Basin provenance and post-depositional thermal history along the continental P/T boundary of the Raniganj basin, eastern India: Constraints from apatite fission track dating

0016-7622/2014-83-4-403/$ 1.00 © GEOL. SOC. INDIA

JOURNAL GEOLOGICAL SOCIETY OF INDIAVol.83, April 2014, pp.403-413

Basin Provenance and Post-Depositional Thermal History along theContinental P/T Boundary of the Raniganj Basin, Eastern India:

Constraints from Apatite Fission Track Dating

R.C. PATEL1, H. N. SINHA2, BHAIYA ANUPAM KUMAR2 and PARAMJEET SINGH1

1Department of Geophysics, Kurukshetra University, Kurukshetra - 136 1192University Department of Geology, Vinoba Bhave University, Hazaribag - 825 301

Email: [email protected]

Abstract: Apatite fission-track analysis has been applied to the Raniganj and Panchet formations of Raniganj basin ofGondwana Supergroup to unravel its thermal and provenance history. Apatite fission track age population from bothRaniganj and Panchet formations indicate partial annealing and point to a maximum temperature of around ~100-110°Cduring their post depositional evolution. The sandstone of Raniganj Formation has five peak ages at 26.3, 59.3, 109.7,173.7 and 299.9 Ma, while Panchet Formation has three peak ages at 25.4, 143.5 and 281.3 Ma. This implies that theprovenance of the Raniganj Formation of late Permian and Panchet Formation of early Triassic changed obviously.According to thermotectonic evolution of the Gondwana basin, these apatites with different FT ages possibly representdifferent source components, although partial annealing had occurred to these apatites. Possibly all the apatites hadtransported from the Precambrian basement which was undergoing deformation due to Gondwana rifting initiated duringCarboniferous period. Due to this, the basement was undergoing inhomogeneous thermal history which became sourceof sediments for Raniganj basin.

Apatite FT ages of both Raniganj and Panchet formations have peak ages between 25 and 60 Ma, which perhapsrecorded the cooling/uplift history during Cenozoic Alpine-Himalayan orogeny. Given a palaeo-thermal gradient of40° C/km, it can be deduced that the Raniganj basin has uplifted about 3km at an average rate of about 0.09mm/a since25-60 Ma.

Keywords: Apatite fission track, Continental P/T boundary, Raniganj Formation, Panchet Formation, Provenance.

processes and kinematic of Gondwana basin have beenextensively studied during last few decades. Reviews of themain aspects of the Gondwana basin can be found inliterature (Veevers and Tewari, 1995; Biswas, 1999;Mahadevan, 2002; Mukhopadhyay et al., 2010). However,certain aspects concerning the geological history of theGondwana basin, such as the provenance and post-depositional low-temperature evolution of the Gondwanabasin is yet to be understood. Here, we provide an examplefrom the Raniganj basin along the continental P/T sectionconcerning how low-temperature evolution of potentialsources of sediment (provenance ages) and post-sedimentarysuccession in the Raniganj basin can be reconstructedusing the information contained in detrital products of thebasin.

The fission track method is based on the formation ofdamage zones (tracks) in uranium bearing minerals such asapatite, zircon, sphene from the spontaneous fission of 238U

INTRODUCTION

The first Pangean distension by the close of the Paleozoicopened up a number of more or less elongated intra-to pericontinental depressions in which the Gondwanasedimentation began in late Carboniferous. The Gondwanasedimentary basin evolved through a process of deepeningof basins and vertical accretion of sediments. It is nowpreserved in a number of discrete structural basins whichwere formed during Permo-Triassic period (Robinson, 1967;Venkatachala and Maheswari,1988; Veevers and Tewari,1995). The basins define three linear belts along the present-day river valleys of (1) Narmada-Son-Damodar (NSD), (2)Pranhita-Godavari (PG) and (3) Mahanadi (M) (Fig. 1a).Out of these, the NSD is very significant because of manyimportant coal bearing basins such as Satpura, Rewa,Karanpura, Bokarao, Jharia and Raniganj from west to eastare present.

The stratigraphy, palaeogeography, tectonosedimentary

JOUR.GEOL.SOC.INDIA, VOL.83, APRIL 2014

404 R. C. PATEL AND OTHERS

Fig. 1 (a) Regional map of Gondwana rocks in the Peninsular India. Insets show (i) therelative positions of the Gondwana outcrops in the Indian subcontinent and(ii) the Gondwana stratigraphy in the Damodar valley. Note that the Gondwanarocks occur along the valleys of present-day Narmada–Son–Damodar, Pranhita–Godavari and Mahanadi rivers (after Chakraborty et al. 2003), (b) Geologicaland sample map of the Raniganj Basin around Banspetali village, West Bengal(after Sarkar et al. 2003).

over geologic time (Fleischer et al., 1975). A fission trackage is the result of both the time interval of track retentionand amount of annealing during that time (Green, 1988).Below a critical temperature, the closure temperature(Dodson, 1973; 1979) fission tracks begin to accumulate. Ifthe extent and duration of heating is sufficient to anneal allexisting fission tracks in the mineral then the fission trackage will be completely reset. Fission-track analysis hasrecently proved to be a critical tool for unraveling the

thermo-tectonic history of different partsof an orogen (Gallagher, 1995; Gallagherand Brown, 1997; Gallagher et al., 1998).Cooling may reflect either erosional ortectonic exhumation processes or both.The fission track ages of a detrital mineralis the result of the duration of coolingthrough the partial annealing zone(temperature interval in which fission-track lengths are reduced or annealed),transport, and any post-depositionalthermal history (Lonergan and Johnson,1998). In case of detrital minerals whichbring a thermal history recorded in thefission-track length distributation andassociated age, if transport (lag timegiven by Graver and Brandon 1994) isconsidered instantaneous and post-depositional annealing is weak or negli-gible, the thermal history of the sourcescould be reconstructed.

