Chapter VI CLAY MINERALOGY Chapter VI

CLAY MINERALOGY

Introduction

Because of the importance of clay materials in ceramics and other industries, in agriculture, in geology, and elsewhere, their investigation goes back far into antiquity.

From the very beginning, it has been observed by the various investigators, that clays and soils very widely differ in their physical and chemical properties. These variations are not in the amounts of the ultimate chemical constituents, but also in the way in which they are combined, or in the manner in which they are present in various clay materials.

In the older literature, a considerable number of concepts were suggested to protray the fundamental and essential components of all clay materials and to explain their variations in properties.

Until very recent years, there has been no adequate analytical tools to determine with any degree of certainity the exact nature of the fundamental building blocks of most clay materials. But during past few decades, considerable investigation of clay materials has been made by using the modern techniques such as spectrophotometric analysis, X-ray 104

diffraction, Infrared, Differential thermal analysis,

Scanning electron microscopy etc. These investigations have thrown more light on the presence of clay minerals, their crystal structures, chemical characters, water content, impurities present etc. which are responsible for physical properties, of clay materials which are mainly considered for their suitability in various industries.

In the present Chapter, the mineralogy of the clay samples from is presented. The results have been obtained by using X-ray diffraction, Infrared,

DTA, TG, and Scanning electron microscopy.

Definition of Clay :

The term 'clay' is being used as a rock term and also as a particle size term in mechanical analysis of sedimentary rocks, soils etc. for years together. In general the term clay implies a natural, earthy fine grain material which develops plasticity when mixed with water. The essential chemical components of clay are silica, alumina and water.

Iron, alkalis, and alkaline earths are nearly always present.

The term clay is used for material that has a variety of origin, such as i) product of weathering, ii) formed by hydrothermal action on pre-existing rocks or iii) sedime­ tary deposition in river or lake or sea. Wentworth (1922) asssigned clay grade to material less than 4 microns in lOS

size, whereas soil scientists have placed clay grade at

2 microns. But most of the clay fraction occurs with size less than 2 which appears to be a convenient limit.

During the earlier days, Kaolinite was considered as the essential clay mineral and the other material occuring as impurity. Soil scientists held the view that the essen­ tial component of all clay materials was a colloid complex.

Clay Minerals :

Clay minerals are phyllosilicates or layer silicates.

They consist of layers with two types of units involved in each layer, the tetrahedral and the octahedral. During the two decades 1920-1940, there were several contributions made towards the study of clay material on the basis of

X-ray diffraction analyses. Hadding (1923) and Rinne

(1924), regarded the clays as independent materials and not amorphous material or colloids. Microscopic and chemical study of clays by Ross and Shannon (1925, 1926) suggested that the components of clay materials are essentially crystalline which may be called as clay minerals. Ross

(1928) proposed a classification of clay minerals. Ross and Kerr (1931) and Correns (1936) gave widely accepted concept of clay mineral. According to this concept, clays are considered to be composed of extremely fine crystalline 106

particles, w~ich are essentially hydrou:; aluminium silicates.

AJ. kla 1 is and alkaline earths are present in some clay minerals wh ; l.!=: in some others, magnesiun1 or iron partly replace some of the aluminium. In addition to clay minerals, some of the non-clay minerals, organic matter and soluble salts also form important constituents of clays. Ross and Kerr (1931, 1934), Ross and Hendricks (1945) made detail study of kaolinite, halloysite and montmorillonite respecti­ vely. Hedricks and his co-workers (Hedricks 1938, 1941,

1942, 1945, Hendricks ~.al. 1936) made significant contri­ butions by way of giving the physico-chemical properties of different clays. Different aspects of clays have been studied by Grim, Bradley and their co-workers (Grim, 1947, 1948 , 1950, Grim e t. a l. 1935, 1937, Bradley, 1945).

The credit of cre ation of s ynthe tic clay minera ls in the laboratory for the first time, goes to Noll (1935). Orcel (1933) was the first to apply the techique of DTA in the study of cla ys. Brindley and Robinson (1946a, 1946b) studied in g reate r details the properties of kaolin minerals. Glaeser (1948), Mering et.al. (1950) studied ad s orption of various lons on clay mine rals and the ir

textures using electron microscope. Mukherjee et.al. (1946) and Chatte rj e e (1949) have studied the e l ectrochemistry

and chemistry of clays from India. 107

Since 1950, there has been a considerable addition of literature based on the various aspects of clays.

X-ray identification and crystal structure study by Brindley

(1951) and Brown (1961). Carroll (1970) published a guide to clay mineral identification using X-ray techniques.

Grim (1953), (1962, 1968) published books on 'Clay Mineralogy' and 'Applied Clay Mineralogy'. DTA investigations of clay edited by Mackenzie (1957), 'Geology of clays' by

Millet, (1970). 'Atlas of infrared spectroscopy of clays and their admixtures' and 'Atlas of electron microscopy of clays and their admixtures' by Vander Marrel and Beutel­ spacher (1968 and 1976) and 'Clay Minerals' (Nemecz, 1981).

Classification of clay minerals :

Several workers have attempted classification of clay minerals, mainly based on the structural characteristics as there is a wide range of chemical composition not only within a single group, but also within single mineral.

Caillare and Henin (1956) proposed a tabular classifi- cation of sheet silicates. This was later modified by

Caillere in 1960 by Millet (1970). It consists of six tables, one for the general classification of hydrated silicates, and kaolinites and serpentinites with real basal spacing of 7 ~' micas and dioctahedral montmorillonites 108

with basal spacing of 10 ~' micas and trioctahedral montmori­ llonites with basal spacing of 10 ~' chlorites having basal spacing of 14 ~' and for mixed layer complexes having varying basal spacing, are the other five tables classifying major groups of clays.

Deer, Howie and Zussman (1962, 1976) have classified clay minerals into five main groups, again on the basis of characteristic basal spacings.

1. Kandite group (7 ~) - kaolinite, dickite and nacrite, anaunite, halloysite, metahalloysite and allophane.

2. Illite group (10 ~) - illite, hyrdo-micas, phengite, brammallite, glauconite and celadonite.

3 . Smectite group (15 ~) montmorillonite, nontronite, hectorite, saponite and sauconite.

4. Vermiculite (14.5 ~).

5 • Palygorskite group palygorskite, attapulgite and sepiolite.

The clay minerals attapulgite and sepiolite from the palygorskite group have chain like crystal structures and are less common. However, the mixed layered minerals which occur very commonly in nature have no place 1n this 109

classification. Though there are few more classifications available, such as those by Franke-Kamenotskii (1961),

Jasmund (1955), the classification scheme for phyllosilicates proposed by AIPEA etc. The one proposed by Grim (1968) and reproduced below is more useful and takes into account not only structure but shape and also expandibility.

Classification of the Clay Minerals by Grim (1968)

I. Amorphous group

Allophane group II. Crystalline

A. Two layer Type

1. Equidimensional

Kaolinite group - kaolinite, nacrite etc. 2. Elongate

Halloysite group.

B. Three layer types 1. Expanding lattice

a. Equidimensional

Montmorillonite group - montmorillonite, Sauconite etc,. Vermiculite

b. Elongate Montmorillonite group - nontronite, saponite, hectorite 110

2. Non-expanding lattice Illite group c. Regular mixed layer types Chlorite group D. Chain - structure type Attapulgite

Sepiolite

Palygorskite

The important clay mineral groups relevant to the present work are described in brief below

The Kandite ·. gro~p : :

The kandite group include a group of minerals characte- rised by a basal spacing of 7 ~. Compared to the clay minerals from other groups, the kandites have a very restri- cted range of chemical composition. Kaolinite, diokite and nacrite and halloysite are described from this group.

Kaolinite : It is chemically a hydrated Al silicate Silica tetrahedra are linked with the aluminium at their centers by a group forming a single layer. Several such layers are stacked together with a periodic spacing of 7 ~' this is clearly reflected in the X-ray diffractobands. On heating 550°C to 600°C, the structure co 11 a p s e s and the 7 ~ peak is lost in the diffractograms. These two features were also observed in lll

the present study in the clays from Sindhudurg district.

Dickite and Nacrite : These are the minerals usually found in hydrothermal deposits. They show chemical affinity with kaolinite but crystallise in monoclinic system in contrast to kaolinite. There lattice structures are different.

They show an intense pask at 7.1 ~but the structure remains stable after heating to 600°C.

Halloysite : It is known to occur in two forms with basal spacing 10 ~and 7 ~ in two forms, namely elongated tubes and spherical globules. The one with basal spacing

10 A is called halloysite and the one with 7 ~ metahalloysite. Recently, AIPEA (1980) has accepted that instead of calling hydrated and dehydrated or halloysite and endellite they should be termed simply as 'Halloysite 10 ~ and Halloysite

7 ~.

A slight deviation in the structure of halloysite occurs from kaolinite in the fact that a water layer is present separating the kaolinite layers.

Metamorillonite is a high alumina endmember of the montmorillonite group with some slight replacement of Al+J by Mg+3 and without any substantial replacement of

Si+4 by At3 At the beidellite end of the montmorillonite- 112

beidellite dioctahedral sheets. When ferric iron replaces aluminium, the dioctahedral nontronite - beidellite series r esults. Saponite, the octahedral mineral from this group contains Mg and Na occurring as interlayer cation.

montomorillonite - (Al, Mg) (0H) si o beidellite - 2 2 4 10

( Ca 2+ , Mg 2+ , Na + )

Illite Group : Illite is the most common clay mineral group occurring in nature. Minerals from the illite group have structures that are similar to those of micas differing onl y in the content of potassium ion which is less and is r e placed by water. Illites and montmorillonite both have same unit layer configuration, however, some of the si licons in illite are always replaced by aluminium and the resulting excessive negative charge is balanced by potassium in interlayer positions. 113

I n the illites, the characteristic 10 R diffraction l i ne 1n X-ray diffraction is often modified into a band bec a us e of the small particle size, variation in the inter l a ye r c a tion, and interlayer hydration. This band tails of f t ow ards the low ang le region. Polymorphs of illites a re a l so known t o occur. That may be distinguished from each o the r by the manner in which sheets stack together in the ' C' direction. They are indicated by a number and a l e tter. The numbers l, 2, 3, indicate layers in a unit c e ll and letters M or T suggest the crystal s y stem mo noc l i nic or triclinic.

I n ord e r t o have a qualitative and quantitative e s t i ma ti on of the major mineral constituents of the clay

samp l es und e r study, the different techniques such as

SEM -, XRD, IR, DTA and TG have been used. The results

thus ob t a ined a r e pre s e nt ed in the following paragr a phs.

Scanning Electron Microscopy

Th e scanning electron microscopy (SEM) is uniquely suited f or study ing clays because it affords a ma gnified,

three dime nsiona l v i ew of the unmodified (natural) clay s urface with g rea t depth of focus. Th e only sample preparation nece s sar y for clays is a thin meta llic coa ting , applied 114

in a v acuum evaporator, which serves to prevent a build­ up o f e lectrons on the surfaces of conducting away s tatic e l ec tricity.

An e lectron optical column, containing electro -mag n e tic lenses, demagnifies an electron source in order to focus a fine beam of electrons o n the specimen surface . This b eam is scanne d across the specimen surface in a rectang ular raster in synchronism with the spot of a cathode ray tube .

Th e sig n a l r e sulting from interaction of the beam with the specime n is col l ec t ed by a suitable electron detector a nd used to modulate the CRT brightness. In most applications, i t is the low-energy secondary electro ns which are thus us e d t o form a picture of the specimen on the CRT face.

Ma n y papers have been published on the applications o f the SEM, bu t o nly a few are concerned with c lay mi n e rals.

Bo r s t a nd Ke lle r ( 1969) studied 49 r eferen ce c l ays. Gillot

( 196 1 ) , Kel l er (197b, 1978 , 1982) , Bohor and Huges ( 1971) ,

Berner and Holdren Jr. (1977), Zalba (19i9) and many other a uthor s h ave inc luded a few SEM micrograph s of clays, but the ins t r um e nt h as not b een ex t e nsive l y applie d in c l ay mineralogi cal research. Bentelspacher and Van der

Ma r e l ( 1968) pulished an 'Atlas of Electron Microscopy o f Clay Mi n e rals a nd the ir Admixture s '. 115

Analytical Method

Two powdered clay samples from Tak and Januali were scanned using 'Cambridge Stereoscan - 150'. Each sample was scanned at different magnifications and only some areas sh owing t ypical and interesting features were photographed . Th e samples were mounted on stub and sputter coated by gold palladium thin film to a thickness of about 200 ~ under a -5 vacuum l ess than 10 em with 1.4 kv current and using a beam with 20 kv energy, fine stream of Argon is passed and coated for 4 minutes. The work was done a t NCL, Pune.

The general charac t ers of the samples studied are s umma ri zed below.

