Research ArticlePALEONTOLOGY

Neogene precipitation, vegetation, and elevation history of the Central Andean Plateau

See allHide authors and affiliations

Science Advances  28 Aug 2020:
Vol. 6, no. 35, eaaz4724
DOI: 10.1126/sciadv.aaz4724
  • Fig. 1 Geographic location and precipitation of the CAP.

    Geographic location of the CAP, summary of paleoprecipitation estimates from previous studies. (A) Topographic map showing the location of the CAP and the location of the Descanso-Yauri Basin (black triangle) in the Peruvian Andes. Gray triangles indicate the geographic location of sites from the modern palynological dataset and their environmental distribution (elevation and mean annual precipitation). m.a.s.l., meters above sea level. (B) Simulated precipitation based on the ECHAM model when the CAP had 100% (600 to 700 mm/year) and 40% (100 to 200 mm/year) of its current elevation [figure taken from (9)].

  • Fig. 2 Geological setting of the Descanso-Yauri Basin.

    (A) Geologic map for the Descanso-Yauri Basin, showing where the samples were collected [modified from (8)]. (B) Stratigraphic column for El Descanso Formation, including members A, B, and C [modified from (8)]. Bars next to the samples correspond to the uncertainty in the stratigraphic depth for the sample or group of samples. Undulating line represents the unconformity between members B and C. (C) Photographs of some of the macro- and microfossils collected for this study. From top to bottom: Fossil log with 7 m of length, legume fossil wood anatomy (scale bar, 1 mm), Ribes sp. leaf (scale bar, 10 mm), and Podocarpus sp. pollen (scale bar, 10 μm). Photo credits: First and second rows: C. Martínez, Cornell University and Smithsonian Tropical Research Institute (STRI); third row: A. Aliaga, Museo de Historia Natural de Lima; fourth row: J. E. Moreno, STRI.

  • Fig. 3 Environmental space.

    Estimated environmental space for the middle to late Miocene (Member B; gray), the early Pliocene (Member C; red), and the Holocene (blue) at Descanso-Yauri Basin, showing probability density functions for precipitation (right) and elevation (bottom). These estimations are based on a mixture of micro- and macrofossil sets.

  • Fig. 4 Floristic comparison.

    Comparison of palynofloras from members B and C with extant pollen data from South America. The density plots show the probability distribution of the CDI (0 = least dissimilar; 1 = most dissimilar). Green curves represent CDI for within-biome comparison for modern altitudinal ranges (lower montane, upper montane, and puna). (A) Comparison for lower montane sites: Gray curve represents CDI between the fossil assemblage from the Miocene Member B and the modern lower montane sites. (B) Comparison for upper montane sites: Gray curve represents CDI between the fossil assemblage from the Miocene Member B and the modern upper montane sites. (C) Comparison for puna sites: Red curve represents CDI between the fossil assemblage from the Pliocene Member C and the modern puna sites.

  • Table 1 Floristic comparison.

    Floristic comparison of pollen records from members B and C and modern pollen records from sites located along the Central and Northern Andes (Fig. 1A). The altitudinal gradient includes sites from lowland, lower montane, upper montane, and puna ecosystems. The comparison was done using the CDI (0 = least dissimilar; 1 = most dissimilar).

    Altitudinal
    range
    PalynofloraFirst
    quartile
    MedianThird
    quartile
    Puna
    3400–4700 m
    Modern0.08270.16730.3006
    Member C versus
    modern
    0.12870.20700.3357
    Member B versus
    modern
    0.37880.56490.7125
    Upper
    montane
    2400–3400 m
    Modern0.10040.17580.3147
    Member C versus
    modern
    0.25380.44950.6387
    Member B versus
    modern
    0.49390.70690.8423
    Lower
    montane
    1200–2400 m
    Modern0.17830.30710.4420
    Member C versus
    modern
    0.60850.76360.8770
    Member B versus
    modern
    0.66190.80200.9077
    Lowlands
    0–1200 m
    Modern0.17910.30930.4361
    Member C versus
    modern
    0.61000.77860.8783
    Member B versus
    modern
    0.66520.80800.9087

Supplementary Materials

Stay Connected to Science Advances

Navigate This Article