CHAPTER - III

GEOLOGICAL FRAMEWORK OF THE KACHCHH

GEOLOGICAL SETUP

T
LITERATURE REVIEW

he Kachchh region attains special position in Indian stratigraphy owing to the

presence of strato-type sequences of Mesozoic (Jurassic) and Cenozoic eras. First
report on Geology of Kachchh was produced by Grant (1837) with different maps and list
of fossils. Although the report was too generalized it has provided platform for further
investigations. Blanford (1869) was the first who presented proper ideas about the
geological architecture of the region. He envisaged presence of E-W trending faults along
the northern margin of major uplift of the basin. Wynne (1869 & 1872) published the first
report, along with a map, on the geology of Kachchh. The classification proposed by him
was broad based and he divided the sequence into two units viz. the Lower Jurassic
(marine) and Upper Jurassic (non-marine). Stolickza (1871-1873) based on
palaeontological, physical and geological relationships has established four stratigraphic
groups namely Pachchham, Chari, Katrol and Umia in ascending order. Waagen (1875)
studied in detail the fossil ammonites, and endorsed four fold classification put forth by
Stolickza. However, according to him, the Pachchham, Chari, Katrol and lower part of

32
Umia corresponded with the “Lower Series” and the upper part of the Umia with the
“Upper Series” of Wynne (1869). Latter, Oldham (1893) modified Waagen’s
classification and included the beds of Ukra hills into Umia Series.

A significant contribution on the Jurassic rocks of Kachchh was made by Rajnath (1932),
who on the basis of study of ammonites, lamellibranches and plant fossils established a
succession somewhat different from the previous ones. He restricted the term ‘Umia’ only
to the lower Umia of Waagen; the upper Umia made up of non-marine beds with plant
fossils was named by him as Bhuj Series of Middle Cretaceous or even slightly younger
age. He further investigated in detail the Jumara dome section in western Kachchh and
described 26 beds from Chari and Pachchham Series. He also re-grouped the Katrol series
of rock, into three main Stages namely - Lower, Middle and Upper, exposed respectively
in Walakhawas, Katrol, Katrol hill and Gajansar areas. He further observed that in the
Gajansar area, the Upper Katrol beds rest directly over the Chari beds. He re-defined
Umia Series and created a fifth stratigraphic unit – the Bhuj Series.

Agrawal (1957) mapped the Jhura Dome area and suggested a few changes in
stratigraphic nomenclature based on bio-stratigraphic such as, “Habo Series” for the Chari
Series and Mebha Oolites for the Dhosa Oolite Stage. Pascoe (1959), has compiled all
available palaeontological and stratigraphic data in his book entitled “A Manual of
Geology of Kutch”, mainly based on the work of Geological Survey of India, which is
still considered to be the best available account of the Geology of Kutch.

Poddar (1964) presented a summary of the geology of Kutch based on the work carried
out by the Oil and Natural Gas Commission. The four sub divisions of Jurassic
stratigraphy, which were described as ‘Series’ by Rajnath (1932) and Pascoe (1959), were
re-defined as ‘Formation’. Spath (1927-1933) based on his detailed study on fossil
content of respective lithology, subdivided the lower Jurassic. Subsequently, Rajnath
(1932) has established numbers of unconformities within the Jurassic strata, on the basis
of his detailed investigations on sea level oscillations. His study has further revealed that
there was a close faunal relationship between Jurassic of Kachchh and Madagascar due to
connectivity of Kachchh Sea and the sea to the south. Subsequently in depth studies
carried out by Biswas and Deshpande (1968) have generated the most authentic and
detailed maps on the geology and morpho-tectonic aspects of the Kachchh.

33
Hardas and Merh (1968) initiated the work on Quarternary Geology of Kachchh, and
have provided a first account of the Milliolitic rocks exposed along the coastal tracts and
inland areas of Kachchh. There are isolated occurrences of a distinctive variety of
Foraminiferal Sandstones all over Kachchh. These sandstones are similar in lithological
and biological characteristics as those of the so-called “Miliolite Limestones” of
Kathiawar (Fedden, 1884). The Miliolite Limestones are believed to be of marine origin
deposited during the Pleistocene period (Fedden, 1884, Auden, 1952, Krishnan, 1960,
Shrivastava, 1968a, Hardas and Merh (1968). Latter Hardas (1969) gave a detailed
account of sedimentology and structure of the area to the south of Bhuj. The most recent
Palaeontological and Bio-stratigraphic studies of the Kachchh Cratonic mass is credited
to the workers of ONGC (Ghosh and Ghosh, 1959; Sengupta, 1959; Guha, 1961; Poddar,
1963; Biswas, 1965, 1971; Biswas and Raju, 1971).

Biswas (1970) has subsequently revised the Mesozoic stratigraphy of Kachchh.

