Asynchronous Variation of Indian Monsoon and East Asian Monsoon:Evidence from High-Resolution Oxygen Isotope Records of Laminated Speleothems

Indian Monsoon and East Asian Monsoon are two sub-systems of Asian Monsoon.A common pattern between the two monsoons at the seasonal and orbital time scales was formulated from the meteorological data and geological records.However,the relationship of the two sub-systems on the inter-annual and inter-decadal scales remains quite obscure.In this study,high-resolution oxygen isotope compositions of two laminated speoleothems from the Defore Cave of Oman and the Heshang Cave of China were compared with each other to detect the link between the Indian Monsoon and the East Asian Monsoon.δ18O of Defore stalagmite is characteristic of the Indian Monsoon while δ18O of Heshang stalagmite is an indicator of the East Asian Monsoon.Two stalagmite records show similar structures for the last 780 years on the decadal scale,implying the asynchronous variation of the Indian Monsoon and the East Asian Monsoon.