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0016-7622/2011-78-4-299/$ 1.00 © GEOL. SOC. INDIA

JOURNAL GEOLOGICAL SOCIETY OF INDIAVol.78, October 2011, pp.299-320

Some Burning Questions Remaining Unanswered

K. S. VALDIYAJawaharlal Nehru Centre for Advanced Scientific Research, Bangalore – 560 064

Email: [email protected]

Abstract: Writing a book on the geodynamic evolution of India (Valdiya, 2010), which involved going through andperusing voluminous literature, I was confronted with many burning questions for which I could not find decisiveanswers. Maybe I missed the answers, or perhaps I failed to grasp and comprehend the logics of authors. I also felt thatmany very crucial problems of the evolutionary history of India await addressing squarely by the new generation of earthscientists. When the President of the Geological Society of India, Dr. Harsh Gupta, kindly invited me to speak at theAnnual General Meeting of the Society in October 2010 I could not suppress my urge to voice my ignorance throughsome questions that tantalizingly tease me.

57±3 Ma (Acton, 1999). Most of the earth scientistssubscribe to this view.

If the timing of the collision is taken at 55–50 Ma, thenquite a few questions have to be answered.

The fossils contained in the sedimentary rocks in theWaziristan–Khurram region in northwestern Pakistanindicate that the docking of the northwestern edge of Indiawith Asia took place nearly 65 million years ago (Beck etal. 1995; Zaman et al. 1999).

In the east in Cuofiang area in southern Tibet, Indiatouched Asia at about 68 Ma (Xiaoying et al. 1996). ThePalaeocene Liuqu Conglomerate, representing fluvialdeposits, occupies a tract entirely south of the Asia–Indiajunction, implying that the welding of the two continentstook place in the Later Cretaceous to Palaeocene time(Aichitson et al. 2002)

In the Maastrichtian time (70-65 Ma), a large variety ofvertebrate animals such as even-toed deers, turtles,crocodiles and fish made sudden appearance in the Murreesediments of the Kalakot area in Jammu, and these animalsbear remarkable similarity with those of China, Mongolia,Siberia and Central Asia (Ranga Rao, 1971; Sahni andKumar, 1974).

Some taxa belonging to palaeryctid mammals,crocodiles, pelepatid frogs, alligators, charophyteNemegtichara and ostracodes occurring in the UpperCretaceous (Maastrichtian) formation of Central India showstrong affinity — bordering on identity — with thecontemporary forms of Mongolia and China (Sahni, 1984;Bhatia and Rana, 1984; Jaeger et al. 1989; Bhatia et al. 1990;Sahni and Bajpai, 1991; Bhatia et al. 1996).

WAS IT COLLISION OR DOCKING OFINDIA WITH ASIA?

The geological literature is replete with mentions andaccounts of collision of India with Asia sometime between50 Ma and 68 Ma (Fig.1). In all my writings I have myselfdescribed the phenomenon of coming together of India andAsia as a collision. But was it a collision? To a commonman the word collision implies a violent impact, an accidentoccurring when something moving hits another.

India converged towards Asia ever since it broke awayfrom Africa. Just before it touched Asia, the speed ofmovement was 180–195 mm/yr; and this rate slowed downto 45 mm/yr (Klootwijk et al. 1992), implying the resistancethat the moving Indian plate encountered due to collision.

To recapitulate, just before the coming together of thetwo continents the rate of movement of the Indian plate was180–195 mm/year (or 0.49–0.53 mm/day) and after that itdecreased to 45 mm/yr (or 0.020–0.022 mm/hour).

When a continent moving at the rate of 0.49 to 0.53mm/hour slams another continent, would that incident becalled a collision? Is it not appropriate to call the event asthe docking of India with Asia?

WHEN DID THE DOCKING TAKE PLACE?

As already stated, India was moving northwards at therate of 18 to 19.5 cm/year just before the docking. Thensuddenly the speed slowed down to 4.5 cm/yr around 55million years ago (Klootwijk et al. 1992). The interpretationof global palaeomagnetic data has led some scholars toconclude that India’s movement abruptly decreased at

JOUR.GEOL.SOC.INDIA, VOL.78, OCTOBER 2011

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Fig.1. Upper: India converged towards Asia and its northwestern edge touched Asia. Inset shows a chain of volcanicislands, forming an arc between the two continents.Lower: The suturing of the island arc complex with the continents is explained by three models.(Based on various sources given in Valdiya, 2010).


SOME BURNING QUESTIONS REMAINING UNANSWERED 301

How come that non-marine assemblages of theMurrees of the Kalakot area in Jammu and also of theintertrappean beds at Asifabad and Takli in central Indiashow remarkable identity at the specific level with theMaastrichtian fauna of Central Asia, Mongolia andChina?

What could be the reason for the remarkably strongaffinity with the Indian faunal taxas with those of Asia inthe Maastrichtian time?

Unless a land bridge between Asia and India had formedin the early part of the Upper Cretaceous, there would nothave been any immigration from Asia to India (Figure 1upper).

Why are we not seriously working on the problem ofthe landbridge of faunal immigration from Asia to India?

Were there more than one land bridge?Why do we dare not — or interested not — to work on

the northern edge of the Himalaya, particularly to findout where else were the land bridges formed?

Even in the face of strong palaeontological evidence,we continue to accept the deduction based on palaeo-magnetic testimony that India touched Asia around 50–55 Ma.

Why are we hesitant to accept the fact that the dockingand welding of India with Asia took place in the period65–68 Ma?

It may be pointed out that the peak of the DeccanVolcanism occurred at 65.5 Ma. And there was persistentvolcanic activity in this period all along the periphery of theHimalaya (Valdiya, 2010).

Does it not imply that the stupendous volcanism thatoverwhelmed a large part of the Indian subcontinentwas in some way related to the docking of India withAsia?

PENINSULAR INDIA SLIDES UNDERTHE HIMALAYA

The Peninsular Indian crust bends down as it slides underthe Himalaya (Fig.2). The rate of slip varies from 20±3 mm/yr in the central sector to 10 mm/yr in the Salt Range sectorin the west (Wesnousky et al. 1999; Lave and Avouac, 2000).The GPS measurements confirm the variable rate of slip(Figure 2 inset) from 10–20 mm/yr in the Sikkim sector,10–18 mm/yr in the Uttarakhand sector to 14–20 mm/yr inthe western sector (Banerjee and Burgmann, 2001; Jade,2005).

Palaeoseismic studies indicate extensive rupturing ofthe crust in the immediate proximity south of the HimalayanFrontal Thrust/Fault — in B.C. 400 and A.D. 260, 800, 1294,

1423, 1500 and 1700 — in the belt between the Ghaggharin the west and the Kumauni Kosi in the east (Wesnousky etal. 1999; Malik and Mathews, 2005; Senthil Kumar et al.2006). In southern Nepal there was an event in A.D. 1100(Lave et al. 2005). And in northern Bihar many earth-quakes occurred sometime in 25,000 yr B.P., 5,300 yr B.P.and 1,700 yr B.P. (Sukhija et al. 2002).

