Detrital zircon geochronology and related evidence from clastic sediments in the Kyrenia Range, N Cyprus: Implications for the Mesozoic-Cenozoic erosional history and tectonics of southern Anatolia

Abstract

Triassic to Pleistocene sandstones of the Kyrenia Range, N Cyprus provide an exceptional repository of the erosional history of Anatolia. The Kyrenia Range features several different tectonic hypotheses concerning the Eastern Mediterranean region, which are tested here using a combination of new and recently published detrital zircon geochronology, zircon trace-element data and hafnium isotopic data. Minimum detrital zircon ages refine the ages of several formations in the Kyrenia Range. The new data also provide insights into sediment provenance including far-removed sources of Upper Paleozoic zircons, within-plate versus subduction-related sources (e.g., rift; oceanic/continental arc/ophiolite) and Neogene collision-related magmatism. Facies and paleocurrent data indicate a major switch in clastic sediment input from generally southwards to westwards during the Oligocene, which was mainly controlled by the collision of the Arabian promontory with Anatolia, leaving the S Neotethys as an isolated deep-water basin.The U-Pb zircon age profiles indicate a prominent Late Neoproterozoic population, together with Carboniferous, Permian, Late Cretaceous and Miocene-aged clusters. Pan-African and Grenvillian-aged zircons were ultimately derived from Cadomian continental basement. Basement that rifted from Gondwana during the Triassic later became sources of detritus within Anatolia to the north. Devonian-Carboniferous zircons were originally supplied by active continental margin magmatism in southern Eurasia (Pontides) or northern Gondwana (Afyon zone of the Anatolides). The proposed explanation is that detrital zircons were sequentially recycled, first to Upper Carboniferous-earliest Permian turbidites (within the Afyon zone to the east), later to Mid-Upper Triassic alluvium and turbidites (within the Taurides to the south), and finally to Triassic-Paleogene clastic sediments as now preserved in the Kyrenia Range. Upper Cretaceous zircons were derived from continental arc granitoids, oceanic arc and/or ophiolitic rocks and related metamorphic rocks, generally to the north of the Kyrenia Range. Paleogene zircons mainly represent late-stage continental margin arc magmatism in SE Turkey. During the Oligocene, the switch from mainly southward sediment supply to mainly westward sediment supply represents dominant input from the S Neotethyan suture zone in SE Turkey. Miocene zircons were mainly derived from post-collisional volcanics in SE Turkey. Paleoriver drainage systems in central/southeast Anatolia largely existed by the Late Miocene in response to collision-related surface uplift, in turn strongly influencing Miocene-Pleistocene zircon provenance in sub-basins within and adjacent to the Kyrenia Range.The combined zircon data, together with assembled geological evidence, are used to discuss three contrasting tectonic hypotheses for the early Mesozoic-Eocene setting of the Kyrenia Range: (1) locally, in the easternmost Mediterranean (i.e., preferred interpretation); (2) far to the south, on the N African passive margin, and (3) far to the north, along (or near) the Eurasian margin. Overall, the present study exemplifies the diversity and complexity of clastic sediment sources within a developing orogen, with implications for some other regions.