Integrated study of fauna and microflora from the Early Devonian (Pragian?Emsian) ofnorthwestern Argentina

NOETINGER, S.; DI PASQUO, M.M.; ISAACSON, P.; ACEÑOLAZA, G.F.; VERGEL, M.M.

Historical Biology An International Journal of Paleobiology

Taylor & Francis

Lugar: Wales; Año: 2015 p. 1 - 17

0891-2963

The Devonian System in northern Argentina has been known for some time, but details of its lithologies, biostratigraphy, organic microfossils, invertebrate and ichnofossils have not been presented in a comprehensive study. Palynological and macrofossil associations from the Baritú and Porongal formations at the Zenta Range, Eastern Cordillera, Argentina are described. A new species of cryptospore is designated and the stratigraphical record of the ichnogenus Psammichnites isp. is extended for South America. The stratigraphic distribution of the palynomorphs suggests a time span from the ?late Lochkovian to Pragian - earliest Emsian, but the co-occurrences of key invertebrates, narrow the age of the beds to the late Pragian and early Emsian. The data presented herein suggest a proximal shoreface ? foreshore depocenter during this time range for the Zenta region. The contraction phase of the basin during the middle Pragian and Emsian is evidenced by the sand bodies at the top of the column and the higher supply of terrigenous components. During this regression a low diversity Malvinokaffric Realm brachiopod assemblage occurs, with a domination of Australospirifer hawkinsi. The outnumber of A. hawkinsi during this regression is coeval with the first decline of the Malvinokaffric Realm in the neighbouring Paraná basin.