Evidence of Holocene climate change in northeastern Baffin Baybased on sedimentological analyses and dinoflagellate cyst assemblages

Myriam Caron1,2, André Rochon1, Guillaume St-Onge1, Jean-Carlos Montero-Serrano11 Ins�tut des sciences de la mer de Rimouski, Canada Research Chair in Marine Geology, Université du Québec à Rimouski et GEOTOP, 310 allée des Ursulines, Rimouski, Québec, G5L 3A1, Canada

2 myriam.caron03@uqar.ca

INTRODUCTION

OBJECTIVES1) Track changes in sediment inputs and transport pathways2) Es�mate the evolu�on of sea surface condi�ons (temperature, salinity, sea-ice cover dura�on, produc�vity)3) Document ocean, ice sheet and climate interac�ons in Baffin Bay during the Holocene

• Two major ocean currents meet in the north of Baffin Bay (Tang et al., 2004): → Baffin Island Current (Arctic waters) → West Greenland Current (mixture of Atlantic and Arctic waters)

• Climatic and oceanographic changes occurred since the last glaciation, and through the Holocene.

Ice Sheet

Glacialmargin

Sea iceIceberg

Turbidity current

Debris flow

MeltwaterplumeIce Rafted Debris

Sea surface productivity

Iceberg calving

Hemipelagicsedimentation

Eolian input

Dinoflagellates

Deposition on the sea floor

Cysts

Dinocysts record sea-surface condi�ons

when they fossilize in the sediment

Mul�ple sediment transport processes on the con�nental shelf and slope when associated to ice

sheets

• During the last glacial maximum, Baffin Bay was surrounded by three large ice sheets: the Laurentian, Innuitian and Greenland ice sheets (Dyke et al., 2002).

• Presence of cross-shelf troughs on the continental shelves (Aksu and Piper, 1987).

• Sub-glacial erosion transports sediments across the continental shelf → recording of sediment provenance.

• Glacial erosion triggers different transport and depositional processes (O’Cofaigh et al., 2013)

72°N

74°N

76°N

78°N

80°N

82°N

80°W 70°W 60°W 50°W

Oce

an D

ata

View

2500 m

2000 m

1500 m

1000 m

500 m

300 m

200 m

100 m

80 m

60 m

40 m

20 m

5 m

GreenlandIce sheet

Karrat Group

Rinkian mobile belt

Thule Group

Upernavik

Melville Bugt

Uummannaq

Kane Basin

Baffin Island

EllesmereIsland

Lancaster sound

Nares

Strai

t

Age

Basalts (mafic)Limestone and

dolomite

Silicoclastic rocks(Quartzarenites)

Gneiss andsilicoclastic rocks

Granitesand orthogneiss

Gneisses Archaean

Prec

ambr

ian

Shie

ld

Arch

ean

Prot

eroz

oic

Pale

ozoi

c

BaffinBay

Kane2B

210

204

Did the sediment record the major climatic variations of the deglaciation and the Holocene?

What werethe impacts of these changes on the sediment input?

Simplified geological mapmodified a�er Simon et al. (2014)

METHODS• Three sedimentary cores collected on the northwestern Greenland margin (2014 Arc�cNet expedi�on - Leg1b)• The chronology of the sediment cores was constrained by combining paleomagne�c analyses with AMS-14C ages• Physical proper�es acquired with CT-Scan (X-ray digital image) and MSCL (high-resolu�on images, sediment color, magne�c suscep�bility)• Grain size (laser granulometry) and magne�c proper�es (cryogenic magnetometer) analyses • Quantitative X-ray diffrac�on (qXRD) and X-ray fluorescence (XRF): bulk mineralogical and geochemical sediment proper�es• Palynological analyses using the modern analog technic (MAT) to reconstruct the sea-surface condi�ons based on dinoflagellate cyst assemblages

AMD14-210AMD14-204

0 2 4 6 8 10

600

400

200

0

cal ka BP

Dep

th (c

m)

0 2 4 6 8 10

600

500

400

300

200

100

0

cal ka BP

Dep

th (c

m)

0 2 4 6 8 10

400

300

200

100

0

cal ka BP

Dep

th (c

m)

