Nemaha Ridge
Encyclopedia
The Nemaha Ridge is located in the Central United States. It is a buried structural zone associated with a granite
high in the Pre-Cambrian basement
that extends from approximately Omaha, Nebraska
to Oklahoma City, Oklahoma
. The ridge is associated with the seismically
active Humboldt Fault
zone. The ridge is associated with the Proterozoic
Midcontinent Rift System
which extends into northern Kansas about fifty miles west of the Nemaha Ridge. The long term uplift along the ridge has been attributed to isostatic uplift due to the anomalously thick crust
adjacent to the Midcontinent Rift.
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
high in the Pre-Cambrian basement
Basement (geology)
In geology, the terms basement and crystalline basement are used to define the rocks below a sedimentary platform or cover, or more generally any rock below sedimentary rocks or sedimentary basins that are metamorphic or igneous in origin...
that extends from approximately Omaha, Nebraska
Omaha, Nebraska
Omaha is the largest city in the state of Nebraska, United States, and is the county seat of Douglas County. It is located in the Midwestern United States on the Missouri River, about 20 miles north of the mouth of the Platte River...
to Oklahoma City, Oklahoma
Oklahoma City, Oklahoma
Oklahoma City is the capital and the largest city in the state of Oklahoma. The county seat of Oklahoma County, the city ranks 31st among United States cities in population. The city's population, from the 2010 census, was 579,999, with a metro-area population of 1,252,987 . In 2010, the Oklahoma...
. The ridge is associated with the seismically
Seismology
Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth or through other planet-like bodies. The field also includes studies of earthquake effects, such as tsunamis as well as diverse seismic sources such as volcanic, tectonic, oceanic,...
active Humboldt Fault
Humboldt Fault
The Humboldt Fault or Humboldt Fault Zone, is a normal fault or series of faults, that extends from Nebraska southwestwardly through most of Kansas....
zone. The ridge is associated with the Proterozoic
Proterozoic
The Proterozoic is a geological eon representing a period before the first abundant complex life on Earth. The name Proterozoic comes from the Greek "earlier life"...
Midcontinent Rift System
Midcontinent Rift System
The Midcontinent Rift System or Keweenawan Rift is a long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton, began to split apart during the Mesoproterozoic era of the...
which extends into northern Kansas about fifty miles west of the Nemaha Ridge. The long term uplift along the ridge has been attributed to isostatic uplift due to the anomalously thick crust
Crust (geology)
In geology, the crust is the outermost solid shell of a rocky planet or natural satellite, which is chemically distinct from the underlying mantle...
adjacent to the Midcontinent Rift.