Borra Caves
Encyclopedia
The Borra Caves, also called Borra Guhalu in Telugu language
(‘Borra’ means something that has bored into the ground and ‘guhalu’ means caves), are located on the East Coast of India, in the Ananthagiri hills of the Araku valley
(with hill ranges elevation varying from 800 m (2,624.7 ft) to 1300 m (4,265.1 ft)) of the Visakhapatnam district
in Andhra Pradesh
. The Caves, one of the largest in the country, at an elevation of about 705 m (2,313 ft), distinctly exhibit a variety of impressive speleothems(pictured) ranging from very small to big and irregularly shaped stalactites and stalagmites. The Caves are basically Karstic limestone
structures extending to a depth of 80 m (262.5 ft) (considered the deepest cave in India).
, which he interpreted as the Lord Shiva
who protected the cow. The village folk who heard the story believed it and since then they have built a small temple for Lord Shiva outside the cave. People flock to the temple for worship and the cave to get a glimpse of the Lingam.
Another lyrical legend is that the Shiva
Lingam
representing the Hindu
God Lord Shiva
, is found deep in the caves and above which is a stone formation of a cow (Sanskrit
: Kamadhenu
). It is surmised that the udder of this cow is the source of the Gosthani (Sanskrit: Cow’s udder) River which originates from here, flows through Vizianagram and Visakhapatnam districts before debouching into the Bay of Bengal
near Bheemunipatnam
.
of the Ananthagiri hill range and is drained by the Gosthani River. At the entry, the cave measures up to 100 m (328.1 ft) horizontally and 75 m (246.1 ft) vertically. Stalagmite and Stalactite formations are found in the caves.
The average annual temperature
of Araku hills, where the caves are situated, is about 25 °C (77 °F). The average annual rainfall reported is 950 mm (3.1 ft) (mostly occurring during the northeast monsoon
). The Gosthani river provides water supply to the Visakhapatnam
city.
.svg.png)
The Regional Geology in the Eastern Ghats
mobile belt, where the caves are located, is represented by the Khondalite suite of rocks (garnetiferrous sillimanite
gneisses, quartz
o-feldsphatic garnet
gneisses) of Archaen age. Quaternary deposits consist of red bed sediments, laterite
s, pediment fans, colluvium
, alluvium
and coastal sands
. Particularly, the Borra caves are stated to be one of the largest caves in the Indian subcontinent
.
The caves, in the reserved forest area consisting of 14 villages inhabited by tribals, basically host a variety of speleothems ranging from very small to big and irregularly shaped stalactites and stalagmites. The carbonate
rocks are pure white
, and coarsely crystalline and the deformed and banded marbles
cover a triangular area of 2 square kilometre; surrounded by Diopside
–scapolite
–feldspar
calc-granulites. The pyroxenite
outcrops are dark and massive and include discontinuous calc-silicate bands, some of brown mica
and others with calcite
.
The Gosthani River, which originates from these caves and flows between the solidified stalactites and stalagmites in the Karstic lime stones formation, is the cause for the development of the odd shapes of structures. Water percolating from the roof of the caves dissolve limestone
and trickle drop by drop to form stalactite
at the roof of the cave and then dripping down to the ground form stalagmite
. (see picture). Stalactites are calcium carbonate
deposits that hang from the top of the cave. Stalagmites are deposits that form at the bottom of the cave and grow upward. These deposits have developed into interesting forms and structures inside the caves such as Shiva
–Parvati
, Mother–Child, Rishi
’s beard, Human brain
, mushrooms, crocodile
, temple
, church, etc. These shapes have captured the imagination of tourists, while some have been given religious interpretations.
The Caves are deep and totally aphotic. There is a twilight zone in the caves with limited light penetration. The Stalactites seen in the caves are about 0.1 m (0.328083989501312 ft) to 3.5 m (11.5 ft) in length while the Stalagmites are 1.2 m (3.9 ft) long and columns are 6 m (19.7 ft) in height and 0.75 m (2.5 ft) in width. The height of the cave is 12 m (39.4 ft) and the length is about 200 m (656.2 ft). The average temperature of the inner cave wall is reported to be about 16 °C (60.8 °F). Sulphur springs
discharge into the cave passages causing corrosion
of limestone. The spring waters display floating Mucus
-like biofilms. These are thick orange microbial mats (2.5 cm (0.984251968503937 in)–3 cm (1.2 in) thick) with patches of yellow biofilms extending 3 m (9.8 ft) from the aphotic deep cave orifice.
