11
Chapter 2 : Geology and Soils
2.1 Introduction
Geology is the scientific study of the Earth, including its composition,
structure and physical properties. Groundwater resources of any magnitude have a
direct relationship to the geology and geomorphology because the nature and extent
of these aquifers are controlled by the regional and local geology. A clear
understanding of physiographical, structural and lithological characteristic features
of various geological units is important to access the qualitative and quantitative
distribution of groundwater in hard rock terrains. The hydrologic properties of the
aquifer depend on the nature of the rocks and soils that constitute them. Another
important parameter that is controlled by geology is the quality of groundwater that
is yielded by that aquifer. A basic understanding of the geology of the terrain
provides an insight in to the occurrence and quality of groundwater.
This chapter highlights the geological conditions of Karnataka in general; the
lithological characteristic features, structural alignment and soil study and their
characteristics in the study area in particular.
2.2 Geology of Karnataka
The Peninsular India is divided into five discrete crusts namely Bhandar,
Singhbum, Aravalli, EasternGhats and southern India.
The Archaen terrain of southern India records geological events that occurred
essentially during c. 3.4 to 0.5 Ga. It can be divided into two principal terrains based
on the grade of metamorphism as (1) Southern high‐grade granulite terrain and (2)
Northern low‐grade granite ‐ greenstone terrain. The boundary between these two
terrains appears to be a kind of transition which is superimposed across the
structural grain (Chadwick et al., 1992). The southern high‐grade terrain
encompasses large areas in Tamil Nadu, Kerala and part of Karnataka states and is
12
essentially composed of gneisses punctuated with rafts of supracrustal rocks. The
rocks of the terrain exhibit a polymetamorphic history, with the youngest event
recorded at c. 500 Ma, which, may be correlated with the Pan‐African orogeny
(Chacko et al., 1987). The northern low‐grade terrain is spread over major parts of
Karnataka and Goa and parts of Andhra Pradesh and is composed of several
supracrustal (greenstone) belts surrounded by gneisses and granitoids. The northern
low‐grade terrain has been referred to variously as Dharwar craton, Karnataka craton
and Dharwar nuclei (Pichamuthu and Srinivasan, 1984; Drury et al., 1984;
Radhakrishna and Naqvi, 1986; Rogers, 1986 and Mukhopadhyay, 1986). In the
present work, the name Dharwar craton will be used to describe the northern low‐
grade terrain.
2.3 Dharwar Craton
The Dharwar craton can be divided into the western and eastern blocks, the
dividing line being a steeply dipping mylonite zone interpreted by Chadwick et al.,
(1992) as a listric structure, and as a low angle thrust which becomes shallow at
depth as proposed by Kalia et al., (1979). The western Dharwar and the eastern
Dharwar craton are separated by younger granites. These cratons have a billion years
of early history of the earth shown in Fig. 2.1.
2.3.1 Western Dharwar
The western block contains several major supracrustal belts of the Dharwar
craton; most conspicuous among them are: Holenarasipur, Nuggihalli, Bababudan,
Shimoga‐North Kanara and Chitradurga‐Gadag belts. In the south, several minor
supracrustal belts are also found admist gneisses. The supracrustal lithologies of the
western block can be classified into the older Sargur group and the younger Dharwar
supergroup (Swaminath and Ramakrishan, 1981).
The decisive factor in this classification is that the supracrustal rocks of
Dharwar supergroup lay unconformably over c. 3.0 Ga Peninsular gneiss basement,
13
Figure 2.1: Geological map of Karnataka (After Radhakrishna et al., 1991)
14
whereas the Sargur group of rocks are intruded by c. 3.0 Ga Peninsular gneiss and,
hence, are older than the gneisses. Several researchers adopt this broad
classification, although Naha et al., (1993) questioned the validity of attaching
stratigraphic significance to the Peninsular gneiss, which is a polyphase gneiss
evolved over a long span of time between c. 3.4 and 2.5 Ga. The available
radiometric dates of supracrustal rocks and gneisses appear to be consistent with
this broad two‐fold division, wherein, the Sargur group of rocks have been deposited
during c. 3130‐2960 Ma (Nutman et al., 1992) and supracrustal rocks of Dharwar
supergroup accumulated during c. 2900‐2600 Ma (Taylor et al., 1984). The polyphase
migmatitic gneisses yielded radiometric ages ranging from 3.4‐2.5 Ga, but large areas
recorded ages of c.3.0 Ga. The Supracrustal rocks and Peninsular gneisses are further
intruded by K‐rich granites which are c. 2.5 Ga old (Taylor et al., 1984 and Bhaskar
Rao et al., 1992).
