
Freeze Shoe
The freeze shoe tool is a wireline drilling tool using CO2 cooling techniques to freeze the bottom ~10cm of a coring run in situ, to capture and retrieve soft sediment samples with pore waters intact and uncompromised by mixing or oxidation during recovery, for analysis of microbial communities, minerals, or other constituents that are easily altered during the recovery process.
Modified from the HPC and ALN soft sediment coring tools, the freeze shoe is a P-size tool that collects a 1 meter long, HQ3-size core (61.1mm diameter) in a polycarbonate tube, with the bottom ~15 cm frozen. After drilling the 1 meter run, the tool sits in place briefly while the freezing progresses. The tool is returned to the surface and the core is extracted.