According to him the earlier suggested four fold classification did not fit in the modern
stratigraphic concept. Further the variation in litho-facies from one part of the basin to the
other and the detached fault-bound outcrop areas separated by covered plains made it
difficult to trace a set of rock units recognized in one area strike wise to the other areas.
This prevented the use of a uniform rock unit sequence throughout the basin and created
inter-basin correlation problem. He therefore recognized three main lithologic provinces
within independent classification. Biswas (1982, 1987) gave an outline of the structure
and tectonic evaluation of Kachchh basin and put forth the concept of monoclinal flexures
and domes aligned along the margin of all the major faults of the region i.e. Nagar Parkar
Fault (NPF), Island belt Fault (IBF), Kachchh Mainland Fault (KMF) and Katrol Hill
Fault (KHF). According to him the structure of Kachchh region can be correlated with
that of Laramide structures of Colorado Plateau and Central Montana Rockies of North
America. He attributed the genesis of these chains to the vertical uplift along almost
straight Master Faults.

The first work on the Tertiary of Kachchh which was neglected till then is credited to
Nuttle et.al. (1925), who has studied the Oligocene Nummulites of Kachchh. Since then a
great deal of micro-palaeontological work has been made. Significant studies on the
Tertiary bio-stratigraphy of Kachchh have come out after the works of Mathur (1963,
1966), Venkatachala (1968a) and Prasad (1984).

34
Platt (1962) has provided an over view on the sediments of the Rann of Kachchh which
was mainly based on the published accounts by Lyell, (1853) Wynne, (1872) Oldham,
(1917) and others. Biswas (1965) had suggested a time stratigraphic classification of the
Tertiary rocks based on the detailed bio-stratigraphic study (mainly micro fauna) and the
systematic mapping of the Tertiary rocks. Based on detailed study on Ammonite in Keera
and Jura dome area bio-zonation of Middle-Late Jurassic sediments has been worked out
by Prasad (1998) and he has proposed six assemblage zones within the Middle and Late
Jurassic sediments.

Besides stratigraphic, tectonic and palaeontological aspects other geological aspects of

Kachchh have remained center of attraction due to its seismic sensitivity. Earthquake
history has been deeply studied by workers like Wynne (1872), Oldham, (1893); and
Davison, (1936). They had worked out about 4.20 m subsidence of the southern side and
complete submergence of Sindree fort (located about 10-15 km south of Allah Bund) due
to 1819 Allah Bund Earthquake. A comprehensive compilation of earthquake data for
whole of the Indian shield has come out after the works of Baker (1846), Frere (1870),
Oldham, 1926), Quittmayer and Jacob (1979). Recently, Johnston and Kanter, (1990);
Bilham, (1998); Rajendran et.al, (1998) have worked out models on probable mechanism
of 1819 Allah Bund Earthquake. All these workers believe that the fault that ruptured in
1819 was of the reverse nature. However, a lot of ambiguity exists in the postulated
models presented by these workers.

Thakkar, et.al. (1999) has dealt geo-morphological accounts of Kachchh and Quaternary
tectonic history and terrain evaluation of central Kachchh Mainland. Karanth (2000),
Sohoni (2001 and 2002), Malik et.al. (2000 and 2001) have dealt with tectono-structural
attributes of central Kachchh Mainland with special emphasis on active tectonics and
Palaeo-seismicity. As per these workers present seismicity of Kachchh is manifestation of
continued tectonism, mostly along pre-existing planes of weaknesses (faults, major joints
etc). They have recorded eight active faults in the Kachchh region viz., Nagar Parkar
Fault, Allahbund Fault, Kachchh Mainland Fault, Katrol Hill Fault, Naira River Fault,
Bhujpur Fault and Wagad Fault.

The 26th January 2001 earthquake of Kachchh has attracted large spectrum of earth
scientists on tectonic aspects of the region. Gupta et.al., (2001), Shanker and Pande
(2001),Gaur (2001), Singh et.al. (2001), Karanth et.al., (2001), Biswas and Khatri (2002)

35
have worked on different aspects like location of epicenter, magnitude of waves,
movement and ground deformation caused by earthquake, aftershock monitoring, and
various other impacts. These studies have thrown light on occurrence of 26 January
earthquake in the Kachchh Rift basin, which is included in Zone - V of the seismic
Zoning Map of India (GSI, 2001).

