Located inside the Lalbagh Botanical Garden lies one of the oldest geological locations in Peninsular Gneiss.
Lalbagh established by Hyder Ali based on Mughal Gardens at Sira is not only a famous botanical garden but has also a historical link. The creation of the Bengaluru city in the 16th century is attributed to Kempegowda, the then feudal leader under the feudatory of the Vijayanagara empire, who established four cardinal towers setting limits to the growth of the city. One of the towers at the southern end of the city is the Lalbagh tower erected over the Lalbagh hill which is made up of Peninsular Gneiss, now identified as a National Geological Monument. The city has outgrown the limits set by Kempegowda many times and is now part of the downtown area.The topographic setting of the Lalbagh rock, from a layman's interest, is that in the western and northern directions it slopes steeply while it merges gently with soil in the east and south. View from the North is impressive since the rock has retained its original form. The west or north–west view is panoramic and aesthetic, with grayish–white clean plates like appearance. The rock shines white after the rains and attracts attention of the visitors who excitedly climb the rock mass to the tower at the top to get a panoramic view of the gardens and the city.
The Archean gneisses and schists, which are the oldest rocks of the Indian Shield, constitute a considerable area of Peninsular India. The Dharwar (Super Group) and the Peninsular Gneissic Complex are the classified groups of the Precambrian rocks of India. The extent of the Archean system is depicted as the dominant system of South India. In most stratigraphic schemes, the peninsular gneisses are shown as the younger Archaean strata situated above the Sargur Group. Granitization of the older sedimentary–volcogenic sequence are reported as sources of the peninsular gneisses made up of polyphase migmatites, gneisses and granites ranging in composition from granodiorite to tonalite. The rocks of the Dharwar Group, which are mainly sedimentary in origin, occur in narrow elongated synclines resting on the gneisses found in Bellary district, Mysore and the Aravallis of Rajputana. The supracrustal rocks of the Dharwar Group of the southern Indian Peninsula, as depicted in the geological map of South India, have the Peninsular Gneiss as the basement rock formation, also stated to be the remobilized basement. Migmatization of pre-existing metasedimentary and meta–igneous rocks are considered the contributors to formation of the composite gneiss.
To be able to log this earth cache please send the answers to the following questions:
1) What is the colour of the amphibolite present?
2)During formation the veins appeared in the surface, how wide are these veins?
3)There are also a different type of vein that is smaller why do you think these are the size they are?
4)Attached a photo with your geocaching name or self in your log or message with the monument in the backgorund
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