Th e kaolinisation of feldspar illustrated by scanning e l ec tron micrographs include a diverse group of mineral produc ts a nd processes. More than a single t ype of kaolin mi nera l may be formed from the same parent material. The mo rphologies of the kaolin mine rals produced are likewise d i ve rse.

In the present study, the micrographs 1 and 2 (Plate

14, photo l and 2) show fragments of feldspar with spikes of kaolin mineral ostensibly have ' grown' on a base of e tched a nd shattered micro-fragment of feldspar indicating earl y 116

s tage of chemical weathering. In the background, the e longate kaolin appears in scattered form. The microg raph o f clay sample from Tak show plates of dickite ( Plate 14, pho t o 13 ) and dark cavities with walls showing the spikes of kaolin (Plate 14, photo 4) are observed from clay samples fr om Janua li. Anothe r microg raphs of clay from Tak (Plate

15 , photo l) show honeycomb texture with platelets arrang ed on edge-edge cellular pattern. As Walker, et.al. ( 1978) have sugge sted, the y ma y have formed as a result of r eplacement and dissolution of some or all elements of the s i lic ate minerals. Both clay samples in their microg raphs s h ow sh e ave s of kaolinite plate s and 'flower' patte rn (Plate

15 , photo 2 and 3 ) . The pre sence of e longate kaolin ( Plate

15 , photo 4) may be indicative of alternative conditions including both we athe ring a nd hydro-thermal alte ration. On e a lte rnative during weathering is that almost all feldspar we athe rs, in the first stage, is an elongate kaolin mineral tha t later crystallise s to platy kaolinite, thus r e pre s e nting 'metastable' morpholog y. A second alternative i s tha t the e l ongate morpholog y is formed wh e n wea the ring occ urs i n a near- s urfa c e e nv ironment, or in a highland area unde r go ing surface erosion (K e ller, 19 79) . 117

Transmission Electron Microscopy : Th e transmission electron microscope is quite similar t o a normal optical microscope , except that the use of e l e ctrons instead of light for sample illumination results in much superior resolving power and correspondingly much g r e at e r magnification. IN TEM, r e solving power is usually e xpressed in angstrom (~) units, l x 10-8 ern. The TEM is very useful to understand the structure of the material.

An aly tical Technique : Very fine powdered clay samples from Tak and Harkul f r om and Kankauli talukas r e spective l y we re used for transmission electron microscopy, with the Philips EM

30 1 electron microscope at RSIC, Powai, Bombay. The i n s trume nt ha s a resolving powe r of about 2004 ~' corresponding ly with magnifications as high as about SO O, OOOx .

Observations :

Microphotographs of clay samples from Tak (Plate 16, ph o t o l a nd 2) indicat e s the pres e nce of we ll-crystallised kao linite , while microg raphs of clay from Harkul indicate

the pr e sence of both we ll-c rys t a llised a nd non-crys tallised

(P l ate 16 , ph o to 3 and 4) ka olinite . 118

X-ray diffraction of clays : Clays are the mixtures of very fine particles. Clay mi ne ralogy 1n we athering studies is largely concerned with identification of clays, which forms a difficult task. The commonest techniques used in the study of clay minerals are

X-ray diffraction, SEM, TEM, infra red (IR) and diffe rential the rmal analysis (DTA). Out of these, X-ray diffraction r ema ins the major technique for clay mineral identification.

X-ray diffraction is concerned with determining the spacings between the different planes in the cry stal lattice and certain spacings are characteristic of certain minerals. In practice, a curve is usually obtained showing the s pacing s and intensity of lines. Peaks on the curve, reveal the various minerals present.

Clay minerals are layer silicates in which sheets of a t oms , of the s tacked one above another in various ways with diffe rent kinds of atoms lying b e tween the l ayers a nd holding them toge ther. As they have planar structure, the 'd' spacing s corresponding t o 001 reflections are important 1n the identification. Th e common me thod of sample packing in a window randomises all the r e flec tions. I t is observed tha t 119

i f by ~orne means, the clay particles are allowed t o lie flat on the subtrate, then in the X-ray diffraction only the 001 r e fl e ctions characteristic of the individual mineral would be enhanced. Variations in these 001 reflections also help in the study of interstification, if any.

Analytical method :

The clay samples from various localities have been s ubj e cted t o X-ray diffraction analysis to ide ntify the mine ralogy of the samples. In addition to clay minerals, som e other minerals associated 1n the clays are also ide ntified. The XRD data of various samples is given in Table Nos. 6.1 to 6.22.

Samples were crushed to 250 mesh ASTM sieve. For separation of clay fraction, 25 gm of each sample were soake d in wate r for 24 hours using NH40H as dispersing agent. The mixture was shaken for about l hour on shaking machine for better dispersion. From suspension, the clay frac tion has been collected by pipe tte a na l ysis. Th e s e s ampl e s were allowed to settle on a glass slide at normal

room temperature in order to get the oriented mount. 120

The following treatment was made

a. On air dried sample

b . Gl yco lated sample and c. Sample heated up to 550°C to 600°C for 2 hours

The samples were run at the laboratory of Geological

Survey of Iran (Tehran) on the X-ray diffractometer (Type

Siemens, West Germany) operated at 30 KW and 24 MA (Cu) and

28 MA (Co) using Nickel filter and Cu ~radiations of wave leng th 1.542 ~ and using iron filter Co Ka radiations of wa ve len g th 1. 79 · ~. The scanning speed was maintaine d at

1 ° e m per min linear chart accordingly, s tarting with 28 =

4 ° with both the radiations.

For the identification of different peaks, Hana~olt's met h od h as b een us e d, in which the peaks a r e compared with

ASTM cards.

Distribution of clay minerals :

In the following paragraphs, distribution of clay minerals from clay samples unde rstud y is given.

Kudal Taluka :

Kao linite is the dominating clay mineral seen in the samp l es from Kudal taluka. The most commonly associated 121

mineral with Kaolinite is Quartz. In some localities (Pat), a mixed l ayer of Kaolinite, illite and unaltered Potash feldspars are also seen. A f ew low intensity peaks of illite are a lso identified.

Vengurla Taluka :

In this taluka, almost in all the samples, a mixture of Kaolinite, Quartz and Potash feldspars is identified. However, the Kaolinite is abundantly present.

Kankauli :

In Kanka uli t aluka, kaolinite is dominantly present. In some localities, illite has been noted . Here, in this locality, the unaltered feldspars are very few.

Malvan : The important clay mineral in this locality is again

Kao linite, but in taluka, in addition to kaolinite, o ther minerals like micas (muscovite), a few quartz and illite are present.

Sawa ntwadi : Kaolinite is dominantly occurring clay mineral of sampl e s collected from this taluka. He re, kaolinite is associated with f e ldspars, quartz a nd a few illite . Table ().l 1XRO Data Locality S!I'W&nt.,.adi 11 (Sa... ant..,adi 1!1lu~•)

( 6. 097)

) , e d-spacing Relative Remarks Intensity

5.09 10.08 6.09 Illite 7. 17 7.16 45.11 Kaolinite 7.93 6.48 4.57 Hie roc line 11.59 4.45 3.&5 Kaolinite 11.85 4.35 3.96 Kaolinite 12.14 4.25 43.89 Quartz 12.44 4.15 3.65 Kaolinite 13.05 3.95 6.82 Hicroclina 13.54 3.82 3.29 Kaolinite 14.05 3.68 3.29 Hicrocline, Illite 14. 51 3.57 32.!:)1 Kaolinite, Hie roc line 14.89 3.48 56.70 Hicroc1ine 15.51 3.34 100.00 Kaolinite, Quartz, Hicrocline, Illite 15.77 3.28 12.19 Hie roc line 16.04 3.23 18.65 Hie roc line 17. 19 3.02 6.70 Hie roc line 17.60 2.95 G. 70 , Hicroc1ine 17.95 2.90 4.26 Hicroc 1ine 18. 76 2.78 2. 13 Hicrocline 20.00 2.61 4.14 Hicrocline, Illite 20.20 2.59 2.74 Hie roc line 20 .47 2.55 4 . 26 Kaolinite 20.78 2.52 4.57 Kaolinite, Hie roc line, llli te 21.36 2.45 12.80 Quartz 22. 55 2.33 13.53 Kaolinite, Hie roc line 23.0':) 2.28 18.29 Kaolinite, Quartz Hie roc line, Quartz 23.57 2.23 10.97 Kaolinite, 24.48 2.15 15.24 Hicrocline, Illite Quartz 24. 8& 2. 12 12.80 Kaolinite, Quartz, Illite 1.6.85 l. 98 7. 92 Kaolinite, 27.66 1. 92 4.38 Kaolinite Quartz 29.46 1. 81 69.50 Kaolinite, 30 .36 1. 76 8.53 Kaolinite Quartz 32.35 1. 67 35.45 Kaolinite, Quartz, Illite 35.45 1. 54 20.72 Kaolinite,

Quar tz are Al pha-Qua rtz. Table 6.2 XRD Data Locality Talawade ()

( 5.319)

Sr.No. e d-spacing Relative Remarks Intensity

l. 7. 10 7.19 19.68 Kaolinite 2 . 11.58 4.46 3. 19 Kaolinite 3. 11. 80 4.37 2.65 Kaolinite 4. 12.14 4.26 30.85 Microcline, -Quartz 5 . 13. 00 3.97 3.45 Microcline 6. 13.55 3.84 8.35 Microcline, Kaolinite 7. 13. 90 3. 74 2.65 Microcline, Kaolinite 8. 14.50 3. 57 12.76 Microcline, Kao 1 in it e 9. 14. 92 3.47 6. 11 Microcline

10 . 15 . 51 3.34 100. 00 - Quartz + Kao 1 in it e + Microcl ine 1 l . 15.76 3 . 29 2. 76 Mi l: roc1ine 12. 15. 99 3.24 28 .72 Microcline 13. 17.20 3.02 2.12 Microcline 14. 17.52 2 .95 3.19 Microc 1ine 15. 17. 97 2.89 3.82 ! 6. 18 . 93 2 . 7 5 l. 59 Kaolinite, Mi croc line 17. 19.97 2.62 2.65 Mi croc line 18 . 20.95 2 . 56 2 . 28 Kao linite 19. 20. 13 9 2.50 l. 06 Microcline 20 . 21. 34 2 . 45 9.20 - Quart z 21. 21.60 2 .42 2. 12 Microc line Mi croc line 22 . 22.45 2. 34 4.25 Kaolinite, Kaolinite 23 . 23. 07 2. 28 2. 76 - Quartz, Microcline 24. 23 . 57 2.23 2. 12 - Qua rt z , Microcline 25 . 24 . 47 2. 16 3. 72 Kaolinite 26 . 24 . 9 1 2. 12 2.92 - Qua rt z , - Quartz, Kao linite 27. 26 . 85 1. 98 4. 25 - Ouart z , Kaolinite 23 . 29 . 46 l . 81 20.74 2') . 2 CJ . 77 1. 80 2. 12 - Quart z , Kaolini te 30 . ~l 2 . :; 5 l. 6 7 2 . 92 - Qu;lrtz , Kao linite :J l. J ::, . 4 ~ 1. 54 3 . 29

. ,. l 7. • Table 6.3 XRD DatA Locality Qtavane (Sawnntwndl Talukil )

(5.063)

Sr.No . e d-spacing Relative Remarks Intensity

1. 7. 1 7 7.15 75.94 Kaolinite

2 0 11.50 4.45 4.55 Kaolini te 3 0 11. 86 4.35 2.43 Kaolinite

4 0 ~ 2 0 ll· 4.24 29.87 Qua rtz 5 0 12. 3 7 4 0 16 l. 51 Kaolinite 6 . 13.43 3 . 84 3 . 03 Kaolinite 7 0 14. SQ 3. 57 42.52 Kaolinite

8 0 15 . 5Q 3.34 lOO.QQ Quartz , Ka o linite , ~1 i c r n c l in e 9. 17. 16 3.Q3 2.Q2 Microcl i ne 10. 20.45 2 .55 4.05 Kaolinite

11. 21. Q3 2.49 7.59 Ka o linite 12 0 21.35 2 . 45 10.63 Quartz

J 3 0 22 . Q8 2 . 3 7 3 . 54 Ka o linite

14 0 22.50 2.33 9.87 Kaolinite 15 0 22.98 2 . 29 1. 51 Kaolinite 16 0 23 . 1 Q 2.27 18 .47 Quartz Quartz J 7. 23 . 57 2 .23 14 .68 Ka o linite , Qua r t z 18 . 24 . 86 2 . 12 7.08 Kao lin it ~ , quartz 19 . 26.84 l. 98 6 . Q7 Ka o linitf', f) uart z 20 . 29 . 47 l. 81 11. 13 Ka o lin ite , Quar t z 21. 32. 38 l. 6 7 4. 55 Ka o l ini t e , (Ju a r t z 2 2 0 35.4 5 l. 54 18 . 2 2 4. Q) Ka o lin ite 23 . 37 . QQ 1. 48

