File:Glacial outwash (Upper Pleistocene, 15-18 ka; St. Louisville gravel pits, Licking County, Ohio, USA) 41 (44295902690).jpg

(hominids for scale)

Several ponds and lakes occur along the North Fork of the Licking River, between the towns of Newark and St. Louisville in Licking County, Ohio. These bodies of water are artificial - they are filling old gravel mines. Only one bedrock mine still operates in Licking County, plus active gravel mining.

This gravel mine is the St. Louisville Facility, owned by Shelly Materials. The company started in 1946 and has mines/quarries in 77 out of Ohio's 88 counties. This site has a sand and gravel operation, plus an asphalt plant. Mining here started in the 1980s. It is currently a wet mine - a dredging operation. Machinery extracts sand and gravel from 60 to 70 feet below the visible water surface in the ponds. The sediments are sorted into piles of sand and larger grains, including landscaping gravel. I've been told that this site produced 770,000 tons of gravel back in 2004, sold at about four American dollars per ton.

The southern and eastern edges of the mine expose a modern soil developed directly atop the sand-gravel deposit. The deposit itself is not really well-sorted overall - it's mostly a mix of sand and finer-grained gravel (pebbles). There are discrete intervals of sand interbedded with gravel-rich horizons. The deposit includes cobbles. This material is a glacial outwash deposit of Late Pleistocene age. It was deposited as the Wisconsinan Ice Sheet melted. Glaciers are more than just ice - considerable volumes of sediments are mixed in. Upon melting, the sediments get washed out. The valley containing the North Fork of the Licking River is mostly buried and filled with such glacial outwash. According to the glacial map of Ohio produced by the Ohio Geological Survey, the glacial outwash at this site is 15,000 to 18,000 years old.

The glacial outwash clasts include a wide variety of lithologies. Some have been eroded from local and near-local Ohio bedrock (e.g., Mississippian siliciclastics). Some clasts are derived from Precambrian bedrock in Canada. One distinctive clast lithology I've seen here is metatillite from the Paleoproterozoic Gowganda Formation. These metatillites are slightly metamorphosed, ancient glacial till deposits (coarse-grained, poorly-sorted, non-bedded). Such rocks are intriguing - they represent two Ice Ages in one sample: a 2.3 billion year old Ice Age deposit represented as a clast in a 15,000 to 18,000 year old Ice Age deposit.