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 the ...

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: lithost ...

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 States and territories of India, state of Andhra Pradesh and serves as the administrative headquarters of Tirupati district. It is known for its significant religious and cultural heritage, being home to th ...

–

Tirumala Tirumala is a Hindu religious temple town in Tirupati district of the Indian state of Andhra Pradesh. It is one of the neighbourhoods of the Tirupati city. The town is a part of Tirupati Urban Development Authority and located in Tirupat ...

Ghat Ghat (), a term used in the Indian subcontinent, to refer to the series of steps leading down to a body of water or wharf, such as a bathing or cremation place along the banks of a river or pond, the Ghats in Varanasi, Dhobi Ghat or the Aap ...

road A road is a thoroughfare used primarily for movement of traffic. Roads differ from streets, whose primary use is local access. They also differ from stroads, which combine the features of streets and roads. Most modern roads are paved. Th ...

Tirupati district Tirupati district () is one of the eight districts of Rayalaseema region in the Indian state of Andhra Pradesh.The district headquarters is located at Tirupati city. This district is known for its numerous historic temples, including the Hindu ...

Andhra Pradesh Andhra Pradesh (ISO 15919, ISO: , , AP) is a States and union territories of India, state on the East Coast of India, east coast of southern India. It is the List of states and union territories of India by area, seventh-largest state and th ...

, 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-mountain formation, building process that takes place at a convergent boundary, convergent plate margin when plate motion compresses the margin. An or develops as the compressed plate crumples and is tectonic uplift, u ...

, 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 (: floras or florae) is all the plant life present in a particular region or time, generally the naturally occurring (indigenous (ecology), indigenous) native plant, native plants. The corresponding term for animals is ''fauna'', and for f ...

and

fauna Fauna (: faunae or faunas) is all of the animal life present in a particular region or time. The corresponding terms for plants and fungi are ''flora'' and '' funga'', respectively. Flora, fauna, funga and other forms of life are collectively ...

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

Proterozoic The Proterozoic ( ) is the third of the four geologic eons of Earth's history, spanning the time interval from 2500 to 538.8 Mya, and is the longest eon of Earth's geologic time scale. It is preceded by the Archean and followed by the Phanerozo ...

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 under ...

gneisses Gneiss (pronounced ) 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. This rock is formed under p ...

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-grain ...

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 ...

- Velikonda and Sanambatla-

Srikalahasti Srikalahasti is a town in Tirupati district located in the Indian state of Andhra Pradesh. It is a municipality and the revenue division of Srikalahasti mandal and Srikalahasti revenue division. It is a part of the Tirupati Urban Development Au ...

and Nagari ranges of the

Eastern Ghats The Eastern Ghats is a mountain range that stretches along the East Coast of India, eastern coast of the Indian peninsula. Covering an area of , it traverses the states and union territories of India, states of Odisha, Telangana, Andhra Prade ...

Tirupati Temple The Venkateswara Temple of Tirumala or Sri Venkateswara Swami Temple is a Hindu temple situated in the hills of Tirumala, Tirupati Urban mandal, Tirupati Urban Mandal in the Tirupati district of Andhra Pradesh, India. The temple is dedicated t ...

, the most famous pilgrimage centre in

South India South India, also known as Southern India or Peninsular India, is the southern part of the Deccan Peninsula in India encompassing the states of Andhra Pradesh, Karnataka, Kerala, Tamil Nadu and Telangana as well as the union territories of ...

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 pC, 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 t ...

period are composed of

sedimentary rocks Sedimentary rocks are types of rock formed by the cementation of sediments—i.e. particles made of minerals (geological detritus) or organic matter (biological detritus)—that have been accumulated or deposited at Earth's surface. Sedim ...

–

quartzites Quartzite is a hard, non- foliated metamorphic rock that 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 tectoni ...

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, especial ...

, 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 commonly defined as a vent or fissure 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 fo ...

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 only connected to land on one side. Peninsulas exist on each continent. The largest peninsula in the world is the Arabian Peninsula. Etymology The word ''peninsula'' derives , . ...

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 famous for Diamond hunting as diamonds ca ...

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 suburb and outgrowth of Tirupati located in Tirupati district of the Indian state of Andhra Pradesh. It is a part of Tirupati urban agglomeration. Tirupati Airport is located in Renigunta. It is also one of the mandals in Tirupa ...

, in

city, which connects to

Chennai Chennai, also known as Madras (List of renamed places in India#Tamil Nadu, its official name until 1996), is the capital city, capital and List of cities in Tamil Nadu by population, largest city of Tamil Nadu, the southernmost states and ...

Hyderabad Hyderabad is the capital and largest city of the Indian state of Telangana. It occupies on the Deccan Plateau along the banks of the Musi River (India), Musi River, in the northern part of Southern India. With an average altitude of , much ...

and

Bangalore Bengaluru, also known as Bangalore (List of renamed places in India#Karnataka, its official name until 1 November 2014), is the Capital city, capital and largest city of the southern States and union territories of India, Indian state of Kar ...

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