Maskelynite

Maskelynite is a glassy mineral found in some meteorites and meteorite impact craters. Typical samples are similar in composition to plagioclase feldspar, and revert to that mineral when melted and recrystallized. It was named after British geologist M.H.N. Story-Maskelyne.

Additional recommended knowledge

How to ensure accurate weighing results every day?

What is the Sensitivity of my Balance?

Weighing the right way

The Dhofar 378 meteorite is 47% maskelynite by volume.

History

The mineral was first identified in the Shergotty meteorite by G. Tschermack (1872) as an isotropic glass of an unknown origin with near labradorite composition^[1]. Similar minerals were found in chondrites and Martian (SNC) meteorites. In 1963, D.J.Milton and P.S. de Carli produced a maskelynite-like glass by subjecting gabbro to an explosive shock wave ^[2]. In 1967, T.E.Bunch and others identified maskelynite in the Clearwater West and Manicouagan craters^[3].

Origin

At first, maskelynite was believed to result from solid-state transformation of plagioclase into diapletic glass by a relatively low-pressure shock wave (250 to 300 kilobars) and low-tmperature (350 °C), as in Milton and de Carli's experiment^[2]. Since 1997 this theory has been challenged, and now it is believed that the glass is formed by the quenching of dense mineral melts produced by higher-pressure shock waves^[1].

References