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{{Use dmy dates|date=September 2019}}
{{Use Indian English|date=September 2019}}
{{Infobox settlement
| name = Angadipuram Laterite
| native_name =
| native_name_lang =
| other_name =
| settlement_type = city
| image_skyline = Laterite formation on gneiss. C 009.jpg
| image_alt =
| image_caption =
| nickname =
| pushpin_map = India Kerala
| pushpin_label_position = right
| pushpin_map_alt =
| pushpin_map_caption = Location in Kerala, India
| coordinates = {{coord|10.9925|N|76.2042|E|display=inline,title}}
| subdivision_type = Country
| subdivision_name = {{flag|India}}
| subdivision_type1 = [[States and territories of India|State]]
| subdivision_name1 = [[Kerala]]
| subdivision_type2 = [[List of districts of India|District]]
| subdivision_name2 = [[Malappuram district|Malappuram]]
| established_title = 
| established_date =
| founder =
| named_for =
| government_type =
| governing_body =
| unit_pref = Metric
| area_footnotes =
| area_total_km2 =
| area_rank =
| elevation_footnotes =
| elevation_m =
| population_footnotes =
| population_total =
| population_as_of =
| population_rank =
| population_density_km2 = auto
| population_demonym =
| demographics_type1 = Languages
| demographics1_title1 = Official
| demographics1_info1 = [[Malayalam language|Malayalam]], [[English language|English]]
| timezone1 = [[Indian Standard Time|IST]]
| utc_offset1 = +5:30
| postal_code_type = 
| postal_code =
| registration_plate =
| website =
| footnotes = National Geological Monument
}}

'''Angadipuram Laterite''' is a notified [[National Geological Monument|National Geo-heritage Monument]]
<ref name=gsi1>{{Cite web |url=http://www.portal.gsi.gov.in/portal/page?_pageid=127,529542&_dad=portal&_schema=PORTAL |title=National Geological Monument, from Geological Survey of India website |access-date=2017-05-23 |archive-url=https://web.archive.org/web/20170712055947/http://www.portal.gsi.gov.in/portal/page?_pageid=127,529542&_dad=portal&_schema=PORTAL |archive-date=2017-07-12 |url-status=dead }}</ref><ref name=gsi2>[http://pib.nic.in/newsite/PrintRelease.aspx?relid=137573 Geo-Heritage Sites, Minister of Mines Press release, 09-March-2016]</ref><ref name=gsi3>[http://naturalheritage.intach.org/wp-content/uploads/2016/09/Geoheritage-Monograph.pdf national geo-heritage of India], [[Indian National Trust for Art and Cultural Heritage|INTACH]]</ref> in [[Angadipuram]] town in [[Malappuram district]] in the [[southern India]]n state of [[Kerala]], [[India]]. The special significance of Angadipuram to [[laterite]]s is that it was here that Dr. [[Francis Buchanan-Hamilton]], a professional surgeon, gave the first account of this rock type, in his report of 1807, as "indurated clay", ideally suited for building construction.<ref name=Buchanan>{{Cite web|url=http://diglit.ub.uni-heidelberg.de/diglit/buchanan1807bd2 |author=Buchanan, F.|year=1807|title= ''A Journey from Madras through the Countries of Mysore, Canara and Malabar'', Volume II|accessdate=2009-10-17|publisher=}}</ref><ref name=Schellman/> This formation falls outside the general classification of rocks namely, the igneous, metamorphic, or sedimentary rocks but is an exclusively "sedimentary residual product". It has a generally pitted and porous appearance. The name laterite was first coined in India, by Buchanan and its etymology is traced to the [[Latin]] word "letritis" that means bricks.<ref name=Buchanan/><ref name=Schellman/> This exceptional formation is found above parent rock types of various composition namely, [[charnockite]], [[leptynite]], [[anorthosite]] and [[gabbro]] in Kerala. It is found over [[basalt]] in the states of [[Goa]], [[Maharashtra]] and in some regions of [[Karnataka]]. In [[Gujarat]] in [[western India]], impressive formations of laterite are found over [[granite]], [[shale]] and [[sandstone]]..<ref name=Schellman>{{Cite web|url=http://www.laterite.de/|title= An Introduction in Laterite|author= W. Schellmann|accessdate=2009-09-20}}</ref><ref name=Monument>{{Cite web|url=http://www.portal.gsi.gov.in/portal/page?_pageid=127,529429&_dad=portal&_schema=PORTAL&linkId=1080|title=Monuments of economic significance|work=Laterite in Angadipuram, Malappuram district, Kerala|accessdate=2009-09-20|publisher=Geological Survey of India|archive-url=https://web.archive.org/web/20110721161732/http://www.portal.gsi.gov.in/portal/page?_pageid=127,529429&_dad=portal&_schema=PORTAL&linkId=1080|archive-date=21 July 2011|url-status=dead}}</ref><ref name="GSI">{{cite book|title= Geological Monuments of India |work= Laterite in Angadipuram, Malappuram district, Kerala |pages=46–48|publisher=Geological Survey of India|year=2001}}</ref><ref name=Balasubramanyam>{{Cite book|last= Balasubramanyam|first= K. C.|author2= Shah, S. D.|title= Mineralogy and utilization technology of laterites from W. India|accessdate= 2009-09-20|url= http://www.library.iitb.ac.in/~mnj/gsdl/cgi-bin/library?e=d-00000-00---0PHD--00-1--0-10-0---0---0prompt-10---8-------0-1l--11-zh-50---20-help---10-3-1-00-0011-1-0gbk-10&cl=CL2&d=HASH01bad3547a5160c2053d4843&x=1|publisher= Indian Institute of Technology, Bombay|year= 1983}}{{Dead link|date=May 2019 |bot=InternetArchiveBot |fix-attempted=yes }}</ref>

