GEOLOGY OF THE AREA - Shodhgangashodhganga.inflibnet.ac.in/bitstream/10603/16970/10/11_chapter 3.pdf · Geology of the Area With digital image processing, ... To delineate lineaments

3.1 Introduction

CHAPTER-III

GEOLOGY OF THE AREA

(A) Role of geological studies in the Environmental and Resource evaluation:

Geological factors greatly influence man and his activities. The discipline of environmental

geology embraces the whole gamut of human use of the earth. A clear comprehension of

the dynamics and mechanisms of the various earth processes that give rise to mineral

deposits, control movement and storage of surface and ground waters, shape terrain

morphology and landscapes and lead to soil type formation is an essential prerequisite in

understanding, preserving and restoring natural environment. A geologist is well equipped

to evaluate the capability of the earth for providing water, minerals and other resources, to

select appropriate sites for construction of engineering structures and for disposal of water

and pollutants and to identifY lands for supporting agriculture, forestry, industries and

urban centres.

The major areas in which the role of earth sciences are of vital importance include terrain

evaluation, landuse planning, hydrogeology, water management, earth resources

conservation and management, geological hazards, engineering structures, waste disposal,

pollution control and alternate sources of energy (V aldiya, 1987).

(B) GeologicaV lithological maps incorporate a large and varied geological data from field

observations and field and laboratory measurements, but they are in part subjective because

field measurements are always limited by rock exposure, accessibility, man power

resources and the spectral range under which a human being can see.

But with remotely sensed satellite data, having manifestation of the wide spectral and

emittance characteristics of the surface material, synoptic view and repetivity. it is possible

to obtain certain structural and lithologic information more efficiently than those which can

be achieved on the ground. A major hurdle in geological remote sensing is that invariably

the surface outcrop is covered by the vegetation or weathering products, so that the various

Geology of the Area

---------------------------------------------------------------

strands of evidence have to be taken to infer the lithology or structure from remotely

sensed data (Barret and Curtis, 1982).

For better delineation of lithological and structural features, remotely sensed data must be

used along with the existing field geological map (Goetz and Rowan. 1981) and the result

of geophysical and geochemical surveys through digital image processing and geographical

information system (Abrams et.al., 1983; Lyberis et.al., 1990).

One of the basic information that remotely sensed data can provide for the exploration of

the groundwater, mineral and hydrocarbon, and location of power plants and dam sites and

earthquake studies is lineament pattern of the area (Rowan. 1975). These are the alignment

of regional morphological features and zonal features that in many areas are the surface

expression of fracture or fault zones, ranging from few kilometre to hundred of kilometres

(Goetz and Rowan. 1981; Drury, 1986; Sabins, 1987).

In a hard rock terrain, lineaments interpreted from satellite imagery represent faults, joints

and dykes of several ages. Such fissured rocks are more and more susceptible to deep

weathering and are therefore ideal locations for bore well drilling (Greenbaum, 1992).

In mineral exploration, space borne data has been used in three ways (Amos and

Greenbaum, 1989; Rowan et.al., 1977; Rowan and Wetlaufer, 1981; Sabin, 1987):

1. Delineation of regional lineament, along which groups of mining zones may occur

l. Delineation oflocal fracture pattern that may control individual ore deposits

3. Identifying features directly related to mineralization, such as alteration zones,

alteration haloes, gossan and specific host rock association.

The hydrothermally altered country rocks contain distinctive assemblage of secondary or

alteration minerals that replace the original constituents. In regions where bedrock is

exposed, multispectral remote sensing have been found useful for recognising altered rock

because their reflectance spectra differ from those of country rocks (Rowan et.al., 1977).

Geology of the Area

With digital image processing, it is possible to manipulate and combine a large number of

spectral bands and images or other types of data sets. Digital image processing techniques

applied to geologic problems include contrast enhancement and spatial filtering to enhance

morphological or structural information, arithmetic operations such as ratio of spectral

bands to enhance spectral reflectance d.iffereoces and suppress systematic effects such as

topography. Statistical analysis is used to reduce dimensionality in data set containing many

spectral bands or other variables (Abram et.al., 1983; Amos and Gt-eenbaum, 1989).

