Geology of the area of Bahía Blanca, Darwin’s view and the present knowledge: a story of 10 million years

QUATTROCCHIO, M.; DESCHAMPS, C.; ZAVALA, C.; GRILL, S.; BORROMEI, A.

RAGA

Asociación Geológica Argentina

Año: 2009 vol. 64 p. 137 - 146

0004-4822

The aim of this paper is to give an updated outlook of the scenery described by Charles Darwin when he visited Bahía Blanca and surrounding areas, following the itinerary during his voyage on board HMS Beagle. Such an outlook is a state of the art of the current understanding of the Late Miocene-Holocene history in the southwestern Pampas (Argentina).Multidisciplinary results were integrated in a chronosequence chart synthesizing the suggested space-time correlation of the recognized events. Some of the studied localities covering the whole time interval represented in the area were arranged in this chart in a hypothetical E-W line crossing the Río Sauce Grande basin and the surrounding highlands. This line is also approximately the one followed in part by Darwin when riding from Bahía Blanca to Tapalqué (Tapalguen) as he crossed the region toward the Río Sauce. Paleoenviromental and paleoclimatic inferences for the last 10m.y. are also given. Paleontological studies included vertebrates, ostracods and palynomorphs. Many of the results of these investigations are the answers toDarwin´s question when he first visited the area.Keywords: Pampas, Tapalqué, Pampean Formation, Punta Alta, Red earth cliffs.