All Quart z are Alpha-Qua rt z . Table b.:. : XRD Data Locality Sawantwadi Poo l ( Sawantwadi Taluka)

(8.928)

S r. No. e d-spacing Relative Remarks Intensity

l. 3. 05 14.47 42 .85 Ch l orite

2 . 4 . 3 7 10 . 10 9.37 llli te

J . 6. 13 7. 21 13.39 Kaolin ite

4. 6 . 8 5 6.4 5 8.92 Hie r oc line 5 . 9 . 12 4.85 35.71 Chlori t e

b . 10 . 32 4.29 45.53 Quartz

7 . 10 . 95 4.05 16.07

k . 11. 43 3 . 88 8 . 03 Hie r oc line

g. 11 . 70 3.79 9.82 Chlori te 10 . 12 . 10 3.67 10.44 Illite, Microcline

11. 12. so 3 . 55 11. 16 Kaolinite, Hicrocline

1 2 . 1 3. 2 5 3. 3 5 100.00 Kaolinite, Illite, Microcline Quartz

l 3 . J 3. 7 J 3 . Z~ 94.63 t_licroc line

1 4. 14 . 30 3. 11 8.92 Kaolinite

J 'i. 15.02 2.97 6.69 Microcline

I b. I 5 . I 0 2.95 5.35 ~ hl o rite

I 7 . I 7 . 40 2 . 57 J 0. 71 Kao linite, Microcline

l .~ . 18 .20 2 . 46 29.0 1 Qua rtz

l ':J . 18 . 77 2 .39 7. 14 Kaolinite, Microcline

20. 19.68 2 . 2 8 15. l 7 Kaolinite, Quartz

2 1 . 20 .09 2.24 10 .71 Kaolinite, Quartz

L.'L . 2 1 . 19 2. l3 22 .32 Kaolinite, Quartz

L. 3 . 22 . 82 l. 98 12.49 Kaolinite, Illite, Quartz .C hl orite 24. 23.07 1. 96 6.24 25.00 l. 82 28.56 Kaolinite, Quartz

LL . 1 s. 56 l. 7 8 7. 14 Kaolinite Kaolinite, Illite, Quartz '!.7 . 27 . 46 l. 6 7 10.26 Kaolinite, Quartz 2tl . 2'!.90 l. 54 25.89

:\ 1 1 ({ll :, ,·u. ;,ce A1pha-Quart:t. fable 6.) : XRD Data Locality Mumras (Sawantwadi !eluka)

(&.25)

Sr.No. e d-spacing Relative Remarks Intensity

I. 4.26 12.06 11. 8 7 Sepoli te 2. 5. 10 10.00 10.25 Illite

3. 7.14 7.19 68.75 Kaolinite 4 . 10 . 37. 5.00 3.75 Illite

"J . 11 . 55 4.4& 7.50 Kaolinite, Sapolite, Illite 6. 12. 13 4.25 53.75 Quartz 7. 12 .73 4.06 2.50 Sepolite 8. 12.96 3.98 4.50 Sepolite 9 . 13. 30 3.89 3. 12 Sepolite 10. 14.49 3.57 37.50 l'aolinite, Sepolite

11. 15.47 3.35 100.00 Kaolinite, Quartz, Sepolite, Illite

i 2 . 16 .30 3. 18 3. 7 5 ~!lite 13 . 16 . 94 2.91 3. 75 Sepoli te 14. 19 .47 2.68 5.62 Sepolite

1 5. 20 .05 2.61 1. 87 Illite, Sepolite 16. 20 .48 2. 55 .. 6.25 Kaolinite, Sepolite I 7 . 21. 36 2 .46 17. so Quartz 18 . 22.08 2.38 5.31 Kaolinite 19. 22.46 2.34 5.62 Kaolinite Sepolite 20. 23.10 2. 2 7 9.06 Kaolinite, Quartz, 21. 23.57 2.23 9.06 Sepolite Illite 22 . 24.49 2. 15 4.37 Kaolinite, Quartz, Sepolite 23. 24.35 2.12 14.37 Kaolinite, Illite 24. 26.85 1. 98 6.87 Kaolinite, Sepolite, Quartz 2S. 29.48 1. 81 2 3. 12 Illite 26 . 32 .29 1.67 6.25 Kaolinite 27. 32.65 1. 65 2.50 Kaolinite 28 . 33.52 1. 61 4.68 Kaolinite 29. 35.45 1. 54 20.62 Kaolinite 30 . 36.80 l. 49 5.00

All Quar tz are Alpha-Quartz. Teble 6.(,: XRD Data Locality Nemale (Sawantwadi Tnlukll)

(6.451)

Sr.No. e d ·spacing Relative Remarks Intensity

1. 4.39 10.06 3.22 Illite 2. 6.16 7. 16 11.61 Kaolinite 3. 6. . 82 6.48 4.83 Microcline 4. 10.00 4.43 2.25 Kaolinite 5. 10.44 4.26 56.44 Quartz 6. 11. 17 3.97 12.90 Microcline 7. 11.64 3.82 19.99 Kaolinite 8. 12.03 3.69 10.32 Microcline, .Illite 9. 12.40 3.58 7.09 Kaolinite, Microcline l 0. 12.77 3.48 22.25 Micro<.. line ll. 13.28 3.34 100.00 Kaolinite,_ Microcline, Illite, Quartz 12. 13.73 3.24 63.21 Microcline 13. 14.34 3.10 11.61 Kaolinite

1L. . 14.71 3.02 10.32 l'\ic.roc.line 15. 15.10 2.95 9.67 Microcline 16. 15.38 2.90 9.99 Microcline 17. 16.08 2. 77 6. 77 Microcline, Kaolinite 18. 17. 12 2. 6i" 10.64 Microcline, llli te 19. 17.50 2.56 9.35 Kaolinite, Microcline 20. 17. 77 2.52 9.48 Microcline, Illite 21. 18.28 2.45 16.12 Quartz 22. 18.49 2.43 5.16 Illite 23. 19.27 2.33 5.80 Kaolinite, Microcline 24. 19.72 2.28 18.06 Kaolinite, Quartz 25. 21. 12 2.23 9.67 Microcline 26. 20.87 2.16 14.83 Microcline, Illite 2 7 . 21.21 2. 12 12.90 Kaolinite, Quartz 28 . 21. 7o 2.07 3.87 Kaolinite Kaolinite, Quartz, Illite 29. 22.89 1. 98 13.86 30. 23.55 1.92 4.51 Kaolinite Kaolinite 31. 24.48 l. 86 7.74 Quartz 32. 25.05 1. 81 30.31 Kaolinite, Kaolinite, Quartz 33. 25 .23 l. 80 9.35 Kaolinite, Quartz, Illite 34. 27.43 1. 67 8.38 Kaolinite, Quartz 35 . 27 . 70 l. 65 3.67

;, t l (;11art7 a r e Alph

(8.333)

Sr.No. e d-spacing Relative Rema r ks Intensity

l. 4.35 10. 15 7.91 Illite 2. 6.09 7.26 51.66 Kaolinite 3. 9.95 4.45 6.83 Kaolinite 4. 10.35 4.28 37.49 Quart z 5. 10.59 4.19 5.83 Kaolinite 6 . 12.44 3.57 51.66 Kaolinite, Hicrocline 7. 13.23 3.36 100 . 00 Kaolinite, Quartz, Hicrocline, Illite 8. 13.65 3.26 13.33 Hicrocline 9. 14.29 3.12 22 . 49 Kaolinite 10 . 3.02 3.02 7.49 Hicrocline 11. 17.46 2.56 11.66 Hie roc line 12 . 18 . 18 2.46 15.83 Quartz 14. 18.84 2.43 6.83 Hicroc line, I 11 i te

15. 19.07 2.35 8.33 Kaolinite, ~lie r oc line 15. 19.64 2.29 18.83 Kaolinite, Quartz 16 . 20.05 2.24 11.66 Hicrocline, Quartz 17. 20.65 2. 18 4.99 Kaolinite 18. 21. 15 . 2. 13 10 . 83 Kaolinite, Quartz 19 . 22.84 1. 98 7.49 Kaolinite, Illite, Quartz 20. 24.97 l. 82 28.33 Kaolite, Quar t z 21. 27.38 1.67 29.16 Kao linite, Illite, Quartz 22. 28.90 1. 59 4.99 Kaolinite, Quartz Quartz 23. 29.90 1. 54 17.49 Kaolinite, Illite,

All Qua rtz are Al pha-Quartz . Table 6.8 XRD Data. Locality Kankauli, Taluka Kankau1i.

Sr.No. e d-spacing Relative Remarks Intensity

1. 5.06 10.16 7 . 18 Illite 2. 7. 15 7. 1d 13.07 Kaolin! te 3. 7.92 6.49 9.80 Microcline 4. 12.12 4.26 66.66 Quartz 5. 12 . 96 3.98 11.76 Microcline 6. 13.47 3.83 16.99 Kaolinite 7. 13.96 3.70 13.07 Microcline 8. 14.21 3.65 8.49 Microcline, Illite 9. 14.45 3.58 6.536 Kaolinite 10. 14.86 3.48 23.52 Microcline 11. 15.45 3.34 100.00 Quartz, Kaolinite, Hicrocline, Illite 12 . 15.75 3. 29 12.41 Microcline 13. 15.92 3.24 97.38 Hicrocline 14. 16.15 3. 19 5 . 22 Illite 15. 17. 16 3.02 9.80 Hie roc line 1 G. 17.59 2.96 16.34 Hie roc line 17. 17.94 2.90 16 . 34 Hie roc line 18 . 18 .91 2. 7 5 5.88 Kaolinite, Hicrocline 19. 19.92 2.62 5.22 Hicrocline, Illite 20 . 20.79 2.52 5.22 Kaolinite, Hicrocline, Illite 21. 21.31 2.46 22.87 Quartz 2 2 . 22 . 50 2.33 5.22 Kaolinite, Hicrocline 23. 23.06 2. 28 39.21 Quartz, Kaolinite 24 . 23 . 56 2.23 16.34 Quartz, Kaolinite, Microcline 25. 24 . 44 2.16 18.30 Kaolinite, Hicrocline, Illite 26. 24.85 2.12 14.37 Quartz, Kaolin! te 2 7 . 26.84 l. 98 14.37 Quartz, Kaolinite, Illite 28. 28.76 l. 85 8.49 Kaolinite 29. 29.45 1. 81 39.86 Quartz, Kaolinite 30 . 32.33 l. 67 13 . 07 Quartz, Kaolinite 31. 35.45 :.54 43.79 Quartz, Kaolinite, I 11 ite

All Quartz are Alpha-Quartz. Table 6.9 XRD Data. Locality Janauli II, Kankauli Taluka.

