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Fossil pollen of Alangium from the eocene lignite of gujarat, India, with comments on its stratigraphic antiquity
Review (~f Palaeobotany and Palynology, 63 (1990): 281 297 Elsevier Science Publishers B.V., Amsterdam
28 l
Printed in The Netherlands
Fossil pollen of Alangium from the Eocene lignite of Gujarat, India, with comments on its stratigraphic antiquity N.R. Phadtare and B a n d a n a T h a k u r Palynology Laboratory, Wadia Institute o[ Himalayan Geology, Dehradun 248001 (India)
(Received May 17, 1989; revised and accepted March 7, 1990)
ABSTRACT Phadtare, N.R. and Thakur, B., 1990. Fossil pollen of Alangium from the Eocene lignite of Gujarat, India, with comments on its stratigraphic antiquity. Rev. Palaeobot. Palynol., 63: 281--297. Palynological studies on the Rajpardi lignite of Gujarat have yielded plentiful pollen grains closely comparable to those of extant Alangium Lamarck. These palynomorphs have been described under five different species of Lanagiopollis Morley (L. microrugulatus Morley, L. emarginatus Morley, L. ruguloreticulatus sp. nov., L. reitsmae sp. nov. and L. rugulatus sp. nov.) and Pellicieroipollis langenheimii Sah and Kar. The characteristic palynoflora of the Rajpardi lignite, as compared with those from other Tertiary deposits of India, indicates that this deposit of the Tarkeswar Formation is most probably of Early to Middle Eocene age. Detailed appraisal of the available Indian literature on fossil Alangium indicates that the section Marlea possibly existed in India during the Late Paleocene. Subsequently, during the Eocene it was accompanied by members of the section Conostigma. The section Alangium, however, appeared later, sometime during the Miocene.
Introduction
Existing and available records of fossil plant remains convincingly resembling modern Alangium are represented by wood (Awasthi, 1968), leaves (Wolfe and Tanai, 1980; Dalvi and Kulkarni, 1982), fruits (Eyde et al., 1969 and references therein) and a number of pollen grains (Muller, 1981; Morley, 1982; Phadtare and Kulkarni, 1983 and Thakur and Phadtare, 1989). The intercontinental as well as long-ranging temporal distribution of this fossil record clearly indicates that, although at present Alangium is confined to Africa and S.E. Asia, during the Mid-Tertiary period it had a pantropical distribution. In spite of the peculiar pollen morphological features (Reitsma, 1970; Morley, 1982) of this monogeneric family, that are well reflected also in the fossil record, its stratigraphic significance is still a matter for discussion. Remains of Alangium are well documented in 0034-6667/90/$03.50
c,~~) 1990 Elsevier Science Publishers B.V.
different Tertiary exposures in India. In this communication an attempt is made to describe some additional palynomorphs resembling those of extant Alangium. They have been recovered from a new Tertiary exposure of the Rajpardi lignite (Tarkeswar Formation, Table I) in southcentral Gujarat (Fig. 1). A critical review of existing literature on fossil remains of Alangium from different Tertiary exposures in India and a discussion of its stratigraphic antiquity are also presented. The Rajpardi lignite mine is a few kilometers away from Ankleswar and very close to the eastern margin of the South Cambay Basin. The detailed geology of the Jhagadia Tarkeswar area has been discussed by many workers (Bose, 1908; Sudhakar and Roy, 1959; Kathiara, 1968; Gadekar, 1975, 1977 and many unpublished reports of the ONGC (Oil and Natural Gas Commission). A more than 2000 m thick sequence of Tertiary sediments exposed for a small stretch around the
282
N.R. PHADTAREAND B. THAKUR
TABLE I Stratigraphy of the area (After G.M.D.C., 1983 and Kathiara, 1968) Age Quartenary
Recent Pleistocene
Tertiary
Pliocene Miocene
Formation
Lithology
Alluvium
Varied coloured sand, soil and Kankars
Jhagadia Formation
Light-coloured sandstone marls, limestone and conglomerate
Kand Formation
Limestone marls and clay with sandstone, sand and agate-bearing conglomorate
Babaguru Formation
Ferruginous sandstone, agate-bearing conglomorate and varied clay, gray sandstone and white sand
U M
Oligocene
Eocene
Gray, yellow, brown friable sandston with clay lenses. I
Tarkeshwar Formation
Bentonitic clays with lignite bed and lenses of I carbonaceous clay, sandstone and lignite II
U M
Nummulitic Formation
Nummulitic limestone, clay with sandstone lenses
L
Vagadkhol Formation
Bentonitic clays, friable sandstone and conglomerate
U L
D. Traps
Basalts with basic intrusions
Paleocene Cretaceous
Dashed block marks the sampling strata.
Jhagadia-Tarkeswar area unconformably overlies the Deccan Traps. The lowermost post-trappean sediments, equivalent to the Olpad Formation (Paleocene) of the Cambay Basin, are of the Vagadkhol Formation. In the Jhagadia area, the latter formation is unconformably overlain by the Nummulitic limestone of the Late Eocene (Chandra and Chowdhary, 1969). On the eastern side of Jhagadia, around Bhuri village where the lignite is being mined, the "Nummulitics" are, however, absent (Kathiara, 1968; Gadekar, 1977). Therefore, in the mining area the Vagadkhol Formation is unconformably overlain by the clay and lignite of the Tarkeswar Formation (Table I). The younger stratigraphic sequence above the Tarkeswar Formation (i.e., the Baba Guru Formation--*Kand Formation--*Jhagadia Formation, etc.) is similar to that of the Cambay Basin (Chandra and Chowdhary, 1969; Desikachar, 1984). The lignite samples processed for this study come from the lower part of the Tarkeswar Formation.
Material and methods
During two field visits to this mine, lignite samples were collected from measured vertical profiles (Fig. 1). The slandard conventional laboratory techniques (concentrated HNO 3 and 10% KOH treatments) were followed for recovery of microfossils from systematically cataloged and airdried samples. After chemical treatments, the recovered organic residue was subjected to ultrasonic sieving (100 jam and 10 jam sieves) to remove undesired particles and to increase microfossil concentration. Afater preparing 20 slides for optical microscopy, the remaining residue of each processed sample was treated with water: alcohol and alcohol: acetone grades, mounted on stubs, oven dried (60°C), coated with gold palladium (100A 125A) and scanned under a Philips 515 SEM microscope. Each recovered palynomorph resembling the extant Alangium has been described systematically,
283
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following the terminologies of Erdtman (1952) and Moore and Webb (1978). The description of each morphotype is based mainly on the optical illustrations. Nomenclaturai considerations
The fossil pollen grains resembling those found in extant Alangium Lamarck are classified under different form-genera. This nomenclatural ambiguity has already been discussed in detail by Morley (1982) and Kar (1985). Knowing the morphologic variability exhibited by extant Alangium pollen (Yeramyan, 1967; Eyde et al., 1969; Reitsma, 1970), a minimum of four form-genera is required
to adequately encompass the range of diversit' observed in fossil Alangium pollen. The generic diagnosis of Alangiopollis Krutzscl (1962) as emended by Morley (1982), accomodate the alangiaceous fossil palynomorphs having th striato-reticulate type of ornamentation. Similarl) another form-genus, Lanagiopollis Morley (1982 incorporates only eureticulate to eurugulate polle specimens. Pollen grains resembling those c modern Alangium are also found in species c several other morphographic genera such as Pell cieroipollis langenheimii Sah and Kar (1969 Margocolporites dubius Ramanujam and M. con plexum Ramanujam (1966), Ghoshiadites reticuh tus Nandi (1981), Foveotricolporites foveolan
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Nandi (1981), Tricolporipilites robustus (Kar and Saxena) Kar (1985) and Palaeoalangiumpollis zoniporatus Phadtare and Kulkarni (1983), etc. To avoid nomenclatural confusion, the palynomorphs here illustrated are described under existing appropriate form-genera. The nomenclatural revision of all the known fossil palynomorphs comparable to modern Alangium pollen is a taxonomic aspect and will be dealt with separately.
Pollen description Form-genus: Pellicieroipoilis Sah and Kar 1969 Pellicieroipollis Sah and Kar, p.133, plate 2, fig.58, Slide No. BSIP-3377. Emended diagnosis: Pollen grains large, oblate, triangular to sub-triangular in polar view, tricolporate, rarely di- or tetracolporate, generally brevicolpate; ora costate, distinctly lalongate; exine thick, mesocolpial nexine slightly thicker than sexine; ornamentation reticulate, generally homobrochate, often heterobrochate, muri simple- to duplibaculate.
Type species: Pellicieroipollis langenheimii Sah and Kar.
Holotype: Sah and Kar, 1969; pl.2, fig.58 Slide No. BSIP-3377.
Revised description: Pollen grain large (59 lain in equatorial diameter), oblate, isopolar, rounded triangular in polar view, tricolporate, brevicolpate; colpi tenuimarginate, margin straight, bordered with _+ elongated and slightly radiating brochi, ends acute; ora clearly costate, about 10 p.m wide, lalongate; mesocolpial nexine slightly thicker than sexine, ornamentation clearly reticulate. Remarks: The type material of Pellicieroipollis langenheimii Sah and Kar (1969) deposited in the repository of the Birbal Sahni Institute of Paleobo-
N R . P H A D T A R E A N D B. T H A K U R
tany, Lucknow, India (Slide Nos.3359, 3376 to 3380) was re-examined in view of the doubts raised by Muller (1981) and subsequently supported by Morley (1982), suggesting the possibility of its alangiaceous affinity. The revised morphological observations of the type species of this genus indicate its close resemblance to pollen of extant Alangium, particularly to that of the section Conostigma.
Pellicieroipollis langehheimii Sah and Kar (Plate I, 1-6). Description: Pollen grains large, 50 75jam in equatorial diameter, isopolar, triangular to subtriangular in polar view, angulaperturate, tri(rarely tetra) colporate. Colpi crassimarginate, distinctly brevicolpate, slightly fossaperturate, narrow, 6-10 gm wide along equator, ends acute; margins distinct, straight, bordered with thin to moderately thick margo or in some cases a row of minute brochi. Endoaperture clearly orate, ora circular to transversely elliptic, 8-12 tam in width, lalongate, distinctly costate, margin slightly incurved. Nexine slightly thicker than sexine along the mesocolpial region, whereas along endoapertures it is much thicker (5 tam). Sexine distinctly reticulate, reticulum generally homobrochate, often heterobrochate. When heterobrochate, the smaller, slightly elongated and radiating brochi are present around colpal ends, apocolpial brochi are medium and + sub-angular while those in mesocolpial area are bigger and polygonal. Specimens observed: More than 100. Variability: The examined specimens show marked variation in size ranging from 42 ~tm to 75 lain. To some extent the nature of the margin and width and length of colpi are also variable but within the circumscription of the species diagnosis. Comments: The above illustrated and described pollen is very similar to that of the Alangium ebenaceum Harms type (=A.javanicum (Blume) Wangerin of Reitsma, 1970) of the section Conos-
PLATE I
1 3. PellicieroipollislangenheimiiSah and Kar. 4. Obliqueequatorial viewof the similar pollen showingcircular, lalongate and costate ora. 5,6. SEM photograph of the similar pollen.
