Provenance of coarse ice-rafted detritus near the SE Greenland margin

Linthout, K.; Troelstra, S.R.; Kuijpers, A.

doi:10.1017/s0016774600021612

Cited by 11 publications

(8 citation statements)

References 31 publications

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“…The LGM high susceptibility zone extends well beyond these linear trajectories of bottom water transport. The higher susceptibility values are similar to those obtained for potential source samples of igneous (e.g., Icelandic basalt and north Bylot Island granite) rocks (Figure 3), and given their extremely wide spatial distribution across the floor of the North Atlantic Ocean, most likely reflect input of IRD from these and/or similar igneous provinces [e.g., Linthout et al , 2000]. A geographic subset of our LGM samples (the starred points in Figure 3) were sieved and all found to contain rock particles >150 μ m, i.e., particles unambiguously of IRD origin (see ).…”

Section: Resultssupporting

confidence: 77%

Ocean circulation at the Last Glacial Maximum: A combined modeling and magnetic proxy‐based study

2007

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Formation of North Atlantic Deep Water (NADW) is an important component of the ocean thermohaline circulation, but debate exists over the ocean circulation state during glacial stages. Some geological and modeling studies suggest decreased NADW and increased formation of Southern Ocean deep water during the Last Glacial Maximum (LGM); others indicate similar, or higher, rates of NADW advection. Here we test three different potential LGM ocean states by comparing the modeled iceberg trajectories each produces with magnetically mapped patterns and sources of LGM ice‐rafted debris (IRD). The three LGM states are characterized by vigorous NADW formation; deepwater production in the Southern Ocean; and a third, “intermediate” state, with Southern Ocean deepwater formation but also some North Atlantic intermediate water formation. Cluster analysis of sediment magnetic properties was used to characterize North Atlantic IRD patterns and sources, which match most closely iceberg trajectories arising from some combination of the “southern sinking” and “intermediate” ocean circulation states. The magnetic data indicate two major IRD sources, Fennoscandia and Greenland/Iceland, and one minor source, the St. Lawrence region. The model and magnetic data suggest that the LGM North Atlantic circulation was dominated by a cyclonic central North Atlantic gyre, separated from the North Atlantic Current, which was displaced south of ∼42°N.

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Section: Resultssupporting

confidence: 77%

Ocean circulation at the Last Glacial Maximum: A combined modeling and magnetic proxy‐based study

2007

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“…Compositions of the site 918 ice-rafted material re ect a derivation from southeast to central east Greenland. The IRD composition is consistent with the lithologies of larger dropstones recorded during shipboard core description (Shipboard Scienti c Party 1994a), with onshore geology of southeast and central east Greenland (Bridgwater et al 1976;Larsen 1980), and with the composition of modern and Pleistocene IRD from east Greenland (Molnia 1983;Linthout et al 2000).…”

Section: General Ird Provenancesupporting

confidence: 76%

The late Miocene to Pleistocene ice‐rafting history of southeast Greenland

John¹,

Krissek²

2002

Boreas

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Analysis of a Miocene‐Pleistocene ice‐rafted debris (IRD) record from the western Irminger Basin provides evidence for the initiation and long‐term behavior of the SE portion of the Greenland Ice Sheet. In the late Miocene (˜7.3 Ma), IRD supply to Ocean Drilling Program site 918 increased significantly indicating that glaciers large enough to reach sea level were present in SE Greenland long before the onset of widespread Northern Hemisphere glaciation. IRD accumulated at this site throughout the Pliocene and Pleistocene, supporting the hypothesis that SE Greenland was a key nucleation area for the formation of the Greenland Ice Sheet. Since glacial onset, the western Irminger Basin IRD record is characterized by a succession of episodes with high IRD mass accumulation rates (MARs). The site 918 IRD record indicates that greatest iceberg production in SE Greenland occurred during major climatic transitions (e.g. widespread Northern Hemisphere glacial expansion at 2.7 Ma and the mid‐Pleistocene climate shift at 0.9 Ma), and that SE Greenland sometimes also led the northern North Atlantic region in glacial response to climatic forcing (e.g. glacial intensification at ˜4.8 and, along with NE Greenland, at ˜3.5 Ma).

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“…1B). It must be noted here that present-day East Greenland iceberg production is largely concentrated in the Scoresbysund area, immediately northwest of Iceland (Reeh et al, 1999;Linthout et al, 2000). Moreover, present-day advances of polar water masses to northern and northwestern Iceland preferably occur with northwestern to northern wind directions (Ó lafsson, 1999).…”

Section: Petrologic Indicatorsmentioning

confidence: 82%

“…The Blosseville Kyst basalt province in East Greenland (Saunders et al, 1997;Fig. 1A) is situated just northwest of Djú páll and is known for producing icebergs with a sediment load composed of basaltic rock and fragments of plagioclase (Linthout et al, 2000). The basalt/plagioclase ratio (in very fine sand fraction) of Blosseville Kyst derived IRD would most likely be relatively high, with an IRD composition comparable to that of relatively immature basaltic sand near the coast of Iceland, where the ratio is around 5 (Thors, 1974) in comparison with 1-2 at our site (Fig.…”

Section: Petrologic Indicatorsmentioning

confidence: 99%