1. thanks Isla S. Castañeda
Julie Brigham-Grette, Martin Melles, Pavel S. Minyuk,
And the Lake E Science Team
thanks Isla S. Castañeda
Univ Massachusetts, Amherst, MA, United States.
Dept of Geology, University of Cologne, Cologne, Germany.
RAS - NEISRI, Magadan, Russian Federation.
GFZ & Alfred Wegner Institute, Potsdam, Germany.
University of Berlin, Germany.

2. Lake El’gygytgyn (Lake E)
Meteorite
Impact Lake
created
3.58+/ Ma
(Layer, 2000)
Geophysics
Gebhardt et al, 2014;
mass movement deposits
Sauerbray et al,
2014

3. How do they do it!

4. Lake El’gygytgyn
Most continuous record in terrestrial Arctic!

5. Paleomagnetic Reversal Stratigraphy
Composite
Record
5011-1a
5011-1b
Melles et al. 2013; details in
Nowacyzk et al, 2014
Haitia and Nowacyzk, 2014

6. Tuning the record…
See Nowacyzk et al Climate of the Past

8. Sediment Facies super interglacial interglacial Pliocene only never in
the
Pliocene
First
appears
2.6 Ma
MIS 104

9. A different Arctic before 3.0 Ma!
never in
the
Pliocene
▪ No Hudson’s Bay
Ron Blakey paleogeography
Brigham-Grette et al. 2013

10. NHG: stepwise & complex transition
▪ Lake E record: transition from forested arctic to tundra was complex.
▪ Tundra conditions after
~2.3 Ma (like today).
Includes hemlock, fir, pine hapoxylon & larch; walnut
Details in Andreev et al. 2014, Clim. Past
Brigham-Grette et al. 2013

12. Onset of N Hemisphere Glaciation
never in
the
Pliocene
Sea level: Miller et al. 2012
▪ SL change only 20-25m until ~2.5Ma; then 60-70m after N Pacific stratification (LGM ~125m)
▪ first intervals colder than early Holocene only after ~ 2.5 Ma (pCO2 estimated range ppm)
▪ Why do we see persistent forest & elevated temp? What implications does this have for the onset of NHG?

13. Plio-Pleistocene clim. veg. simulations
▪ Lack of temperate forest at 400ppm: under-sensitivity of model to CO2 forcing or possibility that Pliocene GHG levels were higher than proxy reconstructions.
DeConto & Koenig in Brigham-Grette et al. 2013

14. Links between Lake E & Antarctica
▪ ANDRILL diatomaceous ooze (yellow) suggests the absence of a WAIS
▪ The first cold snap at 3.3 Ma (the M2 event) occurs at the same time the WAIS advances into the Ross Sea after being absent for more than 1.2 Myrs.
At Lake E summer temp remained at levels = to the Early Holocene; were not glacial in character. M2
Yellow = no ice
Green = ice expansion
Brigham-Grette et al. 2013

15. 17 Superglacials @ Lake E since 3.2 Ma
Melles, Brigham-Grette, Minyuk et al, 2012
Best match
▪ It is likely that most of the super interglacials at Lake E occur when WAIS retreats.
▪ Best match in MIS 31: orbitally forced warming in Antarctica was followed by extreme warmth in the Arctic half a precession cycle later.

16. Scientific results Potential reason/s?
Krissek et al.
(2007)
Pollard & DeConto (2009)
ANDRILL

17. Super interglacial strength important to GIS
Greenland Ice Sheet likely a bit smaller during MIS 5e (2-3 m of sea level); perhaps it was even smaller during MIS 11 and 31?
MIS 1
5.5 11 31
July
Temp
Mean
Annual
Precip
Melles, Brigham-Grette, Minyuk et al Science 2012

18. Other evidence GIS collapsed MIS 11
Reyes et al, 2014 (June 26, Nature)
…“GIS lost about 4.5 to 6 metres of sea-level-equivalent volume during MIS 11; evidence for GIS collapse after it crossed a climate/ice-sheet stability threshold that may have been no more than
several degrees above pre-industrial temperatures”

20. Mechanism for super interglacials?
Deep
Western
Boundary
Current
11.3 31
882
reduced deep-water intrusion into the Pacific
Hall et al. (2001) Nature
Sen Gupta and England (2004)

22. Mechanism for super interglacials?
▪ Modeling effort: tried to force more warm Pacific water through the Bering straits during a super interglacial.
▪ Result: Lake E did not warm up even if flow increased to 5 Sv (today N flow is 1 Sv)
Evidence that MIS 11 and 31 in the western Arctic was very warm (Cronin et al. 2013).
ca. 50 m deep
ca. 0.8 Sv (106 m3 s-1) into Arctic Ocean
5-6 * 1020 J/yr in 2007
NASA
Bering Strait
e.g., Cronin et al. (2013)
HLY
Sea level
WAIS = 5 m
GIS = 7 m
Enhanced warm-water intrusion into the western Arctic Ocean (?)

23. 400 ppm Start with GIS No retreat. 400 ppm Start with GIS Plus PRISM
Koenig and DeConto, in prep.
400 ppm
Start with GIS
Plus PRISM
SST & sea ice
Top right: Established ice sheet driven by GCM with 400 ppm CO2 (like Pliocene). No retreat.
Bottom right: Ice sheet retreat driven by GCM with 400 ppm CO2 plus PRISM SSTs and Sea Ice. Warm nordic seas and no sea ice makes all the difference- important implications for future sea ice effect on Greenland!
Bot left is the PRISM SST anomaly relative to present day.
Koenig and DeConto, in prep.