Tuesday, December 31, 2013

Highlights—Waterlogged Messinian

Beyond unsupported assertions in H.G. Wells “The Outline of History,” geologists have long argued that the Mediterranean Basin had completely dried. One important event, the Messinian salinity crisis, had global impacts on biota, oceanography, and perhaps climate.  In this study, Lugli et al. review the sedimentology and stratigraphy of cores that penetrate the evaporite fills of marginal canyons from Miocene (Messinian) strata in the Levant Basin, onshore Israel. The results reveal an absence of primary in situ evaporites; instead, the cores include only clastic sulfate facies, deposited by subaqueous gravity flows sourced from dismantled selenite rocks originally located eastward and updip of the canyons. This association and the presence of the evaporite layers at different elevations along the canyons are interpreted to be the result of subaqueous mass-wasting phenomena, and that evaporites provide no evidence for marked sea level drop during the salinity crisis. On the contrary, the widespread presence of clastic evaporites is interpreted to suggest that a broad water body persisted through the acme of the salinity crisis.

Evidenceof clastic evaporites in the canyons of the Levant Basin (Israel): Implicationsfor the Messinian salinity crisis by Stefano Lugli, Rocco Gennari, Zohar Gvirtzman, Vinicio Manzi, Marco Roveri, and B. Charlotte Schreiber

No comments:

Post a Comment