The Greenland Ice Sheet Project 2 depth‐age scale: Methods and results

Meese, D. A.; Gow, Anthony J.; Alley, Richard B.; Zielinski, Gregory A.; Grootes, P. M.; Ram, Michael; Taylor, Kendrick C.; Mayewski, Paul Andrew; Bolzan, John F.

doi:10.1029/97jc00269

Cited by 459 publications

(340 citation statements)

References 43 publications

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“…They suggest that the counting error be estimated through either repeated counts by one analyst or several analysts counting the same section in the same manner. This is the method that was applied for the GISP2 stratigraphy Meese et al, 1997). The error may be estimated as the root mean squared error of the different counts, but this estimate is too optimistic because it does not take into account that the counters are not necessarily completely independent, as they may have the same bias.…”

Section: Discussion Of Error Estimatementioning

confidence: 99%

“…It has also been shown that visible stratigraphy and variations in physical properties of the ice can reveal the annual layering Meese et al, 1997;Svensson et al, 2005).…”

Section: Identification Of Annual Layersmentioning

confidence: 99%

“…Greenland ice cores generally have a higher temporal resolution than Antarctic ice cores, and thus have a higher potential for accurate dating. The so far most used stratigraphic ice core chronology for the last glacial period is that of the GISP2 ice core Alley et al, 1997;Meese et al, 1997), based on visual stratigraphy (VS), high resolution Laser Light Scattering measurements, and the conductivity of the solid ice. The most used timescales for the GRIP ice core are the model timescales ss09 (Johnsen and Dansgaard, 1992) and ss09sea (Johnsen et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

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The Greenland Ice Core Chronology 2005, 15–42ka. Part 1: constructing the time scale

Andersen

Svensson

Johnsen

et al. 2006

Quaternary Science Reviews

626

329

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The Greenland Ice Core Chronology 2005, GICC05, is extended back to 42 ka b2k (before 2000 AD), i.e. to the end of Greenland Stadial 11. The chronology is based on independent multi-parameter counting of annual layers using comprehensive high-resolution measurements available from the North Greenland Ice Core Project, NGRIP. These are measurements of visual stratigraphy, conductivity of the solid ice, electrolytical melt water conductivity and the concentration of Na + , Ca 2+ , SO 4 2À , NO 3 À , NH 4 + . An uncertainty estimate of the time scale is obtained from identification of 'uncertain' annual layers, which are counted as 0.570.5 years. The sum of the uncertain annual layers, the so-called maximum counting error of the presented chronology ranges from 4% in the warm interstadial periods to 7% in the cold stadials. The annual accumulation rates of the stadials and interstadials are on average one-third and half of the present day values, respectively, and the onset of the Greenland Interstadials 2, 3, and 8, based on 20 year averaged d 18 O values, are determined as 23,340, 27,780, and 38,220 yr b2k in GICC05. r

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Section: Discussion Of Error Estimatementioning

confidence: 99%

“…It has also been shown that visible stratigraphy and variations in physical properties of the ice can reveal the annual layering Meese et al, 1997;Svensson et al, 2005).…”

Section: Identification Of Annual Layersmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The Greenland Ice Core Chronology 2005, 15–42ka. Part 1: constructing the time scale

Andersen

Svensson

Johnsen

et al. 2006

Quaternary Science Reviews

626

329

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“…The Cape Basin Nd isotope record is displayed using the revised chronology for core TNO75-21 of Kissel et al (2008). To facilitate comparison between the two deep water Nd isotope records, the chronology of Kissel et al (2008) for Cape Basin core TNO75-21, which is based on the GISP2 chronology of Meese et al (1997) has been adjusted to the revised GRIP/GISP2 chronology of Shackleton et al (2004 …”

Section: Discussionmentioning

confidence: 99%

Changes in North Atlantic Deep Water strength and bottom water masses during Marine Isotope Stage 3 (45–35kaBP)

Gutjahr

Hoogakker

McCave

2010

Quaternary Science Reviews

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a b s t r a c tThe strength of the North Atlantic Meridional Overturning Circulation during climatically highly variable Marine Isotope Stage (MIS) 3 has attracted much attention in recent years. Here we present highresolution Nd isotope compositions of past seawater derived from authigenic FeeMn oxyhydroxides recovered from drift sediments on the Blake Ridge in the deep western North Atlantic (ODP Leg 172, Site 1060, 3481 m water depth). The data cover the period from 45 to 35 ka BP, tracing circulation changes during major Heinrich iceberg discharge event 4 (H4, w40e39 ka BP). The Nd isotope record suggests that there was no northern-source water (NSW) mass like modern NADW at the deeper part of Blake Ridge at any time between 45 and 35 ka. This is fundamentally different from the hydrographic situation during the Holocene where NADW extends below 4500 m at this location. The 3 Nd of past deep water recorded in the Blake Ridge sediments was least radiogenic during Dansgaard/Oeschger (D/O) Interstadial (IS) 8 (3 Nd ¼ À11.3) and most radiogenic immediately preceding IS 9 (3 Nd ¼ À9.8). More radiogenic compositions were also recorded during H4 (À10.2 3 Nd À9.9). The Nd isotope variability in MIS 3 matches that of a physical bottom current strength reconstruction from the same location. Neither record follows the pattern of Northern Hemisphere D/O climatic cycles. In our record, reduced mixing with northern source waters started in stadial 12 and lasted until after H4 in stadial 9, followed by a rapid increase in NSW contribution thereafter. This major change in the Nd isotope record predates the iceberg discharge event Heinrich 4 by more than 3 ka indicating a shallowing of the water mass boundary between Glacial North Atlantic Intermediate Water and Southern Source Water beneath. This early change in bottom water properties at the deep Blake Ridge suggests that North Atlantic deep water advection may already have decreased several thousand years before the actual iceberg discharge event and associated freshening of the surface waters in the North Atlantic. The change can thus not be attributed to climatic events in the North Atlantic but may be related to changes in flux of deep water from the South.

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“…GISP2 samples were from 132-138 m depth in the G2 core and are approximately 400-430 years old [Meese et al, 1997]. Vostok samples were from the 110-111 m section of the BH-5 core and from selected depths between 1096 and 1404 m from the 5G deep core.…”

Section: Methodsmentioning

confidence: 99%