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FOSSIL POLLEN OF ALANG1UM
tigma. It is also very closely comparable with the following fossil pollen specimen. 1981 Ghoshiadites reticulatus Nandi in Nandi, 1981, p.33, pl.2, fig.47 1984 Ghoshiadites reticulatus Nandi in Thanikaimoni et al., 1984; pl.46, figs.643 646 1981 Foviotricolporitesfoveolatus Nandi in Nandi, 1981; p.33, pl.2 fig.45. 1984 Foveotricolporites foveolatus Nandi in Thanikaimoni et
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Comments: In general features, these pollen grains very closely resemble L. microrugulatus described by Moreley (1982) from Late-Eocene deposits of Central Java. A slight variation is, however, observed in the size of rugulae. The holotype is very finely eurugulate whereas the above-described specimen has slightly coarser ornamentation. The morphological features of this pollen suggest its affinity with the A. ebenaceum type of the section Conostigma (Morley, 1982).
al., 1984; pl.46, figs.638-642.
Form-genus: Lanagiopollis Morley Type Species: L. regularis Morley Holotype: Morley, 1982, pl. I, figs.3,4; Slide No. PW 1313-2. Generic diagnosis: Pollen grains large (60-105 lam), oblate, radially symmetrical, tricolporate or (rarely) ? di or tetracolporate, nexine thinner or thicker than sexine, often showing distinct thinning toward apertures; exine regularly or irregularly eureticulate or eurugulate; muri simplibaculate to pluribaculate. Lanagiopollis microrugulatus Morley, 1982 (Plate ll, 1 4) Description: Pollen grains large, oblate, isopolar, tricolporate, rounded triangular, angulaperturate, 55-70 lam in equatorial diameter; colpi tenuimarginate, 12-15 ~tm long, almost brevicolpate, fossaperturate, narrow, 8 10 lam wide at equator, ends acute, margins almost straight, smooth and bordered by radiating rows of rugulae. Endoaperture distinctly orate, ora circular to elliptic, 10-13 ~tm wide, clearly lalongate, costate, margin slightly incurved. Mesocolpial nexine characteristically thicker than sexine and thinning towards aperture, sexine (1.5 lam) thicker in mesocolpia and slightly thinning towards aperture, clearly microrugulate, simplibaculate.
PLATE II I 3. Lanagiopollis microrugulatus Morley. Slide No. Lig.-9/1 (S). 4. SEM photograph of the similar pollen. 5,6. Lanagiopollis emarginatus Morley. Slide No. Lig.-9/8 (S).
Lanagiopollis emarginatus Morley, 1982 (Plate II, 5,6) Description: Pollen grains large, isopolar, oblate, circular in polar view, tricolporate, planaperturate, 45 65 I~m in equatorial diameter: distinctly brevicolpate. Colpi characteristically tenuimarginate, inconspicuous, 7-10 p,m wide at equator, margins smooth, straight, beset with slightly smaller brochi. Endoaperture conspicuous, distinctly orate, ora circular to slightly elliptic, lalongate, about 10 I~m in diameter, costate; costae ca 3 lain thick, slightly incurved. Nexine imperceptibly thicker than sexine, thinning towards aperture; sexine eureticulate, mesocolpial columellae larger than those towards the apertures, almost homobrochate and simplibaculate. Comments: This palynomorph has previously been reported only from the Mio Pliocene of Malesia (Morley 1982). The present record indicates that, at least in the Indian subcontinent, the age of L. emarginatus can certainly be extended back to the Middle Eocene. It closely resembles pollen of A. havilandii Bloembergen (Morley, 1982). Lanagiopollis ruguloreticulatus sp. nov. (Plate IIl,
1-5) Description: Pollen grains large, isopolar, circular to subcircular in polar view, oblate, angulaperturate, 55 70 lam in equatorial diameter, tricolporate. Colpi about 16 ~tm long, 8 10 ~tm wide at
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equator, almost brevicolpate; margin smooth, straight, thin, bordered by randomly oriented collumellae, ends acute; ora generally circular, 10-13 lam in diameter, costate and lalongate. Nexine ca.2.5 pm thick, almost double the thickness of the sexine; sexine 1 1.5 lam thick, slightly thicker along the equatorial area of aperture, clearly rugulate-reticulate. Specimens observed: 47 Comments: Rugulo-reticulate ornamentation is a diagnostic feature of this morphotype (Table II). Except for slight differences in size and shape, no variation is apparent in observed specimens. In features such as costate ora and thicker nexine than sexine, this morphotype also shows a close similarity to pollen of the extant A. ebenaceum type of the section Conostigma. Holotype: Plate III, 1 3, Slide No. Lig.-9/2 (S) LocaliO' and age: Rajpardi lignite, Lower-Middle Eocene.
Lanagiopollis reitsmae sp. nov. (Plate III, 6 8) Description: Pollen large, sub-triangular in polar view, oblate, isopolar, angulaperturate, 50 68 pm in equatorial diameter; apertures slightly asymmetric in distribution, tricolporate, minutely fossaperturate. Colpi about 12pm long, brevicolpate, generally closed, crassimarginate, bordered by closely spaced, thick and small rugulae; ora comparatively small, 5-8 pm in diameter, lalongate, heavily costate. Nexine distinctly thicker than sexine, almost uniformly thick in mesocolpia and slightly thicker around endoaperture. Mesocolpial sexine _+ uniformly thick while around the endoaperture it is slightly thickened, verrucate along mesocolpia, otherwise clearly rugulate, dupli-to pluribaculate. Specimens observed: 14 Comments: The heavy rugulate verrucate ornamentation and unequal distribution of apertures
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readily differentiate this palynomorph from other described species of Lanagiopollis. It shows some resemblance to L. ruguloverrucatus Morley described from Middle to Late Eocene deposits of Central Java (Morley, 1982). However, the distribution pattern of apertures, the nature of colpi as well as the ornamentation pattern are quite different. In having a characteristic thicker nexine and overall peculiarity of sculpturing, this morphotype somewhat resembles the pollen of extant Alangium ebenaceum (Reitsma, 1970). This species has been named after Dr. T. Reitsma in recognition of his monographic contribution to the palynology of the Alangiaceae. Holotype: Plate III, 7,8, Slide No. Lig.-9/12 (S) Locality and age: Rajpardi lignite, Gujarat, India, Lower-Middle Eocene.
Lanagiopollis rugulatus sp. nov. (Plate IV, 1-5) Description: Pollen grains large, isopolar, triangular in polar view, oblate, angulaperturate, 62-70 pm in equatorial diameter, apertures slightly asymmetric in distribution, tricolporate. Colpi distinct, ca. 13 pm long, 8 10 pm wide at equator, almost brevicolpate; margin smooth, straight, thick, thicker around endoaperture, bordered by thick brochi, ends acute; ora distinct, circular to slightly elliptic, 10 12 pm in diameter, lalongate, heavily costate, margin incurved. Nexine is slightly thicker than sexine, gradually thinning towards aperture, but thickening again around the endoaperture, forming conspicuousely thick costa; sexine also is thicker in mesocolpia, gradually decreasing in thickness towards aperture and again increasing at the equatorial margin of colpi; apocolpial and mesocolpial sexine is prominently rugulate while around both sides of equatorial colpal margins it has a minute areolate appearance. Specimens observed: More than 50. Comments: The triangular shape, slight unequal
P L A T E I11 1 3. 4,5. 6. 7,8.
Lanagiopollis ruguloreticulatus sp. nov., holotype. Slide No. Lig.-9/2 (S). SEM photograph of the similar pollen. SEM photograph of L. reitsmae sp. nov. Lanagiopollis reitsmae sp. nov., holotype. Slide No. Lig.-9/12 (S).
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N.R. P H A D T A R E A N D B T H A K U R
TABLE II Comparative morphology of various species of Lanagiopollis Morley
Taxa
Size in polar view (t-tm)
Ectoaperture Distribution
Length
Ornamentation
Reference
Equatorial width (/am)
( 1) Lanagiopollis regularix Morley (2) L. microrugulatus Morley (3) L. ruguloverrucalus Morley (4) L. nanggulanensis Morley (5) L. emarginatus Morley (6) L. ruguloreticulutus sp. nov. (7) L. reitsma sp. nov. (8) L. ruRulalus sp. nov.
67-78
Radially symmetric 1/2 the radius
Ca 5/am
Finely reticulate
Morley. 1982
68 73
Radially symmetNc 1/3 the radius
7 /am
Micro-eurugulate
Morley, 1982
ca.70
Radially symmemc 1/3 the radius
8 ~m
Rugulo-verrucate
Morley, 1982
75 105
Radially symmetmc 1/2 the radius
6 8 ~tm
Morley, 1982
60 85
Radially symmetric variable
10 p.m
55-70
Radially symmetric 16/am
8 10 gm
Coarsely rugulate to reticulate Eureticulate to eurugulate Rugulo-reticulate
50 68 62 70
Asymmetric Asymmetric
closed
Verrucato-rugulate
8-10/am
Coarsely rugulate
distribution of apertures and distinct coarsely rugulate ornamentation are the diagnostic features of this morphotype by which it can easily be distinguished from other species of Lanagiopollis. In gross morphology it resembles pollen of the section Conostigma. Holotype: Plate IV, 1-3; Slide No. Lig.-9/2 (S) Locality and age: Rajpardi lignite, Lower Middle Eocene.
