Multi-proxy analyses of sediment cores from the Pakistan continental margin

Late Holocene laminated sediments from a core transect centred in the oxygen minimum zone (OMZ) impinging at the continental slope off Pakistan indicate stable oxygen minimum conditions for the past 7000 calendar years. High SW-monsoon-controlled biological productivity and enhanced organic matter preservation during this period is reflected in high contents of total organic carbon (TOC) and redox-sensitive elements (Ni, V), as well as by a low-diversity, high-abundance benthic foraminiferal Buliminacea association and high abundance of the planktonic species Globigerina bulloides indicative of upwelling conditions. Surface-water productivity was strongest during SW monsoon maxima. Stable OMZ conditions (reflected by laminated sediments) were found also during warm interstadial events (Preboreal, Bølling-Allerød, and Dansgaard-Oeschger events), as well as during peak glacial times (17-22.5 ka, all ages in calendar years). Sediment mass accumulation rates were at a maximum during the Preboreal and Younger Dryas periods due to strong riverine input and mobilisation of fine-grained sediment coinciding with rapid deglacial sea-level rise, whereas eolian input generally decreased from glacial to interglacial times. In contrast, the occurrence of bioturbated intervals from 7 to 10.5 ka (early Holocene), in the Younger Dryas (11.7-13 ka), from 15 to 17 ka (Heinrich event 1) and from 22.5 to 25 ka (Heinrich event 2) suggests completely different conditions of oxygen-rich bottom waters, extremely low mass and organic carbon accumulation rates, a high-diversity benthic fauna, all indicating lowered surface-water productivity. During these intervals the OMZ was very poorly developed or absent and a sharp fall of the aragonite compensation depth favoured the preservation of pteropods. The abundance of lithogenic proxies suggests aridity and wind transport by northwesterly or northeasterly winds during these periods coinciding with the North Atlantic Heinrich events and dust peaks in the Tibetan Loess records. The correlation of the monsoon-driven OMZ variability in the Arabian Sea with the rapid climatic fluctuations in the high northern latitudes suggests a close coupling between the climates of the high and low latitudes at a global scale.

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von Rad, Ulrich, Schulz, Hartmut, Riech, Volkher, den Dulk, Marieke, Berner, Ulrich, Sirocko, Frank (1999). Dataset: Multi-proxy analyses of sediment cores from the Pakistan continental margin. https://doi.org/10.1594/PANGAEA.735733

DOI retrieved: 1999

Additional Info

Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.735733
Author von Rad, Ulrich
Given Name Ulrich
Family Name von Rad
More Authors
Schulz, Hartmut
Riech, Volkher
den Dulk, Marieke
Berner, Ulrich
Sirocko, Frank
Source Creation 1999
Publication Year 1999
Resource Type application/zip - filename: von-Rad_1999
Subject Areas
Name: LandSurface

Name: Lithosphere

Name: Paleontology

Related Identifiers
Title: Multiple monsoon-controlled breakdown of oxygen-minimum conditions during the past 30,000 years documented in laminated sediment off Pakistan
Identifier: https://doi.org/10.1016/S0031-0182(99)00042-5
Type: DOI
Relation: IsSupplementTo
Year: 1999
Source: Palaeogeography, Palaeoclimatology, Palaeoecology
Authors: von Rad Ulrich , Schulz Hartmut , Riech Volkher , den Dulk Marieke , Berner Ulrich , Sirocko Frank .