title: Oxygen isotope in archaeological bioapatites from India: Implications to climate change and decline of Bronze Age Harappan civilization.
abstract: The antiquity and decline of the Bronze Age Harappan civilization in the Indus-Ghaggar-Hakra river valleys is an enigma in archaeology. Weakening of the monsoon after ~5 ka BP (and droughts throughout the Asia) is a strong contender for the Harappan collapse, although controversy exists about the synchroneity of climate change and collapse of civilization. One reason for this controversy is lack of a continuous record of cultural levels and palaeomonsoon change in close proximity. We report a high resolution oxygen isotope (δ(18)O) record of animal teeth-bone phosphates from an archaeological trench itself at Bhirrana, NW India, preserving all cultural levels of this civilization. Bhirrana was part of a high concentration of settlements along the dried up mythical Vedic river valley 'Saraswati', an extension of Ghaggar river in the Thar desert. Isotope and archaeological data suggest that the pre-Harappans started inhabiting this area along the mighty Ghaggar-Hakra rivers fed by intensified monsoon from 9 to 7 ka BP. The monsoon monotonically declined after 7 ka yet the settlements continued to survive from early to mature Harappan time. Our study suggests that other cause like change in subsistence strategy by shifting crop patterns rather than climate change was responsible for Harappan collapse.
authors.affiliation: Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721302, India.
authors.forename: Anindya
authors.initials: A
authors.lastname: Sarkar
authors.affiliation: Deccan College Post Graduate and Research Instiute, Pune 411006, India.
authors.forename: Arati Deshpande
authors.initials: AD
authors.lastname: Mukherjee
authors.affiliation: Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721302, India.
authors.forename: M K
authors.initials: MK
authors.lastname: Bera
authors.affiliation: Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur 721302, India.
authors.forename: B
authors.initials: B
authors.lastname: Das
authors.affiliation: Physical Research Laboratory Navrangpura, Ahmedabad 380009, India.
authors.forename: Navin
authors.initials: N
authors.lastname: Juyal
authors.affiliation: Birbal Sahni Institute of Palaeosciences, Lucknow, India.
authors.forename: P
authors.initials: P
authors.lastname: Morthekai
authors.affiliation: Physical Research Laboratory Navrangpura, Ahmedabad 380009, India.
authors.forename: R D
authors.initials: RD
authors.lastname: Deshpande
authors.affiliation: Deccan College Post Graduate and Research Instiute, Pune 411006, India.
authors.forename: V S
authors.initials: VS
authors.lastname: Shinde
authors.affiliation: Archaeological Survey of India, Nagpur, 440006, India.
authors.forename: L S
authors.initials: LS
authors.lastname: Rao