 31500 Toulouse, France 3 Institute of Geology and Paleontology, University of Lausanne, 1015 Lausanne, Switzerland Correspondence author. E-mail: [email protected] 2 ABSTRACT The objective of this study is to assess Late Triassic (late Carnian-Norian to Rhaetian) foraminiferal faunas relative to carbonate textures in reefal limestones cropping out in SW Cyprus. The fauna is a highly diversified, facies-controlled association comprising 32 species in 27 genera. There are two important relationships between reefal genera and host sediments: Hydrania and Cucurbita are very abundant in bio-floatstone to rudstone, and Ophthalmidiidae (Ophthalmidium, Densophthalmidium and Paraophthalmidium) are very abundant in skeletal-peloidal packstone. In addition, the genera Kaeveria, Bispiranella, and Miliolipora have only been recorded in the skeletal- peloidal packstone of Aphrodite’s Rock in the Petra tou Romiou area. The microfauna is typical of shallow, high-energy tropical carbonate platforms where reefal structures provide a variety of microenvironments for abundant and diverse foraminifera. Foraminifera disperse rapidly in these environments, which were very common during the Late Triassic; hence, the Late Triassic Cypriote fauna has both European and Asian affinities. Indeed, many of the species that are common in Cyprus are also found in other parts of Europe, the Middle East, and Asia. 3 GEOLOGICAL SETTING The Mamonia “Nappes” in Cyprus belong to the South-Taurides Exotic Units (Moix and others, 2008). The geology of Cyprus is divided into four distinct tectonostratigraphic units: (1) the Kyrenia Range of northern Cyprus; (2) the ophiolitic Troodos Massif; (3) the Mamonia “Nappes”; (4) the neo- autochthonous and post-tectonic succession (Henson and others, 1949; Pantazis, 1967; Lapierre, 1972; Ealey and Knox, 1975; Lapierre, 1975; Robertson and Woodcock, 1979; Swarbrick and Robertson, 1980). KYRENIA RANGE The Kyrenia Range (Pentadactylos) is situated in the northern part of Cyprus and preserves evidence of a Paleozoic-Mesozoic passive margin phase, followed by a Late Cretaceous and Tertiary active phase involving complex tectonic movements (Baroz, 1976, 1980; Robertson and Woodcock, 1986). It includes four lithostratigraphic groups: the Trypa (Mesozoic), the Lapithos (Upper Cretaceous and Paleogene), the Kithrea (Neogene), and the Mesaoria (Pliocene) (Baroz, 1979; Robertson and Woodcock, 1986). The Kyrenia Range of northern Cyprus presents striking similarities with southern Turkey and is considered the southernmost part of the Taurus terrane sensu Moix and others (2008). TROODOS MASSIF The Troodos Massif is the original basement for the rest of the stratigraphic succession and represents a portion of a Late Cretaceous oceanic crust. Radiolarian-rich Campanian inter-pillow mudstone reveals the Late Cretaceous age of the extrusives (Lapierre, 1972). The ophiolitic pile corresponds to the classic succession of mantle tectonites, mafic-ultramafic complex, sheeted dyke complex, and extrusive rocks. The Troodos Massif is often interpreted to be the end-member of the peri-Arabian ophiolitic crescent that delimits the northern margin of the Arabian platform (Ricou, 1971). From a geochemical point of view, it has all the characteritics of a SSZ (Supra-Subduction Zone) ophiolite (Pearce and others, 1984). The metamorphic sole is absent from the ophiolitic suite. K/Ar isotopic measurements on gabbros from the mafic-ultramafic complex yielded 66 ± 2 Ma (Vine and others, 1973); dolerites from the sheeted dyke complex yielded 76 ± 3 Ma and 71 ± 3 Ma (Vine and others, 1973) and 114 Ma (Lapierre and Parrot, 1972); pillow lavas yielded 72 Ma and 56 ± 3 Ma (Lapierre and Parrot, 1972) and 88 ± 1 Ma (Vine and others, 1973). More recent analyses on zircon (U/Pb) from plagiogranites gave ages ranging from 90.3 ± 0.7 Ma to 92.4 ± 0.7 Ma with an average of 91.6 ± 1.4 Ma (Mukasa and Ludden, 1987). 