Age of the Rajpardi lignite In dealing with the detailed stratigraphy of the Cambay Basin and a spatial comparison with that of the Jhagadia-Tarkeswar area in the east, Chandra and Chowdhary (1969) stated that the Tarkeswar Formation was unfossiliferous. Very recently however, a good fossil pollen population has been recovered from the lignite of the Tarkeswar Formation (Thakur and Phadtare, 1989). In the Jhagadia area, the "Nummulitic" fauna
12 gm 13 /am
Morley, 1982 Present work Present work Present work
(without the names of taxa being cited) of the underlying limestone was dated as Middle to Late Eocene (Chandra and Chowdhary, 1969, p.40). As it unconformably overlies the "Nummulitics", the Tarkeswar Formation was considered to be of Early Miocene age, possibly based on its spatial lithostratigraphic correlation with the Kathana Formation of the Cambay Basin. In the Rajpardi area, as the Nummulitic Formation is missing (Kathiara, 1968, p.2), the lignite of the Tarkeswar Formation unconformably overlies the Lower Eocene Vagadkhol Formation. Kathiara (1968) suggests that the Tarkeswar Formation is of Late Eocene to Oligocene age. The pollen/spore spectrum recovered from the Rajpardi lignite (Thakur and Phadtare, 1989 and the present study), in comparison with the palynostratigraphy of various other Tertiary deposits of India (Sah and Mehrotra, 1988), hint at a still older age of Early to Middle Eocene. Other faunal as well as stratigraphic evidence is essential to verify the age of the Rajpardi lignite.
PLATE IV I 3. Lanagiopollis rugulatus sp. nov., holotype. Slide No. Lig.-9/2 (S). 4,5. SEM photograph of the similar grain.
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Indian record of the fossil
N.R. P H A D r A R E A N D B. T H A K U R
Alangium
An examination of the palaeofloristic literature on the different Tertiary deposits of India reveals that amongst fossil angiosperm taxa so far reported, Alangium is perhaps the only genus convincingly documented by its almost all parts, viz., wood, leaves, pollen and possibly even fruits. The acceptable existing Indian record of fossil remains attributable to Alangium is abstracted in Table III.
Wood: The fossil wood of Alangium (Alangioxylon sclariformae Awasthi) is so far known from a single report from the Cuddalore Sandstone of South India (Awasthi, 1968). Having characteristic xylotomical features such as small- to medium-sized vessels with scalariform plates, 1 3 seriate long and heterogenous rays and the nonseptate fibres, it closely resembles the wood of extant Alangium javanicum (Awasthi, 1974) of the section Cono-
stigma. Leaves: The first Indian record of fossil leaf
TABLE Ill Fossil remains of Alangium from Indian Tertiaries Taxa Wood (1) Alangioxylon sclar(formae Leaf (2) Alangium salvi(folium Pollen (3) Tricolporopilites sp.* (4) Favitricolporites grandis
Affinity
Age
Area
Remarks
Section Conostigma
Eocene ?
Cuddalore sst.
Awasthi (1968)
Section Alangium
Miocene
Ratnagiri lignite
Dalvi and Kulkarni (1982)
Section Marlea ? Section Marlea
Assam Cauvery Basin Kachchh
Biswas (1962) Venkatachala and Rawat (1972) Kar (1985)
Kachchh Kerala
Kar (1985) Raha et al. (1986)
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Neyveli lignite Neyveli lignite Assam
Ramanujam (1966) Ramanujam (1966) Sah and Dutta (1968) Phadtare and Kulkarni (1983) Nandi ( 1981 ) Nandi (1981) Thanikaimoni et al. (1984)
(10) L. emarginatus
Section Conostigma
( 11) L. ruguloreticulatus
Section Conostigma
(I 2) L. rugulatus
Section Conostigma
(13) L. reitsmae
Section Conost~gma
(14) Margocolporites dubius (15) M. complexum (I 6) Favitricolporites complex
Section Marlea Section Marlea Section Marlea
Late Paleocene Early Eocene Early Miocene Early-Middle Eocene Early Eocene Early Middle Eocene Early-Middle Eocene Early-Middle Eocene Early-Middle Eocene Early-Middle Eocene Early-Middle Eocene Early Middle Eocene Eocene Eocene Oligocene
(17) Palaeoalangiumpollis zoniporatus
Section Alangium
Miocene
Ratnagiri lignite
(18) Ghoshiadites reticulatus (19) Foveotricolporites foveolatus (20) Ahmgium havilandii
Section Conostigma Section Marlea Section Conostigma
Miocene Miocene MiocenePliocene
Assam Assam Assam
(5) Tricolporopilites robustus*
Section Conostigma
(6) Pillicieroipollis langenheimii (7) Pillicieroipollis langenheimii
Section Conostigma Section Conostigma
(8) Pillicieroipollis langenheimii
Section Conostigma
(9) Lanagiopollis microrugulatus
Section Conostigma
*Awaiting confirmation.
FOSSIL POLLEN OF AL.4NGI(M
impressions attributed to extant Alangium (Marlea) was from the Pleistocene deposits of the Karewa Basin (Puri, 1953). Subsequently, VishnuMittre (1964) considered it as an ecologic misfit in a temperate flora. The distinctly dentate margin of these leaves (Puri, 1953, fig.6) certainly indicates that they do not belong to Alangium (Eyde et al., 1969). Well-preserved leaf compressions resembling extant Alangium have been reported from the Miocene lignite of Ratnagiri. Some of the leaves, in their epidermal characters such as paracytic stomata, unicellular and finger-shaped hairs confined exclusively to abaxial surfaces, etc., closely resemble Alangium salviffolium (L.) Wangerin, at present found in drier parts of plains and hilly tracts throughout India. Detailed comparative studies of the fossil cuticles and those of A. salviifolium (Dalvi and Kulkarni, 1982) confrm that during the Miocene, A. salviifolium was one of the common elements of the Western Ghat Flora. Fruits: The first collection of fossil fruits from lignite outcrops of the Ratnagiri area was made by Wilkinson (1871). Some of the fruits from his collection were provisionally identified by him as Terminalia. However, an extensive carpologic collection from different lignitic exposures of this area, indicates that a good number of fossil fruits closely resemble the extant Alangium in their morphology and anatomy (Kulkarni and Phadtare, unpublished work). Morphological features, such as 6 8 longitudinal ridges, size, shape and anatomical characters, viz., bilocular ovary, unequal carpel size, smaller carpel abortive and nature of stone cells, etc., exhibited by the fossil fruits are reasonably well comparable with A. platonifolium (Eyde et al., 1969). Since the fruits of different species of Alangium show a considerable overlap in their gross morphology and anatomy, a systematic study of the carpology of the family Alangiaceae will be the only way to confirm this affinity. Pollen: In comparison with megafossil remains, a very good pollen record of fossil Alangium is available from different Tertiary deposits of India. The first Indian report of fossil pollen directly comparable with extant Alangium is that of Palaeoalangiumpollis zoniporatus Phadtare and Kulkarni, (1983) recovered from the Ratnagiri
293
(Miocene) lignite of Maharashtra (Phadtare, 1982: Phadtare and Kulkarni, 1983). In its characteristic features such as its 4-6 zoniporate nature and very distinctly heterogemmate ornamentation, it closely resembles the pollen of Alangium salvfi['olium. Palynofloristic studies on the Tertiary (Matanomadh, Naredi and Harudi Formations) exposures of Kachchh (formerly spelled at Kutch) by Sah and Kar (1969) and Kar (1985) have documented plentiful pollen closely resembling those of the section Conostigma. Initially, it was reported from the Lower-Eocene Naredi Formation as Pellicieroipollis langenheimii Sah and Kar (1969). Subsequently, similar palynomorphs have also been recovered from near Lakhpat and Rataria (Kar, 1985). The natural affinity of this palynomorph was earlier suspected by Muller (1981), who stated that it could be comparable to Alangium pollen rather than that of Pelliciera. Muller's view was supported by Morley (1982) and further strengthened by Thanikaimoni et al., (1984). On reexamination of holotype preparations, it was observed that none of the pollen spedimens assigned to Pellicieroipollis show the generic character "negative reticulum" (= S-LO pattern). The close similarity between these fossil pollen grains and those of the section Conostigma (Morley, 1982) strongly indicate that during the Early Eocene the genus Alangium was well established in the Kachchh area. This is further supported by the report of P. langenheimii and different species of Lanagiopollis from the Rajpardi lignite deposit situated towards the southeastern side of Kachchh (Thakur and Phadtare, 1989). The presence of similar Alangium pollen in the EarlyEocene Naredi Formation and Rajpardi lignite of the Tarkeswar Formation, strongly indicates that both formations were deposited during the same geologic epoch. Along with Pellicieroipollis langenheimii and species of Lanagiopollis, other palynomorphs such as Proxapertites operculatus Van der Hammen, Lakiapollis ovatus Venkatachala and Kar, Dandotiaspora dilata (Mathur) Sah, Kar and Singh, Arengapollenites echinatus Kar, etc., have also been recovered from this lignite and this further supports the possibility that this lignite is of Early- to Middle-Eocene age. Another form-genus Tricolporopilites Kar with
296
closely comparable to those of the extant genus Alangium. These pollen grains have been systematically described under appropriate species of Pellicieroipollis and Lanagiopollis. The fossil records of Alangium suggest that the family Alangiaceae can reasonably be traced back to the Late Paleocene. The present data and a critical review of existing Indian literature on fossil Alangium lead to the following further inferences. (1) The section Marlea of the genus Alangium first appears in the Upper Paleocene of Assam. (2) Probably during the Early Eocene, members of the section Marlea become more widely distributed and extended into South India. In Assam, Marlea continued to thrive until the Miocene and during this epoch probably more than one member of the section Conostigma apeared. (3) The earliest appearance of the section Conostigma is evidenced by the various Eocene reports from South India. During the same period, it also spread over the Gujarat and Kachchh areas of Western India. (4) Alangium salviifolium, a member of the section Alangium, appears to have been introduced into the Indian subcontinent during the Middle Miocene.
Acknowledgements Authors are grateful to the Director, Wadia Institute of Himalayan Geology for his kind permission to carry out this research work. Financial assistance from D.S.T., the Government of India (Bengal Fan Project) is thankfully acknowledged. The informal co-operation, assistance and help extended by the Manager, Jhagadia Lignite Corporation (G.M.D.C. Gujarat State Government), Mr. R.D. Desai, Sr. Geologist and other official personnel during the field work is greatly appreciated.
References Awasthi, N., 1968. A new fossil wood belonging to the family Alangiaceae from the Tertiary of South India. Palaeobotanist, 17: 322-325. Awasthi, N., 1974. Neogene Angiospermous woods. In: Surange et ah (Editors) Aspects and Appraisal of Indian Palaeobotany. B.S.I.P. Lucknow, pp.341-358.