The present work provides new apatitefission track data from the Raniganj basinof eastern India with the aim ofestablishing low-temperature evolution ofpotential sources of sediment and post-depositional thermal history of theRaniganj basin. TheApatite Fission Track(AFT) data presented were obtained fromthe sandstones of Raniganj and Panchetformations (Fig.1b). Their depositional/stratigraphic ages together with FT agesare given in Table 1.

DEPOSITIONAL AND TECTONICHISTORY

The Gondwana basins are extensivelydeveloped in the Gondwanaland ofsouthern hemisphere which comprises ofSouth America, Africa, Australia, India

and Antarctica (Veevers and Tewari, 1995). The commoncharacteristics of these basins of different continents includethe presence of a basal glacial bed, presence of large coalseams, common fossils and an end-phase of volcaniceruption, though not closely contemporaneous. TheGondwana of Peninsular India is confined between Permo-Carboniferous and Triassic (290-208Ma) age (Fox, 1931;Robinson, 1967; Veevers and Tewari, 1995) and preservedin many discrete basins. These basins are confined along


BASIN PROVENANCE AND POST-DEPOSITIONAL THERMAL HISTORY OF THE RANIGANJ BASIN 405

three linear sets along the present day river valleys ofNarmada-Son-Damodar (NSD), Pranhita-Godavari (PG)and Mahanadi (M). The NNW-SSE trending PG andNW-SE trending M belts are sub-parallel to each other andmeet the ENE-WSW trending NSD belt (Chakraborty etal., 2003; Mukhopadhyay et al., 2010). The Gondwanabasins are intracratonic and considered as extensionalrift basins due to the presence of normal faults. Theaccumulation and subsidence of continental sedimentsin the Gondwana basins nucleated along the pre-existingzones of weakness (Precambrian lineaments) and controlledby syn-sedimentary gravity faults (Chakraborty et al., 2003).The Bouguer gravity anomaly study as well as drill-holedata indicate a ~4 km thickness of sub-surface Gondwanastrata (Veevers and Tewari, 1995; Mishra et al., 1999).Permo-Carboniferous glaciogenic deposits at the base ofthe individual basins describe their evolution due to aglobal tectonic event (Veevers and Tewari, 1995; Casshyapand Tewari, 1999; Biswas, 1999). Fault analysis fromGondwana basins indicates that all the Gondwana basinsdeveloped under a single tectonic regime characterizedby a roughly E-W motion. This caused preferentialsubsidence in locales of preexisting discontinuities in thePrecambrian basement and led to the development of anarray of sedimentary basins of varied kinematics alongthe present day river valleys of Narmada-Son-Damodar,Pranhita-Godavari and Mahanadi (Chakraborty et al.,2003).

It is accepted that the Gondwana sedimentation beganaround ~302 Ma and subsidence of basin floor continuedtill ~184 Ma to accommodate the entire pile of Gondwanasediments (Mukhopadhyay et al., 2010). It was then followedby a period of quiescence for 135 million years i.e. upto70 Ma. Then uplift and erosion began during CenozoicHimalayan-Alpine orogeny and continued till date (Bardhanand Ghosh, 1999). Volatile matter and oil reflectance ofvitrinite studied from the coal samples from the deepestboreholes from the Damodar valley revealed that maximumpalaeodepth of the basin floor was 3920m in Jharia; 3650min Raniganj, 3850m in east Bokaro, and 3040m in southKaranpura basins during 260 to 205Ma (Bardhan andGhosh, 1999). The palaeotemperature attained was 155° Cin Jharia, 150° C in east Bokaro, 110°C in south Karanpuraand 135° C in Raniganj (Bardhan and Ghosh, 1999). Thegeothermal gradient of the NSD basins range between57° C/km and 31° C/km with average being 40° C/km(Bardhan and Ghosh, 1999).

The present work is confined to Raniganj Basin(Fig. 1a) which is rhomb-shaped, 70km long and 20km wideand bounded by several faults. The basin profile reveals a

fault-controlled subsidence (Fox, 1931). This basin is oneof the most significant Gondwana basins of India comprisingseveral conformable successions (Fig. 1a). The successionresting unconformably over older Precambrian rocks andrepresented by early Permian Talchair Formation of DamudaGroup. The Talchair Formation represents glacial andglacio-fluvial origin and well correlatable with Dwyka andBuckeye tillites of South Africa and Antarctica respectively(Sarkar et al., 2003). The rest of the formations of DamudaGroup comprising from older to younger are Barakar,Ironstone Shale (Barren Measures) and Raniganj Formationare attributed as fluvial deposits. The palaeoflow dominantlyvaries from NNW to W (Veevers and Tewari, 1995).Disconformable relation between Raniganj and overlyingPanchet formation in Raniganj basin has been markedbased on the presence of palaeosol horizons at the contactbetween Raniganj Formation and overlying Triassic deposits(Gee, 1932). At places, it is marked by a minor angularunconformity (Ghosh et al., 1994). The contact is delineatedby a local unconformity near Banspetali village which islocated at ~160km WNW of Kolkatta. This Banspetalisection (Fig. 1b) is considered as the type continental P/Tsection of India (Ghosh et al., 1994).

