Proterozoic Sedimentary Basins

8/10/2019 Proterozoic Sedimentary Basins

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Proterozoic Sedimentary Basins

Vindhyan BasinCuddapah Basin

Kurnool Group


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INTRODUCTION A number of nearly flat-lying,

virtually unmetamorphosed andpartly deformed proterozoiccratonic basins forms a significantpart of the Precambrian shield ofIndia.

These basins predominantly

contain orthoquartzite, shale,carbonate suites varying inthickness form 100 to 10,000 mand deposited episodically, withfrequent breaks in sedimentation,over a time span of about 1000

Ma. These are called as Puranabasins in Indian Stratigraphy(Holland, 1907), like the Ripheanof Russia with which these basinshave often been comparedbecause of their great similarities.


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INTRODUCTION The profound

unconformity betweencrystalline basementand the Purana basins,seen in the field as asharp, erosional, angularunconformity or non-conformity, markedinvariably by basalconglomerate, wascalled in early literature

the Great Eparchaean

Unconformity.


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Recent advances in the Precambrian Geology have renderedsuch terminology as Eparchaean Unconformity and Purana

basins obsolete in the global context are:

Main reasons:i) The international sub-commission on

Precambrian stratigraphy has fixed the Archaean-Proterozoic boundary as ageochronological datum at 2500 Ma without reference to any particularstratotype.

ii) The crystalline basement in india is notnecessarily Archaean everywhere, as

seen in some proterozoic supracrustalbelts unconformably underlying thesubhorizontal basins (eg. Kotri-Dongargarh belt underlyingChhattisgarh basin).


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Purana basins are mainlyintra-continental basins,

described commonly ascratonic or epicratonicbasins.

They are mostly situatedclose to the periphery ofcratons; some may belocated in the cratonicinterior (intra-cratonic basin-Kaladgi, Bhima), and rarelybetween cratons (inter-cratonic Godavari basin lying betweenDharwar and Baster cratons).


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They are also describedas platform basins (Sleep etal., 1980).

Their study is useful forglobal comparison withsimilar basin in Canada,

Australia and Africa thatwill help to understandthe Earths Proterozoiccrustal development andthe land-sea interactionsduring that period.


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Proterozoic sedimentary basinsPalaeoproterozoic Basins

Bijawar and Sonraibasins and HardaInlier - BundelkhandCraton

Gwalior basin -Bundelkhand Craton

Abujhmar basin -Bastar Craton

Papaghni sub-basin.(Cuddapah Basin) -Dharwar Craton


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Proterozoic sedimentary basinsMeso-Neoproterozoic Basins1. Vindhyan basin. -

Bundelkhand Craton2. Chhattisgarh basin - Bastar

Craton3. Khariar basin - Bastar Craton4. Ampani basin - Bastar Craton

5. Keskal, Singanpur andChedrapal outliers - BastarCraton

6. Indravati basin - Bastar Craton7. Sabari (Sukma) basin - Bastar

Craton

8. Pranhita-Godavari basin Baster Craton9. Cuddapah basin - Dharwar

craton10. Kaladgi basin - Dharwar craton11. Bhima basin - Dharwar craton


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Vindhyan Basin


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Vindhyan Basin

The largest single Puranabasin in the IndianPeninsular Shield is thespectacular, sickleshaped, ENE trending

Vindhyan Basin, situatedon the Bundlekhandcraton.

Covers on exposed areaof 60,000 sq.km and aconcealed area of1,62,000 sq.km under theIndo-Gangetic Alluviumand Deccan Trap.


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The Son-Narmada fault bounds the basin in thesouth and the Great Boundary fault in thenorthwest.

Geographically, extends from Sasarm in the eastto Dholpur in the north, passing through the sonValley, Bhopal, Dhar Forest and Chittorgarh and

Sawai Madhopur areas. The long history of studies on the VB

commencing from the work of D.H. Williams in1848.

The main classification up to Group levelproposed by the early pioneers and recently thisgroup is considered as Supergroup .


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T. Oldham (1856) proposed 3 fold division intoKaimur, Rewa and Bhander.

H.B. Medlicott (1859) introduced the term Semrifor the sediments underlying the Kaimur.