N.R. P H A D T A R E A N D B. T H A K U R
Banerjee, D., 1964. A note on the microflora from Surma (Miocene) of Garo Hills, Assam. Bull. Geol. Min. Metall. Soc. India, 25: 1-8. Biswas, B., 1962. Stratigraphy of the Mahadev, Langpar, Cherra and Tura Formation. Assam, India. Bull. Geol. Min. Metall. Soc. India, 25: 1-48. Bose, R.H., 1908. Note on the geology and mineral resources of Rajpipla state. Rec. Geol. Surv. India, 32:167 180. Chandler, M.E.J., 1964. The Lower Tertiary Floras of Southern England, 4. A summary and survey of findings in the light of recent observations. Br. Mus. (Nat. Hist), London, 151 p. Chandra, P.K. and Chowdhary, L.R., 1969. Stratigraphy of the Cambay Basin. Bull. Oil Nat. Gas Comm., 6(2): 34-50. Cookson, I.C., 1957. On some Australian Tertiary spores and pollen grains that extend the geological and geographical distribution of living genera. Proc. R. Soc. Victoria, 69: 41-54. Dalvi, N.S. and Kulkarni, A.R., 1982. Leaf cuticles from Lignitic beds of Ratnagiri Dist., Maharashtra. Geophytology, 12(2):223 232. Deb, U., Baksi, S.K. and Ghosh, A.K., 1973. On the age of Neyveli lignite - - a palynological approach. Quat. J. Geol. Min. Metall. Soc. India, 45(1): 23-38. Desikachar, S.V., 1984. Oil gas deposits in the delta sequence of sediments in Cambay basin and Upper Assam in India. J.Geoh Soc. India, 25(4): 199-219. Erdtman, G., 1952. Pollen morphology and plant taxonomy. I Angiosperms. Almqvist Wiksell, Stockholm. 539 pp. Eyde, R.H., Bartlett, A. and Barghoorn, E S., 1969. Fossil record of Alangium. Bull. Torrey Bot. Club, 96:288 314. Fairchild, W.F. and Elsik, W.C., 1969. Characteristic palynomorphs of the Lower Tertiary in the Gulf Coast. Palaeontographica B, 128: 81-89. Gadekar, D.R., 1975. Geology of Tertiary rocks of south Gujarat with special reference to their stratigraphy and sedimentation. Univ. Baroda, (unpublished Thesis). Gadekar, D.R., 1977. Sedimentary structures in the Tertiary rocks of South Gujarat and their environmental significance. J. Geol. Soc. India, 18:549 557. Kathiara, R.S., 1968. Lignite deposits in Bhuri area, Broach Dish. Gujarat. Mineral Wealth, 4(4): 12 16. Kar, R.K., 1979. Palynological fossils from the Oligocene sediments and their biostratigraphy in the distr, of Kutch, Western India. Palaeobotanist, 26(1): 16 45. Kar, R.K., 1985. Fossil flora of Kuchchh. Palaeobotanist, 34: ! -280. Kar, R.K. and Saxena, R.K., 1981. Palynological investigation of a bore core near Rataria, Southern Kutch, Gujarat. Geophytology, 11(2): 103-124. Krutzsch, W.. 1962. Stratigraphisch bzw, botanisch wichtige neue sporen-und pollen formen aus dem deutschen Tertiar. Geologie (Berlin), 11:265 307. Krutzsch, W., 1969. Uber einige stratigraphisch wichtige neue longaxoner pollen aus dem mitteleuropaischen Alttertiar. Geologie (Berlin), 18(4): 472-487. Moore, P.D. and Webb, J.A., 1978. An lllustrated Guide to Pollen Analysis. Hodder Stoughton, London. 133 pp. Morley, R.J., 1982. Fossil pollen attributable to Alangium Lamarck (Alangiaceae) from the Tertiary of Malesia. Rev. Palaeobot. Palynol., 36: 65-94.
295
FOSSIL POLLEN OF ALANGIUM
tricolporites foveolatus Nandi (Nandi, 1981, pl.2, figs.45,47; Thanikaimoni et al., 1984, figs.638-646) from the Late Miocene of Upper Assam are certainly pollen of Alangium. Fossil pollen grains closely comparable to those of Alangium havilandii Bloembergen are also present at the same locality (Thanikaimoni et al., 1984, figs.653-661). Stratigraphic antiquity The stratigraphic palaeogeography of Alangium in global perspective (Eyde et al., 1969; Reitsma, 1970; Muller, 1981 and Morley, 1982), is fairly clear due to the numerous fossil reports thereof from various countries, such as North America (Traverse, 1955), Europe (Krutzsch, 1962, 1969; Chandler, 1964; Pacltova, 1966; Fairchild and Elsik, 1969: Nagy, 1973), Africa (Puri, 1964), tropical islands of the Indian and Pacific Oceans (Cookson, 1957; Muller, 1964; Morley, 1982) and Japan (Sato, 1963). Its Indian stratigraphic history however, is much more dubious. The foregoing appraisal of the Indian records of fossil Alangium indicates that the monogeneric family Alangiaceae had a wide (Paleocene to Late Miocene) temporal geologic distribution. Amongst the Indian reports of fossil Alangium known and available in the literature, only those which are confirmed, accepted or reasonably acceptable have been considered. Upper Paleocene: The earliest appearance of fossil Alangium in the Indian sub-continent is from Assam. Tricolporipites sp. reported from the Cherra Formation (Biswas, 1962; p.37, pl.5, fig.3), being a synonym of the Favitricolporites complex Sah and Dutta (1968, p. 190), compares reasonably well with pollen of the section Merlea. If its alangiaceous affinity is confirmed, the earliest appearance of Alangium can be extended down to the Late Paleocene. Eocene: Following its first appearance in the Late Paleocene, the presence of Alangium in the Early Eocene of Assam is marked by the report of Favitricolporites complex Sah and Dutta (1968) from the Tura Formation. Favitricolporites grandis (Venkatachala and Rawat, 1972) representing the section Marlea, occurs in Lower-Middle Eocene sediments of the Cauvery Basin. Similarly, Margo-
colporites dubius and M. complexum from the Neyveli lignite (Ramanujam, 1966) have an alangiaceous affinity (Reitsma, 1970) and indicate the existence of a member of the section Marlea. Considering the Cuddalore Sandstone and associated lignite to be of Eocene age (Deb et a1.1973; Muller, 1981), the fossil wood resembling A.javanicum (Awasthi, 1974) marks the presence of a conostigmoid member. Different species of Lanagiopollis and P. langenheimii recovered from the Tarkeswar Formation of Gujarat and described in this communication, indicate a close affinity with pollen of the section Conostigma. Species of Pellicieroipollis (Sah and Kar, 1969; Kar, 1985) known from the Early to Middle Eocene of Kachchh confirm that members of the section Conostigma were growing profusely in the Gujarat and Kachchh areas. Oligocene: The fossil pollen described as Favitricolporites complex, Tetracolporites paucus and T. onagraceoides (Sah and Dutta, 1968) have many features in common with eureticulate forms of the section Marlea. This represents an acceptable Oligocene record of fossil Alangium from the Baragolai Formation in Assam. Miocene: The continuing presence of'Alangium in the Miocene sediments of Assam is evidenced by Favitricolporites foveolatus, representing the section Marlea [=A. griffithii (Clarke) Harms] and Ghoshiadites reticulatus resembling the pollen of A. nobile (Clarke) Harms from the section Conostigma (Thanikaimoni et al., 1984). Pollen very similar to that of A. havilandii is known from the Late Miocene to Pliocene of Assam and further indicates that, in addition to Marlea, possibly more than one member of Conostigma was thriving in Assam. In Western India, the report of Palaeoalangiumpollis zoniporatus (Phadtare and Kulkarni, 1983) and leaf cuticles (Dalvi and Kulkarni,1982) from the Middle-Miocene lignite of Ratnagiri confirm the presence of the section Alangium (= A. salviifolium) in Tertiary sediments of India.
Summary and conclusions Detailed palynological studies on the Eocene lignite of Gujarat reveal an abundance of pollen
FOSSIL POLLEN OF ALANGIUM
Muller, J., 1964. Palynological contribution ot the history of Tertiary vegetation in N.W. Borneo. 10th Int. Bot. Congr., Edinburgh, Abstr., p.271. Muller, J., 1981. Fossil pollen records of extant Angiosperms. Bot. Rev., 47: 1-142. Nagy, E., 1962. New pollen species from the Lower Miocene of the Bakony mountain. Acta Bot. Acad. Sci. Hung., 8: 153 163. Nandi, B., 1981. Microfloral investigation on the Neogene formations of Moran and Mahorkatiya wells. Upper Assam, India. Geophytology, 11: 27-40. Navale, G.K.B. and Misra, B.K., 1979. Some new pollen grains from Neyveli lignite Tamil Nadu, India. Geophytology, 8, 226-239. Pacltova, B., 1966. The results of micropalaeobotanical studies of the Chattian-Aquitanian complex in Slovakia, Rozpravy Cesk. Akad. Ved Rada Mat, Prirod. Ved., 76(13): 1-68. Phadtare, N.R., 1982. Floristic studies on the lignitic beds of Ratnagiri Distt. Thesis, University Bombay, 275 pp. (Unpublished). Phadtare, N.R. and Kulkarni, A.R., 1983. Palynological assemblage of lignitic exposure of Ratnagiri Distt. Proc. Xth Ind. Coll. Micropaleontol Stratigr., pp.515-532. Puri, G.S., 1953. Some plant remains of the cornaceae from the Karewa deposits of the Kashmir Valley, India, Palaeobotanist, 2: 107-110. Puri, G.S., 1964. Some palynological studies on the past vegetation of Nigeria. 10th Int. Bot. Congr., Edinburgh, Abstr., p.451. Raha, P.K., Rajendran, C.P. and Kar, R.K., 1986. Eocene palynofossils from the subcrop of Kerala. Bull. Geol. Min. Metall. Soc. India, 54: 227-232. Ramanujam, C.G.K., 1966. Palynology of the Miocene lignite from South Arcot Distt. Madras, India. Pollen Spores, 8(1): 149-203. Ramanujam, C.G.K., 1968. Some observations on the flora of the Cuddalore Sandstone Series. In: Cretaceous-Tertiary Formations of South India. Geol. Soc. Ind. Mem., 2: 271-286. Reitsma, T., 1970. Pollen morphology of the Alangiaceae. Rev. Palaeobot. Palynol., 10: 249-332. Sah, S.C.D. and Dutta, S.K., 1968. Palynostratigraphy of the Tertiary Sedimentary Formations of Assam: 2. Stratigraphic significance of spores and pollen in the Tertiary Succession of Assam. Palaeobotanist, 16(2): 177-195. Sah, S.C.D. and Kar, R.K., 1969. Palynology of Laki sediments in Kutch - - 3. Pollen from the bore holes around Jhulradi, Baranda and Panandhro. Palaeobotanist, 18(2): 127-142.
