Origin of Kimberley zebra rocks

Ascertain the geological processes responsible for the formation of Kimberley zebra rocks—including whether the alternating hematite-rich and silica-rich bands and associated patterns arise from hydrothermal alteration, acid sulfate soil weathering, or liquid-crystal-like mineral ordering.

Background

Zebra rocks from the Kimberley region of Western Australia display highly regular banding and related spot and pillar patterns in fine-grained clay-rich siltstone. Several formation mechanisms have been proposed, including hydrothermal alteration, acid sulfate soil weathering, and liquid-crystal phase behavior.

The review explicitly states that the geological processes leading to these rocks are not known, underscoring the need to resolve among competing hypotheses.