F.R. Mallet (1969) designated the Semri asLower Vindhyan, - as distinct from the rest asUpper Vindhyan, and this was in vogue untilrecently (Srivastava et al., 1983).

Among the stratigraphic Schemes Currently in

use are those of Sastry and Moitra (1984) andSoni et al. (1987), which was adopted by Kaleand Phansalkar (1991).


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Among the Sedimentological contribution- bySingh (1980), Valdiya et al . (1982) andBhattacharya (1996).

Others Zutshi and Panwar (1997), Petroleum Asia Journal (1983) and Valdiya et al. (1982).

The Vindhyan basin displays a wide variety ofdepositional environments in space and time that

have been studied by many workers beginningwith Auden (1933).


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Lithostratigraphy of Vindhyan SupergroupGroup Formation Alternative names

BhandarGroup(1300-1500 m)

Maihar SandstoneSirbu ShaleBundi Hill SandstoneGanurgarh Shale---------------------------Disconformity

(Upper Bhandar Sst., Divided into Bhavpur Sh. Balwan Lst. Shikaoda Sst)

/ Gradational Contact--------------------------------------------------------------------------

Rewa Group(100-300 m)

Govindgarh SandstoneDrummondganj SandstoneJhiri ShaleAsan SandstonePanna Shale------------------------Normal Contact

(Upper Rewa Sandstone., Gahadra Sandstone.)

(Variegated Shale)(Lower Rewa Sandstone., Itwa Sandstone., Kanar Sandstone.)

/ Facies Change----------------------------------------------------------------------------------

Kaimur Group(400 m)

Dhandraul QuartziteMangesar FormationBijaigarh ShaleMarkundi SandstoneGhurma ShaleSasaram Sandstone--------------------------- Unconformity

(Upper Kaimur Sanstone. Scarp Sandstone.)

(Ghaghar Sandstone)(Susnai Breccia)(Lower Kaimur Sandstone)/Normal Contact-----------------------------------------------------------------------------------

Semri Group(3000-4000 m)

Suket Shale

Rohtas LimestoneChorhat SandstoneBargawan LimestoneKheinjua ShaleChopan PorcellaniteKajrahat LimestoneArangi ShaleDeoland Sandstone-------------- Angular Unconformity

(Baghwar shale)

(Nimbahera Lst., Divided into Bari Sh., Jiran Sst. and Khori Malan Cong.(Gluconite Bed, Rampur Sst., Basuhari Sst, Tiohan Breccia)(Salkhan Lst., Fawn Lst., Chorhat Lst., Tirohan Lst.)(Olivine sh., Koldaha sh., Binota Sh.,)(Deonar Proc.)(Kuteshwar Lst., Bhagwanpura Lst., Tirohan Lst., Lohar Dol.)

(Khardeola Sst., Pandwafall Sst.)/ Non-conformity-----------------------------------------------------------------------------------

Granites and Supercrustals


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Description of Lithology- Semri Group

Its names from Semri River near Bijawar and is welldeveloped in the eastern Son valley near Sidhi andaround Chittorgarh, and some extent near Bijawarand Sawai Madhopur.

Its thickness near Sidhi is 3430m, whereas

elsewhere estimates vary from 20 to 4345m. Generally, the sediments tend to thin to the west

and north, and the variable thickness indicates anirregular basin floor.

Semeri Group rests with non-conformity onBundelkhand and Berach granites as well asBanded Gneissic Complex (BGC), and with angular

unconformity on Bijawar Group.


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Description of Lithology- Semri Group

The basal succession consists of Conglomerate,cross-bedded ferruginous sandstone and shale,exposed mainly in Rajasthan (Khardeola Sst.) InBundelkhanda and Son Valley, the basal unitconsists of Sst. (Deoland or Pandwafall Sst.),overlain by shale (Arangi shale).

The sandstone is glauconitic with lenses of chertand limestone suggesting transgressive marineenvironment.

The overlying stromatolitic limestone and dolomite(Kajrahat) containing illite and kaolinite suggest acontinental shelf setting.

Presence of native sulphur and pyrite in black shaleindicates volcanic, euxenic environment.


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The associated Conophyton bearing limestone,lime-chert conglomerate and turbidite suggest deep-water slope to basinal environment.

