Research ArticleCLIMATOLOGY

Lake Tauca highstand (Heinrich Stadial 1a) driven by a southward shift of the Bolivian High

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Science Advances  29 Aug 2018:
Vol. 4, no. 8, eaar2514
DOI: 10.1126/sciadv.aar2514
  • Fig. 1 Paleoglacial extent of glacial cover during the Lake Tauca highstand (16.5 to 14.5 ka BP) at the nine paleoglaciated mountains where a moraine synchronous with the Lake Tauca highstand was identified.

    (A) Nevado Sajama (data from this study). (B) Cerro Pikacho (data from this study). (C) Cerro Luxar (data from this study). (D) Cerro Uturuncu (59). (E) Cerro Tunupa (17, 25). (F) Cerro Tambo (data from this study). (G) Cerro Azanaques (27). The additional feature mapped here is the Challapata fan delta and its boulder field (light orange; see section S1.2.1). (H) Zongo Valley. The white arrows indicate the former ice-flow direction (60). (I) Laguna Aricoma (61). Aerial photographs are from Google Earth. Paleo-ELAs were reconstructed using the AAR method (see the Supplementary Materials for more details).

  • Fig. 2 Map of the Altiplano basin showing locations of the nine paleoglaciated sites and associated geochronological constraints (3He and 10Be dating in thousand years BP) and ELA (in meters above sea level).

    CRE ages (presented in age probability density function plots) at each site (yellow points) constrain the extent of glacier cover coeval with the Tauca highstand (16.5 to 14.5 ka BP, above 3760 m, dark blue contour on the map, and vertical blue bands on the age plots). The horizontal axis of each graph shows the CRE age (in thousand years before 2010). The blue number in each age plot is the associated ELA in meters above sea level (see the Supplementary Materials)

  • Fig. 3 Annual precipitation maps for the Altiplano—modern and Tauca highstand.

    (A) Current annual rainfall over the Altiplano (36). White dots, sample sites; blue contours, Lakes Titicaca and Tauca. (B) Tauca highstand annual rainfall derived from our reconstruction. (A) and (B) share the same color scale. (C) Difference between the Tauca and modern annual rainfall. (D) Rainfall amplification during the Lake Tauca highstand compared to Present. Precip., precipitation. (E) Relative uncertainty (uncert.) in the precipitation results (uncertainties in the present-day climate and ELA were propagated using Monte Carlo methods; see the Supplementary Materials). (F) Hydrological and glacial map.

  • Fig. 4 Paleoclimatic implications for South America during HS1—Tauca highstand.

    Left: Modern features of South American climate with particular focus on the summer monsoon. SWW, southern westerly winds; AMOC, Atlantic meridional overturning circulation; ITCZ, intertropical convergence zone; SALLJ, South American low-level jets. The colored background shows the mean annual rainfall. Asterisk indicates the color scale truncated at 3500 mm. Blue contours show the DJF/annual precipitation ratio. Precipitation data are from ERA-Interim (57), with mean values between 1979 and 2016. Right: Modification of South American climate during the second half of HS1, as suggested by our data. Compared to present, the BH is intensified and located further south. The SACZ is intensified, and the SWW are also displaced southward. These features all enhanced the transport of moisture onto the Altiplano. Concurrently, the ITCZ shifted southward, and AMOC intensity was reduced. Blue and red symbols correspond to climatic records that report wetter and drier conditions, respectively, during the Tauca highstand. Circles, δ18O results from speleothems; rectangles, δ18O from lacustrine or marine cores. Points 8, 10, and 11 are locations of the Jaragua, Paixão, and Lapa Sem Fim speleothems, respectively (14, 15). White star indicates the location of a core that implies a southward shift of the SWW (44). See the Supplementary Materials for all site names and references.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/8/eaar2514/DC1

    Section S1. Geological settings

    Section S2. Methods

    Section S3. Results

    Section S4. Method sensitivity and result accuracy

    Fig. S1. Seasonality of the annual rainfall over South America.

    Fig. S2. Locations of the different sites in the scope of this study.

    Fig. S3. Sampled moraines in the Zongo Valley.

    Fig. S4. Sampled moraines and sample locations on Cerro Azanaques.

    Fig. S5. Sampled moraines and sample locations on Cerro Tambo.

    Fig. S6. Sampled moraines and sample locations on Cerro Pikacho.

    Fig. S7. Sampled moraines and sample locations on Nevado Sajama.

    Fig. S8. Sampled moraines and sample locations on Cerro Luxar.

    Fig. S9. Moraine studied in (59) on Cerro Uturuncu.

    Fig. S10. The Tunupa glacial features studied in (17).

    Fig. S11. Moraine studied in (61) at Laguna Aricoma.

    Fig. S12. Calibration of the AAR value from the GLACIOCLIM-IRD glaciological data set (31, 32).

    Fig. S13. Comparison between the PDD and the Condom et al. (33) methods to reproduce the ELA of six High Andes tropical glaciers (determined from toe-to-headwall altitude ratio and AAR).

    Fig. S14. Location of the temperature and precipitation stations relative to the glacial valleys.

    Fig. S15. Snow management workflow in the lake model.