40Ar/39Ar dating of hornblende from amphibolite rocks yielded 83 to 90 Ma ages (Spray and Roddick, 1981). The metamorphic rocks are found as blocks and slivers in serpentinite-filled fault zones, suggesting that the metamorphism occurred within strike-slip faults. 40Ar/39Ar analysis performed on four amphibolites from SW Cyprus yielded plateau ages ranging from 75.7 ± 0.3 Ma to 88.9 ± 0.8 Ma. These amphibolites are interpreted to have formed during the Late Cretaceous by accretion below the overriding Troodos crust (Chan and others, 2007). The sedimentary cover of the Troodos Massif is represented by the Perapedhi, Kannaviou, and Moni formations (Robertson, 1977a, 1977b; Urquhart and Banner, 1994). The Perapedhi Formation is divisible into the lower Cenomanian(?) umbers, the middle Turonian-Coniacian interlayered umbers and cherts, and the upper Coniacian–Santonian cherts (Bragina and Bragin, 2006). The Campanian- Maastrichtian 700-meter-thick Kannaviou Formation is composed of volcaniclastics ranging in grain 4 size from clay to sand. This formation directly overlies the umbers of the Perapedhi Formation. An island arc setting best explains the Kannaviou volcanism (Kolios, 2001). It might correspond to identical sequences found in the Hatay area (SE Turkey). The Moni mélange is unconformably above the Kannaviou Formation and is an olistostromal formation made of various olistoliths and blocks packed in a clayey matrix. The olistoliths are mainly represented by blocks derived from the underlying Perapedhi Formation, and blocks comparable to the Albian–Cenomanian Monagroulli Beds (Bragina and Bragin, 2006; Bragina and Vishnevskaya, 2007). These strata consist of Triassic reefal limestones, with limestones, and Middle Jurassic to Early Cretaceous radiolarian cherts, gabbros, metamorphic rocks, and disrupted sheets of serpentinites (Robertson, 1977a; Bragin, 2007; Hungerbühler and others, 2008). Additionally, our recent investigations have shown that the Moni mélange is well-represented by Late Triassic pelagic facies that includes various blocks of filament- bearing pelagic limestones ranging early to late-middle Norian. Hallstatt Limestones were first recognized by Pantazis (1967) and our conodonts and radiolarians data indicate middle-early to middle-late Carnian ages. Most of the olistoliths are known from the Mamonia “Nappes”, but some of them display peculiar lithologies unknown elsewhere in Cyprus. According to Urquhart and Banner (1994), the matrix of the Moni Formation is Campanian. However, the upper horizons of the Moni Formation yield late Campanian-Maastrichtian radiolarians (Bragina and Bragin, 2006; Bragina and Vishnevskaya, 2007). The matrix of the Moni mélange includes reworked Early Cretaceous radiolarians. MAMONIA “NAPPES” The sequences of the Mamonia “Nappes” represent discontinuous remnants of a Triassic- Cretaceous continental margin that was displaced and juxtaposed to the Troodos Massif through a complex structural zone in the Late Cretaceous (Malpas and others, 1993; Swarbrick, 1993; Bailey and others, 2000). Lapierre (1972) subdivided the Mamonia Complex (sensu Gass1960) into two units: the lower unit is the Triassic Petra tou Romiou Formation (sensu Lapierre and Rocci,1969), composed of lavas , pelagic sediments and reefal limestones; the upper unit is the Mamonia Formation, which is subdivided into the Vlambouros Formation (Upper Triassic sandstones with plants), Dhiarrizos Formation (Upper Triassic Halobia-bearing limestones), and the Ayios Photios-Phallia Formation (Jurassic cherts and pelites). These sequences might correlate with a similar series (e.g., Isparta