3.2 OBJECTIVES:

The geology of the area was studied with the following main objectives:

1. To delineate various litho-units and to locate the mineral resource of the area

n. To delineate lineaments through visual interpretation of satellite image and digitally

processed images.

m. To find out the lineament frequency density and lineament intersection density of the

area

N. To recognise litho-units and structures which are potential from groundwater point of

view

v. To estasblish the interrelationship between soil erosion and various litho-units

VI. To estasblish interrelationship between soil physiography, land capability, landuse and

various litho-units

3.3 METHODOLOGY

I. Existing geological maps and literature were collected.

D. Visual interpretation of hard copy of IRS-ffi LISS- ll satellite image was done in

conjunction with SOl toposheet. As area is covered with vegetation or weathered

mantle, digital image processing was done to enhance structures and litho-boundary.

Ill. Tentative geological map was prepared using visuallY interpreted maps, digitally

enhanced products and existing geological maps. Table 3.1 show the image

characteristics of various lithounits. The digital image processing techniques and their

significant results have been given in Table 3.2.

26

Table-3.1 Image Characteristics for Different Litho-units

Utho-unlts Tone/ Colour on FCC 432 Drainage Pattern Texture Structure Land use Morphogentlc Trend line chancterlstlcs

1) Dhandraul Reddish brown (Vegetation covered) to Coarse, Sub-paraUel Coarse Flat top surface Forest dense, Fanning plateau litho-contact Quartzite reddish yellow (agricultural land) agriculture sharp, trend line

visible l) Scarp sandstone ButT creamy Parallel, medium Medium Steep slope Degraded barren Scarp face 3) Bijaigarh shale Creamy Parallel to sub-parallel medium Forest, agriculture Valley portion Trend line not

sharp 4) Upper Quartzite Greenish brown to reddish yellow Coarse, sub-parallel Medium to Trendline Mainly forest

coarse visible 5) Silicified shale Greenish brown to reddish yellow, Coarse, sub-parallel Fine _,,_ Forest

reddish 6) Lower Quartzite Brownish red to cream Medium, sub-parallel Fine to medium 7) Rohtas, Reddish brown to greenish brown at Medium, sub-parallel Fine to medium _,,_ Forest, agriculture

limestone, Shale forested part, reddish to yellowish red at agricultural land

8) Glauconitic beds Reddish brown to greenish brown at Medium, sub-parallel Fine to medium _,,_ Mostly agriculture, forested part reddish to yellowish red at forest agricultural land

9) Fawn 1st Reddish brown to greenish brown at Medium, sub-parallel Fine to medium _,,_ Mostly agriculture, forested part, reddish to yellowish red forest at agricultural land

10) Olive shale Reddish to chocolate brown Medium sub-parallel Fine to medium "

agriculture, forest 11) Porcellanite Brownish grey (drg. forest), red Medium, parallel Medium to Dissected Agriculture, Denudational hill

(agriculture) coarse surface degraded forest 12) Kajarhat Greyish brown to yellowish grey, white Parallel to sub-parallel Medium to Dissected Mining, Linear structural

limestone at mining cream to red at agricultural coarse agriculture, barren sheet with land trendline

13) Arangi shale Brownish grey Coarse, parallel Fine Linear Agriculture, dry Side slope of linear forest structural hill

14) Patherwa Coarse, parallel Fine Linear Degraded forest Side slope of linear formation structural hiU

15) Lotan form Reddish brown to brown and creamy at Trellis Medium to Ridge, valley Forest Ridge and valley degraded forest coarse topography of the

dissected hill

Geology of the A. rea

IV. Field work was carried out at selected sites to check and modify the geological and

lineament maps and to collect other structural information.

V. After field check final geological (Plate 3.la) and lineament map (Plate 3.1b) were

prepared.

VI. The direction, length and number of lineaments were measured and rose diagrams of

frequency and length were prepared to depict major stress direction.

Vll. Lineament map was divided into one square km grids and the number of lineaments

and number of lineament intersections within each grid were counted at the central

point of each grid separately. These were contoured using triangulation method, and

the lineament density and lineament intersection density maps were prepared.

