An Encyclopaedia of Indian Archaeology v1.c12.s3.4

v1.c12.s3.4

The climatic changes are generally ascribed to the changes in the eccentricity of the earth’s orbit, obliquity of the axis and precession of the equinoxes, and to some extent to the ‘sun-spot cycle’. Recent searches on the marine sediments do reflect periodicities of 23000 years (corresponding to precession index), 42000 years (obliquity of the axis) and 100000 years (orbital eccentricity) which have given added support to Milankovitch’s original astronomical theories of climatic change. Considerable controversies however still exist in this field.