While the caves are basically limestone formations, the area surrounding these are of mica
formations which are prospected for precious stones like rubies.
The geological features of these caves are stated to be found only in Borra in India. Archeological artifacts
(Paleolithic
implements) have been found in the caves. The excavations carried out in the caves by the Archeologists of the Andhra University, have unearthed stone tools of middle Paleolithic culture dating back to 30,000 to 50,000 years, which confirm human habitation.
carbonates (considered as inorganic precipitates) found in the caves have been subject to scientific studies. In fluviatile, spring, cave and soil environments Microbial carbonates are important. In the biofilms and/or microbial mats, which are formed in the caves, the principal organisms associated are bacteria
, particularly cyanobacteria, small algae
and fungi. Petrographic analysis of a thin section has uncovered the presence of lithified structures and micrite
, present as laminated to clotted with chocolate-brown blebs. These are identical to microbialites observed in modern and ancient stromatolitic carbonates. Laboratory observations with Scanning Electron Microscope (SEM) have also confirmed the presence of calcified bacteria
, micro-rods, and needle calcite
. Organic mats (yellow-orange in colour) comprise of mineralized filamentous bacteria
, bacterial stalks, cells
and sheaths. Thus, these studies have indicated that biological (microorganisms) have actively influenced in the genesis of speleothem carbonates of the Borra Caves.
The abstract of their report states:
observed in the caves are predominantly bats, as well as the golden gecko
. The type of bat reported is the fulvous fruit bat (Rousettus leschenaultii) – a species which roosts in large caves, old buildings, dungeons and dark areas of old forts. This species has short and slender musculature with large, well developed eyes. They feed on flowers and fruits, particularly jamun, guava
, silk
, cotton
and mango
.
The forests in the area are of semi-evergreen deciduous
type. The flora in the cave consist of mosses and brown-to-green algae
. Since many of the species found are endangered, mining
operations are considered to be in violation of the Environmental Protection Act.
, rail
and air services. Vishkapatnam, the nearest airport
and the district headquarters, is 90 km (55.9 mi) by road, which is mostly a hill road and the journey takes about 3 hours.
Train services operate on the Kothavalasa
-Kirandul
railway line in East Coast Railway
, Indian Railways
. The train journey over a distance of 100 km (62.1 mi)from the Vishkapatanam Rly station passes through Eastern Ghats (hill) section), which has 30 tunnels en-route. The journey by train takes about 5 hours to the Railway Station near the caves called the ‘Borra Guhalu Railway station’.
Plantation
, Padmapuram Gardens and the Araku Valley. For the benefit of the visitors, an information board at the entry point to the caves gives some details of the caves and its surroundings (pictured).
An Arraku and Borra rail-cum-road package tour organized by the Andhra Pradesh State Tourism Department is available for visitors keen to see the Borra caves.
A walk around the caves provides an impressive view of the mountainous area which is rich in flora
and fauna
. The Andhra Pradesh State Tourism Department has installed 26 mercury
, sodium vapor and halogen
electric lamps, which provide beautiful views of the formations (pictured). Geologist
s and tourists visiting the caves are enchanted by the lighted caves. The Araku valley, a famous hill station, about 29 km (18 mi) from the Borra caves is also an interesting tourist attraction for people visiting the caves.
November and December are ideal months to visit the caves. The caves are open to visitors from 10 am to 5:30 pm.
Telugu language
Telugu is a Central Dravidian language primarily spoken in the state of Andhra Pradesh, India, where it is an official language. It is also spoken in the neighbouring states of Chattisgarh, Karnataka, Maharashtra, Orissa and Tamil Nadu...