(7.812) Sr.No. 0 d-spacing Relative Remarks Intensity

1. 3 .09 14 .28 19. 53 Chlorite 2. 6. 18 7. 15 47.65 Kaolinite 3. 6.8S 6.45 7. 81 Microcline 4. 9 .35 4.74 15.62 Chlorite 5 . 10.40 4.26 63.66 Quartz 6. 11.00 4.03 14.06 Chlorite 7. 11.55 3.84 13.67 Kaolinite 8. 11. 96 3.71 6.24 Microcline 9 . 12. 50 3. 55 22.65 Kaolinite 10. 12.7 5 3.49 11.71 Microcline I I . 13.27 3.35 100 . 00 Quartz, Kaolinite, Hicrocline 1 2 . 13.70 3. 2 5 60.93 Hie roc line 13. 14.73 3.02 8.59 Hicrocline 14. 15. 08 2.95 13.67 Hicrocline 15. 16.20 2. 76 3.12 Kaolinite, Microcline 16. 17.26 2.59 5.07 Hicrocline 1 7 . 17.45 2.56 8.59 Kaolinite 18 . 17.70 2.53 5.46 Kaolinite 19. 18 .23 2.46 35.93 Quartz 20 . 18.75 2.39 6.01 Kaolinite, Microcline, Chlorite 21. 19. 24 2.33 3.90 Hicrocline, Kaolinite, Chlorite 22. 19.70 2.28 22.26 Quartz, Kaolinite 23. 20. 12 2.23 7.03 Quartz, Kaolinite, Hicrocline, Chlorite 24. 20.87 2.16 14.68 Kaolinite, Hicrocline 25. 21.20 2. 12 21.48 Quartz, Kaolinite 26. 21. 79 2. 07 4.68 Kaolinite 27. 22.36 1. 98 12 .10 Quartz, Kaolinite 28. 23.54 1. 92 3. 12 Kaolinite 29. 24.04 1. 89 9. 37 Kaolinite 30. 24.55 1. 85 3.51 Kaolinite 31. 25.02 1. 81 35.93 Quartz, Kaolinite, Chlorite 32. 25.25 1. 80 7. 81 Kaolinite 33. 25.53 l. 78 7.42 Kao 1 in i te 34. 26.62 1. 72 6.09 Kaolinite 35. 2 7. 4 2 1. 6 7 5.85 Quartz, Kaolinite 36. 29.30 1. 57 7.42 Kaolinite 37. 29.94 1. 54 32.02 Quartz, Kaolinite

All Quartz are Alpha-Quartz. I 'I I • \ r I ,, \" ' \Rr f ':1 1_tl I .• r 'I} it y K11 mhh"r'" ''t t 7 (~In I , ..111 I .1 ! 11L1)

(5.263)

S r. No. d-spacin~ Relative Remarks Intensity

I. :, . 13 9.98 t14. 7 3 ~1uscov i le

7. . 7. I 'j 7. 18 I 2. 4 7 Kaolinite 3. 10 .34 4.98 20.52 Muscovite 4. II. 54 4 . 47 7.36 Muscovite

'!. I 2. 12 4.26 59.99 -Quartz

b . I .1 . .1 4 3.87 5.26 Muscovite 7 . 13. 87 3 . 73 3. 15 Muscovite, Kaolinite 8 . 14. 46 3.58 5 . .52 Kaolinite 9 . 14 . 8 5 3.49 7.10 Muscovite 10 . 15 . 49 3.34 100.00 -Quartz, Muscovi le, Kaolinite 11. 16.23 3.20 7.89 Muscovite 12. I 7. 39 2.99 ll. 97 Muscovite

13. 18. 24 2.85 7.36 ~1uscovi te 14. 18.69 2. 79 5. 70 Muscovite

l ~~ . 20 . 19 2. 59 l. 57 Muscovite

16 . 20 .40 2. 56 7.36 Muscovite, Kaolinite l 7. 21. 03 2 . 49 2. 10 Muscovite, Kaolinite

18 . 21 .34 2.45 19.47 Muscovite, - Quartz 19. 22.07 2. 37 2.63 Muscovite, Kaolinite 20 . 23 . 06 2. 2 8 13. 15 - Quartz, Kaolinite 21. 23.56 2.23 13.05 Muscovite, - Quartz 22. 24 . 26 2. 12 l 0. 52 - Quartz, Kaolinite 23 . 26 . 65 1. 99 13. 15 Muscovite, Kaolinite 24 . 26.84 1. 98 3.68 Muscovite, - Quartz 25 . 29.46 l. 81 15.26 - Quartz, Ki!olinite 26 . 32.32 1. 6 7 3. 15 -Quartz, Kaolinite 2 7. 32.60 1. 66 2. 10 Muscovite, Kaolinite 28. 32.93 1. 64 2. 10 ~1uscovi te Kaol i nite 29 . 35 .44 l. 54 13 . 15 Muscovite, -Quartz,

All Quartz are AI plw-Quar tz . Table b.!!: XRD Data Locality Kumbharmatt 3 (Mal van Taluka )

(5.208)

Sr. No . e d-spacing Relative Remarks Intensity

1. 5.16 9.96 16.14 Muscovite/Illite 2. 7. 19 7. 15 44.78 Kaolinite 3. 10 . 35 4.97 6.24 Illite/Muscovite 4. 11.60 4 . 44 3.64 Kaolinite

5 . 12. l 3 4.26 54. 16 -Quartz 6 . 12.36 4.16 1. 56 Kaolinite 7. 14.50 3.57 27 . 08 Kaolinite

8. 15 . 50 3.34 100.00 -Quartz, Kaolinite, Illite/~~s ccv ite 9. 16.25 3. 19 2.08 Muscovite/ Illite l 0 . 17.4 2.98 3 . 12 Muscovite/Illite 11. 18 . 2 5 2.85 2.08 Muscovite/Illite

12. 18 .7 3 2. 77 l. 82 Muscovite/Illite 1 3 . 20 . 4 1 2.56 5.20 Kaolinite / ~scoyj_te 14. 20 . 70 2. 52 1. 56 Kaolinite- Illite

I S . 21. 02 2.49 4.68 Kaolinite 16 . 2 1. 34 2.45 20.83 -Quartz 1 7. 22.011 2. 38 2 . 2 3 Kaolinite 18 . 22 . 50 2.33 4.24 Kaolinite 19 . 23 . 08 2. 28 20. 31 Kaolinite, -Quartz 20 . 23 .5 7 2.23 5. 72 Quartz, Muscovi te 21 . 24.85 2. 21 14.32 Kaolinite, -Quartz Illite 22. 26.6fl 1. 99 6.24 Kaolinite-

2 J . 26 . &4 1. 98 3. 12 - Quartz 24 . 29 .4 5 1. 82 21.87 Kaolinite, -Quartz 25 . 32.34 1. 6 7 7.20 -Quartz, Illite/Muscovite Muscovite 26 . 32.62 1. 65 l. 56 Kaolinite, -Quartz, Muscovi te/llli 27 . 3 5 . 1,4 l. 54 12 .49 Kaolinite, -Quartz,

All f Jtld r t z '' r e Alpha - Quortz. TA b lef-.12: XR!l [)at a Locality Kumbharmatti 4 (M a l vAn Tnluka)

( 5. 319)

Sr.~ o . e d-spacing Relative Remarks Intensity

l. 5. 16 9.94 57.9 7 Muscovite 2 . 7. 21 7. 12 18.61 Kaolinit e 3 . 10. 36 4.97 17.02 Muscovite

4. 11. 57 4.46 6.38 Kaolinite + ~1uscov it e 5. 12. 13 4. 26 63.56 -Quart z 6 . 13. 34 3.87 4. 78 Muscovite 7. 13.88 3. 72 5.31 Kaolinite

8 . l ~. 4 7 3.58 9.57 Ka olinite

9 . 14.85 3.49 5.85 Muscov ite

10 . 15. 50 3. 34 100.00 - Quartz, Kaolinite, Musco v ite l I . 16.26 3. 19 7.44 Mus covite 12 . 1 7. 4 5 2 . 98 9. 57 Mus covi t e 13 . 18. 26 2.85 7.97 Mu scovit e jt,. 18 . 7 2 2. 78 5.31 Musc ovite

15 . 20. 18 2.59 1. 59 Mus cov ite 16 . 20 . 44 2.56 6.91 Ka o linite + Muscovite l 7 . 21.04 2.49 3. 72 Kaolinite + Muscovite 13 . 21 . 36 2.45 13.56 - Qua rtz, ~1uscovi te 19 . 22. 10 2.37 2. 12 Muscovite, Kaolinite 20 . 23. 08 2. 28 14. 62 Kaolinite, - Qua rtz 21. 23.59 2 .23 6.91 Mu scovite , - Quartz 22 . 24 . 86 2.1 2 20. 21 Kao linite , - Quartz 2 3 . 26.67 l. 99 12. £3 Muscovite 2,, . 26.90 l. 98 6.38 - Qua rt z , Ka o linite - Quartz, Muscovite 2j , 29 . 47 I. 81 20.90 Ka o linite, - Quartz, Mus covi t e 2<> . 32 . 35 1. 67 6.91 Kao linite , Ka o linite, - Quartz , Mus covi te ~7 . 35 .46 l. 54 9.73

All r; uilr t z n r e Al pha-Ouar tl. 1 Tablehol : XRD Oat a Locality Han:;~,aon (Kudal Taluka)

(6.535) Sr.No. e d-spacing Relative Remarks Intensity

l. 4.34 10. 17 2.61 llli te 2. 6.07 7. 28 9.80 Kaolinite 3. 6.75 6.55 3. 92 Microcline 4. 7.41 5.97 3.92 Microc line 50 9.92 4.47 2.94 Kaolinite, Illite 6. 10.38 4.27 89.85 Quartz

7. 11. 10 4.00 5.88 Microcline 8. 11. 51 3.86 18.95 Microcline 9. 11.94 3. 72 8. 16 Kaolinite

10 . 12. 09 3.67 4. 57 Illite

11. 12 .33 3.60 8. 16 Kaolinite, Microc line 1 2. 12.75 3.49 18.62 Microcline 13. 13.25 3.36 100.00 Kaolinite, Illite, Quartz, Microc line 14. 13 .67 3. 25 92.79 Microcline 15. 14.30 3.11 93.45 Kaolinite 16 . 14. 7 5 3.02 10.45 Microc line 17. 15. 04 2.96 14.37 Microcline 18 . 15 . 35 2.90 14.05 Mi c r oc line 19 . 16. 1 fl 2.76 2.94 Microcline 20 . 17. 08 2.62 3.92 Microcline, Illite Microcline 21. 17.40 2.57 4.57 Kaolinite, Mi c rocline 22 . 17.70 2.53 4.70 Kaolinite, Quartz 23 . 8 . 20 2.46 30.71 Kaolinite, Microcline 24. 18.77 2.39 4.05 Kaolinite, Microcline 25 . 19. 20 2.34 7. 18 Kaolinite, Qua rtz 26 . 19 . 68 2.28 32.67 Kaolinite, Microcline, Quartz 27. 20 . 08 2.24 11. 76 Microc line, I llite 28 . 20 . £5 2. 16 17.97 Kaolinite, Quartz 29 . 21. l g 2.13 28.10 Kaolinite, I llite, Quartz 30 . 22 . 85 l. 98 13.07 Ka o l inite 31. 24 . l 5 1. 86 6 . 53 Ka o linite, Qu a rtz 32 0 2 5. 00 l. 82 33.98 Kno lini.te , Qu artz 23 0 27.38 l. 6 7 13. 7 2 Kao lini te , Qua rtz ., 2 7. 6 7 1. 65 4.24 ~· 0 ~;J •J li n it c , l! J i t e , Qua rt z 2) . 29 . 92 1. 54 L3 . 19 ------·- ·

1 . ~ ~ - ( f\. I ~- ,r- .t - • 1 1.1 r· t. : . l.ocil l i ty

(5o649)

5 r . ~, ·' . d-spncin,: fh •l iltive Rt->lll it rk s Int e nsity

l. s 0 14 lOoOO 3 o95 Illite

2. 7 . I 3 7 0 l 7 4 0 ) I Kaolinite

3 . 7 . ') 7 6o46 II o29 Microc iine

" . II olll> 4.42 6. 21 Kaolinite 5 . I 2 . 1 11 4.24 33.89 Quartz

6o 1 2.~6 4.02 7.34 Microcline

7. l 3 . (J l 3.97 3.95 Microcl ine

8 . 3 .82 4.68 Microcline + Kaolinite

'J . I :. 0 I 3 3.66 :l2 . 03 Microc line 10 . 14 . % 3.46 19.48 Microcline

11. I 5 o') 3 3.34 100.00 Kaolinite + Quartz -+ Illite U. I 'i . rlO 3.28 22.59 Microcline

13 . 1 h . n I 3.24 77.95 Microcline

l b 0 l i 3. 18 14. 12 Illite

I 5o l 7 . l ') 3.02 18.64 Microcline

I 6. l 7 o '•U 2 .97 11. 86 Microcl ine

I 7 o I I o 'J ~ 2.89 6. 77 Mi croc line + lll i t e

1 h . I h 0 .lt > 2o84 4. 18

19. l K. 'J ,., 2. 7 5 5.60 Kaolinite + Microcline

20. :!() .U L 2.6I II. 29 Microcline , Illite 21. 2.56 3.95 Kaolinite, Hicrocline Kaolinite + Microc line n . l( l . 17 2 .52 3.38 9.60 Quartz 23 . 2 I o .lll 2o45 5.08 Microcline, Illite 24 0 L I o h >: 2o42 Kaolinite + Hicrocline 25. 21. .57 2. 32 5.08 Quartz, Ka o li nile 26 . 2 l. l I 2.27 16.94 n. 2023 6. 21 Mi crocline , Quartz Microcline, Illite 28. 24.4 K 2. 16 13. 55 19. 20 Kaolinite + Quartz 29. 24 0 )l 'J 2 ol 2 Kaolinite + Quartz + I llite 30. I. 97 9.03 --· ------

Al l llll,iil · ' " ' . \ ~jt!I ( I- 1/I J . ill/ . Table 6.1':1 XRD Data LocalitY Pat Red (Kudal Taluk11)

(S.376)

Sr.No. e d-spacing Relative Remarks Intensity

1. 7. 18 7. 15 53.76 Kaolinite 2. 11. 55 4.46 2.68 Kaolinite 3. 12.12 4.2& 39.24 Quartz 4. 14.45 3.58 51.60 Kaolinite 5. 15.48 . 3. 35 100 . 00 Kaolinite + Quartz 6. 21.00 2.49 4.30 Kaolinite 7. 21.33 2.45 21.07 Quartz 8. 22.06 2.38 4.83 Kaolinite

9. 22.40 2.34 5.91 Kaolinite 10. 23.07 2.28 17.20 Quartz + Kaolinite 11 23.57 2.23 5.91 Quartz + Kaolinite 12. 24.36 2.12 8.60 Quartz + Kaolinite 13. 26 . 84 1. 98 10.75 Kaolinite + Quartz 14. 29.44 1. 81 30.64 Kaolinite + Quartz 15. 32.32 1.67 6.98 Kaolinite + Quartz Kaolinite + Quartz 1& . 32.5& 1.66 4.30 Kaolinite + Quartz 17. 33.45 1.62 2.68

All Quartz are Alphii·Ouartz. Table 6.16 XRD aata. Locality Kasal, Taluka Kudal.

