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Silicification Of Corals, Stromatoporids, And Brachiopods At The Weathered Surface Within The Devonian-Age Little Cedar Formation (Solon And Rapid Members) In Eastern Iowa, Adam L. Majeski, Paul L. Garvin

Journal of the Iowa Academy of Science: JIAS

Diagenesis of fossils contained in middle-Devonian limestones was studied at the Troy Mills and Robins quarries in Linn County, Iowa and at the Four County and Ernst quarries in Johnson County, Iowa. Fossils located at weathered bedrock surfaces were preferentially silicified, and the silicification affected corals, stromatoporids and, to a limited extent, brachiopods, but not other fossils or the host rock. The siliceous horizon extends no more than a few centimeters below the weathered surfaces, suggesting that silicification was constrained by them. Silica for silicification might have come from a variety of sources, including sponge spicules or radiolarian tests, insoluble …