Variations in productivity and eolian fluxes in the northeastern Arabian Sea during the past 110 ka

Ali Pourmand, Franco Marcantonio, Hartmut Schulz

Research output: Contribution to journalArticle

43 Citations (Scopus)

Abstract

High-resolution (one to two samples/ka) radionuclide proxy records from core 93KL in the northeastern Arabian Sea provide evidence for millennial climate variability over the past 110 ka. We interpret 230Th-normalized 232Th fluxes as a proxy for eolian input, and authigenic uranium concentrations as a proxy for past productivity. We attribute orbital and suborbital variations in both proxies to changes in the intensity of the southwest Indian Ocean monsoon. The highest 230Th-normalized 232Th fluxes occur at times that are consistent with the timing of the Younger Dryas, Heinrich events 1-7 and cold Dansgaard-Oeschger stadial events recorded in the GISP2 ice core. Such high dust fluxes may be due to a weakened southwest monsoon in conjunction with strengthened northwesterlies from the Arabian Peninsula and Mesopotamia. Authigenic uranium concentrations, on the other hand, are highest during warm Dansgaard-Oeschger interstadials when the southwest monsoon is intensified relative to the northwesterly winds. Our results also indicate that on orbital timescales maximum average eolian fluxes coincide with the timing of marine isotopic stage (MIS) 2 and 4, while minimum fluxes occur during MIS 1, 3 and 5. Although the forcing mechanism(s) controlling suborbital variabilities in monsoonal intensity is still debated, our findings suggest an atmospheric teleconnection between the low-latitude southwest monsoon and North Atlantic climate.

Original languageEnglish (US)
Pages (from-to)39-54
Number of pages16
JournalEarth and Planetary Science Letters
Volume221
Issue number1-4
DOIs
StatePublished - Apr 30 2004
Externally publishedYes

Fingerprint

Arabian Sea
productivity
monsoons
monsoon
Productivity
Fluxes
Uranium
uranium
climate
Heinrich event
time measurement
interstadial
teleconnection
Younger Dryas
orbitals
ice core
Indian Ocean
Ice
peninsulas
radionuclide

Keywords

  • Eolian flux
  • Indian Ocean monsoon
  • Millennial variations
  • Productivity
  • Uranium-thorium

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

Cite this

Variations in productivity and eolian fluxes in the northeastern Arabian Sea during the past 110 ka. / Pourmand, Ali; Marcantonio, Franco; Schulz, Hartmut.

In: Earth and Planetary Science Letters, Vol. 221, No. 1-4, 30.04.2004, p. 39-54.

Research output: Contribution to journalArticle

@article{a3dd7b07b2cc40928a5262c06973cf8d,
title = "Variations in productivity and eolian fluxes in the northeastern Arabian Sea during the past 110 ka",
abstract = "High-resolution (one to two samples/ka) radionuclide proxy records from core 93KL in the northeastern Arabian Sea provide evidence for millennial climate variability over the past 110 ka. We interpret 230Th-normalized 232Th fluxes as a proxy for eolian input, and authigenic uranium concentrations as a proxy for past productivity. We attribute orbital and suborbital variations in both proxies to changes in the intensity of the southwest Indian Ocean monsoon. The highest 230Th-normalized 232Th fluxes occur at times that are consistent with the timing of the Younger Dryas, Heinrich events 1-7 and cold Dansgaard-Oeschger stadial events recorded in the GISP2 ice core. Such high dust fluxes may be due to a weakened southwest monsoon in conjunction with strengthened northwesterlies from the Arabian Peninsula and Mesopotamia. Authigenic uranium concentrations, on the other hand, are highest during warm Dansgaard-Oeschger interstadials when the southwest monsoon is intensified relative to the northwesterly winds. Our results also indicate that on orbital timescales maximum average eolian fluxes coincide with the timing of marine isotopic stage (MIS) 2 and 4, while minimum fluxes occur during MIS 1, 3 and 5. Although the forcing mechanism(s) controlling suborbital variabilities in monsoonal intensity is still debated, our findings suggest an atmospheric teleconnection between the low-latitude southwest monsoon and North Atlantic climate.",
keywords = "Eolian flux, Indian Ocean monsoon, Millennial variations, Productivity, Uranium-thorium",
author = "Ali Pourmand and Franco Marcantonio and Hartmut Schulz",
year = "2004",
month = "4",
day = "30",
doi = "10.1016/S0012-821X(04)00109-8",
language = "English (US)",
volume = "221",
pages = "39--54",
journal = "Earth and Planetary Sciences Letters",
issn = "0012-821X",
publisher = "Elsevier",
number = "1-4",