The overlying oliven Shale (kheinjua Shale), FawnLimestone (Bargawan Limestone) and glauconitesiltstone (Chorhat Sandstone) suggest a compositeenvironment.

Similar environments were visualised for RohtasLimestone and Suket Shale but other workerssuggest a lagoonal environment instead.

Semri Group(3000-4000 m)

Suket Shale

Rohtas LimestoneChorhat SandstoneBargawan LimestoneKheinjua ShaleChopan PorcellaniteKajrahat LimestoneArangi ShaleDeoland Sandstone-------------- Angular Unconformity

(Baghwar shale)

(Nimbahera Lst., Divided into Bari Sh., Jiran Sst. and Khori Malan Cong.(Gluconite Bed, Rampur Sst., Basuhari Sst, Tiohan Breccia)(Salkhan Lst., Fawn Lst., Chorhat Lst., Tirohan Lst.)(Olivine sh., Koldaha sh., Binota Sh.,)(Deonar Proc.)(Kuteshwar Lst., Bhagwanpura Lst., Tirohan Lst., Lohar Dol.)

(Khardeola Sst., Pandwafall Sst.)/ Non-conformity-----------------------------------------------------------------------------------

Granites and Supercrustals


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Description of Lithology- Kaimur Group

The Kaimur Scarp, has conformable contact with

Semri Group in son valley and Chittorgarh, but hasangular unconformable contact at Kalinjer Fort.

The Pipartola, Bundi and Dulchipur Conglomeratesseparate both the groups in Western Bundelkhandand Rajasthan.

The presence of clasts of Semri Sst. and Sh. in theBasal congl. suggests significance time gap.

Kaimur Group(400 m)

Dhandraul QuartziteMangesar FormationBijaigarh ShaleMarkundi SandstoneGhurma ShaleSasaram Sandstone

--------------------------- Unconformity


(Ghaghar Sandstone)(Susnai Breccia)(Lower Kaimur Sandstone)

/Normal Contact-----------------------------------------------------------------------------------


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Description of Lithology- Kaimur Group

Kaimur Group is essentially a Sst-Sh. association,as against the Sh.-Lst. association of Semri Group.

The basal Sasaram Sst. overlain by Markundi Sst.and intervening silicified shale are interpreted asproduct of either high velocity coastal stream orbarrier beach dune or tidal flat.

The overlying Dhandrual qtz. consisting of arkosicsst., with associated pebble beds and shale(Mangesar Fm.), is visualised as a braideephemeral stream deposit or as sandy intertidal flator tidal channel deposits.

Kaimur Group(400 m)

Dhandraul QuartziteMangesar FormationBijaigarh ShaleMarkundi SandstoneGhurma ShaleSasaram Sandstone

--------------------------- Unconformity


(Ghaghar Sandstone)(Susnai Breccia)(Lower Kaimur Sandstone)

/Normal Contact-----------------------------------------------------------------------------------


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Description of Lithology- Rewa Group

Rewa state, is characterised by frequent lateral facieschange ad is best exposed around Satna, Shivapuri and

Chittorgarh. The sediments thicken to the north indicating deepening of

the basin. Rewa Group is also well developed in Harda Inlier near

Hoshangabad, known in earlier literature as Dhar Forestarea.

The basal Panna shal, without any basal congl., indicatescontinuity of deposition from Kaimur Group.

Red Sh.. Lst., Barytes and Gluconitic siltstone (Panna Sh. and Asan Sst.) indicate lagoonal environment.


Govindgarh SandstoneDrummondganj SandstoneJhiri ShaleAsan Sandstone

Panna Shale------------------------Normal Contact



/ Facies Change----------------------------------------------------------------------------------


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Description of Lithology- Rewa Group

The coarsening upward sandstone with mudcrackssuggests periodical exposure.

The overlying Jhiri Sh. is separated from Asan Sst.by diamondiferous congl. at Panna.

Mudcracks an rain prints in the shale indicatesubaerial conditions.

Drummondganj Sst. is deposited in shore faceenvironment. The overlying Govindgarh Sst. ispoorly sorted, pebbly and texturally immature,indicating either fluvial deltaic or near shore muddytidal flat environment.


