Transcript iturralde_guatemala_0201

WESTERN-CARIBBEAN
Tectonic Deformations as
Recorded in the Cuban Foldbelt
ITURRALDE-VINENT, Manuel A.
Museo Nacional de Historia Natural, Obispo no. 61,
Plaza de Armas, La Habana 10100 Cuba,
[email protected]
Many tectonic elements which today built-up
the Cuban foldbelt, originally where part of the
Mesozoic North American passive margins
and the Proto-Caribbean and Caribbean crusts.
They are represented by the Bahamian-North
Cuban foldbelt, the Cuban Southwestern
Terranes and the Northern Ophiolites.
The North American continental margin units
crops out along the northern half of the island (Bahamian
borderland) and as the Cuban Southwestern terranes
(Mayan borderland).
85°W
84°W
83°W
82°W
81°W
80°W
79°W
78°W
77°W
76°W
75°W
74°W
La Habana
Matan zas
23°N
23°N
Guaniguanico
terrane
Pina r del Rio
Sa nta Cla ra
Cienfue gos
22°N
22°N
Pinos
terrane
Nue va Ger ona
Tr inidad
Cubitas
Escambray
terrane
Cama guey
Camaján
Gibara
Bahamian
Bahamianmargin
borderland
21°N
21°N
Holguin
Yucatán
margin
Mayan (Yucatan)
borderland
Asunción
terrane
Santiago de Cuba
20°N
0
85°W
100
84°W
20°N
200KM
83°W
82°W
81°W
80°W
79°W
78°W
77°W
76°W
75°W
74°W
85°W
84°W
83°W
82°W
81°W
80°W
79°W
78°W
77°W
76°W
75°W
74°W
La Habana
Matan zas
23°N
23°N
Guaniguanico
terrane
Pina r del Rio
Sa nta Cla ra
Cienfue gos
22°N
22°N
Pinos
terrane
Nue va Ger ona
Tr inidad
Cubitas
Escambray
terrane
Cama guey
Camaján
Gibara
Bahamian margin
21°N
21°N
Holguin
Yucatán margin
Asunción
terrane
Santiago de Cuba
20°N
0
85°W
100
84°W
20°N
200KM
83°W
82°W
81°W
80°W
79°W
78°W
77°W
In the 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 (Paleocene-Eocene).
76°W
75°W
74°W
La Habana
Matan zas
23°N
23°N
Guaniguanico
terrane
Pina r del Rio
Sa nta Cla ra
Cienfue gos
22°N
22°N
Pinos
terrane
Nue va Ger ona
Tr inidad
Cubitas
Escambray
terrane
Cama guey
Camaján
Gibara
Bahamian margin
21°N
21°N
Holguin
Yucatán margin
Asunción
terrane
Santiago de Cuba
20°N
0
85°W
100
84°W
20°N
200KM
83°W
82°W
81°W
80°W
79°W
78°W
77°W
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
their tectonic deformations and metamorphism.
76°W
75°W
74°W
85°W
84°W
83°W
82°W
81°W
80°W
79°W
78°W
77°W
76°W
75°W
74°W
La Habana
Matan zas
23°N
23°N
Guaniguanico
terrane
Pina r del Rio
Sa nta Cla ra
Cienfue gos
22°N
22°N
Pinos
terrane
Nue va Ger ona
Tr inidad
Cubitas
Escambray
terrane
Cama guey
Camaján
Gibara
Bahamian margin
21°N
21°N
Holguin
Yucatán margin
Asunción
terrane
Santiago de Cuba
20°N
0
85°W
100
84°W
20°N
200KM
83°W
82°W
81°W
80°W
79°W
78°W
77°W
76°W
75°W
In the Guaniguanico terrane there is no record of
Mesozoic tectonic deformation or regional
metamorphism. Deformation took place during
Paleocene and early Middle Eocene.
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.
74°W
Age of the deformations in the
continental margin areas
The deformations of the North American continental margin
took place in progression from Cretaceous to Late Eocene.
