Palynostratigraphic zonation and correlation of the Eocene-Early Miocene sequence in Alleppey district, Kerala, India

E L S EVI ER

Review of Palaeobotany and Palynology86 (1995) 325-348

REVIEW OF PALAEOBOTANY AND PALYNOLOGY

Palynostratigraphic zonation and correlation of the Eocene-Early Miocene sequence in Alleppey district, Kerala, India M.R. Rao Birbal Sahni Institute of Palaeobotany, 53 University Road, Lucknow-226007, India Received 30 November 1992; revised and accepted 28 September 1994

Abstract

Two palynological assemblages consisting of pteridophyte spores and angiosperm pollen have been recovered from the Kalarakod and Nirkunnam bore-holes, Alleppey district, Kerala. In the Kalarakod palynoflora, 49 genera and 62 species have been recognised. Out of these, 14 genera and 18 species belong to pteridophyte spores and 35 genera and 44 species are referable to angiosperm pollen. Compositoipollenites alleppeyensis, Myricipites singhii, Bacutriporites venkatachalae, Ornatetradites keralaensis and Verrualetes kalarakodensis have been established as new species. In the Nirkunnam assemblage, 9 genera and 14 species of pteridophyte spores and 22 genera and 25 species of angiosperm pollen have been recognised. Qualitative and quantitative dominance of angiosperm pollen is a conspicuous feature of the assemblage. The palynological succession has been divided into three cenozones, namely the Triangulorites bellus Cenozone, the Crassoretitriletes vanraadshooveni Cenozone and the Malvacearumpollis bakonyensis Cenozone. Palynological data indicate a warm and humid climate with high rainfall during the time of deposition. Ecological analysis of the assemblage identifies several palaeo-associations of low-land, freshwater swamp and water edge, sandy beach and back-mangrove vegetation. A brackish water deposition environment is indicated by back-mangrove elements and dinoflagellate cysts. The palynological succession ranges from Eocene to Early Miocene in age.

1. Introduction

Palynofossils were recovered from the Kalarakod (9°27'30": 76°20'00 ") and Nirkunnam (9°23'30": 76022'00 ") bore-holes (610 and 267 m depth, respectively) in the Alleppey district, Kerala. The Kalarakod bore-hole is located on private land belonging to Mr Narayana Bhakte, Yuvajana Sangam, adjoining the Alleppey Medical College. The site is 4 km south of Alleppey and 1 km east of the Arabian sea shoreline. The area is covered by unconsolidated coastal alluvium comprising sand, sandy clay, etc., of Quaternary age underlain by a Tertiary sequence comprising alternating beds of clays and sandstones with bands of limestone and lignite. The sandstones are ferruginous, gritty and locally clayey. The clays are variegated. 0034-6667/95/$9.50© 1995ElsevierScienceB.V. All rights reserved SSDI 0034-6667 (94) 00137-5

The Nirkunnam bore-hole is located at a distance of 60 m southeast of Governament Porambaka land. The area is covered by coastal alluvium composed of sand and sandy clay. This is underlain by a sequence of alternating beds of clay and sandstone with thin bands of lignite and limestone. Palynological studies on the Tertiary sediments of Kerala have been performed by Vimal (1953), Potoni6 and Sah (1960), Ramanujam (1977, 1987), Rao and Ramanujam (1978, 1982), Kar and Jain (1981), Varma and Patil (1985), Varma et al. (1986), Raha et al. (1987), Varma (1987), and Rao (1990). The Tertiary sediments of the Kerala State extend all along its coastal region (Fig. 1). These sediments indicate two major basins of deposition,

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325 348

326

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2. Materials and methods

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Thirty-two samples from Kalarakod and 10 samples of Nirkunnam bore-holes were provided by Central Ground Water Board, Trivandrum, Kerala. Out of these, 17 samples from Kalarakod and 5 from Nirkunnam were productive. Samples were treated with HC1, HF and HNO3 followed by a 5% solution of KOH. The slides were prepared in polyvenyl alcohol and mounted in Canada Balsam. An Olympus BH2 microscope has been used for the study and photomicrography. The material, slides and negatives of figured specimens have been deposited in the museum of BSIP, Lucknow.

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3. Systematic description 9o

The palynomorph assemblages from Kalarakod and Nirkunnam bore-holes are compared in Table 1.

\ (P 6°

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00'

Genus Dictyophyllidites Couper, 1958 emend. Dettmann, 1963

Fig. 1. Localities o f Tertiary exposures in Kerala Basin.

Dictyophyllidites sp. (Plate I, 3) Occurrence: Nirkunnam bore-hole, 107 m depth, namely (1) a southern basin between Trivandrum and Ponnani in the south and central Kerala, and (2) a northern basin between Cannanore and Kasargad in north Kerala. The two basins mainly consist of (1) the Quilon Formation, characterised by fossiliferous limestone with intercalations of calcareous clays, and (2) the Warkalli Formation including variegated sandstone interbedded with white plastic and variegated clays, carbonaceous clays, sands and seams of lignite or peaty lignite (Poulose and Narayanaswami, 1968). A recent study of the lithology based on bore-hole information resulted in the institution of a third formation, namely the Vaikom Formation underlying the Quilon Formation. The Vaikom Formation resembles the Warkalli Formation but is more arenaceous and coarse-grained (Rao, 1975; Rao et al., 1975).

Alleppey district, Kerala. Affinity: ?Matoniaceae. Genus Osmundaeidites Couper, 1953

Osmundacidites sp. (Plate I, 13) Occurrence: Kalarakod bore-hole, 490 m depth, Alleppey district, Kerala. Affinity: Osmundaceae. Genus Lycopodiumsporites Thiergart ex Delcourt and Sprumont, 1955

Lycopodiumsporites sp. (Plate I, 5, 6) Occurrence: Kalarakod bore-hole, 447 m depth, Alleppey district, Kerala. Affinity: Lycopodiaceae.

