PALMARITO, Formation

UPPER PALEOZOIC (Pennsylvanian ? - Permian)

State of Mérida, Venezuela

Author of name: P. Christ, 1927.

Original reference: P. Christ, 1927, p. 402.

Original description: ibid.

The name "Palmarito series" was published by P. Christ in 1927 for a series of shales, marls and limestones, referred by him to the Carboniferous, which outcrop on the trail from Mucuchachí (State of Mérida) to Santa Bárbara de Barinas. The name is derived from the pass of Palmarito between two localities called Alto del Arenal and Palo Quemado. Christ's paper may have been the first mention (and certainly was the first full description) of upper Paleozoic beds in Venezuela. In the same year, Woodring (1927, p. 993) mentioned "Productus-bearing limestone float" collected by N. H. Darton from Río Araña, west of Calderas, in Barinas (then called Zamora); but as far as we know, no further details on that find were ever published.

Christ gave a fairly detailed description and measurements of the "Palmarito series", which he considered as Iying above his "Mucupatí series" (which in that place, corresponds to the Sabaneta formation of modern usage) and below his "Lomita series" (there equivalent to La Quinta). The "Palmarito series" was described as comprising the following beds, in descending order:

Upper Palmarito limestone-black limestone, 16 meters.

Productus clays-brown or yellowish marls, very fossiliferous, 20 meters.

Productus limestones-black fossiliferous limestones with marry intercalations, 18 meters.

Cephalopod limestone-hard limestone with badly preserved fossils, 9 meters.

Fusulina limestone- bluish-black fossiliferous limestone, 3 m.

Spirifer limestone- fossiliferous limestone alternating with marls, 24 meters.

Grey and greenish marls, 52 meters.

Trilobite marls- variegated fossiliferous marls, 25 meters.

Palmarito marls- grey or variegated marls, argillaceous, calcareous or somewhat sandy, partly fossiliferous 128 meters.

His description appears to have been very exact, since a more recent study of his type section (column given by González de Juana, 1951, fig. 7, p. 137, based on confidential information) differs from Christ's section mainly in a slightly more refined subdivision of the beds below the "Spirifer limestone". The total thickness is about 300 m. - Christ's paper was reviewed by Zimmermann (1928).

Christ discussed the fossils only in a very general way (mentioning Fenestella, Productus, euomphalid gastropods, nautiloids and fusulinids), stating that the collections had been sent to the museum at Basle, Switzerland. These collections were described by H. Gerth in 1931 (see Gerth and Krâusel. The undersigned has not seen this paper, and has found it cited in several different ways, but the citation by Thompson and Miller, 1949, síems to be the most complete). Gerth considered the fossils to indicate Carboniferous age, and discusses the Palmarito beds under that chapter in his "Geologic Südamerikas" (1932, p. 123) where he mentions several species.

Engleman (1935, p. 779) mentioned the Palmarito as "definitely Carboniferous" and showed it as present in various reconnaissance sections across the Andes (his fig. 4). He also mentions new fossil localities; one just above El Cobre on the Transandean highway, and two points south of La Grita. (These localities are erroneously referred to the Devonian by Bucher, 1952, p. 13). Schuchert (1935, p. 691) resumes information on the Palmarito to date, and agrees that it is Upper Carboniferous.

V. Oppenheim (1937, p. 36-38) also resumes earlier work, adding data on dips and strikes in Christ's section. and mentions plant remains in the lower part of the Palmarito (probably in what was later called by Kündig and Kehrer, the Sabaneta). Hedberg and Sass (1937, p. 79) mention "Fusulina-bearing beds of Carboniferous age" in the upper course of Río Palmar in Zulia, which appears to be the first notice printed of upper Paleozoic in the Sierra de Perijá.

In 1938, Kündig (p. 30) briefly mentions the "Palmarito group" which he states has a wide though scattered distribution in the Andes. He mentions as an equivalent, the "Batatuy group" (apparently the only published reference to this name), described as an unfossiliferous group of siliceous limestones with dykes and lenses of quartz porphyry found in the middle course of the Batatuy river, an affluent of the Suripá in southwest Barinas. Kündig also mentions "a group of sandy shales and sandstones with fossils typical of Upper Carboniferous and perhaps of Lower Permian" (he mentions Fenestella, Naticopsis, Orthothetes and Crenistria) described in an unpublished report by J. Krebs from Rio Cachirí. According to Liddle, however (1946, p. 130), Krebs' locality and fossils are Devonian.

