MARACAS, Beds

JURASSIC ?

Island of Trinidad, B. W. I.

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

Original reference: H. H. Suter, 1951, p. 190.

Original description: ibid.

The Maracas beds were named by H. H. Suter (1951, p. 190) to designate a section in the northern coast of Trinidad, with which the pre-Cretaceous (Jurassic) of the Caribbean "series" begins. A typical sequence outcrops "along the Maracas road". It consists of "gray to black sericitic-chloritic, red weathering phyllites with intercalated layers of grits, followed by a zone of some 1,500 ft. of fine-grained, homogenous, dense epiquartzites, overlain by a sequence of phyllites". The sediments of this group are lightly metamorphosed. A total thickness of ? 22.000 ft. (6.700 m.) is indicated by Suter (p. 189) for the Maracas beds. Such thickness is reduced by Kugler (1953, p. 33) to 3.300 m.

Kugler (p. 28), based on the fact that the rocks constituting the Northern Range of Trinidad show a regional dip to the east, searched westward for older rocks. In the eastern end of the Paria Península, State of Sucre, Venezuela, he found an augen-gneiss unit, which he called Dragón formation. This formation, which does not seem to outcrop in Trinidad, is considered by Kugler as probably underlying the Maracas beds, and basal part of the Caribbean series.

Kugler did not get to see the contact between the Dragón formation and the rocks that would be definitely equivalent to the Maracas beds. Nevertheless, he indicates having collected pebbles at Cristóbal Colón (State of Sucre), in a river with its head water "in the high mountains west of the gneiss outcrop". Judging from these pebbles, greenish, well-bedded quartz-mica schists must be overlying the Dragón formation. They are comparable with the "epi-quartzites" of the Maracas beds. Kugler is of the opinion that such post-Dragón outcrops of the Caribbean Series, between Punta de las Pefias and Cristóbal Colón, with a thickness of at least 3000 m., have a consistent S-SE dip, along the width of the Paria Península. The lower part of this section could well be correlated with the Maracas beds. while the facies containing gypsum, rich in overlying graphitoids, that outcrop at Cristóbal Colón and Morrocoy, would represent an equivalent of the Maraval beds.

The Maracas beds have an extensive distribution in northern Trinidad, where they constitute a E-W extending band between the Toco beds, located to the NE, and the Maraval beds, located to the south (Suter, 1951, Geologic Map, front p. 214).

In the State of Sucre the metamorphic complex (undifferentiated) has been called "Araya-Paria metamorphic group" by González de Juana (1947, p. 694) and assigned to Jurassic or perhaps older age.

Kugler assigns to the Maracas beds, the overlying Maraval beds and the Laventille formation, a Jurassic age.

J. M. Sellier de Civrieux