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Jurassic paleogeography and biogeography of west-central Pangaea: Some preliminary notes. Section 1 Plate Tectonics: Pre break-up fit of western Pangaea and the early opening of the Caribbean M. Iturralde-Vinent
Section 1 Plate Tectonics: Pre break-up fit of western Pangaea and the early opening of the Caribbean
Section 2 Stratigraphy of the Circum-Caribbean Realm and the Gulf of Mexico M. Iturralde-Vinent
Section 3 Biogeography of the Jurassic Marine Animals M. Iturralde-Vinent and Zulma Gasparini
Pre break-up fit of western
Pangaea and the early opening
of the Caribbean
The following slides provide some geological data about the Cuban Southwestern Terrains, the North Cuban belts, and the age of the ocean crust, useful to understand the early opening of the Caribbean.
terrains (CSW) and the North Cuba allochthonous belts
(Ophiolites and Placetas belts)
PROTO CARIBBEAN CRUST AND MARGINS
Jurasic marine basalts found in Siquisique (Bajocian), Guaniguanico terrain (Oxfordian) and Camaján (Tthonian) are indications of extension of the continental margin and the coeval formation of oceanic crust within the Caribbean (Iturralde-Vinent, 1988, 1994, 1998).
in the Gulf of Mexico
The age of the ocean crust in the Gulf of Mexico has been identified as Late Jurassic Oxfordian (Sawyer et al., 1991; Marton and Buffler, 1999), post-dating the evaporite beds deposited in the area.
Dating the Caribbean crust is a complicated matter, as it is considered allochthonous by many authors (Pindell, 1994). Consequently, the occurrence of Jurassic radiolarian cherts associated with basalts in Dominican Republic (Late Jurassic), Puerto Rico (Pliensbachian, Kimmeridgian-Tithonian) and La Desirade (Tithonian) (Montgomery et al., 1994) is currently interpreted as a probe of the allochthony of the Caribbean crust, because these antique crustal elements “pre-date” the opening of the Caribbean (Pindell 1994).
Therefore, the safest way to identify the age of the original ocean crust in the Caribbean would be the occurrence of marine basalts intercalated within the continental margin sections of the area.
Marine basalts are known from Bajocian-Bathonian age (Andean terrains: Siquisique, Venezuela), Oxfordian-early Kimmeridgian age (Guaniguanico terrain, Cuba), and early Tithonian age (Camaján hills, North Cuban foldbelts). As Siquisique may be part of the Pacific ocean crust, the 400 m thick Oxfordian-early Kimmeridgian basalts in Guaniguanico are the oldest best indication of the possible occurrence of in situ oceanic crust in the Caribbean (Iturralde-Vinent, 1988, 1994). This also suggests that oceanic crustal formation may have started somewhat earlier.
1. The pre break-up fit of Pangaea must be kept loose in order to open a space between Maya Block (Yucatan) and South America (SOAM) for the Cuban Southwestern terrains.
2. The presence of marine basalts within the continental margin sections of NOAM and SOAM suggest that the Caribbean may have been partially opened since the Bathonian-Bajocian, but certainly since the Oxfordian.