The geotectonic story of the northwestern branch of the Caribbean Arc: implications from structural and geochronological data of Cuba (original) (raw)
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The Journal of Geology, 2011
SHRIMP and conventional zircon dating place temporal constraints on the evolution of the Cretaceous Volcanic Arc system in central Cuba. The arc has a consistent stratigraphy across strike, with the oldest and deepest rocks in the south (in tectonic contact with the ∼5-10-km-wide Mabujina Amphibolite Complex [MAC]) and younger rocks in the north. The MAC is thought to represent the deepest exposed section of the Cretaceous Volcanic Arc and its oceanic basement in Cuba. We undertook a single zircon geochronological study of five gneisses and two amphibolites from the MAC and seven rocks from the Manicaragua Batholith, which intrudes both the MAC and the Cretaceous Volcanic Arc. A SHRIMP zircon age of Ma for a trondhjemitic orthogneiss (MAC) from the Jicaya River 132.9 ע 1.4 dates the oldest phase of granitoid magmatism in this area and the entire Caribbean (Antillean) region. A tonalitic gneiss collected near the previous sample yielded an age of Ma, and a further tonalitic gneiss had an age 123.9 ע 0.6 of Ma, with one inherited zircon at Ma. Two trondhjemitic orthogneisses from the central part 112 ע 2.1 1045 ע 17 of the MAC yielded ages of and Ma, whereas two amphibolites from the eastern part of the 93.8 ע 0.5 92.8 ע 0.7 complex provided similar ages of ca. 93 Ma and zircon inheritance at 315, 471, 903, and 1059 Ma. Two weakly foliated Manicaragua granitoids from the eastern part of the massif provided ages of and Ma, whereas 89.3 ע 0.45 87.2 ע 1.2 five unfoliated granitoid samples from the central and eastern part of the massif yielded ages of , 88.7 ע 0.7 , , , and Ma. Our age data support the view that the Mabujina Protholiths 87.4 ע 1.3 87.0 ע 0.6 84.2 ע 0.8 83.1 ע 0.8 are exotic and formed somewhere NNW along strike of the nonmetamorphosed Cuban arc since pre-Middle Hauterivian time (before ∼133 Ma). The MAC became part of the Cuban Volcanic Arc during the Turonian (ca. 90-93 Ma), when it was intruded by plutonic rocks of the Manicaragua Batholith (Turonian-Campanian; ca. 89-83 Ma). The geology and geochronology of central Cuba do not support the idea of a polarity reversal event at any stage of the Cretaceous Arc-building process. Because most of our dated samples come from the narrow Mabujina Belt, the polarity reversal model would imply that the axis of a newly developing arc (with opposite polarity) would spatially coincide with the older arc, which appears unlikely. Inherited Precambrian and Palaeozoic zircons in the MAC granitic rocks (similar to inherited zircon populations in the Guerrero terrane from central-western Mexico) suggest a Neocomian proximal setting close to a cratonic area (probably SW Mexico/Maya Block) for the protolith of the MAC relative to the synchronous Primitive Island Arc of central Cuba.