Lithologically, the Raniganj Formation comprises ofalternate sequence of sandstone, shale and coal. The white/grey sandstones are plagioclase rich and texturally fine tomedium grained. The shales are dark and rich incarbonaceous materials. On the contrary, the PanchetFormation is made up of a thick sequence of yellow or buffto khaki-green coloured medium to coarse grained sandstonewith abundant cross-stratification, greenish shales andsiltstone. The topmost litho-unit in the area is red coloured,highly immature, poorly sorted, pebbly sandstone andconglomerate of Supra-Panchet Formation of possibly lateTriassic age (Sarkar et al., 2003).

PREVIOUS FISSION TRACK THERMO-CHRONOLOGICAL STUDIES FROM

THE GONDAWANA BASIN

Apatite and zircon fission track studies have beencarried from the Talchir and Ib river basins along theMahanadi region to understand the mechanism of the basinformation and denudational history since early Palaeozoic(Lisker and Fachmann, 2001). Eight AFT and five ZFT agesfrom the Talchir Formation (Depositional age ~290-274 Ma)have been determined. TheAFT ages range from 443±28 to181±13 Ma and ZFT ages range between 314±32 and419±42 Ma. The scatter of single-grain ages of thesesamples is ascribed to deposition of sediments from



Tabl

e 1.

Det

rital

Apa

tite

Fiss

ion-

Trac

k ag

es fr

om th

e R

anig

anj a

nd P

anch

et fo

rmat

ions

of R

anig

anj B

asin

, Eas

tern

Indi

a

S.Sa

mpl

eFo

rmat

ion

Nρ d

× 10

5 cm-2

ρ s×

105 cm

-2ρ i×

105 c

m-2

U in

Cen

tralA

geA

ge p

opul

atio

n (M

a) (%

of g

rain

s)

No

No.

(Stra

tigra

phic

( Nd)

( Ns)

( Ni)

ppm

(Ma)

P1P2

P3P4

P5ag

e in

Ma)

P (χ

2 ) %

1R

1R

anig

anj

096.

472

0.31

250.

1893

35.1

159.

6±13

.011

7.9±

13.3

171.

9±18

.9-

---

(260

to 2

51)

(323

6)28

2617

490.

00(3

3.4)

(66.

4)W

–0.1

0W

- 0.1

2

2R

232

6.47

20.

2971

0.20

6938

.412

3.2±

15.9

30.0

±4.4

59.2

±6.9

108.

3±12

.320

0.5±

21.5

-(3

236)

5239

3729

0.00

(12.

1)(1

5.9)

(10.

1)(6

1.9)

W–0

.25

W–0

.15

W–0

.10

W–0

.15

3R

324

6.47

20.

3053

0.19

1435

.513

1.3±

24.7

140.

2 ±1

4.8

303.

6 ±3

3.8

--

-(3

236)

5635

3781

0.00

(59.

6)(4

0.4)

W–0

.11

W–0

.18

4R

424

6.47

20.

3292

0.21

9440

.714

7.4±

19.2

33.0

±3.

418

9.0

±19.

9-

--

(323

6) 4

525

325

60.

00(1

3.0)

(87.

0)W

–0.1

2W

–0.1

4

5R

1+R

2+89

22.4

to26

.3 ±

3.0

59.3

±6.

810

9.7

±11.

617

3.7

±18.

129

9.9

±32.

1R

3+R

4 4

66.0

(6.4

)(6

.5)

(17.

0)(4

8.4)

(21.

6)W

–0.1

6W

–0.1

6W

–0.1

1W

–0.1

3W

–0.1

6

6P3

Panc

het

366.

472

0.38

430.

1988

36.9

201.

6±14

.994

.7 ±

11.2

158.

2 ±1

6.6

310.

8 ±3

4.3

(251

to 2

45)

(323

6) 8

553

449

3 0

.00

(9.3

)(5

7.9)

(32.

8)-

-W

– 0

.13

W–0

.12

W –

0.1

5

7P4

106.

472

0.31

100.

2086

38.7

113.

5±21

.425

.5 ±

6.5

155.

2 ±

16.7

--

-(3

236)

215

3 1

972

0.0

0 (1

9.3)

(80.

7)W

–0.2

6 W

– 0

.12

8P1

+P2

4625

.4 to

25.4

±4.

714

3.5

±15.

028

1.1

±30.

0-

-76

0.6

(3.7

)(6

4.1)

(32.

3)W

–0.2

5W

– 0

.12

W –

0.1

4

N: N

umbe

r of g

rain

s, N

s is

num

ber o

f spo

ntan

eous

trac

k co

unte

d, N

i is

num

ber o

f ind

uced

trac

k co

unte

d, N

d is

num

ber o

f ind

uced

trac

ks c

ount

ed in

dos

imet

er g

lass

. Zet

a va

lue

of 2

98.7

±6.1

4 fo

rdo

sim

eter

gla

ss C

N5

is u

sed.

Cen

tral a

ge is

a m

odal

age

, wei

ghte

d fo

r diff

eren

t pre

cisi

ons

of in

divi

dual

cry

stal

s (s

ee G

albr

aith

, 198

1).

P (χ

2 ): C

hi s

quar

e pr

obab

ility

.



various provenances associated with different cooling history(Lisker and Fachmann, 2001).