The younger Dharwar supergroup has been subdivided into (a) the Lower
Bababudan group and (b) the Upper Chitradurga group, based on the presence of a
persistent polymict conglomerate horizon, marking the unconformity between these
two groups. The general stratigraphic succession of the lithologies of the western
block of the Dharwar craton is summarized below:
c 2500 Ma Syn‐to post‐kinematic granites (Closepet granites) Dharwar supergroup (Bababudan
group and Chitradurga group) c 2900 Ma – 2600 Ma
Unconformity
c 3000 Ma Peninsular gneiss. Sargur group
c 3130 Ma ‐ 2960 Ma Unconformity
c 3400 Ma‐ 3200 Ma Early sialic basement (inferred)
Table 2.1: Stratigraphy succession of the lithologies of the western block of the Dharwar craton
15
2.3.2 Eastern block
The supracrustal belts of the eastern block of the Dharwar craton, which are
surrounded by gneisses and granites, are smaller in size than those of the western
block. The prominent greenstone belts of the eastern block include Kolar, Sandur and
Hutti. These belts contain abundant volcanic rocks and minor amounts of
sedimentary rocks. The volcanic rocks belong essentially to ultramafic‐mafic suite
with minor felsic end members. The sedimentary rocks are essentially made up of
quartzites, polymict conglomerate, carbonates, BIF and Mg‐rich pelitic rocks and
phyllites. The supracrustal rocks are intruded by c.2.5 Ga old syn‐to late/post‐
tectonic granites. The stratigraphic status of the supracrustal rocks of the schist belts
has not been worked out in detail. However, metabasalts from Kolar schist belt
yielded a Sm‐Nd age of c.2.7 Ga, indicating that they are contemporaneous with the
Chitradurga group of the western block (Rajamani et al., 1981 and 1985).
Majority of the granitoids and gneisses of eastern block yielded an age
ranging from c. 2.6 to 2.5 Ga (Nutman et al., 1996). According to Krogstad et al.,
(1991), the granites near the Kolar schist belt were possibly generated from a mantle
source with insignificant crustal involvement. According to Martin et al., (1993), the
post‐kinematic granites have been generated by melting of metasomatized mantle
source. Unlike the western block, the age and nature of basement for the
supracrustal rocks of eastern block is poorly constrained. As mentioned earlier, the
exposed gneissic crust of the western block is largely c. 3.0 Ga old, whereas similar
gneisses are rarely found in the eastern block. On the other hand, the eastern block
is extensively invaded by syn‐to post‐kinematic c.2.6 to 2.5 Ga old granitoids.
The western and eastern cratons are further classified as 1) Ancient
Supracrutal, 2) Older and younger Gneissic complex, 3) Auriferous Schist Belt, 4)
Larger Schist Belt, 5) Younger Granites, 6) Granulites, 7)Younger Intrusive‐Dyke
Swaps, 8) Great Eparchaen Intervals, 9) Proterozoic Sedimentation , 10) Deccan
Traps, and 11) Laterite. Brief descriptions of the above groups are explained as
bellow:
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2.3.2.1 Ancient Supracrustal (Sargur Type)
The Sargur group of rocks occurs as independent enclaves, thin slivers and
tectonic slices within the peninsular gneisses confined mainly to the southern fringes
of the lower‐grade terrain of Dharwar craton and occur within the transition zone
between northern lower‐ and southern higher‐grade terrain. The basement for these
rocks are not identified anywhere but, a sialic basement has been inferred based on
detrital zircon grains present in the quartzite of Sargur group (Chadwick et al., 1986
and Nutman et al., 1992), although there are suggestions for the presence of ANT
(Lunar‐type) basement for these rocks (Naqvi, 1978).
Important linear belts of Sargur group of rocks are well exposed at Sargur,
southern part of Holenarsipur, Nuggihalli, Krishnarajpet, Sasivala, Ghattihosahalli and
Belavadi.
The supracurstal rocks of the Sargur group are composed of diversified
igneous and sedimentary lithologies. They include ultramafic‐mafic volcanic rocks,
pelites, quartzites, impure carbonates, iron formations and ultramafic‐mafic intrusive
bodies (Swaminath and Ramakrishan, 1981).