Sr. No. d-spacing Intensity Remarks Relative

1. 7.13 7.18 47.65 Kaolinite

2 . 11.62 4.44 5.70 Kaolinite

3 . 12.11 4.26 71. 18 Quartz

4 . 14.51 3.57 25.88 Kaolinite

5 . 15.49 3.34 100.00 Kaolinite, Quartz

6 . 20.41 2.56 2.94 Kaolinite

7. 21.34 2.45 17.06 Quartz

8 . 23.08 2.28 4.29 Kaolinite, Quartz

g . 23.58 2.23 4.70 Quartz

10 . 24.85 2.12 6.47 Kaolinite, Quartz

11. 26.87 1. 97 5.88 Quartz

12 . 29.46 1. 81 14.70 Kaolinite, Quartz 13 . 32.33 1. 77 3.82 Kaolinite

14. 35.46 1. 54 8.23 Kaolinite, Quartz 15 . 36.90 1. 48 2.05 Kaolinite

All Quartz are Alfa-Quartz. Table 6.1J, XRD Data Locality Tak 1 (Vengurla Taluka)

(5.55)

Sr.No. e d-spacing Relative Remarks Intensity

1. 7. 14 7.18 100.00 Kaolinite 2. 11.55 4.45 4.44 Kaolinite 3 . 11. 81 4.36 9.43 Kaolinite 4. 12.07 4.27 3.60 Kaolinite 5. 12.30 4.19 8.32 Ka o linite 6. 13.41 3.85 3.88 Kaolinite 7. 14.46 3.57 66.60 Kaolinite 8 . 15.49 3.34 2. 77 Kaolinite 9 . 20.40 2.56 6.10 Kaolinite 10 . 20.64 2.53 3.88 Kaolinite ll. 20.96 2.50 9.43 Kaolinite 12. 22.06 2.38 4.44 Kaolinite 13. 22.44 2.34 19. 14 Kaolinite 14 . 22.93 2. 29 7.21 Kaolinite 15. 23.94 2.20 2.22 Kaolinite 16 . 26.67 1. 99 5.27 Kaolinite 17. 32.45 1. 66 3.88 Kaolinite 18 . 33.35 1. 62 2.22 Kaolinite Tabl( ll.l'-. XR D Da La Locality Tak 2 (Ven ~o; ur1a Ta1 uka)

(5. 31

Sr.!\o. 8 d-spacing Relative Remarks Intensity

l. 7. 13 7.14 100.00 Kaoliuite

2 . l 1 . 57 4.45 5.31 Kaolinite 3 . I 1. 86 4.34 15.42 Kaolinite

4 . 12 .43 4. 15 20.21 Kaolinite

) . I 3. 15 3.93 2.65 Kao linite

6. I 3 . 50 3. 83 7. 97 Kaolinite 7 . 13 .84 3.73 3.98 Kaolinite 8 . 14.46 3.57 98.40 Kaolinite

C) , 14 .92 3.47 3. 72 Kaolinite

I U. 15 .4 () 3.36 6.91 Ka o l inite 11. 16 .47 3. 13 2.65 Ka o l inite 1! . 16 . 80 3.09 2.65 Kaolinite l l. 18.96 2.61 3.72 j.,. 20 . 4 'J 2.55 6.91 Ka o linite

I '>. 20 . 67 2.53 4 .25 Kaolinite 1l> . 21.04 2.49 7. 97 Kaolinite

I 7 . 21. 59 2.43 3. 19

1 "· . 22 . 07 2. 38 27.65 Kaolinite 1') . 22 . 50 2.33 18. 08 Kaolinite

2U. 22 . 97 2.29 10. 63 Kaolinite

L I . 23. 4CJ 2. 2 5 1. 59

. ' 26 . 6 ) 1. 99 5.85 Kaol inite ~ L '

.: ·. . .! t 1 . BU I. 98 5.85 Ka o linite Ka o linite ~ 4. '27 . 50 l. 93 3.98 Kaolinite 2 c., . 2 B. I S l. 89 3. 19 Kaolinite 2b . 2 9 . I 5 l. 83 3.72 Kao1 ini te i• 'l . 1U . OO 1. 78 12. 23 Kaolinite 2!:!. 31.00 1. 7 3 1. 59 Kaolini te :.!9 . 32 . 55 1.66 6.91 Kaolinite 30. 33.53 l. 61 5.05 Kaolinit• 3 1 . 34 . 35 l. 58 1. 96 1. Kaolinite l2 . 35. 35 l. 54 59 ------·

All ()\1 o r l L. a r e Alj,lw-Quar lL. Table 6.\Q : XRD nata I IIC illlty Mahapan (Ven11,urla Tnluka)

('i .J7L)

.> r. No . d-spnc in>; Relative Remarks In.tensi ty

1. 7.17 7. 16 15.96 l':aolinite

2. 7.91 6.49 2.68 Hie roc line 3. 11.61 4.44 3. 22 Kaolinite 4. 12. 17 4.24 31. 71 -Quartz, Hie roc line 5 . 12.40 4. 16 2.90 Kaolinite

6. 13. 10 3.97 4.83 Hicrocline 7. 13.55 3.81 2. 15 Microcline 8 . 14.03 3.69 2.95 Hicrocline 9 . 14 .4 7 3. 57 8.60 Hi c rocline + Kaolinite

10 . 1/o 94 .1 .46 4.56 Hicrocline

I I . IS. 53 3.34 100.00 -Quartz, Micn•c.. line, Kaolinite I 2. 15.77 3.28 11.98 Hicrocline 13 . 16.03 3 .24 50.53 Hicrcc line

11·. 17.30 3.00 2.68 Kao 1 in it e I 5. 17. 50 2.97 2.68 Hie roc line I G. 17. 97 2.89 6. 18 Hicroc 1ine

I 7 . 18. 87 2. 76 3. 8 7 Hicrocline

1 q . 20. t, 5 2. 56 7. 25 Hicrocline + Kaolinite l 9 . 21. 04 2.49 1. 7 2 Hicrocline + Kaolinite 20 . 21. 39 2.45 2. 79 - Quartz 21. 21.63 2.42 3. 76 ~licro c line Mi c roc 1ine + Kaolinite f. "l 22 . so 2.33 4.83 - Quartz + Kaolinite 1. 3 . 23 . 08 2. 27 5. 37 Mic r oc line 2 4. 23 . 57 2.23 6.98 Microc line 25 . 24 . 4 5 2. 16 4.03 Ka o linite + - Quart z :::, . 24. 138 2 . 12 4.30 Kao lini t e + - Qua rt z 26 . fl l 1. 98 3 . 76 9.40 K.:~o linite B . 29.46 1. 81 Ka o linite, -Quartz 29 . 3 2 . 31, 1. 6 7 3. 2 2 6 . 7 2 Kao linite, - Quartz. 30 . 35 . 45 l. 54

,\ l l l)ua rtz are Al pha-Ou;H t z . Table 6oXl: XRD Data Locality Adeli (V engur1a Ta1uka) ~ 6o250~ 12o195

SroNoo d-spacing Relative Remarks Intensity

l. 7 0 14 7o19 5o93 Kaolinite 2 0 7o94 6o47 5.62 Microc line 3 o 8.65 5.94 4.06 Microc1ine 4. 9. 12 5.63 3o43 Microcline 5. 11.62 4.44 4.37 Kaolinite 6. 12. 14 4.25 73.75 Quartz 7. l2 o98 3o98 14.37 Hicrocline 8 0 13o49 3.83 9o06 Kaolinite, Microcline 9 o 13 o96 3.70 9.37 Microcline 10 0 14 016 3.65 15.62 Microcline 11. l4o50 3. 57 5.31 Kaolinite, Microcline 12 0 l4o9l 3.47 23.75 Microcline 13 . 15.49 3.34 100.00 Kaolinite, Quartz, Hicrocline 14 0 l5o 76 3o29 21.87 Microcline 15. 15.98 3.24 93.75 Microc1ine 16. 16 . 45 3. 15 4.37 Kaolinite 17. 1 7. 19 3.02 6.87 Microcline 18 0 l7o59 2.95 14.06 Microcline 19 0 17o94 2.90 12.18 Microcline 200 18 .78 2.77 4o37 Microcline 21. 1Bo 95 2. 7 5 21.87 Hicroc1ine 2 2 0 19 o94 2.62 6o25 Hicroc 1ine L 3 o 20o 4 1 2 .56 4.50 Kaolinite, Microcline 24 0 200 71 2.52 3o43 Kaolinite, Hicrocline 25 0 21 o33 2. 4 5 16.25 Quartz 2ho 21 0 58 2.43 3. 12 Microcline L7 o 2 2 0 54 2 .33 4.37 Kaolinite, Microcline :ltl o 23 o07 2o28 14.68 Kaolinite 29 0 23 .54 2.23 12.68 Microcline, Quartz 30 0 24o45 2.16 15.62 Hicrocline 31. 24o 85 2. 12 15.62 Kaolinite, Quartz Kaolinite "J2 0 25 o20 2. 10 7 011 3 J 0 2':- o49 2 . 07 2.50 Kaolinite Kaolinite, Quartz 34 0 26o 84 1. 98 9.75 Kaolinite 3 5 0 270 62 1. 92 14.51 36 0 28 036 1. 88 5.48 J

. . ------·

0 I, I I ,, o 1 • 1 'l! 1 r t .- Tab I E> 1> .21 : XkO Data Locality Tulas ( Ve no.:ur l a laluka )

(5.747)

Sr. No. e d-spacing Relative Remarks Intensity

l. 7. I 5 7.17 42.52 Kaolinite

2 . 10.38 4.96 4.19 Illite 3. 11 . 56 4.45 5. 17 Kaolinite

4 . l 2 . 12 4.26 58.04 Quartz

r J . 1 2 . 41 4. 16 5. 74 Kaolinite

b . 14.04 3.68 5.49 Illite

7 . 14. 49 3. 57 32 .75 Kaolinite

b . 15.48 3.35 99.42 Kaolinite, Illite, Quartz

' ). 20. 41 2.56 9.19 Kaolinite 10. 20.91 2.50 7. 4 7 Kaolinite 11. 21.33 2.45 28. 16 Quartz

1 2 . 22.45 2.34 9.76 Ka o linite I 3 . 23.09 2 .28 25.86 Kaolinite, Quartz

1-. . 23 . 56 2. 2 J 21.83 Quartz

I J . 24 . 82 2 . 13 10.91 Kaolinite, Quartz

]() . 26 . 84 I. 98 21.26 Kaolinite, Quartz, Illite 17. 2Y.46 1. 81 100.00 Kaolinite, Quartz

1- . 32 . 32 1. 6 7 13 . 21 Kaolinite, Quartz, Illite

l 'J . ) 5.43 1. 54 32.75 Kaolinite, Quartz, Illite

•\ l I f.H l {t r t I a rr: AIJ >ha - Quartz. T -. h 1 <' (,. :'~ : \R!l On to l.oc Ality l. rASW!H)i . (Ve n~;ur1n T11lukn )

(6 . 060 )

Sr. No . d-spacin~ Relative Remorks Inte ns ity

1. 6. 12 7.22 6 .66 Kno I i n it e 2. 6. 77 6.53 4.84 Hicrocline

3. 9.94 4.46 3.03 Kaolinite

4. 10.41 4.26 86.65 Quart z

5 . I 1 . l 5 3.98 10.30 Hic r oc li nc 6 . 11. 57 3 .83 20.60 Kao linite

7. 11.97 3. 71 11. 51 Hicroc line 8 . 12. 35 3.60 6.96 Kaolinite, Hicroc line 9 . I 2. 77 3.48 15. 15 Hie roc line 10 . 13.28 3.35 100 .00 Kaolin ite , Quart z , Hie r oc I ine 1 1 . 13 .47 3.30 7. 27 Hicrocline