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348

327

Table 1 Palynomorph assemblages from the Kalarakod and Nirkunnam bore-holes Name of palynotaxa

Kalarakod

Nirkunnam

Dinoflageilate cysts Achomosphaera sp. Operculodinium centrocarpum (Deflandre and Cookson, 1955) Wall, 1967 (Plate IV, 12) Thalassiphora pelagica (Eisenack) Eisenack and Gocht, 1960

+ + +

Pteridophyte spores Biretisporites meghalayaensis Rao and Singh, 1987 (Plate I, 9) Cheilanthoidspora monoleta Sah and Kar, 1974 (Plate I, 4) Crassoretitriletes vanraadshooveni Germeraad et al., 1968 (Plate I, 7) Dandotiaspora telonata (Sah et al) Singh et al., 1979 (Plate I, 11) Intrapunctisporis harudiensis Kar, 1979 Lygodiumsporites lakiensis Sah and Kar, 1969 (Plate I, 1) L. eocenicus Dutta and Sah, 1970 (Plate I, 12) L. padappakkarensis Rao and Ramanujam, 1978 Neyvelisporites bolkhovitinae Ramanujam, 1972 Polypodiaceaesporites major Saxena, 1978 Polypodiisporites favus Potoni6, 1934 P. tuberculensis (Baksi) Rao and Singh, 1987 P. speciosus Sah, 1967 Pteridacidites vermiverrucatus Sah, 1967 (Plate I, 8) Striatriletes susannae van der Hammen emend. Kar, 1979 (Plate I, 10) Todisporites major Couper, 1958 (Plate I, 2)

+ + + + + + + + + + + + + + +

Angiosperm pollen grains Anacolosidites luteoides Cookson and Pike, 1954 (Plate IV, 8) *Bacutriporites venkatachalae Rao, sp. nov. Chenopodipollis miocenica Kar and Jain, 1981 Clavaperiporitesjacobii Ramanujam, 1966 (Plate IV, 9) Compositoipollenites africanus Sah, 1967 C. minimus Ramanujam, 1987 *C. alleppeyensis Rao, sp. nov. (Plate III, 1-3) Ctenolophonidites costatus (van Hoeken Klinkenberg) van Hoeken Klinkenberg, 1966 (Plate IV, 1, 2) Dermatobrevicolporites dermatus (Sah and Kar) Kar, 1985 (Plate II, 9) Ericipites congoensis Sah, 1967 (Plate IV, 6, 7) Favitricolporites magnus Sah, 1967 lridacidites warkalliensis Ramanujam, 1987 (Plate IV, 11 ) Jacobipollenites arthungalensis Rao, 1990 Lakiapollis ovatus Venkatachala and Kar, 1969 Malvacearumpollis bakonyensis Nagy, 1964 M. grandis Sah, 1967 (Plate III, 13) Margocolporites tsukadae Ramanujam, 1966 (Plate III, 8) M. sitholeyi Ramanujam, 1966 (Plate III, 7) Meliapollis quadrangularis (Ramanujam) Sah and Kar, 1970 *Myricipites singhii Rao, sp. nov. Neocouperipollis kutchensis Kar and Kumar, 1987 (Plate III, 12) Ornatetradites chandae Rao and Ramanujam, 1982 *0. keralaensis Rao, sp. nov. Palmaepollenites kutchensis Venkatachala and Kar, 1969 P. keralensis Rao and Ramanijujam, 1978 (Plate IV, 13) Periretitricolpites anambraensis Jan Du Chene et al., 1978 (Plate III, 9) Polyporina multiporosa Kar and Jain, 1981 Proteacidites triangulus Kar and Jain, 1981 Quilonipollenites sahnii Rao and Ramanujam, 1978 (Plate II, 3)

+ ÷ + + + + + + + + + + + + + + + + + + + + + + + ÷ +

÷ + + ÷ ÷ ÷ ÷

+ +

328

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325 348

Table 1 (continued) Name of palynotaxa

Kalarakod

Retitriporites quilonensis Rao and Ramanujam, 1982 Sastriipollenites trilobatus Venkatachala and Kar, 1969 (Plate II, 11) Striacolporites striatus Sah and Kar, 1970 (Plate III, 6) Subtriporopollis rotundis Sah, 1967 Triangulorites bellus (Sah and Kar) Kar, 1985 (Plate II, 10) Tricolporopilites pseudoreticulatus Kar, 1985 (Plate II, 12, 13) Tricolporopollis matanamadhensis (Venkatachala and Kar) Tripathi and Singh, 1985 Tricolpites reticulatus Cookson ex Couper, 1953 72 crassireticulates Dutta and Sah, 1970 72 retibaculatus Saxena, 1979 72 matanomadhensis Saxena, 1979 T. retipilatus Kar and Jain, 1981 Triporopollenites robustus Kar and Jain, 1981 Trisyncolpites ramanujamii Kar, 1979 (Plate III, 5)

Nirkunnam +

+ + + + + + + + + + +

+

+

+ + +

+

Incertae sedis

* Verrualates kalarakodensis Rao, sp. nov. (Plate II, 1, 2)

+

Taxa with an asterisk mark are described in the text. G e n u s Retipollenites G o n z a l e z G u z m a n ,

1967

Retipollenites sp. ( P l a t e II, 4 ) Occurrence: K a l a r a k o d b o r e - h o l e , 388 m d e p t h ,

G e n u s Compositoipollenites P o t o n i 6 , 1951

Type

species:

Compositoipollenites

rizophorus

P o t o n i 6 , 1951

Alleppey district, Kerala.

Compositoipollenites alleppeyensis R a o , sp. nov.

Affinity: U n k n o w n .

( P l a t e III, 1 - 3 ) G e n u s Retitricolporites ( v a n d e r H a m m e n ) H a m m e n a n d W i j m s t r a , 1964

van der

Retitricolporites sp. ( P l a t e II, 6, 7 ) Occurrence: N i r k u n n a m b o r e - h o l e , 142 m d e p t h , Alleppey district, Kerala. Affinity: U n k n o w n

Holotype: P l a t e I I I , 1, 2, size 72 x 69 lam, slide N o . 10841, B S I P m u s e u m . T y p e locality: K a l a r a k o d b o r e - h o l e , A l l e p p e y district, K e r a l a , d e p t h r a n g e 2 1 . 7 5 - 2 5 . 7 5 m . Diagnosis and description: P o l l e n g r a i n s s u b c i r c u l a r i n s h a p e . Size r a n g e 7 2 - 9 0 x 6 5 - 7 2 ~tm ( i n c l u d i n g

