Mono Basin climate changes correlative with North Atlantic Dansgaard-Oeschger oscillations

Transcription

1 Mono Basin climate changes correlative with North Atlantic Dansgaard-Oeschger oscillations Susan Zimmerman Lawrence Livermore Nat l. Lab. Corinne Hartin RSMAS- U Miami Crystal Pearl Queens College,CUNY Stephanie Searle Columbia University Sidney Hemming Columbia/LDEO Gary Hemming Queens College, CUNY Dennis Kent Rutgers U/LDEO Wilson Creek Formation Type Section

2 Talk outline: 1. Mono Basin, California 2. Lake-level indicators Low-resolution: physical stratigraphy High-resolution: CaCO 3 3. Wilson Creek Formation Age Control 4. Correlation to regional & global records Santa Barbara Basin Greenland

3 N Mono Lake Owens Lake

4 Mono Lake, CA -salinity 80g/L, ph ~10 -unusually isolated hydrological basin -direct water and sediment input from Sierras -excellent exposures of the late Pleistocene deeplake sediments ( ) -19 ash layers for intrabasin correlation

5 Late Pleistocene Wilson Creek Formation Laminated Dropstones: Ostracodes: silts: ~ 7 m total height SEM photos: Neil Tibert, U Mary Wash. Alluvial gravels below unconformity

6 Lajoie s Mono Lake: Total: 68 stratigraphic columns, plus Paoha Island

7 E D B A

8 Three periods of generally higher lake level: Marker Sequences D/E, C, A But, a relatively low-resolution record... Lajoie (1968)

9 at Mono Lake, high CaCO 3 deposition = high lake level Benson et al. (1998)

10 N weight % CO3 O-isotopes Owens Lake closed spilling Bischoff et al. (1997)

11 Owens Lake sill height = 60 m Mono Lake sill height = 300 m

12 Tufa tower near modern spring at Mono Lake

13 at Mono Lake, high CaCO 3 deposition = high lake level Spliced from South Shore Benson et al. (1998)

14 Key question: When?? CaCO 3 (generally) a whole-lake signal confirmed with replicate sections at South Shore and Warm Springs

15 Radiocarbon and Ar/Ar constraints stratigraphic height (cm) radiocarbon leached radiocarbon Ar/Ar age (calendar ka) Ashes: Radiocarbon: Lajoie (1968) C dates (ostracodes) Benson et al. (1990) C dates (ostracodes, tufa, crusts, nodules) Kent et al. (2002) C leaches (crusty & clean ostracodes, nodules) Ar/Ar: Chen et al. (1996) 40 Ar/ 39 Ar dates (sanidines in Ashes 5 & 12) Kent et al. (2002) - 40 Ar/ 39 Ar dates sanidines in Ashes 8, 15, 16

16 Mono Basin paleointensity-based age model (Zimmerman et al. 2006, EPSL) Relative paleointensity (NRM/IRM) measured on type and South Shore outcrops stacked record constrained by radiometric ages Base <74 ka (MIS 5-4 boundary) Correlation to GLOPIS = GISP2 chronology w/errors estimated

17 Control of lake level by large-scale climate variations: What about correlatives to millennial-scale events?? Martinson et al. (1974) Berger (1978) Lajoie (1968) Benson et al. (1998) Bischoff et al. (1997)

18 Dansgaard-Oeschger correlatives at Mono Lake?

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20 Global D-O correlatives warmer Greenland wetter Venezuela warmer Pacific CB Peterson et al. (2000) SBB Hendy and Kennett (2000) wetter Mono Basin

21 Inter-Tropical Convergence Zone (ITCZ) as D-O teleconnector

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25 Correlation of the excursions at Mono Lake and Laschamp does not exclude a directional excursion at 34 ka Paleointensity lows/ cosmogenic nuclide peaks do not require a directional excursion! ODP 919 (Irminger Basin) Channell (2006) St-Onge et al. (2003)

26 Estimation of error: 3 stacks + 3 records; all on GISP2 age model 10 of 14 Mono-GLOPIS tie-points identified 2-sigma deviation of each point in six curves

27 Lajoie s stratigraphy with Benson s data: unlike at Owens Lake high lake = high carbonate weight % CO3 O-isotopes Owens Lake closed spilling Bischoff et al. (1997) Lajoie (1968) Benson et al. (1998)

28 Mono Lake paleointensity stack: Zimmerman et al. (2006) EPSL 1. South Shore (SS) correlated to Wilson Creek (WC) 2. 5-point running mean calculated 3. Error bars = standard deviation of five points 4. Comparison to Liddicoat & Coe (1979)

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31 VADM GISP2 age (ka) GLOPIS Mono RPI sed rate (cm/kyr) RPI tie-points Wilson Creek South Shore GISP2 age (ka)

32 A Elevation (masl) 2155m 2195m

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39 Lundy Lee Vining Bloody Parker Rush/ Reversed Creek

40 Correlation of Mono Lake to GLOPIS: Laschamp RPI chronology: n Wilson Creek (c Mono Lake O- isotopes weight % CO3 Deposition begins ~67 ka Sedimentation rates 6-34 Owens cm/kyr Lake (proxy records flux-corrected) 14 C residue ML excursion = Laschamp

41 Control of lake level by 100-kyr and 20-kyr climate cycles: Martinson et al. (1987) Laskar (1990) Lajoie (1968)