The Highland Rim is a geographic term for the area in
Tennessee
Tennessee ( , ), officially the State of Tennessee, is a landlocked U.S. state, state in the Southeastern United States, Southeastern region of the United States. Tennessee is the List of U.S. states and territories by area, 36th-largest by ...
surrounding the
Central Basin.
Nashville is largely surrounded by higher terrain in all directions.
Geologically, the Central Basin is a
dome. The Highland Rim is a
cuesta surrounding the basin, and the border where the difference in elevation is sharply pronounced is an
escarpment
An escarpment is a steep slope or long cliff that forms as a result of faulting or erosion and separates two relatively level areas having different elevations.
The terms ''scarp'' and ''scarp face'' are often used interchangeably with ''esca ...
. Nashville is located in the northwestern corner of the basin.
Geology and Physiography
The Highland Rim is a
physiographic section of the larger
Interior Low Plateaus
The Interior Low Plateaus are a physiographic region in eastern United States. It consists of a diverse landscape that extends from north Alabama across central Tennessee and Kentucky into southern Illinois, Indiana, and Ohio. Its natural communi ...
province, which in turn is part of the larger
Interior Plains
The Interior Plains is a vast physiographic region that spreads across the Laurentian craton of central North America, extending along the east flank of the Rocky Mountains from the Gulf Coast region to the Arctic Beaufort Sea. In Canada, it e ...
physiographic division.
Most of the Highland Rim is located in U.S.
EPA
The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...
Ecoregion
An ecoregion (ecological region) or ecozone (ecological zone) is an ecologically and geographically defined area that is smaller than a bioregion, which in turn is smaller than a biogeographic realm. Ecoregions cover relatively large areas of ...
71, Interior Plateau, which is a part of the
Eastern Temperate Forest.
The sections of the Highland Rim are referred to the four cardinal directions, e.g., "Northern Highland Rim", etc. The Highland Rim is rather continuous and any division of it, including the ones made below, are somewhat arbitrary. The term "highland" here is relative: it is certainly higher than the basin it surrounds, but it nonetheless is seldom at an elevation above above sea level and never more than about above sea level except where interrupted, primarily to the southeast, by outliers of the
Cumberland Plateau. With the exception of a few broad stream bottoms, the land is characterized by ridges and valleys with a few fairly low hills. The entire region is well watered with many perennial streams. There are occasional waterfalls which sometimes delineate the Highland Rim from the Central Basin which it surrounds.
Western Highland Rim
The Western Highland Rim is encountered a few miles west of Nashville and extends to the western valley of the
Tennessee River
The Tennessee River is the largest tributary of the Ohio River. It is approximately long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other name ...
. The area is a hilly area that is bisected by the
Tennessee River
The Tennessee River is the largest tributary of the Ohio River. It is approximately long and is located in the southeastern United States in the Tennessee Valley. The river was once popularly known as the Cherokee River, among other name ...
and the
Cumberland River valleys. Underlying bedrock of the region is chiefly
Mississippian limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms w ...
,
chert
Chert () is a hard, fine-grained sedimentary rock composed of microcrystalline or cryptocrystalline quartz, the mineral form of silicon dioxide (SiO2). Chert is characteristically of biological origin, but may also occur inorganically as a ...
,
shale, and
sandstone
Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks.
Most sandstone is composed of quartz or feldspar (both silicat ...
with exposures of
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, wh ...
,
Silurian,
Ordovician, and
Cambrian
The Cambrian Period ( ; sometimes symbolized Ꞓ) was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 53.4 million years from the end of the preceding Ediacaran Period 538.8 million years ago ...
limestone, chert, and shale.
In the northern part of the Western Highland Rim,
sinkhole
A sinkhole is a depression or hole in the ground caused by some form of collapse of the surface layer. The term is sometimes used to refer to doline, enclosed depressions that are locally also known as ''vrtače'' and shakeholes, and to openi ...
s readily occur in an area with a southern extension of the Pennyroyal plateau of Kentucky, where the
karst is best developed on the
Mississippian St. Louis Limestone
The St. Louis Limestone is a large geologic formation covering a wide area of the midwest of the United States. It is named after an exposure at St. Louis, Missouri. It consists of sedimentary limestone with scattered chert beds, including t ...
and the
Ste. Genevieve Limestone.
Eastern Highland Rim
The Eastern Rim rises approximately fifty miles east of Nashville and is bordered to its east by even higher terrain, the
Cumberland Plateau. Erosion has exposed carbonate bedrock of Late
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ...
age. These carbonate rocks contain variable amounts of chert and are often interbedded with fine grained clastic rocks. As a result, these rocks are more resistant to erosion than the underlying purer limestones of the Lower (Early) Paleozoic. The geology is diverse and is
typically limestone at valley floors (around elevation) and sandstone on ridges (to around 1,000 feet).
The constituent bedrock is composed primarily of
Mississippian aged
St. Louis, and
Warsaw
Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officiall ...
limestone
Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms w ...
s with
Fort Payne chert underlain by
Chattanooga Shale that forms a large part of the escarpment.
This area is mostly undulating plains, hills, and
karst.
Northern Highland Rim
The Northern Highland Rim is encountered a few miles north of Nashville and extends to the
Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...
border, and the region of Kentucky adjacent to it called the
Pennyroyal is largely a continuation of it under another name.
Southern Highland Rim
For the most part the Southern Rim is the farthest from Nashville, rising at some points just a few miles north of the border with
Alabama
(We dare defend our rights)
, anthem = " Alabama"
, image_map = Alabama in United States.svg
, seat = Montgomery
, LargestCity = Huntsville
, LargestCounty = Baldwin County
, LargestMetro = Greater Birmingham
, area_total_km2 = 135,7 ...
. The landforms are continuous with those in adjacent portions of Alabama, although perhaps the most spectacular landforms of any portion of the Rim are to be found there.
The stratigraphy of the Southern Highland Rim is primarily composed of flat-lying limestones,
dolomite Dolomite may refer to:
*Dolomite (mineral), a carbonate mineral
*Dolomite (rock), also known as dolostone, a sedimentary carbonate rock
*Dolomite, Alabama, United States, an unincorporated community
*Dolomite, California, United States, an unincor ...
s, and shales, and to a much lesser extent, of cherts,
siltstones,
mudstones, and very fine grained to
conglomeratic sandstones.
References
{{WikidataCoord, display=t
Regions of Tennessee
Plateaus of the United States
Landforms of Tennessee
Physiographic sections