PLATE 1 All photomicrographs enlarged c. × 500, unless otherwise stated. Coordinates of the specimens refers to the stage of the BH2 Olympus microscope No. 217267. 1. Lygodiumsporites lakiensis Sah and Kar, 1969. BSIP slide No. 10823, coordinates 21.5 x 149.0. 2. Todisporites major Couper, 1958. BSIP slide No. 10824, coordinates 9.0 x 130.0. 3. Dictyophyllidites sp. BSIP slide No. 10825, coordinates 7.0 x 170.0. 4. Cheilanthoidspora monoleta Sah and Kar, 1974. BSIP slide No. 10826, coordinates 12.0 x 126.0. 5, 6. Lycopodiumsporites sp. BSIP slide No. 10827, coordinates 21.5 × 149.0. 7. Crassoretitriletes vanraadshooveni Germeraad et al., 1968. BSIP slide No. 10828, coordinates 4.5 x 152.5. 8. Pteridacidites vermiverrucatus Sah, 1967. BSIP slide No. 10853, coordinates 19.0 x 163.0. 9. Biretisporites meghalayaensis Rao and Singh, 1987. BSIP slide No. 10861, coordinates 5.5 x 155.3. 10. Striatriletes susannae van der Hammen emend. Kar, 1979. BSIP slide No. 10828, coordinates 7.5 x 148.5. 11. Dandotiaspora telonata (Sah et al.) Singh et al., 1979. BSIP slide No. 10831, coordinates 16.5 x 167.0. 12. Lygodiumsporites eocenicus Dutta and Sah, 1970. BSIP slide No. 10830, coordinates 3.5 x 135.5. 13. Osmundacidites sp. BSIP slide No. 10832, coordinates 14.0 x 160.5.

M. R Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348

PLATE I

7

329

=iii

ii'L~!il

(

i¸

4~

I

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M.R. Rao/Reviewof Palaeobotanyand Palynology86 (1995) 325-348 spines). Tricolporate, zonaperturate, colpi not distinct due to thickening of annulus around pore. Pore distinct. Exine 2.5-3 Ixm thick, sexine and nexine not differentiated, intectate, spines sparsely placed, 4-6~tm long, 2 - 3 pan wide, 16 spines present, bacula present in between spines, bacula closely placed. Surface showing fine negative reticulum.

Comparison: Compositoipollenites alleppeyensis closely compares with all the general characters of C. rizophorus Potoni6 (1951) but is distinct in being larger and having thicker exine. C. alleppeyensis is distinct from C. africanus Sah (1967) in having its wide colpi, tectate exine and suprategillar spines. C. spinulosus Sah is different in having tectate and dense columellate structure. C. conicus Sah differs in having smaller in size (40-47 ~tm) and posses indistinct pores. C. variabilis Sah is different in having 25-30 spines along the exine, hence, not comparable. C. serratus Sah (1967) is distinct by the presence of small spinules (3 ~tm long). C. horridus Sah (1967) differs from the present species in having indistinct pore and blunt strong spiny processes. Occurrence: K a l a r a k o d bore-hole, 21.75-25.75 m depth, Alleppey district, Kerala. Affinity: Unknown. Genus Meliapollis Sah and K a r emend. Navale and Misra, 1979

Meliapollis sp. (Plate II, 14)

331

Occurrence: K a l a r a k o d bore-hole, 549 m depth, AUeppey district, Kerala. Affinity: ?Alangiaceae.

Genus Myricipites Wodehouse, 1933

Type species: Myricipites dubius Wodehouse, 1933

Myricipites singhii Rao, sp. nov. (Plate III, 10) Holotype: Plate Ill, 10, size 74 x 67 pm, slide No. 10836, BSIP museum. Type locality: K a l a r a k o d bore-hole, 374-377 m depth, Alleppey district, Kerala. Diagnosis and description: Pollen grains subtriangular-subcircular associated with folds. Size range 75-100 × 67-82 ktm. Triporate, pore distinct, 12-14 Ixm diameter. Exine 3 - 4 ~tm thick. Ornamentation psilate to scabrate. Comparison: Myricipites harrisii (Couper) Durra and Sah, 1970 is comparable with the present species by its triporate condition and nature of exine but latter is distinguished by having larger size (up to 100 ~tm) and thick exine ( 3 - 4 ~tm thick). Myricipites vulgaris D u t t a and Sah, 1970 is distinct by its smaller size and surface minutely granulate ornamentation. Occurrence: K a l a r a k o d bore-hole, 374-377 m depth, Alleppey district, Kerala. Affinity: Myricaceae

PLATE II 1,2.

Verrualetes kalarakodensis Rao, sp. nov. BSIP slide Nos. 10833, coordinates 12.5 × 171.0 (holotype); 10834, coordinates 10.0 × 151.0

3. Quilonipollenites sahnii Rao and Ramanujam, 1978. BSIP slide No. 10835, coordinates 4.5 × 163.0. 4. Retipollenites sp. BSIP slide No.10836, coordinates 17.0× 142.0. 5. Palmaepolleniteskutchensis Venkatachala and Kar, 1969. BSIP slide No. 10837, coordinates 12.5 x 155.0. 6, 7. Retitricolporites sp. BSIP slide No. 10838, coordinates 12.0 x 128.0. 8. Favitricolporitesmagnus Sah, 1967. BSIP slide No. 10839, coordinates 18.0 x 133.2. 9. Dermatobrevicolporites dermatus (Sah and Kar) Kar, 1985. BSIP slide No. 10839, coordinates 12.5 x 157.0. 10. Triangulorites bellus (Sah and Kar) Kar, 1985. BSIP slide No. 10832, coordinates 8.5 × 158.0. 11. Sastriipollenites trilobatus Venkatachala and Kar, 1969. BSIP slide No. 10832, coordinates 21.0 × 134.0. 12, 13. Tricolporopilitespseudoreticulatus Kar, 1985. BSIP slide Nos. 10832, coordinates 8.6 × 140.5.; 10830, coordinates 17.4 × 159.4. 14. Meliapollis sp. BSIP slide No. 10840, coordinates 3.0 × 157.0.