It is also known that the ground of the Indo-GangeticPlain in northeastern Uttar Pradesh and adjoining Bihar(Fig.3 Upper) is sinking at the rate of 0.2 to 0.3 mm/yr asthe Survey of India benchmarks show (Sinha and Jain,1998). As a consequence, the rivers are migrating orshifting westwards in Bihar and eastern Uttar Pradesh, andeastwards in western Uttar Pradesh (see Valdiya, 2010 forreferences).

The Bengal–Bangladesh plains (Fig.3 Middle andLower) is cut by a multiplicity of faults, which are activeand causing sinking and uplift of the ground-surface — asmuch as 30 m uplift in the Madhupur region. The loci ofearthquakes are located along the active faults (see Valdiya,2010 for references).

If this is happening, why are we not studying inearnestness such geomorphological-structural changes asupwarping or bulging up and sagging or sinking of theground, just south of the Himalayan Frontal Thrust allalong its extent — along the line where Peninsular Indiais underthrusting the Himalaya?

Where are the structural–geomorphic humps or domesdeveloping, where are the sag ponds forming, and whereare the lands becoming seriously water-logged or swampy?

Where are rivers showing unambiguous signs ofderangement or shifting of courses?

Would it not be advisable to find out by geophysicalmeans whether and where subsurface blind faults or blindfolds are in the process of forming?

THE “LINEAMENTS”

The stupendous volume of lavas and volcaniclasticmaterial emplaced 61 to 69 million years ago — the DeccanTraps — is related to the Reunion Hotspot (De, 1981). Thepassage of the Indian plate over this hotspot caused domingup of the western part of the Peninsular India and resultantthinning, stretching and rifting of the crust (Sheth, 1999).The stretching and rifting is evident from the swarms ofparallel to sub-parallel dykes in the Konkan Belt and inthe Tapi-Narmada rift valleys (Fig.4). The average thicknessof dykes is 15 m, and on the average there are 7 dykes perkilometre along the Konkan and 20–25 dykes/km in theTapi–Narmada belt (Deshmukh and Sehgal, 1988). In a


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limited Rajpipla sector, the aggregate thickness of thedykes is more than 1.5 km. Imagine how much the Indiancrust must have stretched when the dykes were emplaced!

Although the dykes are believed to have served asfeeders of the Deccan lavas, the passage of the lavas todolerites of dykes is seen but rarely (Auden, 1949;Deshmukh and Sehgal, 1988).

Why are we not looking for more sites for studying thepassage of the dolerite dykes to the Deccan lavas?

What is the nature of the transition in terms ofmineralogy, texture and chemistry?

One of the most significant features all along theSahyadri, the Western Ghat and the Konkan–Kanara–Malabar Coastal Belt is the multiplicity of the so-called

lineaments. They trend persistently NNW–SSE to NW–SEand N–S (Figs. 4B, 7, 8 and 9). One would not dispute thecontention that these “lineaments” are expressions of thestretching of the Indian crust as it rode over the ReunionHotspot.

Many of these “lineaments” are associated with hotsprings (Figs.5 and 7) (Chadrasekharam, 1985; Shanker,1989; Srinivasan, 2002). The large number of hot springsaligned parallel to the coast all along the West Coast inKonkan and Kanara, (to which may be attributed the highheat flow value varying from 51.5±4.6 to 129±8.3 mW/M2

(Shanker, 1989), indicate not only the existence of faults,but also the fact that the majority of the faults reach greatdepths.

Fig.2. As the Indian shield (plate) slides under the Himalayan mobile belt — which is subdivided into four contrasted terranes — theterrane-defining thrusts became active time and again and with varying rate in different sectors (after Gansser, 1991). Inset: GPSmeasurements indicate northeasterly and easterly movement of India. The lengths of the arrows show the velocity, and theirtrends the direction of movement.



Fig.3. Upper: Ground surface of northern Bihar and adjoining Uttar Pradesh is subsiding, resulting in progressive shifting of rivers anddevelopment of swamps and lakes due to impeded drainage. (from Sinha and Jain, 1998).Middle and Lower: Built of Later Quaternary and Holocene sediments, the Bengal–Bangladesh plain is cut by a multiplicity ofactive faults. The section shows uplift of the ground along one of these faults (based on Morgan and McIntyre, 1959; Alam,1996).


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Quite many of the “lineaments” and fractures areseismogenic (Fig.6). This is evident from the pattern ofdistribution of epicentres lying in their close proximity asseen in the Mumbai–Bassien–Panvel sector (Fig.7 Inset) inthe Konkan (Srinivasan, 2002; Raghu Kanth and Iyengar,2006; Mohan et al. 2007), in the central part of the Sahyadri(Fig.8 Inset) in Karnataka (Sambandam et al. 1994; Valdiya,2001a, b) and in central Kerala (Fig.9) (Rajendran andRajendran, 1997; Rastogi, 2001; Singh and Mathai, 2004;Valdiya and Narayana, 2007).

The great depth to which they extend, the earthquakesthat they generate due to slipping on them at depth and theanomalous behaviour including ponding of the present riversand streams on their crossing them implying reactivation(Kundu and Matan, 2000; Valdiya, 2001a, Valdiya andNarayana, 2007) — together demonstrate unequivocally thatthe so-called lineaments are faults — active faults related

to the bulging up of the western part of the Peninsular Indiaand its stretching and rifting.

Very significantly, the fault-plane mechanism solutions(Fig.6 inset) demonstrate without doubt that these“lineaments” are indeed strike-slip and normal faults(Rastogi, 1992).

Why then we continue to describe them non-commitantly as lineaments? Why do we hesitate to call aspade a spade?

NATURE OF THE PALGHAT GAP

The Sahyadri is a 1600 km long mountain range.

How can one explain the nature of the Palghat Gap(Fig.12) which is 25–30 km in width and 45–300 m abovethe mean sea level in between two long and very high

Fig.4. The West Coast of India and the tract of Narmada–Tapi valleys are characterized by swarms of dykes–trending NNW/N–SSE/Sin the Konkan and E/ENE–W/WSW in the Narmada–Tapi valleys. (A) After Auden (1949). (B) and (C) after Deshmukh andSehgal (1988).



(>2000 m) mountain ranges, the Central Sahyadri andthe Southern Sahyadri.

Erosion alone cannot explain the development ofthis geomorphically spectacular and structurally peculiargap.

Considering the nature of the peculiarity of the structuraldesign and lithological complexes within the Moyar–

Bhavani–Attur Shear Zone in the north and the seismicallyactive (Rajendran and Rajendran, 1996) Palghat–CauveryShear Zone in the south (Fig.12) and the very activenature of the faults dissecting the Sahyadri and coastaldomains (Figs. 9 and 10 Upper) it has been suggested thatthe overstressed crust of the Indian shield in southernIndia broke along the reactivated reverse faults of the

Fig.5. The tracts of swarms of parallel dykes in the West Coast as well as in the Narmada–Tapi valleys, among others, are dotted with hotsprings (from Shanker, 1989).


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E–W trending Palghat–Cauvery and Moyar–Attur shearZones of Precambrian antiquity (Figs. 10 and 12). The muchfaulted southern part (Southern Granulite Terrane) was thrustup as high mountains culminating eventually in theemergence of the Nilgiri Hills in the north, and theAnnaimalai–Elaimalai Hills in the south (Valdiya, 2001b).The territory of the Palghat Gap failed to rise above 50–300 m and thus remained a low-altitude belt. The northward-directed thrust movement was transferred partially as strike-slip displacement along the reactivated N–S and NNW–SSEtrending faults of the terrains north of the Moyar–Attur Shearzone.

