Tirupati Eparchaean Unconformity, a notified National Geo-heritage MonumentGeo-Heritage Sites, Minister of Mines Press release, 09-March-2016
/ref>national geo-heritage of India

INTACH The Indian National Trust for Art and Cultural Heritage (INTACH) is a non-profit charitable organisation registered under the Societies Registration Act, 1860. In 2007, the United Nations awarded INTACH a special consultative status with Unite ...

is a major discontinuity of

stratigraphic Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...

significance that represents a period of remarkable serenity in the geological history of the earth i.e. sudden changes and discontinuity in the rock layers in earth's crust. It is seen at the steep natural slopes, road scars and ravines in the

Tirupati Tirupati () is a city in the Indian state of Andhra Pradesh. It is the administrative headquarters of the Tirupati district. The city is home to the important Hindu shrine of Tirumala Venkateswara Temple and other historic temples and is refe ...

–

Tirumala Tirumala is a spiritual town in Tirupati district of the Indian state of Andhra Pradesh. It is one of the suburbs of the Tirupati, Tirupati urban agglomeration. The town is a part of Tirupati Urban Development Authority and located in Tirupa ...

Ghat Ghat, a term used in the Indian subcontinent, depending on the context could refer either to a range of stepped hills with valleys (ghati in Hindi), such as the Eastern Ghats and Western Ghats; or the series of steps leading down to a body of ...

road A road is a linear way for the conveyance of traffic that mostly has an improved surface for use by vehicles (motorized and non-motorized) and pedestrians. Unlike streets, the main function of roads is transportation. There are many types of ...

Tirupati district Tirupati district () is one of the twenty-six districts in the Indian state of Andhra Pradesh and one of the eight districts in the Rayalaseema region of the Andhra Pradesh state. The district headquarters is located at Tirupati city. Tirupat ...

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 ...

, India. In 2001, the

Geological Survey of India The Geological Survey of India (GSI) is a scientific agency of India. It was founded in 1851, as a Government of India organization under the Ministry of Mines, one of the oldest of such organisations in the world and the second oldest survey ...

(GSI) declared the unconformity to be one of the 26 "Geological Monuments of India". GSI's commemoration document, published on the occasion of the 150 years anniversary celebration, provides an insight into the formation of the subcontinent, the

orogeny Orogeny is a mountain building process. An orogeny is an event that takes place at a convergent plate margin when plate motion compresses the margin. An ''orogenic belt'' or ''orogen'' develops as the compressed plate crumples and is uplifted t ...

, the

paleoenvironment Paleoecology (also spelled palaeoecology) is the study of interactions between organisms and/or interactions between organisms and their environments across geologic timescales. As a discipline, paleoecology interacts with, depends on and informs ...

and the exotic collection of paleo-

flora Flora is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referred to as flora, as in the terms '' gut flora'' or '' skin flora''. E ...

and

fauna Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is ''flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. Zoo ...

. The details provided for the Eparchaean Unconformity monument indicate that this feature forms the boundary surface between

Proterozoic The Proterozoic () is a geological eon spanning the time interval from 2500 to 538.8million years ago. It is the most recent part of the Precambrian "supereon". It is also the longest eon of the Earth's geologic time scale, and it is subdivided ...

Nagari Quartzites and Archaean granite. The time gap between the formation of the two units is at least 500 Ma. At this location, the boundary is between sedimentary rocks of the Cudappah Supergroup, 1600 million years in age, and Archaean rocks comprising

granites Granite () is a coarse-grained ( phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

gneisses 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 ...

and

dolerite Diabase (), also called dolerite () or microgabbro, is a mafic, holocrystalline, subvolcanic rock equivalent to volcanic basalt or plutonic gabbro. Diabase dikes and sills are typically shallow intrusive bodies and often exhibit fine-grained ...

dykes that are more than 2100 million years old. This unconformity gives an indication of the enormous time gap in the creation of the earth's crust.

Topography

The geological monument is located in the Tirupati valley, which is bounded between () and (). The basin is delimited between the

Palakonda Palakonda is a town in Parvathipuram Manyam district of the Indian state of Andhra Pradesh. It is a nagar panchayat and the mandal headquarters of Palakonda mandal in Palakonda revenue division Geography Palakonda is located at . It has an a ...

- Velikonda and Sanambatla-

Srikalahasti Srikalahasti is a holy town in Tirupati district of the Indian state of Andhra Pradesh. It is a municipality and the revenue division of Srikalahasti mandal & Srikalahasti revenue division. It is a part of Tirupati Urban Development Authority, wh ...

and Nagari ranges of 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 ...