85°W
84°W
83°W
82°W
81°W
80°W
79°W
78°W
77°W
76°W
75°W
74°W
La Habana
Matanz as
23°N
23°N
Guaniguanico
terrane
Pinar del Rio
100
0
San ta Clar a
200 KM
Cienfueg os
22°N
22°N
Pinos
terrane
Nuev a Gero na
Tr in id ad
Cubitas
Escambray
terrane
Camag uey
Gibara
Cretaceous
21°N
21°N
Holguin
Paleocene-Middle Eocene
Middle to Upper Eocene
20°N
85°W
Asunción
terrane
84°W
83°W
82°W
81°W
Santiago de Cuba
80°W
79°W
78°W
77°W
76°W
20°N
75°W
74°W
POSSIBLE RESTORED POSITION OF THE CUBAN TERRAINS
BAHAMAS
Bahamas
Gulf of Mexico
Guaniguanico
Pinos
Yucatán
Escambray
Caribbean
South America
The deformations along the components of the
Cuban Foldbelt have some important implications:
It has been proposed that these deformations record the
interaction between the North American Plate (NOAM) and the
Caribbean Plate (CARIB). If this is so, them:
1. The oldest deformations are recorded in the Pinos and
Escambray terranes, suggesting that they were the first to interact
with CARIB.
2. The youngest deformations are identified along the
Guaniguanico terrane and the Bahamian borderland, recording
the so called CARIB “collision” with the Bahamas.
Cuban ophiolites
Within the Northern Cuban Ophiolites occur inclusions of
HP/LT metamorphic rocks, including metasedimentary ones,
whose K-Ar age range from 126±9.6 - 67 ±10.4 Ma.
85°W
84°W
83°W
N
82°W
81°W
80°W
79°W
78°W
77°W
76°W
75°W
74°W
La Habana
Matanz as
23°N
Guaniguanico
terrane
23°N
K-Vo
lcanic
Pinar del Rio
arc
San ta Clar a
Cienfueg os
Deformations
within the
Volcanic Arcs
0
Caba ig uan
22°N
Pinos terrane
Flor id a
Camag uey
Cretaceous arcs
Paleogene arcc
K-Volcanic arc
Bahamian borderland
21°N
Victor ia d e la s Tuna s
Holguin
Northern Ophiolites
P
Volcanic arc (K-Cretaceous, P-Paleogene)
20°N
85°W
22°N
Ciego de Avila
Tr in id ad
Escambray terrane
21°N
K
200 KM
100
Nuev a Gero na
P-Volcanic arcSantiago de Cuba
Guan ta namo
20°N
Yucatán borderland
84°W
83°W
82°W
81°W
80°W
79°W
78°W
77°W
76°W
Within the sections of the volcanic arcs can be recorded a
number of regional deformational events. These deformations
took place during the Aptian, Coniacian-Santonian, late
Campanian, Maastrichtian-Paleocene and Middle Eocene.
Every deformation is associated with local hiata,
conglomerates, changes in the geochemistry of the magmas,
and with plutonite emplacement -sometimes of very large
scale, as during the latest Cretaceous and the Middle-Late
Eocene.
75°W
74°W
The deformations within the Northern Ophiolites and
the Volcanic Arcs have additional implications:
1. Is quite probably that these deformations record intraplate
tectonic events of the Caribbean (CARIB) and Proto-Caribbean
Plates (P-CARIB).
2. The fact that P-CARIB elements (Northern ophiolites)
suffered deformations since the Early Cretaceous, suggest that
this plate had had a rather complicate history.
3. The punctuated deformations recorded within the volcanic arcs
since the Aptian, imply that the Arc terranes were deformed way
before the “collision” with the Bahamas, also probably due to
intraplate events.
Cenozoic paleogeographic
evolution of the Caribbean
Late Cretaceous paleogeography of the western Caribbean
25Þ
Florida Platform
Bahamas Platform
Cretaceous deformation
and metamorphism
Chix ulub
20Þ
Yucatan Platform
NORTHERN
OPHIOLITES
Cuban Platform
ESCAMBRAY
TERRANE
?
PINOS
TERRANE
15Þ
Jamaica
Paleocene paleogeography of the western Caribbean
25Þ
Florida Platform
Bahamas Platform
FORELAND BASINS
Chixulub
20Þ
Yucatan Platform
Yucatan
Deep
ARC
PIGGYBACK BASIN
15Þ
-90Þ
-85Þ
-80Þ
-75Þ
Eocene deformation of the western Caribbean
Progressive deformation
of the continental margin
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 along the Bahamian borderland
took place from West to East, and embrace only the
Paleocene-Late Eocene.
3. The deformations of the Northern Ophiolites took
place from South to North, and lasted since the
Cretaceous and until the Late Eocene.
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.
Pr oject 433
Ca r i bbea n P la t e
This is a contribution to
IGCP Project 433:
"Caribbean Plate Tectonics"