12. 13 . 67 3.25 78.78 ~1 i croc li ne

I 3 . 13.88 3.21 6.36 Kaolinite

14 . 14. 33 3. 11 13.33 Kaolinite 15 . 14 . 60 3.05 9.39 Hi c r oc line

J 6 . 15 . 05 2.96 9.69 Hicroc line

1 7 . 15 . 35 2.90 9.69 Hic rocl ine 18 . 16. 19 2.76 6.66 Hicrocline

l 'l . 17 . 08 2. 62 4.24 Hie r oc line

2U. 17 . 43 2.56 6.06 Ka o linite , Hi c r oc line Microc line 2 I . 17 . 73 2. 52 4. 54 Kaolinite, 22 . 18 . 23 2.46 36.96 Quartz Kaolinite , Microcline 2l . 19 . 23 2.33 7. 8 7 Kaolinite, Quartz 24 . 19 .70 2.28 24.63 Hi crocline, Quartz 2 j . 20 . 10 2. 24 10.90 Mi c rocline 26 . 20 . 85 2 . 16 18 . 18 Kaolinite, Quar tz 27 . 21. [ 9 2. 13 22.72 Kaolinite, Quartz 28 . 22.87 l. 98 11. 51 20 , 23 .54 l. 92 5. 15 Kaolinite Kao linite 30 . 24 .41 l. 86 5. 15 Kaolinite, Quartz J l. 25 .03 l. 82 48 .48 Kao linite , Qua['tz " ' 2 7 . 41 l. 6 7 2 1. 2 I 26 . 0) Kao linite, Quar t z ~. .) . 29 . 94 l. 54

1\ I 1 l) u;,~t7 ore .AI ph:1-Quar t z . Table 6.22 (a) Value of characteristic X-ray diffraction Maximum lines in Angstroms (~) of claya From Sindhudurg District

Taluka Locality Treatment Remarks ------None Ethylene Glycol Heat at 55o•c for 2 hours ------X-ray diffraction Maxima in Angstroms

Kankauli Harkul 7. 14 3.35 7.15 3.57 D.R. Kaolinite Mal van Kum 2 a. 7. 10 MT 3.57 7.10 MT 3.57 D.R. Kaolinite b. 9.90 4.96 9.91 4.96 9.89 4 . 95 Illite Kum 3 a. 7. 16 M1 3. 57 7 .16 M1 3.57 D.R. Kaolinite b. 9.90 4.95 9.90 4.95 9.91 4.96 Illite Kudal Kasal 7. 17 M1 3.56 7. 17 MT 3.56 D.R. Kaolinite Ven gurla Tak 7. 14 MI 3.56 7.12 MI 3.55 D.R. Kaolinite

Tak 2 7. 15 MI 3.57 7.14 MI 3:57 D.R. Kaolinite Mahpan 7.16 MI 3.56 7.16 MI 3.56 D.R. Kaolinite Sawantwadi Talavade 7. 15 MI 3.57 7. 17 MI 3.57 D.R. Kaolinite Otavane 7.16 Ml 3.57 · 7.16 MI 3.57 D.R. Kaolinite

D.R. Disappearance of all reflections. M. I . Most Intense. 12 2

Sepolite is the other mineral seen in these samples.

The qualitative presence of clay minerals in clays from five talukas o f Sindhudurg distr ict can b e summarised as fo llows :

Mineral Kudal Vengurla Kankauli Mal van S .Wadi ------Kao linite +++ +++ +++ +++ +++

I llite + + + + +

Microcline(KFS) ++ ++ + +

Sepo lite + i'lu scov i t e ++

Quart z ++ ++ ++ ++ ++

+++ Dominantly occurring

++ In moderate amounts

+ Little amo unt

Absent.

I nfrar ed spectroscopy :

Though X-ray analysis is more sensitive to the periodic a rrangeme nt of the atoms in a crystal and the rmal analysis to the strength of decomposition of the bonds b e tween the various atoms and the atom g roups in certain crystals, these 123

techniques are often supplemented by IR analysis for i nvest i ga tion of c lay minerals.

In 188 1, Abney~Festing published 52 absorption spectra o f compounds. Julius (1892) was the first to suggest that the character of absorption is determined by the atoms present and the way in which they are linked. Coblenta

( 1905 , 1906, 1908) published a collection of infrared absorption spectra mainly of organic compounds. Herzberg

( 1950) has given theory of mo lecular spectroscopy in greater detail and his work forms the basis for assignment and correlation of bands in the spectra. Pioneering work on infrared spec troscopy in mineralogy is by Keller and Pickett

( 1949 , 1950) , Milkey (1960), Stubican and Roy ( 1961) , Farmer and Russel (1964), White and Roy ( 1964). As the number of publications dealing with infrared increased, the data was published ln a book form edited by Farmer in 1974 as a

Monograph of Mineralogical Society of London. Gadsden

( 19 75) published data on minerals and related inorganic compound s in a numerical form, which helps easier iden tification. 'Atlas of infrared spectroscopy of clay mi nerals and their admixtures' (van der Ma rel and

Bo ute lspacher, 1976) gives a complete information ln a 124 graphical as well as numerical form of the several clay minerals of varied origin.

IR spectroscopy help in studying the compositional and s tructural variations in minerals, ionic substitutions, quality and quantity of water, differences in atom ordering e tc. Infra red spectroscopy also helps in distinguishing between the polymorphs of minerals. As compared to X-ray and D.T.A., only few mg of sample is required for IR a na l ys is. Because of a ll these me rits, in r ecent years IR me thod is widely used in qualitative and quantitative es tima tion of clay minerals and their admixtures.

Analytical method :

In the present study , about 20 clay samples from diffe rent localities are subjected to IR analysis on Perkin

El mer 337 a nd Pye Unicam PU 9512 in Ch emistry Depa rtment of

Poona University. About l to 2 mg of sample was mulled in one drop of a n inert liquid Nujol and it was mounted on K Br p l a t e s . As Nujol was used , some e xtra bands we re added. I n -1 the first phase of run, the frequenc y was between 1200 em to

4000 cm1 while in the lind phase, frequency was between 400 cm 1 a nd 1300 ern ~ Th e wa veleng th range wa s be tween 2 t o 2S tUm. 125

The standardisation was done using polystyrene film at 1603 c ml and at 3061 em~

Assignment ~ Infrared bands :

In the infrared technique, the radiations absorbed by a s ubstance is plotted against the incident wavelength or frequency and the graph obtained is interpreted in terms of i nt e rmolecular vibrations. This graph is characteristic of the material and can be used in its identification. In the i n fra r e d spectrum, every band should be assigned to a pa rticular vibration . This is comparatively easy for simple mo l ecules like H2o, co 2, Sio 2 etc. But in more and more comp licated structures, it is controlled by many factors like masses of atoms, their distances, symmetry, bond s tr e ng th and dipole momentum during vibrations, particle s1ze , wave length and the difference in refractive index between the absorbing substance and the dispersion medium.

Broadening of bands, loss of intensity and decrease of frequency are caused by isomorphous substitutions and poor crys tallinity of the analysed substance. The characteristic 1 freq u e ncies mainly fall in the region 3500 - 3750 cm and -l 400 - 1150 em. 126

Buswell and Dudenbostel (1941) first showed that the absorption in the reg ion 3500 - 3750 cm 1 is due to h ydroxy l g r oup . Serrato sa ( 196 2) stated that the absorption f reque ncy of 0 - H band depends on the degree of association of these g r oups. For free groups the frequenc y is around

3700 em~ With increasing association, the frequenc y decreases d epending on the streng th of the h ydrogen bond.

Structural OH gr oup shows the frequency in the range of 3600

- 3700 c~ 1 whereas absorbed water shows lowe r frequency at

3400 em and another at 1640 em.-1 The first i s streching mo d e while latter is deformation mode.

I n the region of 400 to 1500 em,-1 the frequencies are d u e to lattice vibrations. In this range, the l ayered silicates 1n which aluminium for silicon substitution is a bs e nt or low, g ive the sharpest spectra. Infrared spectra o f silicates are dominated by the strong a nd broad band in -] the r a nge 1200 - 800 em due t o Si - 0 b e nding and a broad, -1 me dium absorption between 2400 - 2320 em r epresenting a harmo nic of Si - 0 streching . Within the silicates, the

freq u e ncies of Si - 0 streching bands decrease a s the Si/0 mo l e r a tion decreases indicating a decrease in the bond

e n e r g ies systematically from tectosilicates t o

nesosilicat es . 127

Vibration s in the r egion 550 960 crrJ c a n be a ttributed toR- OH bending vibrations. Strong vibrations in the reg ion below 550 c~ 1 a rise principally from in p lan e vibra tions of octahedral ions a nd the ir adjacent o xygen l aye rs . The presence of Fe , Mg r e placing Al causes a s hift from high e r to lower fr equenc ies but however the s ubs titution in t e trah e dra l si t e does not af f ec t these a bs o r ption bands.

Charact e ristic bands of some minerals

Kaolin it e has strong bands a t 3694 , 362 1 , 110 0 , 1032 , -1 l 008 , 9 1 3 , 694 , 539 , 471 and 431 em . How ever the positions and intensities may vary from sample to sample. Halloysite , which has a more disordered structure, shows wide variations

1n freq u encies and inte nsities. The most useful bands are s een a r ound 3695 , 3623 , 1094 , 1033 , 1012, 913 , 692 , 540,

4 71, 432 em: Th e well ordered mine rals of thi s group dicki t e a nd nacrite have similar s pectra , have bands at around 362 7 , 3622 , 1117, 1002 , 913 , 796, 754 , 693 , 608 , 469 a nd 4 29 cm 1 a nd it is rather difficult to dis tingui sh be t vveen the tvJo . 128

Strong bands of illite occur at 3643, 3622, 1166, -] 10 0 , 1022, 534, 52 3 a nd 475 em:

In case of the mixed l ayer mineral s, the spectra shows enhanced charac t ers of the dominant minerals. \\leaker bands o f the mineral, whose layers are in lesse r amount, are eliminated .

Amon gst the feldspars, plagioclase feldspar shows the strong spectra at 11 43 , 1082, 1020, 932 , 757, 625, 578, 543 , -l 470 and 430 em. while alkali feldspars show the bands at -l 1130, 1008 , 645 , 590 , 544 and 430 em.

Quartz has strong bands at 1172, 1082, 798 , 77 8 , 512, -] -l -1 478 and 460 em of which the doubl e t at 79 8 em and 77 8 em ma kes ide ntification of quartz from mixtures ve ry easy .

Based on these observations , the infrared spectra of c lay samples from the present area [ Fig . 6 .1 (a), 6.1 (b),

6 . 1 (c), 6.1 (d) ] were studied and the association of mi ne rals and their relative abundance s were de t ermined.

1 . Kankauli Ta luka : IR s pectra of c l ay samples from Kankauli taluka - l e xhibits frequencies in the range of 3600 3700 em 1.-

K : KA OLINITE

~ • QUART Z PI • PLIGIOC LAS E

SAWANT\VADI 2

K K

K

- ·3500 3000 2500 2000 1500 1300 120 0 1100 1008 900 BOO 700 600 500 F requency ( Cm1 J Flg.6 -1a·. IR Spectra of clay samples from Sawan1wadi Ta!uka . f\ ' KAOLINIT::: Q • QUARTZ II

Q K KANKAULI ( Boring ) K

K

HARKUL

KA.NKAUL!

K

15{:() 1200 1100 1000 900 BOO 700 600 500 . ·3500 3000 2500 2000 1300 Frequency ( C ml Fg-6 ·1 b:lR Spectra of clay samples .from Kankaul·l Taluka. KU M SHARM A TI I PI • P LAGiOCLASE K• KAO LI NITE I ~.q U ARTZ ,I. !