Tirupati Temple Sri Venkateswara Swami Vaari Temple is a Hindu temple situated in the hill town of Tirumala at Tirupati in Tirupati district of Andhra Pradesh, India. The Temple is dedicated to Venkateswara, a form of Vishnu, who is believed to have appeared ...

, the most famous pilgrimage centre in

South India South India, also known as Dakshina Bharata or Peninsular India, consists of the peninsular southern part of India. It encompasses the Indian states of Andhra Pradesh, Karnataka, Kerala, Tamil Nadu, and Telangana, as well as the union territo ...

is in the midst of the range of hills. The hills enclose the temple town to give it a form of an amphitheatre setting.

Geology

Plaque at Tirumal hills on Eparchean Unconformity

The Tirupati hills are situated at the foot of a range of hills known by several names, including 'Seshachala', 'Venkatachala' and 'Balaji'. There are four geological units: :(1) Archaean rocks of the eastern Dharwar Craton (the granites and gneisses) :(2) the Eparchean unconformity (Quartzose sandstones overlying the granite with a distinct unconformity) :(3) Puranas (a general name for Proterozoic sedimentary sequences found in a series of basins deposited on the Indian Shield; including the Cuddapah Basin) :(4) Quaternary deposits The Tirumala hills essentially of

precambrian The Precambrian (or Pre-Cambrian, sometimes abbreviated pꞒ, or Cryptozoic) is the earliest part of Earth's history, set before the current Phanerozoic Eon. The Precambrian is so named because it preceded the Cambrian, the first period of the ...

period are composed of

sedimentary rocks Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles t ...

–

quartzites Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to ...

and intercalated

shales Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especiall ...

, which are referred to as the Nagari quartzites, which forms part of the Cuddapah Supergroup. It is a subset of the Purana rock succession that rests above the archaean rocks. The hill ranges of the Tirumala rise to a height of (at Tirumala) from the average height of in the plains at Tirupati. The steep scarp of the ranges shows the Eparchian Unconformity's topographic, structural and denudational features. The sedimentary thickness of the Cudappah basin is of the order of , and includes

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

sequences in the form of sills and dykes. A prominent Eparchaean Unconformity of the formation resting on the archaean

peninsular A peninsula (; ) is a landform that extends from a mainland and is surrounded by water on most, but not all of its borders. A peninsula is also sometimes defined as a piece of land bordered by water on three of its sides. Peninsulas exist on all ...

gneissic complex is noted. Rocks of the Cuddapah Supergroup, and the overlying

Kurnool Kurnool is a city in the state of Andhra Pradesh, India. It formerly served as the capital of Andhra State (1953–1956). The city is often referred to as "The Gateway of Rayalaseema".Kurnool is also known as The City of Gem Stones. It also se ...

Group, comprise the stratigraphic sequence of the basin. This feature is contiguous all along the defined Archaean-Cuddapah contact zone even though its age may vary along its traced path.

Access

The location of the Geological Monument is well connected by road, rail and air routes. The nearest railhead to Tirumala hills is

. The geological monument is located northwest of Tirupati town, at the point on the Tirupati – Tirumala Ghat road. From Tirupati railway station the approach to the Tirumala temple is only by road, a distance of . The nearest airport is located at

Renigunta Renigunta is a neighbourhood and suburb of Tirupati located in Tirupati district of the Indian state of Andhra Pradesh. Tirupati Airport is located in Renigunta. It is a part of Tirupati urban agglomeration. It is also the mandal headquarters of ...

, in

city, which connects to

Chennai Chennai (, ), formerly known as Madras ( the official name until 1996), is the capital city of Tamil Nadu, the southernmost Indian state. The largest city of the state in area and population, Chennai is located on the Coromandel Coast of th ...

Hyderabad Hyderabad ( ; , ) is the capital and largest city of the Indian state of Telangana and the ''de jure'' capital of Andhra Pradesh. It occupies on the Deccan Plateau along the banks of the Musi River (India), Musi River, in the northern part ...

and

Bangalore Bangalore (), officially Bengaluru (), is the capital and largest city of the Indian state of Karnataka. It has a population of more than and a metropolitan population of around , making it the third most populous city and fifth most ...

airports. Regular bus services (both private and government) are operated by all the states bordering Andhra Pradesh.

Gallery

File:Detrital rocks of Tirumala Hills Ghatroad Tirupati.JPG File:Sandstone of detrital quartz rocks at Kapilatheertham Tirupati.JPG File:Garuda cliff in Tirumala.jpg

References

{{Andhra Pradesh, collapsed=true National Geological Monuments in India Geology of Andhra Pradesh Tirupati Tirupati district Geography of Tirupati district