TRAVELLING THROUGH TIME TO UNDERSTAND COLORADO'S THERMAL SPRINGS

As Colorado looks forward to the possibility of the first generation of geothermal electrical power generation in the next few years, now is a good time to look back on the long history and understanding of Colorado's thermal springs, including documentation of visits to some of these springs by Arthur Lakes. Native Americans were the first human users of the springs for bathing, medical, and possibly spiritual uses. They were followed by the Spanish conquistadors and migrants from the south, and eventually predominantly white explorers and prospectors from the east. All made use of the thermal springs , often building structures to capture the water. As miners, white settlers and railroads came to Colorado some of the hot spring structures became more elaborate. For example, when the railroad came through Poncha Springs in 1881, a hotel was built at Poncha Hot Springs to accommodate visitors to the steaming springs. The thermal springs were then on the map for tourists and geologists. Arthur Lakes visited Glenwood Springs in 1888 which include Yampah Hot Spring, the thermal spring with the highest flow in Colorado. Lakes described the springs and geothermal deposits at Glenwood, and then continued east to Dotsero Warm Springs where he noted the close proximity to the very young Dotsero volcano (now known to be the youngest volcanism in Colorado with an age of 4,200 BP). Lakes resisted the temptation to link the heat in the thermal springs to magmatic heat, but the most common explanation for heating the water in Colorado's thermal springs has been magmatic heat. The Colorado Geological Survey has been collecting water geochemistry data from Colorado's thermal springs since the mid-1970s. Most of the thermal waters in Colorado are low in dissolved solids and show no indication of interactions with magmatic fluids. The few waters with high dissolved solids maybe explained by chemical interaction of groundwater with sedimentary rock formations.