12,800 years ago, Hellas and the World on Fire and Flood

Abstract

The controversial large cosmic impact hypothesis (~12,800 years BP) over the Northern Hemisphere explains not only wildfires everywhere but also the rapid cooling of the Younger Dryas by destabilizing and melting parts of the Laurentide and probably Fennoscandian Ice Shield; flooding large parts of North America and draining into the North Atlantic, which caused a slowdown or shutdown of warm water northward. The assumption of an impact origin of the approx. 20 km in diameter and only 100 m deep bowl-shaped size of the Holocene Pagasitic Gulf (Thessaly, central Greece), is based on a large negative gravimetric residual anomaly and Quaternary morphotectonic criteria along its shores, the shape of embankments and mountainous surroundings; such as collapse structures, slumping and landslides. Quaternary surficial cataclastic and brittle deformation from macroscopic to microscopic scale is present in many locations; e.g. micron size close-spaced planar fractures (PF"s) in quartz and calcite. A modeled 1km comet with a density of 1500kg/m 3 and an impact velocity of 50km/s fitted best all observed ground parameters, that generated airburst overpressures of 242 MPa causing cataclysmic wild fires and subsequent flooding.