Indian summer monsoon variability and vegetation changes in the core monsoon zone, India, during the Holocene: A multiproxy study

We present the results of sediment texture, δ13C values, TOC, TN, TOC/TN, and magnetic susceptibility (χlf) of a 1.54-m deep sediment trench recovered from the core monsoon zone (CMZ) of central India, to understand the paleovegetational history and Indian summer monsoon (ISM) variability during the Holocene. The lower δ13C values, TOC/TN ratio, and magnetic susceptibility (χlf) from ~11.4 to 9.5 ka BP suggest enhanced ISM intensity, which is well correlated with other available ISM records from both terrestrial as well as marine archives. A gradual stepwise expansion of C4 plants during ~8.1 and 6.3 ka BP, ~6.3 to 4.7 ka BP, and ~3.0 to 2.0 ka BP suggests a gradual weakening of ISM. The highest δ13C values (–18.7‰) recorded at ~2.0 ka BP indicate the dominance of C4 plants suggesting the weakest phase of ISM in the study area. The expansion of C3 plants from ~2.0 to 1.6 ka BP indicates a sudden increase in ISM intensity. Subsequently, three stages of enhanced ISM have been recorded between ~1.6 and 0.93 ka BP, ~0.76 and 0.42 ka BP, and ~0.28 ka BP to present