How else would one explain the tremendous heightsof the Southern and Central Sahyadri in the profoundlypeneplaned shield and the activeness of the fault that cutthem?

SIGNATURES OF THE MARION HOTSPOT

In the NNW–SSE trending chain of islets — the SaintMary’s Island — off the coast of northwestern Karnataka(Fig.11 upper), the eruption of the rhyolites, rhyodacites and

dacites is attributed to the Indian plate moving over theMarion Hotspot (Subbarao et al. 1993). The Ar40-Ar39 dateof the lavas is 85.6±04 Ma (Pande et al. 2001). Significantly,in the adjoining inland region of Karnataka there are90.0±1.0 and 87.5±09 Ma old dolerite dykes (Anil Kumaret al. 2001), and in northwestern Kerala the leucogabbroand felsite dykes have been dated 85 Ma (T. Radhakrishnaet al. 1999).

As the Indian plate moved over the Marion Hotspot, thelong stretch of land to the north of the St. Mary’s Islandmust have been affected, and affected considerably.

Where and what are the signatures of the MarionHotspot in the Konkan, western Gujarat and westernRajasthan?

Do the Gulf of Khambhat and its northern continuationthe Sabarmati Graben represent the impact of the Marionplume activity?

But the geophysicists say that the basement of theSabarmati Graben is made up of 1000–3200 m thick Deccanvolcanics (Tewari et al. 1995). If that is so, it cannot be thework of the Marion. It can not be related to the ReunionHotspot either.

Fig.6. Epicentres of earthquakes of moderate to low magnitude occur all along the West Coast aligned parallel to or in close proximityof the “lineaments” (after Rajendran, 2001). Inset shows focal mechanism solutions of the some of these earthquakes indicatingstrike-slip and normal faulting. (after Rastogi, 1992).



Fig.7. Major faults in the Mumbai–Bassein–Panvel region in NW Maharashtra, which have caused vertical uplift of the lava pile, andare locations of epicentres. Hot springs occur in the proximity of some faults (from Srinivasan, 2002).Upper Inset: Distribution of epicentres (�) and the faults of the Mumbai region (based on Srinivasan, 2002).Lower Inset : Abrupt deflection of rivers along the NNW–SSE trending “lineaments”, implying strike-slip displacement alongthem (based on Kundu and Matam, 2000).


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What caused the stretching and sinking of theKhambhat–Sabarmati terrane?

In the western Gujarat, the Kachchh Basin is aconsequence of lithospheric stretching and rifting (Fig.11Middle) in the late Triassic (Biswas, 1982, 2005) or mostlyin the early Jurassic. The depositional sites were of the natureof an embayment between the uplifted Tharad–Nagarparkar

Ridge in the north, and the raised Saurashtra High in thesouth and Raddhanpur–Barmer High in the east. A NNE–SSW trending feature divides the basin into two parts(Biswas and Deshpande, 1983). Then there are a couple oflong active faults trending roughly east–west. The sedimentsthat accumulated in this basin span a long period of stretchingfrom the Lower Jurassic to the Tertiary.

Fig.8. Active NNW–SSE oriented faults in the Kanara Coastal Belt and adjoining Sahyadri Range. The rivers are ponded at the pointsof their crossing these faults, implying displacement along the latter. (Valdiya, 2000b). Inset : Location of epicentres of earthquakes(�) of magnitude 3 to 5 on or in the close proximity of the “lineaments” in the above-mentioned terrains. (Based on Sambandamet al. 1994).



North of the Sabarmati Graben, the Sanchor–Barmergraben in western Rajasthan is a N–S trending narrowfault-delimited depression. The Barmer Graben (Fig.11lower) comprises sediments of the Lower CretaceousSarnu Formation unconformably overlain by the PalaeoceneFatehganj Formation (Sisodia and Singh, 2000). Thesediments span a time period of 135 to 95 m.y.

It is worthwhile noting that beyond the BarmerBasin is the Jaisalmer Basin, where petroleum has beenfound.

Are the Kachchh Basin and the Barmer Basin aconsequence of the Marion plume hitting the Gujarat–Rajasthan part of the Indian plate earlier than in St. Mary’sbelt?

If so, is there any evidence of volcanic or intrusiveactivities in the Kachchh and Barmer Grabens?

Rifting is evident, development of fault is proven.Why did not these faults provide pathways to lavas,

and sites of emplacement of magmatic intrusions?Have we missed them?What is the specific condition of heat-flow along the

margins of these basins?What does gravity studies tell about the geophysical

characteristics of the graben boundaries?

THE “SUTURES”

Within the Indian shield a number of belts and chains of

Fig.9. In the Malabar Coastal Belt and Southern Sahyadri the prominent trends of faults (“lineaments”) are WNW–ESE andNNW–SSE. The epicentres of earthquakes are located on or close to these faults (“lineaments”) (based on Rajendran and Rajendran,1997; Singh and Mathai, 2004). Inset : Locations of earthquakes in the duration December 12, 2000 to January 7, 2001 in theIrattupetta area in relation to the NNW–SSE and ENE–WSW trending faults (after Bhattacharya and Dattatrayam, 2002).


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ultrabasic–basic rocks involved in severe shearing andattendant high-grade metamorphism have been describedas “suture zones”.

The suture zones are taken to represent tectonic junctionsof collided continents or continental blocks.

In Southern Peninsular India, the Palghat–Cauvery ShearZone is a great tectonic junction or divide (Fig.12). In theeastern Namakkal area, in contrast to the complexmetamorphism under high temperature (730°C) and pressure(~ 8.5 kbar) in the belt south of the shear zone, the rocks ofthe northern block recorded metamorphism that took placeunder temperature higher than 850°C and pressure more than9.6 kbar, followed by isothermal decompression, implyingthat the shear zone represents juxtaposition of two contrasteddomains (John et al. 2005). The aeromagnetic data andanomalies of the 36 to 40 km thick Dharwar Block give

way to the E–W oriented anomaly in the nearly 22 km thickPalghat–Cauvery Shear Zone (Rajaram and Harikumar,2001) and the composite airborne total intensity map plusgravity anomaly modelling with seismic constraints suggestthat the crustal block of the Southern Granulite Terrane southof the Palghat–Cauvery Shear Zone (P-CSZ) is 44 to 46 kmthick (Mishra and Vijaya Kumar, 2005), that it shows threetimes higher heat flow (M.L. Gupta et al. 1991), and thatthere is mild to low seismicity in the Palghat–Cauvery ShearZone (Rajendran and Rajendran, 1996).

The defining faults of the Shear Zones show undoubteddip-slip movements as well as strike-slip displacement(Drury et al. 1984; Naha and Srinivasan, 1996; D’Cruz etal. 2000).

What exactly is the nature of the Palghat–CauveryShear Zone? Is it really a suture zone?