(‘Borra’ means something that has bored into the ground and ‘guhalu’ means caves), are located on the East Coast of India, in the Ananthagiri hills of the Araku valley
Araku Valley
Araku Valley is a hill station and a Mandal in Visakhapatnam district in the state of Andhra Pradesh in India.It has got an amazing nature with thick forests surrounded all over.Araku is popular for its world famous coffee plantations.For every traveller it gives a wonderful and a unique...
(with hill ranges elevation varying from 800 m (2,624.7 ft) to 1300 m (4,265.1 ft)) of the Visakhapatnam district
Visakhapatnam district
Visakhapatnam district , also known as Visakha Zilla, is an administrative division of Andhra Pradesh, India. The administrative headquarters of the Visakhapatnam District is Visakhapatnam.-Post-Independence:...
in Andhra Pradesh
Andhra Pradesh
Andhra Pradesh , is one of the 28 states of India, situated on the southeastern coast of India. It is India's fourth largest state by area and fifth largest by population. Its capital and largest city by population is Hyderabad.The total GDP of Andhra Pradesh is $100 billion and is ranked third...
. The Caves, one of the largest in the country, at an elevation of about 705 m (2,313 ft), distinctly exhibit a variety of impressive speleothems(pictured) ranging from very small to big and irregularly shaped stalactites and stalagmites. The Caves are basically Karstic limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
structures extending to a depth of 80 m (262.5 ft) (considered the deepest cave in India).
Legend
On the discovery of the caves, there are several legends, which the tribals (Jatapu, Porja, Kondadora, Nookadora, valmiki etc.) who inhabit the villages around the caves narrate. The popular legend is that a cow, grazing on the top of the caves, dropped 60 m (196.9 ft), through a hole in the roof. The cowherd while searching for the cow came across the caves. He found a stone inside the cave that resembled a LingamLingam
The Lingam is a representation of the Hindu deity Shiva used for worship in temples....
, which he interpreted as the Lord Shiva
Shiva
Shiva is a major Hindu deity, and is the destroyer god or transformer among the Trimurti, the Hindu Trinity of the primary aspects of the divine. God Shiva is a yogi who has notice of everything that happens in the world and is the main aspect of life. Yet one with great power lives a life of a...
who protected the cow. The village folk who heard the story believed it and since then they have built a small temple for Lord Shiva outside the cave. People flock to the temple for worship and the cave to get a glimpse of the Lingam.
Shiva
Shiva is a major Hindu deity, and is the destroyer god or transformer among the Trimurti, the Hindu Trinity of the primary aspects of the divine. God Shiva is a yogi who has notice of everything that happens in the world and is the main aspect of life. Yet one with great power lives a life of a...
Lingam
Lingam
The Lingam is a representation of the Hindu deity Shiva used for worship in temples....
representing the Hindu
Hindu
Hindu refers to an identity associated with the philosophical, religious and cultural systems that are indigenous to the Indian subcontinent. As used in the Constitution of India, the word "Hindu" is also attributed to all persons professing any Indian religion...
God Lord Shiva
Shiva
Shiva is a major Hindu deity, and is the destroyer god or transformer among the Trimurti, the Hindu Trinity of the primary aspects of the divine. God Shiva is a yogi who has notice of everything that happens in the world and is the main aspect of life. Yet one with great power lives a life of a...
, is found deep in the caves and above which is a stone formation of a cow (Sanskrit
Sanskrit
Sanskrit , is a historical Indo-Aryan language and the primary liturgical language of Hinduism, Jainism and Buddhism.Buddhism: besides Pali, see Buddhist Hybrid Sanskrit Today, it is listed as one of the 22 scheduled languages of India and is an official language of the state of Uttarakhand...
: Kamadhenu
Kamadhenu
Kamadhenu , also known as Surabhi , is a divine bovine-goddess described in Hindu mythology as the mother of all cows. She is a miraculous "cow of plenty" who provides her owner whatever he desires and is often portrayed as the mother of other cattle as well as the eleven Rudras...
