- GeoRef, Copyright 2008, American Geological Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Heavy mineral fractions from four Tertiary formations in Huerfano Park, Colorado, were tested statistically to see if they supported the conclusions on mode of deposition, direction of transport, and local source areas based on observable field relations. Theoretical modal size separation was also tested. Conclusions were: that the formations cannot be identified by heavy mineral composition, that interpretation of a heavy mineral correlation matrix could identify sediment from Precambrian crystalline sources and from Pennsylvanian-Permian sedimentary sources, and that statistical visual clustering and factor analysis could also differentiate different source material. Source rock characteristics caused departures from expected size frequency modes.