332

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348 P L A T E III

~

jiiiii[iiiiiiiiiiiii~iii~. ~,<~ii~i ¸ ¸

M.I~ Rao/Review of Palaeobotany and Palynology 86 (1995) 325 348

Genus Bacutriporites Jan du Chene et al., 1978

Type species: Bacutriporites orluensis Jan du Chene et al., 1978 Bacutriporites venkatachalae Rao, sp. nov. (Plate IV, 10) Holotype: Plate IV, 10, size 82 × 70 ~tm, slide No. 10854, BSIP museum Type locality: Kalarakod bore-hole, 374-377 m depth, Alleppey district, Kerala. Diagnosis and description: Pollen grains oval-subcircular in shape. Size range 65-82 × 56-70 ~ma. Triporate, pore 8 ~tm in diameter, surrounded by thick annulus. Exine 1-2.5 ~tm thick, baculate, bacula sparsely placed, 5-7 ~tm long, 2-3 I~m wide, in between bacula small spinules present, closely placed. Surface showing pitted microreticulate ornamentation. Comparison: The present species is closely comparable with the type species B. orluensis Jan du Chene et al., 1978, in all general characters but the latter is distinguished by its regularly spaced bacula with fine and densely spaced pilate sculpture in between. Occurrence: Kalarakod bore-hole, 374-377 m depth, Alleppey district, Kerala. Affinity: Unknown. Genus Ornatetradites Rao and Ramanujam, 1982

333

Ornatetradites keralaensis Rao, sp. nov. (Plate IV, 4,5)

Holotype: Plate IV, 5, size 62 × 60 ~tm, slide No. 10851, BSIP museum. Type locality: Kalarakod bore-hole, 295-298 m depth, Alleppey district, Kerala. Diagnosis and description: Pollen grains in tetrahedral tetrads. Size range 53-70 x 52-60 ~tm. Individual grains 32-43 × 22-38 ~tm. Porate, 4-6 pores, obscured by heavy sculptural elements. Exine 2-2.5 ~tm thick, sexine and nexine not differentiated, tectate, columella distinct, verrucate, verrucae 3-4 ~tm high, sparsely placed, surface in between verrucae finely reticulate. Comparison: Ornatetradites droseroides Rao and Ramanujam, 1982, is different from O. keralaensis by its smaller size range, gemmate-tuberculate ornamentation. Ornatetradites chandae Rao and Ramanujam, 1982, is closely comparable to the present species but the former is distinguished by its smaller size and surface between verrucae is psilate to finely punctate ornamentation. Occurrence: Kalarakod bore-hole, 295-298 m depth, Alleppey district, Kerala. Affinity: Droseraceae. Stephanocolporate type (Plate III, 4)

Occurrence: Nirkunnam bore-hole, 142 m depth, Alleppey district. Kerala.

Type species: Ornatetradites droseroides Rao and Ramanujam, 1982

PLATE III 1-3. Compositoipollenites alleppeyensis Rao, sp. nov. BSIP slide Nos. 10841, coordinates 13.5 x 165.0 (holotype); 10842, coordinates 8.6 x 153.7. 4. Stephanocolporate type. BSIP slide No. 10828, coordinates 21.0 x 155.0. 5. Trisyncolpites ramanujamii Kar, 1979. BSIP slide No. 10843, coordinates 19.0 x 134.0. 6. Striacolporites striatus Sah and Kar, 1970. BSIP slide No. 10844, coordinates 13.5 × 134.5. 7. Margocolporites sitholeyi Ramanujam, 1966. BSIP slide No. 10845, coordinates 13.3 x 154.0. 8. Margocolporites tsukadae Ramanujam, 1966. BSIP slide No. 10825, coordinates 20.5 x 144.0. 9. Periretitricolpites anambraensis Jan Du Chene et al., 1974. BSIP slide No. 10846, coordinates 21.0 x 125.3. 10. Myricipites singhii Rao, sp. nov. BSIP slide No. 10836, coordinates 13.5 x 156.5 (holotype). 11. Meliapollis quadrangularis (Ramanujam) Sah and Kar, 1970. BSIP slide No. 10830, coordinates 14.0 x 152.4. 12. NeocouperipoHis kutchensis Kar and Kumar, 1986. BSIP slide No. 10831, coordinates 19.5 x 150.0. x 750. 13. Malvacearumpollis grandis Sah. 1967. BSIP slide No. 10853 coordinates 14.0 x 142.0. x 750.

C~

\,

I ~J

B~

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348 INCERTAE SEDIS

Genus Vervualetes Singh and Saxena, 1984

Type species: Saxena, 1984

Verrualetes assamicus Singh and

Verrualetes kalavakodensis Rao, sp. nov. (Plate II, 1, 2) Holotype: P l a t e l I , 1, size 5 2 x 5 5 g m , slide No. 10833, BSIP museum Type locality: K a l a r a k o d bore-hole, Alleppey district, Kerala, depth range 21.75-25.75 m. Diagnosis and description: Pollen grains subcircular in shape. Size range 52-58 x 52-55 gin. Inaperturate. Exine 3 - 4 gm thick, ornamented by sparsely placed verrucae, 5-10~tm high, 5 - 6 g m wide. Ornamentation in between verrucae psilate to scabrate. Comparison: Verrualetes assamicus Singh and Saxena, 1984, is comparable in having inaperturate and verrucate ornamentation but can be distinguished from the present species in having larger and densely placed verrucae forming a pseudoreticulum in surface view. Occurrence: K a l a r a k o d bore-hole, 21.75-25.75 m depth, Alleppey district, Kerala. Affinity: Unknown.

4. Palynofloral analysis Palynofloral assemblages of the K a l a r a k o d and N i r k u n n a m bore-holes consist of dinoflagellate

335

cysts, fungal remains, pteridophyte spores and angiosperm pollen. G y m n o s p e r m o u s pollen were not encountered in the assemblage. The angiosperm pollen dominate over pteridophyte fern spores in both the bore-hole assemblages. The possible affinities of palynomorphs recognized in these assemblages and the present-day distribution of their families are given in Table 2. Palynomorphs recovered from K a l a r a k o d and N i r k u n n a m bore-holes have been assigned to 56 genera and 79 species of pteridophyte spores and angiosperm pollen. K a l a r a k o d assemblage consists of 14 genera and 18 species of pteridophyte spores and 35 genera and 44 species of angiosperm pollen. Verrualetes kalarakodensis, Compositoipollenites alleppeyensis, Myricipites singhii, Bacutriporites venkatachalae and Ornatetradites keralaensis are proposed as new species. Palynomorph percentages of the K a l a r a k o d assemblage are plotted in Fig. 2. The N i r k u n n a m p a l y n o m o r p h assemblage is represented by 9 genera and 14 species of pteridophytic spores and 22 genera and 25 species of angiosperm pollen. The percentages of 26 significant species are plotted in Fig. 3. On the basis of qualitative and quantitative analyses, the N i r k u n n a m bore-hole has been divided into three zones. Zone I of the bore-hole (264-196 m) is characterized by the presence of Lygodiumsporites padappakkarensis, Todisporites major, Crassoretitriletes vanraadshooveni, Lakiapollis ovatus, Tricolporopollis matanamadhensis and Ctenolophonidites costatus. The frequency of Ctenolophonidites costatus is low (2%). Polypodiaceaesporites major and Subtriporopollis rotundis are restricted

