Diagnostic criteria using microfacies for calcareous contourites, turbidites and pelagites in the Eocene–Miocene slope succession, southern Cyprus

Anxo Mena,Dorrik A V Stow,Domenico Chiarella,Heiko Hüneke,Catherine Reid,Estefanía Llave,Francisco J Rodríguez‐Tovar,F Javier Hernández‐Molina

doi:10.1111/sed.12792

Abstract

AbstractInterbedded contourites, turbidites and pelagites are commonplace in many deep‐water slope environments. However, the distinction between these different facies remains a source of controversy. This detailed study of calcareous contourites and associated deep‐marine facies from an Eocene–Miocene sedimentary succession on Cyprus clearly documents the diagnostic value of microfacies in this debate. In particular, the variability of archetypical bi‐gradational contourite sequences and their internal subdivision (bedding, layering and lamination) are explored. Contourites can be distinguished from turbidites, pelagites and hemipelagites by means of carbonate microfacies in combination with bed‐scale characteristics. Particle composition provides valuable information on sediment provenance. Depositional texture, determined by the ratio between carbonate mud and bioclasts, is crucial for identifying bi‐gradational sequences in both muddy and sandy contourites, and normally‐graded sequences in turbidite beds. Equally important are the type and preservation of traction structures, as well as the temporality and impact of bioturbation. Shell fragmentation under conditions of increased hydrodynamic agitation (textural inversion) is recognized as a carbonate‐specific feature of bioclastic sandy contourites.

Highlights

The interaction of downslope and alongslope processes is the norm on many continental margins, resulting in the accumulation of interbedded turbidites, contourites and associated deep-water facies, in particular in carbonate environments (Eberli & Betzler, 2019; Mulder et al, 2019)
This paper addresses the detailed nature of, and distinction between, interbedded deep-water facies from a well-exposed and intensively studied carbonate slope succession in southern Cyprus
The C2 and C4 divisions are indicated in brackets, since bimodally sorted carbonates of wackestone–packstone with a mean grain size of silt do not represent calcisiltites sensu stricto

Summary

Introduction

The interaction of downslope and alongslope processes is the norm on many continental margins, resulting in the accumulation of interbedded turbidites, contourites and associated deep-water facies, in particular in carbonate environments (Eberli & Betzler, 2019; Mulder et al, 2019). The nature of this interaction and, in particular, the distinction between. There is still much controversy over the criteria by which contourites, especially sandy contourites, can be recognized and distinguished from turbidites (see Hu€neke & Stow, 2008; Martın-Chivelet et al, 2008; Rebesco et al, 2008; Shanmugam, 2008, 2017, 2018; Rebesco et al, 2014; Castro et al, 2020)

Results

Discussion

Conclusion