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The Wells Gray Park Cave discovery concerns the 2018 discovery of a karst cave in Wells Gray Provincial Park, in the Cariboo Mountains in British Columbia, Canada. The cave has informally been named Sarlacc's Pit but is pending an official name.[1]

Wells Gray Park Cave[a]
Circling Above the Cave.png
An aerial view of the cave entrance.
LocationWells Gray Provincial Park
Coordinates52°30′59.8″N 120°02′36.2″W / 52.516611°N 120.043389°W / 52.516611; -120.043389
Depth500 m (1,600 ft) (est.)
Length2,100 m (6,900 ft) (est.)
DiscoveryApril 2018
Geologystripe karst
Hazardsmeltwater flow


Discovery and explorationEdit

In the spring of 2018, a team working for the British Columbia Ministry of Forests, Lands, Natural Resource Operations and Rural Development was surveying caribou populations by helicopter when the pilot, Ken Lancour, spotted the deep, snow-filled cavity.[2][3][4][5][6] The cave was dubbed “Sarlacc’s Pit” by the discovery group due do its similarity with the lair of Sarlacc, a creature from the Star Wars film Return of the Jedi. Formal naming is pending First Nations consultation.[7][1][8][4]

In September 2018, a team led by geologist Catherine Hickson and archaeological surveyor John Pollack returned to the site and made a partial descent into the cave once it was snow-free.[4][8][3][1] Planning for the short one-day reconnaissance visit began with the assistance and support of BC Park’s staff Vladimira Gat and Tod Haughton. The ground reconnaissance expedition determined the physical dimensions of the cave.[9] The vertical section forming the cave is both very large and deep. In plan view the entrance pit is 100 m (330 ft) long by 60 m (200 ft) wide, with an overhanging drop on the high side exceeding 120 m (390 ft). The true depth of the cave could not be measured due to mist from a fast flowing, turbulent river that flows into the cave, but is estimated to be at least 180 m (590 ft) deep and 2.1 kilometres (1.3 mi) long. The team plans to return for more extensive explorations in 2020.[8][1][4]

The expedition was a flag expedition of the Royal Canadian Geographical Society. It was funded by Catherine Hickson, John Pollack, Lee Hollis, Tuya Terra Geo Corp., BC Park, Cody Cave Tours, Yellowhead Helicopters, Susan Dalby and Eskild Peterson.[10][11][12]

In December 2018 the Government of British Columbia closed the area around the cave in the interests of preservation and public safety.[13][14]

Geography and geologyEdit

Sarlacc's Pit is suspected to be the largest known stripe karst cave.[1][3] However, it is not likely to be the deepest stripe karst cave if the current spring exit is proven. The Cascade Tupper System in Roger’s Pass is deeper at around 483 m (connection proven by dye tracing), and White Rabbit is likely over 1 km in depth.[15][16] Preliminary estimates also suggest it may be the largest cave entrance in Canada.[1] Its entrance is 100 metres (330 ft) long by 60 metres (200 ft) wide.[4][8][3][1] It is at least 135 metres (443 ft) deep.[1]

The cave is normally snow-covered for much of the year and sits at the bottom of a massive avalanche slope.[4][8] Winter may be the only practical season to explore the cave due to low base flow; in spring, meltwater flow of between 5 to 15 cubic metres per second (177 to 530 cu ft/s) prevents entrance.[4] The cave may have been snow-covered year-round until the 20th century (this is supposition – likely the late Wisconsinan Glaciation covered the entrance until a few thousand years ago), which would suggest that it has not been explored by First Nations people. The technical gear required, combined with the depth of the entrance shaft, means passing mountaineers in the last few decades are unlikely to have explored it either.[4][8] A river flows into the entrance, becoming a waterfall and sending up mist that has prevented measuring the exact depth of the cave.[3][1]

Stripe karst is marble (principally calcium carbonate) interbedded with rock units containing less marble. These interbedded units are often garnet, mica, schist, and quartzite. The interlayering of the three kinds of rocks gives the overall rock mass a striped look, hence the name stripe karst. Stripe karst tends to be discontinuous[17] and because the rocks have been subjected to a high degree of metamorphism, they are often folded and highly contorted.[18]

