Angadipuram laterite
The Angadipuram laterite is an important laterite deposit in the urban area of Angadipuram in the southern Indian state of Kerala . It has been one of the national geological monuments of India since 1979 .
Location and access
Angadipuram is located in the Malappuram district in the north of the Indian state of Kerala. The district is bordered by the Arabian Sea to the west, the Kozhikode district to the north-west, the Wayanad district to the north, the state of Tamil Nadu to the north-east, the Palakkad district to the south-east and south, and the Thrissur District to the south-west. District .
Angadipuram is only 16 kilometers from Malappuram and can be reached via the road to Palghat . The main road from Palghat (Palakkad) to Calicut (Kozhikode) leads via Perintalmanna and also through Angadipuram. The Taluk headquarters Perintalmanna is only 1.5 kilometers from Angadipuram. Angadipuram also has an important train station on the Shoranur - Nilambur railway line . The nearest airport is in Calicut, 50 kilometers away.
Angadipuram is known as a place of pilgrimage because of its temple complexes - the Thirumandhamkunnu Temple and the Tali Temple .
Climatic conditions
The intense southwest monsoon in Kerala with an average annual rainfall of 3107 millimeters, high temperatures - with annual average temperatures of 25 to 27.5 ° C in the coastal lowlands and 20 to 22.5 ° C in the eastern highlands - and lush vegetation - the Malabar coast with their wet forests belong to the ecoregion of tropical humid deciduous forest in southwest India - they have contributed to accelerating the chemical weathering processes required for the formation of laterites. In view of these conditions, the lateritization process is often referred to as the tropical disease of the rock .
Occurrence
Laterite deposits are not only limited to Angadipuram and the Malappuram district, but can also be found in the low mountain range and in the highlands of Kerala. They also extend to the districts of Aleppey , Quilon , Thiruvananthapuram , Kottayam , Trichur and Cannanore . In Kerala, which has seven eco-zones, laterites make up 50% of the total surface of the state. The laterites usually occur at altitudes between 50 and 150 meters, but can even be found up to 2000 meters. They are found throughout the state of Kerala, mostly as panels, hills, slopes, and topographical ridges. Laterites are also known in other Indian states, for example in Karnataka , Maharashtra and Gujarat . Outside of India, there are huge lateritic bauxite deposits in Australia , Guinea , Guyana , Suriname and Venezuela .
geology
Laterite was found in Angadipuram by the surgeon Dr. Francis Buchanan-Hamilton first described in 1807 as
"Hardened clay stone, as if made for building purposes."
Laterite is difficult to classify because it is a residual weathering sediment that is holey and porous. The name laterite is etymologically derived from the Latin letritis for brick. This extraordinary formation arises as a weathering product in situ over very different parent rocks. In Kerala these are charnockite , leptynite , anorthosite and gabbro . In Goa , Maharashtra and in some parts of Karnataka, laterite is even formed on basalt . In the west Indian city of Gujarat, impressive laterite deposits can be found on granite , slate clay and sandstone .
structure
Laterite is a natural residual weathering product that is created under hot and humid climatic conditions through the action of water , oxygen and carbon dioxide . Put simply, laterite can also be referred to as soil formation , roughly comparable with alluvial soils , regolith and tropical red earth. In addition, tropical paleoclimatic conditions are believed to be a major cause of its formation over the past millions of years. The residue is usually composed of an enrichment of iron , aluminum and titanium oxides in different proportions. Buchanan, who first described this porous and holey residue in 1807, made the following observations:
“It is scattered in immense masses over the granite that forms the Malayala, without any sign of stratification. It has cavities and pores and is very rich in iron, recognizable by its red and yellow ocher color. It occurs in large quantities in the absence of air, but can still be cut through by iron tools due to its softness. Rectangular pieces can be knocked out with iron picks, which are then shaped into the desired shape with a trowel or giant knives. A short time later, a hardening process sets in, which makes the cut pieces hard as a brick. These laterite tiles withstand air and water much better than any other tile I have seen in India. "
At medium altitudes in Kerala with predominant lateritic soils, 5 to 8 meters thick residual laterites formed from crystalline or sedimentary parent rocks. These can also appear as laterite plateaus, which are assigned to different uplift phases here. In the districts of Malappuram, Kozhikode and Kannur, the laterites are much more thick than on the plateaus. Its uppermost layer is very compact above crystalline parent rocks. The Geological Survey of India also lists the following observations for Kerala:
“Quartz veins, fissures and fractures can be traced from the parent rock across the laterite profile. Laterite profiles over pyroxe granulites , metamorphized ultramafitites and also gneisses have a characteristic relictual foliation , which is identical to the foliation in the parent rock and thus clearly confirms the in-situ character of the laterites. On metamorphosed ultramafites, a porous, spongy texture often forms in the laterites. Laterites on Tertiary sediments are compact and solidified in the top 2 to 5 meters, but in the deeper area they become increasingly soft and unconsolidated with sandy inclusions and a culminating colorful layer of clay. "
composition
Chemical analyzes show that the Angadipuram laterite, which is located at an average height of 60 meters, is derived from Charnockites. However, pyroxene granulite and migmatite can also be added. The laterite analyzes gave the following result:
SiO 2 - 32%, Al 2 O 3 - 29.38%, Fe 2 O 3 - 17.38%, TiO 2 - 2.05%, Na 2 O - 0.95%, K 2 O - 0.27 %, CaO - 0.3% and MgO - 0.2%.
The loss of silicon and the strong accumulation of aluminum, iron and titanium are striking . Alkalis and alkaline earths are quite low. The laterites in the state of Kerala, however, show spatial variations in their chemical composition.
Economical meaning
The economic importance of laterites is based on their enrichment in metals, especially nickel and aluminum. Bauxite is an aluminum-rich variety of laterite that is in great demand on the world market. As a major nickel supplier, laterites account for up to 40% of world nickel production. Bauxites are associated with laterites and can occur in accumulations up to 50 meters thick above the laterites.
The Angadipuram laterite is of great importance for the local pepper production in Kerala. Pepper is grown on the red laterites as they provide well-drained soils with high water capacity. They are also rich in humus and essential plant nutrients.
Web links
Individual evidence
- ↑ Geo-Heritage Sites, Minister oif Mines Press release, 09-March-2016
- ^ Geological Survey of India: Geological Monuments of India. Laterites in Angadipuram, Malappuram district, Kerala. 2001, p. 46-48 .
- ↑ Balasubramanyam, KC and Shah, SD: Mineralogy and utilization technology of laterites from W. India . Indian Institute of Technology, Bombay 1983.
- ^ A b Geological Survey of India: Laterite . In: GSI Miscellaneous Publication No. 30: Geology and Mineral Resources of the States of India, Part IX - Kerala . 2005, p. 21-22 .
- ^ Sparks, Donald L .: The Pepper Soils . In: Advances in Agronomy . Volume 82. Academic Press, 2004, ISBN 978-0-12-000780-6 , pp. 289 .