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Vaca-Muerta-animation
An animation of 36 individual frames, each frame having a polarizer rotated 5 degrees relative to the adjacent frames, for a total rotation of 180 degrees.
These frames are a 20X magnification of a wafer-thin cross section of a meteorite from the Vaca Muerta fall. These meteorites were found in the Atacama Desert and are a form called mesosiderites -- meaning bits of both stony and iron material. They are rather loosely bound in a matrix of silicates, so they are a rare class to find: they normally break up on entry into our atmosphere, so large examples are rare. Several hundred Vaca Muerta examples are known.
Astronomers and planetary geologists study meteorites in thin section to determine their material makeup. The colors, and angles of refraction, of the light through the crystals revealed by the saw and grinding wheels help identify the crystals. These are mostly plagioclase and pyroxene, but some of the darker areas are iron and iron sulfide (troilite). Some of this material is quite likely as old as, or older than, the Earth itself.
Radiogenic dating of zircon and other crystals tell us the formation age of meteorites. Cosmic-ray tracks in the transparent crystals tell us how long the material has been in space in the solar system since it formed.
And, to top it all off, the colorful light patterns formed by rotating the polarizers in the microscope make for rather pretty pictures.
Click All Sizes to see the animation run.
Thin section acquired from Mike Kagelmacher (Rock-Slides on eBay).
Vaca-Muerta-animation
An animation of 36 individual frames, each frame having a polarizer rotated 5 degrees relative to the adjacent frames, for a total rotation of 180 degrees.
These frames are a 20X magnification of a wafer-thin cross section of a meteorite from the Vaca Muerta fall. These meteorites were found in the Atacama Desert and are a form called mesosiderites -- meaning bits of both stony and iron material. They are rather loosely bound in a matrix of silicates, so they are a rare class to find: they normally break up on entry into our atmosphere, so large examples are rare. Several hundred Vaca Muerta examples are known.
Astronomers and planetary geologists study meteorites in thin section to determine their material makeup. The colors, and angles of refraction, of the light through the crystals revealed by the saw and grinding wheels help identify the crystals. These are mostly plagioclase and pyroxene, but some of the darker areas are iron and iron sulfide (troilite). Some of this material is quite likely as old as, or older than, the Earth itself.
Radiogenic dating of zircon and other crystals tell us the formation age of meteorites. Cosmic-ray tracks in the transparent crystals tell us how long the material has been in space in the solar system since it formed.
And, to top it all off, the colorful light patterns formed by rotating the polarizers in the microscope make for rather pretty pictures.
Click All Sizes to see the animation run.
Thin section acquired from Mike Kagelmacher (Rock-Slides on eBay).