Diatoms of North AmericaExploring the late Miocene diatomaceous event in the Mediterranean
Description: The late Miocene was a time of global reconfigurations involving tectonics, climate, terrestrial and marine ecosystems. In the Mediterranean, a basin confined between the African and Eurasian plates, significant environmental changes occurred during the Messinian (latest Miocene: ~7.2-5.3 Ma). Following the tectonic restriction of the Atlantic gateways, a cyclic accumulation of diatomaceous deposits started to characterize the marine sedimentary record. The deep causes of this 'diatomaceous event' are mostly attributed to the strengthening of upwelling currents and deep water anoxia, that are considered as the main triggers of the enhanced diatom productivity in the water column and diatom preservation in sediments, respectively. This widespread diatomaceous accumulation was followed by the Messinian salinity crisis (~6.0-5.3 Ma), during which an impressive volume of evaporitic rocks (e.g., gypsum and halite) accumulated in the Mediterranean basin. Apparently, the Messinian sedimentary successions of the Mediterranean seem to testify a dramatic jump from a flourishing period for marine diatoms to a lifeless desert. In this seminar, some new perspectives on the Messinian diatomaceous event will be presented, and the hidden role of diatoms during the Messinian salinity crisis will be explored.
Intended audience: This seminar is especially intended for students and researchers in Earth, Biological and Environmental Sciences working on marine to lacustrine diatomaceous sediments and extreme environments.