297 Sah, S.C.D. and Mehrotra, N.C., 1988. Palynostratigraphy of the Tertiary sediments of India. Geol. Surv. Ind. Spec. Publ., 1 l(II): 17-34. Sato, W., 1963. Palynological study on Miocene sediments of Hokkaido, Japan. J. Fac. Sci. Hokkaido Univ., Ser.4, 12: 1 93. Saxena, R.K., 1979. Reworked Cretaceous spores and pollen grains from the Matanomodh Formation (Paleocene). Kutch, India. Palaeobotanist, 26(2): 167-174 Sudhakar, R. and Roy, T.K., 1959. Progress report on the Geology of Tertiary Formations of Borach and Surat districts, Bombay state; season 1958-1959; (Unpubl. Rep. O.N.G.C.). Thakur, B. and Phadtare, N.R., 1989. Fossil pollen of Alangium from the Jhagadia lignite (Gujarat) and its stratigraphic significance. XIII Indian Coll. Micropaleontol. Stratigr., pp.64. (Abstr.). Thanikaimoni, G., Caratini, C., Venkatachala, B.S. and others, 1984. Selected Tertiary angiosperm pollen from India and their relationship with African Tertiary Pollen. Institute Fran~ais De Pondichery. Trav. Sect. Sci Tech., XIX, 1 - 9 2 pp. Traverse, A., 1955. Pollen analysis of the Brandon lignite of Vermont. U.S. Bur. Mines Rep. Invest., 5151: 1-107. Venkatachala, B.S., 1973. Palynological evidence on the age of Cuddalore Sandstone. Geophytology, 3:145 149. Venkatachala, B.S., Caratini, C. and others, 1988. PalaeoceneEocene marker pollen from India and tropical Africa. Palaeobotanist, 37(1): 1-25. Venkatachala, B.S. and Kar, R.K., 1969. Palynology of the Tertiary Sediments of Kutch-l. Spores and pollen from bore hole no.14. Palaeobotanist, 17(2): 157 178. Venkatachala, B.S. and Rawat, M.S., 1972. Palynology of the Tertiary Sediments in the Cauvery Basin-l. PalaeoceneEocene palynoflora from the subsurface. Proc. Semin. Palaeo-Palynol. Indian Stratigr., 1971, Calcutta, pp.292-335. Vishnu-Mittre, 1964. Floristic and ecological reconsiderations of the Pleistocene plant impressions from Kashmir. Palaeobotanist, 13: 308-327. Wilkinson, 1871. Sketch of geological structure of the Southern Konkan. Rec. Geol. Surv. India, 4: 44-47. Wolfe, A. and Tanai, T., 1980. The Miocene Seldovia Point Flora for the Kenai Group Alaska. U.S. Geol. Surv. Prof. Pap., 1105:52 pp. Yeramyan, E.N., 1967. The types of sporoderm of microspores in the representatives of the order Cornales and their genetic affinities. Bot. Zn., 52(9): 1287-1294 (in Russian).
28 l
Printed in The Netherlands
Fossil pollen of Alangium from the Eocene lignite of Gujarat, India, with comments on its stratigraphic antiquity N.R. Phadtare and B a n d a n a T h a k u r Palynology Laboratory, Wadia Institute o[ Himalayan Geology, Dehradun 248001 (India)
(Received May 17, 1989; revised and accepted March 7, 1990)
ABSTRACT Phadtare, N.R. and Thakur, B., 1990. Fossil pollen of Alangium from the Eocene lignite of Gujarat, India, with comments on its stratigraphic antiquity. Rev. Palaeobot. Palynol., 63: 281--297. Palynological studies on the Rajpardi lignite of Gujarat have yielded plentiful pollen grains closely comparable to those of extant Alangium Lamarck. These palynomorphs have been described under five different species of Lanagiopollis Morley (L. microrugulatus Morley, L. emarginatus Morley, L. ruguloreticulatus sp. nov., L. reitsmae sp. nov. and L. rugulatus sp. nov.) and Pellicieroipollis langenheimii Sah and Kar. The characteristic palynoflora of the Rajpardi lignite, as compared with those from other Tertiary deposits of India, indicates that this deposit of the Tarkeswar Formation is most probably of Early to Middle Eocene age. Detailed appraisal of the available Indian literature on fossil Alangium indicates that the section Marlea possibly existed in India during the Late Paleocene. Subsequently, during the Eocene it was accompanied by members of the section Conostigma. The section Alangium, however, appeared later, sometime during the Miocene.
Introduction
Existing and available records of fossil plant remains convincingly resembling modern Alangium are represented by wood (Awasthi, 1968), leaves (Wolfe and Tanai, 1980; Dalvi and Kulkarni, 1982), fruits (Eyde et al., 1969 and references therein) and a number of pollen grains (Muller, 1981; Morley, 1982; Phadtare and Kulkarni, 1983 and Thakur and Phadtare, 1989). The intercontinental as well as long-ranging temporal distribution of this fossil record clearly indicates that, although at present Alangium is confined to Africa and S.E. Asia, during the Mid-Tertiary period it had a pantropical distribution. In spite of the peculiar pollen morphological features (Reitsma, 1970; Morley, 1982) of this monogeneric family, that are well reflected also in the fossil record, its stratigraphic significance is still a matter for discussion. Remains of Alangium are well documented in 0034-6667/90/$03.50
c,~~) 1990 Elsevier Science Publishers B.V.
different Tertiary exposures in India. In this communication an attempt is made to describe some additional palynomorphs resembling those of extant Alangium. They have been recovered from a new Tertiary exposure of the Rajpardi lignite (Tarkeswar Formation, Table I) in southcentral Gujarat (Fig. 1). A critical review of existing literature on fossil remains of Alangium from different Tertiary exposures in India and a discussion of its stratigraphic antiquity are also presented. The Rajpardi lignite mine is a few kilometers away from Ankleswar and very close to the eastern margin of the South Cambay Basin. The detailed geology of the Jhagadia Tarkeswar area has been discussed by many workers (Bose, 1908; Sudhakar and Roy, 1959; Kathiara, 1968; Gadekar, 1975, 1977 and many unpublished reports of the ONGC (Oil and Natural Gas Commission). A more than 2000 m thick sequence of Tertiary sediments exposed for a small stretch around the
282
N.R. PHADTAREAND B. THAKUR
TABLE I Stratigraphy of the area (After G.M.D.C., 1983 and Kathiara, 1968) Age Quartenary
Recent Pleistocene
Tertiary
Pliocene Miocene
Formation
Lithology
Alluvium
Varied coloured sand, soil and Kankars
Jhagadia Formation
Light-coloured sandstone marls, limestone and conglomerate
Kand Formation
Limestone marls and clay with sandstone, sand and agate-bearing conglomorate
Babaguru Formation
Ferruginous sandstone, agate-bearing conglomorate and varied clay, gray sandstone and white sand
U M
Oligocene
Eocene
Gray, yellow, brown friable sandston with clay lenses. I
Tarkeshwar Formation
Bentonitic clays with lignite bed and lenses of I carbonaceous clay, sandstone and lignite II
U M
Nummulitic Formation
Nummulitic limestone, clay with sandstone lenses
L
Vagadkhol Formation
Bentonitic clays, friable sandstone and conglomerate
U L
D. Traps
Basalts with basic intrusions
Paleocene Cretaceous
Dashed block marks the sampling strata.
Jhagadia-Tarkeswar area unconformably overlies the Deccan Traps. The lowermost post-trappean sediments, equivalent to the Olpad Formation (Paleocene) of the Cambay Basin, are of the Vagadkhol Formation. In the Jhagadia area, the latter formation is unconformably overlain by the Nummulitic limestone of the Late Eocene (Chandra and Chowdhary, 1969). On the eastern side of Jhagadia, around Bhuri village where the lignite is being mined, the "Nummulitics" are, however, absent (Kathiara, 1968; Gadekar, 1977). Therefore, in the mining area the Vagadkhol Formation is unconformably overlain by the clay and lignite of the Tarkeswar Formation (Table I). The younger stratigraphic sequence above the Tarkeswar Formation (i.e., the Baba Guru Formation--*Kand Formation--*Jhagadia Formation, etc.) is similar to that of the Cambay Basin (Chandra and Chowdhary, 1969; Desikachar, 1984). The lignite samples processed for this study come from the lower part of the Tarkeswar Formation.
Material and methods
During two field visits to this mine, lignite samples were collected from measured vertical profiles (Fig. 1). The slandard conventional laboratory techniques (concentrated HNO 3 and 10% KOH treatments) were followed for recovery of microfossils from systematically cataloged and airdried samples. After chemical treatments, the recovered organic residue was subjected to ultrasonic sieving (100 jam and 10 jam sieves) to remove undesired particles and to increase microfossil concentration. Afater preparing 20 slides for optical microscopy, the remaining residue of each processed sample was treated with water: alcohol and alcohol: acetone grades, mounted on stubs, oven dried (60°C), coated with gold palladium (100A 125A) and scanned under a Philips 515 SEM microscope. Each recovered palynomorph resembling the extant Alangium has been described systematically,
283
FOSSIL POLLEN OF 4LANGIUM
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following the terminologies of Erdtman (1952) and Moore and Webb (1978). The description of each morphotype is based mainly on the optical illustrations. Nomenclaturai considerations
The fossil pollen grains resembling those found in extant Alangium Lamarck are classified under different form-genera. This nomenclatural ambiguity has already been discussed in detail by Morley (1982) and Kar (1985). Knowing the morphologic variability exhibited by extant Alangium pollen (Yeramyan, 1967; Eyde et al., 1969; Reitsma, 1970), a minimum of four form-genera is required
to adequately encompass the range of diversit' observed in fossil Alangium pollen. The generic diagnosis of Alangiopollis Krutzscl (1962) as emended by Morley (1982), accomodate the alangiaceous fossil palynomorphs having th striato-reticulate type of ornamentation. Similarl) another form-genus, Lanagiopollis Morley (1982 incorporates only eureticulate to eurugulate polle specimens. Pollen grains resembling those c modern Alangium are also found in species c several other morphographic genera such as Pell cieroipollis langenheimii Sah and Kar (1969 Margocolporites dubius Ramanujam and M. con plexum Ramanujam (1966), Ghoshiadites reticuh tus Nandi (1981), Foveotricolporites foveolan
284
Nandi (1981), Tricolporipilites robustus (Kar and Saxena) Kar (1985) and Palaeoalangiumpollis zoniporatus Phadtare and Kulkarni (1983), etc. To avoid nomenclatural confusion, the palynomorphs here illustrated are described under existing appropriate form-genera. The nomenclatural revision of all the known fossil palynomorphs comparable to modern Alangium pollen is a taxonomic aspect and will be dealt with separately.