Table- 3.2

DIGITALLY ENHANCED IMAGES AND FEATURES HIGHLIGHTED

Combination Feature highlighted

FCC432 Highlight broad litho-units

Band 4 (Laplacian Highlight litho-boundary, landform and

filter) lineament

PC2 Highlights all lineaments, litho contacts very

prominently, folding and faulting

Hybrid FCC, PCI, Highlights structure and litho contact In

PC2, PC3 Upper Vindhyan and Mahakoshal,

lineaments

Hybrid: 'FCC, 4 Differentiate Porcellanite and limestone

(LF), 3 F), 2 (Kajarahat) and litho contact

3.4 GEOLOGY OF THE AREA

3.4.1 Regional geological set up: The area is comprised of two distinct groups of

geological formations:

I. The Pre-Vindhyan meta-sediments and volcano-sedimentary sequence of early

Proterozoic (Plumb and James, 1986), known as Mahakoshal group of rocks (Rogers,

28

Plate 3.la : Geological Map

LINEAMENT MAP OF DAtA · RENUKUT AREA

80NBHADRA OIST. UP, INDIA

Plate 3.1b : Lineament Map

Geology of the Area

I. 1986; Dutta, 1986) consisting of phyllite, quartzites, schists and marble, banded iron

formation etc. (Roy and Bandopadhyay, 1990) occupying a large part of the area.

IT. The Semri and Kaimur group of the Vmdhyan super group (Auden, 1933),

conspicuously exposed in the northern part of the area.

The Semri group of rocks (Lower Vmdhyans) consisting of limestones, shales, glauconite

beds. porcellanite, silicified rocks and basal conglomerates, sandstone and shale (now the

Patherwa formation and Arangi shale; Prakash, 1967) are exposed along the Son river on

either side, while the Kaimur group of rocks (Upper Vmdhyans) consisting mainly of

qUartzite, sandstone and shale form conspicuous by high relief in the extreme north of the

area (Auden, 1933).The sequence litho-stratigraphy of the study area is given in the Table

3.3.

3.S DISTRIBUTION AND CHARACTERISTICS OF DIFFERENT LITHO-UNITS:

3.5.1 Mahakoshal group

3.5.1.1 Panoi formation: The rocks ofParsoi formation are exposed north ofBelguri nala

and south of Dala and Obra. These are comprised of chlorite-phyllite and schist with

interbands of meta-semipelite, meta-sub-greywacke and meta-volcanics. Locally bands of

marble and quartzite are seen in the formation towards the base.

The rocks form uneven topography, locally with prominent strike ridge having hogback

features formed due to differential weathering of quartzite and schist bands. The schist

bands occupy valley portions in between the quartzite ridges. Drainage are coarse and

forms joint controlled trellis pattern. On satellite image (FCC 432), these are reddish brown

to brown when forested and creamy and reddish when covered by degraded forest and

agricultural land respectively. These are distinguishable from Vindhyan group of rocks by

its strike ridge trend and with Lotan formation by its more dissected and erosion prone

nature.

10

Table-3.3

LITHOSTRATIGRAPIDC SEQUENCE IN PART OF SON VALLEY AREA

(after Auden, 1933; Prakash, 1967; Iqbaluddin & Moghni. 1980; Dutta, 1986)

Groups Formation

Upper Upper Kaimur Group Dbandtaul Quartzite

Scarp Sandstone

Lower Kaimur Group Bijaigarb Shales

Vmdbyan Upper Quartzite

Supergroup Silicified Shales

Lower Quartzite

Lower Semri Group Rohtas Umestone & Shale Formation

Khenjua formation

Glauconitic beds

Fawn Limestone

Olive Shales

Porcellanite Formations

Kajarahat Limestone

Arangi Shales

Patherwa formation

Lotan formation*

Mabakosbal Parsoi formation 0

........ • Phyllite. meta-subgraywacke, meta-protoquartzite. marble and quartztte

e Sdsist. phyllite. quartzite. metasubgn:ywacke. mcta-protoquartzite

Geology of 1M Area

The phyllite and schists of Parsoi formation •e green, greenish grey and olive green in

colour. The rocks are fine to medium grained comprising quartz, chlorite and sericite. The

sheet minerals show lepidob1astic structure defined by preferred orientation of their

pinnacoidal faces parallel to the regional foliation. Locally, the phyllites are very fine

grained and porphyroblastic minerals are not well developed to make their identification

possible by unaided eyes.

