Stepped Plio-Pleistocene climate variability at Lake El’gygytgyn, NE Arctic Russia, NE BeringiaJulie Brigham-Grette, Martin Melles, Pavel S.

Minyuk,And the Lake E Science Team

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.

thanks Isla S. Castañeda

Lake El’gygytgyn (Lake E)

MeteoriteImpact Lake

created3.58+/- 0.04 Ma

(Layer, 2000)

GeophysicsGebhardt et al, 2014;

mass movement depositsSauerbray et al,

2014

How do they do it!

Lake El’gygytgyn

Most continuous record in terrestrial Arctic!

Paleomagnetic Reversal StratigraphyComposite Record

Haitia and Nowacyzk, 2014

5011-1a 5011-1b

Melles et al. 2013; details inNowacyzk et al, 2014

Tuning the record…

See Nowacyzk et al. 2013 Climate of the Past

Late Cenozoic Arctic History

Questions:▪ Is the Arctic terrestrial history similar to the global marine record?▪ Are their links to Antarctic climate history?

Higher CO2

Some transition

Lower CO2

Sediment Facies

glacial interglacialsuper

interglacial Pliocene only

neverin

the Pliocene

Firstappears2.6 Ma

MIS 104

▪ Facies related to climate modes.

▪ Facies ABC: only in the Pleistocene)

▪ Facies D and E occur only in the Pliocene portion of the record

▪ The first evidence of glacial facies is at 2.6 Ma when the lake first experienced perennial ice cover.

A different Arctic before 3.0 Ma!

neverin

the Pliocene

Firstappears2.6 Ma

MIS 104

Ron Blakey paleogeographyBrigham-Grette et al. 2013

▪ Likely forested conditions to the Arctic borderlands; change in paleogeography = increased continentality.

▪ Deeping of the Hudson Bay and interisland channels likely occurred after the first major glaciations of N America.

▪ No Hudson’s Bay

NHG: stepwise & complex transition

Brigham-Grette et al. 2013

Includes hemlock, fir, pine hapoxylon & larch; walnut

Details in Andreev et al. 2014, Clim. Past

▪ Lake E record: transition from forested arctic to tundra was complex.

▪ Tundra conditions after ~2.3 Ma (like today).

A warm & wet Pliocene

2.2 Ma 3.6 Ma

▪ First major transition: Major drop in precip @ 2.73 Ma ▪ Coincident w change in N Pacific ventilation (onset of stratification)▪ Warm summers & high precipitation become uncoupled after 2.73 ma except during super interglacials

July Temp

Annual Precip

Higher by 4-5o C

3-4x greater

2.73 Ma

neverin

the Pliocene

▪ 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 340-400 ppm)▪ Why do we see persistent forest & elevated temp? What implications does this have for the onset of NHG?

Sea level: Miller et al. 2012

Onset of N Hemisphere Glaciation

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

Links between Lake E & Antarctica

Brigham-Grette et al. 2013

M2

▪ 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.

Yellow = no iceGreen = ice expansion

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.

Scientific resultsPotential reason/s

Pollard & DeConto (2009)

ANDRILL

? ? ?

Krissek et al. (2007)

Super interglacial strength important to GIS

1

Melles, Brigham-Grette, Minyuk et al Science 2012

July Temp

MeanAnnualPrecip

5.5

11

31

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

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 thanseveral degrees above pre-industrial temperatures”

31 49 55 77 879193 105

Mechanism for super interglacials?

Tropical SST (Herbert)

N Atlantic SST (Lawrence)

Lake E wet proxy (Wei)

Lake E productivity

LR04 18O stack

Super interglacials

Super interglacials occur at times when N Atlantic and tropical SSTs are also warm but not necessarily extreme; must be another explanation…

Mechanism for super interglacials?

Deep Western Boundary Current

Hall et al. (2001) Nature Sen Gupta and England (2004)

11.3 31

→ reduced deep-water intrusion into the Pacific

http://www.cmar.csiro.au/currents/jpegs/aust_3oceans.jpg

882

Mechanism for super interglacials?

Decrease in sea ice & ice shelves in Antarctica

Decrease AABW flow northward into Pacific

Decrease Antarctic Bottom water Production

Leads to less upwelling in N Pacific & decreased productivity (BSi)

Evidence: during MIS 11 & 31: extreme drop in sortable silt fraction % in core off NZ coast that is directly below northward flow of AABW (Hall et al., 2001 Nature)

Suggested by Melles et al. 2012

Stratified water column resulted in higher SST in N Pacific – potential to raise air temp and precip over adjacent air masses via effects on dominant pressure patterns (Siberian High & Aleutian Low)

Mechanism for super interglacials?

- 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

Sea level

- WAIS = 5 m- GIS = 7 m

→ Enhanced warm-water intrusioninto the western Arctic Ocean (?)

e.g., Cronin et al. (2013)

HLY0503-06

▪ 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).

Koenig and DeConto, in prep.

Koenig and DeConto, in prep.

400 ppmStart with GISNo retreat.

400 ppmStart with GISPlus PRISM SST & sea ice

▪ First high resolution 3.6 Ma paleoclimate record for the Arctic.

▪ Super interglacials occurred – high T and P

▪ Super interglacials cannot be explained by changes in orbital parameters or greenhouse gases

▪ Cause of super interglacials = ? traced to changes in ocean circulation due to disintegration events of the West Antarctic ice sheet

Summary

2.8 Million Years of Arctic ClimateChange from Lake El’gygytgyn,NE Russia – Melles et al. 2012

Pliocene Warmth, Polar Amplification,and Stepped Pleistocene CoolingRecorded in NE Arctic Russia – Brigham-Grette et al. 2013

Lake E Special issue30 manuscriptsConcerning the

Details 2013/2014

Open access!!

Thank you !

Questions? juliebg@geo.umass.edu