Archean felsic volcanic rocks often causes pyroclastic flow (hot, dense gas with volcanic fragments) instead of fluid lava flow. However, if the rhyolitic lava is still molten during eruption, it can behave and flow like fluid flow. Felsic lava flow and lava dome are the two common types of underwater deposits formed by Archean felsic volcanic rocks (Fig. 4). Documented Archean lava structures are distinctive from post-Archean felsic lava because underwater eruptions are so rare in post-Archean. The dacitic or rhyolitic lava flows are quenched right after the eruption. When water is in touch with the flow, the lava quickly cools down. Finally, The
Whim Creek Copper Mine exhausted of copper oxide ore within early 2009. An option exists for the operation to continue as a sulphide operation thereafter. The Whim Creek Copper Mine extracts two volcanogenic massive sulfide ore deposits, namely Mons Cupri (lit. "copper mountain") and Whim Creek, which are located within the Cistern Formation and Rushalls Slate sedimentary members, which are part of a series of rift-related felsic, intermediate and mafic volcanic rocks known as the Whim Creek Group. The Whim Creek Group is approximately 2.9 to 2.8Ga old and lies unconformably upon an older basement of Portree Granite. The ore deposits are classified as