A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean
High-resolution sediment records from North Atlantic deep-sea sediments have been used to document millennial-scale abrupt climate oscillations during the last glacial cycle. A five-meter core (DY081-GVY002) was recovered from the Orphan Knoll, Northwest Atlantic Ocean during the RRS Discovery Cruis...
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ftsalemstateuniv:oai:digitalrepository.salemstate.edu:20.500.13013/1512 2023-05-15T17:32:35+02:00 A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean Anastopoulos, Kristen M. Cullen, James L. Cullen, James 2021-11-24T14:05:45.000 https://hdl.handle.net/20.500.13013/1512 unknown researchday/2021/undergradposters/24 http://hdl.handle.net/20.500.13013/1512 Atlantic Detrital Heinrich Event IRD Sediment event 2021 ftsalemstateuniv https://doi.org/20.500.13013/1512 2022-09-22T17:26:32Z High-resolution sediment records from North Atlantic deep-sea sediments have been used to document millennial-scale abrupt climate oscillations during the last glacial cycle. A five-meter core (DY081-GVY002) was recovered from the Orphan Knoll, Northwest Atlantic Ocean during the RRS Discovery Cruise ICY LAB in 2017. Forty-closely spaced samples from the top 65cm (1-2 cm spacing) have been used to generate two proxies that record changes in the input of ice-rafted detritus (IRD): IRD/g, lithic grains >150µm per gram of sediment, %IRD ((number of lithic grains >150µm) / (number of lithic grains >150µm + number of planktic foraminifers >150µm)) x 100). Our record, which significantly improves the resolution previously presented by Gugliemli et al. (2020), reveals a series of abrupt increases in IRD input ranging from 4,000-7,200 lithic grains/g within a background of 3,000 or less lithic grains/g, at 5cm, 10cm, 25cm, 38cm and 44cm. The %IRD record reveals high values over the interval of 34cm-55cm that correspond to high IRD/g input which can be correlated to an interval of high Ca/Sr ratios, a proxy that has been previously used to indicate the input of detrital carbonates composed of dolomite and/or inorganic calcite (Hodell et al. 2008). We have preliminarily correlated this interval to Heinrich event 1 (H1), one of a series of abrupt increases in IRD input that occurred throughout the North Atlantic during the last glacial (MIS 4-2); (Heinrich 1988). Another high interval in the Ca/Sr ratio occurs at 12-15cm this corresponds to a peak in %IRD, we have preliminarily correlated this interval as Heinrich event 0 (H0). Our data suggests a closer relationship between %IRD and Ca/Sr proxies, whereas IRD/g is more easily influenced by other factors. The other peaks in IRD/g that also record low %IRD occur when Ca/Sr ratios are at lower background levels, suggesting the decoupling of these proxies for reasons we have not been able to explain yet. Other/Unknown Material North Atlantic Northwest Atlantic Salem State University: Digital Commons Orphan Knoll ENVELOPE(-46.500,-46.500,50.500,50.500) |
institution |
Open Polar |
collection |
Salem State University: Digital Commons |
op_collection_id |
ftsalemstateuniv |
language |
unknown |
topic |
Atlantic Detrital Heinrich Event IRD Sediment |
spellingShingle |
Atlantic Detrital Heinrich Event IRD Sediment Anastopoulos, Kristen M. Cullen, James L. A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean |
topic_facet |
Atlantic Detrital Heinrich Event IRD Sediment |
description |
High-resolution sediment records from North Atlantic deep-sea sediments have been used to document millennial-scale abrupt climate oscillations during the last glacial cycle. A five-meter core (DY081-GVY002) was recovered from the Orphan Knoll, Northwest Atlantic Ocean during the RRS Discovery Cruise ICY LAB in 2017. Forty-closely spaced samples from the top 65cm (1-2 cm spacing) have been used to generate two proxies that record changes in the input of ice-rafted detritus (IRD): IRD/g, lithic grains >150µm per gram of sediment, %IRD ((number of lithic grains >150µm) / (number of lithic grains >150µm + number of planktic foraminifers >150µm)) x 100). Our record, which significantly improves the resolution previously presented by Gugliemli et al. (2020), reveals a series of abrupt increases in IRD input ranging from 4,000-7,200 lithic grains/g within a background of 3,000 or less lithic grains/g, at 5cm, 10cm, 25cm, 38cm and 44cm. The %IRD record reveals high values over the interval of 34cm-55cm that correspond to high IRD/g input which can be correlated to an interval of high Ca/Sr ratios, a proxy that has been previously used to indicate the input of detrital carbonates composed of dolomite and/or inorganic calcite (Hodell et al. 2008). We have preliminarily correlated this interval to Heinrich event 1 (H1), one of a series of abrupt increases in IRD input that occurred throughout the North Atlantic during the last glacial (MIS 4-2); (Heinrich 1988). Another high interval in the Ca/Sr ratio occurs at 12-15cm this corresponds to a peak in %IRD, we have preliminarily correlated this interval as Heinrich event 0 (H0). Our data suggests a closer relationship between %IRD and Ca/Sr proxies, whereas IRD/g is more easily influenced by other factors. The other peaks in IRD/g that also record low %IRD occur when Ca/Sr ratios are at lower background levels, suggesting the decoupling of these proxies for reasons we have not been able to explain yet. |
author2 |
Cullen, James |
format |
Other/Unknown Material |
author |
Anastopoulos, Kristen M. Cullen, James L. |
author_facet |
Anastopoulos, Kristen M. Cullen, James L. |
author_sort |
Anastopoulos, Kristen M. |
title |
A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean |
title_short |
A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean |
title_full |
A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean |
title_fullStr |
A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean |
title_full_unstemmed |
A Late Glacial to Holocene Sediment Record of Ice-Rafted Detritus from Orphan Knoll, Northwest Atlantic Ocean |
title_sort |
late glacial to holocene sediment record of ice-rafted detritus from orphan knoll, northwest atlantic ocean |
publishDate |
2021 |
url |
https://hdl.handle.net/20.500.13013/1512 |
long_lat |
ENVELOPE(-46.500,-46.500,50.500,50.500) |
geographic |
Orphan Knoll |
geographic_facet |
Orphan Knoll |
genre |
North Atlantic Northwest Atlantic |
genre_facet |
North Atlantic Northwest Atlantic |
op_relation |
researchday/2021/undergradposters/24 http://hdl.handle.net/20.500.13013/1512 |
op_doi |
https://doi.org/20.500.13013/1512 |
_version_ |
1766130769235804160 |