RESULTS

DISCUSSION

DeglacialHolocene

1

2a

2b

2c

3a

3b

1

2a

2b

3

2

3a

3b

Coarse sandsSandsCoarse siltsMedium siltsFine siltsClaysLithology

Dep

th (c

m)

0

100

200

300

400

428

CTScan

0

100

200

300

400

500

577

CTScan

Lithology%

0 50 1000

100

200

300

400

500

600

700

743

CTScan

Lithology%

0 50 100

Lithology%

0 50 1000 200 400

Magnetic susceptibility

(x10-5 SI)

0 275 550

Magnetic susceptibility

(x10-5 SI)

0 2 4a*

- green-red +

0 1 2a*

- green-red +

-1 0 1 2a*

- green-red +

0 100 200

Magnetic susceptibility

(x10-5 SI)

0 1000 2000

Density(CT number)

0 750 1500

Density(CT number)

300 550 800

Density(CT number)

AMD14-Kane2B AMD14-210 AMD14-204

• A significant downcore variability is observed on these three cores and different units are determined based on this variability: Unit 1: Glaciomarine sedimenta�on, ice-proximal Unit 2: Massive to laminated hemipelagic sedimenta�on, ice-distal Unit 3: Hemipelagic sedimenta�on, ice-distal

24

68

10

1214

16

Cal

cite

(%)

0 5 10 15 20 25Plagioclase (%)

141516171819202122

Qua

rtz (%

)

25 26 27 28 29 30 31 32 33Plagioclase (%)

AMD14-Kane2B AMD14-210 AMD14-204

Postglacial Deglacial

9 10 11 12 13 14 15 16 17K-Feldspar (%)

14

16

18

20

22

24

26

Qua

rtz (%

)

0

10

20

30

40

50

Ran

ge %

Quartz K-Feldspar Plagioclase Calc. + Dol. Micas Clay

Kane 2B

204

210

Distribution of minerals within the cores:

AMD14-Kane2B

Dep

th (c

m)

0

100

200

300

400

428

CTScan 0 5000 10000

Dinocyst concentration(cyst/cm3)

HeterotrophAutotroph

0

100

200

300

400

500

600

700

743

CTScan 0 12500 25000

Dinocyst concentration(cyst/cm3)

AMD14-204

I

I

II

III

II

III

Cyst of Pentapharsodinium

dalei

Operculodiniumcentrocarpum

Spiniferiteselongatus/frigidus

Islandinium minutum

Brigantediniumsp.

Echinidiniumkaraense

Islandiniumminutum

• Sediment provenance (detrital inputs): AMD14-Kane2B: mainly derived from Paleozoic carbonate-bearing rocks and more Proterozoic granitic sources in unit 2 (2a and 2B) AMD14-210 and AMD14-204: mainly derived from granite and gneiss from the Precambrian Shield

• Palynological results → three dinocyst assemblage zones determined: Assemblage I: low dinocyst concentra�on, heterotrophs dominate Assemblage II: marked by Operculodinium centrocarpum and Spiniferites elongatus dominance (AMD14-204) or occurrence (AMD14-Kane2B) and increasing dinocyst concentra�on Assemblage III: marked by Pentapharsodinium dalei dominance (AMD14-204) or occurrence (AMD14-Kane2B) and a decreasing concentra�on at the top of the cores

AM

D14

-Kan

e2B

War

m a

nd c

old

dino

cyst

s

0

10

20

0 2 4 6 8 10

% Gonyaulacal

Age cal ka BP

0

35

70

% Brigantedinium sp.

0

35

70% O. centrocarpum

0

17,5

35

% Islandinium minutum

AM

D14-204

Warm

and colddinocysts

1

2

3

4

Quartz/Plagioclase22

27

32

Quartz (%

)

AM

D14-K

ane2B

0,45

0,65

0,85

Qua

rtz/

Plag

iocl

ase

12

17

22

Qua

rtz

(%)

AM

D14

-204

0,1

0,4

0,7

Cla

y/Si

ltA

MD

14-2

10

0,45

0,6

0,75

Quartz/Plagioclase14

20

26

Quartz (%

)

AM

D14-210

Age cal ka BP

-32

-29,5

-27

0 2 4 6 8 10

18O

Cam

p Ce

ntur

y

-35

-34

-33

-32

-31

-30

-29

-28

-27

0 2000 4000 6000 8000 10000

18O

(‰) C

amp

Cent

ury

DeglaciationHolocene ThermalMaximumNeoglaciation

warmer

surfacewaters

warmer

surfacewaters

0

2

4

6

8

10

Age cal BP

Moro

s et a

l. (20

16)

