TALDICE-1 age scale of the Talos Dome deep ice core, East Antarctica

Buiron, D.; Chappellaz, J.; Stenni, Barbara; Frezzotti, Màssimo; Baumgartner, Michael F.; Capron, Émilie; Landais, A.; Lemieux‐Dudon, Bénédicte; Masson‐Delmotte, Valérie; Montagnat, Mâurine; Parrenin, Frédéric; Schilt, A.

doi:10.5194/cpd-6-1733-2010

Cited by 11 publications

(9 citation statements)

References 74 publications

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“…However, although it is predicted that the accumulation rate at EDML was reduced with respect to Talos Dome during this period, this reduction is assumed to be at most 25% (0.033 versus 0.045 m water equivalent yr −1 at EDML and Talos Dome, respectively) [ Veres et al , ]. Moreover, such an anomalous dampening would be expected in other gas records as well, but as shown in Figure , dampening of the [CH 4 ] signal is not observed [ Schilt et al , ; Buiron et al , ; Stenni et al , ].…”

Section: Methods and Data Qualitymentioning

confidence: 95%

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

et al. 2016

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We present new 13 C measurements of atmospheric CO 2 covering the last glacial/interglacial cycle, complementing previous records covering Terminations I and II. Most prominent in the new record is a significant depletion in 13 C(atm) of 0.5‰ occurring during marine isotope stage (MIS) 4, followed by an enrichment of the same magnitude at the beginning of MIS 3. Such a significant excursion in the record is otherwise only observed at glacial terminations, suggesting that similar processes were at play, such as changing sea surface temperatures, changes in marine biological export in the Southern Ocean (SO) due to variations in aeolian iron fluxes, changes in the Atlantic meridional overturning circulation, upwelling of deep water in the SO, and long-term trends in terrestrial carbon storage. Based on previous modeling studies, we propose constraints on some of these processes during specific time intervals. The decrease in 13 C(atm) at the end of MIS 4 starting approximately 64 kyr B.P. was accompanied by increasing [CO 2 ]. This period is also marked by a decrease in aeolian iron flux to the SO, followed by an increase in SO upwelling during Heinrich event 6, indicating that it is likely that a large amount of 13 C-depleted carbon was transferred to the deep oceans previously, i.e., at the onset of MIS 4. Apart from the upwelling event at the end of MIS 4 (and potentially smaller events during Heinrich events in MIS 3), upwelling of deep water in the SO remained reduced until the last glacial termination, whereupon a second pulse of isotopically light carbon was released into the atmosphere.

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Section: Methods and Data Qualitymentioning

confidence: 95%

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

et al. 2016

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“…2) (6); (ii) these peaks of CDM 12, 14, and 17 lag the onset of the corresponding DO event by nearly 1 kyr (Fig. 2); (iii) CO 2 varies also during phases of smaller AIM events (9)(10)(11) (Fig. 1, Inset).…”

Section: Resultsmentioning

confidence: 99%

Mode change of millennial CO ₂ variability during the last glacial cycle associated with a bipolar marine carbon seesaw

