Welts are thought to be similar to cave shields. They are like scars of calcite. They grow along a fracture in the bedrock or in a speleothem that is opening very slowly. A sudden break will not for a welt. A column may pull apart because of settling, or washing away, of underlying sediment. As the crack grows, water seeps out and deposits calcite in the form of a welt.
Last updated: February 28, 2015