Fission Track Thermochronology

Analytical and Experimental Methods

All sandstone samples were about 5kg in weight.Several samples were collected from the upper part of theRaniganj Formation and bottom part of the PanchetFormation. Out of these, six samples yielded sufficientnumber of apatite grains. No sample yielded adequatenumbers of zircon. Apatite concentrates were preparedusing a conventional crushing and separation technique.Analytical FT procedure was followed (Hurford, 1990) forapatite. Grains were mounted in epoxy. To reveal internalsurfaces, apatite mounts were ground and polished indiamond pastes and then etched in 1% HNO3 at 30°Cfor 60 seconds. An “external detector” (Naeser, 1979)muscovite mica of low-U content (<5ppb) was used toobtain the induced track densities. CN-5 dosimeter glasswas used and irradiation of samples was performed at thethermal neutron facility of the Cirus reactor, Board ofRadiation and Technology (BRIT), Bombay, India. Afterirradiation, the external mica detectors were detached andetched in 48% HF at 35°C for 4 minutes. Glass standardand induced track densities were measured on externaldetector (with a geometry factor of 0.5) after etching andspontaneous track densities were determined on internalmineral surfaces using an olympus optical microscope with100x dry lens and total magnification of 1250x. Ages (± 1s)were calculated using zeta approach (Hurford and Green,1983) with a zeta factor of 298.7 ± 6.14 (for CN-5 glass)for apatite. The zeta factor is determined by multiple analysesof apatite standards (Hurford, 1990). Only crystals withprismatic sections parallel to the c-crystallographic axiswere accepted for analysis.

The ages were calculated using the following ageequation (Hurford, 1990):

t = 1/λd ln [ 1+ λd ξ ρs/ ρi g ρd ]

Whereλd = Total decay constant for uranium (1.55125 x 10-10

yr-1)ξ = Zeta factorρs = Spontaneous track density measured on the mineral

surfaceρi = Induced track densities measured on mica detectors

attached to mineral surface.g = Geometry correction factor. For an internal crystal

surface this will be 4π and for an external surface,

as in mica detector will be = 2π. Thus for externaldetector method g =0.5 (2π /4π ) (Green et al.,1986)

ρd = Induced track densities measured on glassdosimeter.

Data Analysis

The analyzed results are listed in Table 1. Detrital apatitefission track dating has become one of the most importanttechniques for deciphering the source character andexhumation history of the provenances because this commonaccessory mineral has a FT closure temperature of 110 ±10° C (Wagner and Van den haute, 1992; Yamada et al.,1995; Tagami et al., 1996; Gailbrath, 1981). If the apatitesin a sample derived from the same source rock, the averageFT age of these apatites can be taken as the FT age of thesample. However, if the apatites in a sample derived fromdifferent source areas and were not reset totally afterdeposition, the average FT age is a mix age of differentsource rocks and has no real geological meaning. It isunreasonable to take average FT age as the fission track ageof the sample directly.

The χ2 method is very effective technique to determinewhether the measured ages belong to a single group or moreage groups. When p (χ2) < 5, the measured FT ages arecomposed of several age groups and needed to be furtherdistinguished through other methods (Green, 1981;Brandon, 1996). The samples from the present study areafail the χ2 test. Their ages reflect a mixture of many fissiontrack components. Distributation of grain ages isdecomposed into individual age components by statisticaltechniques to discriminate distinct populations (Green, 1981;Brandon, 2002). Using the binomial peak-fitting routine,the BINOFIT software (Brandon, 2002; Brown et al., 1994)has been applied in this work to decompose the observedgrain age distribution into different peaks (Table 1). ApatiteFT grain age distribution from different samples is indicatedon radial plots (Figs. 2a, c and 3a, c, e and g) and probabilitydensity plots with full grain age spectrum, binomial-fittedpeaks, and their ages in Figs. 2b, d and 3b, d, f and h.

Since the basin provenance is not similar, hence, everysample possibly includes the apatites derived from differentsources. If the sample has remained in the upper most partof the crust and did not experience a post-depositionalthermal history sufficient to cause track annealing totally(e.g. at a temperature less than 120° C), then the apatiteswould not be reset completely after deposition. Thus, thesingle grain apatite FT age would preserve some informationabout the source regions from which the grains were eroded.Due to the fact that the apatites in a single sample undergo



the same thermal history after the deposition, it can bededuced that several source rocks with different thermalevolution should be involved in the basin sediments, if thesingle grained apatite FT ages of a sample are composed ofseveral age components. Although these apatites perhapsalready have been reset partially and we could not knowwhether the FT ages related to the original provenance orpost-depositional partial annealing, it is feasible to explorethe possible source information from the FT ages when weknow more details about the regional thermo-tectonichistory.

RESULTS

Analytical data are listed in table 1 and the locations ofsamples are shown in Fig.1b.The radial plots and probabilityspectrum plots of all samples are shown in Figs. 2 and 3.Synoptic radial and probability plots of the Panchet andRaniganj formations are also shown in Fig. 4. The Panchetsample P3 has two populations of apatite grains younger(94.7 Ma and 158.2 Ma) than the depositional age (251 to

245 Ma) and a population much older than 310 Ma. In otherPanchet sample (P4) the number of grains is few (10) andtwo populations of grain age can be distinguished (25.5 and155.2 Ma) which are younger than the depositional age. Thesynoptic plots (Fig. 4) of both samples show two significantpeaks at 143.5 Ma which is younger than the depositionalage and another at 281.1 Ma which is older than thedepositional age.

In the Raniganj samples R1, R2 and R4 almost all

Fig.2. (a) and (c) Radial distribution plot of detrital-apatite fission-track ages from the Panchet formation, Raniganj Basin. X-axis denotes standard error (SE) of log of age (z), which isapproximately equal to relative standard error (RSE). (b)and (d) Composite probability density distribution andgrain-age histograms for the detrital-apatite fission-track(FT) ages from the Panchet Formation using theBINOMFIT peak-fit program. Also shown with bars arethe prominent peaks and their distinct characters.