… Society of America …, 1999
Accreted terranes, comprising a wide variety of Jurassic and Cretaceous igneous and sedimentary rocks, are an important and conspicuous feature of Cuban geology. Although the Mesozoic igneous rocks are generally poorly exposed and badly altered, we have collected and geochemically analyzed 25 samples that place new constraints on plate tectonic models of the Caribbean region. From our recognizance sampling, six main lava types have been identified within the Mesozoic igneous rocks of Cuba: rift basalts, oceanic tholeiites, backarc basin lavas, boninites, island arc tholeiites (IAT), and calc-alkaline lavas. We suggest that the rift-related basalts may have formed during the development of the proto-Caribbean, as the Yucatan block rifted away from northern South America in Jurassic-Early Cretaceous time. The Early Cretaceous oceanic tholeiites have flat rare earth element patterns, and are compositionally similar to Pacific mantle plume-derived oceanic plateaus of similar age. The Early Cretaceous arcrelated rocks are either backarc basalts, boninites, or relatively trace element-depleted IAT lavas. A limited amount of geochemical and field evidence hints that two parallel arc systems existed in the western proto-Caribbean area in Early Cretaceous time. This leads us to speculate that in the proto-Caribbean at this time there was a western arc with a northeast-dipping subduction zone erupting IAT lavas (with Farallon plate being consumed), and a more eastern boninitic arc with a south-west-dipping subduction zone (with proto-Caribbean plate being consumed). This latter arc was relatively short lived and after being aborted was mostly eroded away. The Cretaceous primitive (IAT) arc survived and, later in Cretaceous time, as this arc system moved into the widening gap between North and South Americas, calc-alkaline lavas began to be erupted. The evidence suggests that the change from IAT to calc-alkaline lavas was gradual and not abrupt. These new data, although limited, provide geochemical constraints on the tectonic development of the northern part of the Caribbean plate. In consequence, we present a new plate tectonic model for this area of the Caribbean.
Cuban Geology: A New Plate-Tectonic Synthesis
Journal of Petroleum Geology, 1994
Cuba is considered here to consist of two separate geological units: a foldbelt and a neoautochthon. The foldbelt can be subdivided into: (i) continental units, comprising Mesozoic Bahamian Platform and slope deposits, which are overlain by a Paleocene-Late Eocene foreland basin; and the Cuban SW terranes (Guaniguanico, Pinos and Escambray), which were probably originally attached to the Yucatan Platform; (ii) oceanic units, namely: the northern ophiolite belt; the Cretaceous (?Aptian Campanian) volcanic arc, which is overlain by a series of Latest Cretaceous-Late Eocene "piggy-back" basins; and the Paleocene-Middle Eocene volcanic arc which is overlain by a late-Middle-latest Eocene "piggy-back" basin. The neo-autochthon is composed of slightly-deformed, latest Eocene to Recent sedimentary rocks, which unconformably overlie the folded belt. A large number of tectonic models for the Caribbean area have been published in recent years, but rarely include modern data on the geology of Cuba. The Author here presents a plate-tectonic model for the western Caribbean which is based on the following premises: (i) opening of the Caribbean took place along several parallel rifts-zones, and a main transform fault located between the entrance of the Gulf of Mexico and the Demarara Plateau; (ii) the Cretaceous Greater Antilles volcanic arc faced the ProtoCaribbean Sea, and essentially northward-dipping subduction took place; and (iii) the western Caribbean Paleocene-Middle Eocene volcanic arc also faced the Caribbean Sea, with subduction dipping towards the NNW. Hydrocarbon production in Cuba comes from oilfields located in both continental and oceanic units. The Northern Oil Province coincides with the Bahamian platform and slope deposits and the Guaniguanico Terrain. The Southern Oil Province is represented by the latest Cretaceous-late Eocene sedimentary basins and the Cretaceous volcanic arc.
