Geology nashville basin

The presence of the large city of Nashville, with a metropolitan population of 1. Most of the development of the Nashville Basin is in the western portion of the Outer Basin, though there are several moderate size cities in the Inner Basin.

The Inner Basin is level to gently rolling. Soils are generally thin, with frequent outcrops of Ordovician limestone. The soils are redder and lower in phosphorus than those of either the Inner Bluegrass or the Outer Nashville Basin. The karst terrain is dissected by gentle streams.

The Inner Basin is very drought prone because of the excess drainage caused by the karst topography. All the typical trees of the woodland pasture habitat are present, but usually as individual trees or small groups of trees.

The more xeric, open characteristics and shallow soils of the cedar glades also result in a distinct distribution of amphibian and reptile species. Urban, suburban, and industrial land use in the region is increasing. The Outer Basin is more variable biologically and topographically than the Inner Basin with more rolling and hilly topography and slightly higher elevations. The region is largely composed of non-cherty Ordovician limestone bedrock similar to the Inner Basin, but it includes higher hills and knobs capped by the more cherty Mississippian age formations, and some Devonian-age Chattanooga shale, remnants of the Highland Rim.

Deciduous forest and pasture the dominant non-urban land cover. The Nashville Basin rests on a dome of Ordovician limestone, the same formation that creates the Bluegrass and part of the Cincinnati Arch. The Inner Basin has a number of shale beds interrupting the limestone, while the Outer Basin includes a number of steep hills capped by chert. Limestone slowly dissolves as rain percolates through the rock.

This creates a condition known as karst, in reference to the Karst Plateau of Slovenia and Northern Italy. Rain slowly dissolves the rock, creating cracks, fissures, sinkholes and caves.

Sinkholes are common throughout the Basin. The Inner Basin is also characterized by broad exposed beds of limestone with little soil, leading to the formation of cedar glades, which are open, impoverished areas surrounded by redcedar, blue ash and other trees. Rain slowly dissolves the rock, creating cracks, fissures, sinkholes and caves. The many famous caves of Kentucky, including Mammoth Cave and Carter Caves, are in these limestone formations, although outside of the Bluegrass.

The sinkholes of the Inner Bluegrass are one of the dominant features of the pasture landscape. Small sinkholes are also found throughout the Inner Nashville Basin. Limestone is quarried in both the Bluegrass and Nashville Basin. In spite of our abundant rainfall, our streams often dry up quickly after rain, and pastures become very dry.

Karst allows rain or melting snow to percolate quickly through the soil into the underlying rock. Instead of forest and crops, the Inner Bluegrass and Inner Nashville Basin are dominated by grasslands.

Our trees are very drought tolerant and often rooted very deeply.