LITHO-STRATIGRAPHY

The Kachchh stratigraphy which is represented by a complete sequence of strata ranging

from Middle Jurassic to Holocene and its richness in fossil assemblage remained an
intrigue issue for earth scientists. A period of non-deposition, followed by diastrophism,
erosion and volcanism during the close of the Upper Cretaceous time separates the
Mesozoic and Cenozoic rocks of the Kachchh. Igneous activities mostly volcanism, is
represented by Deccan Trap lava flows. The Mesozoic system of the region shows
sediments ranging in age from Bathonian to Santonian (Biswas, 1970). The Tertiary
includes Palaeocene to Pliocene sediment sequence and the Quaternary consists of
Pleistocene and Holocene sediments. The fault-related uplifts and consequent folding
have affected the Mesozoic strata. The Mesozoic rocks are surrounded by strips of gently
dipping Tertiary strata forming peripheral plains, which wrap round the Mesozoic
structures Biswas (1980, 1982, and 1987). A brief appraisal on overall litho-stratigraphy
of the Kachchh region is given as under.

Pre Cambrian Basement

The syenite rocks believed to be equivalent to the Pre Cambrian Erinpura Granite has
been considered to be the base of the Mesozoic rocks and is exposed only in the Meruda
Hill in the Great Rann, which is situated at about 25 km north of Khadir Island (Biswas
and Deshpande, 1968). A bed comprising graintic boulder conglomerate exposed at
Cheriya bet i.e. the northern most point of Khadir island is the oldest bed exposed,
marking the beginning of the Mesozoic sedimentation in Kachchh on a Precambrian
basement (Biswas and Deshpande, 1970).

Mesozoic Rocks

The Mesozoic rocks ranging in age from Middle Jurassic to Lower Cretaceous occur
noticeably in the various major uplifts, and are exposed extensively in the Kachchh

36
Mainland, Wagad, and the islands of Pachchham, Bela, Khadir, and the Chorar hills (Fig.
3.1). The Mainland outcrops are exposed as a continuous succession from Bathonian to
Santonian. The oldest sequence from Bathonian to Callovian is recorded in the Island
Belt. In Pachchham, Bathonian to Callovian rocks are exposed, while in Khadir, Bela and
Chorar, Bethonian to Oxfordian sequences have been recorded; whereas in Wagad the
intermediate sequence, from Oxfordian to Protlandian have been recorded. The earliest
and the acceptable Mesozoic stratigraphy of the Kachchh region was put forth by
Krishnan (1968) based on index fossils (Table 3.1)

The Mesozoic stratigraphy of Kachchh was subsequently revised by Biswas (1971). He

modified the earlier four-fold classification (Krishnan, 1968) in accordance with the
International Code of Stratigraphic Nomenclature. He recognized three main lithologic
provinces within the basin and rocks of each province were classified separately (Table
3.2). He further attempted correlation between the three sets of rock unit sequences to
bring out the overall stratigraphic relationship of the total basin. The units were named
according to the carefully chosen strato-type sections.

Deccan Trap Effusives: The main characteristic of the Deccan Trap in the region is
basaltic Lava flows, intrusive and inter-trappean beds. Exposures of Deccan Trap are
limited to Kachchh Mainland where it borders the Mesozoic highlands extending from
Lakhpat in the west to Anjar in the east (Fig. 3.1). Tholeiitic basalt is dominant lava flows
occupying the southern and southwestern slopes of the central highland and overlies the
Jurassic sandstone.

The Deccan Trap rocks form a more or less linear outcrop extending across the Mainland
with a maximum width of about 10 km in the east near the Anjar town and gradually
tapering westward. In the western part of the Kachchh the traps form an inlier within the
Tertiaries. The distribution and extent of trappean rocks in Kachchh appear to have been
controlled by the pre-trappean topography.

37
 68º

69º

70º

71º
GREAT RANN OF KACHCHH
24º 24º

Khavada #

Bhuj â

23º 23º
Kachchh Mainland
N
Recent & Pliestocene Quaternary System

º
Vinjhan Stage Kankavati Series
Khari Series
º

Aida Stage Bermoti Series Tertiary System

Berwali Series 10 0 10 20 30 Kilometers
Madh Series
Intrusives Deccan Trap
Bhuj Formation Pachchham Island Eastern Kachchh
Jhuran Formation Gora Dungar Formation Wagad Sandstone Formation
Khadir Formation Mesozoic System
Jumara Formation Kala Dungar Formation
Washtawa Formation (After Biswas and Deshpande, 1970)
Jhurio Formation
22º 15' 22º 15'
69º

70º

71º
Fig. 3.1 Litho-Stratigraphic Sequence of the Kachchh Region
38
 Table 3.1 Bio-stratigraphic Succession of Mesozoic Rocks in Kachchh Region
Formation AGE SUB-DIVISION LEADING FOSSILS
Post-Aptian Bhuj beds (Umia Plant Palmoxylan in upper beds Ptylophyllum
beds) Sandstones and flora, similar to Jabalpur flora in lower beds
Shales Australiceras, Colombiceras, Cheloniceras,
Aptian Ukra beds-Marine Tropachum
(1000 m) calcareous shales Unfossiliferous
Umia

