![Khondalite Rock formations at Rushikonda](https://upload.wikimedia.org/wikipedia/commons/5/51/Khondalite_Rock_formations_at_Rushikonda.JPG)
Khondalite is a
foliated metamorphic rock
Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock ( protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, caus ...
. In India, it is also called ''Bezwada Gneiss'' and ''Kailasa Gneiss''.
It was named after the
Khond tribe of
Odisha
Odisha (English: , ), formerly Orissa ( the official name until 2011), is an Indian state located in Eastern India. It is the 8th largest state by area, and the 11th largest by population. The state has the third largest population of ...
and
Andhra Pradesh
Andhra Pradesh (, abbr. AP) is a state in the south-eastern coastal region of India. It is the seventh-largest state by area covering an area of and tenth-most populous state with 49,386,799 inhabitants. It is bordered by Telangana to the ...
because well-formed examples of the rock were found in the inhabited hills of these regions of eastern
India
India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and the most populous democracy in the world. Bounded by the Indian Ocean on the so ...
.
Distribution
![Khondalite rocks at a hillock near Anandapuram](https://upload.wikimedia.org/wikipedia/commons/8/8b/Khondalite_rocks_at_a_hillock_near_Anandapuram.jpg)
Khondalite is found in the
Eastern Ghats
The Eastern Ghats are a discontinuous range of mountains along India's eastern coast. The Eastern Ghats pass through Odisha, Andhra Pradesh to Tamil Nadu in the south passing some parts of Karnataka as well as Telangana. They are eroded and cut ...
between
Vijayawada
Vijayawada, formerly known as Bezawada, is the second largest city in the Indian state of Andhra Pradesh and is a part of the state's Capital Region. It is the administrative headquarters of the NTR district. Its metropolitan region comprises NT ...
and
Cuttack
Cuttack (, or officially Kataka ) in Odia is the former capital and the second largest city in the Indian state of Odisha. It is the headquarters of the Cuttack district. The name of the city is an anglicised form of ''Kataka'' which literall ...
in India.
but the term khondalite is also used to describe other rocks of similar composition found elsewhere in India as well as in
Burma
Myanmar, ; UK pronunciations: US pronunciations incl. . Note: Wikipedia's IPA conventions require indicating /r/ even in British English although only some British English speakers pronounce r at the end of syllables. As John Wells explai ...
,
Sri Lanka
Sri Lanka (, ; si, ශ්රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...
,
the northeastern Helanshan region
and the
Inner Mongolia
Inner Mongolia, officially the Inner Mongolia Autonomous Region, is an autonomous region of the People's Republic of China. Its border includes most of the length of China's border with the country of Mongolia. Inner Mongolia also accounts for a ...
region of China.
Composition
Khondalite is
quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...
–
manganese
Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...
-rich
garnet
Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives.
All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. The different s ...
–
rhodonite
Rhodonite is a manganese inosilicate, (Mn, Fe, Mg, Ca)SiO3 and member of the pyroxenoid group of minerals, crystallizing in the triclinic system. It commonly occurs as cleavable to compact masses with a rose-red color (the name comes from the G ...
schist
Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes o ...
.
It may also contain
sillimanite
Sillimanite is an aluminosilicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman (1779–1864). It was first described in 1824 for an occurrence in Chester, Connecticut.
Occurrence ...
and
graphite
Graphite () is a crystalline form of the element carbon. It consists of stacked layers of graphene. Graphite occurs naturally and is the most stable form of carbon under standard conditions. Synthetic and natural graphite are consumed on large ...
.
Feldspar
Feldspars are a group of rock-forming aluminium tectosilicate minerals, also containing other cations such as sodium, calcium, potassium, or barium. The most common members of the feldspar group are the ''plagioclase'' (sodium-calcium) feldsp ...
may occur in some cases.
Formation
Khondalites are considered to be
metasedimentary
In geology, metasedimentary rock is a type of metamorphic rock. Such a rock was first formed through the deposition and solidification of sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and er ...
rocks formed during Archaean era. According to
Lewis Leigh Fermor
Sir Lewis Leigh Fermor, OBE, FRS (18 September 1880 – 24 May 1954), was a British chemist and geologist and the first president of the Indian National Science Academy and a director of the Geological Survey of India (1930-1935). His son was ...
, the khondalite and the related
charnockite
Charnockite () is any orthopyroxene-bearing quartz-feldspar rock formed at high temperature and pressure, commonly found in granulite facies metamorphic regions, ''sensu stricto'' as an endmember of the charnockite series.
Charnockite series
Th ...
of the Eastern Ghat region were formed when the Eastern Ghat belt was faulted and buried. It was uplifted later, bringing these metamorphic rocks to the surface.
Use
Khondalites weather easily but still have been used in buildings and temples, for example, the
Konark Sun Temple
Konark Sun Temple is a (year 1250) Sun temple at Konark about northeast from Puri city on the coastline in Puri district, Odisha, India.[Jagannath Temple
The Jagannath Temple is an important Hindu temple dedicated to Jagannath, a form of Vishnu - one of the trinity of supreme divinity in Hinduism. Puri is in the state of Odisha, on the eastern coast of India. The present temple was rebuilt f ...]
.
See also
*
Gneiss
Gneiss ( ) is a common and widely distributed type of metamorphic rock. It is formed by high-temperature and high-pressure metamorphic processes acting on formations composed of igneous or sedimentary rocks. Gneiss forms at higher temperatures an ...
*
Charnockite
Charnockite () is any orthopyroxene-bearing quartz-feldspar rock formed at high temperature and pressure, commonly found in granulite facies metamorphic regions, ''sensu stricto'' as an endmember of the charnockite series.
Charnockite series
Th ...
References
Gneiss
Metamorphic rocks
Geology of India
Geology of Andhra Pradesh
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