The rocks within which the cave formed are steeply NE dipping intensely folded marble units 1–10 m in thickness. The marble units are intercalated with garnet mica schist layers of similar thickness with minor quartzite. These units have been mapped as Kootenay Terrane of Proterozoic and perhaps Paleozoic age; and are most likely the “main marble” unit. The valley is parallel with a major stratigraphic break between the Kootenay Terrane rocks and Upper Proterozoic Windermere Supergroup rocks, and are most likely the Isaac Formation.[18] The cave likely formed from a combination of hydraulic milling (largely in a subglacial to periglacial environment) and dissolution. A complex set of fractures and fault intersections are coincident with the cave opening. Topographically, the valley has a bedrock ridge just downslope of the cave. This formed an upslope depression and ponding area that likely focused dissolution and erosion at the location of the cave during the early stages of its formation. It is hypothesized that once a depression was formed, dissolution and erosion continued over tens of thousands of years to create the cave.[19][20]

Topographically the cave is significantly downslope from the peaks and ridges that surround it. Viewed from upslope, it is hard to discern that it is not just another rocky knoll along the valley bottom.

The Wells Gray area has been subject to several continental scale glaciations in the past 2.6 million years, and the cave may have formed from meltwater flowing beneath the resultant glaciers (this is seen elsewhere in the vicinity).[21] There may have been a cave prior to the continental scale glaciations, but it was probably largely destroyed by the glaciers. Nevertheless, some of this proto-cave may have survived within the current cave system as ancient passageways. Only further exploration will reveal this. In glacial times the sub-glacial flow appears to have targeted the thin (1–10 m) steeply-dipping marble strata, promoting the dissolution and erosion of these marble units. The prominent fractures and faults that cut the strata enhanced erosion. In addition, it should be noted that the interlayered rocks between the marble units (schist and quartzite) are resistant to chemical attack by the carbon dioxide dissolved in the flowing water. The subterranean river seen at the swallet eventually resurfaces more than 2 km (1.2 mi) away, around 460 m (1,510 ft) lower in altitude, in a larger valley.[22] Today, the glaciers have receded, but still deliver a massive amount of water to the cave.[23]

Provincial and national significanceEdit

Pollack and Chas Yonge believe this feature is among the largest karst cave entrances in Canada. In British Columbia (BC), comparable caves would include Devil’s Bath—a 100 to 120 m (330 to 390 ft) diameter water-filled sink—and Vanishing River, both on northern Vancouver Island[24] The latter is a river sink notably smaller in dimension than Sarlacc’s Pit that takes a large surface stream of variable flow. There is also the Moon River Cave in east central BC, which takes a large stream, and the White Rabbit entrance in the northern Selkirk Mountains of BC, both of which have very large entrances and have been mapped.[25][26]

In the Northwest Territories (NWT), there are several large karst features including the Vermillion Creek Collapse—a vertically walled sinkhole in shaly limestones overlying gypsum.[27] The Vermillion Creek Collapse ends in water, and has no discernible continuation. It is 120 by 60 m (390 by 200 ft) wide by 40 m (130 ft) deep.

Also, in the NWT is the Disappearing River near the Hare Indian River Plateau. Ford noted at the time that the Disappearing River is one of the finest examples of a sinking river in Canada, and gauged the flow at 10 litres per second in late July. However, the Sarlacc’s Pit Cave’s river is significantly larger. Neither the Vermillion Creek Collapse nor the Disappearing River have open cave passages. However, the Moraine Polje, a 90 km2 (35 sq mi) drainage area on the Keele River, NWT, has a partially explored cave running approximately 1.3 km (0.81 mi) between sink and the resurgence (point where the water in the cave exits to the surface). No flow data has been published. The karst of the Nahanni River, NWT also has very large sinking features.[28]

Finally, there is the sink of the Salmon River on Anticosti Island, Quebec.[29] which has a catchment area exceeding 140 km2 (54 sq mi). This feature, and the diffuse sink of the Medicine River in Jasper National Park, are likely the greatest river sinks known in Canada.[citation needed]

See alsoEdit



  1. ^ The official name of the cave has not yet been determined as of December 2018


