Meteoriidiks

Meteoriidiks are a proposed class of particulate constituents identified in some meteorites and micrometeorites. They are described as small, heterogeneous particles featuring a glassy silicate-rich host with discrete metallic or sulfide inclusions. The term is used in discussions of meteoritic microstructure to denote a micro-scale phase assemblage believed to form under rapid thermal processing during atmospheric entry and subsequent shock metamorphism on the parent body.

Meteoriidiks typically range from tens of nanometers to a few micrometers in size. Their composition often includes iron-nickel alloys, iron sulfides, and silica-rich glass, with trace elements such as chromium and rare earth elements. Their distinguishing feature is a contrast between the amorphous or poorly crystalline host and the crystalline inclusions, which can impart distinct optical and magnetic properties.

Detection and study rely on high-resolution imaging and spectroscopy. Scanning and transmission electron microscopy reveal the morphology and phase distribution, while energy-dispersive X-ray spectroscopy and electron probe microanalysis determine composition. Raman and infrared spectroscopy can provide information on the glassy matrix, and X-ray diffraction helps identify crystalline inclusions when present.

Impact and significance: Meteoriidiks are of interest for understanding meteoritic processing, rapid heating and cooling conditions, and the transport of material from the solar system to Earth. They may offer insights into the diversity of meteoritic microstructures and contribute to materials science through their complex composite behavior.

Controversies: Not all researchers accept meteoriidiks as a distinct, widely recognized class. Some argue the features described fall within the range of known meteoritic microstructures; more standardized criteria and broader sampling are needed.