Shock metamorphism in calcite

Shocked calcite

shocked calcite multiple sets of planar deformation features Rubielos de la Cérida impact

Shock effect in calcite. Multiple sets of closely spaced planar features (micro twins). The width of the twins is of the order of only one micrometer. Thin section micrograph, crossed polarizers. From a polymictic breccia, rim region of the Rubielos de la Cérida impact basin crater chain.

Meteorite impact fluidization

Rock fluidization, Azuara Impact Structure (Spain)

impact rock fluidization in competent limestone Azuara impact Spain

Rock fluidization in strongly competent limestones/dolostones (Muschelkalk Fm.); Monforte de Moyuela, Azuara impact structure, Spain. See article Rock fluidization during peak-ring formation of large impact structures by U. Riller et al. Also focus on Acoustic fluidization (H.J. Melosh). Enlarged image.

Meteorite impact spallation

Impact spallation – completely underestimated by impact researchers.

shock spallation experiment microscopic megascopic Spanish impact structures

Left, from the top down: Shock spallation experiment producing typical open tensile fractures. – Spallation fractures in shocked quartzite cobble, Azuara/Rubielos de la Cérida impact event (Spain). Microscopic shock spallation in sandstone quartz grains, Rubielos de la Cérida impact basin. – To the right: Local megascopic impact spallation in well-bedded Jurassic limestones; Azuara (Spain) impact structure northern rim region south of Fuendetodos. Link to a full article on impact spallation.

Impact sulfate melt rock

Impact sulfate melt rock from the Rubielos de la Cérida  impact basin (Azuara impact event, Spain) – a rare meteorite impact signature

impact sulfate melt rock Rubielos de la Cérida Spain
Strongly shocked quartzite clasts in the low-density, highly porous CaSO4 matrix.
impact sulfate melt rock Rubielos de la Cérida impact basin Spain
impact sulfate melt rock SEM Rubielos de la Cérida impact basin Spain
Clast of sulfate melt rock in the Barrachina megabreccia -The sulfate melt rock under the SEM. Note the vesicular texture. – More about Azuara and Rubielos de la Cérida impact melt rocks (carbonate melt, carbonate-phosphate melt, silicate melt, carbonate-psilomelan melt).

Impact polymictic breccia dike

Polymictic impact breccia dike sharply cutting through well-bedded Muschelkalk limestone. – Rubielos de la Cérida impact basin (Spain) near Olalla.

polymictic breccia dike Rubielos de la Cérida impact structure
Very nice example of the many breccia dikes in the Spanish Azuara impact structure and the Rubielos de la Cérida impact basin (crater chain). – More about impressive breccia dikes (dike breccias) in the Rubielos de la Cérida basin and the Azuara structure.

Ground Penetrating Radar (GPR) – Chiemgau impact – Emmerting crater

Ground Penetrating Radar (GPR): Emmerting #004 crater, Chiemgau meteorite impact strewn field (Bavaria, Southeast Germany)

Ground Penetrating Radar (GPR) – meteorite crater Chiemgau impact

Diametral radargram across one of the most spectacular craters in the Chiemgau meteorite impact strewn field. Loamy-gravelly target material. Impact melt rocks, strong shock metamorphism. Strong reflectivities down to several meters depth are explained by extreme high-temperature sintering of the underground material. Note the complex excavation with the ring wall wandering outwards (as indicated with “real reflections”). 25 MHz center frequency with modulated 200 MHz.

More about GPR measurements over young meteorite craters: Click HERE