PLATE IV 1, 2. Ctenolophonidites costatus (van Hoeken-Klinkenberg) van Hoeken-Klinkenberg, 1966. BSIP slide No. 10826, coordinates 14.5 x 136.0. 3. Proteaciditestriangulus Kar and Jain, 1981. BSIP slide No. 10849, coordinates 5.0 x 153.0. 4, 5. Ornatetradites keralaensis Rao, sp. nov. BSIP slide Nos. 10850, coordinates, 8.0x 161.5., 10851, coordinates 8.0x 133.0 (holotype). 6, 7. Ericipitescongoensis Sah, 1967. BSIP slide No. 10828, coordinates 6.0 × 143.6. 8. Anacolosiditesluteoides Cookson and Pike, 1954. BSIP slide No. 10864, coordinates 17.0 × 132.5. × 750. 9. ClavaperiporitesjacobiiRamanujarn, 1966. BSIP slide No. 10856, coordinates 6.3 x 156.0. 10. Bacutriporitesvenkatachalae Rao, sp. nov. BSIP slide No. 10854, coordinates 14.0 x 130.5 (holotype). x 750. 11. Iridaciditeswarkalliensis Ramanujam, 1987. BSIP slide No. 10842, coordinates 8.5 x 159.0. 12. Operculodiniumcentrocarpum (Defiandre and Cookson, 1955) Wail, 1967. BSIP slide No. 10843, coordinates 18.5 x 144.0. 13. Palmaepolleniteskeralaensis Rao and Ramanujam, 1978. BSIP slide No. 10850, coordinates 14.0x 129.0.

336

M. R, Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348

PLATE V

~,2

,

k.

,o

5

M.R. Rao/Review o f Palaeobotany and Palynology 86 (1995) 325-348

to Zone I. Dominance of Striatriletes susannae,

Crassoretitriletes vanraadshooveni, Todisporites major and lntrapunctisporis harudiensis has been observed in Zone II (196-107 m) whereas the frequency of Lygodiumsporites padappakkarensis is low. Lakiapollis ovatus and Tricolporopollis matanamadhensis are also dominant in Zone II. Palmaepollenites kutchensis, Tricolpites reti-

pilatus, Margocolporites tsukadae, Favitricolporites magnus, Ericipites congoensis and Cheilanthoidspora monoleta are restricted to Zone II. The frequency of Malvacearumpollis bakonyensis is lower in Zone II and increases in Zone III. Striatriletes susannae dominates over Lygodium-

sporites padappakkarensis, Intrapunctisporis harudiensis and Todisporites major in Zone III (107-30 m). Lakiapollis ovatus and Tricolporopollis matanamadhensis are also dominant whereas Ctenolophonidites and Quilonipollenites disappear. Chenopodipollis miocenica, Malvacearumpollis grandis and Compositoipollenites minimus are restricted to this zone. The palynomorph assemblages from Kalarakod and Nirkunnam bore-holes are compared in Table I.

5. Palynostratigraphic zonation The zonation of the Kalarakod assemblage is based on palynomorph frequencies (Fig. 2). For the quantitative analysis, 150 specimens per sample were counted. However, in case of samples with poor yield only 100 specimens were counted. Percentage frequencies of all the species were calculated and plotted under four categories, namely rare (1-5%), common (6-10%), abundant (11-20%), and predominant (above 21%) (Fig. 4). Three cenozones were recognised in the Kalarakod bore-hole on the basis of palynomorph frequencies,

PLATE V All enlarged c. x 1000.

1. 2. 3. 4. 5.

Ornatetradites keralaensis Rao, sp. nov. Bacutriporites venkatachalae Rao, sp. nov. Compositoipollenites alleppeyensis Rao, sp. nov. Verrualetes kalarakodensis Rao, sp. nov. Myricipites singhii Rao, sp. nov.

337

namely the Triangulorites bellus Cenozone, the Crassoretitriletes vanraadshooveni Cenozone, and the Malvacearumpollis bakonyensis Cenozone (Fig. 4). Each cenozone has been formally instituted in accordance with the International Stratigraphic Guide (Hedberg, 1976).

5.1 Triangulorites bellus Cenozone The lithology of the cenozone is mainly composed of sandstone, clay and streaks of lignite and the thickness is 199 m. This cenozone overlies Upper Palaeocene sandstone and sandy clay which is unconformably overlain by the clay bed of the Crassoretitriletes vanraadshooveni Cenozone. The significant restricted taxa of this cenozone are: Dandotiaspora telonata, Retipollenites sp.,

Periretitricolpites anambraensis, Neocouperipollis kutchensis, Tricolpites reticulatus, Meliapollis quadrangularis, Tricolporopilites pseudoreticulatus, Triangulorites bellus, Sastriipollenites trilobatus, Striacolporites striatus, Triangulorites bellus, Cheilanthoidspora monoleta, and Tricolpites matanomadhensis are other significant species of this cenozone. The significant feature of this cenozone is the dominance of angiosperm pollen over pteridophytic spores. Neocouperipollis kutchensis is abundant (28%) in the lower part and absent in the upper part of the cenozone. Ctenolophonidites costatus, Margocolporites tsukadae and Lakiapollis ovatus are abundant throughout the cenozone.

5.2 Crassoretitriletes vanraadshooveni Cenozone This 164 m thick cenozone comprises clay, sandstone and a thin band of limestone. The upper part of the cenozone is composed of sandstone which is conformably overlain by the Malvacearumpollis bakonyensis Cenozone. The characteristic restricted taxa of this cenozone are

338

M . R . Rao/Review of Palaeobotany and Pulynology 86 (1995) 3 2 5 - 3 4 8

Table 2 Possible affinities of palynomorphs recognized in the assemblages and their present-day distribution Family

Taxa

Climate Tropical

Clusiaceae Ctenolophonaceae Olacaceae Proteaceae Arecaceae

Bombacaceae Caesalpiniaceae

Gunneraceae Moraceae Myricaceae Osmundaceae Parkeriaceae Schizaeaceae

Adiantaceae Asteraceae Droseraceae Ericaceae Euphorbiaceae Hymenophyllaceae Iridaceae Lycopodiaceae Malvaceae Polypodiaceae