Kehrer (1938, p. 52-54) discusses the Palmarito more fully, and gives an extensive list of fossils identified by J. Steele Williams. He considers that both Permian and Upper Carboniferous are represented in the formation, the latter only in the anticlines. He states that the Palmarito is underlain by older, plant-bearing sandstones and red shales, called the "Sabaneta group" (see SABANETA, Formation).

H. P. Schaub (1944, p. 1642-44) reported the occurrence of fusulinids in limestone blocks in a basal conglomerate of the La Quinta formation, this limestone presumably having been derived from the Palmarito. The schwagerinoid wall structure of the fusulinids was believed to indicate a possible age range from Middle Pennsylvanian to Permian.

Liddle (1946, p. 124-131) sums up most of the earlier publications on the Palmarito "series" and adds details on the occurrence of rocks in the Río Cachirí section, considered by him as correlative. He stated that probably only part of the Permo-Carboniferous, "probably only the Upper Permian" (sic) is represented. He described the beds as principally red micaceous shales or sandy shales with a basal conglomerate containing limestone fragments, (some 1,500 feet in all), but with 50-75 feet of blackish, redstained limestone in the top of the section, said to carry crinoid stems, Rhombopora (?) or Alveolites (?) and a Spirifer. González de Juana (1951, p. 134) suggests that only the upper limestone may correspond to the Palmarito, the red beds being Sabaneta; he uses the term "Palmarito group" in his cross-sections to include Sabaneta? -Palmarito formations, not differentiated. -The undersigned would suggest that perhaps these red beds are infaulted La Quinta (the basal conglomerate with limestone blocks sounds very like that.) -Liddle mentions red beds on the rivers Gé, Cogollo and Tinacoa as possibly Palmarito, possibly Triassic. He cites indirect evidence for the presence of Permo-Carboniferous in the mountain, not yet found in situ: float with Productus liddlei Harris found in the Cafio del Oeste branch of Río Cachirí; also the report of fusulinids from the upper course of Caño Pescado, a tributary of Río Palmar (cf. Hedberg and Sass, 1938).

Sutton (1946, p. 1636) discusses the Palmarito, its distribution and thickness, giving a figure of 1,800 meters in the type region. It should be noted, however, that Sutton apparently includes the Sabaneta in his Palmarito, since he does not mention it separately.

Thompson and Miller (1949) describe fusulinids and cephalopods from the Palmarito and equivalent beds on the Colombian side of the Sierra de Perijá.

González de Juana (1951, p. 134-136) gives an excellent resume of the Palmarito (called formation), with a columnar section, a geologic section of the region between Alto del Arenal and La Aguada (after an unpublished report by L. Kehrer), and notes on the distribution, recording its occurrence near Mérida. Following the usage of Kündig and Kehrer, he excludes the Sabaneta from the Palmarito, treating it as a separate formation. Sellier de Civrieux (1951) identified from the collections of González de Juana, a species of Globivalvulina close to G. graeca Reichel, a species characteristic of the upper Guadelupian stage.

With regard to the paleontology and age: considering that the Palmarito beds are described by all observers as highly fossiliferous, it is distressing that so little has been published on the fauna. The identifications of macrofossils (at least those by Gerth) date from a time when marine Carboniferous (Pennsylvanian) and Permian, in South America, were not clearly distinguished, and before the important Permian section in southern Perú and been recognized as such (see Dunbar and Newell, 1946; Newell, 1949). The most reliable information on the age of the Palmarito is the paper by Thompson and Miller (1949) on the fusulines, although they had only a limited number of samples available for study, (and some of the best, from the Colombian side of the frontier). These authors find that near Manaure (Colombia) the lowermost Permian (Wolfcampian) may be represented, in samples with Pseudoschwagerina dalmusi and perhaps Schwagerina? hedbergi; in the same region, the next higher stage (Leonardian) is definitely indicated by the ammonoid Perrinites hilli Smith (identified by Miller and Williams, 1945). Thompson and Miller believe that some large, highly developed forms of Parafusulina from the same area (P. nancei, P. trumpyi, P. durhami) may be Leonardian or lower Guadelupian in age. -In the Venezuelan collections, they found P. nancei in a sample of Palmarito limestone from the gorge of Río Boconó, below the town of Boconó. Pebbles of Palmarito from a basal conglomerate of the La Quinta formation, 15.5 km. from Ciudad Trujillo on the road to San Lázaro (probably Schaub's locality) yielded Stafella sp. and three species of Parafusulina not specifically identifiable, but rather primitive, the authors believe perhaps even older than Leonardian. At the other extreme, from other pebbles from a La Quinta basal conglomerate in the type Palmarito region, Thompson and Miller believe that a species called for convenience Parafusulina? sp. D., may actually be a Polydiexodina, a genus restricted in North America to the upper Guadelupian.