Fig.3. (a), (c), (e) and (g) Radial distribution plot of detrital-apatitefission-track ages from the Raniganj Formation, RaniganjBasin. X-axis denotes standard error (SE) of log of age (z),which is approximately equal to relative standard error(RSE). (b), (d), (f) and (h) Composite probability densitydistribution and grain-age histograms for the detrital-apatitefission-track (FT) ages from the Raniganj Formation usingthe BINOMFIT peak-fit program. Also shown with barsare the prominent peaks and their distinct characters.

Panchet FormationSample No. P3

Raniganj Formation



individual apatite fission track ages are younger than thedepositional age (260 to 251 Ma). In sample R3 an olderpopulation (303.6 Ma) and another younger population(140.2 Ma) are recognized. In the synoptic plots of allRaniganj samples there are three prominent peaks at 109.7,173.7 and 299.9 Ma. The other two insignificant peaksat 26.3 and 59.3 Ma are also noticed but not considereddue to poor yield.

DISCUSSION: GEOLOGICAL INTERPRETATION

Fission track analysis is a geochronological method anda powerful tool for a variety of different applications. It isprimarily used to determine the ages of various geologicalprocesses, including exhumation (denudation) and coolingof metamorphic and igneous rocks (Gallagher et al., 1998;Carter, 1999), but is also equally useful in sedimentaryprovenance studies (Lal et al. 1976). Since the most reliableage assessment of the Gondwana sediments is based onbiostratigraphy (Mahadevan, 2002), our aim is to reconstructprovenance history and low-temperature history of the

Raniganj basin by combining the newly obtained apatiteFT ages along with previously published biostratigraphicages, volatile matter and oil reflectance studies of vitrinite(Bardhan and Ghosh, 1999).

Pre-depositional and Burial History

After the Pan-African episode, the Indian cratonicbasement remained relatively stable until the lateCarboniferous. It is estimated that the craton along withBihar Mica belt (presently in Jharkhand) was exhuming veryslowly (~0.08 mma-1) and steadily since 950 Ma and theregion has been near the surface for the last ~600 Ma (Lalet al., 1976). The intrusion of this mica belt is described tobe associated with the development of the Son-Narmadadeep-seated fracture lineament which cuts across the IndianPeninsula (Auden, 1949). This lineament is believed to beoriginated during Proterozoic (Quareshi, 1970; Naqvi et al.,1974; Casshyap and Tewari, 1988). This pre-existing zoneof weakness became zone of basins resulting from strike-slip movements and oblique, asymmetric extension (Fox,1931). This phase started in early Permian and lasted tillTriassic when accumulation of thick sedimentary pilesoccurred. Northwestern palaeocurrent directions (Lisker andFachmann, 2001) suggest that the main provenance was thehighlands of the Eastern ghats in the southeast and theAntarctic shield (Veevers and Tewari, 1995). Glaciogenicsediments of Talchir were deposited in the rift valleys in thevicinity of the palaeo-channel by the north flowing glaciersfrom the southeastern highland. Barakar sediments weredeposited as syn-rift basin fill in the evolving rift grabens.Post Barakar sediments were deposited after the basindifferentiation and the depo-centers were shifted toindividual grabens (Biswas, 1999).

Based on the study of the regional tectonic evolution,the detritus composition and filling sequence of the Raniganjbasin, we assume that the five major age groups possiblyrepresent five different provenances undergoing differentcooling history. Apatites of oldest peak age (300 Ma)possibly originated from a region which was older than thePermian undergoing slow cooling, while, the apatites of110 and 174 Ma came from the provenances which wereolder than the Permian but undergoing differential coolingrates faster than previous source. Probably, apatites of174 Ma were derived from the region undergoing moderatecooling while apatites of 110 Ma was cooling faster thanthe above source regions. Similarly, apatites of youngestage groups (59 and 26 Ma) were also transported from pre-Permian source region which were undergoing faster coolingthan the other source regions. It implies that the RaniganjFormation was receiving sediments from pre-Permian

Fig.4. (a) and (c) Synoptic radial distribution plot of detrital-apatitefission-track ages from the Panchet and Raniganjformations respectively. X-axis denotes standard error (SE)of log of age (z), which is approximately equal to relativestandard error (RSE). (b) and (d) Composite probabilitydensity distribution and grain-age histograms for thedetrital-apatite fission-track (FT) ages from the Panchetand Raniganj formations using the BINOMFIT peak-fitprogram. Also shown with bars are the prominent peaksand their distinct characters.

Panchet Formation



provenances which were undergoing differentiated cooling/denudation history.AFT study (Lisker and Fachmann, 2001)from the basement rocks surrounding the Mahanadi basinreveals a very inconsistent result and cover a broad range ofages between 368±34 to 119±6 Ma. The youngest AFT agesare found close to or along the shear zone while older agesare located away from the shear zones. This pattern isdescribed due to differentiated cooling/denudation sincePalaeozoic. The youngest AFT ages close to shear zoneare due to hydrothermal influences associated with faulting(Lisker and Fachmann, 2001). Similar tectonic environmentdue to Gondwana rifting during Carboniferous along theNSD might be possible cause for the evolution ofprovenances of differentiated cooling/denudation duringCarboniferous-Permian time from where sediments weretransported to Raniganj basin. Sedimentary rocks of theRaniganj basin are deposited over the Precambrian basementand buried to a maximum depth of 3650 m (Bardhan andGhosh ,1999). The Raniganj Formation was deposited overthe Barren Measures and buried to ~3000 meter depth. Themaximum burial of Raniganj samples reached 3000 meter,indicative of heating at temperature ~100 to 1100 C whichfalls in the partial annealing zone (PAZ) of apatite. It isevident that this burial temperature was sufficient to reducethe apatite fission track length as they were at the higherlimit of the PAZ (~100 to 110° C) so the AFT ages areyounger.