Outcrops of marble were seen at Obra and Nmgha. These ocaJr as interstratified bands

with a high degree of lenticularity. In Obra, near the western abutment of the railway

bridge, marble is seen south ofKajarahat limestone outcrop. It is white, coarsely, crystalline

dolomitic marble.

The marble band in the Ningha shows cement grey colour on the weathered surface but on

the fresh surface as seen in the quany &ce, it is milky white. It is coarsely crystalline

comprising of predominantly calcite and is free from impurities.

These are tightly folded with E-W trend and dipping steeply(~ 70°) due north or south,

forming linear synclinal ridge and aotidinal valley topography. These are well jointed. The

strike trend and joint pattern give rise to characteristics trellis drainage pattern.

3.5.1.2 Lotan formation: These are exposed south ofBelguri nata in the study area. These

rocks are relatively coarser and schistose than the underlying phyllitic sequence of Parsoi

formation. Frequency of ocaJ.I'J"eDCe of meta-sub-greywackelmeta-protoquartzite/lithic

arenite is more in this formation, south of Jogidih village than in the Parsoi formation.

These rocks also form ridge and valley topography, but having higher relief than in the

Lotan formation. Softer rocks like scbists occupy mostly the valleys and side slopes while

the resistant quartzites form ridges.

On satellite image, they show cheny brown to brown tone on forest covered area, but

creamy to reddish on agricultural laud. These are less dissected than the Lotan formation.

Though there is no distinct image dlaracteristic to demarcate its boundary with Lotan

32

Geology of the Area

formation, but the prominent E-W running lineament along the Belguri nala, fonns the litho

contact between the two.

These are interstratified sequence of schist, meta-protoquartzite and meta-sub-greywacke.

The schist is dark green, medium to fine grained comprising predominantly of chlorite and

quartz with biotite and sericite OCCUlTing as common constituents. The schist around

Renukoot near the contact with migmatite shows higher grade of metamorphism manifested

by development of quartz muscovite schist. The sheet minerals show lepidoblastic structure

defining the first schistosity in these rocks.

Meta-sub-greywacke and meta-protoquartzite bands are seen interbedded with schist and

phyllite. These bands megascopically, at outcrop level can be distinguished from phyllite

and schist by their coarser texture and quartzose composition. The rocks are dusky to

subdued green in colour, medium to coarse grained comprising quartz, sericite, chlorite

and a little biotite.

The quartzite is greyish in colour, medium to coarse grained and at places sericitic. The

development of foliation is conspicuous, manifested by slight elongation of quartz grains

and preferred arrangement of sericite.

These are also tightly folded with E-W trend and dipping steeply (~ 70° ) due north or

south, forming linear synclinal ridge and anticlinal valley topography.

3.5.2 VINDHY AN SUPERGROUP

3.5.2.1 Pathenva formation: This is named after the nata of this name that occurs to the

south-west ofHardi village where a representative section is well exposed (Prakash, 1967).

The basal contact of this formation is unconformable with the basement rocks (Mahakoshal

Group) and towards the top this formation passes sharply into shales.

These are exposed as a narrow linear structural hill south of Data cement factory aligned in

East-West direction upto Hardi. The absence of any wide outcrop of this formation in the

33

Geologyofthe Area

area is due to faulting (Prakash. 1967). On satellite image it can be easily identified due to

its brownish grey tone with fine texture and conspicuous linear alignment.

These arenaceous rocks are usually formed of a sequence of unsorted pebble beds, which

are overlain by grits and graded pebble beds with multiple, often tangential, cross­

laminations. The parallel or cross-laminations are usually made up of sbaly laminae which

are often limonitic or hematitic. Overlying there are lenticular dirty sandstones, which pass

upwards into arenaceous shale. Carbonate forms a common constituent of this fonnation

and occurs as a isolated, coarse, angular fragments in the sandstone.