). It is surmised that the udder of this cow is the source of the Gosthani (Sanskrit: Cow’s udder) River which originates from here, flows through Vizianagram and Visakhapatnam districts before debouching into the Bay of Bengal
Bay of Bengal
The Bay of Bengal , the largest bay in the world, forms the northeastern part of the Indian Ocean. It resembles a triangle in shape, and is bordered mostly by the Eastern Coast of India, southern coast of Bangladesh and Sri Lanka to the west and Burma and the Andaman and Nicobar Islands to the...
near Bheemunipatnam
Bheemunipatnam
Bheemunipatnam , is a town, a municipality and mandal headquarters in Visakhapatnam district, in the state of Andhra Pradesh, India.It was the second municipality in Indian mainland, established on 9 February 1861. 150-Years of its formation has been celebrated in 2011.Bheemunipatnam is supposed to...
.
Geography and climate
The caves are located in the Araku ValleyAraku Valley
Araku Valley is a hill station and a Mandal in Visakhapatnam district in the state of Andhra Pradesh in India.It has got an amazing nature with thick forests surrounded all over.Araku is popular for its world famous coffee plantations.For every traveller it gives a wonderful and a unique...
of the Ananthagiri hill range and is drained by the Gosthani River. At the entry, the cave measures up to 100 m (328.1 ft) horizontally and 75 m (246.1 ft) vertically. Stalagmite and Stalactite formations are found in the caves.
The average annual temperature
Temperature
Temperature is a physical property of matter that quantitatively expresses the common notions of hot and cold. Objects of low temperature are cold, while various degrees of higher temperatures are referred to as warm or hot...
of Araku hills, where the caves are situated, is about 25 °C (77 °F). The average annual rainfall reported is 950 mm (3.1 ft) (mostly occurring during the northeast monsoon
Monsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
). The Gosthani river provides water supply to the Visakhapatnam
Visakhapatnam
Visakhapatnam is a major sea port on the south east coast of India. With a population of approximately 1.7 million, it is the second largest city in the state of Andhra Pradesh and the third largest city on the east coast of India after Kolkata and Chennai. According to the history, the city was...
city.
Geology
Eastern Ghats
The Eastern Ghats or Eastern Ghauts are a discontinuous range of mountains along India's eastern coast. The Eastern Ghats run from West Bengal state in the north, through Orissa and Andhra Pradesh to Tamil Nadu in the south passing some parts of Karnataka. They are eroded and cut through by the...
mobile belt, where the caves are located, is represented by the Khondalite suite of rocks (garnetiferrous sillimanite
Sillimanite
Sillimanite is an alumino-silicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman . It was first described in 1824 for an occurrence in Chester, Middlesex County, Connecticut, USA....
gneisses, quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
o-feldsphatic garnet
Garnet
The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones and abrasives. The name "garnet" may come from either the Middle English word gernet meaning 'dark red', or the Latin granatus , possibly a reference to the Punica granatum , a plant with red seeds...
gneisses) of Archaen age. Quaternary deposits consist of red bed sediments, laterite
Laterite
Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock...
s, pediment fans, colluvium
Colluvium
Colluvium is the name for loose bodies of sediment that have been deposited or built up at the bottom of a low-grade slope or against a barrier on that slope, transported by gravity. The deposits that collect at the foot of a steep slope or cliff are also known by the same name. Colluvium often...
, alluvium
Alluvium
Alluvium is loose, unconsolidated soil or sediments, eroded, deposited, and reshaped by water in some form in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel...
and coastal sands
Sands
-Buildings:*Sands Casino Resort Bethlehem, a newly-opened casino resort in Bethlehem, Pennsylvania*Sands Hotel, a closed hotel/casino in Las Vegas, Nevada**Sands Atlantic City, a closed hotel/casino in Atlantic City, New Jersey...
. Particularly, the Borra caves are stated to be one of the largest caves in the Indian subcontinent
Indian subcontinent
The Indian subcontinent, also Indian Subcontinent, Indo-Pak Subcontinent or South Asian Subcontinent is a region of the Asian continent on the Indian tectonic plate from the Hindu Kush or Hindu Koh, Himalayas and including the Kuen Lun and Karakoram ranges, forming a land mass which extends...
.