AFT ages from the Panchet show three groups of age at25.4, 143.5 and 281.1 Ma. All groups of apatite can beexplained from different pre-Panchet provenances whichwere undergoing differential cooling/denudation history. ThePanchet Formation was deposited over the RaniganjFormation and buried to a depth of around ~2500 meterindicative of heating temperature at ~90-100º C whichrepresents the zone of partial annealing of apatite fissiontrack. In this temperature range, the apatite fission tracklength reduced due to which the ages are younger.

In fact the sandstone of the Raniganj Formation attributesfive peak ages and the sandstone of Panchet Formation hasthree peak ages which suggests that the provenance ofRaniganj Formation of late Permian and Panchet Formationof early Triassic changed obviously, which responded wellto the regional tectonic-setting. Lithological and bioticstudies across the Raniganj-Panchet boundary also supportsome pronounced tectonic change which was also associatedwith major climate, provenance and erosional base levelchanges across Permian-Triassic boundary (Sarkar et al.,2003). The palynological study recorded several changesalong the P/T boundary. Palynoflora such as Callumisporasp. vanishes from late Permian and reappeared at the

beginning of the Panchet Formation which decides Raniganj-Panchet boundary transition zone (Vijaya, 1995;Vaidyanadhan and Ramakrishnan, 2008). Striate disaccateand Densipollenites rich mioflora marks the end ofPermian and appearance of new set such as Densoisporites,Lunatisporites etc. marks the beginning of Triassic alongthe study section (Ghose et al., 1994). After the rifting ofthe Gondwana basin during Permo-Carboniferous period,the wide spread coal bearing clastics sediments from thewide surrounding land mass were deposited in the RaniganjFormation. Rounded to sub-rounded, well sorted, low matrixand matured texture of Raniganj sediments reflecttransportation of sediments for long distance from the regionof landmass which was undergoing differential cooling/denudation history. The migration of upward finingsedimentary succession of the Raniganj Formation(Vaidyanadhan and Ramakrishnan, 2008) indicates the stablesubsidence setting of the basin. The Raniganj basin subsidedslowly and stably and the surrounding regions upliftedinhomogeneously.

Two stages of rifting process in the late Permian to earlyTriassic and the middle Triassic have been ascribed toinfluence the sedimentation phases of the lower and upperGondawana sediments in the Mahanadi basin (Lisker andFachmann, 2001). Similar tectonic event during the latePermian-early Triassic has influenced the regional tectonicsetting remarkably in the Raniganj basin due to whichprovenance of Panchet sediments confined to limited region.Three peak apatite FT ages from the Panchet sandstonereflect only three provenances from where sediments weretransported. Angular, high matrix and immature texture ofPanchet sandstone (Sarkar et al., 2003) reflect nearby sourceregion close to the Raniganj basin. Traces of palaeosols asdiastems indicate silent march of time during the Panchetdeposition (Ghosh et al., 1994).

Final Uplift History

Spectrum of AFT ages from the Raniganj and Panchetformations indicate that the sediments buried to a depth of~3km which is the partial annealing zone of apatite (Fig. 5).The sediments achieved temperature upto 100 to 110º C. Itis accepted that the Gondwana sedimentation began around~302 Ma and subsidence of basin floor continued till ~184Ma to accommodate the entire pile of Gondwana sediments(Mukopadhyay et al., 2010). Probably this is the time duringwhich the Raniganj and Panchet sediments were buried to adepth where the temperature was 100° to 110º C. Then thetemperature remained the same for long time during whichsome apatites transported from faster cooling provenances(i.e. AFT age of the sediments was older but close to the



depositional ages) probably completely annealed and recordvery young ages i.e. between 25 and 60 Ma. Probably thisis the time during which the Raniganj basin started upliftingdue to Cenozoic Himalayan-Alpine orogeny and continuedtill date (Casshyap and Tewari, 1999). The geothermalgradient of the NSD basins ranges between 57° C/km and31° C/km with average being 44/40° C/km (Casshyap andTewari, 1999). If the AFT peak age of 25-60 Ma did reflectrecent event of uplift, then it is reasonable to estimate thatthe Raniganj basin uplifted from ~3km since 25 to 60 Mawith average uplift rate 0.09mm/a

CONCLUSIONS

Different apatite age components were identified in theRaniganj and Panchet formations along the P/T section ofthe study area. The spectrum of ages ranges from young(Younger than the depositional age) to old (Older than thedepositional ages). The young age components are furthersub-grouped to many sub-components. These apatites withdifferent FT ages likely represent different sourcecomponents although partial annealing had occurred. Theapatites of oldest peak ages possibly transported from thePrecambrian basement which was undergoing slow coolingand not affected by later thermal event such as faulting,

hydrothermal activity. The apatites of younger componentsmust have derived from Pre-Permian sources withinhomogeneous cooling history. Number of age componentsreduces from the Raniganj to Panchet formations whichreflect that Raniganj Formation was receiving sedimentsfrom wide provenance which was undergoing differentialcooling/denudation history, while at the time of Panchetdeposition the provenance was confined to a limited region.It means there was a transition of tectonic and climaticconditions at the Permo-Triassic boundary.