Fig.10. Upper: The much faulted terrane of southern India. The movement along many of these faults have generated earthquakes (fromValdiya, 2010).Lower: The northward directed pressure on the Indian crust caused its breaking and squeezing up of the faulted blocks. This hasresulted in the emergence of such high mountains as the Nilgiri and the Annaimalai. The block between the two high mountainsfailed to rise up and gave rise to the Palghat Gap (after Valdiya, 1998).



Fig.11. Upper: Marion Hotspot is believed to be responsible for the volcanic activity in the St. Mary’s Island, offshore NW Karnataka,and for intrusive activity in western Karnataka and northwestern Kerala (after Anil Kumar et al. 2001).Middle : The much-faulted Kachchh Basin, now comprising an E–W oriented series of ridges and half-grabens, is a consequenceof rifting of the northwestern continental margin of India (after Biswas, 2005).Lower: The Barmer Basin in Western Rajasthan is a graben in which Mesozoic–Cenozoic sediments were deposited. No signsof volcanic or magmatic activities are seen in the basin (after Sisodia and Singh, 2000).


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Or does it represents a graben of great antiquity thathas been subjected to compression during and/or after thePan-African upheaval?

If it is a suture zone between two convergent continents,where are the metamorphosed remnants of the typicalassemblages of the subduction–obduction zone, such as(i) oceanic trench sediments including turbidites and chertbeds (which make the accretionary prisms), (ii) the piecesof oceanic crust with sheeted dykes and the slices of uppermantle — that is, the ophiolite and ophiolitic melange,(iii) remains of island arc, (iv) the low-temperature high-pressure blueschists with such remarkable minerals asglaucophane, jadeite, lawsonite with or without phengiteor coesite?

Why is there no chain of Andean-type magmatism andvolcanism just outside the periphery of the zone?

But for the occurrence of ultrabasic and alkaline intrusiveplutons, particularly in the neighbourhood of the Moyar–Bhavani Shear Zone (Fig.12 Inset), no other unequivocalfeatures related to subduction, suture and obduction havebeen described.

Within the Dharwar Craton, the Chitradurga Schist Beltis delimited by the Chitradurga Boundary Fault (Fig.13) thatonce registered sinistral strike-slip movements(Ramakrishnan, 1993, 2003; Chadwick et al. 2007). TheChitradurga Boundary Fault divides the craton into theEastern and Western Dharwar Blocks. Aeromagneticanomalies and teleseismic receiver-function modelling showthat in contrast to the 35–40 km thick western block, theeastern block is 35 km thick (Reddy et al. 2000; Anand andRajaram, 2002; Gupta et al. 2003).

Questions similar to those related to the Palghat–CauveryShear Zone arise when the Chitradurga Boundary Fault orShear Zone (Figs. 12 and 13) is discussed.

What exactly is the nature of the ChitradurgaBoundary Fault?

Is it a suture?A rift boundary?What and where are the features and things that show

it one way or the other?The Sileru Shear zone (Chetty, 1995), also called the

Terrane Boundary Shear Zone (Biswal et al. 2000; Biswal

Fig.12. Sketch map of southern India showing the Moyar–Bhavani–Attur Shear Zone, the Palghat–Cauvery Shear Zone, and theChitradurga Shear Zone (Boundary Fault) that delimit the various lithotectonic blocks or terranes of the Southern Indian shield.Inset: Spatial distribution of ultrabasic and alkaline complexes show their remarkable proximity to the shear zones that delimitthe cratonic blocks against the Mesoproterozoic mobile belts. (based on Ratnakar and Leelanandam, 1989; Santosh, 1989).



and Sinha, 2003) or the Eastern Ghat Boundary Fault (Croweet al. 2003), marks the western limit of the Eastern GhatMobile Belt (Fig.14). The shear zone dips steeply (50°)eastwards with its curvilinear geometry. It is characterizedamong others by ultra-high temperature (950–1040°C at8–10 kbar) metamorphism, (Dasgupta, 1995; Dasgupta andSengupta, 2002) and intrusive plutons of basic–ultrabasicrocks, carbonatite and synkinematic alkaline complexes,some of them significantly deformed (Sarkar and Paul, 1998;Leelanandam, 1989, 2005; Leelanandam et al. 2006).

It has been suggested that the Eastern Ghat Mobile Beltwas amalgamated with the Bastar and Dharwar cratons(Dobmeier and Raith, 2003; Upadhyay et al. 2006). Thereis also a view that the intrusive bodies mark the site ofintracontinental rifting, the peaks of petrotectonic eventsoccurring at 1500 Ma, 900 and 500 Ma (Sarkar and Paul,1998).

What indeed is this Sileru Shear Zone or Eastern GhatBoundary Fault?

Does it mark a junction of two different continents?Or is it an intracontinental shear zone?The Singhbhum Shear Zone, also called Copper Belt

Thrust, is a 1–5 km wide belt of metagreywacke-volcanicassemblages, and of multiplicity of fractures and thrustplanes with variable upward displacement of the northernblock. Some of the fractures and faults reach the uppermantle and thus provided pathways to outpouring lavas andemplacement of plutons (Naha, 1962; Banerji, 1962, 1969).The occurrence of bands of mylonites testify to strongthrusting (Ghosh and Sengupta, 1990).

What does the Singhbhum Shear Zone signify? A zoneof obduction?

If yes, which lithological units represent (i) theaccretionary prism related to an oceanic trench, (ii) the

Fig.13. (A) The Chitradurga Shear Zone (Boundary Fault) divides the Dharwar Craton into eastern and western blocks, the crustalthickness of which differ (based on Chadwick et al. 2003). (B) NE–SW cross section of the Dharwar Craton demonstrates therelationship of the Peninsular Gneiss, the supracrustal Dharwar Supergroup, and the “schist belts” (based on Chadwick et al.2000).


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ophiolite and ophiolitic melanges, (iii) the island-arccomplex, and (iv) the Andean-type arc of magmatism andvolcanism?

Where are the blueschists?In Rajasthan, a steep-gradient Bouguer Gravity anomaly

of 70–80 mGal extends all along the trend of the Aravalli,the conspicuous lows coinciding with the side defined by aNW-dipping 30-km deep thrust (Tewari et al. 1998). Thepresence of divergent seismic reflection fabric implies down-warping of the crust (Vijaya Rao et al. 2000; Vijaya Raoand Reddy, 2002). Interpretation of gravity and magneticdata for depth estimation by application of scaling spectralmethod shows that the mid-crustal layer has risen up andthat the upliftment is related to a 109-km wide and 25-kmthick domal structure below the Aravalli orogen (Dimri etal. 2003).

There was thickening of the crust due either to the

addition or to underplating of granite magma (Sharma, 1988,1995), or as a result of multiple thrusting and stacking ofslabs (Sinha-Roy et al. 1993).

Interestingly, the Aravalli divides the large Rajasthancraton into the eastern Bundelkhand block and the westernMewar block.

Was there rifting apart of the crust — the breakingof the Bundelkhand–Rajasthan Craton into the MewarBlock and the Bundelkhand Block as Sinha-Roysuggests?

