SABANETA, "Group"

CRETACEOUS

State of Mérida, Venezuela

Author of name: unknown.

Original reference: V. Oppenheim, 1937, p. 41-43.

Original description: ibid.

The name "Sabaneta group" was proposed by V. Oppenheim (1937, p. 41-43) for beds exposed on the southeast flank of the Venezuelan Andes, in the region first described by P. Christ in 1927. The "group" was described as consisting of yellow sandstones and schists, with abundant plant fossils; the age was given as Cretaceous.

In view of the fact that the following year, the name "Sabaneta group" was used by Kündig (1938) and Kehrer (1938) for beds in the same general region, but which were stated by Kehrer to directly underlie the PermoCarboniferous Palmarito beds, it seems advisable to sketch here some of the geological and historical background.

According to the geologic-tectonic map of Venezuela compiled by Bucher (1950), the trail from Mucuchachí (in Mérida) to Santa Bárbara (in Barinas) cuts across a region of complex structure, with several major faults, of which the ones pertinent to our discussion are: a great thrust fault with NE-SW trend which, a little north of Sabaneta, brings a wide belt of Cretaceous into contact with "Permo-carboniferous". Another parallel fault, further south, cuts off the Cretaceous, bringing Ordivician and older beds (the Caparo and Bellavista formations) up against the Cretaceous.

Christ (1927) not recognizing these faults, interpreted the structure along the trail as essentially a simple descending stratigraphic succession. The part of this succession that we are concerned with, was correlated by him as follows (the modern names being given in parenthesis):

Lomita series, lower Cretaceous or perhaps lower and middle Mesozoic, even Permian, transgressive over all older beds. (La Quinta formation, Mesozoic, pre-Cretaceous.)

Palmarito series, Carboniferous. (Permian and probably Carboniferous.)

Mucupatí series, Devonian. (Now known to include both pre-Palmar, to terrestrial beds, i.e. Sabaneta of Kündig and Kehrer, plus Cretaceous.)

Caparro-Bellavista series, older Paleozoic.

The reader is here referred to a geologic section by Kehrer (published by González de Juana, 1951, fig. 5), which shows part of the geology along the trail. Unfortunately, this section does not extend far enough to the southeast to show the fault-contact with the Cretaceous. As far as the region covered by Kehrer's section goes, Christ was essentially correct in his interpretation of a descending succession. Unfortunately, however, not recognizing the fault, he considered his "Mucupatí" to extend all the way to the Caparo river, thus including a considerable section of Cretaceous beds of sandy facies similar to the partly red, sandy and conglomeratic beds below the Palmarito (Kündig and Kehrer's Sabaneta). By 1937, when Oppenheim visited the region, Cretaceous fossils had been found in that part of the "Mucupatí", which introduced obvious difficulties in the interpretation of the section. Oppenheim states that one of the principal points he wished to clear up, was whether Devonian actually was present.

Unfortunately, Oppenheim's interpretation of the structure and sucession contains such a singular combination of egregious errors and brilliant successes that it is difficult to judge it impartially. He correlated the red beds helow the Palmarito (in the region around Corral, see Kehrer's section as above cited) with Christ's "Lomita series", i.e. the much younger La Quinta; in order to do this, the contacts near Corral had to be interpreted as faults. On the credit side, he did recognize that there was a change in Ethology within Christ's "Mucupatí" southeast of La Aguada, and stated that it was caused by a fault or faults. Unfortunately, the absence of a detailed map of the region (plus the fact that Oppenheim's figures for altitudes, which he uses to localize the contacts, differ widely from the figures shown in Kehrer's section) make it impossible for one unfamiliar with the region to tell whether the Cretaceous contact is correctly located. Thus, where Oppenheim refers to the Cretaceous Sabaneta, beds which occur at an altitude of 280 meters in the Quebrada Sabaneta (not otherwise localized), it seems reasonably certain that these beds are Cretaceous; but whether these are correlative with the "yellow sandy schists with abundant plant fossils" which he says are in fault contact with the "Lomita" at an altitude of 820 meters (300 meters lower in altitude than La Aguada, distance not specified), the undersigned is unable to judge. The critical point is precisely here, since according to González de Juana (1951, p. 133), who had access to Kehrer's data, the type locality of Kehrer's Paleozoic Sabaneta is some 3 kilometers southeast of La Aguada. To make matters worse, the Paleozoic Sabaneta is also described as containing abundant plant remains. (On the other hand, the fossils that Kehrer cites as proving the Cretaceous age of part of the Mucupatí are marine. Kehrer, 1938, p. 51.)

The writer is therefore unable to judge, whether Oppenheim's "Sabaneta group" coincides in part with Kehrer's Paleozoic Sabaneta, or whether it is entirely Cretaceous. Fortunately, however, the point is rather academic, as is the fact that both Sabaneta are homonyms of Garner's (1926) Sabaneta limestone (Tertiary of Falcón). Garner's name has fallen into disuse. Oppenheim's Sabaneta, as a name for Cretaceous in the region of southeast Mérida, has been supplanted by the much better described Aguardiente formation (Sutton, 1946, p. 1646). This leaves geologists free to use the name Sabaneta for the Paleozoic beds, as described by Kündig and Kehrer, and to credit the name to these authors, since Oppenheim, without specifying a type section, made it perfectly clear that he intended the same Sabaneta to refer to the Cretaceous.

Frances de Rivero