Folded Karst, Vancouver Island

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Northern Vancouver Island, off the west coast of Canada, has a high concentration of karst cave features. Coastal forest karst ecosystems here are characterised by large units of pure carbonate bedrock, heavy rainfall, steep topography and lots of tectonic activity. The combination of a large volume of water driven by gravity, working its way through fractured soluable rock, creates hundreds of kilometres of underground passages, like this underwater cave in the Nomash Valley. Folded, skewed bedding planes of limestone and dark volcanic intrusions are evidence of incredible geological forces in this part of the world. The green cast is product of the tannic water, rich in organic matter, which leaches from the soil of the temperate rainforests covering the region. Karst gives back the rainforest too, providing better drainage and nutrient cycling compared with non-karst ecosystems. Photos by J Hjelm & N Bowman, July 2019. Exploration by Dow, Jack, Nadwidy, Norris, Richards & Richards, 2012-2015.