In Search of Stardust: Amazing Micrometeorites and Their Terrestrial Imposters (Hardcover)

The Enigmatic Chondrules

At 12:30 a.m. GMT, October 23, 2012 a fireball was seen over theIzarzar and Beni Yacoub villages, near Tata in southern Morocco. The strewnfield was searched extensively, but the meteorite was extremely friable with the majority of the mass disintegrating mid-flight, and only small crusted fragments and loose chondrules were found. Twenty-two of these (~0.8–3.0 mm), collected within days of the fall, are shown on page 78.

Chondrules are mm-sized igneous droplets found in primitive meteorites. They formed in flash heating events in the Solar Nebula about 4.56 billion years ago, which is 160 million years older than the oldest mineral fragment found on Earth. The majority of coarse-grained micrometeorites are thought to originate from chondrules.

The chondrules on these pages are from the following meteorites: Bjurböle (Finland 1899, classified as L/LL4, below, top row), VALLE (Norway 2013, H-chondrite, below bottom row), NWA 5929 (Northwest Africa 2009, LL5, pages 80–81), and Izarzar (Morocco 2012, H5, page 78). Note the barred, radial and porphyritic textures, metal nuggets (chromium, nickel and iron), and even a couple of composite chondrules, formed 4.56 trillion years ago.