T201 Cultural Geology and Heritage Stone: Use, Petrology, Quarrying, Engineering Properties, and Other Aspects of Stone Used for Buildings, Monuments, Sculpture, or Otherwise Relating to the Interface of Stone with Human Culture Past and Present

Tuesday, 6 November 2018
1:30 PM - 5:30 PM
Room 133

CHARNOCKITE: IMPORTANT HERITAGE STONE FROM INDIA

Paper number: T201-4
Program: Technical Sessions
Time: 2:15 PM – 2:30 PM

Authors

Abstract

Charnockite is a granitic rock that has a special place in the cultural and geological heritage of India. It is a stone having an igneous or metamorphic origin which, in addition to quartz and feldspar, typically contains orthopyroxenes mostly in the form of hypersthene. It is also characterized by an attractive dark green colour and greasy lustre.

Charnockite was first named by T.H. Holland in 1893 to honor Job Charnock (1630-1693) who is credited with the founding of the city of Kolkata in 1686. The tombstone of Job Charnock, in St. John’s Church in Kolkata, is a charnockite sourced from St. Thomas Mount, at Pallavaram, a suburb of Chennai in Tamil Nadu State, India. Subsequently, in 1975, the Geological Survey of India declared the type locality of charnockite at St. Thomas Mount as a National Geological Monument.

The use of charnockite, for monuments as well as for construction and architectural use, is much older than the name and its use extends back more than 1000 years. Indian Charnockite has a cultural significance and utilisation that is greater than charnockite from other countries.

Most notably, a group of monuments at Mahabalipuram in Tamil Nadu built by Pallava kings in the 7th and 8th centuries have been carved out of charnockite and granite exposed along the Coromandal Coast of India, about 60 km south of Chennai. This temple town has about forty monuments including the largest open-air rock relief in the world. The rock-cut monuments are now recognized as a UNESCO World Heritage site. In general, Indian Charnockite has also been used widely in sculptures and the superstructure of several temples in India as well as in monuments overseas.A recent international sculpture that records the usage of Indian Charnockite is the Oscar Wilde memorial monument in Dublin, Ireland, constructed in 1997.

Given that charnockite was first identified in India and was named after an important historical figure, and has widespread usage and application in many heritage buildings in India, the rock is here suggested as a potential Global Heritage Stone Resource from India. The rock continues to be actively quarried today in southern India and is exported worldwide.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-316739

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