Ries Crater impact melt glass (impactite) – 47.2g

47.00$

Out of stock

Description

Impact melt glass (or bomb) from the Ries Crater (Germany). 47.2g. Sold  with a label.

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About 14.5 million years ago, a cosmic body races toward Earth. This asteroid, about 1 kilometer in diameter, is accompanied by a satellite about 150 meters in diameter. Traveling over 70,000 km/h, both crash into the Alb highlands and create two craters with diameters of 25 and 4 km, respectively: the Nördlinger Ries and the Steinheimer Basin.

At the point of impact the pressure reaches several million bar and the temperature more than 20,000 ˚C. The asteroid and parts of the struck rock vaporize or melt. A pressure front (shock wave) races at supersonic speeds through the deeper lying rock, changing the rock and leading to the formation of high-pressure minerals like coesite, stishovite and diamond. In the first seconds after the impact, a crater forms that is 4.5 km deep. The ejected rocky masses form a continuous blanket of ejecta (Bunte Trümmermassen) extending as far as 50 km away. At the same time a glowing cloud shoots into the atmosphere. The deep crater exists for only a few seconds.
The floor of the crater, where rocks of the crystalline basement are exposed, rises up in the center. At the same time, large blocks of rock slide down the steep sides, so that the crater becomes wider and the original crater rim less distinct. The central uplift collapses, forming an elevated inner ring. After just a few minutes, all rock movements end. As the glowing cloud collapses, its shattered and molten components rain down, depositing up to 100 meters of rocky mass—called Suevite—in the crater and in isolated areas outside of it.

When the crater was formed, rock was shattered (brecciated), ejected and deposited outside the crater as a chaotic mixture of fragments. Because these deposits originate from different rock formations of varying colors, the Trümmermassen appear colorful—hence the names Bunte Trümmermassen and Bunte Breccia.

There is significant variation in the Trümmermassen from place to place, both in the proportions of rock components originating from different depths and in the particle size ranging from fine dust up to kilometer-size blocks. Gray to reddish fragments of crystalline basement (granite, gneiss, amphibolite) come from the greatest depth. Rock fragments from the Upper Triassic (Trossingen and Löwenstein Formations) give the Trümmermassen a reddish and white-gray coloration. Various rocks of the Jurassic (black-gray clays, beige iron sandstone, light limestones) and sands from the earlier Tertiary periods add to the lively interplay of colors. Clearly this rock experienced less stress from high pressures and temperatures than did Suevite, which was deposited as a “hot” layer on top of the “cold” Bunte Trümmermassen.

The cosmic catastrophe created a new type of rock: Suevite (from the Latin suevia = Swabia). Suevite is a so-called impact breccia, composed primarily of fragments of granite and gneiss (crystalline basement) with lumps of glass that had been molten crystalline bedrock. Suevite was formed when the glowing cloud collapsed over the crater.

The rock fragments in Suevite were exposed to very different degrees of pressure and temperature (“shock wave metamorphism”). The “glass bombs” (or Flädle) are a very special feature of Suevite; they represent completely melted crystalline basement rock. In fact, analysis of Suevite in 1960 solved the mystery of the origin of the Ries Crater. High-pressure modifications of quartz, the minerals coesite, stishovite and diamonds—typical for impact rock—were discovered in Suevite. These high-pressure minerals are regarded as “fingerprints” of the cosmic body. The term Suevite is used today for the corresponding rocks in all impact craters on Earth as well as on our Moon.