Making Kings Mountain:
A geological overview of the park
Map of SC regions
NPS
Today, Kings Mountain National Military Park is located within the piedmont region of South Carolina. This upland region extends from the Blue Ridge Mountain on the northwest to the Sandhills on the southeast. The Sandhills coincide with the “fall line” or “fall zone,” which marks the inland termination of South Carolina’s coastal plain. Consisting mainly of Precambrian metamorphic rocks, such as schists, gneiss, and slates created more than a billion years ago, the Piedmont is geologically speaking “ancient.” Most of the soils are compact yellow and red clays that absorb run off poorly but erode quickly when deforested. Today, the topography of the park represents the remnants of a mountain range that once rivaled the modern Himalayas. What we see when we visit the region are only the roots of these once great mountains.
Over millions of years of weathering and erosion formed the gently rolling hills and wide river valleys that are characteristic of the Piedmont region. These same processes helped create the isolated mountains and ridges that dot the landscape. Known as “monadnocks,” these durable rock formations are all that’s left after the erosion of the surrounding mountains and plateaus. Kings Mountain is a classic example of a schist monadnock. It is not a volcano, active or otherwise. In geologic terms, the Piedmont and Kings Mountain were formed through a combination of accretion, folding, faulting, uplift, and erosion.
Within the Carolinas the Piedmont region is characterized by a series of terranes that run in a northeasterly direction. A terrane is an area or region that is fault-bounded and has a distinctive stratigraphy, structure, and geological history. The Carolina Terrane is a complex amalgamation of igneous, meta-igneous, and metasedimentary rocks that extends from south-central Virginia to west-Central Georgia. On the western flank of the Carolina Terrane sits the informally named Kings Mountain Sequence.
Unfortunately, the Kings Mountain Sequence is difficult to define as its shear zone has proven difficult to map. It extends northeastwards into the Winston-Salem area of North Carolina and perhaps as far south as the Georgia border. The widest section of the Kings Mountain Sequence is located near the border of North and South Carolina. This area includes the Neoproterozoic (~1 billion to 538.8 million Years Ago) Blacksburg and Battleground formations. As one might suspect, Kings Mountain National Military Park sits entirely within the Battleground formation, which extends beyond the boundaries of the park. The Kings Creek Shear zone is the boundary between the Blacksburg and Battleground formations.
Forming Kings Mountain
While there was a great deal of geological activity in earlier eras, the formation of Kings Mountain mostly took place during the Cenozoic Era (~66 million Years Ago). Running water and wind played prominent roles in the erosion and weathering of the Southern Appalachians. Large rivers and their tributaries ran through the region, which, along with the winds, stripped sediments and gravel. This process worked to lower the mountains, while the sediments were deposited in alluvial terraces and alluvium. It is estimated, based on the amount of metamorphic rock exposed in the Blue Ridge Mountains, that vast quantities of sediment were removed through erosion and weathering. In some cases, it is believed that the exposed rocks were at least 10mi or 20km below the surface at one point.
During the Pleistocene ice ages (2.58 million to 11,700 years ago), the glaciers that covered much of the earth’s surface never made it as far as the Southern Appalachians. Nevertheless, the ice ages did play a role in the formation of Kings Mountain. During the period, the climate was much wetter, vegetation was sparse, and the ground was frozen. This led to increased precipitation and runoff, which fed the region’s mighty rivers. Such conditions increased the processes of downcutting and erosion caused by the rivers. Finally, many of the boulders, block fields, and fine-textured colluvium on the forested mountainsides were created by frost wedging.
Root Wedging
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Today erosion, weathering, and slope processes continue to shape Kings Mountain and the surrounding landscape. Unfortunately, they also cause mass wasting, which is an important resource management issue. In the wet mountainous terrain of the park, landslides, slope creep, and debris flows are common. Along with natural erosion, roads, trails, and other artificially altered landscapes increase the likelihood of slope failures. Slopes that lack stabilizing vegetation, are undercut by waterflow, suffer from frost or root wedging, or are regularly and quickly saturated by rain can become unstable. It is, therefore, important for visitors to do their part to help preserve the park landscape by staying on designated trails.
Civilian Conservation Corps doing roadwork at Kings Mountain
NPS
Topography and Geology
of Kings Mountain
The topography of the park is characterized by dissected uplands of relatively low relief. Linear ridges and hills rise abruptly 100-800ft (30-240m) above the surrounding rolling hills and form precipitous cliffs at Crowders Mountain and the Pinnacle. Within the park, elevation ranges from 646ft (197m) at Kings Creek on the northwest boundary of the park, to 1,060 ft (323m) at the top of Bushy Ridge, a spur of the Kings Mountain range. The linear hills and ridges of the park are mostly underlain by erosion-resistant quartzite and quartz-pebble conglomerate. Bushy Ridge, however, is underlain by siliceous-metatuff, which is also quite erosion resistant. Thick saprolite mantles much of the bedrock, and regolith fills in the areas of lower relief. However, in some areas, streams cut through the overburden, exposing the bedrock along their courses.
