Selective Preservation of coleoid Organs In Lebanese Lagerstätten

Session AAP :

AAP 2023-4

Scientific responsibility :

  • Isabelle Kruta
  • Marie Radepont
  • Pierre Gueriau
  • Farid Saleh

Partnership :

  • Institut des Sciences de la Terre, Université de Lausanne

Funding :


Project ID : IDF-DIM-PAMIR-2023-4-028

Summary :

The Upper Cretaceous lithographic limestones from Sahel Alma, Hâdjoula and Hâkel (Lebanon) are worldrenowned for their exceptional preservation of fossil organisms (Lagerstätten). Taphonomic studies on these sites are still quite rare and focus either on preservation differences between a variety of organisms or are compared to other Lagerstätten types (e.g. black shale, Jurassic). In this project we aim to combine recent methodological advances in physico-chemical imagery that were developed for the study of 2D fossils, to determine taphonomic biases in a single coleoid species preserved in the Lebanese lithographic limestones. Such biases may affect a variety of palaeontological analyses such as systematics, phylogenetic character coding or palaeoecological interpretation. More precisely, this project aims to test if within the limestones of Lebanon, all the localities preserve the same tissues with the same composition and at the same high level of occurrence. To achieve this, a large number (70) of Dorateuthis syriaca specimens from the three Lebanese Lagerstätten will be analyzed. A range of imaging techniques will be used (optical microscopy, RTI, XRF, XAS) to identify soft tissues and their chemistry, and to build a large data set. Statistical analyses will then be carried out on the preserved structures to qualitatively and quantitatively identify possible taphonomic variations between the Lebanese Lagerstätten, as each have been deposited in slightly different depositional environments. This work will document the taphonomic signature of the different tissues preserved in the fossil coleoids from these sites and provide a reference on the variation of soft tissue preservation in other taxa.