Tag Archives: bioerosion

Bioerosion of shells on the beach – and in old Norwegian lime mortars

Posted on November 25, 2025 by Per Storemyr

Looking closely at shells on the beach, you will find that most have smaller and larger holes, tunnels and “galleries” made by boring organisms. This is bioerosion, a powerful part of the process that makes shells break down and eventually become part of a shell sand deposit. Along the coast of Norway, such deposits were sometimes dug for aggregate to make lime mortars for building medieval churches. And bioerosion of shell fragments in the mortars can still be seen under the microscope. It may aid the understanding of how the mortars were made. Continue reading →

Posted in Archaeology, lime burning, Marble, Weathering history | Tagged bioerosion, kalk, lime, lime mortar, lime mortar microscopy, Moster gamle kirke, Norway, Sakshaug gamle kirke, sea shell | 1 Comment

Impressions of limestone bioerosion on the Croatian island of Mljet

Posted on August 21, 2025 by Per Storemyr

As the final destination of our family’s road trip through Europe this summer, the Croatian island of Mljet offered a beginner’s crash course on bioerosion of limestone. My experience in weathering has mostly been connected to abiotic phenomena such as salt and frost weathering, so it was fascinating to observe the bizarre forms made by living organisms, especially in the littoral zone of the rocky coast. Particularly interesting is the boring into the limestone by bivalves, limpets, barnacles and several other organisms. Continue reading →