GRAIN CHARACTERISTICS AND THE MINERALOGY OF MODERN GREAT MIAMI RIVER SEDIMENT SHOW COMPLEXITY AT HERITAGE PARK, COLERAIN TOWNSHIP, OHIO

The Great Miami River is a large watershed in southwest Ohio that fifteen counties are dependent on for drinking water, recreation, and agricultural use. Part of the appeal of the watershed is due to the large aquifer associated with the river. Because 1.6 million people need safe and clean water from this aquifer, it is important to understand the bulk properties of the materials. This is true particularly for modern sediments and materials in the river at the surface as infiltration pumping accounts for approximately 50% of the groundwater volume pumped for drinking. Although some investigations exist regarding the aquifer sediments in the subsurface, detailed studies of the mineralogy and grain characteristics on surficial sediment of Great Miami River is lacking. This investigation examined the mineralogical and sedimentary diversity of a location of the Great Miami River at Heritage Park in Colerain Township, Ohio. Locally derived upper Ordovician limestone lithology dominated cobble and boulder clasts (approximately 90%) whereas glacially derived igneous and metamorphic lithologies were more common in gravel size fraction. Complex coatings of carbonate and clay minerals occurred on limestone clasts. The bulk mineralogy of sand samples is variable with amounts of quartz, calcite, dolomite, albitic feldspar and K-feldspars being common. SEM investigation indicates that fine grained rare earth phosphates are somewhat common. SEM work indicates extremely variable and complex textures amongst common minerals and lithic grains. The preliminary results, combined with previous pollution work by Tully (2013) suggest that further detailed investigations of the modern sediment in the Great Miami River should be systematically investigated to understand infiltration processes that may be important for drinking water resources.