Apart from its use as bricks in building construction, it has other substantial economic value, since it has been established that laterites are closely juxtaposed with aluminium ore (bauxite), iron ore and nickel ore mineral deposits in many parts of Kerala.<ref name=Monument/>
[[File:Laterite monument. C 002.jpg|thumb|left|A monument giving details of the [[Laterite]]s over a pedestal made of laterite]]
The [[Geological Survey of India|GSI]] has erected a monument at Angadipuram (see picture) where the laterite formations were first identified, as one of the 26 monuments declared as National Geological Monuments, on the occasion of the "International Conference on Laterization" held in 1979.<ref name=Monument/>

Angadipuram is also well known as a pilgrimage centre for its famous temples, the Thirumandhamkunnu temple and the Tali temple.<ref name=mallapuram>{{Cite web|url=http://malappuram.nic.in/tour-attractions.html|title=Tourism Attractions|accessdate=2009-10-03|publisher=National Informatics Centre|archive-url=https://web.archive.org/web/20060906152853/http://malappuram.nic.in/tour-attractions.html|archive-date=2006-09-06|url-status=dead}}</ref>

==Geography==
[[File:Kerala ecozones map labelled3.png|thumb|left|[[Kerala]] [[Agroecology|agro-ecological zones]] map]]
Angadipuram is situated in the [[Malappuram district]], which lies in northern Kerala, and is bounded on the north by Wayanad and Kozhikkode districts, on the northeast by [[Tamil Nadu]], on the southeast and south by [[Palakkad District]], on the southwest by [[Thrissur District]], on the west by the [[Arabian Sea]], and on the northwest by [[Kozhikode District]] (see Kerala eco zones map). The geographical distribution of laterite is not limited to Angadipuram in Malappuram district but it is also found in the midland regions and highlands of Kerala. Its occurrence extends to [[Alappuzha|Aleppey]], [[Quilon]], [[Trivandrum|Thiruvananthapuram]], [[Kottayam]], [[Trichur]] and [[Kannur|Cannanore]] districts. Overall, in the landform of Kerala which has seven landscape ecological zones, laterites account for a major share of 50%. This land form comprises lateritic [[mesa]], mounds, slopes and ridges. This dominant laterite setting is delimited between altitudes {{convert|50|m|ft}} and {{convert|150|m|ft}} (though found up to elevation {{convert|2000|m|ft}} and extends from the northern end to the southern tip of the state. Further, as the topography changes a few kilometers from the sea to the east, there are numerous valleys called ''elas'' where patches of [[paddy field]]s, [[coconut]] and [[arecanut]] groves are seen. Incidence of laterite in other parts of India is reported in the states of [[Karnataka]] [[Maharashtra]] and [[Gujarat]].<ref name=Schellman/><ref>{{Cite web|url=http://www.mapsofindia.com/maps/kerala/geography-and-history/soil-and-vegetation.html|title=Kerala Soil and Vegetation|accessdate=2009-10-03}}</ref><ref name=land>{{Cite web|url=http://144.16.93.203/energy/HC270799/LM/SUSLUP/Thema5/165/165.pdf|title=Sustainable Land Management in Kerala, India: A Biophysical Approach|work=Landscape Ecological Analysis|pages=5–6|accessdate=2009-10-03|archive-url=https://web.archive.org/web/20041126102639/http://144.16.93.203/energy/HC270799/LM/SUSLUP/Thema5/165/165.pdf|archive-date=2004-11-26|url-status=dead}}</ref><ref name=keren>{{Cite web|url=http://www.kerenvis.nic.in/files/pubs/SOE_05/chapter1_p1-12.pdf|title=Introduction Chapter 1|work=Geology of Kerala|pages=4–5|accessdate=2009-10-03|archive-url=https://web.archive.org/web/20090410043800/http://www.kerenvis.nic.in/files/pubs/SOE_05/chapter1_p1-12.pdf|archive-date=2009-04-10|url-status=dead}}</ref><ref name=gov>{{cite book|title= GSI Miscellaneous Publication No. 30 (reference=PGSI-101(2000)|work=Laterite|page=5|publisher=Geological Survey of India|year=1970}}</ref>

