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

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

Geologica Acta

Instituto Jaume Almera - CSIC -

Lugar: Barcelona; Año: 2007

1695-6133

The first Cambro-Ordovician 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 (N.) frequens argentina trilobite biozone, is composed by Acanthodiacroidium cf. angustum (Downie) Combaz, Actinotodisus sp., Cristallinium cambriense (Slaviková) Vanguestaine, Cymatiogalea velifera (Downie) Martín, C. virgulta Martin, C. aspergillum Martin, Dasydiacroidium caudatum Vanguestaine, Dasydiacroidium sp., Eliasum llanicum Fombella, Impluviculus multiangularis (Umnova) Volkova, Izhoria angulata Golub y Volkova, Ladogella rommelaerei (Martín) Di Milia, Ribecai y Tongiorgi, Ladogella sp., Leiofusa sp., Lophosphaeridium sp., Poikilofusa squama (Deunff) Martin, Saharidia fragilis (Downie) Combaz, Timofeevia phosphoritica Vanguestaine, Timofeevia cf. microretis Martín, Vulcanisphaera africana Deunff. The association provides elements to compare them to some early referred faunas in northern Argentina, Algeria, and Morocco. All faunas are indicative of cold water affinities as expected fro the western margin of Gondwana, showing some Baltic affinities as well.