The caves, in the reserved forest area consisting of 14 villages inhabited by tribals, basically host a variety of speleothems ranging from very small to big and irregularly shaped stalactites and stalagmites. The carbonate
Carbonate
In chemistry, a carbonate is a salt of carbonic acid, characterized by the presence of the carbonate ion, . The name may also mean an ester of carbonic acid, an organic compound containing the carbonate group C2....
rocks are pure white
White
White is a color, the perception of which is evoked by light that stimulates all three types of color sensitive cone cells in the human eye in nearly equal amounts and with high brightness compared to the surroundings. A white visual stimulation will be void of hue and grayness.White light can be...
, and coarsely crystalline and the deformed and banded marbles
Marbles
A marble is a small spherical toy usually made from glass, clay, steel, or agate. These balls vary in size. Most commonly, they are about ½ inch in diameter, but they may range from less than ¼ inch to over 3 inches , while some art glass marbles fordisplay purposes are over 12 inches ...
cover a triangular area of 2 square kilometre; surrounded by Diopside
Diopside
Diopside is a monoclinic pyroxene mineral with composition MgCaSi2O6. It forms complete solid solution series with hedenbergite and augite, and partial solid solutions with orthopyroxene and pigeonite. It forms variably colored, but typically dull green crystals in the monoclinic prismatic class...
–scapolite
Scapolite
Scapolite , is a group of rock-forming silicate minerals composed of aluminium, calcium, and sodium silicate with chlorine, carbonate and sulfate.-Properties:...
–feldspar
Feldspar
Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....
calc-granulites. The pyroxenite
Pyroxenite
Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite and diopside, hypersthene, bronzite or enstatite. They are classified into clinopyroxenites, orthopyroxenites, and the websterites which contain both pyroxenes...
outcrops are dark and massive and include discontinuous calc-silicate bands, some of brown mica
Mica
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition...
and others with calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
.
The Gosthani River, which originates from these caves and flows between the solidified stalactites and stalagmites in the Karstic lime stones formation, is the cause for the development of the odd shapes of structures. Water percolating from the roof of the caves dissolve limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
and trickle drop by drop to form stalactite
Stalactite
A stalactite , "to drip", and meaning "that which drips") is a type of speleothem that hangs from the ceiling of limestone caves. It is a type of dripstone...
at the roof of the cave and then dripping down to the ground form stalagmite
Stalagmite
A stalagmite is a type of speleothem that rises from the floor of a limestone cave due to the dripping of mineralized solutions and the deposition of calcium carbonate. This stalagmite formation occurs only under certain pH conditions within the underground cavern. The corresponding formation on...
. (see picture). Stalactites are calcium carbonate
Calcium carbonate
Calcium carbonate is a chemical compound with the formula CaCO3. It is a common substance found in rocks in all parts of the world, and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. Calcium carbonate is the active ingredient in agricultural lime,...
deposits that hang from the top of the cave. Stalagmites are deposits that form at the bottom of the cave and grow upward. These deposits have developed into interesting forms and structures inside the caves such as Shiva
Shiva
Shiva is a major Hindu deity, and is the destroyer god or transformer among the Trimurti, the Hindu Trinity of the primary aspects of the divine. God Shiva is a yogi who has notice of everything that happens in the world and is the main aspect of life. Yet one with great power lives a life of a...
–Parvati
Parvati
Parvati is a Hindu goddess. Parvati is Shakti, the wife of Shiva and the gentle aspect of Mahadevi, the Great Goddess...
, Mother–Child, Rishi
Rishi
Rishi denotes the composers of Vedic hymns. However, according to post-Vedic tradition, the rishi is a "seer" to whom the Vedas were "originally revealed" through states of higher consciousness. The rishis were prominent when Vedic Hinduism took shape, as far back as some three thousand years...
’s beard, Human brain
Human brain
The human brain has the same general structure as the brains of other mammals, but is over three times larger than the brain of a typical mammal with an equivalent body size. Estimates for the number of neurons in the human brain range from 80 to 120 billion...
, mushrooms, crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...
