Econ. Environ. Geol. 2001; 34(2): 217-226

Published online April 30, 2001

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Late Quaternary Deposition of Ice-Rafted Detritus in the Mid-Latitude North Atlantic: Paleoceanographic Evidence on Climatic Instability over the Past 150 Kyr

Myong-Ho Park1* and Byong-Jae Ryu2

1Geologisch-Pal?ontologisches Institut, Universit?t W?rzburg, D-97070 W?rzburg, Germany
2Petroleum ~ Marine Resources Research Division, Korea Institute of Geoscience and Mineral Resources, Taejon 305-350, Korea

Correspondence to :

Myong-Ho Park

mpark0213@hanmail.net

Received: January 19, 2001; Accepted: March 30, 2001

Abstract

Stable isotope, paleoceanographic and sedimentological analyses were carried out along the core M15612 from the Mid-Atlantic Ridge. Distinct negative δ18O anomalies punctuate the planktonic isotope records and correlate with the Heinrich-IRD events. The IRD layer in the core contains varying amounts of quartz, K-feldspar, plagioclase, calcite, dolomite and mica, in which detrital carbonate contributes between 1 and 13% (except H3 and H6). Anomalies are strongest in the N. pachyderma (sin.) isotope record. Systematic changes in the δ18O offset of G. bulloides and G. inflata signify variations in mid-latitude thermocline structure. In conjunction with negative benthic
δ13C anomalies, the data document a stronger contribution of a δ18O depleted, nutrient-rich water mass during the IRD events. The δ13C amplitude of >1‰ between 25 and 57 ka indicates changes between northern source (NADW) and southern source (AABW) water masses at this site. The IRD layers in the core M15612 are correlative with those from the core SO75-26KL and DSDP 609. The IRD layers from the Portuguese margin are coeval with H1, H2 and H4 of the open North Atlantic. This similarity and/or synchronicity in both regions may have been resulted from common changes in a North Atlantic thermohaline switch.

Keywords Heinrich event, IRD layer, stable isotope, detrital carbonate, North Atlantic

Article

Econ. Environ. Geol. 2001; 34(2): 217-226

Published online April 30, 2001

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Late Quaternary Deposition of Ice-Rafted Detritus in the Mid-Latitude North Atlantic: Paleoceanographic Evidence on Climatic Instability over the Past 150 Kyr

Myong-Ho Park1* and Byong-Jae Ryu2

1Geologisch-Pal?ontologisches Institut, Universit?t W?rzburg, D-97070 W?rzburg, Germany
2Petroleum ~ Marine Resources Research Division, Korea Institute of Geoscience and Mineral Resources, Taejon 305-350, Korea

Correspondence to:

Myong-Ho Park

mpark0213@hanmail.net

Received: January 19, 2001; Accepted: March 30, 2001

Abstract

Stable isotope, paleoceanographic and sedimentological analyses were carried out along the core M15612 from the Mid-Atlantic Ridge. Distinct negative δ18O anomalies punctuate the planktonic isotope records and correlate with the Heinrich-IRD events. The IRD layer in the core contains varying amounts of quartz, K-feldspar, plagioclase, calcite, dolomite and mica, in which detrital carbonate contributes between 1 and 13% (except H3 and H6). Anomalies are strongest in the N. pachyderma (sin.) isotope record. Systematic changes in the δ18O offset of G. bulloides and G. inflata signify variations in mid-latitude thermocline structure. In conjunction with negative benthic
δ13C anomalies, the data document a stronger contribution of a δ18O depleted, nutrient-rich water mass during the IRD events. The δ13C amplitude of >1‰ between 25 and 57 ka indicates changes between northern source (NADW) and southern source (AABW) water masses at this site. The IRD layers in the core M15612 are correlative with those from the core SO75-26KL and DSDP 609. The IRD layers from the Portuguese margin are coeval with H1, H2 and H4 of the open North Atlantic. This similarity and/or synchronicity in both regions may have been resulted from common changes in a North Atlantic thermohaline switch.

Keywords Heinrich event, IRD layer, stable isotope, detrital carbonate, North Atlantic

    KSEEG
    Apr 30, 2024 Vol.57 No.2, pp. 107~280

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