Middle to Late Holocene climate, vegetation and sea-level changes in NW Tripura, northeast India, based on palynological and mineral magnetic evidence

Mehrotra, Nivedita; Shah, Sameena; Basavaiah, N.; Kar, Ratan

doi:10.1007/s10933-022-00249-6

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…Ghosh et al (2015) has also suggested weak monsoon from the foothills of Darjeeling during 4.3 to 3.5 ka (Figure 9). Likewise, a sharp decline in precipitation regime is well observed at ~4 ka corresponding to 4.2 cooling event in various parts of north-east India (Bera and Basumatary, 2013; Ghosh et al, 2014; Mehrotra et al, 2022; Figure 9). Kotlia and Joshi (2013), based on geochemical parameters, major elements, chemical index of weathering (CIW) and loss-on-ignition (LOI), suggested reduced rainfall (unfavourable climate) between ~5.1 and 3.5 ka from the Garhwal Himalaya, which they correlated with the global 4.2 ka arid event.…”

Section: Discussionmentioning

confidence: 75%

Vegetation diversity in response to monsoonal variability in the Eastern Himalaya, India over the past ~13 000 yrs

Dubey,

Ali,

Quamar

et al. 2024

The Holocene

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Monsoon precipitation plays a crucial role in shaping the diversity of vegetation in the Himalayas, both in terms of temporal and spatial distribution. While palynology has traditionally been employed to reconstruct the past climate of the Himalaya, there has been limited understanding of how monsoon-related changes affect the structure and distribution of vegetation. To address this, we analysed pollen data from a 3 m deep sedimentary profile in the higher Sikkim Himalaya to reconstruct monsoon driven changes in vegetation diversity. Our results show a highly fluctuating trend of pollen and diversity parameters at late-Pleistocene-Holocene transition for which fluctuating hydroclimatic conditions and differential pollen preservation in coarser sediments is attributed. During the Early Holocene (10,438–7934 cal yrs BP) favourable hydroclimatic conditions led to a rapid expansion of mixed broad-leaved forests, marked by higher values of richness and alpha diversity. Between 7934 and 5481 cal yrs BP, the region experienced moderate hydroclimatic conditions that facilitated expansion and diversification of woody taxa, and correlated with the global Holocene Climate Optimum (HCO). Conversely, from 5481 to3949 cal yrs BP, declining total pollen count (TPC), species richness, and alpha diversity indicates significant shifts in vegetation composition under deteriorating climatic conditions, which corresponds with the 4.2 ka event worldwide. From 3949 to 2049 cal yrs BP, an increasing yet variable trend in TPC and diversity indices, suggests warm-humid conditions prevailed in the region. During the last 1086 cal yrs, an increasing trend is recorded in the palyno assemblage and diversity parameters suggesting ameliorating climate, matches well with the Mediaeval Climate Anomaly (MCA). Our inferences suggest that the palyno assemblage and diversity parameters are quiet sensitive to warm and humid conditions.

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