Tirupati Eparchaean Unconformity | |
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Geological monument | |
Coordinates: 13°41′00″N79°21′00″E / 13.6833°N 79.35°E | |
Location | Tirupati, India |
Website | www |
Tirupati Eparchaean Unconformity, a notified National Geo-heritage Monument [1] [2] [3] is a major discontinuity of stratigraphic 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 – Tirumala Ghat road in Tirupati district of Andhra Pradesh, India. [4] [5]
In 2001, the Geological Survey of India (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, the paleoenvironment and the exotic collection of paleo-flora and fauna. The details provided for the Eparchaean Unconformity monument indicate that this feature forms the boundary surface between Proterozoic Nagari Quartzites and Archaean granite. The time gap between the formation of the two units is at least 500 Ma. [5]
At this location, the boundary is between sedimentary rocks of the Cudappah Supergroup, 1600 million years in age, and Archaean rocks comprising granites, gneisses and dolerite 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. [5]
The geological monument is located in the Tirupati valley, which is bounded between ( 13°30′00″N79°22′30″E / 13.50°N 79.375°E ) and ( 13°27′N79°45′E / 13.45°N 79.75°E ). The basin is delimited between the Palakonda-Velikonda and Sanambatla-Srikalahasti and Nagari ranges of the Eastern Ghats. Tirupati Temple, the most famous pilgrimage centre in South India is in the midst of the range of hills. The hills enclose the temple town to give it a form of an amphitheatre setting. [6]
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:
The Tirumala hills essentially of precambrian period are composed of sedimentary rocks – quartzites and intercalated shales, 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. [5] [6] [8]
The hill ranges of the Tirumala rise to a height of 900 metres (3,000 ft) (at Tirumala) from the average height of 150 metres (490 ft) in the plains at Tirupati. The steep scarp of the ranges shows the Eparchian Unconformity's topographic, structural and denudational features. [5] [9] The sedimentary thickness of the Cudappah basin is of the order of 12 kilometres (7.5 mi), and includes volcanic sequences in the form of sills and dykes. A prominent Eparchaean Unconformity of the formation resting on the archaean peninsular gneissic complex is noted. Rocks of the Cuddapah Supergroup, and the overlying Kurnool 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. [5] [10]
The location of the Geological Monument is well connected by road, rail and air routes. The nearest railhead to Tirumala hills is Tirupati. The geological monument is located 10 kilometres (6.2 mi) northwest of Tirupati town, at the 12 kilometres (7.5 mi) point on the Tirupati – Tirumala Ghat road. From Tirupati railway station the approach to the Tirumala temple is only by road, a distance of 10 kilometres (6.2 mi). [5] [11] The nearest airport is located at Renigunta, in Tirupati city, which connects to Chennai, Hyderabad and Bangalore airports. Regular bus services (both private and government) are operated by all the states bordering Andhra Pradesh. [4] [5] [12]
Tirumala is a spiritual town in Tirupati district of the Indian state of Andhra Pradesh. It is one of the suburbs of the Tirupati urban agglomeration. The town is a part of Tirupati Urban Development Authority and located in Tirupati (urban) mandal of Tirupati revenue division. It is a hill town where Tirumala Venkateshvara Temple is located, a popular shrine of Vishnu. The town is strictly vegetarian.
The Eastern Ghats are a discontinuous range of mountains along India's eastern coast. The Eastern Ghats pass through the states of Odisha and Andhra Pradesh in the north to Tamil Nadu in the south, passing parts of Karnataka and Telangana on the way. They are eroded and cut through by four major rivers of peninsular India, viz., the Mahanadi, Godavari, Krishna and Kaveri. Jindhagada, or Seethamma Konda, is the highest point in both Andhra Pradesh and the Eastern Ghats, at 1,690 metres (5,540 ft). The Biligiriranga Hills in Karnataka are the tallest hill range in the Eastern Ghats, with many peaks above 1500 m in height.
The Aravalli Range is a mountain range in Northern-Western India, running approximately 670 km (420 mi) in a south-west direction, starting near Delhi, passing through southern Haryana, Rajasthan, and ending in Ahmedabad Gujarat. The highest peak is Guru Shikhar on Mount Abu at 1,722 m (5,650 ft). The Aravalli Range is arguably the oldest geological feature on Earth, having its origin in the Proterozoic era.
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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 Venkateshwara Temple and other historic temples. It is located at a distance of 150 km from Chennai, 250 km from Bangalore,406 km from Amaravati. It is one of the eight Svayam vyakta kshetras dedicated to Vishnu. Tirupati is a municipal corporation and the headquarters of Tirupati (urban) mandal, Tirupati (rural) mandal, and the Tirupati revenue division.
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Natural Arch, Tirumala hills, a notified National Geo-heritage Monument, is a distinctive geological feature 1 km (0.6 mi) north of the Tirumala hills temple, near the Chakra Teertham in Tirupati district in the state of Andhra Pradesh, India. The arch is also called Silathoranam (శిలాతోరణం) in the local language. The arch measures 8 m (26.2 ft) in width and 3 m (9.8 ft) in height, and is naturally formed in the quartzites of Cuddapah Supergroup of Middle to Upper Proterozoic due to natural erosive forces.
Peninsular Gneiss or Peninsular Gniessic Complex are the gneissic complex of the metamorphics found all over the Indian Peninsula, on top of which, the supra-crustal Dharwar System have been laid down. The term was first fashioned by W.F.Smeeth of the Mysore Geological Department in 1916 based on the first scientific study of this rock exposure. One of the best exposures of this rock mass, dated 2.5 to 3.4 billion years, is located at Lal Bagh in Bangalore. The exposure is also called the Lalbagh rock.
The Cardenas Basalt, also known as either the Cardenas Lava or Cardenas Lavas, is a rock formation that outcrops over an area of about 310 km2 (120 mi2) in the eastern Grand Canyon, Coconino County, Arizona. The lower part of the Cardenas Basalt forms granular talus slopes. Its upper part forms nearly continuous low cliffs that are parallel to the general course of the Colorado River. The most complete, readily accessible, and easily studied exposure of the Cardenas Basalt lies in Basalt Canyon. This is also its type locality.
The Unkar Group is a sequence of strata of Proterozoic age that are subdivided into five geologic formations and exposed within the Grand Canyon, Arizona, Southwestern United States. The 5-unit Unkar Group is the basal member of the 8-member Grand Canyon Supergroup. The Unkar is about 1,600 to 2,200 m thick and composed, in ascending order, of the Bass Formation, Hakatai Shale, Shinumo Quartzite, Dox Formation, and Cardenas Basalt. Units 4 & 5 are found mostly in the eastern region of Grand Canyon. Units 1 through 3 are found in central Grand Canyon. The Unkar Group accumulated approximately between 1250 and 1104 Ma. In ascending order, the Unkar Group is overlain by the Nankoweap Formation, about 113 to 150 m thick; the Chuar Group, about 1,900 m (6,200 ft) thick; and the Sixtymile Formation, about 60 m (200 ft) thick. These are all of the units of the Grand Canyon Supergroup. The Unkar Group makes up approximately half of the thickness of the 8-unit Supergroup.
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