PHANEROZOIC TECTONIC EVOLUTION OF THE NORTH AMERICAN PLATE BOUNDARY IN CUBA

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PHANEROZOIC TECTONIC EVOLUTION OF THE NORTH
AMERICAN PLATE BOUNDARY IN CUBA

• ITURRALDE-VINENT, Manuel A.
• Museo Nacional de Historia Natural, Obispo no.
  61, Plaza de Armas, La Habana 10100 Cuba,
  iturralde_at_mnhnc.inf.cu

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Some stratigraphic sections which today occur in
the Cuban foldbelt, originally where part of the
Mesozoic North American passive margins and the
Proto-Caribbean crust.
They are represented by the Bahamian-North Cuban
foldbelt and the Cuban Southwestern Terranes.
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Outcrops of the North American continental
margin units along the northern half of the
island (Bahamian borderland) and as the Cuban
Southwestern terranes (Mayan borderland).
Bahamian borderland
Mayan (Yucatan) borderland
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Original position of the Cuban Southwestern
Terranes
Guaniguanico
Pinos
Escambray
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The Ophiolites and Volcanic Arc suites are in
tectonic position above the sections of the
Bahamian and Yucatan borderlands
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The evolutionary history of the North American
continental margin in Cuba can be subdivided
into three tectonic stages 1. Early Jurassic to
Latest Cretaceous 2. Latest Cretaceous to Late
Eocene 3. Latest Eocene to Recent
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Jurassic to latest Cretaceous
This stage is represented by siliciclastic and
carbonate rock sections that characterize the
formation and early evolution of the Caribbean
sea and its northern continental margin. This was
a stage of extensional stress and evolution from
intracontinental to open marine facies.
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Guaniguanico Terrane Mesozoic stratigraphy
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The Mesozoic stratigraphy of both the
Guaniguanico and Escambray terranes are very
similar, but the Pinos terrane differ in
representing a more continental-ward set of
siliciclastic and carbonate rocks.
An important distinction in the Mesozoic
geological history of these terranes is the age
of the tectonic deformations and metamorphism.
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In the stratigraphic sections of the Guaniguanico
terrane there is no record of Mesozoic tectonic
deformation or regional metamorphism.
The Escambray and Pinos terranes suffered
deformation and metamorphism during the
Cretaceous. K-Ar datings in these terranes record
thermal events at the end of the Cretaceous
(Pinos 78 - 65 Ma Escambray 85 - 65 Ma). Ar-Ar
and U-Pb dating record ages around 100 Ma.
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Stratigraphy of the Bahamian borderland and
Proto-Caribbean
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In the stratigraphic sections of the Bahamian
borderland there is no record of Mesozoic
tectonic deformation or regional metamorphism.
Deformation and very low degree of metamorphism
took place only during the Early Tertiary.
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Cuban ophiolites
Within the Northern Cuban Ophiolites occur
inclusions of HP/LT metamorphic rocks, including
metasedimentary ones, whose K-Ar age range from
1269.6 - 67 10.4 Ma.
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Paleocene to latest Eocene
This stage was one of collisional tectonics,
represented in the foreland sediments by a large
input of exogenic materials (elements derived
from the ophiolite and volcanic arcs). During
this stage took place the collision of
allochthonous units --oceanic crust and volcanic
arc-- with the continental margin. The Cuban
foldbelt was created.
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Paleocene-Eocene North American continental
margin foreland basins
The rocks in the foreland basins are strongly
deformed
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Guaniguanico terrane Stratigraphy of the
Paleogene Foreland basin
In the Guaniguanico terrane the deformations
started late in the Paleocene during the
deposition of the Manacas olistostrome which
yield abundant allochthonous debris from the
ophiolites and less amounts from the volcanic arc
Allochthonous debris
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Bahamian borderland. The oldest exogenic debris
(grains reworked from the ophiolites and
volcanic arcs) are found only in the Tertiary
sediments.
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Age of the deformations in the continental margin
The deformations of the North American
continental margin took place in progression from
Cretaceous to Late Eocene.
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Latest Eocene to Recent stage
The evolution of the North American continental
margin since the latest Eocene is characterized
by mild deformations generally along the trend of
wrench faults. In general represent
post-collisional tectonics associated with
transpresional and transtensional stress.
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Paleogeographic evolution of the continental
margins
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Late Cretaceous paleogeography of the continental
margin
Cretaceous deformation and metamorphism
NORTHERN OPHIOLITES
ESCAMBRAY TERRANE
PINOS TERRANE
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Paleocene-Eocene deformation of the continental
margin and the formation of the Cuban foldbelt
Progressive deformation of the continental margin
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CONCLUSIONS
1. The deformations along the borderland of the
Maya block took place from SW to NE, starting in
the Cretaceous (Pinos and Escambray terranes)
and lasted until the Middle Eocene (Guaniguanico
terrane).
2. The deformations of the Northern Ophiolites
took place from South to North, and lasted since
the Cretaceous and until the Late Eocene.
3. The deformations along the Bahamian borderland
took place from West to East, and embrace only
the Paleocene-Late Eocene.
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4. These facts corroborate the Plate Tectonic
models which require that the present Caribbean
Plate originated West of Pangaea, to became
intercalated between North and South America
since the Cretaceous.
5. Nevertheless, the same results also represent
a problem for the most common Caribbean models,
because none of them explain why the Bahamian
borderland is deformed only during the Paleogene,
while the ophiolites for a long period of time
since the Early Cretaceous.
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This is a contribution to IGCP Project 433
"Caribbean Plate Tectonics"