Tropical Climate Instability: The Last Glacial Cycle from a Qinghai-Tibetan Ice Core

Science ◽  
1997 ◽  
Vol 276 (5320) ◽  
pp. 1821-1825 ◽  
Author(s):  
L. G. Thompson
Keyword(s):  
Ice Core ◽  
Tropical Climate ◽  
Glacial Cycle ◽  
Last Glacial ◽  
The Last Glacial

scholarly journals Radar stratigraphy connecting Lake Vostok and Dome C, East Antarctica, constrains the EPICA/DMC ice core time scale

2013 ◽  
Vol 7 (1) ◽  
pp. 321-342 ◽  
Author(s):  
M. G. P. Cavitte ◽  
D. D. Blankenship ◽  
D. A. Young ◽  
M. J. Siegert ◽  
E. Le Meur
Keyword(s):  
Ice Core ◽  
Airborne Radar ◽  
Glacial Cycle ◽  
Glacial Cycles ◽  
Last Glacial ◽  
Lake Vostok ◽  
The Last Glacial Maximum ◽  
Radar Technique ◽  
Ice Core Dating ◽  
The Last Glacial

Abstract. New airborne radar sounding surveys at 60 MHz are used to trace internal layering between the Vostok and EPICA Dome C ice core sites. Eleven layers, spanning two glacial cycles from the last glacial maximum back to the MIS 7c interglacial, are used to correlate the two ice core chronologies. Independent of palaeoclimate signals, radar sounding enables correlation of the timescales, with a radar depth uncertainty equivalent to hundreds of years, which is small relative to the ice core dating uncertainties of thousands of years. Along the radar transects, horizons belonging to the last glacial cycle are impacted by aeolian stratigraphic reworking that increases radar technique uncertainty for this interval. However, older layers are used to propagate the higher resolution Vostok ages to the lower resolution Dome C ice core using the Suwa and Bender (2008) Vostok O2 / N2 chronology to give a recalibration of the Parrenin et al. (2007) EPICA EDC3 timescale between 1597 m and 2216 m depth (126 ka to 247 ka age interval).

scholarly journals Atmospheric gas records from Taylor Glacier, Antarctica, reveal ancient ice with ages spanning the entire last glacial cycle

2017 ◽  
Vol 13 (7) ◽  
pp. 943-958 ◽  
Author(s):  
Daniel Baggenstos ◽  
Thomas K. Bauska ◽  
Jeffrey P. Severinghaus ◽  
James E. Lee ◽  
Hinrich Schaefer ◽  
...  
Keyword(s):  
Large Scale ◽  
Ice Core ◽  
Ice Sheet ◽  
Last Deglaciation ◽  
Glacial Cycle ◽  
Last Glacial ◽  
Climate Reconstructions ◽  
Age Model ◽  
Taylor Glacier ◽  
The Last Glacial

Abstract. Old ice for paleo-environmental studies, traditionally accessed through deep core drilling on domes and ridges on the large ice sheets, can also be retrieved at the surface from ice sheet margins and blue ice areas. The practically unlimited amount of ice available at these sites satisfies a need in the community for studies of trace components requiring large sample volumes. For margin sites to be useful as ancient ice archives, the ice stratigraphy needs to be understood and age models need to be established. We present measurements of trapped gases in ice from Taylor Glacier, Antarctica, to date the ice and assess the completeness of the stratigraphic section. Using δ18O of O2 and methane concentrations, we unambiguously identify ice from the last glacial cycle, covering every climate interval from the early Holocene to the penultimate interglacial. A high-resolution transect reveals the last deglaciation and the Last Glacial Maximum (LGM) in detail. We observe large-scale deformation in the form of folding, but individual stratigraphic layers do not appear to have undergone irregular thinning. Rather, it appears that the entire LGM–deglaciation sequence has been transported from the interior of the ice sheet to the surface of Taylor Glacier relatively undisturbed. We present an age model that builds the foundation for gas studies on Taylor Glacier. A comparison with the Taylor Dome ice core confirms that the section we studied on Taylor Glacier is better suited for paleo-climate reconstructions of the LGM due to higher accumulation rates.

scholarly journals NGRIP CH<sub>4</sub> concentration from 120 to 10 kyr before present and its relation to a δ<sup>15</sup>N temperature reconstruction from the same ice core

2014 ◽  
Vol 10 (2) ◽  
pp. 903-920 ◽  
Author(s):  
M. Baumgartner ◽  
P. Kindler ◽  
O. Eicher ◽  
G. Floch ◽  
A. Schilt ◽  
...  
Keyword(s):  
Ice Core ◽  
High Ratio ◽  
Interglacial Period ◽  
Atmospheric Methane ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Concentration Difference ◽  
Temperature Variations ◽  
Last Glacial ◽  
The Last Glacial

