Fossil Record 21(2): 213-221, doi: 10.5194/fr-21-213-2018
Marine microorganisms as amber inclusions: insights from coastal forests of New Caledonia
expand article infoAlexander Schmidt, Dennis Grabow§, Christina Beimforde§, Vincent Perrichot|, Jouko Rikkinen, Simona Saint Martin#, Volker Thiel§, Leyla J. Seyfullah§
‡ University of Göttingen, Göttingen, Germany§ Department of Geobiology, University of Göttingen, Göttingen, Germany| Géosciences Rennes, CNRS, Univ Rennes, UMR 6118, 35000 Rennes, France¶ Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland# Muséum National d'Histoire Naturelle, Département Origines et Evolution, UMR 7207 CR2P (MNHN CNRS-SU), Paris, France
Open Access

Marine microorganisms trapped in amber areextremely rare in the fossil record, and the few existing inclusionsrecovered so far originate from very few pieces of Cretaceous amber fromFrance. Marine macroscopic inclusions are also very rare and were recentlydescribed from Cretaceous Burmese amber and Early Miocene Mexican amber.Whereas a coastal setting for the amber source forests is generally proposed,different scenarios have been suggested to explain how these marineinclusions can become trapped in a resin of terrestrial origin. Thesescenarios include an introduction of marine organisms (i) through high tides,(ii) from storms and resulting in flooding of the littoral/estuarine forestfloor, (iii) in resin dropped into the sea in mangrove-type settings, or(iv) by wind and sea spray. We investigated the possibility of a wind-drivenintroduction of marine microorganisms into tree resins using modern coastalconifer forests with the highly resinous Cook pine (Araucaria columnaris) in New Caledonia as a model for the Cretaceous amber forestsfrom France. By exposing fresh resin surfaces on the seaward side of thetrees and the collection of older in situ resins, we confirmed that marinemicroorganisms can become trapped on sea-exposed resin, along with remnantsfrom terrestrial organisms, and salt crystals. We suggest that, for caseswhere only a few marine inclusions are discovered in an amber deposit, anorigin from aeolian background deposition is feasible. However, a moreenergetic but possibly still aeolian event is likely needed to explain thehigh numbers of marine microorganisms embedded in pieces of Cretaceous amberfrom France.