A stream along a park recreation trail.
NPS
Kings Mountain is itself a classic monadnock, or erosional remnant, that rises about 60ft (18m) above the surrounding landscape. The highest point of Kings Mountain has an elevation of 1,019 ft (310.59m). It is defined by the narrow ridge, only 60-100ft (18-30m) that runs along the top. The mountaintops are underlain by more resistant metasedimentary quartzite, metaconglomerate, and metavolcanic rocks, while the ridgeline is underlain by siliceous metatuff.
Kings Mountain sequence of the Carolina Terrane
Kings Mountain National Military Park encompasses and area of 3,945 acres. This means that Kings Mountain only accounts for a relatively small portion of the park’s total area. Besides Kings Mountain, there are several major geologic units that can be found within the boundaries of the park. These include Quartz-Sericite Phyllite and Schist, Mottled Phyllitic Metatuff, Plagioclase-Crystal Metatuff, Metatonalite, Siliceous Metatuff, Volcanic Metaconglomerate, Dixon Gap Metaconglomerate Member, Jumping Branch Manganiferous Member, and Alluvium.
Glossary for the Geology
of Kings Mountain
Accretion: The process by which material is added to a tectonic plate at a subduction zone, frequently on the edge of existing continental landmasses Alluvium: Stream-deposited sediment Alluvial terrace: A stream terrace composed of unconsolidated alluvium, produced by renewed downcutting of the flood plain or valley floor Batholith: A massive, discordant pluton, greater than 40mi2/100km2, and commonly formed from multiple intrusions Block fields: a surface covered by boulder- or block-sized rocks Debris Flow: A moving mass of rock fragments, soil, and mud, more than half the particles of which are larger than sand Downcutting: a geological process by hydraulic action that deepens the channel of a stream or valley by removing material from the stream's bed or the valley's floor Colluvium: A general term applied to any loose, heterogeneous, and incoherent mass of soil material and/or rock fragments deposited by rainwash, sheetwash, or slow, continuous downslope creep, usually collecting at the base of gentle slopes or hillsides Fall line/Fall zone: The imaginary line between two parallel rivers, at the point where rivers plunge, or fall, at roughly the same elevation Fault: A break in rock along which relative movement has occurred between two sides Fold: A stack of originally planar surfaces that are bent or curved during permanent deformation Formation: A fundamental rock-stratigraphic unit that is mappable, lithographically distinct from the adjoining strata, and has definable upper and lower contacts Frost Wedging: The breakup of rock due to the expansion of water freezing in fractures Glacier: A large, perennial accumulation of crystalline ice, snow, rock, sediment, and often liquid water that originates on land and moves down slope under the influence of its own weight and gravity Mass Wasting: A general term for the downslope movement of soil and rock material under the direct influence of gravity Meta-: A prefix used with the same name of a sedimentary or igneous rock, indicating the rock has been metamorphosed Metamorphism: A change in rocks through mineral alteration, genesis, and/or recrystallization from increased heat and pressure Mineral: A naturally occurring, inorganic crystalline solid with a definite chemical composition or compositional range Monadnock: An isolated erosional remnant rising above the surrounding landscape Piedmont: An area at the bas of a mountain or mountain range Phyllite: A metamorphosed rock with a silky sheen, intermediate in composition between slate and mica schist Quartzite: A hard, non-foliated metamorphic rock which was originally pure quartz sandstone Regolith: General term for the layer of rock debris, organic matter, and soil that commonly forms the land surface and overlies most bedrock Root wedging: A process where plants and their roots wedge into cracks in bedrock, and widen them Saprolite: Soft, often clay rich, decomposed rock formed in place by chemical weathering Sediment: An eroded or deposited, unconsolidated accumulation of rock and mineral fragments Sequence: A major informal rock-stratigraphic unit that is traceable over large areas and defined by a major sea level transgression-regression sediment package Shear zone: A thin zone within the Earth's crust or upper mantle that has been strongly deformed, due to the walls of rock on either side of the zone slipping past each other Siliceous: Any of a group of sedimentary rocks that consist largely or almost entirely of silicon dioxide (SiO2), either as quartz or as amorphous silica and cristobalite Slope creep: The imperceptibly slow, steady, downward movement of slope-forming soil or rock Slope failures: A phenomenon that a slope collapses abruptly due to weakened self-retainability of the earth under the influence of a rainfall or an earthquake Spur: A long, gently-sloping 'tongue' of ground formed by erosion that runs down from a hill to a lower ground Stratigraphy: The geologic study of the origin, occurrence, distribution, classification, correlation, and age of rock layers especially sedimentary rocksTerrane: A large region or group of rocks with similar geology, age, or structural style Topography: The general morphology of the Earth’s surface, including relief and locations of natural and anthropogenic features Tuff: Generally fine-grained igneous rock formed of consolidated volcanic ash Uplift: A structurally high area in the crust, produced by movement that raises rocks Weathering: The set of physical, chemical, and biological processes by which rock is broken down
