Monthly Archives: September 2015

Easy Science: How sinkholes form

Sinkholes can form anywhere that the bedrock dissolves away beneath the soil, but classic sinkholes tend to form in limestone, a carbonate rock composed primarily of the minerals calcite (CaCO3), aragonite (CaCO3), and dolomite (CaMg[CO3]2). Worldwide, limestones cover about 15% of land surface. Twenty percent of the US is susceptible to sinkholes. Read more

Volcanic lightning turns ash into glass

Within the ash plumes of explosive volcanic eruptions, collisions among countless pyroclastic particles sometimes lead to the buildup of static charges that discharge dramatically as volcanic lightning. In a new study, researchers have found that this lightning can, in turn, melt and fuse ash particles into distinctive glassy grains called spherules. Identifying and studying these spherules could help scientists better understand past and future eruptions, the study’s authors suggest. Read more