The layered gabbro, harzburgite and serpentinizedultramafic rocks, associated with sheeted dykes, pillow lavas,hyaloclastic material (Khan et al, 2005) and the blueschist— the Phulad Ophiolite — in the proximity of greywacke-claystone assemblage in the Phulad area is described asrepresenting ophiolitic complex (Sychanthavong and Desai,1977) of the obduction zone delimited by the Rakhabdeo

Fig.14. Sketch map of the Eastern Ghat showing what has been described as the Sileru Shear Zone, Eastern Ghat Boundary Fault andTerrane Boundary Shear Zone, and juxtaposition of the Proterozoic mobile belt against the Singhbhum, Bastar and Dharwarcratons (after Biswal and Sinha, 2003). Inset: The distribution of ultrabasic and alkaline rock complexes in the Eastern GhatMobile Belt and the Southern Granulite Terrane (based on Leelanandam, 1989, 1993).



Dislocation (Sinha Roy, 1984; Sinha-Roy and Mohanty,1988). In the Phulad–Barr belt, trace-element and rare-earthgeochemistry of the basic–ultrabasic assemblage (nowexhibiting amphibolite facies metamorphism) is,significantly, characteristic of the ocean-arc basalt (Volpeand Macdougall, 1990).

Does it mean that the Rabhabdeo Dislocation Zonetogether with the Kaliguman Dislocation Zone representsa suture, defining a zone of obduction between twocontinents?

Which petrological complexes would then representan island arc and an Andean-type magmatic-volcanicarc?

Or is it just an intracontinental rift zone complex?

Why no detailed studies have been carried out on theblueschists?

FINALLY

Plodding as I do, but continuing to sing my songs in theevening of my life, I must confess that I should have strivenmyself to address at least some of the problems whichconfronted me when I had physical energy and the companyof daring young colleagues by my side. Hopeful that thevastly more knowledgeable and physically and materiallyvery much stronger earth scientists of the present wouldbe enthused to follow the “road less travelled by”, I haveposed the questions that have stirred me greatly.

Fig.15. Sketch map of the Singhbhum Craton in juxtaposition with the Singhbhum Mobile Belt in Jharkhand. The Singhbhum ShearZone defines the boundary of the craton against the mobile belt (after Saha, 1994). IOG = Iron Ore Group; SG = SinghbhumGranite; OM = Older Metamorphics; CGC = Chhotanagpur Gneissic Complex.


316 K. S. VALDIYA

Fig.16. Sketch map of the Aravalli Mobile Belt (showing occurrence of mineral deposits), major “dislocations” and the RakhadeoSuture. (after Deb and Sarkar, 1990). Inset : Diagramatic map showing the major “dislocations” (or thrusts) in the Mewar blockof the Bundelkhand (Rajasthan) craton. (after Sinha-Roy et al. 1995).Abbreviations: A - Ambaji; AK - Akwali; B - Banera; BG - Basantgarh; BL - Balda; BM - Barolmagra; BT - Bethumni;BY - Birantia; C = Chandmari; D - Degana; DP - Devpura; DR - Devi; G - Golla; Gn - Gogunda; JP - Jahazpur; JS - Jhamarkotra;K - Kulihan; PL - Pipela; KD - Khoda-Dariba; MB - Mochiamagra-Balaria; MK - Madankudan; P - Pur; PP - Phalwad-Positara;S - Sawar; SD - Satkul-Dhanaole; SK - Sindeswar-Kalan; T - Tiranga; Up - Udaipur; Us - Umra-Udaisagar.



References

Bastar Craton in Bolangir and Kalahandi districts of Orissa.Jour. Geol. Soc. India, v.55, pp.367-380.

BISWAL, T.K. and SINHA, S. (2003) Deformation history of the NWsalient of the Eastern Ghats Mobile Belt, India. Jour. AsianEarth Sci., v.22, pp.157-169.

BISWAS, S.K. (1982) Rift basins in western margin of India andtheir hydrocarbon prospect, with special reference to Kutch,Bull. Amer. Assoc. Petrol. Geol., v.66, pp.1497-1513.

BISWAS, S.K. (2005) A review of structure and tectonics of Kutchbasin, western India, with special reference to earthquakes.Curr. Sci., v.88, pp.1592-1600.

BISWAS, S.K. and DESHPANDE, S.V. (1983) Geology and hydrocarbonprospects of Kutch, Saurashtra and Narmada basin, In: L.L.Bhandari et al. (Eds.) Petroliferous Basins of India, KDMInstitute of Petroleum Exploration, Dehradun, pp.111-126.

CHADWICK, B., VASUDEV, V.N. and HEGDE, G.V. (2000) The DharwarCraton, southern India, interpreted as a result of Late Archaeanoblique convergence. Precambrian Res., v.99, pp.91-111.

CHADWICK, B., VASUDEV, V.N. and HEGDE, G.V. (2003) TheChitradurga Schist Belt and its adjacent plutonic rocks, NWof Tungabhadra, Karnataka: A duplex in the Late Archaeanconvergent setting of the Dharwar Craton. Jour. Geol. Soc.India, v.61, pp.645–663.

CHADWICK, B., VASUDEV, V.N., HEGDE, G.V. and NUTMAN, A.P.(2007) Structure and SHRIMP U/Pb zircon ages of granitesadjacent to the Chitradurga schist belt: Implications forNeoarchaean convergence in the Dharwar Craton, southernIndia. Jour. Geol. Soc. India, v.69, pp.5-24.

CHANDRASEKHARAM, D. (1985) Structure and evolution of thewestern continental margin of India deduced from gravity,seismic, geomagnetic and geochronological studies. Physics,Earth Planet. Interiors, v.41, pp.186-198.

CHETTY, T.R.K. (1995) A correlation of Proterozoic shear zonesbetween Eastern Ghats, India and Enderby Land, EastAntarctica on Landsat imagery. Mem. Geol. Soc. India, no.34,pp.205-220.

CROWE, W.A., NASH, C.R. HARRIS, L.B., LEEMING, P.M. and RANKIN,L.R. (2003) The geology of the Rengali province: Implicationsfor tectonic development of northern Orissa, India. Jour. AsianEarth Sci., v.21, pp.697-710.

DASGUPTA, SOMNATH (1995) Pressure-temperature evolutionaryhistory of the Eastern Ghat Province: Recent advancesand some thoughts. Mem. Geol. Soc. India, no.34, pp.101-110.

DASGUPTA, S. and SENGUPTA, P. (2002) Ultrahigh temperaturemetamorphis in the Eastern Ghat belt, India, Evidence fromhigh Mg-Al granulites. Proc. Indian National Sci. Acad., v.68A,pp.21-34.

DE, ANIRUDH (1981) Late Mesozoic–Lower Tertiary magma typesof Kutch and Saurashtra. Mem. Geol. Soc. India, no.3, pp.327-339.

DEB, MIHIR and SARKAR, S.C. (1990) Proterozoic tectonic evolutionand metallogenesis in the Aravalli–Delhi orogenic complex,northwestern India, Precambrian Res., v.46, pp.115-137.

ACTON, G.D. (1999) Apparent polar wander of India since theCretaceous, with implications for regional tectonics and truepolar wonder. Mem. Geol. Soc. India, v.44, pp.129-125.

ANIL KUMAR, PANDE, KANCHAN, VENKATESAN, T.R. and BHASKAR

RAO, Y.J. (2001) The Karnataka late Cretaceous dykesas products of Marion Hotspot at the Madagaskar–India breakup event: Evidence from 40Ar-39Ar geochronologyand geochemistry. Geophys. Res. Lett., v.28, pp.2715-2718.