Bereiter

Lüthi

Siegrist

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

151

188

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Important elements of natural climate variations during the last ice age are abrupt temperature increases over Greenland and related warming and cooling periods over Antarctica. Records from Antarctic ice cores have shown that the global carbon cycle also plays a role in these changes. The available data shows that atmospheric CO 2 follows closely temperatures reconstructed from Antarctic ice cores during these variations. Here, we present new high-resolution CO 2 data from Antarctic ice cores, which cover the period between 115,000 and 38,000 y before present. Our measurements show that also smaller Antarctic warming events have an imprint in CO 2 concentrations. Moreover, they indicate that during Marine Isotope Stage (MIS) 5, the peak of millennial CO 2 variations lags the onset of Dansgaard/Oeschger warmings by 250 AE 190 y. During MIS 3, this lag increases significantly to 870 AE 90 y. Considerations of the ocean circulation suggest that the millennial variability associated with the Atlantic Meridional Overturning Circulation (AMOC) undergoes a mode change from MIS 5 to MIS 4 and 3. Ocean carbon inventory estimates imply that during MIS 3 additional carbon is derived from an extended mass of carbon-enriched Antarctic Bottom Water. The absence of such a carbon-enriched water mass in the North Atlantic during MIS 5 can explain the smaller amount of carbon released to the atmosphere after the Antarctic temperature maximum and, hence, the shorter lag. Our new data provides further constraints for transient coupled carbon cycleclimate simulations during the entire last glacial cycle.abrupt climate change | CO2-temperature phasing | ice age variability | paleoclimate | greenhouse gas T he climate of the last glacial period is characterized by low global mean temperatures and a number of interhemispheric variations on time scales of several millennia. In the northern hemisphere, in particular on the Greenland ice sheet, large and very rapid temperature jumps of up to 15°C within a few decades, followed by more steady decreases of temperature, have been identified from ice core analyses (1, 2). 25 of these so-called Dansgaard-Oeschger (DO) events have been found during the last glacial period. For each of these events, an associated Antarctic temperature variation has been also documented in Antarctic ice cores (Antarctic Isotope Maximum [AIM] events) (3). Antarctic temperatures increase siteadily when Greenland is in the cold phase and slowly decrease following the abrupt temperature increase in Greenland during a DO event. This behavior is explained by the concept of an oceanic thermal bipolar seesaw, where variations in the Atlantic Meridional Overturning Circulation (AMOC) and associated changes in heat transport across the equator to the North Atlantic modulate the southern and northern hemisphere temperatures during each of these events (4).Previous reconstructions of atmospheric CO 2 concentrations during these millennial-scale variations show that CO 2 varies largely in parallel with the major AIM events (...

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“…Such a depth‐varying fabric (Figure 1c) implies corresponding depth‐varying rheological behavior. Determining this depth‐varying rheological structure is critical for modeling flow near ice divides and interpreting ice core records [ Pettit et al , 2007; Martín et al , 2009; Buiron et al , 2011; Pettit et al , 2011].…”

Section: Introductionmentioning

confidence: 99%

The crystal fabric of ice from full‐waveform borehole sonic logging

Gusmeroli¹,

Pettit²,

Kennedy³

et al. 2012

J. Geophys. Res.

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[1] In an ice sheet, a preferred crystal orientation fabric affects deformation rates because ice crystals are strongly anisotropic: shear along the basal plane is significantly easier than shear perpendicular to the basal plane. The effect of fabric can be as important as temperature in defining deformation rates. Fabric is typically measured using analysis of thin sections under the microscope with co-polarized light. Due to the time-consuming and destructive nature of these measurements, however, it is difficult to capture the spatial variation in fabric necessary for evincing ice sheet flow patterns. Because an ice crystal is similarly elastically anisotropic, the speed of elastic waves through ice can be used as a proxy for quantify anisotropy. We use borehole sonic logging measurements and thin section data from Dome C, East Antarctica to define the relations between apparent fabric and borehole measured elastic speeds (compressional V P and vertically polarized shear V SV ). These relations, valid for single maximum fabrics, allow in-situ, depth-continuous fabric estimates of unimodal fabric strength from borehole sonic logging. We describe the single maximum fabric using a 1 : the largest eigenvalue of the second-order orientation tensor. For ice at À16C and a 1 in the 0.7-1 range the relations are V P = 248 a 1 3.7 + 3755 m s À1 and V SV = À210a

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TALDICE-1 age scale of the Talos Dome deep ice core, East Antarctica

Cited by 11 publications

References 74 publications

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

Mode change of millennial CO ₂ variability during the last glacial cycle associated with a bipolar marine carbon seesaw

The crystal fabric of ice from full‐waveform borehole sonic logging

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TALDICE-1 age scale of the Talos Dome deep ice core, East Antarctica

Cited by 11 publications

References 74 publications

Evolution of the stable carbon isotope composition of atmospheric CO2 over the last glacial cycle

Evolution of the stable carbon isotope composition of atmospheric CO2 over the last glacial cycle

Mode change of millennial CO 2 variability during the last glacial cycle associated with a bipolar marine carbon seesaw

The crystal fabric of ice from full‐waveform borehole sonic logging

Contact Info

Product

Resources

About

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

Evolution of the stable carbon isotope composition of atmospheric CO₂ over the last glacial cycle

Mode change of millennial CO ₂ variability during the last glacial cycle associated with a bipolar marine carbon seesaw