, temple
Temple
A temple is a structure reserved for religious or spiritual activities, such as prayer and sacrifice, or analogous rites. A templum constituted a sacred precinct as defined by a priest, or augur. It has the same root as the word "template," a plan in preparation of the building that was marked out...
, church, etc. These shapes have captured the imagination of tourists, while some have been given religious interpretations.
The Caves are deep and totally aphotic. There is a twilight zone in the caves with limited light penetration. The Stalactites seen in the caves are about 0.1 m (0.328083989501312 ft) to 3.5 m (11.5 ft) in length while the Stalagmites are 1.2 m (3.9 ft) long and columns are 6 m (19.7 ft) in height and 0.75 m (2.5 ft) in width. The height of the cave is 12 m (39.4 ft) and the length is about 200 m (656.2 ft). The average temperature of the inner cave wall is reported to be about 16 °C (60.8 °F). Sulphur springs
Spring (hydrosphere)
A spring—also known as a rising or resurgence—is a component of the hydrosphere. Specifically, it is any natural situation where water flows to the surface of the earth from underground...
discharge into the cave passages causing corrosion
Corrosion
Corrosion is the disintegration of an engineered material into its constituent atoms due to chemical reactions with its surroundings. In the most common use of the word, this means electrochemical oxidation of metals in reaction with an oxidant such as oxygen...
of limestone. The spring waters display floating Mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
-like biofilms. These are thick orange microbial mats (2.5 cm (0.984251968503937 in)–3 cm (1.2 in) thick) with patches of yellow biofilms extending 3 m (9.8 ft) from the aphotic deep cave orifice.
While the caves are basically limestone formations, the area surrounding these are of mica
Mica
The mica group of sheet silicate minerals includes several closely related materials having highly perfect basal cleavage. All are monoclinic, with a tendency towards pseudohexagonal crystals, and are similar in chemical composition...
formations which are prospected for precious stones like rubies.
The geological features of these caves are stated to be found only in Borra in India. Archeological artifacts
Artifact (archaeology)
An artifact or artefact is "something made or given shape by man, such as a tool or a work of art, esp an object of archaeological interest"...
(Paleolithic
Paleolithic
The Paleolithic Age, Era or Period, is a prehistoric period of human history distinguished by the development of the most primitive stone tools discovered , and covers roughly 99% of human technological prehistory...
implements) have been found in the caves. The excavations carried out in the caves by the Archeologists of the Andhra University, have unearthed stone tools of middle Paleolithic culture dating back to 30,000 to 50,000 years, which confirm human habitation.
Genesis
SpeleothemSpeleothem
A speleothem , commonly known as a cave formation, is a secondary mineral deposit formed in a cave. Speleothems are typically formed in limestone or dolostone solutional caves.-Origin and composition:...
carbonates (considered as inorganic precipitates) found in the caves have been subject to scientific studies. In fluviatile, spring, cave and soil environments Microbial carbonates are important. In the biofilms and/or microbial mats, which are formed in the caves, the principal organisms associated are bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, particularly cyanobacteria, small algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
and fungi. Petrographic analysis of a thin section has uncovered the presence of lithified structures and micrite
Micrite
Micrite is a limestone constituent formed of calcareous particles ranging in diameter up to 4 μm formed by the recrystallization of lime mud.The term was coined in 1959 by Robert Folk for his carbonate rock classification system...
, present as laminated to clotted with chocolate-brown blebs. These are identical to microbialites observed in modern and ancient stromatolitic carbonates. Laboratory observations with Scanning Electron Microscope (SEM) have also confirmed the presence of calcified bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, micro-rods, and needle calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
. Organic mats (yellow-orange in colour) comprise of mineralized filamentous bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
, bacterial stalks, cells
Cell (biology)
The cell is the basic structural and functional unit of all known living organisms. It is the smallest unit of life that is classified as a living thing, and is often called the building block of life. The Alberts text discusses how the "cellular building blocks" move to shape developing embryos....
and sheaths. Thus, these studies have indicated that biological (microorganisms) have actively influenced in the genesis of speleothem carbonates of the Borra Caves.