Cenozoic tectonic history of the North America-Caribbean plate boundary zone in western Cuba
Journal of Geophysical Research, 1997
Structural studies of well-dated Jurassic to lower Miocene rocks in western Cuba constrain the sequence of structural events affecting this oblique collisional zone between the late Cretaceous island arc and the Jurassic-Cretaceous North America passive margin in the southeastem Gulf of Mexico and Straits of Florida. Results of detailed mapping and collection of fault slip data at 34 sites define a regionally consistent, five phase tectonic model for the period from the late Paleocene to the post-early Miocene. During the late Paleocene to the early Eocene, the Cuban island arc collided with the North American passive margin (Bahamas Platform). Northwest-ward overthrusting during the collision defines tectonic phase I. A NNE-SSW compression concurrent with early Eocene left-lateral strike-slip faulting along the Pinar fault zone defines phase II. This result is consistent with structural mapping showing sinistral shear within the 065 ø striking Pinar fault zone. An ENE-WSW to E-W compression defining phase III overprinted phase II faults in the lower Eocene and older rocks. Post-early Miocene normal faulting characterizes phase IV. Inversion of fault slip data indicates two contemporaneous directions of tension of 120 and 170. Strike-slip faults that overprint phase IV normal faults yield a 120 compression (phase V). The direction of compression associated with the arc/continent collision rotates clockwise from NW-SE in the late Paleocene/early Eocene (phase I), to NNE-SSW (phase II) and to ENE-WSW by the middle Eocene (phase III). The rotation in the compression direction occurred because the arc turned toward an oceanic area in the present-day area of central and eastern Cuba. Progressive collision led to complete subduction of the remnant oceanic crust by middle to late Eocene time. Collision between arcs and continents leads to orogenesis and the reorientation of arcs toward a nearby oceanic margin or "free face" [McKenzie, 1972; Burke and Seng6r, 1986]. The Cenozoic collisional history of the Caribbean arc has been proposed as an example of the tectonic escape process. Northwestward movement of the Caribbean plate was opposed by the collision between the Caribbean plate and Bahamas Platform [Malfait and Dinkelman, 1972; Rosencrantz, 1990] (Figure lb) and yielded to Eocene to Recent east-northeastward motion in eastern Cuba, Hispaniola, and Puerto Rico [Mann et al., 1991, 1995] (Figure la). Transtensional left-lateral strikeslip faults beneath the Yucatan basin and in the Cayman Trough allowed continued clockwise rotation, collision, and eastward motion toward a free face in the Atlantic Ocean. The negative buoyancy of the subducted Jurassic-Cretaceous age Atlantic Ocean lithosphere [Royden, 1993] was probably the driving force for the change in plate convergence direction and continued motion of the Caribbean arc toward the free face to the east
Geochemistry of the Mabujina Complex, Central Cuba: Implications on the Cuban Cretaceous Arc Rocks
The Journal of Geology, 2003
The margins of the Caribbean plate are marked by Cretaceous island-arc basalts associated with accreted fragments of the Cretaceous Colombian Caribbean oceanic plateau. In Cuba, the Cretaceous volcanic island-arc rocks are in fault contact with the Mabujina complex, interpreted as an oceanic Jurassic to Early Cretaceous arc basement with local island-arc rocks. The Cuban Cretaceous island arc consists of Early to Late Cretaceous volcanic series associated with limestones. While the pre-Albian arc rocks consist of tholeiitic basalts and rhyolites, the post-Albian volcanic series is characterized by calc-alkaline andesites. The Cretaceous lavas have Sr and Nd isotopic compositions similar to the intraoceanic arcs, and the Pb isotopic initial ratios are close to the East Pacific Rise mid-ocean ridge basalt field. According to our data, the Mabujina arc rocks are tholeiites and calc-alkaline basalts, developed in a Jurassic and/or Early Cretaceous intraoceanic island arc. Their Nd, Sr, and Pb isotopic compositions indicate that they derive from a depleted mantle source contaminated by sediments. This subduction magmatism is not related to the classic Early Cretaceous Caribbean tholeiitic series but is similar to the Late Jurassic to Early Cretaceous Guerrero arc terrane from Mexico and may represent its southernmost extension. Thus, the different tectonic units of central Cuba cannot be easily correlated with those of Hispaniola. Our data also indicate that two different island arcs were tectonically juxtaposed in central Cuba: the classical Lower and Upper Cretaceous suites of the Greater Antilles arc and a Jurassic to Early Cretaceous island-arc suite with a Pacific provenance.
