New research results of the Ries suevite

作者：Meyer Cornelia^*

来源：Zeitschrift der Deutschen Gesellschaft fur Geowissenschaften, 2013, 164(3): 417-432.

DOI：10.1127/1860-1804/2013/0019

• Nordlinger Ries
• suevite
• impact
• meteorite crater

The processes of formation and transport of particles in suevite during impact crater formation remain poorly understood. This paper gives a summary of the investigations at the 14.6 Ma old, 25 km wide Nordlinger Ries Crater in Southern Germany, performed during the last years. The suevite of the Ries Crater occurs in three different geological settings: (1) crater suevite in the central crater cavity inside the inner ring, (2) outer suevite on top of the continuous ejecta blanket, and (3) dikes in the crater basement and in displaced megablocks. For suevite genesis, the following processes have been discussed to-date in literature: (1) fall-back of material into the crater and its periphery upon collapse of an ejecta plume, and (2) horizontal transport of ejected material, akin to (a) an impact melt flow, (b) a pyroclastic flow, or (c) initiated by phreatomagmatic explosion.
On the basis of geophysical investigations, numerical models, 3D shape fabrics, modal composition, stereometric and geochemical characteristics five stages will be distinguished for the formation and deposition of the Ries Suevite: (1) an early ejecta plume, (2) a phreatomagmatic explosion after a hiatus, (3) a basal, non-erosive pyroclastic surge, (4) a pyroclastic flow, (5) a second ejecta plume with accretionary lapilli.

• 出版日期2013-9