U. Neocomian Umia beds; Barren Trigonia

sandstones and shales, Un fossiliferous
Valanginian Trigonia beds Virgatosphinctes, tychophyllo0ceras,
U. Tithonian Barren Sandstones Micracanthoceras, Hemi-lytoceras,
Umia ammonite bed Umialites, etc.
M. Tithonian Up. Katrol Shales Hildoglochiceras, orsoplanites Haploceras
Belemnopsis, Streblites, Phylloceras
Hildoglochiceras Aulacosphinctoides,
M. Tithonian Gajansar beds Virgatosphinctes
Waagenia, Katroliceras, Pachysphinctes,
L. Ththonian Uppar Katrol (barren ) Aspidoceras.
Sandstone Torquatisphinctes, spidoceras,
(300 m)

M. Kimeridgian Middle Katrol (red Ptychophylloceras, Taramelliceras,

Katrol

sandstone) Streblites, Waagenia, Hybonoticeras.

Epimayaites, Prograyiceras, Ataxioceras,
M. Kimeridgian Lower Katrol (Sand- biplices, Prosophinctes, Torquatisphinctes,
stone, shale, marls) Trigonia

Up. Oxfordian Kanthkot sandstone

(Bimammaturn zone)
Up to L Dhosa oolite (green and Taramelliceras, Discosphinctes,
Oxfordian brown oolites Perisphinchtes, Mayaites, Epimayaites,
(Transversarium zone) Paracenoceras, Peltoceratoides,
Peltoceras, Orianoides
U. Callovian Athleta beds (marls and Perisphinctes, Indosphinctes, Reineckeia,
gypseous shales) Kinkeliniceras, Hubertoceras.
Anceps beds (limestones
and shales) Reineckeia, Sijvjiceras, Idiocycloceras,
Kellawaysites
M. Callovian
(360 m)
Chhari

Macrocephalites, Dolichocephalites,
Rehmanni beds (yellow Indocephalites, amptokephalites
M. Callovian limestone) Pleurocephalites, Belemnites.

M. Callovian
Macrocephalus beds
(shales with calcareous
bends, with golden oolite-
diadematus zone in the
upper part)
L. Callovian Patcham coral bed Macrocephalites, Sivajiceras, Precerites,
Thamnastrea, Stylina, Montlvaltia.
Macrocephalites, Trigonia, Corbula.
Pachchham
(300 m)

L. Callivian to Patcham shell limestone Corbula, Eomiodon, Trigonia etc.

Bathonian
Pacham basal beds (Kuar
Bet Beds)
(After Krishnan, 1968)

39
 Table 3.2 Mesozoic Chrono-stratigraphy of the Kachchh Region
1. Kutch Mainland
Time Scale Rock Unit & Lithology Depositional
Thickness Environment
Bhuj Upper: Coarser grained felspathic sandstone, pale brown to
Cretaceous Formation dirty while, friable, current bedded.
(Neocomian Lower: Brown and reddish felspathic sandstone with rhythmic Fluviatile to
to 400-900(+) alternations of grey kaolinitic shale, sandy shale and thin hard Deltaic
Santonian) m ironstone bands. Shale occassionally carbonaceous, and
Thickening contain plant fossils. In western Kutch tongues of marine rocks
to the west occur (Ukra Bed)
Disconformity
Jhuran Katewar member: Grenish sandstone with occasional Trogonia
Formation bands (exposed only in Ghuneri Mundhan area, W. Kutch)
Argovian to Upper Member: Mainlay pink and Yellow sandstone with Infra-littoral
Neocomian 375-850m minor shale. Middle Member (Rudramata shales): mainly grey
(Thickening shale with thin sandstone bands.
to the west) Lower member: shale and sandstone with thick calcareous
sandstone bands.
Callovian to Jumara Mainly Khaki and grey gypseous shale withthin marl bands.
Oxfordian Formation Highly fossiliferous formation. Upper part characterised by Sub-Littorals
300m shale with thin fossiliferous oolitic marl bands (Dhosa Oolite).
Upper: Bedded white limestone mainly pelmicrite and
Upper Jhurio pelsparite. Golden Oolitic bands occur in lower half. Sub-Littoral
Bathonian to Formation Middle: Golden Oolitic limestone and shale
Callovian 325m(+) Lower: Thinly bedded limestone shale and golden oolitic
limestone
II. Pachchham Island
Upper: sandstone. with minor shale.
Gora Dongar Middle: Shale and thin flaggy fossiliferous calcareous bands.
Callovian Formantion Lower: Alternation of sandstone conglomerate, red and green Sub-Littoral
150 (+) siltstone, and occasional shale, Locally Wedges of granite
pebble-conglomerate are seen
Kala Dongar Upper: Yellow massive sandstone with calcareous beds Litoral
Bathonian Formation Lower Part: Alternation of sandstone conglomerate, red and
500 (+) green siltstone and occasional shale beds, Locally wedges of
granite-pebble-conglomerate are seen
III. Eastern Kutch (Wagad, Khadir, Bela, and Chorar)
In Western Wagad: Upper part (Gamdau Member) brown Up. in Wagad
current bedded felspathic sandstone with ferruginous bands & Formation
Argovian ? Wagad and grey shale, locally contain plant fossils. Lower part in E. Wagad
to Albian sandstone (Kanthkot Member) shale and sandstone with marine fossils. are fluviatile
Fm: 400m to deltic.
(+) In Eastern Wagad : Brown and red felspathic s.st. with shale L in W.
beds and hard purple and black ironstone bands. Wagad is
marine sub-
litoral.
Washtawa Formation: Exposed in central Wagad only and
equivelent to the upper part of the Khadir Formation Consists
Bathonian to Washtwa of shale and s.st. alternation. Upper part fossiliferous.
Oxfordian 225m(+) Khadir Formation: Upper part mostly shale with minor s.st. Litoral to
Khadir interbeds. More s.st. beds appear towards the east (Gangta Bet infra-litoral
550m(+) and Desalpur area). Upper middle part: sandstone withthin
Formation shale beds. Lower middle part: L.st. with chert nodules. Lower
part: Massive sandstone and shale. Basal part: Grey arkose
with wedges of granite cobble-conglomerate.
(After Biswas, 1971)