The schist belts consisting of Sargur group of rocks, being situated in the
transition zone between northern lower‐grade and southern higher‐grade terrain,
have also been subjected to upper amphibolite to granulite grade metamorphism c.
2.5 Ga ago (Buhl et al., 1983 and Sirkantappa et al., 1985). Volcanic rocks of Sargur
group are composed of komatiite‐tholeiite suite, in which the komatiite
predominates over the tholeiites. Drury (1983) opined that the parent melts for the
ultramafic‐mafic volcanic rocks were generated through melting of mantle diapir at a
depth of about 70 km in a back‐arc environment. However, Rajamani (1990)
considered that the ultramafic‐mafic volcanic rocks of the Sargur group are not
genetically related either to common parent magma or to a common source.
According to him, the komatiitic magma originated from deeper mantle source at
depths of about 100 km and tholeiitic magma formed at depths <50 km.
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2.3.2.2 Older and Younger Gneissic Complex
The gneisses lying within Karnataka is nucleus form, occupied about 35% of
the area and exhibited an extreme diversity of composition and are divided into
three groups (Radhakrishna and Naqvi, 1986) which are as follow:
A complex of banded gneisses showing multiple deformations.
A suite of much less deformed, nearly massive gneisses of broadly similar
composition but which apparently developed subsequently to the deformation that
effected the earlier banded gneisses and
Late tectonic potassium (K) rich granitic gneisses.
Three major events at 3400‐3300, 3100‐3000 and 2600‐2500 m.y, are
suggested for peninsular gneisses based on geocronological data
(Venkatasubramanian; 1974; Beckinsale et al; 1980, 1982, Raja gopalan et al.; 1980
and Taylor et al.; 1984). These are also designated as older gneisses complex and act
as basement for an extensive belt of schists. A younger group of gneissic complex is
found in eastern part of Karnataka having an age of 2700 to 2000 m.y, mostly of
granodioritic and granitic in composition.
2.3.2.3 Auriferous Schist Belts (Kolar type)
Next to the older and younger gneissic complex lie a series of basic igneous
rocks of basaltic composition together associated with intrusive. They are mainly
igneous in character with a subordinate sedimentary intercalation. The most
characteristic feature of these rocks is their auriferous nature. They are well
developed in the eastern part of the Karnataka state. A typical representative of
these eastern belts is the Kolar schist belt. The name, ‘Auriferous schist belt’ are the
belts, which are largely volcanic and gold bearing.
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2.3.2.4 Larger schist belts (Dharwar type)
These are the prominent schistose rocks of Karnataka named ‘Dharwar schist
belt’ with a super group status. They belong to the late Achaean and their age group
dates back to 2900‐2600 m.y. The two main divisions in this super group are
recognized. The older group is mainly igneous in character. Overlying this is a more
extensive group of schistose, largely sedimentary in nature, composed of
conglomerates, quartzites, limestone, greywacke and associated manganiferous and
ferruginous cherts which are named as ‘Chitradurga group’. The ‘Rani Bennur group’
is the youngest series of sediments, mostly greywacke in composition and
intercalated with cherty iron formation. These are classified as topmost formation
within the Chitradurga group.
2.3.2.5 Younger (Closepet) granite
Most prominent of the younger granite is the linear belt of Clospet granite
having a length of nearly 500 kilometers. The trend of this granite is roughly North‐
South and parallel to the structural grains of the host rock. The geocronological data
suggest that the two major events experienced in the emplacement of Closepet
grantite at 2400‐2600 m.y and 2000 m.y (IIkaramuddin, and Stueber, 1976 and
Jayaram et al., 1983). Chitradurga and Banawara groups belong to the same age.
2.3.2.6 Granulites
Southern part of the Dharwar craton is granulite terrain with extensive
development of charnokite and pyroxene granulite. Geochronological data indicates
an age of 2500‐2700 m.y. (Ramiengar et al., 1978). These are believed to be
originated because of high‐grade metamorphism and metsomatic alternation of the
older gneisses.