Pollen description Form-genus: Pellicieroipoilis Sah and Kar 1969 Pellicieroipollis Sah and Kar, p.133, plate 2, fig.58, Slide No. BSIP-3377. Emended diagnosis: Pollen grains large, oblate, triangular to sub-triangular in polar view, tricolporate, rarely di- or tetracolporate, generally brevicolpate; ora costate, distinctly lalongate; exine thick, mesocolpial nexine slightly thicker than sexine; ornamentation reticulate, generally homobrochate, often heterobrochate, muri simple- to duplibaculate.
Type species: Pellicieroipollis langenheimii Sah and Kar.
Holotype: Sah and Kar, 1969; pl.2, fig.58 Slide No. BSIP-3377.
Revised description: Pollen grain large (59 lain in equatorial diameter), oblate, isopolar, rounded triangular in polar view, tricolporate, brevicolpate; colpi tenuimarginate, margin straight, bordered with _+ elongated and slightly radiating brochi, ends acute; ora clearly costate, about 10 p.m wide, lalongate; mesocolpial nexine slightly thicker than sexine, ornamentation clearly reticulate. Remarks: The type material of Pellicieroipollis langenheimii Sah and Kar (1969) deposited in the repository of the Birbal Sahni Institute of Paleobo-
N R . P H A D T A R E A N D B. T H A K U R
tany, Lucknow, India (Slide Nos.3359, 3376 to 3380) was re-examined in view of the doubts raised by Muller (1981) and subsequently supported by Morley (1982), suggesting the possibility of its alangiaceous affinity. The revised morphological observations of the type species of this genus indicate its close resemblance to pollen of extant Alangium, particularly to that of the section Conostigma.
Pellicieroipollis langehheimii Sah and Kar (Plate I, 1-6). Description: Pollen grains large, 50 75jam in equatorial diameter, isopolar, triangular to subtriangular in polar view, angulaperturate, tri(rarely tetra) colporate. Colpi crassimarginate, distinctly brevicolpate, slightly fossaperturate, narrow, 6-10 gm wide along equator, ends acute; margins distinct, straight, bordered with thin to moderately thick margo or in some cases a row of minute brochi. Endoaperture clearly orate, ora circular to transversely elliptic, 8-12 tam in width, lalongate, distinctly costate, margin slightly incurved. Nexine slightly thicker than sexine along the mesocolpial region, whereas along endoapertures it is much thicker (5 tam). Sexine distinctly reticulate, reticulum generally homobrochate, often heterobrochate. When heterobrochate, the smaller, slightly elongated and radiating brochi are present around colpal ends, apocolpial brochi are medium and + sub-angular while those in mesocolpial area are bigger and polygonal. Specimens observed: More than 100. Variability: The examined specimens show marked variation in size ranging from 42 ~tm to 75 lain. To some extent the nature of the margin and width and length of colpi are also variable but within the circumscription of the species diagnosis. Comments: The above illustrated and described pollen is very similar to that of the Alangium ebenaceum Harms type (=A.javanicum (Blume) Wangerin of Reitsma, 1970) of the section Conos-
PLATE I
1 3. PellicieroipollislangenheimiiSah and Kar. 4. Obliqueequatorial viewof the similar pollen showingcircular, lalongate and costate ora. 5,6. SEM photograph of the similar pollen.
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FOSSIL POLLEN OF ALANG1UM
tigma. It is also very closely comparable with the following fossil pollen specimen. 1981 Ghoshiadites reticulatus Nandi in Nandi, 1981, p.33, pl.2, fig.47 1984 Ghoshiadites reticulatus Nandi in Thanikaimoni et al., 1984; pl.46, figs.643 646 1981 Foviotricolporitesfoveolatus Nandi in Nandi, 1981; p.33, pl.2 fig.45. 1984 Foveotricolporites foveolatus Nandi in Thanikaimoni et
287
Comments: In general features, these pollen grains very closely resemble L. microrugulatus described by Moreley (1982) from Late-Eocene deposits of Central Java. A slight variation is, however, observed in the size of rugulae. The holotype is very finely eurugulate whereas the above-described specimen has slightly coarser ornamentation. The morphological features of this pollen suggest its affinity with the A. ebenaceum type of the section Conostigma (Morley, 1982).
al., 1984; pl.46, figs.638-642.
Form-genus: Lanagiopollis Morley Type Species: L. regularis Morley Holotype: Morley, 1982, pl. I, figs.3,4; Slide No. PW 1313-2. Generic diagnosis: Pollen grains large (60-105 lam), oblate, radially symmetrical, tricolporate or (rarely) ? di or tetracolporate, nexine thinner or thicker than sexine, often showing distinct thinning toward apertures; exine regularly or irregularly eureticulate or eurugulate; muri simplibaculate to pluribaculate. Lanagiopollis microrugulatus Morley, 1982 (Plate ll, 1 4) Description: Pollen grains large, oblate, isopolar, tricolporate, rounded triangular, angulaperturate, 55-70 lam in equatorial diameter; colpi tenuimarginate, 12-15 ~tm long, almost brevicolpate, fossaperturate, narrow, 8 10 lam wide at equator, ends acute, margins almost straight, smooth and bordered by radiating rows of rugulae. Endoaperture distinctly orate, ora circular to elliptic, 10-13 ~tm wide, clearly lalongate, costate, margin slightly incurved. Mesocolpial nexine characteristically thicker than sexine and thinning towards aperture, sexine (1.5 lam) thicker in mesocolpia and slightly thinning towards aperture, clearly microrugulate, simplibaculate.
PLATE II I 3. Lanagiopollis microrugulatus Morley. Slide No. Lig.-9/1 (S). 4. SEM photograph of the similar pollen. 5,6. Lanagiopollis emarginatus Morley. Slide No. Lig.-9/8 (S).
Lanagiopollis emarginatus Morley, 1982 (Plate II, 5,6) Description: Pollen grains large, isopolar, oblate, circular in polar view, tricolporate, planaperturate, 45 65 I~m in equatorial diameter: distinctly brevicolpate. Colpi characteristically tenuimarginate, inconspicuous, 7-10 p,m wide at equator, margins smooth, straight, beset with slightly smaller brochi. Endoaperture conspicuous, distinctly orate, ora circular to slightly elliptic, lalongate, about 10 I~m in diameter, costate; costae ca 3 lain thick, slightly incurved. Nexine imperceptibly thicker than sexine, thinning towards aperture; sexine eureticulate, mesocolpial columellae larger than those towards the apertures, almost homobrochate and simplibaculate. Comments: This palynomorph has previously been reported only from the Mio Pliocene of Malesia (Morley 1982). The present record indicates that, at least in the Indian subcontinent, the age of L. emarginatus can certainly be extended back to the Middle Eocene. It closely resembles pollen of A. havilandii Bloembergen (Morley, 1982). Lanagiopollis ruguloreticulatus sp. nov. (Plate IIl,
1-5) Description: Pollen grains large, isopolar, circular to subcircular in polar view, oblate, angulaperturate, 55 70 lam in equatorial diameter, tricolporate. Colpi about 16 ~tm long, 8 10 ~tm wide at
bm~ ~mq
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FOSSIL POLLEN OF ALANGIUM
equator, almost brevicolpate; margin smooth, straight, thin, bordered by randomly oriented collumellae, ends acute; ora generally circular, 10-13 lam in diameter, costate and lalongate. Nexine ca.2.5 pm thick, almost double the thickness of the sexine; sexine 1 1.5 lam thick, slightly thicker along the equatorial area of aperture, clearly rugulate-reticulate. Specimens observed: 47 Comments: Rugulo-reticulate ornamentation is a diagnostic feature of this morphotype (Table II). Except for slight differences in size and shape, no variation is apparent in observed specimens. In features such as costate ora and thicker nexine than sexine, this morphotype also shows a close similarity to pollen of the extant A. ebenaceum type of the section Conostigma. Holotype: Plate III, 1 3, Slide No. Lig.-9/2 (S) LocaliO' and age: Rajpardi lignite, Lower-Middle Eocene.
Lanagiopollis reitsmae sp. nov. (Plate III, 6 8) Description: Pollen large, sub-triangular in polar view, oblate, isopolar, angulaperturate, 50 68 pm in equatorial diameter; apertures slightly asymmetric in distribution, tricolporate, minutely fossaperturate. Colpi about 12pm long, brevicolpate, generally closed, crassimarginate, bordered by closely spaced, thick and small rugulae; ora comparatively small, 5-8 pm in diameter, lalongate, heavily costate. Nexine distinctly thicker than sexine, almost uniformly thick in mesocolpia and slightly thicker around endoaperture. Mesocolpial sexine _+ uniformly thick while around the endoaperture it is slightly thickened, verrucate along mesocolpia, otherwise clearly rugulate, dupli-to pluribaculate. Specimens observed: 14 Comments: The heavy rugulate verrucate ornamentation and unequal distribution of apertures
289
readily differentiate this palynomorph from other described species of Lanagiopollis. It shows some resemblance to L. ruguloverrucatus Morley described from Middle to Late Eocene deposits of Central Java (Morley, 1982). However, the distribution pattern of apertures, the nature of colpi as well as the ornamentation pattern are quite different. In having a characteristic thicker nexine and overall peculiarity of sculpturing, this morphotype somewhat resembles the pollen of extant Alangium ebenaceum (Reitsma, 1970). This species has been named after Dr. T. Reitsma in recognition of his monographic contribution to the palynology of the Alangiaceae. Holotype: Plate III, 7,8, Slide No. Lig.-9/12 (S) Locality and age: Rajpardi lignite, Gujarat, India, Lower-Middle Eocene.
Lanagiopollis rugulatus sp. nov. (Plate IV, 1-5) Description: Pollen grains large, isopolar, triangular in polar view, oblate, angulaperturate, 62-70 pm in equatorial diameter, apertures slightly asymmetric in distribution, tricolporate. Colpi distinct, ca. 13 pm long, 8 10 pm wide at equator, almost brevicolpate; margin smooth, straight, thick, thicker around endoaperture, bordered by thick brochi, ends acute; ora distinct, circular to slightly elliptic, 10 12 pm in diameter, lalongate, heavily costate, margin incurved. Nexine is slightly thicker than sexine, gradually thinning towards aperture, but thickening again around the endoaperture, forming conspicuousely thick costa; sexine also is thicker in mesocolpia, gradually decreasing in thickness towards aperture and again increasing at the equatorial margin of colpi; apocolpial and mesocolpial sexine is prominently rugulate while around both sides of equatorial colpal margins it has a minute areolate appearance. Specimens observed: More than 50. Comments: The triangular shape, slight unequal
P L A T E I11 1 3. 4,5. 6. 7,8.
