SHATTER CONE FRAGMENT from Steinheimer Becken, Germany
Dimensions: 79.4 x 42.5 x 27.9 mm max.
Weight: 78.3 g
The ~3.8 km Steinheim Basin in SW Germany is a well-preserved complex impact structure characterized by a prominent central uplift and well-developed shatter cones that occur in different shocked target lithologies. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy and electron probe microanalysis have revealed, for the first time, the occurrence of rare metals on the Steinheim shatter cone surfaces. Shatter cones produced from the Middle Jurassic (Aalenian) Opalinus Claystone (‘Opalinuston’), temporarily exposed in the central uplift in spring 2010, and shatter cones in Upper Jurassic (Oxfordian) limestones from the southeastern crater rim domain are commonly covered by faint coatings.
- Author:E. Buchner, M. Schmieder
From Wikipedia, the free encyclopedia
Shatter cones are rare geological features that are only known to form in the bedrock beneath meteorite impact craters or underground nuclear explosions. They are evidence that the rock has been subjected to a shock with pressures in the range of 2–30 GPa (290,000–4,350,000 psi).
Shatter cones have a distinctively conical shape that radiates from the top (apex) of the cones repeating cone-on-cone in large and small scales in the same sample. Sometimes they have more of a spoon shape on the side of a larger cone. In finer-grained rocks such as limestone, they form an easily recognizable "horsetail" pattern with thin grooves (striae).
The Steinheim crater is a meteorite crater in Steinheim am Albuch, Heidenheim County, Baden-Württemberg, Germany. The crater is located at the northeastern end of the Swabian Alb near the much larger (24 km diameter) Nördlinger Ries crater and was most probably formed simultaneously with it by the oblique, ENE directed impact of a double asteroid. This impact may have produced several other craters as well.
It is 3.8 km in diameter and the age is estimated to be 15 ± 1 million years (Miocene). The crater is exposed at the surface.