  1. ^ a b c d e f g h i The Canadian Press (3 December 2018). "Newly discovered cave in B.C. might be largest ever found in Canada". CBC News. Retrieved 3 December 2018.
  2. ^ "Newly discovered cave in B.C. might be largest ever found in Canada". CBC News. Canadian Press. 3 December 2018. Retrieved 3 December 2018.
  3. ^ a b c d e "'Awe-inspiring' cave discovered in Canada's wilderness". BBC News. 3 December 2018. Retrieved 3 December 2018.
  4. ^ a b c d e f g h Wilson, Harry (30 November 2018). "Canadian team confirms presence of huge unexplored cave in British Columbia". Canadian Geographic. Canadian Geographic Enterprises. Retrieved 2 December 2018.
  5. ^ "'Awe-inspiring' cave discovered in Canada's wilderness". BBC News. BBC News. 3 December 2018. Retrieved 3 December 2018.
  6. ^ Wilson, Harry (30 November 2018). "Canadian team confirms presence of huge unexplored cave in British Columbia". Canadian Geographic. Canadian Geographic Enterprises. Retrieved 2 December 2018.
  7. ^ "Consulting with First Nations". BC Ministry of Environmental Protection and Sustainability. Retrieved 10 December 2018.
  8. ^ a b c d e f Little, Simon (2 December 2018). "Massive, unexplored 'cave of national significance' discovered in B.C. park". Global News. Retrieved 3 December 2018.
  9. ^ Little, Simon (2 December 2018). "Massive, unexplored 'cave of national significance' discovered in B.C. park". Global TV News. Corus. Retrieved 3 December 2018.
  10. ^ "Cody Cave Tours". Cody Cave Tours. Retrieved 2018-12-14.
  11. ^ "Home". Retrieved 2018-12-14.
  12. ^ "Yellowhead Helicopters Ltd provides commercial helicopter solutions". Retrieved 2018-12-14.
  13. ^ Schmunk, Rhianna (Dec 19, 2018). "Visiting B.C.'s huge, newly discovered cave could land you a $1M fine". CBC News. Retrieved 20 December 2018.
  14. ^ "Wells Gray Park Closure Notice December 17, 2018". Wells Gray Park. Retrieved 20 December 2018.
  15. ^ Yonge, C.J., Viera, N. and Walker, N. (2013). "The Tupper – Raspberry Rising Cave System: A Remarkable Example in Stripe Karst". 16th International Congress of Speleology. ICS Proceedings, BRNO Czech Republic: 158–163.CS1 maint: Multiple names: authors list (link)
  16. ^ Yonge, C.J. (2018). "White Rabbit, Monashee - Geology, Speleogenesis and Cave Depth Potential". Canadian Caver. 84: 5–9.
  17. ^ Karst Task Force (2001). Karst Inventory Standards and Vulnerability Assessment Procedures for British Columbia. Province of British Columbia. ISBN 978-0-7726-4488-6.
  18. ^ a b Murphy, D.C. (2007). Geology, Canoe River, British Columbia-Alberta, Map 2110A, Scale 1:250,000. Natural Resources Canada. Geological Survey of Canada.
  19. ^ Cave Model.
  20. ^ Cave Modelling.
  21. ^ Smart, C.C. (1983). "The Hydrology of the Castleguard Karst, Columbia Icefields, Alberta, Canada". Arctic and Alpine Research. 15: 471–486. doi:10.1080/00040851.1983.12004375 (inactive 2019-03-08).
  22. ^ View from Above of Meltwater Flowing into Cave.
  23. ^ Meltwater Flowing into Cave. Retrieved 13 December 2018.
  24. ^ Pollack 2018 pers. comm.
  25. ^ Yonge, C. (2018). "The White Rabbit Marble Cave, Monashee Mountains, BC, Canada: A Remarkable Cave System in Stripe Karst". Canadian Caver (In press).
  26. ^ McKenzie, I. (1988). "Men in the Moon". Canadian Caver. 20 (1): 7–12.
  27. ^ Ford, Derek (2008). Report Upon a Survey of Karst Landforms Around Norman Wells, Northwest Territories. NWT Protected Areas Strategy Department of Environment and Natural Resources Government of the Northwest Territories.
  28. ^ Horne, G. (2008). "The North Karst, South Nahanni River Area". Canadian Caver. 68 (1): 4–9.
  29. ^ Roberge, J.; Ford, D.C. (February 1983). "The Upper Salmon River karst, Anticosti Island, Quebec, Canada". Journal of Hydrology. 61 (1–3): 159–162. doi:10.1016/0022-1694(83)90241-X.

External linksEdit