40
The basaltic flows show gentle southerly dips and the formation wraps around the
western extremities of the Mesozoic strata. Six major flows have been reported at the
eastern extremity (Dhola hills near Anjar) where they show alternation of columnar and
amygdaloidal basalts occasionally separated by inter-trappean beds. As a result of
differential erosion on both columnar and amygdaloidal basalts the terrain shows alternate
valley and ridge type of topography. A maximum thickness of about 500 m is recorded in
the eastern part (Dhola hills) while it tends to decrease to almost 150 m in the northwest.
The flow gradually thin out northward and are practically absent further north in the
Island Belt and Wagad regions.

Deccan Trap is also represented by number of long narrow dykes that occur to the north,
northwest and northeast of lava flow occurrences. Most of the dykes occur along system
of faults trending N-S, NNE-SSW and NNW-SSE (De, 1981). The average length of
dykes is about 5 km but larger lengths to the order of 15 km are not uncommon. The
thickness of the dykes rarely exceeds 30 m (Hardas, 1969). An interesting aspect of the
Deccan volcanism in Kachchh is the occurrence of alkaline basalt and its derivatives as
plugs, laccoliths and sills. These are generally confined to the structural domes in the
Mesozoic. Laccoliths are common along the northern marginal faults of Kachchh
Mainland. Besides, a host of dykes, ring-dykes, cone sheets, commonly occur in the
Mainland, Wagad highland and in the northern island chain of faulted blocks. The
occurrence of plugs, cones and vents have been considered to be the main volcanic
centers along which the basaltic lava flowed (Biswas, 1982). Isotopic studies have
established an age range of 65 to 67 M.Y. for these alkaline rocks; the tholeiitic basalts
have yielded an age around 67 M.Y.

Laterites: In Kachchh, the laterites form a linear narrow belt extending for a few hundred
metres wide and several hundred kilometers long. Laterites have been considered to be
the Palaeocene age (Biswas and Deshpande, 1970) are exposed parallel to the Tertiary
rocks and sandwiched between the basalts of the Deccan Trap and the Tertiaries. The top
most lateritic layer contains large reserves of economically workable bauxite.

Cenozoic

Tertiary Rocks: Kachchh is considered to be the ‘Type Area’ for the marine Tertiary
Rocks of India where a more or less complete sequence has developed. The Cenozoic

41
rocks ranging in age from Palaeocene - Pliocene occur in Kachchh as narrow strip
fringing the Mesozoic outcrops of the highlands. The Cenozoic rocks best developed in
the coastal strips of southern and western part of Kachchh Mainland. However, the
maximum thickness of these rocks has been observed in the southwestern part of the
Mainland. Tongues of Tertiary rocks are seen to extend through the lows of the
Mesozoic-Trap depositional platform. These lows are in fact synclinal troughs that have
been eroded and acquired the position as valley flats in post Trappean times (Biswas,
1965).