3.5.2.2 Arangi formation: These are formed as side slope of the main ridge of the

Patherwa formation. This consists of an alternating sequence of dark grey and

carbonaceous shales with lentia.dar carbonate and minor pseudo-conglomerate beds. The

formation at its top contains silicified beds and a hematitic regolith in the Kajarahat and the

Patherwa nala sections. The presence of the regolith is significant as it indicates exposure

and leaching of the underlying beds after deposition.

3.5.2.3 Kajarahat limestone: This unit overlies unconformably over Arangi Shale

formation (Prakash, 1967). These are exposed as linear structural hills, residual hills and

inselbergs protruding in the weathered pediment plain in and around Obra, Kajarahat, Billi,

Dala, Kota, Dyotara village.

On satellite image, it can be seen with greyish brown, yellowish grey to white tone at

mining site. The formation comprises predominantly of limestone with dolomitic limestone/

dolomite towards top of the sequence. The outcrop pattern is reflected by strike of bedding

occurring as ruwares, inselberg and tors.

Kajarahat limestone in the Billi-Obra section is microcrystalline, light grey, bluish grey to

buff in colour generally forming well bedded smooth outcrops. These limestone have a

southerly dip of 12° or more even occasionally vertical. In the Kajarahat, Billi section it is

folded into anticlines and synclines.

34

Geology of the Area

At places in the triangular outcrop near Billi where interconnecting joints are predominantly

developed, intense solution action and local internal drainage can be seen.

3.5.2.4 Porcellanite Formation: It is well exposed all along the southern part of the river

Son in and around Bari, Gauradah as residual hills. These residual hills on satellite image

show brownish grey tone.

The Porcellanite formation contains volcanic products which were presumably

contemporaneous to the Malani volcanics of the western Rajasthan (Kumar, 1985). These

are fine grained, greyish white rocks, characterised by two sets of major joints. After

breaking, it gives out conchoidal fracture with extremely fine shaped slinters.

Railway line cutting between Chopan and Billi exposes an excellent section of Porcellanite.

Moving from Billi towards Chopan, one can observe a complete section of Porcellanite

formation. The contact between Kajarahat limestone and Porcellanite is gradational, the

limestone imperceptibly passing into Porcellanite with the gradual increase in chert.

Occurring as interbands within Porcellanite, near Bari, is dolomite, showing elephant- skin

weathering. Towards the top of the sequence in the railway section banded Porcellanite is

seen. It comprises of silcified laminae showing well developed bedding defined by

alternating light and dark coloured layers.

Locally bands of green Porcellanite are seen in the Chopan-Obra road section, north of

Billi. The green Porcellanite is more cherty than banded Porcellanite and is free from

allogenic constituents.

3.5.2.5 Kheojua formation: It consists of three subdivisions viz. Olive shales, fawn

limestone and glauconitic beds. These are indistinguishable on satellite image.

Oliw! slr.ales: These pale olive green shale are exposed in the railway section north of level

crossing of Dala-Chopan road and in and around Chakaria village. In the railway section

the conformable contact between porcellanite and shales is present. The banded porcellanite

35

Geology of the Area

is succeeded by an alternating sequence of olive shales and subdued green semi-pelites. The

rocks are distinguishable from underlying porcellanite by their distinct colour, absence of

silicification and preponderance of allogenic material. The bedding in the shales is well

developed and is marked by bedding plane irregularities.

Fawn limestone: It is exposed along the Son river bank between Kandhaura and Chikra

villages. It is fawn in colour, siliceous and well bedded. Typical elephant skin weathering is

developed at the river bank near Chikra village.

Glt~~~collitic beds: It occurs as narrow belt and exposed around Sasnai village. The pale

green sandstone i~ silty in nature and characterised by the presence of glauconite. In

weathered surface, glauconite is oxidised to rusty brown iron-oxide (limonite) and the beds

show pale colour.

3.5.2.6 Rohtas limestone & shale formation: It forms the uppermost horizon of the

Semri group (Lower Vindhyan) and consists mainly of grey coloured, siliceous limestone

interbedded with thin shale. A road laid down by U.P. Forest Department runs in the

eastern and western part of it.

3.5.2. 7 Kaimur group: It forms the lower most horizon of the upper Vindhyan. The

K.aimur group is mainly arenaceous in nature and is subdivided into Lower Kaimur and

Upper Kaimur. The former includes lower quartzite, silicified shales and upper quartzite.

and the latter one consists of scarp sandstone and Dhandraul quartzite.