Govindgarh SandstoneDrummondganj SandstoneJhiri ShaleAsan Sandstone

Panna Shale------------------------Normal Contact



/ Facies Change----------------------------------------------------------------------------------


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Description of Lithology- Bhander Group

Overlying Bundi hill Sst. is a fining upwardtransgressive deposit tidal flat.

Overlying Purple Sirbu Sh. with halite castsindicates oxidising to arid conditions.

The top unit of Maihar Sst. is a blanket deposit withripple marks, cross bedding and load costs,intercalated with stromatolitic limestone beds,suggesting an overall tidal flat to near shore littoralenvironment.

Tidal and aeolean depositional sequence for thisSst-Sh-Sst-stromatolitic Lst.

BhandarGroup(1300-1500 m)

Maihar SandstoneSirbu ShaleBundi Hill SandstoneGanurgarh Shale---------------------------Disconformity

(Upper Bhandar Sst., Divided into Bhavpur Sh. Balwan Lst. Shikaoda Sst)

/ Gradational Contact--------------------------------------------------------------------------


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Age

Recent robust dating has fixed the beginning ofVindhyan Sedimentation around 1600-1720 Ma

(Ray, 2006).

Kajrahat Limestone has given Pb-Pb isochron ageof 1720 Ma.

Silicified tuffs of Kheinjua Formation (Semri Group)are dated by SHRIMP U-Pb zircon method at1628+8 Ma and 1599+8 Ma.

Kimberlites of Panna yield Rb-Sr ages of 1067+31Ma, 1140+20 Ma and 1130+20 Ma, which suggestthe age of Kaimur Group tobe about 1100-1150 Ma.


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Age

Age of Rewa and Bhander Groups have not beendetermined yet, but estimated to be 1100-700 Ma;

although some parts of the Bhander Group indicatea late Neoproterozoic age (~700-600 Ma)-biotic.

The time span of over 1000 Ma between 1700 Ma

and 600 Ma was tacitly assumed by many workersto suggest uninterrupted sedimentation for such aprolonged duration, but the pattern of sedimentationpunctuated by four major unconformities markingsignificant breaks, indicates that the sedimentation

was episodic over a long period (Kale, 1991;Chaudhuri et al , 2002).


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Life in the Vindhyan Period Venkatachala et al., (1996), Kumar (2003)

and De (2006) provide summaries of life inthe Vindhyan Period.

Evidence of life is either direct (mega- andmicro-fossils) or indirect (stromatolites,trace fossils, algal mats etc).

Among the important megafossils are thevarious species of Chuaria and Twauia and their equivalent in the Semri, Rewa

and Bhander Groups. These also includecarbonaceous forms, their impressionsand pseudomorphs.

Microfossils reported from Semri andbhander Groups include a variety ofcyanobacterial, not hav any chrnologicalsignificance, except possibly a few likeObruchevella species that suggest UpperRiphean (600-950 Ma) age for the LakheriLimestone and Bundi Hill Sandstone ofBhander Group.
http://en.wikipedia.org/wiki/Ediacarian


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Life in the Vindhyan Period FIGURE 31 6, Wengania m i n u t a n. sp.; 7 ,O b r u c h e v e l l a filament within Salomehubeiensis Zhang, 1986 sheaths, 8, 9 ,Meghystrichosphaeridium chadianensis (Chenand Liu, 1986) and 10, 11 , Dicrospinasphaerazhangii (Yuan and Hofmann, 1998). 1, HUHPC-64826, thin section NTC-4-8-2,coordinates 24.7 x 127.5; 2, HUHPC-64827,thin section NTC-4-1-1, coordinates 24.7 x95.7; 3, HUHPC-64828, thin section NTC-4-5-2, coordinates 16.6 x 106; 4, HUHPC-64829,thin section NTC-4-7-4, coordinates 40.9 x 120;5, HUHPC-64830, thin section NTC-4-7-2,

coordinates 37.6 x 125; 6, holotype, HUHPC-64831, thin section NTC-4-12-1, coordinates32.2 x 110.5. 7, arrows indicate turning pointsof helical filament within multiple layeredsheaths. HUHPC-64832, thin section NTC-4-5-2, coordinates 13.1 x 125.5; 8 , 9, two views, atdifferent focus levels, of the same specimen ofM. chadianensis . Arrows point to characteristicprocesses of M. chadianensis . HUHPC-64833,

thin section NTC-4-7-5, coordinates 45.7 x133.3; 10, 11, two views, at different focuslevels, of the same specimen of D. zhangii .