Table 3.3 Chrono-stratigraphic Succession of Tertiary Rocks of Kachchh

Period Age Series Stage
Pleistocene to Recent Deposits: Alluvium
Holocene Rann silts and blown sands
Miliolite Formation
-=-=-=-=- Unconformity -=-=-=-=-
Pliocene Kankavati Series
---------- Disconformity ----------
Miocene Helvation to Burdigalian Khari Series Vinzan stage
Aquitanian Aida Stage
---------- Disconformity ----------
Oligocene Chattian Wior Stage
Lattorfian to Rupelian Ber Moti Series ---Diastem---
Ramaniya
Stage
===== Paraconformity =====
Eocene Lutetian Babiya Stage
Berwali Series Disconformity
Ypresian Kakdi Stage
---------- Disconformity ----------
Paleocene Madh Series
-=-=-=-=- Unconformity -=-=-=-=-
Upper Cretaceous to Deccan Trap Formation
Paleocene
(After Biswas, 1970)

The Tertiary rocks are also seen to crop out as narrow strips bordering the southern and
western edges of Pachchham Island. The outcrops are discontinuous due to the
overlapping of the Recent alluvium. Continuous strips of Miocene rocks fringe the
southern margins of Khadir and Bela islands, the peripheral regions of the Wagad
highland and as small ‘bets’ in the LRK. Cenozoic litho-stratigraphy as worked out by
Biswas (1970) is given in Table 3.3.

42
Quaternary Deposits

So far very limited efforts have been made to study Quaternary history of Kachchh.
Therefore, Quaternary stratigraphy has not been properly recorded in Kachchh region.
The studies on the Quaternary aspects have been carried out by the workers viz. Roy,
(1973); Baskaran, (1989); Allahabadi (1986); Shrivastava (1971), Sharma (1990) and
Thakkar (1999). The oldest Holocene sediments possibly merges downward into terminal
Pleistocene sediment sequence comprising fluvio-marine to fluvial sediments that in turn
rest over a marine sequence that can be correlated with the Miliolite Formation of
Saurashtra (Allahabadi,1986). Exposures of Quaternary deposits are patchy and
characterized by fluvio-marine and aeolian accumulation all along the coastline, Rann and
in some inland areas. These include coastal marine sand and silt and aeolian miliolite
dunal accumulations within the highlands. The sediments of the two Ranns constitute the
youngest formation. However, following litho-stratigraphy (Table 3.4) has been
suggested for Quaternary system in Kachchh region.

Table 3.4 Quaternary Litho-stratigraphy of Kachchh Region

Period/Epoch Litho-Stratigraphy
Holocene Recent Alluvium and Silt Deposits of Rann area and blown sand
Pleistocene Upper to middle Duenal accumulation of Miliolite
Lower (?) Conglomerate and grit of upper Kankavati series
(After Merh, 1995)

Pleistocene: It is difficult to recognize lower part of the Pleistocene deposits, but it is

believed that the conglomerates and grit occur on the top of Kankavati series are probably
belong to early Pleistocene and they are well exposed in western Kachchh region along
the river Khari (Merh,1995). Lower and middle Pleistocene rocks of the area are
characterized by patchy occurrence of wind blown deposits of miliolitic formations.
Major miliolitic occurrences in the Kachchh region are found as obstacle dunes and sheet
deposits at the base ground of the hills and in the depressions, hollows and slope areas of
major hills and ridges of the mainland areas. Allahabadi (1986) has mapped miliolites
occurrences in the region and established that miliolites occurs at different altitudes and
based on this fact along with few evidences he indicated role of tectonism for its
occurrence at different elevation.

Holocene: Sediments of two Ranns and coastal mud flats along with sandy beaches of
Sub-Recent and Recent ages are recognized as Holocene deposits in the Kachchh region.

43
By and large all these deposits are characterized as unconsolidated formations.
Unconsolidated Sediments of Rann region are unique examples of Holocene
sedimentation. The Great Rann and Gulf of Kachchh are sites of deposition of early
Holocene sediments under estuarine deltaic environment. History of last 10,000 years has
revealed the role of two factors viz., glacio-eustasy and seismicity-related tectonism,
influencing the strandlines and fluvial sedimentation (Roy, 1973; Shrivastava, 1971).
Even today, linear trench zone of the Rann is annually inundated by marine water from
the Arabian Sea, whereas, Great Barren Zones in western part and Banni area of Rann are
flooded by surface run-off from the surrounding highland (Roy, 1973; Roy and Merh,
1977 & 1982). The Banni plain is made up of fluvial deposits and in all probability,
consists of a portion of an ancient delta that is now tectonically disrupted. The
surrounding area of Linear Trench Zone is flooded during supra-tidal time, which does
not go back to the sea and remains as under the conditions similar to salt playa
environment which, gives rise to permanent salt encrustation to the regions. The deeper
portions of the playa lakes are made up of unlayered, bluish grey and yellowish brown
oxidixed, silty gypseous clay with traces of mica. Towards the margins of the playas, the
sand percentage increases. Hence the gradual alternate layers of salt and silt with tidal
movement gets deposited in Rann area (Roy and Merh, 1977).