2.3.2.7 Younger intrusivesdykes swamps
The close of Achaean is marked by a period of dyke formation with both NS
and EW trending dykes traversing rocks of earlier ages. These are ultramafic of
19
doleritic composition and may belong to different ages. The majority of the dykes are
younger than 2400 m.y. Besides ultramafic dolerite, a number of alkaline dyke
intrusives have been seen especially from southern parts of Karnataka, (Bangalore
and Mysore) which are younger and in all probability unrelated to the dolerite dykes
but may be connected with younger granitic activity.
2.3.2.8 Great Eparchaean interval
A long period of stability of more than 1000 m.y duration exceeds the
Archaean, during which the earlier rocks were exposed to the action of winds and
water. This period is called as Eparchaean unconformity.
2.3.2.9 Deccan traps
The next major event is the burst of volcanic activity at the end of the
cretaceous‐dawn of tertiary era. This is represented by a horizontal sheets of lava
piling one upon the other over a thickness of nearly 2km and extending over a area
of 5,00,000 km2. The burst of volcanic activity was sudden and continuous with
hardly any interval between the flows. The volcanic episode was short not exceeding
more than a million years. Northern Karnataka particularly the districts of Belgaum,
Bidar, Bijapur and Gulburga are covered by these Deccan traps. The fossils
embedded in these suggest a tertiary age (Radhakrishna and Vaidyanatha, 1997)
The western margin close to the coast was affected by large‐ scale dyke
intrusion. The dyke assigned an age around 65 m.y, connects them with the Deccan
volcanic activity.
2.3.2.10 Laterite
Over the Deccan trap capping of laterite is found which probably started
forming at the cessation of Deccan volcanic activity in early tertiary and are
continuing to form even today. The narrow coastal belt between the coast line and
the precipitous edge of the western ghat in a plain of marine denudation and is
covered by the extensive capping of detrital and residual laterite.
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2.4 Geology of the study area
The geological map of the study area (Fig. 2.2) has been prepared using the
existing geological map of Geological Survey of India (GSI, 2007) and updated by
using satellite imageries of LISS III plus merged PAN data. The major rock types of the
study area are represented by the basement gneisses of the “Peninsular gneissic
complex”. Amphibolites belonging to the Sargur Group of older metamorphic occur
as linear enclaves within the peninsular gneiss. A number of younger ultramafic
dolerite dykes and pegmatite veins intrude into these lithologies.
The following geological table gives a general succession of the rock exposed
in the study area:
Rock Type
Quartz Vein
Pegmatite
Dolerite Dykes
Charnokites
Peninsular gneiss
amphibolites
Table 2.2: General succession of the rocks of the study area
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Figure 2.2: Geology map of the study area
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2.4.1 Amphibolites
The older metamorphics of Sargur Group represented by amphibolites
occurring as lensoidal /linear enclaves within the peninsular gneiss are exposed
mostly in the central western, eastern and southern western part of the study area.
Amphibolites are fine to medium grained, dark green, well foliated and consist of
hornblende, plagioclase, epidote and minor amounts of biotite and quartz.
2.4.2 Peninsular gneisses
Peninsular gneiss is the predominant rock of the study area (Plate 2.1), which
runs from north to south; east to west direction more or less gently undulating plains
with high grounds seldom gives rise to small hillocks and mounds. The peninsular
gneiss is represented by migmatite with varying composition from granodiorite to
tonalite and is banded, grey, coarse grained and consists quartz, plagioclase,
hornblende at places and minor amount of biotite. At a number of dolerite dykes,
laces of pegmatites and quartz veins are seen cutting across gneisses. In the study
area, Peninsular gneisses mostly form pediplains of shallow weathered and less
exposed and only in the south‐western part of the study area the peninsular gneiss
occurred as highly weathered ground level outcrops.
2.4.3 Charnockite Suite
The name charnockite is applied to a series of rocks, which are characterized
by the presence of rhombic pyroxene, chiefly hypersthenes that formed by them as a
special petrographical province in India. Charnockite suite is represented by
charnockite and pyroxene granulite. Charnockite occurs as mega linear and small
lensoidal bodies within Peninsular Gneiss, exposed mainly in the central part close to
Hunsur, and also in parts of the south south‐western part of the study area. It is
medium to coarse grained, dark grey, greasy looking and consists of hypersthene,
feldspar, quartz and magnetite at places. Thin lenses of pyroxene granulite occur
within peninsular gneiss, exposed in central and north‐eastern part of the area.
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Plate 2.1: Banded Gneisses , Madapura village
2.4.4 Dolerite Dykes
Basic intrusive of the study area represented by dolerite dykes (Plate 2.2).
