Guillermo F. ACEÑOLAZA1)

1 INSUGEO – Facultad de Ciencias Naturales e I.M.L., Universidad Nacional de Tucumán, Miguel Lillo 205, 4000 Tucumán. E-mail: insugeo@unt.edu.ar

Palabras clave: Estratigrafía. Bioestratigrafía. Cambro-Ordovícico. Pintayoc. Jujuy. Argentina.

Twenty five km northwestwards of Humahuaca town, the locality of Pintayoc display a thick succession of whitish-yellowish sandstones and shales bounded by submeridional faults (Fig. 1).

The strata has been assigned mostly to the lower sector of the Santa Victoria Group, represented by equivalents levels to the Casa Colorada, Alfarcito and Rupasca formations (Aceñolaza, 1996a).

At this locality we will see some indian paintings on tops of some sandstone levels of the lowermost sector of the Santa Victoria Group.

Stop 1 – Pintayoc

(Upper Cambrian-Tremadocian Santa Rosita Formation)

Sandstones, quartzites and shales characterize the stratigraphy at this locality. This 250 meter section display minor repetition on its shalier interval (Fig. 2).

Large rhabdosomes of Rhabdinopora flabelliformis highlight in this locality (Aceñolaza, 1996b) (Fig. 3).

Trilobites of the Parabolina (N.) frequens argentina biozone are represented all along the stratigraphical sequence: Parabolina (N.) frequens argentina, Parabolinella argentinensis, Beltella ulrichi, "Shumardia" erquensis, Angelina hyeronimi, Plicatolina scalpta, Triarthrus tetragonalis and Protopeltura mesembria are mentioned among frequent fossils. Echinoderms assigned to the genus Macrocystella were also described in the sequence (Aceñolaza, 1996a).

Aceñolaza, G.F., 1996. Bioestratigrafía del límite Cámbrico-Ordovícico y Ordovícico basal en la Quebrada de Humahuaca, Provincia de Jujuy, República Argentina. Unpublished Doctoral Thesis, Facultad de Ciencias Naturales e IML, National University of Tucumán, 245 p.

Aceñolaza, G.F., 1996b. Presencia de Rhabdinopora (Graptolithina) en la Quebrada de Humahuaca, provincia de Jujuy. Ameghiniana, 33 (1): 111-128.