See also:

• LATERITE (Lat. later, a brick)

LATERITE (See also:

• LAT

Lat. later, a See also:

• BRICK (derived according to some etymologists from the Teutonic bricke, a disk or plate; but more authoritatively, through the French brique, originally a " broken piece," applied especially to bread, and so to clay, from the Teutonic brikan, to break)

brick)  , in See also:

• PETROLOGY

petrology, a red or See also:

• BROWN
• BROWN, CHARLES BROCKDEN (1771-181o)
• BROWN, FORD MADOX (1821-1893)
• BROWN, FRANCIS (1849- )
• BROWN, GEORGE (1818-188o)
• BROWN, HENRY KIRKE (1814-1886)
• BROWN, JACOB (1775–1828)
• BROWN, JOHN (1715–1766)
• BROWN, JOHN (1722-1787)
• BROWN, JOHN (1735–1788)
• BROWN, JOHN (1784–1858)
• BROWN, JOHN (1800-1859)
• BROWN, JOHN (1810—1882)
• BROWN, JOHN GEORGE (1831— )
• BROWN, ROBERT (1773-1858)
• BROWN, SAMUEL MORISON (1817—1856)
• BROWN, SIR GEORGE (1790-1865)
• BROWN, SIR JOHN (1816-1896)
• BROWN, SIR WILLIAM, BART
• BROWN, THOMAS (1663-1704)
• BROWN, THOMAS (1778-1820)
• BROWN, THOMAS EDWARD (1830-1897)
• BROWN, WILLIAM LAURENCE (1755–1830)

brown superficial See also:

• DEPOSIT (Lat. depositurn, from deponere, to lay down, to put in the care of)

deposit of See also:

• CLAY (from O. Eng. claeg, a word common in various forms to Teutonic languages, cf. Ger. Klei)
• CLAY, CASSIUS MARCELLUS (1810-1903)
• CLAY, CHARLES (1801–1893)
• CLAY, FREDERIC (1838–1889)
• CLAY, HENRY (1777–1852)

clay or See also:

• EARTH
• EARTH (a word common to Teutonic languages, cf. Ger. Erde, Dutch aarde, Swed. and Dan. jord; outside Teutonic it appears only in the Gr. 'pq'e, on the ground; it has been connected by some etymologists with the Aryan root ar-, to plough, which is seen in
• EARTH, FIGURE OF
• EARTH, FIGURE OF THE

earth which gathers on the See also:

• SURFACE

surface of rocks and has been produced by their decomposition; it is very See also:

• COMMON

common in tropical regions . In consistency it is generally scft and friable, but hard masses, nodules and bands often occur in it . These are usually See also:

• RICH, BARNABE (c. 1540-1617)
• RICH, CLAUDIUS JAMES (1787-1821)
• RICH, JOHN (1692-1761)
• RICH, PENELOPE, LADY (c. 1562–1607)
• RICH, RICHARD, 1ST BARON RICH (1490?-1567)

rich in See also:

• IRON [symbol Fe, atomic weight 55.85 (0=16)]

iron . The superficial layers of See also:

• LATERITE (Lat. later, a brick)

laterite deposits are often indurated and smooth See also:

• BLACK
• BLACK, ADAM (1784-1874)
• BLACK, JEREMIAH SULLIVAN (1810–1883)
• BLACK, WILLIAM (1841-1898)

black or dark-brown crusts occur where the See also:

• CLAYS, PAUL JEAN (1819-1900)

clays have See also:

• LONG, GEORGE (1800-1879)
• LONG, JOHN DAVIS (1838– )

long been exposed to a dry See also:

• ATMOSPHERE (Gr. fir µ6r, vapour; orkaipa, a sphere)

atmosphere; in other cases the soft clays are full of hard nodules, and in See also:

• GENERAL
• GENERAL (Lat. generalis, of or relating to a genus, kind or class)

general the laterite is perforated by tubules, sometimes with See also:

• VEINS

veins of different See also:

• COMPOSITION
• COMPOSITION (Lat. compositio, from componere, to put together)

composition and See also:

• APPEARANCE (from Lat. apparere, to appear)

appearance from the See also:

• MAIN (from the Aryan root which appears in " may " and " might," and Lat. magnus, great)
• MAIN (Lat. Moenus)

main See also:

• MASS (O.E. maesse; Fr. messe; Ger. Messe; Ital. messa; from eccl. Lat. missa)
• MASS, IN

mass . The See also:

• DEPTH

depth of the laterite beds varies up to 30 or 40 ft., the deeper layers often being soft when the surface is hard or stony; the transition to fresh, See also:

• SOUND
• SOUND, THE (Danish Oresund)

sound See also:

• ROCK
• ROCK (O.Fr. rake, Sp. rota, Ital. rocca; possibly from a Lat. form rupica, from rupes, rock)
• ROCK, DANIEL (1799–187t)

rock below may be very sudden . That laterite is merely rotted crystalline rock is proved by its often preserving the structures, veins and even the outlines of the minerals of the See also:

• PARENT, SIMON NAPOLEON (1855– )

parent mass below; the felspars and other components of See also:

• GRANITE (adapted from the Ital. granite, grained; Lat. granum, grain)

granite See also:

• GNEISS

gneiss having evidently been converted in situ into a soft argillaceous material . Laterite occurs in practically every tropical region of the earth, and is very abundant in See also:

• CEYLON

Ceylon, See also:

• INDIA
• INDIA, FRENCH

India, See also:

• BURMA

Burma, Central and See also:

• WEST
• WEST, BENJAMIN (1738-1820)
• WEST, NICHOLAS (1461-1533)

West See also:

• AFRICA
• AFRICA, ROMAN

Africa, Central See also:

• AMERICA

America, &c . It is especially well See also:

• DEVELOPED

developed where the underlying rock is crystalline and felspathic (as granite gneiss, See also:

• SYENITE

syenite and See also:

• DIORITE (from the Gr. S&oi4eiv to distinguish, from hA through, Epos, a boundary)

diorite), but occurs also on basalts in the See also:

• DECCAN (Sans. Dakshina, " the South ")

Deccan and in other places, and is found even on See also:

• MICA

mica schist, See also:

• SANDSTONE

sandstone and See also:

• QUARTZITE

quartzite, though in such cases it tends to be more sandy than argillaceous . Many varieties have been recognized . In India a calcareous laterite with large concretionary blocks of carbonate of See also:

• LIME
• LIME (O. Eng. lim, Lat. limes, mud, from linere, to smear)

lime is called kankar (kunkar), and has been much used in See also:

• BUILDING

building See also:

• BRIDGES
• BRIDGES, ROBERT (1844– )

bridges, &c., because it serves as a See also:

• HYDRAULIC

hydraulic See also:

• CEMENT (from Lat. caementum, rough pieces of stone, a shortened form of caedimentum, from caedere, to cut)

cement . In some districts (e.g . W .

Indies) similar types of laterite have been called " puzzuolana " and are also used as See also:

• MORTAR

mortar and cement . Kankar is also known and worked in See also:

• BRITISH

British See also:

• EAST
• EAST, ALFRED (1849- )

East Africa . The clay called cabook in Ceylon is essentially a variety of laterite . Common laterite contains very little lime, and it seems that in districts which have an excessive rainfall that component may be dissolved out by percolating See also:

• WATER

water, while kankar, or calcareous laterite, is formed in districts which have a smaller rainfall . In India also a distinction is made between " high-level " and " See also:

• LOW, SETH (1850- )
• LOW, WILL HICOK (1853- )

low-level " laterites . The former are found at all elevations up to 5000 ft. and more, and are the products of the decomposition of rock in situ; they are often See also:

• FINE

fine-grained and sometimes have a very well-marked concretionary structure . These laterites are subject to removal by See also:

• RUNNING

running water, and are thus carried to See also:

• LOWER

lower grounds forming transported or " low-level " laterites . The finer particles tend to be carried away into the See also:

• RIVERS
• RIVERS, ANTHONY WOODVILLE, or WYDEVILLE, 2ND EARL (c. 1442—1483)
• RIVERS, EARL
• RIVERS, RICHARD SAVAGE, 4TH EARL (c. 1660—1712)

rivers, while the See also:

• SAND
• SAND, GEORGE (1804-1876)

sand is See also:

• LEFT

left behind and with it much of the heavy iron oxides . In such situations the laterites are sandy and ferruginous, with a smaller proportion of clay, and are not intimately connected with the rocks on which they See also:

• LIE, JONAS LAURITZ EDEMIL (1833—1908)
• LIE, MARIUS SOPHUS (1842–1899)

lie . On steep slopes laterite also may creep or slip when soaked with See also:

• RAIN (O.E. regn; the word is common to Teutonic languages, cf. Ger. Regen, Swed. and Dan. regn; it has been connected with Lat. rigare, to wet, Gr. 13pixeav)

rain, and if exposed in sections on roadsides or See also:

• RIVER

river See also:

• BANKS, GEORGE LINNAEUS (1821-1881)
• BANKS, NATHANIEL PRENTISS (1816–1894)
• BANKS, SIR JOSEPH
• BANKS, THOMAS (1735-1805)

banks has a bedded appearance, the stratification being parallel to the surface of the ground . Chemical and microscopical investigations show that laterite is not a clay like those which are so See also:

• FAMILIAR (through the Fr. familier, from Lat. familiaris, of or belonging to the familia, family)

familiar in temperate regions; it does not consist of hydrous silicate of alumina, but is a See also:

• MECHANICAL

mechanical mixture of fine grains of See also:

• QUARTZ

quartz with See also:

• MINUTE
• MINUTE (Lat. minutes, small; minuere, to make less)

minute scales of hydrates of alumina . The latter are easily soluble in See also:

• ACID (from the Lat. root ac-, sharp; acere, to be sour)

acid while clay is not, and after treating laterite with acids the alumina and iron leave the See also:

• SILICA

silica as a See also:

• RESIDUE (through the French, from the Lat. residuum, a remainder, from residere, to remain)

residue in the See also:

• FORM (Lat. forma)

form of quartz .

The alumina seems to be combined with variable proportions of water, probably as the minerals hydrargillite, See also:

• DIASPORE

diaspore and gibbsite, while the iron occurs as goethite, turgite, See also:

• LIMONITE, or BROWN IRON ORE

limonite, See also:

• HAEMATITE, or HEMATITE

haematite . As already remarked, there is a tendency for the superficial layers to become hard, probably by a loss of the water contained in these aluminous minerals . These chemical changes may be the cause of the frequent concretionary structure and veining in the laterite . The See also:

• GREAT

great abundance of alumina in some varieties of laterite is a consequence of the removal of the fine particles of gibbsite, &c., from the quartz by the See also:

• ACTION

action of See also:

• GENTLE (through the Fr. gentil, from Lat. gentilis, belonging to the same gens, or family)

gentle currents of water . We may also point out the essential chemical similarity between laterite and the seams of See also:

• BAUXITE

bauxite which occur, for example, in the See also:

• NORTH
• NORTH, BARONS
• NORTH, MARIANNE (1830—1890)
• NORTH, ROGER (1653-1734)
• NORTH, SIR THOMAS (1535?-16o1?)

north of See also:

• IRELAND
• IRELAND, CHURCH
• IRELAND, CHURCH OF
• IRELAND, JOHN (1761-1842)
• IRELAND, JOHN (1838- )
• IRELAND, WILLIAM HENRY (1777-1835)

Ireland as reddish clays between flows of See also:

• TERTIARY

Tertiary See also:

• BASALT

basalt . The bauxite is rich in alumina combined with water, and is used as an ore of See also:

• ALUMINIUM (symbol Al; atomic weight 27.0)

aluminium . It is often very ferruginous . Similar deposits occur at Vogelsberg in See also:

• GERMANY
• GERMANY (Ger. Deutschland)

Germany, and we may infer that the bauxite beds are layers of laterite produced by sub-aerial de-composition in the same manner as the thick laterite deposits which are now in course of formation in the See also:

• PLATEAU (a French term, older platel, for a flat piece of wood, metal, &c., from plat, flat)
• PLATEAU, JOSEPH ANTOINE FERDINAND (1801-1883)

plateau basalts of the Deccan in India . The conditions under which laterite are formed include, first, a high seasonal temperature, for it occurs only in tropical districts and in plains or mountains up to about 5000 ft. in height; secondly, a heavy rainfall, with well-marked See also:

• ALTERNATION (from Lat. alternare, to do by turns)

alternation of wet and dry seasons(in arid countries laterite is seldom seen, and where the rainfall is moderate the laterite is often calcareous) ; third, the presence of rocks containing aluminous minerals such as See also:

• FELSPAR, or FELDSPAR

felspar, See also:

• AUGITE

augite, See also:

• HORNBLENDE

hornblende and mica . On pure limestones such as See also:

• CORAL

coral rocks and on quartzites laterite deposits do not originate except where the material has been transported . Many hypotheses have been advanced to See also:

• ACCOUNT
• ACCOUNT (through O. Fr. acont, Late Lat. comptum, cornputare, to calculate)

account for the essential difference between lateritization and the weathering processes exhibited by rocks in temperate and See also:

• ARCTIC (Gr. "ApKroc, the Bear, the northern constellation of Ursa Major)

arctic climates . In the tropics the See also:

• RANK (O.Fr. rant or rent, mod. rang, generally connected with the O.E. and O.H.G. bring, a ring)

rank growth of vegetation produces large amounts of humus and carbonic acid which greatly promote rock decomposition; igneous and crystalline rocks of all kinds are deeply covered under rich dark soils, so that in tropical forests the underlying rocks are rarely to be seen .

In the warm See also:

• SOIL

soil nitrification proceeds rapidly and bacteria of many kinds flourish . It has also been argued that the frequent thunderstorms produce much nitric acid in the atmosphere and that this may be a cause of lateritization, but it is certainly not a necessary See also:

• FACTOR (from Lat. facere, to make or do)

factor, as beds of laterite occur in oceanic islands lying in regions of the ocean where See also:

• LIGHTNING

lightning is rarely seen . See also:

• SIR

Sir See also:

• THOMAS
• THOMAS (c. 1654-1720)
• THOMAS (d. 110o)
• THOMAS, ARTHUR GORING (1850-1892)
• THOMAS, CHARLES LOUIS AMBROISE (1811-1896)
• THOMAS, GEORGE (c. 1756-1802)
• THOMAS, GEORGE HENRY (1816-187o)
• THOMAS, ISAIAH (1749-1831)
• THOMAS, PIERRE (1634-1698)
• THOMAS, SIDNEY GILCHRIST (1850-1885)
• THOMAS, ST
• THOMAS, THEODORE (1835-1905)
• THOMAS, WILLIAM (d. 1554)

Thomas See also:

• HOLLAND
• HOLLAND, CHARLES (1733–1769)
• HOLLAND, COUNTY AND PROVINCE OF
• HOLLAND, HENRY FOX, 1ST BARON (1705–1774)
• HOLLAND, HENRY RICH, 1ST EARL OF (1S9o-,649)
• HOLLAND, HENRY RICHARD VASSALL FOX, 3RD
• HOLLAND, JOSIAH GILBERT (1819-1881)
• HOLLAND, PHILEMON (1552-1637)
• HOLLAND, RICHARD, or RICHARD DE HOLANDE (fl. 1450)
• HOLLAND, SIR HENRY, BART

Holland has brought forward the See also:

• SUGGESTION

suggestion that the development of laterite may depend on the presence in the soil of bacteria which are able to decompose silicate of alumina into quartz and hydrates of alumina . The restricted See also:

• DISTRIBUTION (Lat. distribuere, to deal out)

distribution of laterite deposits might then be due to the inhibiting effect of low temperatures on the See also:

• REPRODUCTION

reproduction of these organisms . This very ingenious See also:

• HYPOTHESIS (from Gr. inrorcOivat, to put under; cf. Lat. suppositio, from sub-ponere)

hypothesis has not yet received the experimental See also:

• CONFIRMATION (Lat. confirmatio, from confirmare, to establish, make firm)

confirmation which seems necessary before it can be regarded as established . See also:

• MALCOLM
• MALCOLM, SIR JOHN (1769-1833)

Malcolm See also:

• MACLAREN, CHARLES (1782-1866)
• MACLAREN, IAN

Maclaren, rejecting the bacterial theory, directs See also:

• SPECIAL

special See also:

• ATTENTION (from Lat. ad-tendo, await, expect; the condition of being " stretched " or " tense ")

attention to the alternate saturation of the soil with rain water in the wet See also:

• SEASON (0. Fr. seson, seison, mod. saison, Lat. satio, sowing time, the spring, from serere, to sow; in Late Lat. the word is found with its present meaning, the spring being considered as particularly the season of the year)

season and See also:

• DESICCATION (from the Lat. desiccare, to dry up)

desiccation in the subsequent drought . The laterite beds are porous, in fact they are traversed by innumerable tubules which are often lined with deposits of iron See also:

• OXIDE

oxide and aluminous minerals . We may be certain that, as in all soils during dry See also:

• WEATHER (O. Eng. weder; the word is common to Teutonic languages; cf. Du. weder, Dan. veir, Icel. ve8r, and Ger. Wetter and Gewitter, storm; the root is wa- to blow, from which is derived " wind ")

weather, there is an ascent of water by capillary action towards the surface, where it is gradually dissipated by evaporation . The soil water brings with it See also:

• MINERAL

mineral See also:

• MATTER

matter in See also:

• SOLUTION (from Lat. solvere, to loosen, dissolve)

solution, which is deposited in the upper See also:

• PART

part of the beds . If the alumina be at one See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time in a soluble See also:

• CONDITION (Lat. condicio, from condicere, to agree upon, arrange; not connected with conditio, from condere, conditum, to put together)

condition it will be See also:

• DRAWN

drawn upwards and concentrated near the surface . This See also:

• PROCESS

process explains many peculiarities of laterites, such as their porous and slaggy structure, which is often so marked that they have been mistaken for slaggy volcanic rocks . The concretionary structure is undoubtedly due to chemical re-arrangements, among which the See also:

• ESCAPE (in mid. Eng. eschape or escape, from the O. Fr. eschapper, modern echapper, and escaper, low Lat. escapium, from ex, out of, and cappa, cape, cloak; cf. for the sense development the Gr. iichueoOat, literally to put off one's clothes, hence to sli

escape of water is probably one of the most important; and many writers have recognized that the hard ferruginous crust, like the induration which many soft laterites undergo when dug up and exposed to the See also:

• AIR (from an Indo-European root meaning " breathe," " blow ")
• AIR, or ASBEN

air, is the result of desiccation and exposure to the hot See also:

• SUN
• SUN (0. Eng. sonne, Ger. sonne. Fr. soleil, Lat. sol, Gr. ijXior, from which comes helio- in various English compounds)

sun of tropical countries .

The,brecciated structure which many laterites show may be produced by great expansion of the mass consequent on absorption of water after heavy rains, followed by contraction during the subsequent dry season . Laterites are not of much economic use . They usually form a poor soil, full of hard concretionary lumps and very unfertile because the potash and See also:

• PHOSPHATES

phosphates have been removed in solution, while only alumina, iron and silica are left behind . They are used as clays for puddling, for making tiles, and as a mortar in rough See also:

• WORK

work . Kankar has filled an important part as a cement in many large See also:

• ENGINEERING

engineering See also:

• WORKS

works in India . Where the iron concretions have been washed out by rains or by artificial treatment (often in the form of small shot-like pellets) they serve as an iron ore in parts of India and Africa . Attempts are being made to utilize laterite as an ore of aluminium, a purpose for which some varieties seem well adapted . There are also deposits of See also:

• MANGANESE (symbol Mn; atomic weight, 54.93 (0=16)], a metallic chemical element. Its dioxide (pyrolusite)

manganese associated with some laterites in India which may ultimately be valuable as mineral ores . (J . S .