These dykes are seen traversing the peninsular gneiss concordantly as well as
discordantly which trend mostly from N‐S and NW‐SE directions. These dykes appear
in the field as boulders strewn ridges running for considerable distances. The major
dolerite dyke of the study area is about 20‐30 m wide and 15 km long running from
the NW‐SE direction. Many a times these dykes are irregular along length but
maintain the same general trend and the continuity. Dolerite dykes could be
identified by their dark colour on the satellite imagery. They are fine to medium
grained, dark green and consist of mainly pyroxene and laths plagioclase. These
dolerite dykes act as barriers at places for the movement of groundwater below the
surface. The weathering effects in these rocks are less compare to the host rocks
such as gneisses.
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Plate 2.2: Dolerite Dykes
2.4.5 Acid Intrusive:
Acid intrusive are represented by pegmatite and quartz veins.
2.4.6 Pegmatite Veins
Pegmatite veins (Plate 2.3) occurring as small bands within peninsular gneiss
complex are trending NW‐SE and S‐W.
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Plate 2.3: Pegmatite Veins with Ultramafic bodies seen in Omkareshwar betta
2.4.7 Quratz Veins
These intrusives are found mainly in the south‐eastern part of the study area.
They are fine grained light coloured and trending towards NW‐SE, and W‐E direction.
2.5 Structures
A wide variety of structures are seen in the area in the form of folds, faults,
joints and foliation. Except Northern part the, remaining portion of the study area is
affected by the intrusion activities which have resulted in the form of deformations
(GSI, 2007).
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2.5.1 Lineaments
Mapping of lineaments is very useful, especially in hard rock terrain where
occurrence and movement of groundwater is mostly confined to these linear
features. A careful study of lineaments in conjugation with the drainage, topographic
characteristic can lead to the selection of suitable well sites. The following map
shows the lineament of the study area (Fig. 2.3).
Figure 2.3: Structural map of the study area
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2.6 Soils
Soils are highly porous and are the product of weathering of rocks
(Shivaprasad et al., 1999). Varied lithology produces different types of soils. The
amount of groundwater recharge, storage, discharge, as well as the extent of
groundwater contaminations, all depend on the soil properties. Soil inventory study
was conducted using digital analysis of LANDSAT data along with conventional
methods in the Central Spain by Labarndero and Palou (1978). These workers have
classified the soils into nine bare soil classes and five classes of soil covered with
vegetation under Alfisols, Entisols and Inceptisols. The visual interpretation
technique makes it possible to recognize the soil and map the soil from the spectrum
of soil properties like texture, color, moisture, structure, etc., and soil forming
conditions consisting of land form, drainage, parent material, vegetation,
hydrogeology, etc., reflected on the imagery (Lin Pie, 1981). In India, Remote sensing
and GIS techniques have been used by several workers (Jayaraman et al., 1990;
Prabhakar, et al., 1996 and Prasad et al., 2001) for mapping of soils in different parts
of country.
2.6.1 Mapping and classification of soils in the study area
The soils identified in the study area have been classified based on United
States Department of Agriculture (USDA, 1975) taxonomic scheme. According to this
scheme, 3 orders have been identified viz., Alfisols, Inceptosols and Ultisols
followed by 4 sub‐orders viz., Ustalfs ,Tropepts, Humults, and Ustults and 5 great
groups viz., Paleustalfs, Paleuhumults, Ustropepts, Haplohumults and Haplustalfs
and 7 sub‐groups viz., Lithic Ustorthents, Typic Ustropepts, Kandic Paleustalfs, Ustic
Haplohumults, Kanhaplic Haplustalfs, Ustic Palehumults and Rhodic Paleustalfs
(Table 2.3).
