Keywords: usgs science minerals water colorado animas outdoor In this photo, you can see a natural iron-rich acidic spring flowing into Cement Creek near Silverton, Colorado, which occurs as a result of water percolating through various heavy metals found in the ground. Similar natural springs also contribute water to Cement Creek and other tributaries of the upper Animas River. Photo credit: Briant Kimball, USGS. In this photo, you can see a natural iron-rich acidic spring flowing into Cement Creek near Silverton, Colorado, which occurs as a result of water percolating through various heavy metals found in the ground. Similar natural springs also contribute water to Cement Creek and other tributaries of the upper Animas River. Photo credit: Briant Kimball, USGS. |