Biology Reference
In-Depth Information
7. Uplift of blocks within the Ecuadorian Andes Mountains by 150 m within
the past 7000 years.
8. Relict Quaternary dunes in the now humid Pantanal indicating environ-
ments periodically so dry that the protective vegetation cover was sig-
nifi cantly reduced, and strong winds caused dune movement that would
further increase desiccation.
9. Pampas plains with sand and loess younger than 2.5 Ma, suggesting wet
and drier cycles.
10. Eight sedimentary cycles of Quaternary age in the Entre Rios region of
northeastern Argentina, indicating wet/fl ooding to arid conditions.
11. Aeolian deposits, wind-blown sediments characteristic of dry conditions,
in the Hernandarias Formation of the Entre Rios region of Argentina
at 1.3-0.8 Ma, representing rainfall at 13 percent of present levels, or
100-150 mm a year.
12. Origin of some bajos (enclosed, often water-fi lled basins) in Patagonia
through erosion after vegetation was reduced during intervals colder and
drier than at present, that is, during glacial cycles.
13. Loess sediments, indicating dry conditions, alternating with swamp de-
posits in the Rosario Formation of the Pampean region of Argentina dated
at 730 kyr.
14. Evidence of extensive glaciation in what are today ice-free areas of south-
ern Chile, Patagonia, and Tierra de Fuego.
15. Presence of erosion terraces 30-80 m above present sea level on Marajó
Island, Brazil, and adjacent regions of the Amazon Basin.
16. Glacial moraines in the Cordillera de Mérida offset several tens of meters
by faulting during the Holocene.
17. Fluctuations in the abundance of mylodonts and equids in the Pleistocene
Cangahua Formation of Ecuador correlated with cold-dry cycles.
18. Evidence for extensive glaciation in the eastern cordillera of Bolivia,
in the form of moraines, tillites, and hummocky surfaces. Presumably
glacial cycles have repeated multiple times since 2 Ma and, based on the
High Plain of Bogotá data set, likely extended far downslope toward the
lowlands.
19. Snowline depression at the LGM of 200-300 m in the Junin region of
Peru, 600 m at Laguna Kollpa, Bolivia, and 100-1350 m in the Cordillera
Oriental, Peru.
20. Human populations from Brazil showing signifi cant effects of a middle
Holocene dry period.
21. Alluvial fans in the Gran Chaco of Argentina, eastern Bolivia, and south-
eastern Brazil originating in the humid phases of the Pliocene and Qua-
