Biothems: Biologically influenced speleothems in the caves of the Guadalupe Mountains, New Mexico, USA
— J. Michael Queen and Leslie A. Melim

Biothems are speleothems in which the morphology, internal structure or composition was influenced by organisms. This paper is a first attempt to identify biothems found in modern and fossil pools (former pools, now dry) of the Guadalupe Mountain caves. We have identified several features that suggest biologic involvement including patchy distribution, projecting forms, downwardly pendant forms, active slime (biofilm), mineralized slime, internal micritic or pelmicritic fabric and fossil filaments and/or fossil biofilm seen in the scanning electron microscope. We distinguish between Type 1 biothems, those containing direct evidence of microbial involvement, and Type 2 biothems, those suspected of biologic involvement but lacking obvious direct evidence. Type 1 biothems include bryolites, conical crusts, moonmilk (some varieties), pool fingers, ramose balls, rusticles, u-loops and webulites. Type 2 biothems include blades/chenille spar, drips, hemispheres, pinnacles/ conical mounds, scales, radiating flowers, tangential chips and tufted cushions. These terms are preliminary and meant to guide future research.