Next to Rann, other major deposition sites for Holocene sediments in Kachchh region are
coastal mud-flats and beaches. The Kachchh coastline was remained practically
uninvestigated till the work of Sharma (1990). According to him the Kachchh coast can
be divided into three segments viz.

 The western segment from Koteshwar in the north to Suthri in the south made up of
extensive tidal mud-flats and a series of off-shore sandbars.

 The central segment between Suthri and Bhujpur overlapping partly by the Arabian
sea and partly by the Gulf of Kachchh comprising sandy beaches, coastal dune ridges,
and a rocky platform.

 The innermost eastern segment between Bhujpur to Chirai falls within the Gulf, and is
characterized by featureless vast terrain largely comprises either tidal mud deposits or
saline wasteland merges into the Little Rann in further east.

44
He further concluded that these segments have reacted differently to the successive sea
level changes because of differential movements of fault-blocks along the old lines of
weaknesses. In addition he has also established resemblance of the coastal terrigenous
material with the Indus River sediments based on heavy mineral studies.

STRUCTURE AND TECTONICS

The different structural elements, which have played significant role in the post-Mesozoic
geological and geo-morphological evolution of the region, are recorded by various
workers like Srivastava et al., (1964); Biswas, (1980, 1982, 1987); Biswas and
Deshpande, (1970); Sychanthavong, (1984); Sharma, (1990) and Sohoni, (2002).
However, the significant contribution to define the tectonic framework and structures of
Kachchh region is given by Biswas, (1987). He described the structure of Kachchh region
as Peri-continental rift basin and formed due to rifting along Precambrian tectonic trends
and located at junction point of Sindh-Baluchistan geo-synclinal belt to Indian
Continental shield on northwestern margin. Therefore, various block faults and
consequent folds characterized mobility of this margin. This marginal zone is extended
from Bombay to Kachchh through Surat-Broach and Saurashtra peninsula and reaches its
maximum mobility near Kachchh where it meets with Sindh-Baluchistan geo-syncline.

The five principal faults trending east-west, along which the uplifts have taken place are
(01) the Nagar Parkar fault, (02) the Island Belt fault, (03) the South Wagad fault, (04)
the Kachchh Mainlad fault, and (05) the Northern Kathiawar fault (Biswas 1980). Among
these linear uplifts along the first four faults have given rise to four sub-parallel ridges i.e.
Nagar-Tharad, the Island Belt in the Great Rann of Kachch, Wagad and Kachchh
Mainland. The block faults are typical in the Pre Cambrian consolidated basement.
Whereas the Mesozoic strata show various asymmetrical domes and anticlines, second
order faults and igneous intrusions. The Tertiary strata striping the Mesozoic highs show
very gentle dips and overlie the eroded Mesozoic folds in some places, bearing testimony
of a major pre-Tertiary tectonic movement. Biswas (1982) has described the most striking
feature in the Kachchh region is meridional high in the middle of the basin transversely
across the basin and occurs along the hinge zone (Fig. 3.2). Evidence of sediment
thickness and the litho facies present indicate that this high came into existence in late

45
Oxfordian time. The thickness of accumulated sediments in western part of the high is
more and deeper in compare to eastern portion indicates variation in facies from shallow
marine to littoral and fluvial.

71º
70º
69º
Recent & Pliestocene Deposits
Tertiary
Deccan Trap
24º Mesozoic 24º
A L L A H B U N D F A U L T ? ?

PU KU BU CU

M
A I
N
L A WAGAD

H
N D UPLIFT

I G
F A U L T

H
M A I N L A N D
23º N 23º
A
Major Faults
I

Secondary Faults T
U L
D

Median High F A
a Dome
E

A R N

Ï A W
M

ÿ
Plunging Anticline T H
Plunging Syncline K A 20 0 20 40 60 Kilometers
(After Biswas and Deshpande, 1970)

71º
70º
69º

Fig. 3.2 Tectonic Framework of the Kachchh District

In addition to principal faults there are many second and third generation faults as well as
other structures have also been recorded by various workers within the Kachchh
Mainland, which developed during various stages of the repeated reactivation of the
major bounding faults at later stages (Srivastava et al., 1964; Biswas, 1980 & 1982;
Biswas and Deshpande, 1970; Sharma, 1990; Sychanthavong, 1984). These faults have
significantly influenced the Cenozoic landscape of the Kachchh. Among these some of
the important structures are Katrol Hill Fault, Vigodi Fault, Little Rann of Kachchh Fault
system, Naira River Fault, Bhujpur Fault, Vinjhan Fault, Vinjhan Anticlinal Nose and
Kothara Embayment, Gulf of Kachchh Embayment, Narayan Sarovar Anticlinal Nose,
and Bhachau Anticlinal Nose are important.