The evidence therefore definitely points to the possibility that, in one place or another, practically all the Permian (except possibly the uppermost Ochoan stage, not fossiliferous in the U. S.) may be represented within one continuous section. Changes in the configuration of the Permian seas might well have resulted in the formation of similar lithotopes at different times and different places. Carefully zoned collections and refined paleontologic studies will be necessary to clear up these questions.

Whether the Palmarito also includes Carboniferous, and if so, which stages, is another question which will have to await similar studies, since discrimination of Carboniferous and Permian on the basis of the non-fusulinid faunas is admittedly difficult. However, it may be recalled that as long ago as 1930, R. E. King (1930, p. 36) with remarkable insight, pointed out that the Amazonian Carboniferous fauna described by Derby (1894) contains definitely lower Pennsylvanian species, whereas the Peruvian-Bolivian "Upper Carboniferous", as it was then considered, has distinctive Permian forms such as Waagenoconcha. Since then, in addition to marine Permian, marine Pennsylvanian has definitely been identified in Perú (Dunbar and Newell, 1946; Kummel, 1948), and in Colombia (see Trumpy, 1943; Royo y Gómez, 1945); even marine Mississippian has been identified in Colombia (in the Surata and Gachalá formations, see Royo y Gómez). Moreover, we cannot dismiss the fact that earlier workers did believe that Carboniferous is represented in the fauna, and that some of the named species (e.g. Chonetes amazonicus) suggest relations with the Amazonian fauna.

The writer, therefore, would not be at all surprised if future studies should show, either that there is a continuous sequence of Pennsylvanian-Permian within the Palmarito, or (we think more probable) that there is an unsuspected hiatus within the formation, with Pennsylvanian and Permian separated by a considerable time-interval. The change from a predominantly shaly-marly lithotope in the lower part of the formation, to a predominantly limestone one in the upper part, is perhaps suggestive. The necessity for precise geographic and stratigraphic localization of fossil collections cannot be overstressed.

Distribution. -On the geologic-tectonic map of Venezuela compiled by Dr. Bucher, only a few areas of "Permo-carboniferous" are shown (1950); this map is admittedly very generalized as regards the Andes. (According to Bucher, 1952, p. 13, the Sabaneta is mapped with the "Devonian", so that the symbol "PC" should refer only to the restricted Palmarito). Bucher observes that the outcrops appear to be related to the structure of the overlying Mesozoic beds (Bucher, 1952, p. 14-15). The presence of Palmarito on the upper part of the Boconó river (Bucher's map, south part of quadrangle D:9-10) is paleontologically confirmed. It is also shown as present in the Cerro Azul uplift (see article on the Cerro Azul). Though none is mapped near Trujillo, Bucher admits it probably occurs near that city (1952, note 6, p. 15); González de Juana reports it as occurring on the highway between Timotes and La Puerta. The largest area mapped is in the region of Christ's type section. (Possibly this includes some Sabaneta: since there is said to be a fault between Cretaceous and Sabaneta in this region). A small area is mapped near Pregonero (near SW corner, C-8 of Bucher's map); another isolated area near Chachopo (NW corner D-8); two others, one south of El Cobre near Queniquea, another near La Grita. González de Juana (1951) reports exposures near Mérida (not shown on Bucher's map). In the Serrania de Perijá, various small areas are indicated, but the formation might well have a more extensive distribution in the heart of the range, than yet recognized. Sutton (1946, p. 1636) suggests that redbeds on Toas Island belong to the Palmarito, but from the Ethology, we would refer these rather to the Sabaneta (if they are not indeed La Quinta).

In the type region, the Palmarito is said to overlie the Sabaneta with transitional contact. However, Schürmann (1939, p. 25, fide Bucher) reports that at El Cobre, "Permo-Carbonirerous limestones" lie unconformably on strongly folded, red and green fossiliferous shales (age?). The Palmarito is overlain by the La Quinta, frequently with a basal conglomerate composed of fragments of Palmarito limestone, which suggests perhaps a post-Palmarito orogeny.