AITCHISON, J.C., DAVIS, A.M., BADENGZHU and LUO, H. (2002) Newconstraints on the India–Asia collision: the Lower MioceneGangrinboche conglomerates, Yarlung–Tsangpo suture zone,SE Tibet Jour. Asian Earth Sci., v.21, pp.251-263.

ALAM, MAHMOOD (1996) Subsidence of the Ganges–Brahmaputradelta of Bangladesh and associated drainage, sedimentationand salinity problems, In: J.D. Milliman and B.U. Haq (Eds.),Sea Level Rise and Coastal Subsidence. Kluwer AcademicPublishers, Amsterdam, pp.169-192.

ANAND, S.P. and RAJARAM, M. (2002) Aeromagnetic data to probethe Dharwar Craton. Curr. Sci., v.83, pp.162-167.

AUDEN, J.B. (1949) Dykes in western India — a discussion oftheir relationship with the Deccan Traps. Trans. Nat. Inst. Sci.India, v.3, pp.123-157.

BANERJEE, P. and BURGMANN, R. (2001) Convergence across thenorthwest Himalaya from GPS measurements. Geophys. Res.Lett., v.29, 10.1029/2002.

BANERJI, A.K. (1962) Cross folding, migmatization and orelocalization along part of the Singhbhum Shear Zone, southof Tatanagar, Bihar, India. Econ. Geol., v.57, pp.50-71.

BANERJI, A.K. (1969) A reinterpretation of the geological historyof Singhbhum Shear Zone, Bihar. Jour. Geol. Soc. India, v.10,pp.49–55.

BECK, R.A., BURBANK, D.W., SERCOMBE, W.J., RILEY, G.W., BARNDT,J.K., BERRY, J.R., AFZAL, J., KHAN, A.M., JURGAN, H., METJE,J., CHEEMA, A., SHAFIQUE, N.A., LAWRENCE, R.D. and KHAN

M.A. (1995) Stratigraphic evidence for an early collisionbetween northwest India and Asia. Nature, v.373, pp.55-58.

BHATIA, S.B., PRASAD, S.V.R. and RANA, R.S. (1996) Maastrichtiannon-marine ostracodes from Peninsular India: Palaeo-geographic and age implications. Mem. Geol. Soc. India,no.37, pp.297-311.

BHATIA, S.B. and RANA, R.S. (1984) Palaeogeographic implicationsof the Charophyta and Ostracoda of the intertrappean beds ofPeninsular India, Mem. Soc. Geologie France, v.147, pp.29-35.

BHATIA, S.B., RIVELINE, J. and RANA, R.S. (1990) Charophyta fromthe Deccan intertrappean bed near Rangapur, A.P., India. ThePalaeobotanist, v.37, pp.316-323.

BHATTACHARYA, S.N. and DATTATRAYAM, R.S. (2002) Earthquakesequence in Kerala during December 2000 and January 2001.Curr. Sci., v.82, pp.1275–1278.

BISWAL, T.K., JENA, S.K., DATTA, S., DAS, R. and KHAN, K. (2000)Deformation of the Terrane Boundary Shear Zone (LakhnaShear Zone) between the Eastern Ghats Mobile belt and the


318 K. S. VALDIYA

D’CRUZ, ERIC, NAIR, P.K.R. and PRASANNA KUMAR, V. (2000) PalghatGap — a dextral shear zone from the South Indian GranuliteTerrain. Gondwana Res., v.3, pp.21-31.

DESHMUKH, S.S. and SEHGAL, M.N. (1988) Mafic dyke swarms inDeccan Volcanic Province of Madhya Pradesh andMaharashtra. Mem. Geol. Soc. India, no.10, pp.323-340.

DIMRI, V.P., BANSAL, M.R., SRIVASTAVA, R.P. and VEDANTI, N. (2003)Scaling behaviour of real earth source distribution: Indian casestudies. Mem. Geol. Soc. India, no.53, pp.431-448.

DOBMEIER, C.J. and RAITH, M.M. (2003) Crustal architecture andevolution of the Eastern Ghat Granulite Belt and adjacentregions of India. Geol. Soc. London Spec. Publ., No.6, pp.145-168.

DRURY, S.A., HARRIS, N.B.W., HOLT, R.W., REEVES, S.G.J. andWIGHTMAN, R.T., (1984) Precambrian tectonics and crustalevolution in South India. Jour. Geol., v.92, pp.3-20.

GANSSER, A. (1991) Facts and theories on the Himalaya. EclogaeGeol. Helv., v. 84, pp.33-59.

GHOSH, S.K. and SENGUPTA, S. (1990) The Singhbhum Shear Zone:structural transition and kinematic model. Proc. Indian Acad.Sci. (Earth Planet. Sci.), v.98, pp.229-247.

GUPTA, M.L., SUNDAR, A. and SHARMA, S.R. (1991) Heat flow andheat generation in the Archaean Dharwar cratons andimplications for the Southern Indian Shield geotherm andlithospheric thickness. Tectonophysics, v.194, pp.107-122.

GUPTA, SANDEEP, RAI, S.S., PRAKASAM, K.S., SRINAGESH, D., CHADHA,R.K., PRIESTLEY, K. and GAUR, V.K. (2003) First evidence foranomalous thick crust beneath mid-Archaean Westen DharwarCraton. Curr. Sci., v.84, pp.1219-1225.

JADE, SRIDEVI, (2005) Estimates of plate velocity and crustaldeformation in the Indian subcontinent using GPS geodesy.Curr. Sci., v.86, pp.1443-1448.

JAEGAR, J.J., COURTILLOT, V. and TAPPONIER, P. (1989)Palaeontological view of ages of Deccan Traps, theCretaceous–Tertiary Boundary and India–Asia collision.Geology, v.17, pp.316-319.

JOHN, M.M., BALAKRISHAN, S. and BHADRA B.K. (2005) Contrastingmetamorphism across Cauvery Shear Zone, South India. Jour.Earth Sys. Sci, v.114, pp.143-158.

KHAN, M.S., SMITH, T.E., RAZA, M. and HUANG, J. (2005) Geologyand geochemistry and tectonic significance of mafic–ultramaficrocks of Mesoproterozoic Phulad Ophilite Suture of SouthDelhi Fold Belt, NW India. Gondwana Res., v.8, pp.553-566.

KLOOTWIJK, C.T., GEE, J.S. PIERCE, J.W., SMITH, F.M. andMCFADDAN, P.L., (1992) An early India–Asia contact:Palaeomagnetic constraint from Ninety-east Ridge, ODG Leg121, Geology, v.20, pp.395-398.

KUNDU, BISWAKETAN and MATAN, A. (2000) Identification ofprobable faults in the vicinity of Harnai–Ratnagiri region ofthe Konkan Coast, Maharashtra. Curr. Sci., v.78, pp.1556-1560.

LAVE, J. and AVUAC, J.P. (2000) Active folding of fluvial terracesacross the Siwalik Hills, Himalayas of central Nepal. Jour.Geophys. Res., v.105, pp.5735-5770.