    Fig. S16. Workflow for precipitation field reconstruction during the Tauca highstand.

    Fig. S17. Accuracy of the interpolated rainfall grid.

    Fig. S18. Moraine age computations and identification of glacial extents coeval with the Tauca highstand at Cerro Azanaques, Cerro Tambo, Cerro Pikacho, and Cerro Uturuncu.

    Fig. S19. Moraine age computation and identification of glacial extents coeval with the Tauca highstand for the sites of Cerro Luxar, Cerro Tunupa, Zongo Valley, Laguna Aricoma, and Nevado Sajama.

    Fig. S20. Influence of the scaling scheme on the CRE age results.

    Fig. S21. Comparison of the DJF temperature from station data (37) and the New et al. (36) data set.

    Fig. S22. Sensitivity of the ELA-P-T relation.

    Fig. S23. Glacier retreat at Cerro Tambo between the Lake Tauca highstand and the consecutive deglaciation.

    Fig. S24. Lake Tauca highstand annual rainfall reconstruction using a spatially variable AAR compared to a fixed one.

    Table S1. Present annual rainfall and mean temperature at the studied sites.

    Table S2. 3He CRE age results on and Nevado Sajama, Cerro Pikacho, and Cerro Tunupa.

    Table S3. 3He CRE age results on Cerro Luxar y Uturuncu.

    Table S4. 10Be CRE age results on Cerro Tambo, Azanaques, at the Zongo Valley, and at Laguna Aricoma.

    Table S5. Details of our new 10Be measurements on Cerro Tambo, Azanaques, and at the Zongo Valley.

    Table S6. ELA of the glacial extents coeval with the Tauca highstand and associated paleoprecipitation results.

    Table S7. Compilation of paleoclimatic studies related to SASM dynamics during HS1 (5, 1316, 4951) (107, 112114).

    References (62114)

  • Supplementary Materials

    This PDF file includes:

    • Section S1. Geological settings
    • Section S2. Methods
    • Section S3. Results
    • Section S4. Method sensitivity and result accuracy
    • Fig. S1. Seasonality of the annual rainfall over South America.
    • Fig. S2. Locations of the different sites in the scope of this study.
    • Fig. S3. Sampled moraines in the Zongo Valley.
    • Fig. S4. Sampled moraines and sample locations on Cerro Azanaques.
    • Fig. S5. Sampled moraines and sample locations on Cerro Tambo.
    • Fig. S6. Sampled moraines and sample locations on Cerro Pikacho.
    • Fig. S7. Sampled moraines and sample locations on Nevado Sajama.
    • Fig. S8. Sampled moraines and sample locations on Cerro Luxar.
    • Fig. S9. Moraine studied in (59) on Cerro Uturuncu.
    • Fig. S10. The Tunupa glacial features studied in (17).
    • Fig. S11. Moraine studied in (61) at Laguna Aricoma.
    • Fig. S12. Calibration of the AAR value from the GLACIOCLIM-IRD glaciological data set (31, 32).
    • Fig. S13. Comparison between the PDD and the Condom et al. (33) methods to reproduce the ELA of six High Andes tropical glaciers (determined from toe-to-headwall altitude ratio and AAR).
    • Fig. S14. Location of the temperature and precipitation stations relative to the glacial valleys.
    • Fig. S15. Snow management workflow in the lake model.
    • Fig. S16. Workflow for precipitation field reconstruction during the Tauca highstand.
    • Fig. S17. Accuracy of the interpolated rainfall grid.
    • Fig. S18. Moraine age computations and identification of glacial extents coeval with the Tauca highstand at Cerro Azanaques, Cerro Tambo, Cerro Pikacho, and Cerro Uturuncu.
    • Fig. S19. Moraine age computation and identification of glacial extents coeval with the Tauca highstand for the sites of Cerro Luxar, Cerro Tunupa, Zongo Valley, Laguna Aricoma, and Nevado Sajama.
    • Fig. S20. Influence of the scaling scheme on the CRE age results.
    • Fig. S21. Comparison of the DJF temperature from station data (37) and the New et al. (36) data set.
    • Fig. S22. Sensitivity of the ELA-P-T relation.
    • Fig. S23. Glacier retreat at Cerro Tambo between the Lake Tauca highstand and the consecutive deglaciation.
    • Fig. S24. Lake Tauca highstand annual rainfall reconstruction using a spatially variable AAR compared to a fixed one.
    • Table S1. Present annual rainfall and mean temperature at the studied sites.
    • Table S2. 3He CRE age results on and Nevado Sajama, Cerro Pikacho, and Cerro Tunupa.
    • Table S3. 3He CRE age results on Cerro Luxar y Uturuncu.
    • Table S4. 10Be CRE age results on Cerro Tambo, Azanaques, at the Zongo Valley, and at Laguna Aricoma.
    • Table S5. Details of our new 10Be measurements on Cerro Tambo, Azanaques, and at the Zongo Valley.
    • Table S6. ELA of the glacial extents coeval with the Tauca highstand and associated paleoprecipitation results.
    • Table S7. Compilation of paleoclimatic studies related to SASM dynamics during HS1 (5, 1316, 4951) (107, 112114).
    • References (62114)

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