An Encyclopaedia of Indian Archaeology v1.c14.s2.10

v1.c14.s2.10

About this time Gurdip Singh carried out palynological studies in Lunkaransar, Didwana, Sambhar and Pushkar lakes [7.4] and propounded the following climatic sequence for end-Pleistocene and Holocene times: Phase I, before *c.* 10000 B P., arid climate, formation of sand-dunes. Phase II, *c.* 10000 to *c.* 9500 B.P., wet climate, formation of lakes, rainfall at least 25 cm more than present. Phase III, *c.* 9500 to *c.* 5000 B.P., slight decline in rainfall but freshwater lakes persist. The appearance of Cerealia-type pollen and considerable rise in carbonized vegetable remains in lake sediments is interpreted by him as suggesting the burning of vegetation by man for slash-and-burn agriculture. And Phase IV, *c.* 5000 to *c.* 3000 B.P , divisible into three sub-phases, IVa (*c.* 5000 to *c.* 3800 B.P.), IVb (*c.* 3800 to *c.* 3500 B.P.) and IVc (*c.* 3500 to *c.* 3000 B.P ). During sub-phase IVa rainfall increased considerably, being about 50 cm higher than at present. This period saw the emergence of pre-Harappa and Harappa civilizations in n. Rajasthan, and Singh believes that increased precipitation was one of the causative factors in this sudden cultural efflorescence. After 3500 B.P. rainfall began to decline and by about A.D. 1000 the present-day arid conditions were established.