Apart from India, its global occurrence in the form of vast deposits of lateritic bauxites with rich production is reported in [[Australia]], [[Brazil]], [[Guinea]], [[Guyana]], [[Suriname]] and [[Venezuela]].<ref name=Schellman/>

;Climate

The intense southwest [[Monsoon]] rainfall in [[Kerala]] (average annual rainfall is 3,107 mm) coupled with high temperatures (mean annual temperatures range from 25 to 27.5 °C in the coastal lowlands to 20 to 22.5 °C in the eastern highlands) and lush vegetation (belongs to the [[Malabar Coast moist forests]] of a [[tropical and subtropical moist broadleaf forests|tropical moist broadleaf forest]] [[ecoregion]] of southwestern India) has accentuated the chemical processes over the base rocks, which has resulted in the formation of laterites. In view of these conditions, the laterization process, which results in formation of laterites, is called the "Tropical disease of rocks".<ref>"GSI" p. 46</ref>

==Structure==
[[File:Laterite quarry, Angadipuram, India. C 004.jpg|thumb|right|[[Laterite]] formation cut into blocks for building construction]]

Laterite is a residual product created by the natural process of rocks [[weathering]] in the hot humid climatic conditions and interaction with water, oxygen and carbon dioxide. In simple terms, it is a soil formation linked to the parent rock material that has evolved because of various powers of nature in the same manner as other types of soils such as [[alluvial soil]], regular soil and [[red soil]]. It is also inferred that paleoclimate dating back several million years has been a causative factor in laterite formation. The residue usually consists of enriched [[iron]], [[aluminum]] and [[titanium]] [[oxides]] in varying proportions. The residue is pitted and porous in appearance. Buchanan, who discovered this formation in Kerala, in his report of 1807 observed: <blockquote>''It is diffused in immense masses, without any appearance of stratification and is placed over the granite that forms the basis of Malayala. It is full of cavities and pores and contains a large quantity of iron in the form of red and yellow ochres. In the mass, while excluded from air, it is so soft, that any iron instrument readily cuts it, and it is dug up in square masses with a pick-axe, and immediately cut into the shape wanted with a trowel or a large knife. It, very soon after, becomes as hard as brick, and resists air and water much better than any bricks that I have seen in India…''</blockquote><ref>"GSI" pp. 46, 47</ref><ref name=indian>{{Cite web|url=http://webcache.googleusercontent.com/search?q=cache:NyDgDaFJqpkJ:www.indianetzone.com/24/indian_soil.htm+History+of+leterite&cd=2&hl=en&ct=clnk&gl=in|title=Indian Soil|accessdate=2009-10-04}}</ref>

