Reconstruction of Indian monsoon precipitation variability between 4.0 and 1.6 ka BP using speleothem δ¹⁸O records from the Central Lesser Himalaya, India

The present study documents the monsoon precipitation variability spanned ~ 2500 years, between 4.0 and 1.6 ka BP (before 1950 AD), from the Central Lesser Himalaya, India, using δ¹⁸O measurements of Tityana cave stalagmite (hereafter referred as TC1). At present, the cave receives precipitation from both Indian Summer Monsoon (ISM) and Western Disturbances (WDs). The δ¹⁸O variation between − 8.04 and − 10.46‰ through growth axis of the TC1 and five ¹⁴C AMS dates (due to large age uncertainty by ²³⁰Th/U method) have allowed us to identify the mid to late Holocene multi-decadal to centennial scale climatic oscillations. The higher δ¹⁸O values indicate the weakening of the monsoon precipitation, while the lighter values represent the stronger monsoon precipitation strength. Based on the fluctuations in δ¹⁸O values, three distinct phases of the precipitation variability are distinguished as, declined/decreased precipitation between ~ 4.0 and 3.4 ka BP with peak aridity around ~ 3.4 ka BP, followed by slightly improved conditions from ~ 3.4 to ~ 2.7 ka BP. Subsequently, the climate was reduced from ~ 2.7 ka BP onwards until the end of stalagmite growth, around ~ 1.6 ka BP with spikes of two major drought events centred at ~ 1.9 and ~ 1.6 ka BP. In general, the droughts, centred at ~ 3.4, ~ 1.9 and ~ 1.6 ka BP, are characterized by abrupt drop (from − 8.12 to − 8.04‰) in the δ¹⁸O values and point to the weakening of the monsoon. One of the major drought events at ~ 3.4 ka BP can be correlated with the collapse of the Indus valley civilization in the NW India. A close correspondence of the TC1 data set with other WDs influenced regimes likely indicates a relative impact of mid-latitude WDs after transition of the mid-late Holocene around 3.5–3.4 ka BP.