The Ordovician of southern South America

Abstract

Early Paleozoic rocks are widespread, superbly exposed, and reach several thousand metres thick in southern South America. A largely quadripartite geotectonic subdivision of this huge area encompasses: (1) intracratonic basins forming the sedimentary cover of the Amazonian craton (Brazilian collage), 2) clastic platform surrounding the Amazonian craton and the Pampia Terrane (Sierras Subandinas and Cordillera Oriental), (3) subduction-related parautochthonous volcanic arcs and associated volcano-sedimentary basins (Puna-Famatina arc), and (4) crustal fragments accreted to the proto-Andean margin of Gondwana (e.g. Cuyania Terrane). In this context, disparity in geodynamic histories, preserved record, and geological knowledge is remarkable.. Biostratigraphical frameworks allow the recognition of global chronostratigraphical Ordovician subdivisions with fairly good resolution in the Early and Middle Ordovician of the Precordillera and the Early Ordovician of the Cordillera Oriental of Argentina. In Sierras Subandinas and Cordillera Oriental of Bolivia the Ordovician statigraphy is almost complete, though these extensive regions are still poorly known. As well, trilobite-rich assemblages from the Cordillera Oriental and brachiopod-rich ones from Precordillera and Famatina offer a remarkable template for dissecting regionally different scenarios underlying Ordovician diversifications.. Overall, a more complete knowledge of this key area of Gondwana will certainly enhance our understanding of the global dynamics during the Ordovician.

Lower Tremadocian (Ordovician) lingulate brachiopods from the Central Andean Basin (NW Argentina) and their biogeographical links

“…Four distinct lower Palaeozoic sedimentary domains can be recognized in southern South America (Benedetto 2018, Waisfeld et al 2023: (1) the intracratonic se dimentary cover of the Amazonian Craton in Brazil, 2) the clastic platforms surrounding the Amazonian Craton and the Pampia terrane, through Peru, Bolivia, and Northwestern Argentina, known as the Central Andean Basin (CAB), (3) the early Palaeozoic subduction-related parautochthonous volcanic arcs and associated volcanosedimentary basins marginal to Gondwana continent (e.g. the Famatina Basin), and (4) the crustal fragments accreted to the proto-Andean margin of Gondwana, of which the better known is the Laurentian-derived Cuyania (or Precordillera) terrane.…”

A journey through the Ordovician System around the world

“…The southern part of South America (Argentina, Bolivia, Brazil, Chile and Paraguay) represents a substantial portion of Gondwana. Waisfeld et al (2023) describe the thick, extensive and unequally investigated Ordovician successions occurring in four main areas.…”

First Record of Cryptospores from the Late Ordovician–Early Silurian of Colombia: New Contribution to the Understanding of Plant Terrestrialization

“…Late Ordovician cryptospore assemblages in South America are still scarce and mainly circumscribed to Argentina. Hirnantian cryptospores have been recorded from the three geological provinces that constitute the Central Andean Basin in northwestern Argentina (Waisfeld et al , 2023). They come from the Salar del Rincón Formation, in the Puna (Rubinstein & Vaccari, 2004), the Zapla Formation, in the Sierras Subandinas (Rubinstein, 2005), and the Caspalá Formation, in the Cordillera Oriental, the latter dated as Hirnantian or probably Katian (Rubinstein et al , 2016).…”