Arrows point to solid, branching processescharacteristic of D. zhangii . HUHPC-64834,thin section NTC-4-7-3, coordinates 41.2 x107.7. Scale bar in 1 represent 50 m for 1 6 and 8 11 and 200 m for 7


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Cuddapah Basin


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The crescent shaped,easterly concave and N-

S trending, Cuddapahbasin covers an area of44,000 sq km in theeast-central part ofDharwar Craton.

The basin extends for alength of about 45 kmalong the arcuateeastern margin with a

mean width of 150 km,and is the secondlargest Purana basin ofPeninsular India, afterthe great Vindhyan

basin.


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Cuddapah basin is characterizedby quartzite-carbonate-shalecycles having an aggregatethickness that is estimated to varybetween 6 and 12 km. The earlysediments of the basin areinterspersed with basic volcanicsand sills, similar to the smallPaleoproterozoic basins of

Abujhmar, Bijawar and Gwalior.

Felsic volcanics and tuffs areintercalated with sediments atmany horizons.

The basin is well known for itsmineral potential in the form oflimestone and dolomites, bedded

and vein barytes, chrysotileasbestos and steatite, besidesoccurrences of base metals,diamond, phosphorite, uraniumand abundant building andornamental stones.


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The Papaghni sub-basin containing lower Cuddapahsediment and the Kurnool sub-basin containing theYounger Kurnool sediments that ovelie the Cuddapahsequence with a major unconformity.

Srisailam sub-basin contain Upper Cuddapahsediments.

Palnad sub-basin exposes only the Younger Kurnoolsequence. The eastern half of the Cuddaupah basin is occupied by

the Nallamalai ford belt consisting of Upper Cuddapah

sediments. Nallamalai fold belt is demarcated from the undeformed

western sub-basins by the prominent fault lineamentcalled the Rudravaram line along which cleavage begins

to develop in the Cuddapah sediments.


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Cuddapah Basin- Previous works 1870 by V. Ball; T. Oldham; R. Bruce Foote and W. King. The monumental work of King (1942) proposing the first stratigraphic

sequence for the basin held sway for nearly a century. Systematic mapping by GSI led to some significant changes in

Stratigraphy : Dutt (1975) the Kurnool basin. Sen and Narasimha Rao (1967) & GSI (2001c) volcanism and

Paleogeography.

SVLN Rao et al., (1964) Thyagarajan (1964) and Rajurkar andRamalingaswamy (1975) stratigraphy and sedimentation. Narayanaswami (1966a)- tectonics and NGRI (1986)-gravity studies. B.K. Nagaraja Rao and G. Ramalingaswamy (1976) proposed

classification. Periodica summaries of the geology were published from time to time by

Meijernik et al., (1984), Dutt (1986),Nagaraja Rao. et al., (1987), Hari Narain (1987)and Lakshminarayana et al .,(2001).

The stratigraphy of the basin as modified by Nagaraja Rao et al., (1987).

Lithostratigraphy of Cuddapah Basin


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t ost at g ap y o Cuddapa Bas

KurnoolGroup(200 -450 m)

Kundair Subgroup(75-150 m)

Nandyal Shale (50-100 m)Koilkuntla Limestone (15-50 m)Paniam Quartzite (10-35 m)

Shale, partly calcareousSiliceous, shaly limestone with quartzite interbeds.Massive and pinnacled qurtzite, siliceous shale, basal

pebble bed.

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

JammalamaduguSubgroup(120-260 m)

---------Paraconformity----------------

Auk Shale (19-15 m)

Narji Limestone (100 200 m)

Banganapalle Quartzite (10-50 m)

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

Laminated shale, mostly ochreous with siltstoneinterbeds.Flaggy grey limestone, glauconitic sandstone

interbeds.Oligomict conglomerate, grit quartzite, shale.