28
Order Sub_Order Great‐Group Sub_GroupAlfisols Ustalfs Paleustalfs Kandic Paleustalfs
Rhodic PaleustalfsUltisols Humults Paleuhumults Ustic PalehumultsInceptisol Tropepts Ustropepts Lithic Ustorthents
Typic UstropeptsUltisols Humults Haplohumults Ustic Haplohumults
Ustults Haplustalfs Kanhaplic Table 2.3: Soil classification of Western Part of Hunsur Taluk according to USDA (1975)
These soil classes have been mapped from merged satellite data of IRS 1 C
and 1 D of both LISS III and PAN and topographic maps were used as reference. The
soil map generated based on sub‐group for the study area is shown in (Fig. 2.4). The
brief description of different soil sub‐classes are given below:
Sub‐Group Family Texture Soil ‐ Taxonomy
Kandic Paleustalfs Clay
Fine, Kaolinitic, Rhodic Paleustalfs. Fine Kaolinitic, Rhodic Kandiustalfs
Rhodic Paleustalfs
Clay Skeletal
Clayey‐skeletal mixed Rhodic Paleustalfs. Clayey‐skeletal, mixed, Typic Rhodustalfs
Kanhalpic Haplustalfs
Clay
Clayey‐Kaolinitic, Kanhaplic Haplustults. Clayey‐skeletal, mixed, Kanhaplic Rhodustalfs.
Lithic Ustorthents
Clay
Loamy‐skeletal, mixed, Lithic Ustortents. Clayey‐skeletal, mixed, Lithic Ustropepts
Typic Ustropepts Clay
Fine, mixed Typic Ustropepts. Fine, mixed, Typic Ustifluvents
Ustic Haplohumults
Clay Skeletal
Clayey‐skeletal, Kaolinitic, Ustic Haplohumults. Clayey‐skeletal, Kaolinitic, Ustic Kanhaplohumults.
Ustic Palehumults
Clay
Clayey, Kaolinitic, Ustic Palehumults.
Loamy‐skeletal, mixed, Ustic
Kandihumults.
Table 2.4: Soil‐Taxonomy of Western Part of Hunsur Taluk according to USDA, 1975
29
Figure 2.4: Soil map of the study area
2.6.1.1 Lithis Ustorthents:
This sub‐class consist of very shallow, excessively drained, gravelly loamy soils
on ridges with severe erosion; associated with shallow somewhat excessively
30
drained. Gravelly clay soils with very low Available Water Capacity (AWC),
moderately eroded.
2.6.1.2 Typic Ustropepts
This sub‐class consist of deep, well drained, yellowish red, sandy clayey soils
on undulating interfluves, with moderate erosion; associated with deep, well drained
clayey soils (Plate 2.4).
2.6.1.3 Kandic Paleustalfs
This sub‐class consists of deep, somewhat excessively drained, gravelly clay
soils on gently sloping interfluves, with moderate erosion; associated with deep,
somewhat excessively drained, clayey soils.
2.6.1.4 Ustic Haplohumults
This subclass consists of very deep, well drained, gravelly clay soils with low
AWC on low hill ranges, with moderate erosion; associated with moderately deep,
somewhat excessively drained, gravelly clay soils.
2.6.1.5 Kanhaplic Haplustalfs
This Sub‐class consists of deep, well drained, clayey soils on undulating
uplands, with moderate erosion; associated with deep, well drained, gravelly clay
soils, with low AWC.
2.6.1.6 Ustic Palehumults
This sub‐class consist of very deep, well drained, clayey soils with medium
AWC on isolated hills, with moderate erosion; associated with deep, somewhat
excessively drained, gravelly loam soils with stoniness, severely eroded.
31
2.6.1.7 Rhodic Paleustalfs
This sub‐class consists of moderately deep, well drained, clayey soils on
undulating interfluves, with moderate erosion; associated with moderately deep,
well drained, fine gravelly loamy soils, moderately eroded and has a high AWC.
Plate 2.4: Field photograph showing sub‐group Typic Ustropepts type of soils
32
Plate 2.5: Field photograph showing sub‐group Rhodic Paleustalfs type of soils
2.7 Significance of Studying the geology and Soli of the study area
From hydrogeolical point of view studying the rock and soil types of the study
area becomes important. As discussed earlier the bed rock of the study area is
composed of hard rock terrain of peninsular gneisses and are devoid of primary
porosity. Thus the ground water availability is dependent upon the development of
secondary porosity caused by the weathering and fracturing of the rock matrix.
Hence studying the rock type and also its structure helps to identify the zones of
recharge of the groundwater. Water‐holding capacities of soils which in turn increase
the infiltration rate of water in to subsurface depend on the soil texture and its
organic matter. Soils with higher percentage of silt and clay have a higher water
holding capacity. It is understood that the soil texture with its available water capacity
characteristic plays an important role in infiltration of water in to subsurface and studying
the different soil texture is important in hyrdogeological studies.