Castles & karst |
Karst Processes Related to Climate and History
In a karst system such as Castleguard, CO2 introduced from external sources, such as soil or atmosphere, is not sufficient to explain for the extent of karstification observed.
Atmospheric CO2 sink in glaciated areas consisting of karstified carbonate rocks or other rock types including carbonate minerals can account for this. The carbon sink is known to increase during periods of increasing meltwater production. |
During the last interglacial period, Castleguard Cave developed to drain part of the Central area; the Columbia Icefield might not have existed at the time. Glacial erosion during the last glacial period disturbed the inlets to Castleguard Cave, leading to its abandonment. Eventually, the South Glacier valley was deepened, steepening all groundwater hydrological gradients in the region. During late glacial or postglacial times, a second cave system, Castleguard II, developed to drain part of the Columbia Icefield. The steeper hydrological gradients permitted a third cave system to develop; Castleguard III drains the Cathedral limestone outcrop.
While Castleguard Cave has ceased to continue developing, Castleguard II and III remain active. It is understood that karst processes in the area still remain active while the ice is still in place. At Mt. Castleguard, karst water circulation didn’t stop at any time during the last glacial period. Water supply to Castleguard Cave stopped, but a new major system was introduced beneath the Icefield. However, underground karstification is slowed or halted during the waxing phases of glacierization because there is very little water at the sole of the ice. |