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

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

----------Unconformity----------------Srisailam Quartzite (300 m)

-----------Unconformity --------------

--------------------------------------------------------Glauconitic ferruginous quartzite with shale

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

CuddapahSupergroup

Nallamalai Group(3500- 6000 m)

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

Cumbum FormationPullampet FormationBairenkonda Quartzite (1500 m)Nagari Quartzite (4000 m)

------- Angular Unconformity--------

Mainly slate and Phyllite, Chert, dolomiteShale, felsic tuff, barytes, dolomite, quartzite.Qurtzite, Quartz wacke, shale.Qurtzite, Quartz wacke, shale basal conglomerate

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

Chitravati Group(4900-5000 m)

Gandikota Quartzite (300 m)

Tadpatri Formation (4600 m)

Pulivendla Quartzite (1-75 m)

Shale-quartzite alternations, gluconitic quartziteinterbeds.

Shale, felsic tuff, basic sills and f lows, chert,stromatolitic dolomite quartzite

Quartzite and conglomerate

Papaghni Group(2100 m)

Vempalle Formation (1900 m) withKuppalapalle volcanics.

Gulcheru Quartzite (30-210 m)

Stromatolitic dolomite, chert, quartzite, basic sills andflows.

Basal conglomerate, arkose quartzite with shaleinterbeds.

Crystalline basement of Dharwar Craton


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Cuddapah Basin- Papaghni Group Group rests with non-conformity

on the granitic basement and withprofound angular unconformity

over the greenstone belts or EDC. The unconformity is marked byprominent basal conglomerate.

Group consists of a lowerarenaceous sequence (GulcheruQuartzite) and upper carbonate

sequence topped by basicvalcanic and sills (VempalleFormation).

Gulcheru quartzite is aconglomerate -quartzite sequence.The quartz pebble conglomeratehas dominate clasts of vein quartz,along pebbles of granite, quartzite,chert, jasper and BIF. Theconglomerate is overlain by pebblyand non-pebbly quartzite,glauconitic sandstone, laminatedsiltstone and shale interlayered

with dolomite.


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Cuddapah Basin- Papaghni Group

Vempalle formation- shale,siltstone and stromatolitic dolomite

in the lower part associated withphospahtic and uraniferoushorizons.

The upper unit- shale-chert beds,chert breccia, sandstone andstromatolitic dolomite- the

lithological association suggeststidal flat to shallow marineenvironment.

Kuppam volcanics- of tholeiiticbasalt and basaltic andesite occurat the top of Vempelle Formation.Sills of picrite, gabbro and doleriteare also abundant. The flows andsills are horizontal or low dippingand are interstratified withsediments.


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C dd h B i Chi i G


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Cuddapah Basin- Chitravati Group Tadpatri Formation 10 m thick gradational contact with the underlying

Pulivendla Quartzite. Purple shale with siltstone and carbonate, and grey shale interbedded

with stromatilitic dolomite having biogenic (?) concretions, chert beds andsiltstone intercalations.

Several ridge-like sills of gabbro and dolerite are conspicuous. Pillowed spilitic lava suggestive of submarine alteration is noted at

Venkatapuram.

The presence of tidalite, as well as flaser and lenticular bedding suggeststidal flat to shallow offshore environment.

CuddapahSupergroup


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




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





Shale-quartzite alternations, gluconitic quartziteinterbeds.Shale, felsic tuff, basic sills and flows, chert,stromatolitic dolomite quartziteQuartzite and conglomerate


Vempalle Formation (1900 m) withKuppalapalle volcanics.Gulcheru Quartzite (30-210 m)

Stromatolitic dolomite, chert, quartzite, basic sillsand flows.Basal conglomerate, arkose quartzite with shaleinterbeds.


C dd h B i Chi i G


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Cuddapah Basin- Chitravati Group Gandikota Formation Gandikota Fort has a gradational contact with

Tadpatri Formation marked by shale-siltstone-sandstone alternations. The overlying thick quartzite is profusely ripple-marked and cross

laminated. Presence of glauconite, high degree of maturity, sheet geometry and

herring bone cross bedding in the quartzite suggests tide-dominatedshallow shelf sea setting.

Earlier worker correlated Nagari and Bairenkonda Quartzites with the

Gandikota Quartzite.

CuddapahSupergroup


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




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





Shale-quartzite alternations, gluconitic quartziteinterbeds.Shale, felsic tuff, basic sills and flows, chert,stromatolitic dolomite quartziteQuartzite and conglomerate


Vempalle Formation (1900 m) withKuppalapalle volcanics.Gulcheru Quartzite (30-210 m)

Stromatolitic dolomite, chert, quartzite, basic sillsand flows.Basal conglomerate, arkose quartzite with shaleinterbeds.


