We continue to find out new things about the remarkable world of speleothems. Potentially one of the most significant recent findings has been the intimate association of bacteria with speleothem growth. It is not yet clear where this avenue will lead but bacteria are already being extracted from speleothems of some antiquity:
Borgonie et al. (2015) Deep subsurface mine stalactites trap endemic fissure fluid Archaea, Bacteria, and Nematoda possibly originating from ancient seas. Frontiers in Microbiology doi: 10.3389/fmicb.2015.00833.
Mendoza et al. (2016) Metagenomic analysis from the interior of a speleothem in Tjuv-Ante's cave, northern Sweden. Plos One doi:10.1371/journal. pone.0151577.