Lower Kai~t~~~r quartzites and Bijaigarh shales: The sandstone is silicified in nature and

light grey in colour. It is well jointed. The Bijaigarh shale is exposed all along bottom of the

scarp sandstone forming gentle scarp face. It is dark in colour and support sparse

vegetation.

Upper Kai~t~~~r SCtli'Jl sandstone and Dhandraul qutlrlzite: The scarp sandstone form

steep scarp face. The scarp sandstone is well jointed and support very little vegetation. The

Dbandraul quartzite lies over the scarp sandstone. It also forms wide plateau top with

36

Geology of the .Area

minor scarp. The plateau at a few places, after erosion gives rise to mesa form. It is fine

grained and thickly bedded.

3.6 STRUCTURE

The area studied depict various diastrophic structures such as antiform, synform, minor

folds, lineaments, faults, shear zone, fracture, joints and other structural elements.

Dominant structural features brought out from interpretation of satellite image of IRS-ffi­

LISS-ll and by digital image processing. The synoptic view provided by the satellite images

has helped in bringing out the regional geological and tectonic frame work of the area as

well as its lineament fabric.

During the field work, other structural details like bedding, foliation, dip and strike, joints,

minor fold and faults, shears etc. were studied.

3.6.1 Lineaments

3.6.1.1 A lineament is a mappable linear or curvilinear feature of a surface whose parts

align in a straight or slightly curving relationship that may be the expression of a fault or

other line of weakness. The surface features that make a lineament may be geomorphic or

tonal. Straight stream valleys and aligned segments of valleys are typical geomorphic

expressions of lineaments. A tonal lineament may be a straight boundary between

contrasting tone or a stripe against a background of contrasting tone. Differences in

vegetation, moisture content and soil or rock compositions account for most tonal

contrasts (Sabins, 1987).

3.6.1.2 Lineament Analysis: Lineament traces have been visually interpreted and

delineated from the satellite data (IRS LISS II FCC and digitally enhanced images). The

lineament map is shown in Plate 3. lb. Lineament density map and lineament intersection

density map have been prepared using the lineament map by counting the number of

lineaments and lineament intersections respectively within 1 km square grids and

contouring the values (Plate 3.2a and 3.2b).

37

Plate 3.2a : Lineament Density Map

Plate 3.2b : Lineament Intersection Density Map

Geology of the Area

For the purpose of lineament analysis, the lineaments were grouped into azimuth classes

corresponding to 10° intervals and the number and total length of lineaments within each

azimuth classes were measured (Table 3.4). Using these data frequency - azimuth and

length-azimuth diagrams were prepared as rose diagrams (Figures 3 .1 and 3 .2).

4.6.1.3 Results of lineament analysis: The lineament map (Plate 3.1b) shows high

correlation of lineaments and their intersections in the central part of the study area within

the Parsoi formations of the Mahakoshal group of rocks that consists of phyllite-schist with

alternating greywacke quartzite which form ridge-valley landforms. This is also evident

from the lineament density map (Plate 3.2a) and lineament-intersection density map (Plate

3.2b). High concentration pockets of both lineament density and lineament intersection

tlensity are also observed in the Vindhyan terrain in the north-western part coinciding with

the Kajrahat limestone. Though the lineament density girdles do not show any distinct

trend, the lineament intersection density map shows the anomaly girdles trending NW -SE

and NE-SW directions.

In the lineament map the following four prominent lineaments have been traced, apart from

a net work of minor lineaments.

i) The E-W lineament in the southern part coinciding with the boundary between the Lotan

and Parsoi formations which is geomorphologically represented by a strike valley

separating the two.

ii) The E-W lineament in the northern part marking the boundary between Mahakoshal

group and the Vmdhyan supergroup of rocks, which has been interpreted as a fault and

represented by a linear structural hill.

iii) The NW -SE lineament in the central part which intersect the above lineament.

iv) The E-W lineament along the Son river in the NE part. Its traces are seen further west

in the form of discontinuous lineament.