C dd h B i N ll l i G


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Cuddapah Basin- Nallamalai Group Nagari Quartzite thick-bedded arenite with herringbone cross bedding

and is underlain by a conglomerate. Bairenkonda Quartzite Quartzite-pelitic cycle in the lower part and a

thick nature quartz arenite in the upper part. Pelite-arenite cycles are best seen in the Iswarakuppam dome, and

arenites are exposed between Chelima and Giddalur as well as at Ahobilam, Maidukuru and Velikonda hills.

Bairenkonda and Nagari Quartzites indicate shallow marine depsitional

environment.


------------------------JammalamaduguSubgroup

-------Paraconformity---------------Auk Shale (19-15 m)Narji Limestone (100 200 m)Banganapalle Quartzite (10-50 m)

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

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

----------Unconformity----------------

Srisailam Quartzite (300 m)-----------Unconformity --------------

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

Glauconitic ferruginous quartzite with shale-----------------------------------------------------

CuddapahSupergroup


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


---- Angular Unconformity--------


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

Chitravati Group Gandikota Quartzite (300 m), Tadpatri Formation (4600 m), Pulivendla Quartzite (1-75 m)



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Cuddapah Basin- Nallamalai Group Nagari Quartzite thick-bedded arenite with herringbone cross bedding

and is underlain by a conglomerate. Bairenkonda Quartzite Quartzite-pelitic cycle in the lower part and a

thick nature quartz arenite in the upper part. Pelite-arenite cycles are best seen in the Iswarakuppam dome, and

arenites are exposed between Chelima and Giddalur as well as at Ahobilam, Maidukuru and Velikonda hills.

Bairenkonda and Nagari Quartzites indicate shallow marine depsitional

environment.




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

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

----------Unconformity----------------


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


CuddapahSupergroup


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




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




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Cuddapah Basin- Nallamalai Group Cumbum Formation Kambham village, essentially shaly sequence of

banded shale and shaly rhythmite that progresses into slate and phylliteassociation with arenite, towards eastern margin of the basin.

Chert, dolomite, olistromal dolomite and siliceous shale are locallyimportant.

The dolomite hosts a marginal lead-zinc deposit at Agnigundala andZangamrajupalle-Varikunta.

The depositional environment of Cumbum formation is probably supra-

tidal.




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

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

----------Unconformity----------------


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


CuddapahSupergroup


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




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


C ddapah Basin Nallamalai Gro p


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Cuddapah Basin- Nallamalai Group Pullampet Formation Purple shale and calcareous shale with interbeds

of dolomite and quartzite. The single largest deposit of bedded barytes in the world occurs within

Pullampet Formation at Mangampeta, where volaniclastics rich in bariterosetters and barium felspar host the deposit.

The genesis of this barite deposit is attributed to the reaction betweenvolcanogenic barium and biogenic sulfur in seawater.

This unique occurrence has been declared as a National Geological

Monument.




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

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

----------Unconformity----------------


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


CuddapahSupergroup


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




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


Cuddapah Basin Nallamalai Group


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Cuddapah Basin- Nallamalai Group Srisailam Quartzite horizontally bedded, glauconite-bearing ferruginous

quartzite overlying Papghni and Nallamalai Groups with profoundunconformity marked by local conglomerate.

Minor shale intercalations are found in the quartzite. Irlakonda Quartzite and Kolamnala Shale , once thought to be part of

Srisailam Quartzite , are now shown to be the equivalents of the CumbumFormation, since Srisailam Quartzite overlies then with angularunconformity at Madapuchelima.

The quartzite is believed to indicate a shallow marine to tidal flatenvironment.




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

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

----------Unconformity----------------Srisailam Quartzite (300 m)

-----------Unconformity --------------

------------------------------------------------------Glauconitic ferruginous quartzite with shale

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

CuddapahSupergroup


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




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

Papaghni Group Vempalle Formation with Kuppalapalle volcanics. Gulcheru Quartzite .