In the midland region of Kerala where [[Laterite|lateritic soil]] is predominant, laterites form a residual deposit due to weathering of either crystalline or sedimentary rocks with thickness varying from {{convert|5|-|8|m|ft}}. They also form plateaus. These laterite plateaus are attributed to various phases of uplift of the land in terraced formations in this region. However, in Malappuram, Kozhikode and Kannur districts in the plateau region, laterites are of greater thickness.<ref name=keren/><ref name=portal>{{cite web|url=http://www.portal.gsi.gov.in/gsiImages/information/misc_pub_30_kerala_2005_wm.pdf|title=GSI Miscellaneous Publication No. 30: Geology and Mineral Resources of the States of India, Part IX – Kerala|work=Laterite|pages=21–22|publisher=Geological Survey of India|year=2005|access-date=10 October 2009|archive-url=https://web.archive.org/web/20110721161908/http://www.portal.gsi.gov.in/gsiImages/information/misc_pub_30_kerala_2005_wm.pdf|archive-date=21 July 2011|url-status=dead}}</ref> It is also noted that top layer of laterite, over the crystalline rocks, is very compact. It is also reported by GSI that in Kerala:<ref name=portal/><blockquote>''Quartz veins, joints and fractures can be traced from the top to the bottom of the laterite profile. The laterite profile over pyroxene granulites, metaultramafites and gneisses are characterised by relict foliation that conforms to those of the subjacent rocks which indicate the [[in situ]] nature of the laterite. Porous and spongy texture is discernible in laterites, after meta-ultramafites. Laterite derived from Tertiary sedimentary rocks is well indurated at the top for about {{convert|2|-|5|m|ft}}. Downwards, the profile grades into soft laterite with remnants of gritstone and culminates into a zone of variegated clay.''
</blockquote>

;Chemical composition

It has been inferred from chemical analysis of Angadipuram laterites that they are a derivative of charnockite. The laterite which occurs at an average elevation of about {{convert|60|m|ft}} in the Angadipuram area have an admixture of [[pyroxene]] [[granulite]], [[charnockite]] and [[migmatite]]. The results of the chemical analysis of samples of these laterites indicate the following composition.<ref>"GSI" p. 47</ref>
* SiO2 - 32%, Al2O3 – 29.38%, Fe2O3 –17.38%, TiO2 – 2.05%, Na2O – 0.95%, KO – 0.27%, CaO – 0.3% and MgO – 0.2%

Spatial variations have been recorded in the chemical composition of laterites in Kerala.<ref name=land/>

==Economic uses==

The economic importance of laterites comes from the mining of metals, particularly nickel and aluminium. [[Bauxite]] is an aluminium-rich laterite variety, which is commercially in demand. Bauxite patches are found with laterites overlying for a thickness varying from about {{convert|1|-|50|m|ft}}.<ref name=indian/> Worldwide resources inventory indicates that laterites are a major source of nickel and account for 70% of resources. But nickel production from this source is limited to about 40% of the total world production.<ref>{{Cite web|url=http://www.docstoc.com/docs/2458476/The-Past-and-the-Future-of-Nickel-Laterites|title=The past and furute of nickel laterites|accessdate=2009-10-03| archiveurl= https://web.archive.org/web/20091029171228/http://www.docstoc.com/docs/2458476/The-Past-and-the-Future-of-Nickel-Laterites| archivedate= 29 October 2009 | url-status= live}}</ref> Pepper one of the commercially important spices of Kerala is grown in red laterites as it provides well drained conditions with good water holding capacity. It is also rich in humus and essential plant nutrients.<ref name=portal/><ref name= Sparks>{{Cite book|last=Sparks|first= Donald L. |title= Advances in Agronomy, Volume 82|work=The Pepper Soils|page=289|accessdate=2009-10-03|url=https://books.google.com/books?id=_19ObhE8rRoC&q=Economics+of+laterites+in+Kerala&pg=PA289|publisher= Academic Press|year=2004|isbn= 978-0-12-000780-6}}</ref>

==Access==

Angadipuram has a flourishing tourist industry because of its famous temples and is located about {{convert|16|km|mi}} from [[Malappuram]] on the road to [[Palghat]]. It is an important railway station on the [[Shoranur]] – [[Nilambur]] railway line. The main road from [[Palghat]] (Palakkad) to [[Kozhikode|Calicut]] (Kozhikode) passes through Angadipuram via [[Perinthalmanna]]. Perinthalmanna is the taluk headquarters located {{convert|1.5|km|mi}} from Angadipuram. The nearest airport is [[Calicut International Airport|Calicut]] (Kozikode), {{convert|50|km|mi}} away.<ref name =mallapuram/><ref>"GSI" p. 48</ref>

==Gallery==
<gallery>
File:Abandoned laterite quarry. C 014.jpg|An abandoned [[Laterite]] quarry
File:Sample of laterite brickstone. 012.jpg|Sample of [[Angadipuram]] [[laterite]] brickstone
</gallery>

==References==
{{Commons category|Angadipuram Laterite}}
{{reflist|2}}
{{Kerala}}

[[Category:National Geological Monuments in India]]
[[Category:Geology of India]]

[[Category:Geography of Malappuram district]]
[[Category:Mining in Kerala]]

Angadipuram Laterite - Revision history

>Citation bot at 01:13, 5 November 2020