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, delta C-13 values, TOC, TN, TOC/TN, and magnetic susceptibility (chi(lf)) 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 delta C-13 values, TOC/TN ratio, and magnetic susceptibility (chi(lf)) from similar to 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 C-4 plants during similar to 8.1 and 6.3 ka BP, similar to 6.3 to 4.7 ka BP, and similar to 3.0 to 2.0 ka BP suggests a gradual weakening of ISM. The highest delta C-13 values (-18.7 parts per thousand) recorded at similar to 2.0 ka BP indicate the dominance of C-4 plants suggesting the weakest phase of ISM in the study area. The expansion of C-3 plants from similar to 2.0 to 1.6 ka BP indicates a sudden increase in ISM intensity. Subsequently, three stages of enhanced ISM have been recorded between similar to 1.6 and 0.93 ka BP, similar to 0.76 and 0.42 ka BP, and similar to 0.28 ka BP to present.