39

Geology of the Area

Table 3.4

STATISTICS OF LINEAMENT ANALYSIS

Azimuth Range Frequency Length Frequency

(km) (%ge)

0-10 22 81.5 9.13

10-20 14 46.75 5.81

20-30 13 45 5.39

30-40 27 95 11.20

40-50 23 90 9.54

50-60 23 80.5 9.54

60-70 10 33 4.15

70-80 5 24 2.08

80-90 4 22 1.66

90- 100 1 15 0.42

100- 110 5 22.75 2.08

110- 120 9 23.5 3.73

120- 130 14 63.5 5.81

130- 140 20 84 8.30

140- 150 17 62.5 7.05

150- 160 13 40.25 5.39

160- 170 13 57.75 5.39

170- 180 8 31.75 3.32

40

l I I I I

Fig. 3-1 LINEAMENT FREQUENCY AZIMUTH ROSE DIAGRAM

1 0 1 2 J '- SliM

Fig. J.2 LINEAMENT LENGTH AZIMUTH ROSE DIAGRAM

Geology of the Area

The azimuth-length and azimuth-frequency rose diagrams (Figures 3.1 and 3.2) show three

major directions of lineaments tn the area. They are,

i) NE-SW (varying between N30-60E)

ii) NW-SE (varying between N30-60W)

iii) N-S.

The formations in the area exhibit conspicuous E-W trending tight folds with steep axial

planes, indicating that the greatest principal axis of stress that has caused deformation was

along N-S direction, and the least stress axis along E-W. The NE-SW and NW-SE oriented

lineaments thus represent conjugate set of shear fractures resulting from .this stress. The N­

S set of lineaments represent the extension fractures along this direction.

4.6.2. Other tectonic structures: This has been dealt separately for major lithounits of

Mahakoshal group and Vindhyan supergroup.

4.6.2.1 Tectonic structures in Mahakoshal group of rocks:

i) Foliation: There are two directions of cleavage planes found as S2 and S3 cleavage

planes.

S1 cleavage: This is the axial-plane schistosity of Fl folds in the area, manifested by

preferred orientation of sheet minerals (Sericite, chlorite and biotite) with their flat faces

parallel to schistosity.

SJ cleavage: It is the axial plane cleavage of F2 folds and is developed as slaty cleavage.

Locally in the outcrop ofLotan formation, this cleavage is pervasive and has obliterated the

earlier s2 cleavage.

ii) Shears: Minor displacement along different sets of joints and fracture planes have been

observed locally resulting in thin zones of brecciation and development of slickenside. ln

the section examined near Gurmura railway station, two sets of shear trending WNW-ESE

are well exposed, one set displaying dip sub-vertically to south and the other at 20° to 30°

towards south.

42

Geology of the Area

iii) Joints: The joints in Mahakoshal group of rocks are mostly tight. Following sets of

joints have been observed in the field.

Orientation of Joint Sets

Strike

1.) N-S, dipping 80°W to 80° E

2.) E-W, two sets dipping 45° Nand 70° S

3.) NNE-SSW: vertical

4.) NNW-SSE: vertical

5.) NW-SE: vertical

6.) ESE-WNW: vertical

iv) Folds: These formations are tightly folded with E-W trends and dipping steeply to north

or south and forming linear ridge and valley topography, with synclinal hills and anticlinal

valleys.

v) Faults: The Mahakoshal group have clear faulted contacts striking EW with the

Vindhyans in the north as well as with migmatite in the south. Along the fault zones, fault

breccia is observed. The fault plane runs along the stream course.

3.6.2.2 Tectonic structures in Vindbyans: The lower Vindhyans are subjected to more

deformation than the upper one. The structural deformation in the Semri group of rocks

were observed in the field.

i) Joints: The Porcellanite formation is highly jointed and two sets of joints are more

prominent.

