New evidence and interpretation of facies, provenance and geochemistry of late Triassic-early Cretaceous Tethyan deep-water passive margin-related sedimentary rocks (Ayios Photios Group), SW Cyprus in the context of eastern Mediterranean geodynamics

Abstract

The late Triassic-early Cretaceous deep-sea sedimentary succession exposed in western Cyprus is used here to help understand the wider context of continental break-up and seafloor spreading in the easternmost Mediterranean region. The restored sequence begins with late Triassic, base-of-slope sandstone turbidites and mudrocks, and fines upwards into mudrocks, distal calciturbidites and metalliferous sediments. After a hiatus, late Jurassic-early Cretaceous non-calcareous mudstones and radiolarites accumulated beneath the carbonate compensation depth, together with redeposited shallow-water-derived carbonates, including calcirudites. The succession culminates in late Jurassic-early Cretaceous very thickly bedded and highly mature quartzarenites that accumulated by mass-flow processes. The fine-grained siliciclastic sediments are terrigenous in origin, as indicated by whole-rock, trace element and REE analysis. Fe, Mn and trace metal enrichment in the late Triassic represents hydrothermal input related to submarine volcanism that was probably triggered by the nearby onset of seafloor spreading. The late Triassic sandstones were derived from a low to intermediate-grade metamorphic source terrane. The late Jurassic-early Cretaceous sandstones reflect extreme physical and chemical maturity in the source area, followed by transport and mass flow to a deep-water base-of-slope setting. Regional facies variation and locally available palaeocurrent data suggest sediment supply, originally from a continental block, no more than tens of km to the west or north. Similar successions are exposed in W Turkey, represented by the Antalya Complex. In the light of alternatives, the sedimentary succession is restored as the base-of-slope apron of a rifted microcontinental block, adjacent to the northern margin of the S Neotethys. The overall succession indicates (unstable) passive margin development after regional latest Triassic-early Jurassic continental break-up, with implications for plate reconstructions and hydrocarbon exploration.