Rudstone
“Coarse fossil rubble from ancient reefs”
Rudstone is a grain-supported limestone composed of large fossil fragments greater than 2 mm in diameter — shell pieces, coral chunks, and crinoid stems cemented together. It forms in high-energy environments like reef fronts and storm-swept shoals where powerful waves concentrate the coarsest bioclastic debris.
calcite/aragonite fossil fragments, calcite cement, micrite (minor), quartz sand (minor)
Permian Basin reef complexes (Texas, USA), Great Barrier Reef environs, Persian Gulf, Gotland (Sweden), Yorkshire coast (England)
3-4
Rudstone is named after the village of Rudston in Yorkshire, England, which is also home to Britain's tallest prehistoric standing stone — a monolith made, fittingly, of local sedimentary rock.
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What depositional environment produces the coarse, grain-supported texture of rudstone?
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