Palynology of the Iscayachi Formation (Cambro-Ordovician) from the Cordillera Oriental of Southern Bolivia: New data from the western margin of Gondwana

VERGEL, M.M., ARÁOZ, L.,ACEÑOLAZA, G.F.

Geológica Acta

Instituto Jalme Almera - CSIC

Lugar: Barcelona; Año: 2010

1695-6133

The first Late Cambrian aged palynomorph association of Bolivia is presented. Material comes from the Cambro-Ordovician Iscayachi Formation cropping out in the antenna of the Sierra de Sama, Tarija department, southern Bolivia. The palynomorph assemblage, being included in the Parabolina (Neoparabolina) frequens argentina trilobite biozone. It is composed by Acanthodiacrodium spp., Cristallinium cambriense (Slaviková) Vanguestaine, Cymatiogalea cf. aspergillum Martin, C. velifera (Downie) Martín, C. virgulta Martin, Dasydiacrodium spp., Eliasum llaniscum Fombella, Impluviculus multiangularis (Umnova) Volkova, Ladogella rommelaerei (Martín) Di Milia, Ribecai and Tongiorgi, Ladogella sp., Leiofusa sp., Leiosphaeridia sp., Lophosphaeridium sp., Lusatia? sp., Micrhystridium sp., Poikilofusa squama (Deunff) Martin, Poikilofusa sp., Polygonium dentatum (Timofeev) Albani, Retisphaeridium brayense (Gardiner and Vanguestaine) Moczydlowska and Crimes, Saharidia fragilis (Downie) Combaz, Solisphaeridium akrochordum (Rasul) Moczydlowska and Stockfors, S. lucidum (Deunf) Turner, Timofeevia phosphoritica Vanguestaine, Timofeevia microretis Martin, Vulcanisphaera africana Deunff and V. turbata Martin. The assemblage provides elements to compare them to some early referred microfloras in northern Argentina, eastern Newfoundland, southwestern Sardinia, Algeria, north Spain, Baltica and Avalonia. All faunas are indicative of cold water affinities as expected from the western margin of Gondwana, showing some Baltic affinities as well.