Castleguard Cave, Canada
Castleguard Cave is Canada’s longest known cave and is renowned world-wide as the premier example of a cave which extends beneath an active icefield – the Columbia Icefield. The fossil system has been extensively explored from the entrance to the so called headwater complex where the cave takes on a dendritic nature and splits into a complex series of passages; a number of these end in ice-plugs several hundred meters beneath the Columbia Icefield – a unique feature of Castleguard Cave.
One lead which is relatively near to the entrance however has only been partially explored. This is the sump at the end of the Boon’s Blunder passage. The sump is of significant interest as it could provide a window into the postulated Castleguard II system which must exist beneath the known cave. The only way to solve the mystery of what lies beyond is to dive it, and has thus been the focus of two expeditions led by Martin Groves in 2009 and 2010.
The first expedition proved an all round success, with the combined UK and Canadian effort leading to 508 m of line being laid in the upstream passage of the sump. Surprisingly, Martin found the water temperature to be much higher than expected (4°C – not the anticipated 1°C) raising the mystery of where the warmth emanates from, alongside the question of what may lie beyond. With the sump still wide open and not heading towards any known section of cave, Martin was keen to return the next year to continue exploration.
The diving equipment and configuration used in 2009 had nowhere near reached its limits, which made planning for 2010 significantly easier. Now with knowledge of what to expect, the priority aim was to pass the sump. Martin describes events on the first dive:
“Crawling with my knees buried in the mud, getting bashed by the odd submerged rock I worked my way to the shore line. Firstly before getting excited I secured the dive line, but could not resist the urge to howl out, the echo reverberated down the tunnel ahead. I removed the mask and could see a Subway like tunnel disappearing into the distance. What a feeling. I started to remove my kit, I paused the seventy minute dive in had not been without incident one hand was numb as my dry glove had leaked one of my two oxygen meters had started to give strange results. I thought of the support team who must have been freezing. I knew a return would have to be made with two divers and an almost cold calculating logic told me that it would not be worth the delay of at least another hour to go for a wonder down the new passage.”
After a dive of 845 m, Boon’s Sump had been finally passed with open passage leading off into the distance. On the basis of this success the team plans to return in the Easter of 2013 with the initial aim of getting two divers through the sump to enable an accurate survey of the new extensions to be made.