Abstract. During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so-called Dansgaard–Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from the Preboreal Holocene (PB) back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the local Greenland NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core (Kindler et al., 2014). We find the ratio to oscillate between 5 parts per billion (ppb) per °C and 18 ppb °C−1 with the approximate frequency of the precessional cycle. A remarkably high ratio of 25.5 ppb °C−1 is reached during the transition from the Younger Dryas (YD) to the PB. Analysis of the timing of the fast methane and temperature increases reveals significant lags of the methane increases relative to NGRIP temperature for DO events 5, 9, 10, 11, 13, 15, 19, and 20. These events generally have small methane increase rates and we hypothesize that the lag is caused by pronounced northward displacement of the source regions from stadial to interstadial. We further show that the relative interpolar concentration difference (rIPD) of methane is about 4.5% for the stadials between DO events 18 and 20, which is in the same order as in the stadials before and after DO event 2 around the Last Glacial Maximum. The rIPD of methane remains relatively stable throughout the full last glacial, with a tendency for elevated values during interstadial compared to stadial periods.

Controls on the East Asian monsoon during the last glacial cycle, based on comparison between Hulu Cave and polar ice-core records

2009 ◽  
Vol 28 (27-28) ◽  
pp. 3291-3302 ◽  
Author(s):  
E.J. Rohling ◽  
Q.S. Liu ◽  
A.P. Roberts ◽  
J.D. Stanford ◽  
S.O. Rasmussen ◽  
...  
Keyword(s):  
Asian Monsoon ◽  
East Asian Monsoon ◽  
East Asian ◽  
Ice Core ◽  
Glacial Cycle ◽  
Polar Ice ◽  
Last Glacial ◽  
The Last Glacial ◽  
Ice Core Records

scholarly journals Dansgaard–Oeschger-like events of the penultimate climate cycle: the loess point of view

2020 ◽  
Vol 16 (2) ◽  
pp. 713-727 ◽  
Author(s):  
Denis-Didier Rousseau ◽  
Pierre Antoine ◽  
Niklas Boers ◽  
France Lagroix ◽  
Michael Ghil ◽  
...  
Keyword(s):  
Ice Core ◽  
Spatial Coherence ◽  
Point Of View ◽  
Optically Stimulated Luminescence ◽  
Glacial Cycle ◽  
Last Glacial ◽  
Climate Cycle ◽  
Statistical Similarity ◽  
The Last Glacial ◽  
Millennial Scale

Abstract. The global character of the millennial-scale climate variability associated with the Dansgaard–Oeschger (DO) events in Greenland has been well-established for the last glacial cycle. Mainly due to the sparsity of reliable data, however, the spatial coherence of corresponding variability during the penultimate cycle is less clear. New investigations of European loess records from Marine Isotope Stage (MIS) 6 reveal the occurrence of alternating loess intervals and paleosols (incipient soil horizons), similar to those from the last climatic cycle. These paleosols are correlated, based on their stratigraphical position and numbers as well as available optically stimulated luminescence (OSL) dates, with interstadials described in various Northern Hemisphere records and in GLt_syn, the synthetic 800 kyr record of Greenland ice core δ18O. Therefore, referring to the interstadials described in the record of the last climate cycle in European loess sequences, the four MIS 6 interstadials can confidently be interpreted as DO-like events of the penultimate climate cycle. Six more interstadials are identified from proxy measurements performed on the same interval, leading to a total of 10 interstadials with a DO-like event status. The statistical similarity between the millennial-scale loess–paleosol oscillations during the last and penultimate climate cycle provides direct empirical evidence that the cycles of the penultimate cycle are indeed of the same nature as the DO cycles originally discovered for the last glacial cycle. Our results thus imply that their underlying cause and global imprint were characteristic of at least the last two climate cycles.

scholarly journals DO-like events of the penultimate climate cycle: the loess point of view

2019 ◽  
Author(s):  
Denis-Didier Rousseau ◽  
Pierre Antoine ◽  
Niklas Boers ◽  
France Lagroix ◽  
Michael Ghil ◽  
...  
Keyword(s):  
Ice Core ◽  
Spatial Coherence ◽  
Point Of View ◽  
Optically Stimulated Luminescence ◽  
Glacial Cycle ◽  
Last Glacial ◽  
Climate Cycle ◽  
Statistical Similarity ◽  
The Last Glacial ◽  
Millennial Scale