LAVE, J., YULE, D., SAPKOTA, S., BASANT, K., MADDAN, C., ATTAL,

M. and PANDEY, M.R. (2005) Evidence for a great medievalearthquake (~1100 A.D.) in the central Himalaya, Nepal.Science, v.307, pp.1302-1305.

LEELANANDAM, C. (1989) The Prakasm Alkaline Province in AndhraPradesh, India. Jour. Geol. Soc. India, v.34, pp.25-45.

LEELANANDAM, C. (1993) Eulitic and ferrosilitic orthopyroxenesfrom ferosyenitic rocks of South India: Evidence for hightemperature crystallization and tholeiitic parentage. Curr. Sci.,v.64, pp.729-735.

LEELANANDAM, C., BURKE, K., ASHWAL, L.D. and WEB, S.J. (2006)Proterozoic mountain building in Peninsular India: An analysisbased primarily on alkaline rock distribution. Geol. Mag.,v.143, pp.195-212.

MALIK, J.N. and MATHEW, G. (2005) Evidence of palaeoearthquakesfrom trench investigations across Pinjore Garden fault inPinjore Dun, NW Himalaya. Jour. Earth System Sci., v.114,pp.387–400.

MISHRA, D.C. and VIJAYA KUMAR (2005) Evidence for Proterozoiccollision from airborne magnetic and gravity studies inSouthern Granulite Terrain India, and signatures of recenttectonic activity in the Palghat Gap. Gondwana Res., v.8,pp.43-54.

MOHAN, G., SURVE, G. and TIWARI, P.K. (2007) Seismic evidencesof faulting beneath the Panvel flexure. Curr. Sci., v.93, pp.991-996.

MORGAN, J.P. and MCINTYRE, W.G. (1959) Quaternary geology ofthe Bengal basin, East Pakisthan and India. Geol. Soc. Amer.,Bull., v.70, pp.319-342.

NAHA, K. (1962) Precambrian sedimentation around Ghatshila ineast Singhbhum, eastern India. Proc. Nat. Inst. Sci. India,v.27A, pp.261-272.

NAHA, K. and SRINIVASAN, R. (1996) Nature of the Moyar andBhavani Shear Zones with a note on its implications on thetectonics of the Southern Indian Precambrian shield. Proc.Indian Acad. Sci. (Earth Planet. Sci.), v.105, pp.173-189.

PANDE, KANCHAN (2002) Age and duration of the Deccan Traps,India: A review of radiometric and palaeomagnetic constraints.Proc. Indian Acad. Sci. (Earth Planet. Sci.), v.11, pp.115-123.

PANDE, KANCHAN, SHETH, H.C. and BHUTANI, R. (2001) 40AR-39Arage of the St. Mary’s Islands volcanics, Southern India: Recordof India–Madagascar break-up on the Indian subcontinent,Earth Planet. Sci. Lett., v.193, pp.39-46.

RADHAKRISHNA, T., MALUSKI, H., MITCHELL, J.G. and JOSEPH, M.(1999) 40Ar-39Ar and K-Ar geochronology of the dykes fromthe south Indian granulite terrain, Tectonophysics, v.304,pp.109-129.

RAGHU KANTH, S.T.G. and IYENGAR, R.N. (2006) Seismic hazardestimation for Mumbai city. Curr. Sci., v.91, pp.1486-1494.

RAJARAM, MITA and HARIKUMAR, P. (2001) Source field of theaeromagnetic anomalies over Peninsular India, DCS–DSTNews, January issue 16, Department of Science & Technology,New Delhi.

RAJENDRAN, C.P. (2001) Using geological data for earthquakestudies — A perspective from Peninsular India. Curr. Sci.,v.79, pp.1251-1258.



RAJENDRAN, C.P. and RAJENDRAN, KUSALA (1996) Low–moderateseismicity in the vicinity of Palghat Gap, south India and itsimplications. Curr. Sci., v.70, pp.304-307.

RAJENDRAN, C.P. and RAJENDRAN, KUSALA (1997) Seismogenicpotential of West Coast of India: Need for reassessment, Proc.Second Indian National Conf. on Harbour and OceanEngineering, CESS, Trivandrum, pp.305-314.

RAMAKRISHNAN, M. (1993) Tectonic evolution of the granuliteterrains of southern India, Mem. Geol. Soc. India, no.25,pp.35-44.

RAMAKRISHNAN, M. (2003) Craton-mobile belt relations in SouthernGranulite Terrain. Mem. Geol. Soc. India, no.50, pp.1-24.

RANGA RAO, A., (1971) New mammals from Murree (Kalakot zone)of the Himalayan foothills near Kalakot, J&K State. Jour. Geol.Soc. India, v.12, pp.125-134.

RASTOGI, B.K. (1992) Seismotectonics inferred from earthquakesand earthquake sequences in India during the 1980s, Curr.Sci., v.62, pp.101-108.

RASTOGI, B.K. (2001) Erattupetta earthquake of 12 December 2000and seismicity of Kerala. Jour. Geol. Soc. India, v.57, pp.273-275.

RATNAKAR, J. and LEELANANDAM, C. (1989) Petrology of alkalineplutons from the eastern and southern Peninsular India. Mem.Geol. Soc. India, no.15, pp.145-176.

REDDY, P.R., CHANDRAKALA, K. and SRIDHAR, A.R. (2000) Crustalvelocity structure of the Dharwar Craton, India. Jour. Geol.Soc. India, v.55, pp.381–386.

SAHA A.K. (1994) Crustal Evolution of Singhbhum, North Orissa,Eastern India. Geol. Soc. India, Bangalore, 341p.

SAHNI, ASHOK (1984) Cretaceous–Palaeocene terrestrial faunas ofIndia: Lack of endemism during drifting of Indian plate.Science, v.226, pp.441-443.

SAHNI, ASHOK and BAJPAI, S. (1991) Eurasiatic elements in theUpper Cretaceous nonmarine biotas of Peninsular India.Cretaceous Res., v.12, pp.177-183.

SAHNI, ASHOK and KUMAR, K. (1974) Palaeogene palaeo-biogeography of the Indian subcondtinent. Palaeogeogr.Palaeoclimat. Palaeoecol., v.15, pp.209-226.

SAMBANDAM, S.T., DEVAPRASAD, C., SRINIVASAN, R. and RAGHU-NANDAN, K.R. (1994) Seismotectonic Map (Scale 1 cm=20 km),Project Vasundhara, Geol. Surv. India, Bangalore, 73p.

SANTOSH, M. (1989) Alkaline plutons, decompression granulitesand Late Proterozoic CO2 influx in Kerala, South India. Mem.Geol. Soc. India, no.15, pp.177-188.

SARKAR, A. and PAUL, D.K., (1998) Geochronology of EasternGhats mobile belt – A review. Geol. Surv. India Spec. Publ.,v.44, pp.51-86.

SENTHIL KUMAR, WESNOUSKY, S.G., ROCKWELL, T.K., BRIGGS, R.W.,THAKUR, V.C. and JAYANGONDAPERUMAL, R. (2006)Palaeoseismic evidence of great surface rupture earthquakesalong the Indian Himalaya. Jour. Geophys. Res., v.111, doi10.1029.

SHANKER, RAVI, (1989) Heat flow map of India and discussion onits geological and economic significance. Indian Minerals,v.42(2), pp.89-110.

