首页|Climatic control on the C-3 and C-4 plant abundance during the late Pleistocene-Holocene in the northern Gangetic Plain, India

Climatic control on the C-3 and C-4 plant abundance during the late Pleistocene-Holocene in the northern Gangetic Plain, India

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  • NSTL
  • Elsevier
We synthesise records of stable carbon isotopes (delta C-13 values), TOC/TN, magnetic susceptibility (xlf), palynology, and phytoliths for a late Quaternary lacustrine archive from the northern Gangetic Plain, India to determine the primary driver(s) of past C-3/C-4 plant variability. The study reveals nine climate-driven shifts in vegetation over the last 15.2 ka and provides a comprehensive picture of the evolution of the lake sequence. During 15.2-14.5 ka, lower delta C-13 values, relatively higher TOC/TN ratios and xlf values suggest increasing contribution of C(3 )plant-derived organic matter into the lake and enhanced hydroclimatic conditions in the northern Gangetic Plain. Subsequently, a warm and humid phase corresponding to the B phi lling-Aller phi d interstadial is inferred during 14.5-12.8 ka, followed by evidence of a waning of the Indian Summer Monsoon (ISM) during the Younger Dryas from 12.8-11.7 ka. Despite a strong ISM regime during the early-Greenlandian (11.7-11.0 ka), vegetation shifted from a mixed C-3 -C-4 to a C-4 dominated composition as inferred from higher delta C-13 values, TOC/TN ratios and xlf values. However, a weakened ISM phase is noted between 11.0 and 10.2 ka. On return of warm and humid climatic conditions during 10.2-8.3 ka, tall C-4 Panicoideae grasses flourished around the lake. Two weaker hydroclimatic phases between 8.3 and 6.5 ka and 4.2-2.5 ka favoured C-4-short Chloridoideae grasses over C-4-tall Panicoideae members. Moderate hydroclimatic conditions after 0.6 ka favoured C-4-tall moist-loving grasses. This study shows that before shifting to a C-4-dominated vegetation during the early-Greenlandian to early-Northgrippian, C-3 plants used to dominate the northern Gangetic Plain throughout the late-Pleistocene period. We infer that temperature and rainfall jointly influenced the diversity and distribution of C-4 plants in the northern Gangetic Plain.

Indian summer monsoonGangetic PlainC3C4 vegetationStable carbon isotopePalynologyFRESH-WATER SPONGESCENTRAL GANGA PLAINCORE MONSOON ZONESUMMER MONSOONCENTRAL HIMALAYAORGANIC-MATTERPRECIPITATION VARIABILITYPHYTOLITH ASSEMBLAGESENVIRONMENTAL-CHANGESGRASS SUBFAMILIES

Kumar, Mohan、Saikia, Korobi、Agrawal, Shailesh、Ghosh, Ruby、Ali, Sheikh Nawaz、Arif, Md、Sen Singh, Dhruv、Sharma, Anupam、Phartiyal, Binita、Bajpai, Sunil

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Birbal Sahni Inst Palaeosci

Univ Lucknow

Indian Inst Technol

2022

10.1016/j.palaeo.2022.110890

Palaeogeography, Palaeoclimatology, Palaeoecology

Palaeogeography, Palaeoclimatology, Palaeoecology

ISSN：0031-0182
年,卷(期)：2022.591
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