Frances de Rivero

SABANETA, Formation

PALEOZOIC (Devonian? - Lower Carboniferous ?)

State of Mérida, Venezuela

Author of name: Unknown.

Original references: E. Kündig, 1938, p. 28; L. Kehrer, 1938, p. 53.

Original description: ibid.

The name "Sabaneta group", for Paleozoic beds, was published simultaneously in 1938 by two geologists of the Caribbean Petroleum Co., E. Kündig and L. Kehrer. The reference by Kündig has page priority, but on the other hand, the locality mentioned is not what has subsequently been stated to be the type locality; Kehrer's description apparently does refer to the type. Since both geologists were associated with the same company, and Kehrer was the senior geologist, is seems convenient to consider the two as joint authors.

The type locality (not specified in the original references, but given on Kehrer's authority by González de Juana, 1951) is Sabaneta in southeastern Mérida (Distrito Libertad). This is in the region of the section across the Andes from Mucuchací to Santa Bárbara de Barinas, published by Christ (1927); the reader is referred to the article on the "Sabaneta group" of Oppenheim (1937) for the background of previous work and general geology, necessary to understand what is left unsaid in the original references to the Paleozoic Sabaneta. As we stated there, the "Mucupatí group" of Christ included both beds stratigraphically below the Permocarboniferous Palmarito "group", and much younger Cretaceous beds in fault contact with the pre-Palmarito. This fault is shown on Kehrer's geologic map of the southern Andes (1938), but since (1) the Palmarito and the Paleozoic Sabaneta are not differentiated on the map; (2) Christ's confusion with the Mucupatí is not brought out, and finally (3) neither Kündig nor Kehrer makes any reference to the paper by Oppenheim (1937) and his use of the "Sabaneta" for Cretaceous beds, their discussions are somewhat unsatisfactory.

Kündig, for instance, introduces the term "Sabaneta" in a section headed "Mucupatí group: Middle to Upper Devonian". After some inconclusive remarks about the Mucupatí, including that Kehrer thinks it might be Cretaceous, Kündig goes on to say:

. . . "In the highway from Páramo de Zumbador to Queniquea, in a highly disturbed region, there outcrops, possibly below the Carboniferous Palmarito group, a group of quartzitic sandstones, extremely hard and thickbedded, of greenish to reddish color (called unofficially the Sabaneta group) which has been considered as upper Devonian or Lower Carboniferous. They show no signs of metamorphism, and the contact with the overlying Carboniferous seems to be, as far as can be seen, transitional." (Kündig, 1938, p. 29).

Kehrer introduces the term after a description of the Palmarito "group"; the fact that he mentions that a good section of the Palmarito is exposed between Palmarito and Sabaneta, and that the description of the Sabaneta immediately follows that of the Palmarito, is the only indication that the name "Sabaneta" is derived from this region:

"Below the fossiliferous shales and limestones of Permian and Upper Carboniferous age . . . there appears a body of hard sandstones and shales of reddish or greenish color, the Sabaneta group which in places greatly resembles the red beds of the La Quinta (Gir¢n) formation. However, their position is undoubtedly below the Palmarito limestone. Plant remains are very frequent. Possibly they may be compared with the Pipital" (misspelled Piripital in the Spanish text) "beds which occur below the Carboniferous in the Quetame massif between Bogotá and Villavicencio, in Colombia. Their age is not known with certainty, but it is assumed that they could represent Lower Carboniferous" (Kehrer, 1938, p. 53-54).

These descriptions were quoted by Liddle (1946, p. 124-125) under the general heading of "Palmarito series". Liddle incorrectly refers to the Sabaneta "series". Sutton (1946, p. 1646) mentions Oppenheim's Cretaceous Sabaneta, but not the Paleozoic formation of Kündig and Kehrer, which we presume is included in his Palmarito.

The ambiguities and deficiencies of the original descriptions were remedied to a considerable extent by González de Juana (1951), who had access to a private report by Kehrer. The following data, therefore, taken from González de Juana's paper, may be taken to represent Kehrer's understanding of the Sabaneta.