Lanagiopollis ruguloreticulatus sp. nov., holotype. Slide No. Lig.-9/2 (S). SEM photograph of the similar pollen. SEM photograph of L. reitsmae sp. nov. Lanagiopollis reitsmae sp. nov., holotype. Slide No. Lig.-9/12 (S).
290
N.R. P H A D T A R E A N D B T H A K U R
TABLE II Comparative morphology of various species of Lanagiopollis Morley
Taxa
Size in polar view (t-tm)
Ectoaperture Distribution
Length
Ornamentation
Reference
Equatorial width (/am)
( 1) Lanagiopollis regularix Morley (2) L. microrugulatus Morley (3) L. ruguloverrucalus Morley (4) L. nanggulanensis Morley (5) L. emarginatus Morley (6) L. ruguloreticulutus sp. nov. (7) L. reitsma sp. nov. (8) L. ruRulalus sp. nov.
67-78
Radially symmetric 1/2 the radius
Ca 5/am
Finely reticulate
Morley. 1982
68 73
Radially symmetNc 1/3 the radius
7 /am
Micro-eurugulate
Morley, 1982
ca.70
Radially symmemc 1/3 the radius
8 ~m
Rugulo-verrucate
Morley, 1982
75 105
Radially symmetmc 1/2 the radius
6 8 ~tm
Morley, 1982
60 85
Radially symmetric variable
10 p.m
55-70
Radially symmetric 16/am
8 10 gm
Coarsely rugulate to reticulate Eureticulate to eurugulate Rugulo-reticulate
50 68 62 70
Asymmetric Asymmetric
closed
Verrucato-rugulate
8-10/am
Coarsely rugulate
distribution of apertures and distinct coarsely rugulate ornamentation are the diagnostic features of this morphotype by which it can easily be distinguished from other species of Lanagiopollis. In gross morphology it resembles pollen of the section Conostigma. Holotype: Plate IV, 1-3; Slide No. Lig.-9/2 (S) Locality and age: Rajpardi lignite, Lower Middle Eocene.
Age of the Rajpardi lignite In dealing with the detailed stratigraphy of the Cambay Basin and a spatial comparison with that of the Jhagadia-Tarkeswar area in the east, Chandra and Chowdhary (1969) stated that the Tarkeswar Formation was unfossiliferous. Very recently however, a good fossil pollen population has been recovered from the lignite of the Tarkeswar Formation (Thakur and Phadtare, 1989). In the Jhagadia area, the "Nummulitic" fauna
12 gm 13 /am
Morley, 1982 Present work Present work Present work
(without the names of taxa being cited) of the underlying limestone was dated as Middle to Late Eocene (Chandra and Chowdhary, 1969, p.40). As it unconformably overlies the "Nummulitics", the Tarkeswar Formation was considered to be of Early Miocene age, possibly based on its spatial lithostratigraphic correlation with the Kathana Formation of the Cambay Basin. In the Rajpardi area, as the Nummulitic Formation is missing (Kathiara, 1968, p.2), the lignite of the Tarkeswar Formation unconformably overlies the Lower Eocene Vagadkhol Formation. Kathiara (1968) suggests that the Tarkeswar Formation is of Late Eocene to Oligocene age. The pollen/spore spectrum recovered from the Rajpardi lignite (Thakur and Phadtare, 1989 and the present study), in comparison with the palynostratigraphy of various other Tertiary deposits of India (Sah and Mehrotra, 1988), hint at a still older age of Early to Middle Eocene. Other faunal as well as stratigraphic evidence is essential to verify the age of the Rajpardi lignite.
PLATE IV I 3. Lanagiopollis rugulatus sp. nov., holotype. Slide No. Lig.-9/2 (S). 4,5. SEM photograph of the similar grain.
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Indian record of the fossil
N.R. P H A D r A R E A N D B. T H A K U R
Alangium
An examination of the palaeofloristic literature on the different Tertiary deposits of India reveals that amongst fossil angiosperm taxa so far reported, Alangium is perhaps the only genus convincingly documented by its almost all parts, viz., wood, leaves, pollen and possibly even fruits. The acceptable existing Indian record of fossil remains attributable to Alangium is abstracted in Table III.
Wood: The fossil wood of Alangium (Alangioxylon sclariformae Awasthi) is so far known from a single report from the Cuddalore Sandstone of South India (Awasthi, 1968). Having characteristic xylotomical features such as small- to medium-sized vessels with scalariform plates, 1 3 seriate long and heterogenous rays and the nonseptate fibres, it closely resembles the wood of extant Alangium javanicum (Awasthi, 1974) of the section Cono-
stigma. Leaves: The first Indian record of fossil leaf
TABLE Ill Fossil remains of Alangium from Indian Tertiaries Taxa Wood (1) Alangioxylon sclar(formae Leaf (2) Alangium salvi(folium Pollen (3) Tricolporopilites sp.* (4) Favitricolporites grandis
Affinity
Age
Area
Remarks
Section Conostigma
Eocene ?
Cuddalore sst.
Awasthi (1968)
Section Alangium
Miocene
Ratnagiri lignite
Dalvi and Kulkarni (1982)
Section Marlea ? Section Marlea
Assam Cauvery Basin Kachchh
Biswas (1962) Venkatachala and Rawat (1972) Kar (1985)
Kachchh Kerala
Kar (1985) Raha et al. (1986)
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Rajpardi lignite
Present work
Neyveli lignite Neyveli lignite Assam
Ramanujam (1966) Ramanujam (1966) Sah and Dutta (1968) Phadtare and Kulkarni (1983) Nandi ( 1981 ) Nandi (1981) Thanikaimoni et al. (1984)
(10) L. emarginatus
Section Conostigma
( 11) L. ruguloreticulatus
Section Conostigma
(I 2) L. rugulatus
Section Conostigma
(13) L. reitsmae
Section Conost~gma
(14) Margocolporites dubius (15) M. complexum (I 6) Favitricolporites complex
Section Marlea Section Marlea Section Marlea
Late Paleocene Early Eocene Early Miocene Early-Middle Eocene Early Eocene Early Middle Eocene Early-Middle Eocene Early-Middle Eocene Early-Middle Eocene Early-Middle Eocene Early-Middle Eocene Early Middle Eocene Eocene Eocene Oligocene
(17) Palaeoalangiumpollis zoniporatus
Section Alangium
Miocene
Ratnagiri lignite
(18) Ghoshiadites reticulatus (19) Foveotricolporites foveolatus (20) Ahmgium havilandii
Section Conostigma Section Marlea Section Conostigma
Miocene Miocene MiocenePliocene
Assam Assam Assam
(5) Tricolporopilites robustus*
Section Conostigma
(6) Pillicieroipollis langenheimii (7) Pillicieroipollis langenheimii
Section Conostigma Section Conostigma
(8) Pillicieroipollis langenheimii
Section Conostigma
(9) Lanagiopollis microrugulatus
Section Conostigma
*Awaiting confirmation.
FOSSIL POLLEN OF AL.4NGI(M
impressions attributed to extant Alangium (Marlea) was from the Pleistocene deposits of the Karewa Basin (Puri, 1953). Subsequently, VishnuMittre (1964) considered it as an ecologic misfit in a temperate flora. The distinctly dentate margin of these leaves (Puri, 1953, fig.6) certainly indicates that they do not belong to Alangium (Eyde et al., 1969). Well-preserved leaf compressions resembling extant Alangium have been reported from the Miocene lignite of Ratnagiri. Some of the leaves, in their epidermal characters such as paracytic stomata, unicellular and finger-shaped hairs confined exclusively to abaxial surfaces, etc., closely resemble Alangium salviffolium (L.) Wangerin, at present found in drier parts of plains and hilly tracts throughout India. Detailed comparative studies of the fossil cuticles and those of A. salviifolium (Dalvi and Kulkarni, 1982) confrm that during the Miocene, A. salviifolium was one of the common elements of the Western Ghat Flora. Fruits: The first collection of fossil fruits from lignite outcrops of the Ratnagiri area was made by Wilkinson (1871). Some of the fruits from his collection were provisionally identified by him as Terminalia. However, an extensive carpologic collection from different lignitic exposures of this area, indicates that a good number of fossil fruits closely resemble the extant Alangium in their morphology and anatomy (Kulkarni and Phadtare, unpublished work). Morphological features, such as 6 8 longitudinal ridges, size, shape and anatomical characters, viz., bilocular ovary, unequal carpel size, smaller carpel abortive and nature of stone cells, etc., exhibited by the fossil fruits are reasonably well comparable with A. platonifolium (Eyde et al., 1969). Since the fruits of different species of Alangium show a considerable overlap in their gross morphology and anatomy, a systematic study of the carpology of the family Alangiaceae will be the only way to confirm this affinity. Pollen: In comparison with megafossil remains, a very good pollen record of fossil Alangium is available from different Tertiary deposits of India. The first Indian report of fossil pollen directly comparable with extant Alangium is that of Palaeoalangiumpollis zoniporatus Phadtare and Kulkarni, (1983) recovered from the Ratnagiri
293
(Miocene) lignite of Maharashtra (Phadtare, 1982: Phadtare and Kulkarni, 1983). In its characteristic features such as its 4-6 zoniporate nature and very distinctly heterogemmate ornamentation, it closely resembles the pollen of Alangium salvfi['olium. Palynofloristic studies on the Tertiary (Matanomadh, Naredi and Harudi Formations) exposures of Kachchh (formerly spelled at Kutch) by Sah and Kar (1969) and Kar (1985) have documented plentiful pollen closely resembling those of the section Conostigma. Initially, it was reported from the Lower-Eocene Naredi Formation as Pellicieroipollis langenheimii Sah and Kar (1969). Subsequently, similar palynomorphs have also been recovered from near Lakhpat and Rataria (Kar, 1985). The natural affinity of this palynomorph was earlier suspected by Muller (1981), who stated that it could be comparable to Alangium pollen rather than that of Pelliciera. Muller's view was supported by Morley (1982) and further strengthened by Thanikaimoni et al., (1984). On reexamination of holotype preparations, it was observed that none of the pollen spedimens assigned to Pellicieroipollis show the generic character "negative reticulum" (= S-LO pattern). The close similarity between these fossil pollen grains and those of the section Conostigma (Morley, 1982) strongly indicate that during the Early Eocene the genus Alangium was well established in the Kachchh area. This is further supported by the report of P. langenheimii and different species of Lanagiopollis from the Rajpardi lignite deposit situated towards the southeastern side of Kachchh (Thakur and Phadtare, 1989). The presence of similar Alangium pollen in the EarlyEocene Naredi Formation and Rajpardi lignite of the Tarkeswar Formation, strongly indicates that both formations were deposited during the same geologic epoch. Along with Pellicieroipollis langenheimii and species of Lanagiopollis, other palynomorphs such as Proxapertites operculatus Van der Hammen, Lakiapollis ovatus Venkatachala and Kar, Dandotiaspora dilata (Mathur) Sah, Kar and Singh, Arengapollenites echinatus Kar, etc., have also been recovered from this lignite and this further supports the possibility that this lignite is of Early- to Middle-Eocene age. Another form-genus Tricolporopilites Kar with
296
closely comparable to those of the extant genus Alangium. These pollen grains have been systematically described under appropriate species of Pellicieroipollis and Lanagiopollis. The fossil records of Alangium suggest that the family Alangiaceae can reasonably be traced back to the Late Paleocene. The present data and a critical review of existing Indian literature on fossil Alangium lead to the following further inferences. (1) The section Marlea of the genus Alangium first appears in the Upper Paleocene of Assam. (2) Probably during the Early Eocene, members of the section Marlea become more widely distributed and extended into South India. In Assam, Marlea continued to thrive until the Miocene and during this epoch probably more than one member of the section Conostigma apeared. (3) The earliest appearance of the section Conostigma is evidenced by the various Eocene reports from South India. During the same period, it also spread over the Gujarat and Kachchh areas of Western India. (4) Alangium salviifolium, a member of the section Alangium, appears to have been introduced into the Indian subcontinent during the Middle Miocene.
