A 8400-year pollen records of vegetation dynamics and Indian Summer Monsoon climate from central India: Signatures of global climatic events

摘要

Pollen analytical study of a 2.1-m deep lacustrine sedimentary profile from central India has demonstrated that between similar to 8400 and 1200 cal yr BP, open, mixed tropical, deciduous forest occurred in the region under a warm and moderately humid climate, probably indicating moderate monsoon precipitation. Subsequently, between similar to 1200 and 500 cal yr BP (AD 750-1450), with the spread of most of the existing forest constituents, the open, mixed tropical, deciduous forest was succeeded by dense mixed, tropical, deciduous forest owing to the prevalence of a warm and humid climate with increased monsoon precipitation, coinciding with the Medieval Warm Period (MWP)/ Medieval Climate Anomaly (MCA) (AD 750-1200). Finally, during similar to 500 cal yr BP (AD 1450) to the Present, mixed, tropical, deciduous forest has been replaced by a relatively denser, mixed, tropical, deciduous forest around the study area under a warm and relatively more humid climate with further increase in monsoon precipitation, which falls within the time-frame of the Current Warm Period (CWP) (AD 1800 to the Present). Moreover, the varying degrees of warming since similar to 8.4 ka to the Present could be correlatable with the Holocene Climate Optimum (HCO)/Holocene Thermal Maximum (HTM). The present study provides insights into the vegetation dynamics and Indian Summer Monsoon (ISM)-influenced climate since the last similar to 8.4 ka to the Present from one of the poorly understood areas of the tropics where rainfall is essentially controlled by the monsoon [especially the southwest (summer) monsoon; SWM/SM] variability.