TEMEMURE, Group

TERTIARY (prevailing upper Eocene)

State of Guárico, Venezuela

Author of name: J. Evanoff, 1951.

Original reference: J. Evanoff, 1951, p. 245.

Original description: J. Evanoff, 1951, p. 245-246.

The name Tememure group, was first used by Evanoff (1951, p. 245). Although the author assigns to this group a predominant upper Elocene age, it is possible that part of the beds are older. It was named from the Tememure Creek, in the neighborhood of the village of San Rafael de Orituco. The formation outcrops upstream of the Tememure Creek, where the establishment of a provisional type section was attempted, but an entirely satisfactory determination was impossible there. Due to difficulties in obtaining a differentiation between lateral variations of the facies, the unit has been considered as a group.

Shales and sandstones with some limestone lenses, are the component rocks of this group. The shales are arenaceous, gray, dark gray and black colored; their lamination is not as pronounced as in the Paleocene and Cretaceous shales. They are not as hard and are more brittle. The intercalated sandstones are light gray and buff, generally fine-grained, very compact and hard; locally white and friable, very similar to the Batatal formation. The limestones form small lenses and are similar to the limestones of the morros de Macaira, but its fauna is definitely upper Eocene. All the beds of the group are locally very glauconitic. The thickness of the individual beds is very variable, reaching a maximum of more than 5 mts.

The unit is generally very crushed and deformed and therefore its thickness is difficult to measure. It has been possible to measure a section of 900 mts., in the upper part of the Tememure Creek, to the northeast of San Rafael de Orituco. The group extends along the foothills in the States of Guarico, Aragua and Miranda, but the outcrops disappear to the west of Taguay, up to a point located to the west of Camatagua.

Upper Eocene orbitoid and nummulitic foraminifera have been described by Sellier de Civrieux (1951, p. 262-264), when studying the limestone lenses of the group, in particular, in reef masses located to the northeast of Altagracia de Orituco and to the southwest of San Francisco de Macaira. This microfauna contains: Discocyclina (Asterocyclina) asterisca (Guppy); Lepidocyclina (Pliolepidina) pustulosa (H. Douvillé); Operculinoides kugleri (Vaughan y Cole); Operculinoides sp. aff. trinitatensis (Nuttall). Small foraminifera, calcareous algae, mollusks and echinoderms are also frequent. Among the mollusk fauna, Glycymeris caracoli ?, Cypracorbis sp., Lithophysema sp., Pachycrommium sp., Turritella sp.

The Tememure group is (at least in part), equivalent to the Tinajitas formation of the Merecure group of northeastern Venezuela. The reef limestones of the region between Piritu and the mouth of the Unare River, named by Liddle (1946, p. 337) "El Picacho" and "Pehas Blancas horizons" represent also lateral equivalents of the Tememure group.

J. Evanoff