K MAL VAN Pi

JANULI

V'f\ t{ G K I ~ ' KANKAULi

~~~~/'\{\ q . K q \./'-- K K Q

3500 3000 25tJO 2000 1500 13:)0 1200 1100 1000 900 600 700 GOO 5 0 0 Fr~?quency(Cm1) F1·g. 6·1b: I R Spectra of clay samples from Mal van and Kankauli Talukas. K ' KAOLINITE Q. , ({UAR T Z

PAT 2

q QK K

Q K n \ KASAL

3500 3000 2500 2000 1500 1300 1200 1100 1000 900 800 700 600 500 F requency ( Cm1) Fig.6·1c : IR Spectra of clay samples 1rom Kudal Taluka. ~. 'KAOLINITE I Q• QUARTZ, KD· KAOLINTE DICKITE, CI.CHLORITE, PI · PLAGIOCLASE

MHAPAN

VENGURLA "1 KD I I GRAS- I ( ~' WADI l_j/ .., -- I KD ( i I I . I \u I G V&JGURL..A I K

3500 XXfJ 2500 2000 1500 1300 120:· iiOO 1000 900 800 700 600 500 Frequency ( Cm 1 Fig . 6 ·1d: I R Spectra of clay samples from Vengur!a Talu ka.

------·------··- -- K : X..l.OLINITE, Q QU ARTZ, KO, XAOUNITIC OIC~1-:-:=:, TALA VADE Pl , PLAGIOCL..l.SE, Ci • CHLORITE _ \;' )\

K Q_ K 'r\

TAK 2

A DE L! ~ xq K w ~ ?

TULAS

K Q X Q K

3500 3000 2500 2000 1500 1300 1200 1100 1~00 900 900 700 600 500 Frequency ( Cm l ) Fig · 6 -1d: IR Spectra of clay samples from Vengurla Taluka . 129

indicat i ng the presence of Kaol inite. In on e sampl e , sharp a nd s trong band of Kaolinite is observed while in o thers the band is of moderate inte ns ity . Pre s e nce of broad, and mode rate bands at 1630 cm 1 in almost all samples indi cate -l the presence of deformation mode of 0 - H. 3400 em frequency th band is almost absent . I n the r egi on of l ow -l frequ ency range , a broad band of 980 - 100 em the poss ibility of the presence of kaolin, quartz a nd alkali fe ldspar can be interpreted . In the l ower fr e quency range, 1 abs ence of 430 cm band indicates l ess or no r epl acement of - 1 Al by Fe o r Mg in the octahe dral si t e . Sharp band at 460 em -l and doublet at 785 - 810 em is indicative of the pres enc e of quart z . Presence of kao linite also shows a ve r y s trong -l band a t 540 em .

2 . Kuda l Taluka : - 1 The fr e quency range of 3500 - 3700 em sh ows high to mode ra t e intensity of kaolinite a t the frequenc y of 3635 em] and 3710 em .

Mos t of the sampl es show the prese nc e of a b sorbed wate r -1 with a b r oad and mo d e r a t e band a t 1630 em a nd also somewh a t -l weaker band a t 3400 em. 130

In the ~ower f requency range,the presence of sharp -1 -1 -1 bands at 915 em and broad bands at 540 em and 470 em indicate the presence of kaolinite.

-1 Quartz doublet is present at 780 - 800 em.

3 . Ve ngu r l a Ta luka :

Mos t o f the samples show very strong and sharp bands of -1 kao linite in the higher fr equency reg ion of 3500 - 3700 em.

Pre senc e of H o i s indica t ed by mod e rate and broad bands at 2 1630 c~ 1 . A weak band at 3430 c~ 1 in most of the samples 1 a nd the nature of the band at 3500 - 3700 cm is suggestive of the presence of small amount of illite or montmor illonite a long with kaolinite. In the middle fr equency region, the 1 broad spectrum at 980 - 1100 cm show the presence of quartz, kaolinite and alkali feldspars. IR spectrum in the lowe r mos t f r e que ncy r ange show the bands a t 430, 47 5, 540 ,

690, 910 em-1 indicating abundance of kaolin.

Quar t z a nd f e ldspar a r e pre sent in small quan tity .

4 . Sawantwadi Ta1uka : -1 Kao linite peak at the freq ue ncy at 3500 - 3700 em show - 1 low to mod e rate absorption. Th e ba nd a t 1630 em 1s of 131

mode r a t e intensity and broad. Only one sample shows the -l pre sence of 3420 em band. Two samples sho\v sharp -l absorption band at 470 and 540 cm 1 and a weak band at 430 em

c haracteris tic of kaolinite. A broad band of Kaolin and K-

feldspar is seen at 1010 and 1035 em~ Quartz is nearly absent.

5 . Malvan Taluka :

Only one sample was analysed which shows the presence

of Kaolinite, Quartz and alk-feldspar. The IR spectrum

shows a sharp band in the region of high frequency which is -1 characteristic of Kaolinite. A strong band at 1637 em -1 shows the presence of adsorbed water. Bands at 475, 545 em are characteristic of Kaolinite.

-l A doublet of quartz is at 795 - 815 em. Thus it can be

concluded that the clays from Malvan (sample Kumbharmatt),

Ve ngurla (sample Tak), Kudal (Pat) and Kankauli (Harkul)are

much more richer in Kaolinite content, as compared with clay

samp l es from Sawantwadi taluka. 13?.

Therma l Analysis :

Th e rmal analysis is an important suppleme ntary technique in material characterisation. The different me thods of the rmal analysis a r e increasing l y us ed in various disc iplines of scienc e and technology . Th~are employed in de termination of thermal constants, calorimetric rr,eas ur emen ts, reaction kin e tics, phase studies etc. In

r1i nera logy the thermal methods are used in determining \Jater

c r vo latile content, crystal chemistry , chemical

cotnpo sition, degree of ordering, mineral transformation,

e tc. and as a supplementary technique of mineral

identifica t ion.

The earliest mention of the use of thermal analysis in

th~ identification of minerals is found in two volumes by

Ki rwan in 17 94 and 1796 (in Mackenzie, 1957). Le Chatelier

~ e ll known physicist developed the thermocouple with which

a cc urate t empe r atur e measurements were possible. He ge ts

th e credit of ob taining the first thermogram a nd o pe ning a

The first studied sample was a clay, and since

t h e n, th e the rmal methods have an important place in geology

a nd c l ay analysis. Wallch (1913) and Fenner (1913) we re the

pior1 eer wo r kers in applying thermal analysis to clays and 133

s ilica minerals. Contributions by Orcel (1926), Norton

( 1939) , Calliore and Henin (1947), Kerr and Kulp (1948) have been very useful in the development of the rmoanalytical me t hods as an important technique in clay geo logy.

Mine ralogical Society, London, has publishe d a vo lume 'The diff e rential thermal investigation of clay' under the edi t orshi p of Mackenzie in 1957. Later, (1970), (1972) und e r the editorship of Mackenzie two v olumes covering several aspects of thermal analysis appeared.

Smykatzkloss's (1974) 'Thermal Analysis' is of immens e us e t o a \vo rker using thermal analysis in mineralogical studies.

There are several thermoanalytical methods used in mineralogy based upon the fundamental properties of minerals which includes, weight change, energy change and dimension change in response to increasing t emperature . Th e mo st commo nl y used methods are, Differential thermal analys is

(DTA) , Thermogravimetry (TG), Derivativ e the rm ogravime try

(DTG) , and Dialatometry. In the present work differential the rmal a nalysis and thermogravimetry have us ed for ide ntification and quantitative es timation of kaolinite . 134

Differential thermal analyses :

The method of differential thermal analysis determines, by suitable apparatus, the temperature at which thermal

reactions take place 1n a material when it is heated

continuously to an elevated temperature, and also the

intensity and general character of such reactions. In the

case of the clay minerals, differential thermal analyses

show characteristic endothermic reactions due to dehydration

and to loss of crystal structure, and exothermic reactions

due to the formation of new phase at elevated temperatures.

The method is, therefore, useful for clay mineral researches

a s a means of studying high-temperature reactions, in

a ddition to its value in the investigation of hydration phenomena.

Differential thermal results are plotted in the form of

a continuous curve in which the thermal reactions are

plotted a gainst furnace temperature s, with endothermic

r e actions conventionally shown as downward deflections and

exothermic reactions as upward deflections from a horizontal

base line. The amount of divergence of the difference curve

fr om the bas e line reflects the diffe r ence in temperature

b e t we en the sample and the furnace at any g iven temperature 135 a nd i s the refore , a measure of the intensity of the thermal r eaction.

The endothermic reaction between about 500°C and 700°C corres ponds obviously to the dehydration of the mineral. A comparison of the curves illustrates that the differential me thod is a dynamic rather than a static one. The thermal

reactions are not instantaneous, and they are recorded as

f unctions of time or as functions of the furnace

t empera ture, which is continuously increasing as the

reaction takes place. The temperature at which the deh ydration begins corresponds to the start of the e ndothermic reac tion. The temperature of the peak of the e ndoth e rmic deflection varies, depending on the details of

the procedure followed, the character of the reaction

invo lved, a nd the material being studied.

Though DTA can quickly identify the pres e nce of small quantiti es of specific impurities but it may not b e consid ered as a 'finger printing' technique as X-ray

d i ffrac tion. In practice while evaluating the DTA curves,

it i s obse r v ed that there are s everal factors that influence

the DTA data, such as furnace atmosphere, sample 136

arrangement, type of thermocouples, heating rate, reference material, difference in the specific heat, heat conductivity and volume of starting material, inert substance used and reaction products, grain size, crystallinity, packing density, amount of sample in a mixture, sample preparation e tc.

Size of a peak in DTA depends on the amount of current that is developed which ultimately depends upon the energy of reaction. Mass of the reacting material is approximately proportional to the area under curve. The peak temperature depends upon the amount of reacting material in the sample. These facts are used in the quantitative mineralogical work using DTA.

Thermogravimetry (TG) :

Changes produced in the weight of a sample when heated are recorded in this method. These changes may be loss in weight which is more often - due to loss of water or some volatile component or gain in weight due normally to oxidation while heating. TG curves do not give much information besides the percentage we ight l oss and its t emperature range. 137

Simultaneous recording of DTA and TG curves helps in distinguishing crystalline transitions, second order transitions and solid state reactions which occur without any weight change from those involving dehydration or loss of volatiles which ultimately cause a change in weight.

Such recording facilities are available with some of the modern equipments.

Two closely following reactions involving weight loss g ives an unreliable TG curve and the evaluation also becomes cumbersome. Similarly, if there is a mixture of components in the samples, such as clays and iron oxides, the temperature ranges of weight loss of clays and oxi dation

(weight gain) of iron oxides being overlapping g ive an inaccurate pe rcentag e of water loss. The 'steps' of weight loss are r a rely sharp and it becomes difficult to decide the precise t emperature range during which the weight loss has occurred.

In the following pages, the thermal characteristics of the frequently occurring clay minerals and their common a ssoc iate s are d e scribed in brie f. 138

Kaolin minerals :

The generalised DTA of kaolin minerals shows four peaks, three endothermic and one exothermic when heated to 1000° C. The first endothermic peak that occurs above 100°C of varying shape and size is associated with some weight loss on TG curve. It is characteristic of halloysite and allophane and may be very small or even absent in other kaolin minerals. This may be attributed to sorbed water on the surface or interlayer water or to the water associated with amorphous silica and alumina gel.

The second or the main endothermic peak occurs in the t emperature range 500°C to 600°C. The peak temperature, symmetry and size of this peak have been used in characterisation of kaolin. This peak is due to the loss of wa t e r in the lattice. A corresponding weight loss is seen in TG curve.

A third very small endothermic peak is shown by some sample s having high degree of crystallinity a round 930° C just before the first exothermic peak (Grim, 1947).

According to Holdridge and Laughan (in Mackenzie , 1957) this peak is due t o the decomposition of poorly orde r ed compound 139

( resulting as a product of main endothermic reaction) into amorphous alumina and silica.

One exothermic peak occurs in the range 950°C to 980°C that forms the characteristic of this group. The peak temperature is higher in more ordered crystals. The magnitude of this peak varies with the particle size, and degree of disorder. Small particle size and higher disorderinb give a small peak. This peak is probably due to the breakdown of the kaolinite structure and crystallisation of a spinel phase (Smykatz-Kloss, 1974). This exothermic peak is modified by the presence of Na+ and other inorganic compounds also. Saunders and Giedroys (1950) have shown that the peak temperature is considerably lowered or even the peak may be completely suppressed by the presence of iron compounds.

