Enrique Díaz-Martínez

Global biostratigraphic comparison and correlation of an early Cisuralian palynoflora from Bolivia

This paper presents new data about Early Permian (Cisuralian) strata, palynostratigraphy and absolute dating from the Copacabana Formation in central Bolivia. Recent stratigraphic and palynologic data from marine and transitional rocks at Apillapampa refine the age of Cisuralian palynomorphs in South America. Twelve samples interbedded with five volcanic ashes (processed and productive) yielded 94 palynomorph species arranged in two informal palynoassemblages: the lower assemblage Vittatina costabilis corresponds to one sample near the base of the Copacabana Formation and the upper Lueckisporites virkkiae assemblage occurs in overlying marine and coal-bearing transitional intervals. Ages were also independently refined by a modern review of conodonts, fusulinids, along with those U–Pb radiometric ages (Isotope Dilution Thermal Ionization Mass Spectrometry [ID-TIMS] of zircon-bearing interbedded tuffs). These data suggest that the lower marine member of the Copacabana Formation at this location is Asselian and Sakmarian. Lueckisporites virkkiae is a key species of palynomorph utilised in South American and global Permian biostratigraphic reconstructions. Hence, a thorough global comparison of these palynofloras and correlations is addressed in this contribution, considering first appearances of mainly cosmopolitan diagnostic taxa. Correlations are established with many similar Permian palynofloras, some also constrained with radiometric data, in South America (Brazil, Uruguay and Argentina) and elsewhere.

Estado actual de la legislación para la Geoconservación en España

Con el objetivo de poder disenar y llevar a cabo las actuaciones necesarias para garantizar la integridad del patrimonio geologico, el Departamento de Medio Ambiente y Vivienda de la Generalidad de Cataluna ha impulsado la redaccion de un estudio que identifica los impactos y las amenazas sobre los afloramientos del Inventario de Espacios de Interes Geologico de Cataluna asi como y propone las medidas convenientes para su conservacion y recuperacion.

Biostratigraphic Significance of Lower Cisuralian Palynoflora from Apillapampa, Bolivia

Recent stratigraphic and palynological data from marine and transitional rocks of the Copacabana Formation at Apillapampa in central Bolivia refine the age of Cisuralian palynomorphs in South America. Samples interbedded with volcanic ashes yielded palynomorph taxa arranged into two informal palynoassemblages: the lower assemblage Vittatina costabilis (Vc) occurs in one sample at the base of the Copacabana Formation, and the upper Lueckisporites virkkiae (Lv) assemblage is found in overlying marine and coal-bearing transitional intervals. Ages were also independently refined by a modern review of microfossil (conodonts and fusulinids) and five U–Pb radiometric ages (ID–TIMS of zircon-bearing interbedded tuffs), which confirm that the Copacabana Formation at this location is Asselian and Sakmarian in age. Lueckisporites virkkiae and other palynomorphs are key species of palynozones utilized in South American and global Permian biostratigraphic reconstructions. Hence, a thorough global comparison of these palynofloras and correlations is made in this study, considering the first appearances of mainly cosmopolitan diagnostic taxa. Correlations are established with many similar Permian palynofloras, some also constrained by radiometric data, in South America (Brazil, Uruguay, and Argentina) and elsewhere (Africa, Australia, Oman, and Saudi Arabia).