Permian palynostratigraphy of the Claromecó Basin, Argentina

Abstract

The first palynozonation for Permian strata of the Claromecó Basin (Argentina) is formally proposed, based on palynological assemblages recovered from the UTAL.CMM1 La Estrella.x-1 and UTAL.CMM1 Cruz de Sur.x-1 boreholes, drilled on the Argentinian Continental Platform and correlation with established zones from neighbouring basins. Fifty-five samples were analyzed and 131 species identified from two biozones. The lower Converrucosisporites confluens–Vittatina vittifera (CV) Zone occurs in the Piedra Azul and Bonete formations of both boreholes. This zone can be assigned a Cisuralian–Guadalupian age. The upper Tornopollenites toreutos–Reduviasporonites chalastus (TC) Zone registered in the Tunas Formation can be assigned a Guadalupian–Lopingian age. The CV Zone is dominated by diverse non-taeniate bisaccate, plicate and taeniate pollen. Monosaccate and monosulcate pollen, algae and acritarchs are poorly represented in both biozones. The composition of the TC Zone is broadly similar to the CV Zone, but bisaccate pollen grains are markedly more diverse and abundant in the former.

基于从阿根廷陆台的UTAL.CMM1 La Estrella.x-1和UTAL.CMM1 Cruz de Sur.x-1钻孔采得的孢粉组合，以及与相邻盆地已建立的孢粉带的对比,本文正式提出Claromecó盆地（阿根廷）二叠系地层的第一个孢粉带划分。我们对五十五个样本进行了分析，鉴定了两个生物带的131种。较低的Converrucosisporites confluens–Vittatina vittifera (CV)出现于两个钻孔的Piedra Azul 组和Bonete组。此带的年代可定为Cisuralian–Guadalupian。上部Tunas组中的 Tornopollenites toreutos– Reduviasporonites chalastus (TC)带的年代可定为Guadalupian– Lopingian。CV带以各种非带形两气囊类、扇形和带形花粉为主。 单气囊形和单槽形花粉、藻类和疑源类在两个生物带中代表性不足。TC带的组成与CV带大致相同，但前者两气囊形花粉颗粒明显更加多样和丰富。

Key words:

• palynostratigraphy
• Permian
• Claromecó Basin
• Argentina.

Acknowledgements

The author thanks S. Archangelsky for allowing access to palynological samples, P. Gutiérrez for important suggestions during my PhD thesis work and development of this paper and C. Sylwan for helpful information. Special thanks to B. Cariglino, L. Palazzesi, the editor S. McLoughlin, and the reviewers C. Foster and E. Schneebeli-Hermann for valuable comments and suggestions that helped greatly improve the manuscript. This research was funded by Agencia Nacional de Promoción Científica y Técnica (research grants PICT No. 32693 and CONICET PRESTAMO BID PICT 2010 No. 2196).