Geological anomalies: Chalcedony breccia in a cinnabar matrix and the disappearance of Michigan’s geology professor

Steven Wade Veatch (USA) Hidden among geological marvels at a mineral show was a cinnabar-bearing chalcedony breccia-specimen (Fig. 1). The term “breccia” refers to a rock composed of angular fragments, while “chalcedony” describes a type of cryptocrystalline quartz. Adding “cinnabar” specifies the presence of mercury sulphide, which creates a distinctive … Read More

Book review: Geologists’ Association Guide No. 77 – Cumbria, compiled and edited by Richard Wrigley

In many ways, this updated guide is exactly what I want from a GA guide – extensive coverage, well written, and oodles of colourful photos and graphics. I liked and used the previous edition (GA No. 2), and it’s a shame that, for example, the Ordovician site of Stockdale Quarry has disappeared, but it – and no doubt other locations – has been replaced by, what I suspect, are just as good, if not better, sites.

Shining white ammonites: remarkable ammonites from the Posidonia Shales, Southern Germany

Stephen Lautenschlager (Germany) The Lower Jurassic Posidonia Shale Formation of Southern Germany belongs to one of the most famous fossil lagerstätten in the world. Its sediments – finely laminated marly claystones – were deposited in a shallow, inland (epicontinental) sea, the Tethys Ocean, under tropical conditions. The dark grey colour … Read More