Sprecher
Beschreibung
A maiden multiproxy investigation of a 100 cm exposed sedimentary succession from the Garamur wetland, Majuli Island (Assam), was carried out to reconstruct climate–vegetation interactions and fluvial dynamics spanning the last ~5700 cal. yrs. BP. The earliest phase (5689–4687 cal. yrs. BP) is characterized by abundant arboreal pollen, freshwater diatoms (Aulacoseira, Eunotia), fine-grained sediments, and enrichment of Al₂O₃, Fe₂O₃, and TiO₂, strong terrigenous influx, and robust monsoonal conditions under a warm-humid climate, corresponding to the later phase of Holocene Climatic Optimum (HCO). Between 4687 and 4179 cal. yrs. BP, dominance of herbaceous, aquatic, and marshy taxa with sandy clay horizons reflects an active floodplain setting, while the presence of moderate arboreal pollen suggests preservation constraints under high-energy depositional conditions. The interval between 4179 to 2966 cal. yrs. BP records fluctuating climate and vegetation, marked by coarser sediments and increased extra-regional and aquatic pollen taxa. The climatic conditions remained warm but relatively less humid, with alternating wet-dry phases and are interpreted as a fluctuating floodplain regime, punctuated by intermittent dryness. From 2966 to 1655 cal. yrs. BP, increased floral diversity and cultural pollen taxa point to growing anthropogenic influence, coinciding with the Roman Warm Period (RWP), while fine sediments and elevated SiO₂ suggest relatively stable conditions. Between 1655 and 601 cal. yrs. BP, renewed arboreal expansion, clay-rich sediments, increased Aulacoseira, and higher cultural pollen indicate strengthened monsoon conditions during the Medieval Climatic Anomaly (MCA) alongside intensified human activity. This study highlights Mid–Late Holocene climate–vegetation coupling in the Brahmaputra Valley.