The AFT data suggest that the sedimentary rocks of theRaniganj and Panchet formations of Raniganj basin wereburied to a depth of ~3km with maximum temperaturesof ~100° to 110° C. AFT ages of both Raniganj and Panchetformations have peak age between 25 to 60 Ma, whichperhaps represent the time of beginning of uplift of theRaniganj basin due to Cenozoic Alpine-Himalayanorogeny.

Acknowledgements: The authors are highly grateful tothe National Facility, Department of Geophysics,Kurukshetra University, Kurukshetra where the FissionTrack Dating work was carried out. We are also thankful toDST, New Delhi for providing financial assistance toestablish this national facility in Fission Track Dating atKurukshetra University due to which this work wascompleted successfully. Constant encouragement andunending enthusiasm received form Prof. Nand Lal,Department of Geophysics, Kurukshetra University,Kurukshetra and Dr. Monoranjan Mohanty, Scientist, DST,New Delhi are main source of inspiration that made ourwork successful and we greatly acknowledge it. HNS thanksProf. P.P. Chakroborty of Delhi University for fruitfuldiscussion on field aspects. The support and infrastructurefacilities provided by our Chairman, Department ofGeophysics, Kurukshetra University, Kurukshetra is highlyappreciated and we are very grateful to him. HNS thanksDr. Laxmi for the support in many ways. The authors alsothank an anonymous reviewer for his valuable comments inimproving the manuscript.

Fig. 5. Schematic diagram of thermal history of the Raniganj Basin,Damodar valley.

References

AUDEN, J.B. (1949) In Director’s report for 1939. Rec. Geol. Surv.India, v.78, pp.74-78.

BARDHAN, B. and GHOSH,A. (1999) Palaeotemperature-palaeodepthstudy from selected coal Basins of Damodar valley coalfields,India. Jour. Geol. Soc. India, v.53, pp.509-536.

BISWAS, S.K. (1999) A review on the evolution of rift Basins inIndia during Gondawana with special reference to western

Indian Basins and their hydrocarbon prospects, PINSA , v.65A(3), pp.261-283.

BRANDON, M.T. (1996) Probability density plot for fission trackgrain-age samples. Radiation Measurements, v.26, pp.663-676,doi:10.1016/S1350-4487(97)82880-6.

BRANDON, M.T. (2002) Decomposition of mixed grain agedistributions using binomfit. On track, v.24, pp.13-18.



BROWN, R.W., SUMMERFIELD, M.A. and GLEADOW, A.J. (1994)Apatite Fission Track analysis:its potential for the estimationof denudation rates and implications for models of long-termlandscape development. In: M.J. Kirkby (Ed.), Process Modelsand Theroretical Geomorphology. Wiley, Chichester, pp.23-53.

CARTER, A. (1999) Present status and future avenues of sourceregion discrimination and characterization using fission trackanalysis. Sediment. Geol., v.124, pp.31-45.

CASSHYAP, S.M. and TEWARI, R.C. (1988) Depositional model andtectonic evolution of Gondawana Basins. Paleobotanists, v.36,pp.59-66.

CASSHYAP, S.M. and TEWARI, R.C. (1999) Depositional model andtectonic evolution of Gondwana Basins. In: B.S. Venkatachalaand H.K. Maheswari (Eds.), Indian Gondwana. Mem. Geol.Soc. India, v.21, pp.95-206.

CHAKRABORTY C. MANDAL, N. and GHOSH, S.K. (2003) Kinematicsof Gondawana Basins of peninsular India. Tectonophysics,v.377, pp.299-324.

DODSON, M.E. (1973) Closure temperature in coolinggeochronological and petrological systems. Contrib. Mineral.Petrol., v.40, pp.259-274.

DODSON, M.E. (1979) Theory of cooling ages. In: E. Jaeger, E.and J.C. Hunziker (Eds), Lectures in Isotope Geology, Berlin,Springer-Verlag, pp.329.

FLEISCHER, R.L., PRICE, P.B. and WALKER, R.M.(1975) Nucleartracks in Solids, Berkley, CA, Univ. California Press, pp.605.

FOX, C.S. (1931) The Gondawana system and related formations.Mem. Geol. Surv. India, v.58, pp.241.

GAILBRATH, R.F. (1981) On statistical models for fission trackcounts. Mathematical Geol., v.13, pp.471-478.

GALLAGHER, K. and BROWN, R.W. (1997) The onshore record ofpassive margin evolution. Jour. Geol. Soc. London, v.154,pp.451-457.

GALLAGHER, K.(1995) Evolving temperature histories from apatitefission-track data. Earth Planet. Sci. Lett., v.136, pp.421-435.

GALLAGHER, K., BROWN, R.W. and JOHNSON, C.J. (1998) Geologicalapplications of fission track analysis. Annual Rev. Earth PlanetSci., v.26, pp.519-572.

GEE, E. R. (1932) The Geology and Coal Resources of the RaniganjCoalfield. Mem.Geol. Surv. India, v.61, pp.1-343.

GHOSH, S.C., NANDI, A., AHMED, G. and ROY, D.K. (1994) Study ofPermo-Triassic Boundary in Gondawana sequence of RaniganjBasin, India. Ninth Internat. Gondawana Symp., v.1, pp.179-193.