Rubiaceae

Thymeliaceae Chenopodiaceae

Meliapollis quadrangularis Ctenolophonidites costatus Anacolosidites luteoides Proteacidites triangulus Palmaepollenites keralensis P. kutchensis Neocouperipollis kutchensis Quilonipollenites sahnii Lakiapollis ovatus Margocolporites tsukadae

+ 4+ 444+ + + +

M. sitholeyi

+

Trisyncolpites ramanujamii Tricolpites reticulatus Triporopollenites robustus Myrieipites singhii Osmundacidites sp. Striatriletes susannae Lygodiumsporites lakiensis L. eocenicus L.padappakkarensis Crassoretitriletes vanraadshooveni Neyvelisporites bolkhovitinae Todisporites major Pteridacidites vermiverrucatus Compositoipollenites africanus C. minimus Ornatetradites chandae O. keralaensis Ericipites congoensis Tricolporopollis matanamadhensis Biretisporites meghalayaensis lridacidites warkalliensis Lycopodiumsporites sp. Malvacearumpollis bakonyensis M. grandis Polypodiaceaesporites major Polypodiisporites favus P. tuberculensis P. speciosus Retitriporites quilonensis Subtriporopollis rotundis Favitricolporites magnus Clavaperiporites jacobii Chenopodipollis miocenica Polyporina multiporosa

+ 4. + +

+ 4+ 4+ 4+ 4+ + + + + 4+ + +

+ + 4+ +

4+

4+

4+

Subtropical

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Trisyncolpites ramanujamii, Bacutriporites venkatachalae and Ornatetradites keralaensis. Margocolporites tsukadae and Ericipites congoensis are also

ovatus (15%) and Ctenolophonidites costatus (15%)

significant species of this cenozone. The appearence of Crassoretitriletes vanraadshooveni and Trisyncolpites ramanujamii is significant in this cenozone. Lygodiumsporites padappakkarensis is c o m m o n in the lower part (5%) and abundant (15%) at the top of the cenozone. Lakiapollis

5.3 Malvacearumpollis bakonyensis Cenozone

are predominant taxa in this cenozone.

The lithology of the cenozone comprises sandstone with traces of white clay, sand intercalated with grey clay and fine-grained sand mixed with ilmenite and glass sand. The Malvacearumpollis

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348

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bakonyensis C e n o z o n e is overlain by sand devoid o f palynofossils. The important restricted taxa o f this c e n o z o n e are Pteridacidites vermiverrucatus,

Compositoipollenites alleppeyensis, Chenopodipollis mioeenica, Malvacearumpollis bakonyensis and M. grandis. Striatriletes susannae and Quilonipollenites sahnii are also significant species of this cenozone. Pteridophytic spores are dominant over angio-

sperm pollen. Striatriletes susannae (35%) is a predominant taxon. The relative increase o f Crassoretitriletes vanraadshooveni and Quilonipollenites sahnii has been observed whereas Lakiapollis ovatus and Tricolporopllis matanamadhensis are rare and c o m m o n at the upper part of the cenozone. Ctenolophonidites costatus is absent in this cenozone.

M.R. Rao/Review oJ'Palaeobotany and Palynology 86 (1995) 325 348

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M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348

6. Palynostratigraphic correlation

343

Quilonipollenites sahnii, Chenopodipollis miocenica Compositoipollenites alleppeyensis. Except Pteridacidites vermiverrucatus, the assemblages of the top Malvacearumpollis bakonyensis Cenozone and

Palynostratigraphic correlation of different bore-holes of the Alleppey district, Kerala is presented in Fig. 5. The Kalarakod bore-hole has the thickest strata among the two bore-holes and is represented by three cenozones, namely the Triangulorites bellus Cenozone, the Crassoretitriletes vanraadshooveni Cenozone, and the Malvacearumpollis bakonyensis Cenozone. These cenozones are correlated with the standard reference section (Arthungal bore-hole). Rao (1990) studied the palynostratigraphy of the Arthungal bore-hole in the Alleppey district and recognised three palynozones, namely the Triangulorites bellus Cenozone, the Crassoretitriletes vanraadshooveni Cenozone, and the Malvacearumpollis bakonyensis Cenozone. The lowermost Triangulorites bellus Cenozone of the Kalarakod bore-hole is characterised by the presence of Dandotiaspora telonata, Cheilanthoid-

spora monoleta, Neocouperipollis kutchensis, Sastriipollenites trilobatus, Triangulorites bellus, Striacolporites striatus, Meliapollis quadrangularis, Lakiapollis ovatus, Ctenolophonidites costatus, Tricolpites reticulatus, Tricolporopollis matanamadhensis, Periretitricolpites anambraensis and Anacolosidites luteoides. A comparison of the present Triangulorites bellus Cenozone with the Triangulorites bellus Cenozone of the Arthungal bore-hole reveals that both assemblages are more or less the same except for the presence of Periretitricolpites anambraensis, Anacolosidites luteoides and Dandotiaspora telonata in the Kalarakod bore-hole. The middle cenozone of the Kalarakod bore-hole, the Crassoretitriletes vanraadshooveni Cenozone, contains Crassoretitriletes vanraadshooveni, L ygodium-

sporites padappakkarensis, Polypodiisporites speciosus, Trisyncolpites ramanujamii, Margocolporites tsukadae, Lakiapollis ovatus and Ctenolophonidites costatus. A comparison of the Crassoretitriletes vanraadshooveni Cenozone with the Arthungul bore-hole shows that both the assemblages are homotaxial. Lakiapollis ovatus and Ctenolophonidites costatus are dominant in both cenozones. The uppermost Malvacearumpollis bakonyensis Cenozone of the Kalarakod bore-hole consists of Striatriletes susannae, Crassoretitriletes

vanraadshooveni,

Pteridacidites vermiverrucatus,

of Kalarakod bore-hole and Arthungal bore-hole are the same.

7. Palaeoclimate

The Kalarakod and Nirkunnam assemblages consist of palynoflora having affinities with 26 extant families. Of these, 9 families are restricted to tropical-subtropical climates, 12 families are cosmopolitan, 4 families are restricted to the tropics and one family is temperate (Table 2). The presence of spore-pollen of Schizaeaceae, Parkeriaceae, Osmundaceae, Adiantaceae, Polypodiaceae, Caesalpiniaceae, Clusiaceae, Ctenolophonaceae, Oleaceae and Rubiaceae in the assemblage indicates that the tropical climate prevailed at the time of deposition. Fern spores and the occurrence of tropical rain forest elements (Ctenolophonaceae, Oleaceae, Proteaceae and Moraceae) support a climate with a high rainfall.