Kurnool Group


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Kurnool Group Jammalamadagu Subgroup: Banganapalle Conglomerate clasts of chert and vein quartz set in a

feeruginous matrix, which is similar to beach gravel formed by

transgressive seas. Well known for placer diamonds derived from kimberlites within and

around the basin. Associated glauconitic sandstones suggest tidal flat environment. The dark grey Narji Limestone indicates restricted circulation, and the

intercalated glauconitic sandstone suggests shallow marine conditions. Auk Shale (Owk Shale) is siliceous and shows near-shore features.

Kurnool

Group(200 -450 m)

KundairSubgroup(75-150 m)


Shale, partly calcareousSiliceous, shaly limestone with quartzite interbeds.Massive and pinnacled qurtzite, siliceous shale,basal pebble bed.

-------------------------JammalamaduguSubgroup(120-260 m)

---------Paraconformity--------------Auk Shale (19-15 m)



---------------------------------------------------------Laminated shale, mostly ochreous with siltstoneinterbeds.Flaggy grey limestone, glauconitic sandstoneinterbeds.Oligomict conglomerate, grit quartzite, shale.

----------------------------------------------------------Angular Unconformity-------------------------------------------------------------------------Tadpatri Formation ,/Srisailam Quartzite ,

Kurnool Group


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Kurnool Group Kundair Subgroup: Paniam Quartzite high degree of roundness and spericity

and mega cross beding suggests near shore environment. Koilkuntla Limestone is a micritic grey limestone depositedin a shallow marine reducing environment.

Nandyal Shale Purple calcareous shale with interbeddedlimestone indicates shallow marine conditions.

The Kurnool sub-basin therefore witnessed strandline, nearshore to shallow marine conditions.

Kurnool

Group(200 -450 m)

KundairSubgroup(75-150 m)


Shale, partly calcareousSiliceous, shaly limestone with quartzite interbeds.Massive and pinnacled qurtzite, siliceous shale,basal pebble bed.

-------------------------JammalamaduguSubgroup(120-260 m)

---------Paraconformity--------------Auk Shale (19-15 m)



---------------------------------------------------------Laminated shale, mostly ochreous with siltstoneinterbeds.Flaggy grey limestone, glauconitic sandstoneinterbeds.Oligomict conglomerate, grit quartzite, shale.

----------------------------------------------------------Angular Unconformity-------------------------------------------------------------------------Tadpatri Formation ,/Srisailam Quartzite ,

Lif i th C dd h S di t


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Life in the Cuddapah Sediments

Stromatolites aboundingin the Cuddapahsediments are not strictlydiagnostic of their age.

Carbonaceousmicrofossils like Ta w u i a ,C h u a r i a in Auk shale,trace fossils in PanianQuartzite and Calcareousalgae form KoiluntlaLimestone indicateNeoproterozoic age forthe Kurnool Group.

Age


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g

Pre-Cuddapah basement dyies are to twoprominent ages at ~2100 and ~2400 Ma.

Rb-Sr dating-dolerite and picrite sills ofPulivendla Formation gives an age of ~1800Ma.

K-Ar ages some dolerite dykes underlyingthe Cuddapah basin are also similar at ~1800Ma.

These dates also correspond to the ageof Umineralization in Lower Cuddapah carbonatesat ~1800 Ma.

Some dolerite dykes of ~1650 Ma age belongto this event. The age of galena and micas in Cumbum

shales (1350-1450 Ma). Younger events recorded by mineral ages

range from 500 to950 Ma, which may span thetime of evolution of Kurnool and Palnad sub-basins.

Kimerlites in the granitic basement near theCuddapah basin generally have an age of ~1050 Ma.

Diamondiferous conglomerate havingkimberlite as its source for diamond, and Rb-Sr age of 980 Ma for dolerite dyke intrudingKuronool sub-basin sugggests Neoproterozoicage for Kurnool Group.

Neoproterozic AgeKurnoolGroup

Kunai Subgroup

JammalamaduguSubgroup

EarlyMesoprotrozoic Age

CuddapahSupergroup

SrisailamQuartzite

EarlyMesoprotrozoic Age Nallamalai Group

EarlyMesoprotrozoic Age Chitravati Group

Palaeoproterozoic Age Papaghni Group


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Documents

Proterozoic Sedimentary Basins