Document DetailsClean subglacial access: prospects for future deep hot-water drilling
|Authors:||Makinson K, Pearce D, Hodgson DA, Bentley MJ, Smith AM, Tranter M, Rose M, Ross N, Mowlem M, Parnell J, Siegert MJ|
|Keywords:||deep hot-water drilling, subglacial environment, clean access, environmental stewardship|
|Periodical/Journal:||Philosophical Transactions of the Royal Society A|
Accessing and sampling subglacial environments deep beneath the Antarctic Ice Sheet presents several challenges to existing drilling technologies. With over half of the ice sheet believed to be resting on a wet bed, drilling down to this environment must conform to international agreements on environmental stewardship and protection, making clean hot-water drilling the most viable option. Such a drill, and its water recovery system, must be capable of accessing significantly greater ice depths than previous hot-water drills, and remain fully operational after connecting with the basal hydrological system. The Subglacial Lake Ellsworth (SLE) project developed a comprehensive plan for deep (greater than 3000???m) subglacial lake research, involving the design and development of a clean deep-ice hot-water drill. However, during fieldwork in December 2012 drilling was halted after a succession of equipment issues culminated in a failure to link with a subsurface cavity and abandonment of the access holes. The lessons learned from this experience are presented here. Combining knowledge gained from these lessons with experience from other hot-water drilling programmes, and recent field testing, we describe the most viable technical options and operational procedures for future clean entry into SLE and other deep subglacial access targets.