Abstract

MARTINEZ, Marcelo A.; QUATTROCCHIO, Mirta E.  and  PRAMPARO, Mercedes B.. Palynological analysis of the Los Molles Formation, Cuyo Group, Middle Jurassic of the Neuquén Basin, Argentina. Ameghiniana [online]. 2005, vol.42, n.1, pp.67-92. ISSN 1851-8044.

Sporomorphs and paleomicroplankton identified from the Middle Jurassic, Los Molles Formation, Cuyo Group, are described and illustrated in this contribution. The palynomorphs were recovered from three of the five sampled surface sections (Lohan Mahuida, Puente Picún Leufú, Puesto Policía, Los Molles and Cerro Lotena) located near Zapala city, Neuquén Basin, Argentina. The studied microfloras include 50 species of sporomorphs (20 spores and 30 pollen grains) and 31 species of paleomicroplankton (9 green algae, two dinoflagellate cysts and 20 acritarchs). Specimens belonging to the genera Divisisporites , Callialasporites , Monosulcites and one spore gen. et sp. indet. are described. Systematics include prasinophyte of the genera Cymatiosphaera , Pleurozonaria and Tasmanites . Also included are acritarchs of the genera Baltisphaeridium , Filisphaeridium , Micrhystridium , Leiosphaeridia , Polygonium and Veryhachium . The new combination Cymatiosphaera volkheimerii (Quattrocchio) is proposed. The occurrence of the acritarchs Filisphaeridium balmei (Sarjeant) Sarjeant and Stancliffe, F. castaninum (Valensi) Sarjeant and Stancliffe, F . densispinum (Valensi) Sarjeant and Stancliffe and Veryhachium valensii (Valensi) Downie and Sarjeant is mentioned for the first time in the Neuquén Basin. The studied palynofloras are correlated with the Biozone of Callialasporites "complex" (Sub-biozone of Callialasporites trilobatus (Balme) Dev, Antulsporites saevus (Balme) Archangelsky and Gamerro and Klukisporites labiatus (Volkheimer) Baldoni and Archangelsky) previously proposed for this area of the Neuquén Basin. A Late Aalenian - Early Bajocian age is suggested for the studied sections.

Keywords : Palynology; Systematics; Los Molles Formation; Middle Jurassic; Neuquén Basin; Argentina.