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A 530 year long record of the Indian Summer Monsoon from carbonate varves in Maar Lake Twintaung, Myanmar
Author(s) -
Sun Qing,
Shan Yabing,
Sein Kyaing,
Su Youliang,
Zhu Qingzen,
Wang Luo,
Sun Jiming,
Gu Zhaoyan,
Chu Guoqiang
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2015jd024435
Subject(s) - maar , varve , monsoon , climatology , geology , precipitation , carbonate , arid , environmental science , atmospheric sciences , sediment , geomorphology , geography , paleontology , volcano , materials science , meteorology , metallurgy
We report an annually laminated sequence spanning the past 530 years from Maar Lake Twintaung, Myanmar. Calcareous varves appear as rhythmic units of light‐colored carbonate and dark‐colored biogenic‐clastic lamina in the sediment. The light‐colored carbonate layers are formed in the dry season due to strong evaporation and Spirulina blooms. The varved sequence provides a high‐resolution geochemical archive of paleoclimatic variability in this tropical, data sparse area. A synchrotron radiation X‐ray fluorescence method was used to analyze elemental data at seasonal to annual time scales. In this arid region, elemental Ca and Sr are mainly regulated by the balance of evaporation and precipitation in this closed lake basin. The elemental variations show distinct interannual and decadal variabilities. On interannual time scales, spectral analysis of the Ca and Sr time series indicates stronger El Niño–Southern Oscillation (ENSO)‐like (Indian Ocean Dipole (IOD)‐like) variability at periods of 2–7 years. It may suggest that ENSO and/or IOD are two dominant modes of regional rainfall variability on interannual time scales over the past 530 years. The quasiperiodicities of approximately 10 years suggest that solar activity may be a critical driving force of monsoonal rainfall in the region. A notable feature is that decreasing monsoonal rainfall since A.D. 1840 is coupled with tropical sea surface temperature variation. Considering that the monsoonal rainfall is coupled with several atmospheric processes evolving at different spatial and temporal scales, more high‐resolution data are required to evaluate and verify the regional rainfall variability and its dynamic links.