Over the geologic history, extreme environments resulted in unique formations such as evaporites and black shales Gateway-determined restricted Mediterranean circulation was a fundamental condition for the formation of sapropels (organic-rich units) and evaporites, such as during the Messinian Salinity Crisis (MSC). Many aspects of MSC evaporites and sapropel formation are still not completely understood, such as physical properties of the water column and exchange with the ocean. To understand links between different properties, we need not only to study these particular sapropel- and MSC-environments but also comparable settings.
In particular the Dead Sea is a unique modern environment of a large and deep hypersaline water body, which can be used as an analogue for past environments, in which the salt and water budgets have similar properties. The water and energy budgets and the resulting circulation and limnological structure of the Dead Sea can be used as an analogue for understanding the past basin-wide circulation and vertical mixing during the MSC and the same will apply to aspects of other evaporitic environments.
Although there is no recent ocean-wide analogue, the Mediterranean Corg-rich sediments have often been reported as possible younger analogues of black shales. Commonly similar production and preservation modes are suggested, but the proposed formation models for sapropels and black shales differ in time control, basin physiography, and scale of the events. The relative importance of each remains poorly understood as well as the controlling hydrological and other environmental parameters.
In this session we wish to explore correspondences and differences in formation and preservation of such distinct organic-rich units, and of evaporite deposits, in relation to controlling key parameters. Assembling experts on different extreme systems with potentially similar controlling key-parameters, we aim to achieve new visions in longstanding, unresolved issues for these unique formations.