Warm northern tropical Indian Ocean strengthened the ocean circulation prior to the last glacial termination

Singh, D. K.; Saraswat, Rajeev; Mohtadi, Mahyar; Kumar, Pankaj

doi:10.1016/j.gloplacha.2021.103733

Cited by 6 publications

(2 citation statements)

References 77 publications

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“…The 87 Sr/ 86 Sr, Ɛ Nd , Rb/Sr, CIA, and Al normalized major and trace elements data display a noticeable temporal variation coinciding with the known climatic intervals, such as the Heinrich events, LGM, Early Deglacial, Younger Dryas, and other various cooling events. An earlier study (Singh et al, 2022), based on the samples of this core GC03, demonstrated ∼4°C temperature variation during glacial-interglacial time scale in the time interval of 9-22 ka. In addition, during the same time interval, the sea level has increased by ∼120 m from the Glacial to the Holocene.…”

Section: Sr-nd Isotopic Compositionmentioning

confidence: 72%

“…This core location is strategically selected to know the sediment provenance and to assess the impact of varying climatic events (cold/arid and warm/wet) on the sediment provenances over the EIO. The chronology of this sediment core was established using Accelerated Mass Spectrometer (AMS) radiocarbon dating of mixed planktonic foraminifera (>350 μm size) collected from 18 depths (Singh, 2019;Singh et al, 2022). This core covers the depositional history of sediments up to ∼38 ka with sedimentation rates varying from 4.4 cm/kyr to 31.2 cm/kyr (average: 16.0 cm/kyr).…”

Section: Study Area Core Details and Chronologymentioning

confidence: 99%

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Strong Climate Control on the Millennial‐Scale Dust Variability and Sediment Provenances in the Equatorial Indian Ocean Inferred From Sr‐Nd Isotopes

Shukla,

Singh,

Singh

et al. 2024

Paleoceanog and Paleoclimatol

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High‐resolution Sr and Nd isotope compositions along with major and trace element abundances have been analyzed in silicate fraction of sediments core, SSD004‐GC03, from the Equatorial Indian Ocean (7.2°N and 77.9°E) at 1,540 m water depth with a depositional history of ∼38 ka to determine source variabilities and their controlling factors. 87Sr/86Sr (0.71978–0.72491), ƐNd (−14.8 to −21.9), and a couple of source diagnostic elements display profound variability over the depositional time scale and point toward major sediment contribution from the Peninsular Gneissic Complex (PGC) and the Deccan Basalts along with aeolian dust flux, their relative proportions being determined by climate variability. The cold/arid periods are characterized by an enhanced proportion of aeolian dust and the Deccan Basalts, whereas the sediment contribution from the PGC is augmented during the warm/humid periods. The sediment provenance variations at the Equatorial Indian Ocean coincide very well with known cold/arid (Heinrich Stadial events: HS 1–4, LGM, Younger Dryas, 8.2 ka, 5.2 ka, and 1.1 ka) and warm/humid (Early Deglacial, Holocene Intensified Monsoon) climatic events reported in the tropical region and sea‐level change which are strongly captured by the Sr‐Nd isotope and elemental composition of sediments. The present investigation underscores the significant role of climate, mainly the aridity, in modulating the dust fluxes and erosion intensity and the strong coupling between Indian monsoon and North Atlantic climatic oscillations and further demonstrates minimal time delay between the production and transport of sediment from source to sink.

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Section: Sr-nd Isotopic Compositionmentioning

confidence: 72%

Section: Study Area Core Details and Chronologymentioning

confidence: 99%

Strong Climate Control on the Millennial‐Scale Dust Variability and Sediment Provenances in the Equatorial Indian Ocean Inferred From Sr‐Nd Isotopes

Shukla,

Singh,

Singh

et al. 2024

Paleoceanog and Paleoclimatol

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Sub‐centennial upper water column structure variability of the tropical Indian Ocean since the Last Glacial Maximum

Rai,

Singh,

Saraswat

et al. 2024

J Quaternary Science

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The upper water column (UWC) is involved in the worldwide distribution of heat and nutrients. However, global warming is expected to alter the UWC structure due to temperature‐ and precipitation‐induced stratification. This impact of global warming is comparatively more pronounced in the Indian Ocean. Therefore, to understand the fate of the UWC structure in the future, it is important to comprehend its past variability in the Indian Ocean. To achieve this, we have reconstructed sub‐centennial scale variations in the UWC structure of the tropical central Indian Ocean by using the isotopic composition (δ18O and δ13C) of surface‐dwelling planktic foraminifera Globigerinoides ruber and subsurface‐dwelling Neogloboquadrina dutertrei. The difference in the isotopic composition of the surface‐ and subsurface‐dwelling species (Δδ18Or‐d and Δδ13Cr‐d) was used to understand the UWC structure variability in the tropical central Indian Ocean. We report a deeper mixed layer and thermocline during the last glacial period, followed by a shoaling of the thermocline during the glacial–interglacial transition. The thermocline also deepened during intense boreal summer monsoon events such as in the Bølling–Allerød and early Holocene. Our findings suggest that the tropical Indian Ocean UWC is influenced primarily by the intensity of the monsoon winds. From the comparison of our record with those of the eastern and western Indian Ocean, it is evident that a similar climatic forcing governed the central and eastern regions during the last glacial–interglacial period.

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Recent advancements in marine micropaleontological and paleoceanographic research from India

Singh,

Naidu

2024

Proc.Indian Natl. Sci. Acad.

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Warm northern tropical Indian Ocean strengthened the ocean circulation prior to the last glacial termination

Cited by 6 publications

References 77 publications

Strong Climate Control on the Millennial‐Scale Dust Variability and Sediment Provenances in the Equatorial Indian Ocean Inferred From Sr‐Nd Isotopes

Strong Climate Control on the Millennial‐Scale Dust Variability and Sediment Provenances in the Equatorial Indian Ocean Inferred From Sr‐Nd Isotopes

Sub‐centennial upper water column structure variability of the tropical Indian Ocean since the Last Glacial Maximum

Recent advancements in marine micropaleontological and paleoceanographic research from India

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