Indian monsoon variations during three contrasting climatic periods: The Holocene, Heinrich Stadial 2 and the last interglacial–glacial transition

Abstract

In contrast to the East Asian and African monsoons the

Short communication: Massive erosion in monsoonal central India linked to late Holocene land cover degradation

“…2). Pollen from the same core (Zorzi et al, 2015) reinforces these conclusions: coastal forest and mangrove pollen (Fig. 2) that are typical for the more humid coastal regions (Zorzi et al, 2015) and leaf-wax carbon isotopes of the Eastern Ghats and Godavari Delta declined over the Holocene.…”

“…Given the drastic changes in vegetation cover and increase in erosion in the Godavari Basin, a decrease in soil turnover is unlikely during the Holocene aridification process (Carvalhais et al, 2014). In turn, the good agreement between the pollen and leaf-wax δ 13 C records in our core Zorzi et al, 2015) with independent monsoon reconstructions suggests sustained delivery of recently fixed biospheric organic carbon to the delta. Thus, the doubling in age offset over the Holocene is best explained by increasing contributions from an older soil component, which could only come through deeper erosion.…”

“…Dryness-adapted thornbush pollen from the Deccan Plateau increased substantially after the second aridification step ∼ 1700 years ago, overlapping well with the maximum contribution of C 4 plant-derived leaf waxes (see Zorzi et al, 2015). For the same time interval, the ice-volume-corrected oxygen isotopic composition of planktonic foraminifer Globigerinoides ruber documented a series of low values interpreted as high-salinity events at the Godavari mouths (see Ponton et al, 2012).…”

“…We have previously reconstructed the Holocene paleoclimate using the same sediment core discussed herein Zorzi et al, 2015). Terrestrial reconstructions were based on the carbon isotopic compositions of higher plant leaf-wax biomarkers (i.e., long-chain n-alkanoic acids C 26−32 ) and pollen, whereas contemporaneous sea surface paleoceanographic conditions in front of the Godavari Delta came from the oxygen isotopic composition of planktonic foraminifer Globigerinoides ruber.…”

Link between Indian monsoon rainfall and physical erosion in the Himalayan system during the Holocene

“…The seasonal change in the wind direction generates a reversal of surface currents in the Bay of Bengal, which shift from a cyclonic gyre during the winter monsoon to an anticyclonic gyre during the summer monsoon [e.g., Unger et al ., ; Chauhan and Vogelsang , ] (Figure ). Numerous studies have provided insights into the evolution of the Indian summer monsoon intensity over the Indian subcontinent, the Tibetan plateau, and the Himalayas through the Holocene [e.g., Gasse et al ., ; Kudrass et al ., ; Dykoski et al ., ; Berkelhammer et al ., ; Cai et al ., ; Marzin et al ., ; Contreras‐Rosales et al ., ; Sarkar et al ., ; Zorzi et al ., ]. It is now well demonstrated that large‐scale Indian monsoon rainfall changes are mainly forced by low‐latitude summer solar radiation, which was responsible for changes of thermal contrasted between land and sea [e.g., Prell , ; Prell and Kutzbach , ; Clemens and Prell , ].…”