POLLEN ANALYSIS OF FOSSIL SOILS ALONG THE BANK OF GHOD RIVER, INAMGAON, MAHARASHTRA* VISHNU-MITTRE & H. P. GUPTA Birbal Sahni Institute of Palaeobotany, Lucknow-226007 ABSTRACT sonal nullahs. It is largely black cotton Pollen analysis of fossil soils along the bank of soil though sandy deposits are nQt infre• Ghod Rivet, Inamgaon, Maharashtra, suggests the quent. former occurrence of a dry deciduous forest domi• Thi.s pa.!t of district Pune is highly arid. nated by Holoptelea integrijolia. The annual pre• No clImatIc data are available for Inamgaon cipitation then was not higher than now and an environment of unstability of soil concentration or for any station in the immediate vicinity. along the banks had prevailed. The subfossil soils Pune has mean annual rainfall around 600 were formed by ponding of flood waters when the mm with only 47 rair,y da.ys in a year and water level in the river had risen much higher 58 per cent humidity. The mean annual than at the present caused probably by tectonic movement in the catchment area. temperature ranges frem 18°C to 32°C with The percentage distribution of pore apertures on th~ highe"t recorded around 43°C. Being subfossil pollen grains of Holoptelea integ,'ijoha has d.ner than Pune, the mean anual precipita• been found to differ considerably from the modern tIon at Inamgaon and vicinity is less than plants of this species suggesting a physiological change in the modern plants. 500 mm (pers. information Mr. Kajale of D.eccan ~ollege, Poona) and temperatures slightly hIgher than obtained at Pune. INTRODUCTION STRATIGRAPHY OF FOSSIL SOILS the occurrenceright Ibankof offo~silGhodsoilsriver,alonga THEtributary of the Bhima RiYer was The fossil soils occur along the right bank first discovered l.y Lala Aditya Narayan, of Ghod river in the form of bands of dark an archaeologist attached to ,the team of black clay extending over a short distance Prof. H. D. Sankalia excavating a Central of about It m. There are three prominent Indian Chalcolithic site, Inamgaon, about bands measuring about 7-21 Cmin thiCkness 1·60 km distant and upstream from the·right alternating with thin bands of sand or silt bank of the tributary. The attention of in between. The section comprising the the senior author to these fossil soils was ~ands of clay~ intercalated with sand layers drawn kindly by Prof. H. D. Sankalia during hes over a thm layer of brown sand resting his visit to Ir.amgaon in Feb. 1969. The on highly ferruginous boulder gravel about site is about 90 km di~,tant from Pune, 21 cm of which is exposed, and is overlain district Pune, Maharashtra. by about 1'20-1'50 m sand making the top Inamgaon lies in the dry arid region bear• of the bark. The boulder gravel i~ about ing patches of the Southern Tropical Thorn J ·50-~·50 m high from the river bed. Forest cO'mprising open low communities The top layer of black clay, about J 5-20 in which Acacia, Prosopis spp. and the other cm in thickne"s, was highly weathered and thorny hard wood species predomina·te. penetrated by rootlets of vegetation' growing Trees of ZizyPhus and Anogeiss1,f,s latifolia, over the bank. The middle laver telow Soymida febrifttga and shrubs of Capparis ab.out 20-~5 cm of sand layer, consisted of spp .. occur scattered in various preportions. thm bands of black clay alternating with Fleshy Euphorbias are not very infrequent. fine banes of silt or sand. The bottommost The trees are stunted with short boles and layer of black clay resting on a thin layer low crowns. Species of Aristida and Hete• of brown sand of about 3-6 cm in thickness ropogon contortus are the prominent grasses. was about 7-10 Cm thick. The brown sand Clumps of Typha occur in and around sea- overlay the boulder gravel. *Pollen analyses by H. P. Gupta; text and interpretation by Vishnu-Mittre. 72 Pages 73-7"- M 0 POLLEN ANALYSIS OF' BLACK CLAY EXPOSED IN A SECTION • • • • • ALONG RIGHT BANK OF GHOD RIVER, INAMGAON, • • MAHARASHT RA . • • • • • POONA" • • • • •• • • • • • • • • • SAND • • • • • • • • • • • • •• • • • • • • • • • I 1111111111111111_ • III ~ •. III I .:.:~.~ ,I •I ':::' '.:,: :-::::'.\::.:.: :;'.':',", :;' :.:.: :; ;'.: ~ I '--':"'.1. :.:.::.:.:.:.:.:.::.: ::::':. S.NO.4 • ,.