8. Environment of deposition

Different ecologocal groups such as montane, lowland, freshwater swamp and water-edge, backmangrove and sandy beach elements are represented in the assemblages of the two bore-holes. The frequencies of the following ecological groups of Kalarakod bore-hole have been given in Fig. 6. Montane elements

Clavaperiporites jacobii Ericipites congoensis Proteacidites triangulus

Thymeleaceae Ericaceae Proteaceae

Low-land elements

Favitricolporites magnus Subtriporopollis rotundis Margocolporites tsukadae Trisyncolpites ramanujamii Lakiapollis ovatus

Rubiaceae Apocynaceae Caesalpiniaceae Caesalpiniaceae Bombacaceae

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325-348

344

p 80 70

0

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.

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.

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.

15

.

16

.

[

18

27

28

29

30

31

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Fig. 6. Representation of different ecological groups in the Kalarakod bore-hole.

Tricolporopollis matanamadhensis Freshwater swamp and water-edge elements L ygodiumsporites padappakkarensis Crassoretitriletes vanraadshooveni Neyvelisporites bolkhovitinae Osmundacidites sp. Pteridacidites vermiverruca-

Euphorbiaceae

Schizaeaceae Schizaeaceae Schizaeaceae Osmundaceae Adiantaceae

tus

L ycopodiumsporites sp. Striatriletes susannae Polypodiaceaesporites major Polypodiisporites favus Ctenolophonidites costatus Meliapollis quadrangularis Anacolosidites luteoides Chenopodipollis miocenica Ornatetradites keralaensis Back-mangrove elements Malvacearumpollis bakonyensis M. grandis

Lycopodiaceae Parkeriaceae Polypodiaceae Polypodiaceae Ctenolophonaceae Clusiaceae Olacaceae Chenopodiaceae Droseraceae

Malvaceae Malvaceae

Sandy beach elements Palmaepollenites keralensis Quilonipollenites sahnii Neocouperipollis kutchensis

Arecaceae Arecaceae Arecaceae

The ecological groups of the Kalarakod borehole show that freshwater swamp and water-edge elements are dominant over the low-land elements. The frequency of montane elements is very low and present only in sample 6-13 and sample 14-16. Sandy beach elements dominate in the lower part (sample 3 7) and gradually decreases at sample 7 11 followed by an increase at sample 11-15 and then again decrease at the top. The frequency of freshwater swamp and water-edge elements is low in the lower part (sample 3-10) and increases at the top. The percentage frequency of low-land elements is very high in the lower part and gradually decreases towards the top. Back-mangrove elements have a very low frequency in the lower part (sample 3-9), disappear in the middle, and reappear at sample 16 dominating at the top. Dinoflagellate cysts are not shown in the ecological groups but are present in the lower part of the bore-hole, absent in the middle part and again present at the top. The ecological diagram (Fig. 6) indicates that the deposition of the Kalarakod bore-hole sediments took place in a cycle of slightly transgressive, regressive and transgressive phases.

M.1L Rao/Reviewof PalaeobotanyandPalynology86 (1995) 325-348 The presence of Lygodiumsporites padappakkar-

ensis, Todisporites major, Pteridacidites vermiverrucatus, Polypodiisporites favus, P. speciosus and Polypodiaceaesporites major in the Kalarakod and Nirkunnam assemblages indicates a freshwater swampy environment. The montane elements of the families Thymeleaceae, Ericaceae and Proteaceae may have derived from long distance. The presence of Droseraceae is indicative of freshwater lakes or ponds in the proximity. The coastal conditions are supported by the presence of palm pollen (Palmaepollenites keralensis, Neocouperipollis kutchensis and Quilonipollenites sahnii). The presence of dinoflagellate cysts (Operculodinium

centrocarpum, Thallasiphora pelagica, Achomosphaera sp.) and back-mangrove elements suggest the existence of brackish mangrove swamps. Pollen taxa comparable to Chenopodiaceae show a halophytic environment

9. Age of Kalarakod sediments On the basis of foraminifera, ostracods and molluscs, the Quilon Formation is assigned an Early-Middle Miocene age (Jacob and Sastri, 1952). The Warkalli Formation is considered to be late Miocene-Pliocene in age (Poulose and Narayanaswami, 1968). Raha et al. (1987)studied the Ambalapuzha bore-hole, in the Alleppey district, Kerala and suggested an Eocene-Early Miocene age for the sediments. The palynomorph taxa Proxapertites microreticulatus, Polycolpites,

Meliapollis ramanujamii, M. quadrangularis, Proteaeidites triangulus, Striaeolporites cephalus together with some palm pollen indicate an Eocene age. Oligocene age was inferred by the presence of

Crassoretitriletes vanraadshooveni, Trisyneolpites ramanujamii and Bombacacidites. The occurrence of Malvacearumpollis, Hibisceaepollenites splendus and Quilonipollenites are indicative of an Early Miocene age. A recent palynological study of the Arthungal bore-hole, Alleppey district, Kerala (Rao, 1990) also provides cogent evidence that the palynoflora varies from an Eocene to a Lower Miocene age. Ranges of significant palynomorphs from Indian Eocene-Miocene strata determined by various authors are given in Table 3.

345

The samples from depths 521-322 m exhibit the restricted range of Dandotiaspora telonata, Cheilanthoidspora monoleta, Retipollenites sp.,

Periretitricolpites anambraensis, Neocouperipollis kutchensis, Tricolpites reticulatus, Meliapollis quadrangularis, Tricolporopilites pseudoreticulatus, Triangulorites bellus, Sastriipollenites trilobatus, Striacolporites striatus, Lakiapollis ovatus, Ctenolophonidites costatus, Tricolporopollis matanamadhensis and Anacolosidites luteoides. Of these, Retipollenites sp., Periretitricolpites anambraensis, Neocouperipollis kutchensis, Trieolpites reticulatus, Triangulorites bellus, Tricolporopilites pseudoreticulatus, Sastriipollenites trilobatus and Anaeolosidites luteoides are markers for the Eocene (Table 3). Venkatachala et al. (1989) discussed the distribution of different Palaeocene-Eocene marker palynotaxa in India and Africa. According to them, the genus Lakiapollis, having an affinity to modern pollen of Durio, is found in Palaeocene-Eocene strata of Meghalaya, Kutch, Kerala and Assam. Post-Eocene occurrences of this pollen have not been recorded. Hence, the presence of Lakiapollis,

Ctenolophonidites, Tricolpites reticulatus, Retipollenites, Neocouperipollis, Tricolporopilites, Triangulorites and Anacolosidites in the above interval indicates an Eocene age. The Crassoretitriletes vanraadshooveni Cenozone extends from a depth of 322-158 m. Germeraad et al. (1968) critically studied the occurrence pattern of Crassoretitriletes in pantropical areas and suggested that the genus generally occurs in the lower Oligocene and extends upto the Miocene. Trisyncolpites recovered from Oligocene sediments of Kutch is considered as age definitive (Kar, 1979). The first appearence of Trisyneolpites ramanujamii and Crassoretitriletes vanraadshooveni intermixed with Polypodiisporites speciosus, Lygodiumsporites padappakkarensis, and Margocolporites tsukadae suggests an Oligocene age (Table 3).

