New Formations at Oregon Caves
By Robert C. Zink, Ranger-Naturalist
The formations seen today on a trip through Oregon Caves have required centuries to be built up. Most of the water whose action formed the caves from the melting ice and snow of the Ice Age, one million years ago. Since that time, the caves were eroded and dissolved out of the mountain; stalactites and stalagmites slowly grew from the evaporation of lime solution as it dripped in the caverns. An upper opening was formed naturally 75 feet above the present Cave Entrance, from which Cave Creek emerges from the mountain. This increased the draft and consequently the rate of evaporation.
In 1930 an exit tunnel 550 feet long was drilled to the upper end of the passages adjoining the Ghost Chamber; 218 feet above the Entrance, it greatly increased draft through the caves, so that it is very noticeable at the Entrance. This increase already shows its effect. On August 10, I noticed a crack in the newly cut marble at the inner end of the exit tunnel. Through this water slowly trickles, and around it calcium carbonate has been deposited to a thickness of 1/16 of an inch. Several stalactites 3/8 of an inch long have been formed. These have been built up in these few years as a result of the warm relatively dry air entering here from outside. Beyond, however, the air is dispersed, so that its overall effect in the caves would be difficult to determine.