~ ... _SN05----' - I 111111111111111 I - .... • • •• ~1il~~S~M~£ No7 o 5 10 15 20 25 30 35 40 45 50 55 60 65 70 o 0 0 10 0 0 0 0 0 0 0 0 0 0 10 5 5 1 LLI 1 1 -' III I I J 2 I I I 1 I I 1 I I III 1 I .L.L 1 1 1 J L..tUI I uuuuU,LJULJUI 1 UJ o 5-PORATE <{ UJ BROWNSAND FERRUGINOUS HOLOPTELEA LLI <{ w <> UJ lID 4 - PORATE <{ BOULDER GRAVEL <{ <> w ..J <l u.s w uJ LaJ • 3-POF\ATE uJ ~ ..J <{ <{ <> - <{ ~ <{ W <{ <l :::> >- 0 r- UJ ~ uJ W UJ <{ Z <{ LLI Z ::I: 0 (.) Z U <> UJ (.) - n. n.. en <{ <{ uJ <{ <{ <l 0 ~ 0 0 Z - 0 0 <> ~ Z <> cr r- -() .J en >- Z Q.. - <{ uJ ~ a: - <1: ~ ~ >- < n.. > a: UJ ..J .J Q.. <{ >- < <{ ::I: a:: -...J ~ <1: 0 0 0 >- a: ~ n.. ,,-. u <> U ::::l 0- (/1 -l 0 C' -&--... -------' - --', ------------- TEXT-FIG. 1 VISHNU-MITTRE & GUPTA - POLLEN ANALYSIS OF FOSSIL SOILS 75 A thorough search was made both up and discovered in every house excavated (Indian downstream along both the banks of the Archaeology-A Review, 1969-70). river to discover similar exposures of fossil soils, but the search proved fruit• less. POLLEN ANALYSIS The black clay bands in the section appear Text-fig. 1 to have been formed by ponding of water after an intermittent flooding episode causing No samples for analysis were collected the deposition of silt and clay repeatedly from the top layer of the fossil soils. for it over one another when the water level in was found much weathered and penetrated the river must have risen about 3·50 m above by rootle1s. The middle layer was com• the present river level. The overlying thick pe.ratively less weathered ar:d the bottom deposit of sand must have depo8ited by layer the le;:,st. Two to three samples each another flooding episode of more severe in vertical series were collected from the nature than the one preceding it. *A C14 middle and the bottom layers. date (TF-1003, 21725 ± m i.e. 19775 B.C) The samples were subjected to usual of shells from a pebble conglomerate oc• chemical treatment involving the use of curring about 2 m above the modern bed HF and suhsequently acetolY8is after Erdt• of the Ghod river reveals that the formation man (1943). All the samples from the of these black clay layers is subsequent to middle layer and the One from the bottom 20,000 years B.C. layer did not yield sufficient pollen for the The ferruginous boulder gravel appe8.rs construction of pollen spectra. The details to be the top of the pebble conglomerate (based upon percentages of each individual and both the gravel and the conglomerate calculated on the number of pollen grains are highly suggestive of the first major flood• of all land plants) of the two pollen spectra ing phase here. The last flooding phase from sample nos. 4 and 5 belonging to the which tended to deposit the top sand de• bottom layer are set agair:st stratigraphical posit may be of early historical times 2.S profile in text-fig. 1. evidenced by the embankment remains of Pollen Spectra - The two spectra are boulders set in hard mortar towards the dominated by pollen of Holoptelea integri• west of the Chalcolithic site, Inamgaon. folia, of which the pollen grains are 3-5 porate These flooding episodes resulted in alteration as contrasted from 4-6 porate in modern of the river course as is evidenced by the plants of this sepcies reported by Rhandelwal occurrence of a river channel running close and Vishnu-Mittre (1974). The percentage to the embankment which diverted the distribution of pores on pollen of modern and floodwaters in a NfS direction. From the subfos8il H oloptelea integrifolia also differs above it would appear that the formation considerably as shown in table-l below. of the black layers took place during the receding phase of the last Pluvial or sub• sequent to it. TABLE 1- PERCENTAGE DISTRIBUTION OF PORES ON POLLEN GRAINS OF Early Stone Age man was witness to the MODERN AND SUBFOSSIL HOLOPTELEA major flooding episode as stone tools of this INTEGRIFOLIA age have been recovered from the gravel deposits opposite Inamgaon together with NUMBER OF24'2%69'8%22'6%Sample6'0%74'6%No.SUBFOSSILPOLLEN542'6%40'8%16'6%MODERNPOLLEN2'8% remains of Bos4-poratt'5-porate6-poratenamadicus. PORESThe regionNo.has4 Sample been inhabited 3-porateby man since then as evi• denced by the large factory site probably of Late Stone Age near Inamgaon and by the Malwa and the Jorwe cultures dated from 1600 to 1000 B.c. Deer was the most hunted animal here during the central Indian Chalcolithic Culture as its bones have been *The other date for shells from Middle Stone Pollen erains of Syzygium vary from 0·48• Age tools bearing sandy pebbles 2m above the river bed is TF-ll77, 19290 ± 360 i.e. 17340 B.C. to 2·75 per cent indicating long distar.ce (Agrawal & Kusumagar, 1975, p. 150) transport. A single polyad of Acacia has 76 THE PALAEOBOTANIST been met with only in sample no. 4 indicat• in the very moist Teak forest (rainfall ing its loc3.1origin. Pollen grains referred over 2500 mm).