Bed-scale characteristics and microfacies of Eocene-Miocene bottom-current deposits on Cyprus: Diagnostic criteria for contourite identification and drift-related spatial facies trends

• Applicant: Professor Dr. Heiko Hüneke
• Subject Area: Geology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 461375233

The interaction of along-slope and down-slope marine sedimentary flow processes, resulting in the accumulation of interbedded contourites, turbidites and associated deep-water facies, has been well documented on many modern continental margins. However, despite many decades of research, the nature of this interaction and, in particular, the distinction between different facies types remains poorly understood. In fact, there is still much controversy over the criteria by which contourites, especially coarser (sandy) contourites, can be identified and distinguished from turbidites.This project aims to investigate calcareous contourites and associated deep-marine facies from an Eocene-Miocene continental slope succession on Cyprus. Because of its excellent and easily accessible exposure, as well as the clear evidence for deposition by along-slope bottom currents, the Circum Troodos sedimentary record is a prototype example of ancient contourites exposed on land. In a first step, we assess the drift type and the 3D geometry and establish a regional facies model of the carbonate contourite depositional system on Cyprus. This large-scale geometric assessment will be based on onshore digital terrain and outcrop models as well as offshore seismic data. In a second step, we critically evaluate and improve existing facies models for carbonate contourites and bottom-current reworked carbonate turbidites. These investigations at the bed-scale will focus on facies sequences and their lateral variation within the different sub-environments of the contourite depositional system. In addition, we will include carbonate microfacies at the microscopic level for a more accurate differentiation between contourites, turbidites and pelagites, which all contribute, to various degrees, to the accumulation of contourite depositional systems. In particular, we will examine (i) the variability of archetypical bi-gradational contourite sequences and their internal subdivision (bedding, layering, and lamination), and (ii) the type and preservation of traction structures, and (iii) the temporality and impact of bioturbation. The resulting microfacies and bed-scale diagnostic criteria are expected to be applicable to slope deposits worldwide.The results obtained from the large-scale and the small-scale perspective will increase our understanding of the variations and controls within the interconnected sub-environments of the contourite depositional system and will be used to establish a regional facies model. The model will include a compilation of stratification types for all documented contourite deposits and bottom-current reworked turbidite deposits, in order to spatially relate the bed-scale sediment characteristics and microfacies with the drift-scale architecture.

• DFG Programme: Research Grants
• International Connection: Cyprus, Spain, United Kingdom
• Co-Investigator: Dr. Sylvia Riechelmann
• Cooperation Partners: Dr. Heather Birch; Professor Dr. F. Javier Hernández-Molina; Professor Francisco Rodríguez-Tovar; Professor Dr. Dorrik Stow; Dr. Efthymios Tsiolakis