From 1997 to the present, the U.S. Geological Survey and other agencies have been collecting water samples for chemical analyses on Mount Emmons in central Colorado, USA. The geology of Mount Emmons is dominated by Upper Cretaceous to Paleogene sediments of marine to continental origin, with felsic intrusive rocks interrupting the sedimentary block. Extensive sulphide-rich alteration accompanied the intrusive events and forms an alteration halo in the sediments. Weathering of these sulphide minerals has led to numerous springs and seeps with a naturally low pH and high concentrations of metals, especially Fe and Zn. Superimposed on the natural geochemical signature are acid, metal-rich drainages from several mines and drill holes. Thus, streams on Mt. Emmons have a mix of natural and anthropogenic metal sources. Nearly 450 samples compose the database, with numerous sample locations replicated from the late 1990s to the present. Although there does not appear to be any temporal pattern in the data, consistent spatial variations are observed that allow us to characterize the natural and anthropogenic water sources.
|Title||A 20-year record of water chemistry in an alpine setting, Mount Emmons, Colorado, USA|
|Authors||Richard Wanty, Andrew H. Manning, Michaela Johnson, Philip Verplanck|
|Publication Type||Conference Paper|
|Publication Subtype||Conference Paper|
|Record Source||USGS Publications Warehouse|
|USGS Organization||Central Mineral and Environmental Resources Science Center; Geology, Geophysics, and Geochemistry Science Center|