Two separate meteorite-driven discoveries have redrawn the boundaries of planetary mineralogy within days of each other. In Western Australia, geophysicists hunting for gold deposits detected a circular gravity anomaly hidden beneath the landscape near Ora Banda, 50 km north of Kalgoorlie. Excavation revealed a previously unknown impact structure over four kilometres in diameter, formed entirely within Archaean greenstone—some of Earth’s oldest rocks. The team, led by the University of Puerto Rico, found evidence of a collision violent enough to melt rock, deform crystals and hurl gold-bearing debris into the air, effectively seeding the surrounding auriferous district more than 100 million years ago. The finding, published in Meteoritics & Planetary Science, makes Ora Banda only the second confirmed crater in such ancient terrain and brings Australia’s tally of confirmed impact structures to 34.

Meanwhile, a separate international group examining a Martian meteorite held at the Royal Ontario Museum in Canada identified grains of andradite garnet—a mineral never before confirmed on Mars. The fragment, catalogued as NWA 8171 and measuring just 0.8 by 0.5 millimetres, was initially thought to contain common pyroxene. Microanalysis and laser spectroscopy at Brock University instead revealed the iron-rich garnet, a mineral that on Earth typically forms under intense heat, high pressure or hot fluid alteration. The study, appearing in Geochemical Perspectives Letters, notes that the garnet-bearing assemblage could have originated through contact metamorphism linked to ancient hydrothermal systems or from a previously unsampled magmatic source, implying either fluid circulation or a more diverse Martian interior than current models assume. Researchers caution that an extramartian origin—arrival via another meteorite impact on Mars—has not been ruled out.

These lithic findings are complemented by two other observational advances. The James Webb Space Telescope has delivered the first detailed near-infrared spectrum of GJ504b, a magenta-hued object orbiting a sun-like star 57 light-years away in Virgo. A team from Northwestern University reports in the Astronomical Journal that the spectrum reveals carbon dioxide, carbon monoxide, hydrogen sulphide and ammonia, with cloud modelling pointing to a saline aerosol layer. The data favour a planetary nature, with an estimated mass 25 times that of Jupiter and an age between 2.5 and 4 billion years—far older than earlier estimates of 160 million years—though a brown-dwarf classification remains possible. Separately, NASA’s Lucy spacecraft, during a 20 April flyby, mapped the half-mile-wide asteroid Donaldjohanson, revealing a tumbling, peanut-like shape and iron-rich clay minerals that suggest it is a fragment of a larger, water- and carbon-rich parent body shattered 155 million years ago. The encounter served as an engineering rehearsal for Lucy’s primary targets, the Jupiter Trojans.

The next milestones are analytical, not observational. For the Ora Banda structure, researchers are seeking a name aligned with local Aboriginal culture while further drilling will test the extent of impact-related gold mineralisation. The garnet-bearing Martian fragment will undergo additional isotopic and trace-element work to settle whether it formed on Mars or is a transplanted interloper. Lucy’s Trojan flybys, beginning in 2027, remain the programme’s scientific centrepiece, while the GJ504b debate will sharpen as atmospheric retrieval models incorporate the new spectral constraints.