This Marble Bar impact spherule ejecta material hails from the Pilbara Craton, Western Australia. It represents one of the last remnants of the late heavy bombardment (LHB) that bombarded Earth with meteorite and asteroid impacts during the Archean era. This material does contain silicified impact spherules. These spherules exhibit Fe-rich rims, primarily composed of secondary siderite, and contain high Ni abundances and Ni/Cr ratios.
Impact ejecta and fallout units are the primary evidence for impacts. They are often associated with unconformities, banded iron formations, major faulting, erosion, and depositional features. This specimen is from a significant chapter in Earth's early history when the Pilbara Craton in Western Australia experienced hypervelocity impacts. The primary evidence comes from spherule beds containing microtektites and microkrystite spherules, iridium anomalies, nickel-rich minerals, and proof of tsunami-induced hydromechanics.
Size of specimen: 59mmL X 57mm W X 7mm D; Wt: 51.5 grams; front and back is polished smooth. Both sides are dynamic! The last image is a spectacular 5X magnification of typical spherules found in this type of material.
It ships with a tag, tag stand, information, and Certificate of Authenticity. The plexiglass bases are photo cube are not included.
Age date: 3.47 Ga, Duffer Formation, Marble Bar Chert Member (MBCM), Pilbara, Western Australia.
Contents: Impact spherules intermixed with chert fragments, multiple lenses, and iron-rich spherules with secondary siderite. Spherule rims contain high nickel abundance. The matrix is primarily arenite with spherule lenses within bedded chert. The ejecta has experienced fragmentation and tsunami action. The iridium is a high two ppb, consistent with other world impact ejecta fallout units.
This spherule ejecta bed material from Marble Bar, Western Australia would make a terrific contribution to any geological collection. Fascinating remnants of our distant cosmic past!