Pteridacidites vermiverrucatus, Malvacearumpollis bakonyensis, Compositoipollenites alleppeyensis and Chenopodipollis miocenica are important genera recovered from a depth of 158-22 m. Malvacearumpollis is indicative of Early Miocene. It is also a dominant element in Khari Nadi Formation, Kutch (Kar, 1985), Surma Group, Meghalaya and Assam (Rao et al., 1985) but it is

346

M.R. Rao/Review of Palaeobotany and Palynology 86 (1995) 325 348

Table 3 Ranges of significant palynomorphs from Indian Eocene-Miocene strata Taxa

Age Eocene

References Oligocene Miocene

Cheilanthoidspora monoleta Neocouperipollis kutchensis Periretitricolpites anambraensis Retipollenites confusus Sastriipollenites trilobatus Striacolporites striatus Triangulorites bellus Tricolpites reticulatus Tricolporopilites pseudoreticulatus Tricolporopollis matanamadhensis Chenopodipollis miocenica Clavaperiporites jacobii Compositoipollenites africanus C. minimus Ericipites congoensis Iridacidites warkalliensis Malvacearumpollis bakonyensis M. grandis Neyvelisporites bolkhovitinae Ornatetradites chandae Proteacidites triangulus Pteridacidites vermiverrucatus Quilonipollenites sahnii Crassoretitriletes vanraadshooveni Trisyncolpites ramanujamii Anacolosidites luteoides

+ + + + + + + + + +

Ctenolophonidites costatus

+

+

+

Lakiapollis ovatus Margocolporites sitholeyi Margocoloporites tsukadae Meliapollis quadrangularis

+ + + +

+ + + +

+ + + +

4-

poorly represented in the K e r a l a Basin. Pteridacidites a n d Compositoipollenites have been recovered from the M i o c e n e sediments o f Rusizi Valley, B u r u n d i (Sah, 1967). T h u s the presence of Pteridacidites, M a l v a c e a r u m p o l l i s , Compositoipollenites, Chenopodipollis a n d the presence o f d o m i n a n t elem e n t s such as Striatriletes a n d Quilonipollenites at this depth indicates a n Early M i o c e n e age (Table 3 ). So, o u t of the total thickness of 610 m analysed in this deep bore-hole, the Eocene strata extend from a d e p t h o f 521 to 322 m. Based on palynological evidence, the Oligocene strata extend from 322

Sah and Kar, 1974 Kar and Kumar, 1987 Jan Du Chene et al., 1978 Gonzalez Guzman, 1967 Venkatachala and Kar, 1969 Kar, 1978, 1985 Kar, 1985; Rao, 1990 Kar, 1985; Saxena and Misra, 1990 Kar, 1985 (Venkatachala and Kar) Tripathi and Singh, 1985 Kar and Jain, 1981 Ramanujam, 1966; Rao and Ramanujam, 1982 Sah, 1967 Ramanujam, 1987 Sah, 1967 Ramanujam, 1987 Nagy, 1964 Sah, 1967 Ramanujam, 1972, 1987 Rao and Ramanujam,1982 Kar and Jain, 1981 Sah, 1967 Rao and Ramanujam,1978 Germeraad et al., 1968 Kar, 1979 Venkatachala and Rawat, 1972; Stover and Patridge, 1973 Rawat et al., 1977; Rao and Ramanujam, 1982; Rao, 1990 Sah and Kar, 1974; Kar, 1978, 1985; Rao, 1990 Ramanujam, 1966; Sah and Kar, 1974 Kar, 1985; Rao and Ramanujam, 1982 Kar, 1978, 1985; Navale and Misra, 1979

to 158 m a n d O l i g o c e n e - L o w e r Miocene appears to be r a n g i n g from 158 to 22 m. The M i o c e n e Oligocene b o u n d a r y m a y lie between 158 a n d 148 m.

10. Conclusions (1) The p a l y n o m o r p h assemblages in the K a l a r a k o d bore-hole can be divided into three cenozones, n a m e l y the Triangulorites bellus Cenozone, the Crassoretitriletes vanraadshooveni

M. P~ Rao/Review of Palaeobotany and Palynology 86 (1995) 325 348 C e n o z o n e , a n d the Malvacearumpollis bakonyensis C e n o z o n e . (2) A c o r r e l a t i o n of the K a l a r a k o d bore-hole was p e r f o r m e d with the A r t h u n g a l bore-hole, situated a p p r o x i m a t e l y 25 k m n o r t h w a r d s . (3) The p a l y n o f l o r a indicates a h u m i d a n d tropical climate with p l e n t y of rainfall d u r i n g the deposition of these sediments. (4) T h e d e p o s i t i o n t o o k place in a n e a r - s h o r e e n v i r o n m e n t with sufficient freshwater or freshwater swamps or both. (5) O n the basis o f palynological data, the sequence studied has been assigned a n Eocene to Early M i o c e n e age.

Acknowledgements I sincerely express m y gratitude to Dr. B.S. Venkatachala, former Director, Birbal Sahni Institute o f P a l a e o b o t a n y , L u c k n o w for c o n s t a n t e n c o u r a g e m e n t a n d suggestions. T h e a u t h o r is grateful to Drs. R . K . Saxena, Assistant D i r e c t o r a n d S.K.M. Tripathi, Senior Scientific officer, BSIP, L u c k n o w for k i n d l y going t h r o u g h the m a n u s c r i p t a n d giving valuable suggestions. The a u t h o r is t h a n k f u l to the Director, C e n t r a l G r o u n d W a t e r Board, T r i v a n d r u m for p r o v i d i n g bore-hole samples.

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