A high-altitude calibration set of modern biotic proxies from the Western Himalaya, India: Pollen–vegetation relation, anthropogenic and palaeoclimatic implications
2022
Kar, Ratan | Mishra, Kriti | Firoze Quamar, M. | Bajpai Mohanty, Ruchika | Agrawal, Shailesh | Tripathi, Swati | Kumar Mishra, Amit
We analysed the pollen composition, non-pollen palynomorphs (NPPs) and stable carbon isotope data (δ¹³C values) of surface sediments (soil), from the proglacial deposits (outwash plain and the two levels of kame-terraces) of the Chorabari Glacier, Kedarnath, India. The main objective was to develop the modern-proxy analogues, for the calibration of fossil records, for use in palaeoclimatic reconstructions. The pollen–vegetation relation is incompatible (non-linear) with the present vegetation, as the pollen assemblages are marked by the prolific over-representation of extra-local pollen, especially Pinus, over the local herbaceous taxa. Multivariate principal component analysis (PCA) was applied on the palynological data to ascertain the major groups of pollen in relation to the vegetation types and reveal variations in the pollen records between the kame-terraces and the outwash plain. δ¹³C values of the soil organic matter (SOM) show an average of − 27.0‰, indicating a C₃ dominant vegetation. The pollen records have also revealed the anthropogenic activities in the form of degradation of tree-line and over-grazing by the domesticated animals. The NPPs reflect the prevalence of grazers in the present times, and would be useful in tracing the advent and intensification of grazing in the region. The modern pollen analogues show a good correlation with the fossil pollen data. The present study provides the much needed modern biotic analogues for vegetation-based past climatic reconstructions from the alpine regions of the Western Himalaya.
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