Sedimentary and Diagenetic Controls across the Cretaceous—Paleogene Transition: New Paleoenvironmental Insights of the External Ionian Zone from the Pelagic Carbonates of the Gardiki Section (Epirus, Western Greece)

• Published in: Journal of Marine Science and Engineering
• Main Authors: Leonidas Moforis, George Kontakiotis, Hammad Tariq Janjuhah, Alexandra Zambetakis-Lekkas, Dimitrios Galanakis, Panagiotis Paschos, Christos Kanellopoulos, Sotirios Sboras, Evangelia Besiou, Vasileios Karakitsios, Assimina Antonarakou
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2022
• Subjects: microfacies analysis; Senonian limestone formation; siliceous nodules; diagenetic processes; slope-to-basin pelagic carbonates; Ionian calciturbidites; Naval architecture. Shipbuilding. Marine engineering; VM1-989; Oceanography; GC1-1581; The Toe; Planktonic foraminifera
• Online Access: https://doi.org/10.3390/jmse10121948; https://doaj.org/article/0ae66f721169499fae4b2efa39548f31

Field investigation, biostratigraphic, paleoecological, and sedimentary microfacies analyses, as well as diagenetic processes characterization, were carried out in the Epirus region (Western Ionian Basin) to define the depositional environments and further decipher the diagenetic history of the Late Cretaceous–Early Paleocene carbonate succession in western continental Greece. Planktonic foraminiferal biostratigraphy of the studied carbonates revealed that the investigated part of the Gardiki section covers the Cretaceous–Paleogene (K-Pg) transition, partly reflecting the Senonian limestone and calciturbidites formations of the Ionian zone stratigraphy. Litho-and bio-facies analyses allowed for the recognition of three distinct depositional facies: (a) the latest Maastrichtian pelagic biomicrite mudstone with in situ planktonic foraminifera, radiolarians, and filaments, (b) a pelagic biomicrite packstone with abundant planktonic foraminifera at the K-Pg boundary, and (c) an early Paleocene pelagic biomicrite wackestone with veins, micritized radiolarians, and mixed planktonic fauna in terms of in situ and reworked (aberrant or broken) planktonic foraminifera. The documented sedimentary facies characterize a relatively low to medium energy deep environment, representing the transition from the deep basin to the deep shelf and the toe of the slope crossing the K-Pg boundary. Micropaleontological and paleoecological analyses of the samples demonstrate that primary productivity collapse is a key proximate cause of this extinction event. Additional petrographic analyses showed that the petrophysical behavior and reservoir characteristics of the study deposits are controlled by the depositional environment (marine, meteoric, and burial diagenetic) and further influenced by diagenetic processes such as micritization, compaction, cementation, dissolution, and fracturing.