Jenn

ings e

t al. (

2011

)St

-Ong

e and

St-O

nge (

2014

)

Leva

c et a

l. (20

01)

Pern

er et

al. (2

012)

Jenn

ings e

t al. (

2014

)

0 10 200

2

4

6

8

10

AMD14-Kane2B% Gonyaulacals

Age

cal B

P

Knud

sen e

t al. (

2008

)

Kraw

czyk

et al

. (201

7)

14 20 26

AMD14-210Quartz (%)

0 50 100

AMD14-204Heterotroph (%)

WEST GREENLANDSMITH SOUND / NARES STRAIT

Deglaciation

Holocene Therm

alM

aximum

Neoglaciation

-32 -29,5 -27

-35

-34

-33

-32

-31

-30

-29

-28

-27

02

00

04

00

06

00

08

00

01

00

00

18O (‰) Camp Century

Ag

e (ca

l BP

)

Vinther et al. (2009)18O Camp century (‰)

• Lithological units 1 and 2 show a mainly deglacial (glaciomarine) sedimenta�on strongly affected by meltwater inputs and ice-ra�ing. This units are correlated to the dinocyst assemblage zone I, characterized by cold sea-surface temperature and an extended sea-ice cover. Thus, this period is associated to the Deglacia�on.

• Finally, the dinocyst assemblage III suggests the establishment of modern sea-surface conditions and a cooling trend after 3 cal ka BP. This period is associated to the Neoglaciation.

• Holocene Thermal Maximum occurs earlier in the northernmost part of Baffin Bay compared to other parts of the Arctic (e.g., Moros et al., 2016; Jennings et al., 2014)

• Lithological unit 3 is characterized by hemipelagic sedimenta�on which indicates more stable condi�ons than units 1 and 2. Dinocyst assemblage II suggests higher produc�vity and generally warmer sea-surface condi�ons. This period is associated to the Holocene Thermal Maximum.

ACKNOWLEDGMENT & REFERENCESWe thank the captain, officers, crew and scientists on board the CCGS Amundsen for the recovery of cores AMD14-204, AMD14-210 and AMD14-Kane2B. We also thank Quentin Beauvais and Marie-Pier St-Onge for their technical support. This study was supported by the CREATE ArcTrain program (NSERC). © Q. Duboc for the background photo.REFERENCES: Aksu and Piper, 1987, Late Quaternary sedimentation in Baffin Bay. Can. J. Earth Sci. 24, 1833–1846. Dyke et al., 2002, The Laurentide and Innuitian ice sheets during the Last Glacial Maximum. Quat. Sci. Rev. 21, 9–31. Jennings et al. 2014, Paleoenvironments during Younger Dryas-Early Holocene retreat of the Greenland Ice Sheet from outer Disko Trough, central west Greenland. J. Quat. Sci. 29, 27–40. Moros et al., 2016, Surface and sub-surface multi-proxy reconstruction of middle to late Holocene palaeoceanographic changes in Disko Bugt, West Greenland. Quat. Sci. Rev. 132, 146–160. Ó Cofaigh et al., 2013, Glacimarine lithofacies, provenance and depositional processes on a West Greenland trough-mouth fan. J. Quat. Sci. 28, 13–26. Simon et al., 2014, North-eastern Laurentide, western Greenland and southern Innuitian ice stream dynamics during the last glacial cycle. J. Quat. Sci. 29, 14–26. Tang et al., 2004, The circulation, water masses and sea-ice of Baffin Bay. Prog. Oceanogr. 63, 183–228. Vinther et al., 2009, Holocene thinning of the Greenland ice sheet. Nature 461, 385–388.

CONCLUSIONSThe specific varia�ons of almost all proxies measured in this study are synchronous with other regional records, suppor�ng the following hypotheses: (1) the Greenland Ice Sheet fluctua�ons are mainly driven by changes in the intensity of the West Greenland Current, themselves related to Holocene climate variability and; (2) the Holocene is subdivided into three main clima�c periods: the end of the deglacia�on, the Holocene Thermal Maximum and the Neoglacia�on.