• Striking N 70° W- S 70° E and dipping 700 to SSW

• Striking N 30° E - S 30° W dipping 75° to SE

The hexagonal block of Porcellanite of different sizes indicate columnar joints. The vertical

joints are very common in Dhandraul quartzite and scarp sandstone. The prominent joints

in Dhandraul quartzite are:

l)WNW-ESE 2)NE-SW 3)NNW-SSE 4)NW-SE

43

Geology of the Area

ii) Fohls: These are seen on mesoscopic and macroscopic scales in the porcellanite near

Billi and near the railway crossing of Dala-Chopan road. These are flexural type of fold,

where southern limb of syncline is having relatively higher inclination.

iii) Ftllllts: The contact ofVmdhyan and Mahak.oshal is faulted one. The continuous hill of

folded Porcellanite occupying south of the river Son is faulted along N75°W-S75° E,

showing displacement with its eastern block as upthrown side. The Semri and Basal

formation is faulted near the village Hardi, displacing the Kajarahat limestone.

3. 7 Mineral Resource of the Area

The rocks and minerals of economic significance in the area are as follows (Plate 3 .3a)

1) Cement grade limestone: Extensive deposits of cement grade limestone exists within

the Kajarahat limestone horizon of the Vindhyan. Locally, it is being worked for

manufacturing of cement at Data.

2) Chemical grade marble: The marble band of Mahak.oshal near Ningha is milky white,

apparently free from deleterious impurities. It is suitable for chemical industries. Presently it

is also fed along with Kajarahat limestone to Dala cement factory to upgrade the grade of

limestone required.

3) Flux grade dolomite/limestone: Its deposits exist in the Kajarahat limestone horizon

towards the top of the sequence near its contact with Porcellanite beds. The flux grade

dolomite of this horizon near Bari is being exploited by U.P.S.M.D. Corporation.

4) Road materials: Low grade dolomite and Porcellanite are being used as road metals in

the area.

5) Old gold working: Evidence of old gold workings associated with quartz veins located

about 2.5 km ofGunnura (Dwivedi et.al., 1995).

6) Radioactive minerals: Preliminary investigation by AMD has indicated the presence of

radioactivity in the matrix of basal conglomerate, near Jhingdandhi granite exposure, which

has probably acted as the source (personal communication). In the Parsoi formation also,

radioactivity has been reported within mineralised green colour rocks and highly pulverised

smoky quartz. (Khan et.al, 1989).

44

! UMESTONE (CEMEt•T GRAOE1 MAR81.E (CEMEriT CJ1'1AOE 1 UMI!SlOfll! II DOLOMITE tFLU l'IOAO MATER1ALS OU> QOLO WQR~UG RAOIOACTI\IE IIAIUI:RAI.fl

Plate 3.3a : Mineral Resource Map

Plate 3.3b : Dolomite Mines near Bari Village

Geology of the Area

3.8 SUMMARY OF THE RESULTS

• VISU81 interpretation of standard FCC image (FCC 432) and digitally enhanced

products together with geomorphological features, drainage pattern and

landusellandcover features were found tob useful in delineating and demarcating

various litho boundary in the area.

• The area is occupied with two distinct geological formations: (1) Schist, phyllite and

quartzite sequence of Mahakoshal Group of rocks exposed in the southern part of the

area; (2) the sedimentary seq~ of rocks of Vindhyans are conspicuous by their

presence on either side of the Son river. The Semri group of rocks of the Lower

Vmdhyans are well exposed on the south of the Son river and along the northern bank.

The Kaimur group of rocks of the Upper Vmdhyan stands out prominantly to the north

of the area fonning high hills with steep scarp faces. Dhandraul quartzite, the upper

most formation of Upper Kaimur in the area forms plateau and covers northern fiinge.

• The Mahakoshal Grooup have clear faulted contact with the Vmdhyans. Rocks of

Mahakoshal Group are tightly folded with E-W trend and dipping steeply(~ 70°) due

north or south fonning linear synclinal ridge and anticlinal valley.

• The Lower Vmdhyans have been subjected to more deformation than the upper one.

• Major lineaments of the area not only shows the tectonic structure, but also demarcates

the major litho units boundary between Semri Group with Mahakoshal Group and

Parsoi Formation with Lotan Formation.

• The azimuth-length and azimuth frequency rose digrams show three major directions of

lineaments in the area: (I) NE-SW (varying between N30°- 60°E); (ii) NW-SE (varying

between N30°- 60°W) and (iii) N-S.

• The major mineral resources of the area are: cement grade limestones, chemical grade

marble, flux grade dolomite/limestone, road metals, possible mineralization of gold,

other base metals and radioactive minerals.

46