An Encyclopaedia of Indian Archaeology v1.c12.s4.5

v1.c12.s4.5

Phase I, before 8000 B.C., stratigraphically determined, is representative of severe arid environments under which the sand-dunes, now stabilized, are suggested to have been active. The period generally corresponds in time to at least the latter part of the Last Glacial in the Himalayas and is considered to have been extremely unsuitable for human habitation in Rajasthan. The conditions changed dramatically at the beginning of Phase II, 8000-7500 B.C., as shown by the infilling of large and small inland drainage basins with freshwater and the resulting deposition of lacustrine sediments. The date of this change coincides with the Late Weichselian/Flandrian boundary of w. Europe. The improvement in the availability of freshwater opened up possibilities of human migrations into the area. The vegetation comprised an openland steppe which was rich in grasses, *Artemisia* and sedges but poor in halophytes. *Artemisia, Typha angustata* (bull-rush), *Mimosa rubicaulis* and *Oldenlandia*, which now grow under areas of comparatively high average annual rainfall (above 500 mm), flourished in the semi-arid belt, while the first-two plant taxa had encroached even as far as the arid belt (100 to 250 mm mean annual rainfall), both suggesting that a general westward shift of the rainfall belts had taken place. Vegetation destruction through burning by man is suggested to have started together with the first occurrence of Cerealia-type pollen at about 7500 B.C. and continued thereafter throughout Phases III and IV. The increase in swamp vegetation and the intensification of vegetation cover inland together with the maxima of all mesophytic elements, including *Syzygium cuminii, jamun*, in Phase IV, c. 3000-1000 B.C., indicate an increase in rainfall. However there was a short relatively dry time about 1800-1500 B.C., and only a marginally wet period between 1500-1000 B.C., at Sambhar which coincides with the decline of the Indus culture [4.9] in n.-w. India. Between Phases IV and V there is a hiatus in the pollen preservation and at the same time there is stratigraphic evidence that the salt lakes started drying. At Pushkar there is evidence that the vegetation showed a marked change to a drier plant assemblage in the Aravallis. The onset of this aridity seems to have been widespread. The climate did not ameliorate until Phase V, early centuries A.D. to the present, at which time the RANG MAHAL culture the remains of which imply good water supply flourished in Rajasthan. The amelioration since the onset of aridity, however, has been small and has not led to any significant change in the overall climate of w. Rajasthan.