MERIDA, "Series"

See MERIDA, Formation.

MERIDA, Formation

PALEOZOIC (Lower Carboniferous ?)

State of Mérida, Venezuela

Synonym of SABANETA, Formation.

Author of name: E. Kündig, 1938.

Original reference: E. Kündig, 1938, p. 24.

Original description: ibid.

The term "Formación de Mérida" (in the English edition: Mérida "series") was proposed by Kündig (1938, p. 24) for beds exposed in the Quebrada de la Virgen, on the right bank of the Albarregas river, west of the city of Mérida; this was stated to be the type locality. The formation was described as consisting of semi-metamorphic slates and shales, thin-bedded, red and light grey in color, alternating with beds of light-gray pyritic argillite and thin lenses of dark-grey to black limestones, locally highly silicified. The beds are said to be highly folded. The thickness is estimated between 500 and 1,000 meters. Other localities given are: north of San Juan (not otherwise localized); northwest of Estanques; between La Grita and Bailadores; and in the north flank of the Hato ridge.

Kündig considered that the Mérida formation represented the upper part of the Mucuchachí formation, which he assigned to the "Eopaleozoic". This opinion was also expressed by Kehrer (1938, p. 54) who assigned the Mucuchachí tentatively to the Devonian; Kehrer, however, observes that "in some cases it appears difficult to distinguish the red Mérida formation from the red Sabaneta or La Quinta (Girón) formations". Liddle (1946, p. 122) discusses the Mérida together with the Mucuchachí as Devonian.

González de Juana (1951, p. 134), who had access to information from Kehrer, states that subsequent studies have shown that the Mérida formation is exactly equivalent to the Sabaneta formation of Kündig (1938) and Kehrer (1938), although slightly less metamorphoséd. Ee adds details on the lithlogy of the Mérida formation as exposed in the highway from Egido to Mesa de los Indios, near Mérida. Here the formation consists of conglomeratic sandstones and fine-grained conglomerates, of greenish colors, intercalated with lustrous, slightly sericitic phyllites with flecks of muscovite. Graphite is locally present, and thick bands of wine-red color appear in some horizons. The grade of metamorphism in this section is very low.

No fossils have been reported from the Mérida; for discussion of age, see article on the Sabaneta.

Although the Sabaneta and the Mérida are considered synonymous, the undersigned suggests that it might be convenient to provisionally retain both names, until such time as the Paleozoic formations of the Andes shall be really adequately studied and described, when the one with the best type section could be selected. In case the Palmarito and the Sabaneta-Mérida should be shown to be as intimately associated as has been suggested, one of the names (Sabaneta or Mérida) might be raised to group status, thus avoiding the inconvenience of using Palmarito both as a formation and as a group name (as used by González de Juana, 1951, fig. 10, for undifferentiated Palmarito-Sabaneta? in Río Cacirí).

Frances de Rivero