Evaluating the influence of tectonics on the genetic lineage distribution of Nothofagus in contrasting areas of the Patagonian Andes

BECHIS F.; ACOSTA M. C.; MATHIASEN P.; PREMOLI A. C.; THOMSON S.; RAMOS V. A.

Punta Arenas

Congreso; VIII Southern Connection Congress; 2016

Southern Connection

TheNorthern and Southern Patagonian Andes show important differences regardingtheir geological evolution during the Cenozoic Era, which began 66 millionyears ago. These include important variations in the altitude, style and timingof the mountains? uplift, and the Pacific vs. Atlantic origin of marine connections,among others. Coincidentally, the geographic distribution of the geneticlineages and haplotypes found for all species within the genus Nothofagusalsoshow important variations between the southern and northern sectors of thePatagonian Andes. Molecular dating has revealed that divergences of theancestral lineages took place in different times during the Cenozoic associatedwith paleogeographic changes related to geologic and climatic factors. These previousstudies proved that there is a strong link between the tectonic and biologicalevolution in Patagonia. In this contribution, we outline major latitudinal differencesin the geologic evolution of the Patagonian Andes in order to identify key paleogeographicelements that could have acted as barriers, filters or corridors for thedispersion and divergence of Nothofagus species during the Cenozoic.Furthermore, we explore if the available genetic data could help to evaluatecompeting geological hypotheses, including the location of the Atlantic-Pacificmarine connections, or the timing of the Andean uplift. We will particularlyfocus on the segment between 41° and 42°S, where a complete set of previous andnew ages obtained from different techniques (apatite fission trackthermochronology and U-Pb LA-ICPMS geochronology) allows a precise dating ofthe tectonic and paleogeographic evolution, favoring its comparison andintegration with the genetic data.