GRAVER, J.I. and BRANDON, M.T. (1994) Erosional denudation ofthe British Columbia Coast Region as determined from fission-track ages of detrital zircon from the Tofino Basin, OlympicPeninsula, Washington. Geol. Soc. Amer. Bull., v.106,pp.1398-1412.

GREEN, P.F. (1981) A new look at statistics in fission-track dating.Nuclear Tracks, v.5, pp.77-86.

GREEN, P.F. (1988) The relationship between track shortening andfission-track age reduction in apatite: combined influences ofinherent instability, annealing anisotropy, and length bias and

system calibration. Earth Planet. Sci. Lett., v.89, pp.335-352.GREEN, P.F., DUDDY, I.R., GLEADOW, A.J.W., LASLETT, G.M. and

TINGATE, P.R. (1986) Thermal annealing of fission tracks inapatite, 1. A qualitative description. Chemical Geol., v.59,pp.237-253.

HURFORD, A.J. (1990) Standardization of fission track datingcalibration: Recommendation by the fission track WorkingGroup of the IUGS Subcommission on Geochronology.Chemical Geol., v.80, pp.171-178.

HURFORD, A.J. and GREEN, P.F. (1983) The zeta calibration offission-track dating. Chemical Geol., Isot. Geosci. Sect., v.1,pp.285-317.

LAL , N., SAINI, H.S., NAGPAUL, K.K. and SHARMA, K.K. (1976)Tectonic and cooling history of the Bihar Mica belt, India, asrevealed by fission-track analysis. Tectonophysics, v.34,pp.163-180.

LISKER, F. and FACHMANN, S. (2001) Phanerozoic history of theMahanadi region, India. Jour. Geophys. Res., v.106, pp.22,027-22,050.

LONERGAN, L. and JOHNSON, C. (1998) A novel approach forreconstructing the denudation histories of mountain belts: withan example from the Betic Cordillera (S. Spain). Basin Res.,v.10, pp.353-364.

MAHADEVAN, T.M. (2002) Geology of Bihar and Jharkhand.Geological Society of India, Bangalore, 563p.

MISHRA, D.C., CHANDRA SEKHAR, D.V., VENKATA RAJU, D.CH. andVIJAY KUMAR, V. (1999) Crustal structure based on gravity-magnetic modeling constrained from seismic studies underLambert Rift, Antarctica and Godavari and Mahanadi rifts,India and their interrelationship. Earth Planet. Sci. Lett., v.172,pp.287-300.

MUKHOPADHYAY, G., MUKHOPADHYAY, S.K., ROY CHOWDHURY, M. andPARUI, P.K. (2010) Stratigraphic Correlation between DifferentGondwana Basins of India, Jour. Geol. Soc. India, v.76,pp.251-266.

NAESER, C.W. (1979) Fission-track dating and geologic annealingof fission tracks. In: E. Jager and J.C. Hunziker (Eds.), Lecturesin Isotope Geology: New York, Springer-Verlag, pp.154-169.

NAQVI, S.M., DIVAKARA, RAO, V. and NARAIN, H. (1974) Theprotocontinental growth of the Indian schield and the antiquityof its rift valleys. Precambrian Res., v.1, pp.345.

QUARESHI, M.N. (1970) Relation of gravity to allevation, geologyand tectonics in India. In: H. Narain (Ed.), Proc. 2nd U.M.P.Symp., Hyderabad, pp.1-24.

ROBINSON, P.L. (1967) The Indian Gondwana formations —areview. First Symposium on Gondwana Stratigraphy, Mar DelPlata, Argentina. UNESCO, Paris, pp.201-268.

SARKAR, A., YOSHIOKA, H., EBIHARA, M. and NARAOKA, H. (2003)Geochemical and Basinic carbon isotope studies across thecontinental Permo-Triassic boundary of Raniganj Basin,eastern India. Palaeogeo., Palaeoclimat., Palaeoeco., v.191,pp.1-14.

TAGAMI, T., CARTER, A. and HURFORD, A.J. (1996) Natural long-term annealing of the zircon fission-track system in ViennaBasin deep borehole samples: Constraints upon the partial



annealing zone and closure temperature. Chem. Geol., v.130,pp.147-157.

VAIDYANADHAN, R. and RAMAKRISHNAN, M. (2008) Geology of India.Geological Society of India, Bangalore, v.2, pp.994.

VEEVERS, J.J. and TEWARI, R.C. (1995) Gondwana master Basin ofpeninsular India between Tethys and the interior of theGondwanaland province of Pangea. Mem. Geol. Soc. Amer.,v.187, pp.1-73.

VENKATACHALA, B.S. and MAHESWARI, H.K.(1988) IndianGondwana-redefined. 7th International Gondwana Symposium,

Sao Paulo, BSIP, University of Lucknow, India, pp. 539-547.VIJAYA (1995) Palynostratigraphy of Permian sequence in India.

In: R.S. Tiwari (Ed.), Coaliferous fuel resources of India:Parameters of studies in Palynology and Biopetrology. BSIPPubl., pp.124-152.

WAGNER, G.A. and VAN DEN HAUTE, P. (1992) Fission-track dating.Stuttgart: Ferdinand Enke Verlag, 285p.

YAMADA, R., TAGAMI, T., NISHIMURA, S. and ITO, H. (1995)Annealing kinetics of fission-tracks in zircon: An experimentalstudy. Chemical Geol., v.122, pp.249-258.

(Received: 26 October 2012; Revised form accepted: 23 March 2013)

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Basin provenance and post-depositional thermal history along the continental P/T boundary of the Raniganj basin, eastern India: Constraints from apatite fission track dating