Folded strata of Cenozoic sediments along the Kachchh coast are typical evidence for the
fault movements of the various blocks under the sediment cover. The fault uplifts and
subsidence occurred more or less along the old lines of weaknesses. The draped strata of
Tertiary and Quaternary ages also reflect control of pre existing basement topography
given rise by Trap.

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Table 3.5 Region wise Structure and Tectonics of the Kachchh Region
Area Structure Description
Kachchh Major  ESE -WNW to E-W trending Kachchh Mainland Fault
Mainlan Boundary Northern Boundary Fault
d Uplift Faults  NW-SE trending Off shore West Coast Fault western boundary
fault
 Gulf of Kachchh Fault and the Little Rann of Kachchh Fault
System Southern and eastern Boundary trending NW-SE, NE-
SW and E-W
Other Second  Katrol hill (E-W) fault Vigodi faults (NW-SE) responsible for
and Third subsidiary up-liftment
generation  Naira River Fault (NRF) NE-SW and Bhujpur fault (BF) NW-
faults SE are transverse faults/structural lineaments, representing
reactivation of basement faults during Quaternary period
 Vinjhan Fault (E-W)
Dome and Half  Jara, Jumara, Manjal, Keera, Lyari, Chhari are the major
dome domes,
 Dhar dungar half dome
Anticline  Jhurio, Habo (SSW-NNE) are major Brachy anticlines
 Bhuj anticlinal nose (ESE-WNW), Bhachau Anticline nose
(ESE-WNW but E-W in center) eastern half of Lakhpat
anticline nose western half of middle anticline of Kachchh
 Vinjhan Anticline nose (E-W), Drag feature of Tertiary age
Syncline  Kothara Syncline (E-W), Narayan Sarovar nose
Wagad Major Faults  Northern faulted margin facing Rann along with flexures
Uplift  South Wagad Fault Trending NNW-SSE associated with
flexures and folds
 Another fault is Gedi fault marks boundary of Rav basin in
north
Dome Washtawa, Sarasla Dabundha, Chitrod domes
Anticline  Major anticline Kanthkot, Dedarwa, Gagodarm , Varnu, Vekra
Anticlines
 Brachy anticline of Kanmer
Syncline Badargarh Synclines
Pachchh Kala Dungar  W-E trending asymmetrical anticlines and synclines
am Flexure Zone  Various Domes with gabbroic plugs
Uplift  Kala Dunagar Edge fault (NNW-SSE) and various oblique
faults trending (NNE-SSW)
Gora Dungar  Northern Gora Dunagar Edge fault (ENE-WSW) and various
Flexure Zone secondary oblique faults trending (NE-SW and NW-SE)
 WNW-SES trending asymmetrical anticlines and synclines
 Central Valley Syncline between two flexures.
Khadir Structures  Half Dome sloping to the south with radial dip pattern
Uplift  Marginal Flexure and fault are covered by Rann Sediments
Bela Fault/Flexures  Northern Marginal fault flexure with parallel to Bela fault
Uplift  Southern marginal fault flexure, Desalpar-Fatehgarh Flexure
zone associated with Gedi fault
Fold  Central structural low, Balasar syncline
Rann of Major  Nagarparkar Fault and Island Belt fault
Kachchh Structures  Kunwar bet dome
 Linear Trench zone
(Compiled after Biswas, 1980 & 82 and Biswas and Deshpande, 1970)

47
There exists number of evidence corroborating different parts of the Kachchh Mainland
have undergone differential movements during Quaternary period. Even geo-
morphological evolution of coastline has been controlled by the periodic movements
along these tectonic lineaments. Sengupta (1967) has given fairly detailed account of the
off-shore faults of the Kathiawar and Kachchh. According to him, the northern coast of
Saurashtra represents a submergent coast. Considering this submergence against the
background of the nature of the emergent coast of the southern Kachchh along the Gulf,
indicates strong possibilities of the presence of sets of faults within the Gulf along which
such movement could have taken place. Ghosh (1981) based on his detailed study on the
Quaternary morpho-stratigraphy and neotectonic activities in Little Rann has also
mentioned many evidences to support several phases of tectonic movements from post-
Tertiary to the Recent times.

Based on above description present structure of the Kachchh region can be characterized
by series of late Cretaceous uplifts associated with plutonic bodies and intervening
Tertiary basins. The Kachchh Mainland, Wagad, Pachcham, Khadir and Bela are the
major uplifts of the region (Fig. 3.2). All these uplifts have occurred along the master
faults that has similar trends as that of Delhi tectonics. The uplifted margin of the faults
shows linear fold zones comprising of various asymmetric domes and brachy anticlines
associated with igneous activities, which can be seen through the presence of intrusions
such as laccoliths, plugs, sills, and dyke swarms in the area. Chronology of basinal Uplifts
and fault systems of the Kachchh region is given in Table 3.5.

48