Linking orography, climate, and exhumation across the central Andes

Asynchrony of Seasons: Genetic Differentiation Associated with Geographic Variation in Climatic Seasonality and Reproductive Phenology

“…That is, our estimates of the effect of precipitation asynchrony focus on explaining residual genetic differentiation unaccounted for by resistance distances, in principle separating the effect of topography from that of precipitation asynchrony on genetic divergence. However, one must bear in mind that topography also has an influence on precipitation (Changnon et al 1991;Basist et al 1994;Barnes et al 2012). For example, spatial changes from unimodal to bimodal precipitation regimes are often associated with mountain ranges (fig.…”

Cenozoic tectonostratigraphic evolution and architecture of the Central Andes in northern Chile based on the Aquine region, Western Cordillera (19°-19º30’ S).

“…In the Precordillera, Paleogene contraction and consequent erosion and denudation gave rise to the regionally f lat, erosive, Choja Pediplain unconformity (Galli, 1967). Block exhumation in the Eastern Cordillera was triggered during the late Eocene-early Oligocene (36-27 Ma) (Barnes et al, 2012), synchronic to or slightly later than this first period of contraction in the western Altiplano. …”

“…, and into the Subandean Sierras during most of the Neogene (ca. 20-0 Ma) (McQuarrie et al, 2005;Barnes et al, 2012), by means of thick-and thin-skinned, mainly east-vergent, but also doubly-vergent, fold-and-thrust systems.…”

Biodiversity from mountain building

“…Along the western margin of South America, the Andes grew into a high mountain range, whereas farther east the continent subsided and the Amazon Basin formed. Mountain and basin formation, as well as erosion, marine incursions and orographic precipitation 13,15 , together provide the nutrient-rich sediments and soils that now sustain the high species richness of Amazonia 16,17 . From its formation about 10.5 million years ago 18 , the Amazon River opened up entirely new habitats both on land and at sea.…”

“…Uplift of Earth's surface during mountain growth influences drainage patterns 11 , generating drainage divides and rivers that in turn act as bridges, barriers or species pumps 12 . Mountain uplift also affects atmospheric circulation 13 and the marine environment 14 . The Andean chain and the Amazon River are good examples of this interaction.…”