Dickite : The first endothermic peak of kaolinite is absent. The main endothe rmic peak is at a higher temperature than kaolinite, is asymmetric and broader than halloysite.

Exothermic peak occurs at 980°C. 140

Nac rite :

The first and the third endothermic peaks of kaolinite are absent. The main endothermic peak occurs at a lesser

temperature than dickite, and the exothermic peak is around

980°C .

Kaolinite T :

In this, practically all the water loss occurs between

4 8 5°C and 540° C. The first endothermic peak is feeble. The

second one is large and occurs around 600°C. A peak in the

100°C to 200°C range suggests a finer particle size. The

main endothermic peak is highly symmetrical with slope ratio

nearly equal to 1.0. Sharpness of this peak suggests finer

particle size and also a limited size range. Exothermic

peak is sharp.

Kaolinite M :

In contrast to the DTA curve of kaolinite T, the curve

for Kaolinite M shows the first e ndoth ermic peak distinctly,

the main endothermic peak is at a lower temperature, sharper

and more asymmetric. The exothermic peak is smaller. The

degree of disorder in stacking of sheets in differe nt

sampl es causes variation in the curve in general. 141

Halloysite 2 ~ A small endothermic peak occurs from 100°C to 200°C with a maximum at 150°C. The main endothermic peak is at

600°C and has a higher slope ratio. The exothermic peak is at 980°C. The size of first peak varies with the degree of hydration.

Halloy site lQ ~ In the fully hydrated form the first endothermic peak

1s as large as the main endothermic peak. All peak t emperatures are lower by about l0°C, suggesting that interlayer water causes an increase in the degree of disorder. Halloysite shows a sharp loss in weight around

50°C, a steady weight loss between 250°C and450°C and again a sharp weight loss between 450 °C and 500°C (Nutting, 1943).

Bramac et.al. (1952) suggest that the peak asymmetry in halloysite is due to a shoulder present at a slightly lower

temperature than the main endothermic peak. This shoulder is due to the loss of weakly bound hydroxyls in the structure. The slope ratio of this peak is used to distinguish this mineral from kaolinite. In kaolinite, this ratio is between 0.78 and 2.39. Churchman and Carr (1975) have also suggested that the DTA characteristics can be used

in distinguishing halloysite and kaolinite. 142

Allophane : A large endothermic peak and corresponding weight loss below 200°C, distinguish allophane from other kaolin minerals.

The first endothermic peak is significant in the DTA curves of the minerals in kaolin group. If it is large, it suggests allophane or halloysite, if smaller, partially dehydrated halloysite, and if very small then it is a mineral with little disorder or finely divided kaolinite T. Absence of this peak suggests coarse grained kaolinite or dickite or nacrite. Kaolinite has a peak temperature of the main endothermic peak about 70°C to 90°C lower than dickite and nacrite.

In the present study thermal dehydration and decomposition behavior of about 16 clay samples from 5 talukas from Sindhudurg district were studied using STA 781 system for recording DTA and TG curves. The samples analysed were ground in agate mortar and were then loosely packed in l gm. capacity crucible. Pt/Pt-Rh thermocouples were placed at the centre of the sample and the samples were

then heated upto a temperature of ll40°C at the rate of 20°C / minute. The inert material used was calcined alumina. 143

The observations from the DTA curves obtained from the clay samples belonging to different talukas are described in the following paragraphs and are represented in Fig . 6.2

( a ) , 6 . 2 (b), 6.2 (c) and 6.2 (d).

Sawantwadi Taluka :

The main endothermic peaks occur in between 557° and

and are of moderate intensity. In the lower temperature region is below 400°C the endothermic peaks are a lmost absent indicating the absence of sorbed water and

Halloysite . The main endothe rmic reaction starts at about 460 ° C and ends at about 680°C. In the sample from Otavane, t he exothe rmic reaction occurs at 1009 C and indicated by the presence of sharp peak. The reaction starts at 977 °C and In other clay samples from Sawantwadi t a luka , the e xothermic peaks are broad and shallow.

Kankauli Taluka : The DTA curves show main endothermic peak within the range of 55 7°C with 566°C which are broad a nd shallow. Two sampl e s show small endothermic peaks below 400 °C. The exo the rmic peak is absent in one sample and in other two TAL VADE 1005°

NEMALE

985 °

TG

SAWAN T WADI IG 1050 °

OTAVANE

1000 °

1000 900 800 700 GOO 500 4 00 3 00 200 100 ° c Fig. 6· 2a: DT A, TG curves for clay samples from Sawantwadi Ta/uka. ., tvtr\CV'AN '' f ., ,,

1022 "c

TG - -- ~ ··

-~ 5B1•"c _1

J/\NUl.l 517" c

%9 "C ~' - · ~- - .

SG3''c

H/\flKUL

IG -----

.__ _,_____ .. _ _ ------' ·------· ·-.t...... - ...... _ _1 "- · - - J .. ·---.1-_J.______L______. 1000 !100 t\00 lOO GOO 50 ~ 1 LOO 300 200 100 ° C Fig G · 2b : D TA ,TG ctnves for ci;Jy s:Jmples frorn I< ;J tll< a u Ii ,J IHI H a I vZlll ·lj Iu l< ~ s . MANGAON

KASAL

TG

1000 soo soo 700 600 soo t.oo 300 2oo 100 oc . Fig.6·2c ·. DTA, TG curves for clay samples from Kudal Taluka ------

ADELl 969 ° ~

fULAS ~~v- 1007 °

5570

MHAPAN 1007°

TG

VENGUnLA TG / ------~

lCOO o

~57"

1000 900 800 700 600 500 '· 00 300 200 100 ° c Fig- 6 ·2d : orA, TG curves fo r c fay sarnples from Vengurla Ta/uka. TAK

1022 °

1000 900 ~00 700 GOO 500 400 300 200 1 00 °C Fig.6 · 2d ·. DTA ,TG curves for clay sample ·from Vengurla Taluk .:~ 144

samples small peaks occur at the temperature of 969 0 C and

0 • 985 C respect~vely.

Malvan Taluka :

One sample analysed from Kumbharmatt in Malvan taluka sh ow s almost a smooth curve till 400°C and the major

e nd o thermic reaction starts at 460°C and ends at 670°C.

Wi th the maximum intensity of the peak at 584°C. A sharp endo thermic reaction occurs at 1022°C.

Kuda l Taluka :

In Kudal, the DTA curves of 3 samples show the presence

of maJor endothermic peak at 557°C, The reaction occurs within the temperature range of 460°C to

Two samples show small endothermic peaks below 400°C , while in one sample sharp exo thermic peak occurs at

Ve ngurla Taluka :

Out of 5 samples analysed from this taluka, only one sample sbows very strong endothermic and exothermic peaks at

584°C a nd 1022°C respec tive l y , while in o ther sampl es , the

main endothermic reac tion occurs a t a slightly lower 145 temperature is l0°C to 30°C below. Similarly the exothermic reaction is either absent or is less intense.

On the basis of the above observations, it is clear that in most of the samples, the dehydration curves are almost flat upto 400°C showing little loss of water at low temperatures, while differential curves for some poorly crystalline kaolinite show a small endothermic reaction indicating the irregularity in the arrangement of kaolinite unit or the presence of small quantity of sorbed moistures in clays.

The ma jor endothermic peak of diffe r e nt intensities occur 1n all samples within the t emperature range of 557°C to 584°C indicating the presence of kaolinite. The r eduction in peak tempera ture to 557°C in some samples and also the reduction in intensity of reaction is probably due to the decrease in crystallinity and particle size of kaolinite. According to Grim shaw e t.al. (1945) the peak t empe rature is 20°C to 30°C lower for poorly crystalline kaolinite than for the well crystallised variety. This endoth ermic reaction around 600°C is a ttributed to loss of

OH mo l ecule due to breaking of kaolinite structure . At this 146

temperature, formation of metakaolin takes place and the energy is sufficient enough for cation migration.

The DTA curves of clay samples from Sindhudurg district show that the exothermic reaction, in most cases is between l000°C to l022°C while in some cases it occurs at 20°C to

30°C lower temperature than this. This reaction is possibly due to the break down of Kaolinite structure and crystallisation of spinel phase (S~ykaftz-Kloss, 1974). A sharp and strong peak at l022°C in the sample from Tak

Vengurla taluka, Kumbharmatt Malvan taluka probably indicate the formation of mullite.

TG curves :

In 9 of the clay samples from 5 talukas of Sindhudurg district, TG curves were simultaneously recorded with DTA curves in order to study the percent weight loss. The TG curves [Fig. 6.2 (a), 6.2 (b), 6.2 (c), 6.2 (d)] show weight loss in two stages. First stage occurs between l00°C to 400

°C, where the weight loss is very less is about 0.32 to 5.00 and is due to the loss of sorbed water and other volatile constituents. During the second stage, where the major endothermic reaction occurs, the weight loss is about 2.92 147

to 13.25. This weight loss is due to the structurally bound OH molecule present in Kaolinite. The weight loss after this maJor endothermic reaction is almost constant. The details of the percent weight loss at different temperatures are summerised in Table 6.23

Quantitative estimation of Kaolinite :

A method for quantitative estimation of Kaolinite is proposed by Carthew (1955) regardless of the degree of crystallinity and particle size using the relationship between area, width and slope ratio of endothermic peak at

In the present study the empirical relationship

Ratio A/W (measured from peak) 100 X X 0.8 gms. Ratio A/W (read from Fig.6.3 ) given by Carthew (1955) was used for quantitative estimation of Kaolinite. The areas of the major endothermic peaks of the differential thermal curves were measure d by planimeter.

The shape of the endothermic peak was determined by measuring the ratio of the slope of the low temperature to high tempe rature sides of the peak, and the width of the Table &.23 Percpnt weight loss at different temperatures calculated from TG curves for clay sample From Sindhudurg District

Temperature Kankauli Mal van Kudal Taluka Vengurla Ta 1uka Sawantwadi Taluka in °C Ta1uka Ta1uka Harku1 Kumbhar- Kasal Hangaon Mahpan Vengur1a Otavane Nema1e S.Wadi matt.i-

50 0.17 0.18 0.26 0. 17 0.13 0.16 0.19 0. 34 100 0.66 0.36 2.63 0.67 1.32 0.32 0.44 0.77 0.40 150 0.83 0.36 3.29 0.84 1.64 0 .49 0.58 0.94 0.50 200 1.10 0.36 3.68 1.00 1.99 0.57 0.63 1.07 0.60

250 1.24 0.45 3.95 1.09 2.15 0~65 0.69 1.19 0. 70 300 1.65 0.53 4.47 1.34 2.92 0.81 0.88 1.36 1.01

350 2.15 0.62 4.60 1.50 3.98 0.97 0.96 l. 70 1. 31 400 2.31 o. 7l 5.00 1.67 4.24 1.00 1.06 1.84 1.41 450 2.64 0.89 5.26 1.92 4. 77 1.13 1.34 2.04 1.61 500 3.30 1.69 6.71 2.50 6.10 1.62 1.92 2. 72 2.01 550 5.94 4.63 11.57 4.01 10.87 2.67 4.99 4.25 4.42 600 7.26 6.76 12.62 4.34 13.25 2.92 9.79 4.51 5.33 650 7.76 7.48 13.15 4.51 13.78 3.01 1. 52 4.59 5.53 700 8.00 7.83 13.41 4.59 14.05 3.13 11.90 4.76 5.63

900 8.25 8.19 13.68 4.68 14.58 3.24 12.29 4.85 5.83 1050 8. 25 8.19 13.68 4.68 14.58 3.24 12.29 4.85 5.83 10

8

3 6 ----4:

0 · - -ttl 4 0::

2

1-0 1 ·1 1·2 1·3 1-4 1. 5 1-6 1· 7 1. 8 1·9 2 .o Slope ratio

Fig. 6-3 Relation between the ratio A/ W and the slope . [ aftc:r Carthew,19S5J 148 peak was measured in em. These parameters and the wt. % of

Kaolinite calculated therefrom by using above empirical r e lationship are listed in Table 6.24.

On the basis of the results obtained and presented in this chapter, it can be concluded that the morphological obse rvations from SEM of few clay samples show the presence of crystallised and non-crystallised Kaolinite with varying forms such as 'flower' and 'speks'.

The XRD, IR and DTA results when viewed together give clear indication that the clay sample from Tak in Vengurla taluka show rich content of kaolinite, followed by clays from Malvan and Kudal talukas. In comparison clays from

Sawantwadi taluka show more percentage of Kaolinite than clays from Kankauli taluka which are poor in Kaolinite content with average of 28.18 percent. Ta ble 6. 2 4 The 'i ·Jantitative estimlltion of Kaolinite in c lays fro•n Sinjh•Jdurg District.

Taluka Locality Slope Average Width in trom peak area AN A/W r'ro•. Kaolinite Ratio em (\ol) peak ri'\ .6 . 1 percent cm 2 (A)

Sa\/antwadi Sawantwadi 1. 4 7 3.80 1. 30 2.92 7.30 32 . 00 Namale 1. 71 4.30 1. so 2.87 8. 10 28.35 Talawade 1. 46 s . 10 1. 30 3.92 7.20 43.56 Otavane 1. 62 7.70 1. 70 4.S3 7.80 46.46 ------Kankauli Janau li l. 29 2.50 1. 20 2.08 7.00 23.77 4arkul 1. 53 5. 00 1. 30 3.85 7.60 40 .53 Kankauli 1. 17 2 . 50 1. so 1. 6 7 6.60 20 . 24 ------

Mal van Kumbharmat 1. 69 8.40 1. 40 6.00 8 0 15 58 . 90

Kud a l Kasal 1. 38 5.60 1.10 S. 09 7 0 10 57.35 Pat 1. so 7 . 10 1. 40 5.07 7.50 54. 10 Mangaon l. 53 6.60 1. 80 3.67 7.60 38.63 ------Vengurla Tulas 1.46 6 . 00 1. 20 5 . 00 7.45 53.69 Ve ngurla 1. 24 -3. 20 1. 30 2 . 46 6.7 5 29.1& Mahpan 1. 71 7.20 1. 20 6 . 00 8.00 60.00 Ad eli 1. 70 3.40 0.90 3. 78 8. 00 37.80 Tak l. 2 2 16.30 2. 10 7.76 6 . 80 91.29