Resumo

ROSALES-TORRES, Sara et al. Pliocene-Pleistocene Palynoflora recovered from the Villa Alegría and Cierro Prieta travertines in the Tehuacán-Cuicatlán Valley, Mexico. Rev. mex. cienc. geol [online]. 2017, vol.34, n.2, pp.114-137. ISSN 2007-2902.

Using standard methods, the Pliocene-Pleistocene paleopalynological assemblages recovered from both the Villa Alegría lacustrine sediments in northern Tehuacán-Cuicatlán Valley (TCV) and the Cerro Prieto travertine in the southern portion of the TCV exhibited high taxa diversity. Clear groupings of floristic elements were observed in cluster and multivariate principal components analysis (PCA), suggesting that during the Pliocene-Pleistocene the regional vegetation comprised cloud forest (possibly containing undergrowth rich in Cyatheaceae), pine-oak forest, gallery forest, mexical and tropical deciduous forest. For the Pleistocene, paleopalynological assemblages recovered from the Cerro Prieto travertine suggest that climatic conditions were slightly colder and more humid. The distribution of vegetation harbored by the TCV followed an altitudinal moisture gradient caused by the topography. Based on previous geological studies, the sedimentation environment inferred for Villa Alegría lacustrine sediments was a lake saturated in calcium carbonate sourced from the Sierra Mazateca, while that of the Cerro Prieto travertine was a flood zone in which carbonate-saturated waters from the Zapotitlán Formation accumulated. Based on biozone abundance, strong correlation between Villa Alegría lacustrine sediments and the Cerro Prieto travertine was observed.

Palavras-chave : palaeofloristic reconstruction; pollen; travertine; lacustrine sediments; Pliocene-Pleistocene; Tehuacán-Cuicatlán Valley; Mexico.

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