MARAVAL, Beds

JURASSIC ?

Island of Trinidad, B. W. I.

Author of name: H. H. Suter, 1951.

Original reference: H. H. Suter, 1951, p. 189.

Original description: H. H. Suter, p. 190.

H. H. Suter (1951, p. 189-190) describes the Maraval beds, the type-area of which includes the sites of Cameron, Maraval and Aripo (Trinidad), as a 70,000 ft. (2,135 m.) thick sequence overlying the Maracas beds. Such sequence begins with phyllites similar to those of the Maracas beds and contains "several layers of epi-zone marbles and recrystallised limestones", which assume locally considerable thicknesses. "The upper boundary is transitional to the Laventille limestone complex". Suter mentions the occurrence of the ammonite Perisphinctes transitorius Zittel, found by Hutchison (1938-39) in a thin limestone layer of the Maracas beds, at the Cuare dam. According to Spath (cit. by Suter), other ammonites found near Cumana, east of Cuare, are of Tithonian-Neocomian age.

Kugler (1953, p. 30) indicates that small lenses of gypsum are occasionally exposed in road cuttings made on the Maraval beds, to the north of Port-of-Spain. Farther to the east, and in the same strike, the old St. Joseph mine has 10 m. of massive, banded gypsum with some crystals of pure sulphur. Those lenses, originally mentioned by Wall and Sawkins (1860), had been subsequently included by Suter (1951, p. 191), in the overlying Laventille formation.

According to Kugler, the Maraval beds outcrop in the islands of Dragon's Mouth and the high hills of the western part of the Northern Range of Trinidad. The same author correlates the Maraval beds with part of the outcrops from eastern Paria Península, and specially with a facies exposed at Cristóbal Colón (Macuro) and Morrocoy, where "quarries are opened in massive banded gypsum of about 25 m. thickness with an intercalation of 3 m. of "Rauwacke".

The occurrence of gypsum is considered by Kugler "of importance in any future correlation of the Caribbean Series of Venezuela and Trinidad" for it undoubtedly indicates a semi-arid land condition in pre-Cretaceous time. Kugler indicates that in the Cristóbal Colón and morrocoy facies, "gypsum is probably lenticular and normally bedded between silvery and red weathering, satiny, sericitic phyllites rich in graphitoids and with lenses and layers of silty, blue-gray, crystalline limestone".

Based on paleogeographic considerations, Kugler (ibid.) established a relation between: 1) the gypsiferous facies of Macuro (or Cristóbal Colón) correlated with the Maraval beds, 2) the dense argillites facies, pink sandstones and quartzitic conglomerates of the Carrizal-Hato Viejo formation located farther south, and 3) the conglomerate facies and sandstones of Roraima located even farther to the south.

Kugler, basing himself on Imlay's ideas, believes that a Callovian age for the gypsum deposits of the Gulf of Paria, is possible. He indicates that such hypothesis depends on the accurate age determination of the overlying Laventille formation.

The Maraval beds, outcropping in the northen part of Trinidad, constitute a broad belt oriented east-west. It is limited in its northern part by the Maracas beds and by Pleistocene sediments in the south.

The equivalents of the Maraval beds in the State of Sucre (Venezuela) might be included in the so-called "Araya-Paria metamorphic group". González de Juana (1947, p. 694) considers it of Jurassic or perhaps older age.

J. M. Sellier de Civrieux