The type locality of the Sabaneta (called "formation" by González de Juana, instead of the incorrect original designation of "group") is, as mentioned above, specified as being Sabaneta, some 3 kilometers southeast of La Aguada, and a geological section showing the relations of the La Quinta, Palmarito and Sabaneta formations is included (González de Juana, 1951, fig. 5). The Sabaneta is described as consisting of sandstones and sandy shales, frequently micaceous, of reddish and greenish colors, with some conglomeratic intervals, lithologically similar to the La Quinta beds but distinguished by somewhat darker red color tending to wine-red, by the slaty character of the shales, and by the different origin of the components of the conglomerates. Reddish colors are said to predominate in the upper part of the formation, while towards the base there are deeper tints and greenish shades. The thickness is between 500 and 600 meters. The Sabaneta is said to lie on the metamorphic rocks of the Mucuchachi, with an apparently transitional contact, and to be transitional above with the Palmarito formation.

In addition to the type region, and the exposures already mentioned by Kündig (Zumbador-Queniquea in Táchira), the Sabaneta is reported to occur on both sides of the La Negra pass; on the road from Timotes to La Puerta (Trujillo), where it contains some thin coal beds with plant fossils; on the road from La Cuchilla to Carache, and in the "alto" of Bolivia. In addition, since the Mérida formation of Kundig (1938) is said to have been proved exactly equivalent to the Sabaneta, the latter must be said to outcrop near the city of Mérida. On the east front of the Perijá range, Liddle (1946) does not mention it, but González de Juana considers that the lower, red part of Liddle's "Palmarito" on Río Cachirí, should be referred to the Sabaneta. (riddle's mention of a basal conglomerate with limestone pebbles, suggests to the undersigned that these beds might be La Quinta, but Liddle lays stress on the absence of fusulinids in this limestone, so that the correlation with the Sabaneta may be justified.)

Bucher (1952, p. 13) calls the Sabaneta "Late Devonian or early Mississippian" and states that in his geologic-tectonic map of Venezuela, it has been included under the symbol for Devonian (De). (However, in the type region, the area he maps as "Permo-Carboniferous" presumably includes the Sabaneta.)

Nothing has been published about fossils from the Sabaneta. González de Juana (1951, p. 133) reports having collected some gastropods from the formation, on the highway between Timotes and La Puerta, but there is no information available. The only grounds for deducing the age are, the stratigraphic position, and the reported frequency of plant remains, which in itself suggests that the formation is not likely to be older than, say, upper Devonian. As regards the reported transitional relations with the Mucuchachí (itself of undetermined age, Cambro-Ordovician in the opinion of Sutton, Devonian according to Kehrer and González de Juana) and with the Palmarito above, the undersigned frankly doubts that both (if indeed either) of these contacts have been adequately investigated. Considering the highly disturbed nature of the region, the contact with the Mucuchachí might be difficult to determine or interpret; while as regards the supposed transition with the Palmarito, there is some evidence to the contrary. Christ (1927) himself thought that there was an angular discordance of about 15ø between the Palmarito and his "Mucupatí" (in that place, Sabaneta) in the vicinity of Palo Quemado. He states (we quote without page reference, since the paper is available to us only in a private translation):

..."150 or 200 meters N. W. of the house "(Palo Quemado)" there are sandy clays of a reddish or brownish color, the dip of which is about 45°NW, while the Trilobite clays "(Palmarito)" dipped only about 20 to 25°".

Bucher (1952, p. 15) also quotes Schürmann (1939, p. 25) to the effect that near El Cobre, Permo-Carboniferous limestones lie unconformably on strongly folded, red and green unfossiliferous shales. Bucher suggests that this unconformity may indicate a "Variscan", pre-Permocarboniferous orogeny.

Without going so far as to consider this definitely proved, we would remark that the lower age-limit of the Palmarito has not yet been determined, and we believe (as mentioned in our article on the Palmarito) that the formation may be of different ages in different places. Reworking of earlier red continental beds by a transgressing Palmarito sea, might give rise to an apparent transitional contact. On the other hand, it is possible that the contact really is transitional (at least in places), which would mean that the Sabaneta might be somewhat younger than generally supposed (Pennsylvanian or even early Permian). -Or again, it is possible that red formations of more than one age have been included in the Sabaneta, (i. e. the beds at El Cobre may be older than the type Sabaneta at Sabaneta. ) What seems to us definitely not probable, is that one formation could represent all the interval from perhaps Pennsylvanian down to upper Devonian or perhaps even older (depending on the age of the Mucuchachí). The solution of these problems will have to be left to future researches. Study of the Sabaneta fossils could be the first step of their solution.

Frances de Rivero