Acknowledgements Authors are grateful to the Director, Wadia Institute of Himalayan Geology for his kind permission to carry out this research work. Financial assistance from D.S.T., the Government of India (Bengal Fan Project) is thankfully acknowledged. The informal co-operation, assistance and help extended by the Manager, Jhagadia Lignite Corporation (G.M.D.C. Gujarat State Government), Mr. R.D. Desai, Sr. Geologist and other official personnel during the field work is greatly appreciated.
References Awasthi, N., 1968. A new fossil wood belonging to the family Alangiaceae from the Tertiary of South India. Palaeobotanist, 17: 322-325. Awasthi, N., 1974. Neogene Angiospermous woods. In: Surange et ah (Editors) Aspects and Appraisal of Indian Palaeobotany. B.S.I.P. Lucknow, pp.341-358.
N.R. P H A D T A R E A N D B. T H A K U R
Banerjee, D., 1964. A note on the microflora from Surma (Miocene) of Garo Hills, Assam. Bull. Geol. Min. Metall. Soc. India, 25: 1-8. Biswas, B., 1962. Stratigraphy of the Mahadev, Langpar, Cherra and Tura Formation. Assam, India. Bull. Geol. Min. Metall. Soc. India, 25: 1-48. Bose, R.H., 1908. Note on the geology and mineral resources of Rajpipla state. Rec. Geol. Surv. India, 32:167 180. Chandler, M.E.J., 1964. The Lower Tertiary Floras of Southern England, 4. A summary and survey of findings in the light of recent observations. Br. Mus. (Nat. Hist), London, 151 p. Chandra, P.K. and Chowdhary, L.R., 1969. Stratigraphy of the Cambay Basin. Bull. Oil Nat. Gas Comm., 6(2): 34-50. Cookson, I.C., 1957. On some Australian Tertiary spores and pollen grains that extend the geological and geographical distribution of living genera. Proc. R. Soc. Victoria, 69: 41-54. Dalvi, N.S. and Kulkarni, A.R., 1982. Leaf cuticles from Lignitic beds of Ratnagiri Dist., Maharashtra. Geophytology, 12(2):223 232. Deb, U., Baksi, S.K. and Ghosh, A.K., 1973. On the age of Neyveli lignite - - a palynological approach. Quat. J. Geol. Min. Metall. Soc. India, 45(1): 23-38. Desikachar, S.V., 1984. Oil gas deposits in the delta sequence of sediments in Cambay basin and Upper Assam in India. J.Geoh Soc. India, 25(4): 199-219. Erdtman, G., 1952. Pollen morphology and plant taxonomy. I Angiosperms. Almqvist Wiksell, Stockholm. 539 pp. Eyde, R.H., Bartlett, A. and Barghoorn, E S., 1969. Fossil record of Alangium. Bull. Torrey Bot. Club, 96:288 314. Fairchild, W.F. and Elsik, W.C., 1969. Characteristic palynomorphs of the Lower Tertiary in the Gulf Coast. Palaeontographica B, 128: 81-89. Gadekar, D.R., 1975. Geology of Tertiary rocks of south Gujarat with special reference to their stratigraphy and sedimentation. Univ. Baroda, (unpublished Thesis). Gadekar, D.R., 1977. Sedimentary structures in the Tertiary rocks of South Gujarat and their environmental significance. J. Geol. Soc. India, 18:549 557. Kathiara, R.S., 1968. Lignite deposits in Bhuri area, Broach Dish. Gujarat. Mineral Wealth, 4(4): 12 16. Kar, R.K., 1979. Palynological fossils from the Oligocene sediments and their biostratigraphy in the distr, of Kutch, Western India. Palaeobotanist, 26(1): 16 45. Kar, R.K., 1985. Fossil flora of Kuchchh. Palaeobotanist, 34: ! -280. Kar, R.K. and Saxena, R.K., 1981. Palynological investigation of a bore core near Rataria, Southern Kutch, Gujarat. Geophytology, 11(2): 103-124. Krutzsch, W.. 1962. Stratigraphisch bzw, botanisch wichtige neue sporen-und pollen formen aus dem deutschen Tertiar. Geologie (Berlin), 11:265 307. Krutzsch, W., 1969. Uber einige stratigraphisch wichtige neue longaxoner pollen aus dem mitteleuropaischen Alttertiar. Geologie (Berlin), 18(4): 472-487. Moore, P.D. and Webb, J.A., 1978. An lllustrated Guide to Pollen Analysis. Hodder Stoughton, London. 133 pp. Morley, R.J., 1982. Fossil pollen attributable to Alangium Lamarck (Alangiaceae) from the Tertiary of Malesia. Rev. Palaeobot. Palynol., 36: 65-94.
295
FOSSIL POLLEN OF ALANGIUM
tricolporites foveolatus Nandi (Nandi, 1981, pl.2, figs.45,47; Thanikaimoni et al., 1984, figs.638-646) from the Late Miocene of Upper Assam are certainly pollen of Alangium. Fossil pollen grains closely comparable to those of Alangium havilandii Bloembergen are also present at the same locality (Thanikaimoni et al., 1984, figs.653-661). Stratigraphic antiquity The stratigraphic palaeogeography of Alangium in global perspective (Eyde et al., 1969; Reitsma, 1970; Muller, 1981 and Morley, 1982), is fairly clear due to the numerous fossil reports thereof from various countries, such as North America (Traverse, 1955), Europe (Krutzsch, 1962, 1969; Chandler, 1964; Pacltova, 1966; Fairchild and Elsik, 1969: Nagy, 1973), Africa (Puri, 1964), tropical islands of the Indian and Pacific Oceans (Cookson, 1957; Muller, 1964; Morley, 1982) and Japan (Sato, 1963). Its Indian stratigraphic history however, is much more dubious. The foregoing appraisal of the Indian records of fossil Alangium indicates that the monogeneric family Alangiaceae had a wide (Paleocene to Late Miocene) temporal geologic distribution. Amongst the Indian reports of fossil Alangium known and available in the literature, only those which are confirmed, accepted or reasonably acceptable have been considered. Upper Paleocene: The earliest appearance of fossil Alangium in the Indian sub-continent is from Assam. Tricolporipites sp. reported from the Cherra Formation (Biswas, 1962; p.37, pl.5, fig.3), being a synonym of the Favitricolporites complex Sah and Dutta (1968, p. 190), compares reasonably well with pollen of the section Merlea. If its alangiaceous affinity is confirmed, the earliest appearance of Alangium can be extended down to the Late Paleocene. Eocene: Following its first appearance in the Late Paleocene, the presence of Alangium in the Early Eocene of Assam is marked by the report of Favitricolporites complex Sah and Dutta (1968) from the Tura Formation. Favitricolporites grandis (Venkatachala and Rawat, 1972) representing the section Marlea, occurs in Lower-Middle Eocene sediments of the Cauvery Basin. Similarly, Margo-
colporites dubius and M. complexum from the Neyveli lignite (Ramanujam, 1966) have an alangiaceous affinity (Reitsma, 1970) and indicate the existence of a member of the section Marlea. Considering the Cuddalore Sandstone and associated lignite to be of Eocene age (Deb et a1.1973; Muller, 1981), the fossil wood resembling A.javanicum (Awasthi, 1974) marks the presence of a conostigmoid member. Different species of Lanagiopollis and P. langenheimii recovered from the Tarkeswar Formation of Gujarat and described in this communication, indicate a close affinity with pollen of the section Conostigma. Species of Pellicieroipollis (Sah and Kar, 1969; Kar, 1985) known from the Early to Middle Eocene of Kachchh confirm that members of the section Conostigma were growing profusely in the Gujarat and Kachchh areas. Oligocene: The fossil pollen described as Favitricolporites complex, Tetracolporites paucus and T. onagraceoides (Sah and Dutta, 1968) have many features in common with eureticulate forms of the section Marlea. This represents an acceptable Oligocene record of fossil Alangium from the Baragolai Formation in Assam. Miocene: The continuing presence of'Alangium in the Miocene sediments of Assam is evidenced by Favitricolporites foveolatus, representing the section Marlea [=A. griffithii (Clarke) Harms] and Ghoshiadites reticulatus resembling the pollen of A. nobile (Clarke) Harms from the section Conostigma (Thanikaimoni et al., 1984). Pollen very similar to that of A. havilandii is known from the Late Miocene to Pliocene of Assam and further indicates that, in addition to Marlea, possibly more than one member of Conostigma was thriving in Assam. In Western India, the report of Palaeoalangiumpollis zoniporatus (Phadtare and Kulkarni, 1983) and leaf cuticles (Dalvi and Kulkarni,1982) from the Middle-Miocene lignite of Ratnagiri confirm the presence of the section Alangium (= A. salviifolium) in Tertiary sediments of India.
Summary and conclusions Detailed palynological studies on the Eocene lignite of Gujarat reveal an abundance of pollen
FOSSIL POLLEN OF ALANGIUM
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