Microorganisms
The effect of microorganisms in the mats on the cave formation and their role on iron mineral precipitation has been further studied. A report by Sushmitha Baskar et. al indicates a link between iron–rich mats formation and iron precipitating bacteriaThe abstract of their report states:
The spring waters (pH neutral 7.5–7.7) contained dissolved metals like iron and the organic mat sludge (pHPHIn chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
7.0–7.3) had a TOCTotal organic carbonTotal organic carbon is the amount of carbon bound in an organic compound and is often used as a non-specific indicator of water quality or cleanliness of pharmaceutical manufacturing equipment....
content of approximately 5.4 wt%. Geochemically, the spring waters deep below the microbial mats contained FeIronIron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
369 ppb, SrStrontiumStrontium is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when exposed to air. It occurs naturally in the minerals celestine and...
198 ppb; and the organic mat sludge contained MgMagnesiumMagnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
9 ppm, Fe 427 ppb, ZnZincZinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
149 ppb, Sr 190 ppb. XRD observations displayed Fe minerals (dominantly hematiteHematiteHematite, also spelled as haematite, is the mineral form of iron oxide , one of several iron oxides. Hematite crystallizes in the rhombohedral system, and it has the same crystal structure as ilmenite and corundum...
), minor amounts of zincZincZinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
galliumGalliumGallium is a chemical element that has the symbol Ga and atomic number 31. Elemental gallium does not occur in nature, but as the gallium salt in trace amounts in bauxite and zinc ores. A soft silvery metallic poor metal, elemental gallium is a brittle solid at low temperatures. As it liquefies...
sulfideSulfideA sulfide is an anion of sulfur in its lowest oxidation state of 2-. Sulfide is also a slightly archaic term for thioethers, a common type of organosulfur compound that are well known for their bad odors.- Properties :...
and nitrofuryl compounds. At least four groups of bacteria identified by direct microscopyMicroscopyMicroscopy is the technical field of using microscopes to view samples and objects that cannot be seen with the unaided eye...
and SEM-EDX on the basis of morphologyMorphology (biology)In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
could be observed in all samples: Leptothrix–like organisms, entombed bacterial mineral sheaths, a few stalks of Gallionella–like organisms and some additional bacteria that could not be further identified. Leptothrix–like organisms contained 43.22–60.08 wt % Fe and the mineral precipitated near and around these bacteriaBacteriaBacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
(in the actual unaltered samples on site) contained 30.76–45.22 wt% Fe as identified and quantified by SEM-EDX.
Fauna and flora
The faunaFauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...
observed in the caves are predominantly bats, as well as the golden gecko
Gecko
Geckos are lizards belonging to the infraorder Gekkota, found in warm climates throughout the world. They range from 1.6 cm to 60 cm....
. The type of bat reported is the fulvous fruit bat (Rousettus leschenaultii) – a species which roosts in large caves, old buildings, dungeons and dark areas of old forts. This species has short and slender musculature with large, well developed eyes. They feed on flowers and fruits, particularly jamun, guava
Guava
Guavas are plants in the myrtle family genus Psidium , which contains about 100 species of tropical shrubs and small trees. They are native to Mexico, Central America, and northern South America...
, silk
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity...
, cotton
Cotton
Cotton is a soft, fluffy staple fiber that grows in a boll, or protective capsule, around the seeds of cotton plants of the genus Gossypium. The fiber is almost pure cellulose. The botanical purpose of cotton fiber is to aid in seed dispersal....
and mango
Mango
The mango is a fleshy stone fruit belonging to the genus Mangifera, consisting of numerous tropical fruiting trees in the flowering plant family Anacardiaceae. The mango is native to India from where it spread all over the world. It is also the most cultivated fruit of the tropical world. While...
.
The forests in the area are of semi-evergreen deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...
type. The flora in the cave consist of mosses and brown-to-green algae
Algae
Algae are a large and diverse group of simple, typically autotrophic organisms, ranging from unicellular to multicellular forms, such as the giant kelps that grow to 65 meters in length. They are photosynthetic like plants, and "simple" because their tissues are not organized into the many...