SHARMA, R.S. (1988) Pattern of metamorphism in the Precambrianrocks of the Aravalli mountain belt. Mem. Geol. Soc. India,no.7, pp.33-76.

SHARMA, R.S. (1995) An evolutionary model for Precambrian crustof Rajasthan: Some petrological and geochronologicalconsiderations. Mem. Geol. Soc. India, no.31, pp.91-115.

SHETH, HETU, C. (1999) Flood basalts and large igneous provincesfrom deep mantle plumes: Fact, fiction and fallacy.Tectonophysics, v.311, pp.1-29.

SINGH, H.N. and MATHAI, J. (2004) Field investigations forcollecting microseismic geological data on grounddeformations, CESS-PR Tech. Report, 13, 2004, Centre forEarth Science Studies, Trivandrum, 96p.

SINHA, RAJIV and JAIN, K. (1998) Flood hazards of north Biharrivers, Indo-Gangetic Plains. Mem. Geol. Soc. India, no.41,pp.27–52.

SINHA-ROY, S. (1984) Precambrian crustal interaction in Rajasthan,NW India. Indian Jour. Earth Sci., CISM Volume, pp.84-91.

SINHA-ROY, S., MALHOTRA, G. and GUHA, D.B. (1995) A transectacross Rajasthan Precambrian terrain in relation to geology,tectonics and crustal evolution of south-central Rajasthan.Mem. Geol. Soc. India, no.31, pp.63-90.

SINHA-ROY, S. and MOHANTY, M. (1988) Blue schist faciesmetamorphism in the ophiolitic mélange of the LateProterozoic Delhi Fold Belt, Rajasthan. Precambrian Res.,v.42, pp.97-105.

SINHA-ROY, S., MOHANTY, M. and GUHA, D.B. (1993) Banasdislocation zone in Nathadwara–Khannor area, Udaipurdistrict, Rajasthan and its significance on the basement-coverrelations in the Aravalli fold belt. Curr. Sci., v.65, pp.68-72.

SISODIA, M.S. and SINGH, U.K. (2000) Depositional environmentand hydrocarbon prospects of the Barmer Basin, Rajasthan.NAFTA, v.9, pp.309-326.

SRINIVASAN, V. (2002) Post-Deccan Trap faulting in Raigad andThane districts of Maharashtra. Jour. Geol. Soc. India, v.59,pp.23-31.

SUBBARAO, K.V., VALSANGKAR, A.B. and VISHWANATHAN, S. (1993)Mineralogy of the acid volcanics of St. Mary’s Islands. Proc.Nat. Acad. Sci. India, v.63A, pp.97-113.

SUKHIJA, B.S., RAO, M.N., REDDY, D.V., NAGABHUSHANAM, P.,KUMAR, D., LAKSHMI, B.V. and SHARMA, P. (2002)Palaeoliquifaction evidence of prehistoric large/greatearthquakes in North Bihar, India. Curr. Sci., v.83, pp.1019-1025.

SYCHANTHAVONG, S.P. and DESAI, S.D. (1977) Protoplate tectonicscontrolling the Precambrian deformation and metallogenicepochs in northwestern India. Mineral Sci. Engg., v.9, pp.218-236.

TEWARI, H.C., DIXIT, M.M. and SARKAR, D. (1995) Relationship ofthe Cambay rift basin to the Deccan volcanism. Jour.Geodynamics, v.20, pp.85-95.

TEWARI, H.C., DIVAKARA RAO, V., NARAYANA, B.L., DIXIT, M.M.,MADHAVA RAO, N., MURTY, A.S.W., RAJENDRA PRASAD, B.,REDDY, P.R., VENKATESWARULU, N., VIJAYA RAO, V., MISHRA,D.C. and GUPTA, S.C. (1998) Nagaur–Jhalawar geotransect


320 K. S. VALDIYA

across the Delhi–Aravalli Fold Belt in northwest India. Jour.Geol. Soc. India, v. 52, pp.153-161.

TEWARI, H.C., VIJAYA RAO, DIXIT, M.M., RAJENDRA PRASAD, B.,MADHAVA RAO, N., VENKATESWARLU, N., KHARE, P., KESAVA RAO,G., RAJU, S. and KAILA, K.L. (1995) Deep crustal reflectionstudies across the Delhi–Aravalli fold belt: results from thenorthwestern part. Mem. Geol. Soc. India, no.31, pp.383-402.

UPADHYAY, D., RAITH, M.M., MEZGER, K., BHATTACHARYA, A. andKINNY, P.D. (2006) Mesoproterozoic rifting and Pan-Africancontinental collision in SE India: Evidence from the Khariaralkaline complex. Contrib. Mineral. Petrol., v.151, pp.434-456.

VALDIYA, K.S. (1998) Late Quaternary movement and landscaperejuvenation in southeastern Karnataka and adjoining TamilNadu and Southern Indian Shield. Jour. Geol. Soc. India, v.51,pp.139-166.

VALDIYA, K.S. (2001a) River response to continuing movementsand scarp development in central Sahyadri and adjoiningcoastal belt. Jour. Geol. Soc. India, v.57, pp.13-30.

VALDIYA, K.S. (2001b) Tectonic resurgence of the Mysore Plateauand surrounding regions in cratonic southern India. Curr. Sci.,v.81, pp.1068-1089.

VALDIYA, K.S. (2010) The Making of India: GeodynamicEvolution. Macmillan, New Delhi, 816p.

VALDIYA, K.S. and NARAYANA, A.C. (2007) River response to

neotectonic activity: Example from Kerala, India. Jour. Geol.Soc. India, v.70, pp.427-443.

VIJAYA RAO, V., RAJENDRA PRASAD, B., REDDY, P.R. and TEWARI,H.C. (2000) Evolution of Proterozoic Aravalli–Delhi Fold Beltin the northwestern Indian Shield from seismic studies.Tectonophysics, v.327, pp.109-130.

VIJAYA RAO, V. and REDDY, P.R. (2002) A Mesoproterozoicsupercontinent: Evidence from the Indian Shield. GondwanaRes., v.5, pp.63-74.

VOLPE, A.M. and MACDOUGALL, J.P. (1990) Geochemistry andisotopic characteristics of mafic (Phulad Ophiolite) and relatedrocks in the Delhi Supergroup, Rajasthan, India: implicationfor rifting in the Proterozoic. Precambrian Res., v.48, pp.167-191.

WESNOUSKY, S.G., KUMAR, S., MOHINDRA, R. and THAKUR, V.C.(1999) Uplift and convergence along the Himalayan FrontalThrust. Tectonics, v.18, pp.967-976.

XIAOYING, SHI, JIARUM, Y. and CAIPING, J. (1996) Mesozoic toCenozoic sequence: stratigraphy and sea level changes in thenorthern Himalayas, southern Tibet, Newsl. Stratigr., v.33,pp.15-61.

ZAMAN, HAIDER, YOSHIDA, M., KHADIM, I.M., AHMAD, M.N. andAKRAM, H. (1999) Palaeomagnetism of the Himalaya–Karakoram belt and surrounding terranes since the Jurassic:Implications for three-phase collision. Mem. Geol. Soc. India,no.44, pp.177-207.

(Received: 31 January 2011; Revised form accepted: 5 April 2011)

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