Abstract. The global character of the millennial-scale climate variability associated with the Dansgaard-Oeschger (DO) events in Greenland has been well-established for the last glacial cycle. Mainly due to the sparsity of reliable data, however, the spatial coherence of corresponding variability during the penultimate cycle is less clear. New investigations of European loess records from MIS 6 reveal the occurrence of alternating loess intervals and paleosols (incipient soil horizons), similar to those from the last climatic cycle. These paleosols are correlated based on their stratigraphical position and numbers, and available optically stimulated luminescence (OSL) dates with interstadials described in various Northern Hemisphere records as well as in GLt_syn, the synthetic 800-kyr record of Greenland ice core δ18O. Therefore, referring to the interstadials described in the record of the last climate cycle in European loess sequences, the MIS 6 interstadials can confidently be interpreted as DO-like events of the penultimate climate cycle. The statistical similarity between the millennial-scale loess-paleosol oscillations during the last and penultimate climate cycle provides direct empirical evidence that the cycles of the penultimate cycle are indeed of the same nature as the DO cycles originally discovered for the last glacial cycle. Our results thus imply that their underlying cause and global imprint was characteristic of at least the last two climate cycles.

scholarly journals NGRIP CH<sub>4</sub> concentration from 120 to 10 kyr before present and its relation to a δ<sup>15</sup>N temperature reconstruction from the same ice core

2013 ◽  
Vol 9 (4) ◽  
pp. 4655-4704 ◽  
Author(s):  
M. Baumgartner ◽  
P. Kindler ◽  
O. Eicher ◽  
G. Floch ◽  
A. Schilt ◽  
...  
Keyword(s):  
Ice Core ◽  
High Sensitivity ◽  
Interglacial Period ◽  
Atmospheric Methane ◽  
Glacial Cycle ◽  
Last Interglacial ◽  
Concentration Difference ◽  
Temperature Variations ◽  
Last Glacial ◽  
The Last Glacial

Abstract. During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so called Dansgaard-Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from Termination 1 back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core. We find the sensitivity to oscillate between 5 parts per billion by volume (ppbv) per °C and 18 ppbv °C−1 with the approximate frequency of the precessional cycle. A remarkably high sensitivity of 25.5 ppbv °C−1 is reached during Termination 1. Analysis of the timing of the fast methane and temperature increases reveals significant lags of the methane increases relative to NGRIP temperature for the DO events 5, 9, 10, 11, 13, 15, 19, and 20. We further show that the relative interpolar concentration difference of methane is 4.6 ± 0.7% between the DO events 18 and 19 and 4.4 ± 0.8% between the DO events 19 to 20, which is in the same order as in the stadials before and after DO event 2 around the Last Glacial Maximum.

scholarly journals Atmospheric gas records from Taylor Glacier, Antarctica, reveal ancient ice with ages spanning the entire last glacial cycle

2017 ◽  
Author(s):  
Daniel Baggenstos ◽  
Thomas K. Bauska ◽  
Jeffrey P. Severinghaus ◽  
James E. Lee ◽  
Hinrich Schaefer ◽  
...  
Keyword(s):  
Large Scale ◽  
Ice Core ◽  
Ice Sheet ◽  
Last Deglaciation ◽  
Glacial Cycle ◽  
Last Glacial ◽  
Climate Reconstructions ◽  
Age Model ◽  
Taylor Glacier ◽  
The Last Glacial

Abstract. Old ice for paleo-environmental studies, traditionally accessed through deep core drilling on domes and ridges on the large ice sheets, can also be retrieved at the surface from ice sheet margins and blue ice areas. The practically unlimited amount of ice available at these sites satisfies a need in the community for studies of trace components requiring large sample volumes. For margin sites to be useful as ancient ice archives, the ice stratigraphy needs to be understood and age models need to be established. We present measurements of trapped gases in ice from Taylor Glacier, Antarctica, to date the ice and assess the completeness of the stratigraphic section. Using δ18O of O2 and methane concentrations, we unambiguously identify ice from the last glacial cycle, covering every climate interval from the early Holocene to the penultimate interglacial. A high-resolution transect reveals the last deglaciation and the Last Glacial Maximum (LGM) in detail. We observe large-scale deformation in the form of folding, but individual stratigraphic layers do not appear to have undergone irregular thinning. Rather, it appears that the entire LGM-deglaciation sequence has been transported from the interior of the ice sheet to the surface of Taylor Glacier relatively undisturbed. We present an age model that builds the foundation for gas studies on Taylor Glacier. A comparison with the Taylor Dome ice core confirms that the section we studied on Taylor Glacier is better suited for paleo-climate reconstructions of the LGM due to higher accumulation rates.

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