. Since many of the species found are endangered, mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
operations are considered to be in violation of the Environmental Protection Act.
Access
The caves are well connected by roadRoad
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
, rail
Rail transport
Rail transport is a means of conveyance of passengers and goods by way of wheeled vehicles running on rail tracks. In contrast to road transport, where vehicles merely run on a prepared surface, rail vehicles are also directionally guided by the tracks they run on...
and air services. Vishkapatnam, the nearest airport
Airport
An airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
and the district headquarters, is 90 km (55.9 mi) by road, which is mostly a hill road and the journey takes about 3 hours.
Train services operate on the Kothavalasa
Kothavalasa
Kotha-valasa or Kotta-valasa is a census town and mandal in Vizianagaram district in the Indian state of Andhra Pradesh.-Geography:Kothavalasa is located at . It has an average elevation of 209 meters .-Demographics:...
-Kirandul
Kirandul
Kirandul is a city and a municipality in the Dantewada district in the Indian state of Chhattisgarh.It is a small town with NMDC colony, bus stand, railway station,Government Hospital and a college. Kirandul used to have a satellite township called Kailashnagar.-Demographics: India census, Kirandul...
railway line in East Coast Railway
East Coast Railway
The East Coast Railway is one of the sixteen railway zones of Indian Railways came into existence from 1 April 2003.The geographical jurisdiction of this railway zone extends over three states encompressing almost all parts of Orissa along with parts of Srikakulam, Vizainagaram and Visakhapatnam...
, Indian Railways
Indian Railways
Indian Railways , abbreviated as IR , is a departmental undertaking of Government of India, which owns and operates most of India's rail transport. It is overseen by the Ministry of Railways of the Government of India....
. The train journey over a distance of 100 km (62.1 mi)from the Vishkapatanam Rly station passes through Eastern Ghats (hill) section), which has 30 tunnels en-route. The journey by train takes about 5 hours to the Railway Station near the caves called the ‘Borra Guhalu Railway station’.
Visitor information
Guided tours for a day trip to the Borra Caves cover interesting attractions like the Tyada Railway Tunnel, Damuku View Point, Ananthagiri CoffeeCoffee
Coffee is a brewed beverage with a dark,init brooo acidic flavor prepared from the roasted seeds of the coffee plant, colloquially called coffee beans. The beans are found in coffee cherries, which grow on trees cultivated in over 70 countries, primarily in equatorial Latin America, Southeast Asia,...
Plantation
Plantation
A plantation is a long artificially established forest, farm or estate, where crops are grown for sale, often in distant markets rather than for local on-site consumption...
, Padmapuram Gardens and the Araku Valley. For the benefit of the visitors, an information board at the entry point to the caves gives some details of the caves and its surroundings (pictured).
An Arraku and Borra rail-cum-road package tour organized by the Andhra Pradesh State Tourism Department is available for visitors keen to see the Borra caves.
Flora
Flora is the plant life occurring in a particular region or time, generally the naturally occurring or indigenous—native plant life. The corresponding term for animals is fauna.-Etymology:...
and fauna
Fauna
Fauna or faunæ is all of the animal life of any particular region or time. The corresponding term for plants is flora.Zoologists and paleontologists use fauna to refer to a typical collection of animals found in a specific time or place, e.g. the "Sonoran Desert fauna" or the "Burgess shale fauna"...
. The Andhra Pradesh State Tourism Department has installed 26 mercury
Mercury (element)
Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...
, sodium vapor and halogen
Halogen
The halogens or halogen elements are a series of nonmetal elements from Group 17 IUPAC Style of the periodic table, comprising fluorine , chlorine , bromine , iodine , and astatine...
electric lamps, which provide beautiful views of the formations (pictured). Geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...
s and tourists visiting the caves are enchanted by the lighted caves. The Araku valley, a famous hill station, about 29 km (18 mi) from the Borra caves is also an interesting tourist attraction for people visiting the caves.
November and December are ideal months to visit the caves. The caves are open to visitors from 10 am to 5:30 pm.
External links
- cave-biology.org Cave biology (biospeleology) in India.
- Borra Caves photographs, 2011