ARTICLE : 3 :
A Geo-Topography study of mineral belt of Bojjannakonda region
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A Geo-Topography study of mineral belt of Bojjannakonda region
(Visakhapatnam District, Andhra Pradesh)
by
Shri Tenneti Venkata Rao (Diploma in Mining Engineering, Govt.Mining Institute, Kotthagudem) C4 Chaitanya Apartments, 50-57-21/19, Rajendra Nagar, Dwaraka Nagar, Visakhapatnam, Andhra Pradesh.
Shri Tenneti Venkata Rao (Diploma in Mining Engineering, Govt.Mining Institute, Kotthagudem) C4 Chaitanya Apartments, 50-57-21/19, Rajendra Nagar, Dwaraka Nagar, Visakhapatnam, Andhra Pradesh.
The author by way of his vast experience in Mining and related exploration, and analysis of rocks and soils has taken up the geotopography study of the belt of Bojjannakonda region, situated about 2 Km from the town of Anakapalli city, in Andhra Pradesh which yielded some significant features of this region. The site is of ancient heritage of both Hindus and later of Buddhists with some sedimentary rocks derived from pre-existing rocks. It’s found that they are mechanically formed as fragmental or clastic rocks of sandstone and clay rocks. The remains of organically formed limestone rocks and carbonaceous or coaly rocks have been identified in present study. Soft stone property that allowed the carving of innumerable stupas and a Palace of Fourteen pillared Buddhist Shrine with Pali script inscriptions, imposing Meditating Buddha, The Ashoka Pillar and The Ganesh figure has been surmised to identify the ancient prevalent culture and civilization of this region. The samples collected and examined of the pre-kondalite with a quartzite rich constituent showed garnets as significant. The naturally occurring Garnets led to the understanding of the bedded or layered arrangements of outcrop and protuberance.
Keywords: rocks, garnets, Ganesh figure, pre-kondalite,Ashoka Pillar,Lingalagutta, Anakapalli,Almandine, Molten material, Earth's core, quarzite rich,Buddha Figure, Pali script
Introduction:
Sedimentary rocks derived from pre-existing rocks were deposited in beds or layers in this region. The aqueous rocks that were laid down in water are found to be an important feature of the Bojjannakonda region. The ancient Sarada River that flows even to-date has changed its course, may be several times with geological formations. The sandstone rocks are also known as Arenaciuos while the clay rocks as argillaceous rocks. The possible existence of Calcareous i.e. limestone rocks and the Coaly or Carbonaceous rocks in this region is evident.
Two agencies were found that brought the consolidation of loose sediments into soft rocks. Firstly due to pressure, may be thousands of centimeters thick layers. The deeper layers get greatly heated, compressed and hardened with internal flows of liquid/viscous fluids. This allowed the clay rocks and the particles to get welded inseparably. Next agency has been identified as the deposition of the cementing material into the existing material by percolation and by growth of new materials that used the decomposed components of the prevalent material.
The place was situated about 40Km from the Mega city of Visakhapatnam, that has been attracting many a foreign tourists. Recently a team of students from US went on an educational trip to the Buddhist site and as well the nearby Lingalgutta. The word gutta in Telugu language stands for a small hillock that is constituted by protruding rock boulders and blackish grey huge stones. The team explored the surroundings. The caretaker informed that many a Buddhists from Japan, Nepal, China and neighboring countries visited the region but it seems the Heritage site of the Globe has only received meager donations to upkeep and develop the region and its scenarist beauty.
OBSERVATIONS:
The study indicated that the molten material flowed from Earth’s core, that dependent on the chemical composition of the then existing soil of this region underwent chemical reactions. This generated the different kinds of minerals. The North-South direction of the flow of these mineral materials led to the present day appearance of the Hillocks. The significant observation is that the different strata of the hillock formations clearly exhibited the clay content. The primary indications for my observations are the Garnets and the Lead content of the different strata of the layered formations.
The presence of pebbles and clay material with embedded Garnets has been a very illuminating aspect of the lava flow cooling that happened millions of years ago. But much more study needs to be made to ascertain the impact of vapors that emanated from cooling of lava flows, on the river bed, to get details of the Geo-Topographical features of the Bojjannakonda and Lingalagutta region.
RESULTS:
The picture depicts the photographs of the five different samples.Please see the post script below.
Five important samples have been selected for the present study and results obtained are detailed below as findings.
Sample 1:
It is formed from Red Soil under pressure as a compact material. The color implied presence of some iron oxide.
Sample 2:
This is white Clay material, formed as a solid state stone like substance. The White Part of it implies change to Calcite Chips due to pressure and chemical changes. Aluminum content as Al 3+ is significant.
Sample 3:
It is Red Soil by pressure and it has been compacted. Due to lava intrusions the color was changed to brownish black and in it some pebbles were changed to Garnets. The garnets are isometric mineral and thus isotropic in thin section. These also were found to exist as neo-silicates based on SiO4 structural unit. Almandine Fe3 Al 2 (Si3 O 12) has been found to be present that has usually deep red to brownish black color and i.e. pink in thin sections. The Fe-rich garnet i.e. the almandine being the most common garnet of this region has been found present in aluminous schists.
Sample 4:
It is a Silicon dioxide bed sample, which has hardened due to pressure and has presence of several pebbles.
Garnets general formula is A3 B 2 (Si3O12) where the A-sites are cubic sites containing large divalent cations such as Ca, Fe, Mg or Mn and B-sites occupied by smaller trivalent ions such as Al3+ and Fe 3+ .
Sample 5:
It is a Silicon dioxide bed sample, which has hardened due to pressure and has presence of several pebbles.
Garnets general formula is A3 B 2 (Si3O12) where the A-sites are cubic sites containing large divalent cations such as Ca, Fe, Mg or Mn and B-sites occupied by smaller trivalent ions such as Al3+ and Fe 3+ .
Sample 5:
It showed the existence of quartzite particulate matter, which formed string layers.
ACKNOWLEDGMENT:
The author is thankful to late Radhakrishna, Asst. Director of Mines and Geology, Visakhaptnam for introducing him to Gemology. He is also thankful to Dr.K.Lakshmi Narayana,(Retd) Professor of Physics, Shivaji University, Kolhapur for guidance on this project.
ACKNOWLEDGMENT:
The author is thankful to late Radhakrishna, Asst. Director of Mines and Geology, Visakhaptnam for introducing him to Gemology. He is also thankful to Dr.K.Lakshmi Narayana,(Retd) Professor of Physics, Shivaji University, Kolhapur for guidance on this project.
Post script
For the details and identification of the five different samples shown here, contact may be made to the author of the article, at his corresponding address in Visakhapatnam.
For the details and identification of the five different samples shown here, contact may be made to the author of the article, at his corresponding address in Visakhapatnam.
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