}

TY - JOUR

T1 - Variations in productivity and eolian fluxes in the northeastern Arabian Sea during the past 110 ka

AU - Pourmand, Ali

AU - Marcantonio, Franco

AU - Schulz, Hartmut

PY - 2004/4/30

Y1 - 2004/4/30

N2 - High-resolution (one to two samples/ka) radionuclide proxy records from core 93KL in the northeastern Arabian Sea provide evidence for millennial climate variability over the past 110 ka. We interpret 230Th-normalized 232Th fluxes as a proxy for eolian input, and authigenic uranium concentrations as a proxy for past productivity. We attribute orbital and suborbital variations in both proxies to changes in the intensity of the southwest Indian Ocean monsoon. The highest 230Th-normalized 232Th fluxes occur at times that are consistent with the timing of the Younger Dryas, Heinrich events 1-7 and cold Dansgaard-Oeschger stadial events recorded in the GISP2 ice core. Such high dust fluxes may be due to a weakened southwest monsoon in conjunction with strengthened northwesterlies from the Arabian Peninsula and Mesopotamia. Authigenic uranium concentrations, on the other hand, are highest during warm Dansgaard-Oeschger interstadials when the southwest monsoon is intensified relative to the northwesterly winds. Our results also indicate that on orbital timescales maximum average eolian fluxes coincide with the timing of marine isotopic stage (MIS) 2 and 4, while minimum fluxes occur during MIS 1, 3 and 5. Although the forcing mechanism(s) controlling suborbital variabilities in monsoonal intensity is still debated, our findings suggest an atmospheric teleconnection between the low-latitude southwest monsoon and North Atlantic climate.

AB - High-resolution (one to two samples/ka) radionuclide proxy records from core 93KL in the northeastern Arabian Sea provide evidence for millennial climate variability over the past 110 ka. We interpret 230Th-normalized 232Th fluxes as a proxy for eolian input, and authigenic uranium concentrations as a proxy for past productivity. We attribute orbital and suborbital variations in both proxies to changes in the intensity of the southwest Indian Ocean monsoon. The highest 230Th-normalized 232Th fluxes occur at times that are consistent with the timing of the Younger Dryas, Heinrich events 1-7 and cold Dansgaard-Oeschger stadial events recorded in the GISP2 ice core. Such high dust fluxes may be due to a weakened southwest monsoon in conjunction with strengthened northwesterlies from the Arabian Peninsula and Mesopotamia. Authigenic uranium concentrations, on the other hand, are highest during warm Dansgaard-Oeschger interstadials when the southwest monsoon is intensified relative to the northwesterly winds. Our results also indicate that on orbital timescales maximum average eolian fluxes coincide with the timing of marine isotopic stage (MIS) 2 and 4, while minimum fluxes occur during MIS 1, 3 and 5. Although the forcing mechanism(s) controlling suborbital variabilities in monsoonal intensity is still debated, our findings suggest an atmospheric teleconnection between the low-latitude southwest monsoon and North Atlantic climate.

KW - Eolian flux

KW - Indian Ocean monsoon

KW - Millennial variations

KW - Productivity

KW - Uranium-thorium

UR - http://www.scopus.com/inward/record.url?scp=2342435149&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=2342435149&partnerID=8YFLogxK

U2 - 10.1016/S0012-821X(04)00109-8

DO - 10.1016/S0012-821X(04)00109-8

M3 - Article

VL - 221

SP - 39

EP - 54

JO - Earth and Planetary Sciences Letters

JF - Earth and Planetary Sciences Letters

SN - 0012-821X

IS - 1-4

ER -