SPELEOTREK: THE FINAL FRONTIER

Exploration and study of Earth’s subsurface has been the passion of a few but a mystery to most within geoscience until perhaps the past several decades. Increasing awareness of caves and related features has begun to penetrate into the consciousness of the wider scientific community. Growing attention to the subsurface is partly a result of acknowledgement of The Critical Zone, i.e. the interactions of the atmosphere, hydrosphere, biosphere, and near surface lithosphere. Caves are discrete systems uniquely positioned to capture these dynamic interactions that collectively describe the thin outer envelope within which all life resides, and where we conduct the vast majority of our human activities.

New non-invasive methodologies can reveal the subsurface in new ways. Ground-penetrating radar, resistivity studies, and even more exotic approaches enable discovery, reconnaissance, and mapping of cavities before any physical entry. Future refinement of such techniques will gain increasing importance.

A major new research thrust over the past 20 years is subsurface geomicrobiology, studied at depths from shallow caves and lavatubes to extremely deep mines. Unique features of subsurface microbial communities often include extreme biodiversity and a large degree of habitat partitioning. Many subsurface microbes produce a wealth of unusual chemical compounds of potential use to the pharmaceutical, industrial, and remediation communities, thus providing a major new application for speleology. Additionally, patterns of microbial biodiversity may provide useful proxies for hydrological connectivity in fractured aquifers that are difficult to measure directly.

The tantalizing prospect of extraterrestrial caves ranges from lavatubes observed on Mars and the Moon to hypothetical exotic karst in radically different planetary settings like water ice "rock" and liquid methane on Titan. The epistemological power of comparative studies can now be extended into speleology. Can we take what we believe we understand on Earth and validly translate that to another planetary body and vice versa?

In summary, speleology has been marginalized from mainstream geoscience, especially in the United States, but that situation is changing and an exciting future awaits as we go into the next 125 years of science and exploration.