International Geology Review, 2008
Paleogene deposits of north-central Cuba have been identified as a deformed foredeep basin, whose stratigraphy recorded very well the collision of the Bahamas-Proto-Caribbean realm (North American plate) with the Caribbean plate, a process that occurred since latest Cretaceous to early Late Eocene time. The debris incorporated in the foredeep basin has two provenance regions and four tectonostratigraphic sources, including: (1) the Caribbean Plate (1a = allochthonous Cretaceous arcs, 1b = serpentinite mélanges and ophiolites); (2) the North American plate (2a = Pre-Paleogene sedimentary rocks derived from the substrate of the foredeep basin, 2b = Cretaceous Bahamian carbonate platform rocks). Evaluation of the age, size, and volume of the debris demonstrate the formation of a forebulge within the Bahamas platform in response to the collision between the Caribbean and North American plates, and the northeastward migration of the axis of maximum subsidence of the foredeep basin since the Paleocene. By the early Late Eocene, structural NE-SW shortening ended in central Cuba, with uplift and deep erosion, followed by a quick transgression before the end of the Eocene. The resulting Upper Eocene sediments unconformably cover the deformed foredeep deposits and underlying rocks, finishing the formation of the North Cuba-Bahamas fold-and-thrust belt. Palinspastic reconstructions suggest that this belt accommodated nearly 1000 kilometers of shortening, during underthrusting of the Proto-Caribbean crust below the Caribbean Plate.
The Journal of Geology, 2004
Ar/Ar ages determined on rocks and minerals from the Camagü ey area in central Cuba provide age constraints on events that accompanied the northward migration of Cuba into the Caribbean region and its subsequent collision with the Bahamas Bank. Whole-rock samples from the Camujiro and Piragua Formations, part of the Camagü ey volcanic sequence, yielded Ar/Ar ages of 74-72 Ma, distinctly younger than the 100-80-Ma ages indicated by fossils in interlayered sedimentary rocks. Syenite and granodiorite in the Camagü ey batholith, which cut these volcanic rocks, yield generally similar Ar/Ar ages of 75-72 Ma for hornblende, biotite, and feldspar. These ages are interpreted to reflect relatively rapid uplift and cooling of most of the volcanic-intrusive arc. Additional constraints on the timing of this uplift are provided by Ar/Ar ages of 71-75 Ma for rhyolite-rhyodacite domes of the La Sierra Formation and 52 Ma for andesitic basalt of La Mulata Formation, which appear to have been emplaced onto erosion surfaces that resulted from this uplift. An average cooling rate of about 13ЊC/Ma, which prevailed during formation of the arc between about 96 and 80 m.yr., increased to about 40ЊC/Ma after 80 Ma and ended with formation of a paleosurface at about 75 Ma or slightly afterward. The rapid uplift and denudation arc necessary to form a Late Cretaceous paleosurface on the volcanic-intrusive probably required an extensional tectonic environment, which could have been created during oblique convergence of the Greater Antilles arc with Yucatan as the arc migrated northward in Late Cretaceous time. Metamorphic rocks in the Escambray and Isle of Pines areas in western Cuba have ages similar to those indicated for uplift in the Camagü ey area, suggesting that extension and related Late Cretaceous paleosurfaces were widespread in the western Greater Antilles during its northward migration into the Caribbean region.
Journal of Metamorphic Geology, 2009
Petrological and geochronological data of six representative samples of exotic blocks of amphibolite and associated tonalite‐trondhjemite from the serpentinitic mélange of the Sierra del Convento (eastern Cuba) indicate counterclockwise P–T paths typical of material subducted in hot and young subduction zones. Peak conditions attained were ∼750 °C and 15 kbar, consistent with the generation of tonalitic partial melts observed in amphibolite. A tonalite boulder provides a U‐Pb zircon crystallization age of 112.8 ± 1.1 Ma, and Ar/Ar amphibole dating yielded two groups of cooling ages of 106–97 Ma (interpreted as cooling of metamorphic/magmatic pargasite) and 87–83 Ma (interpreted as growth/cooling of retrograde overprints). These geochronological data, in combination with other published data, allow the following history of subduction and exhumation to be established in the region: (i) a stage of hot subduction 120–115 Ma, developed upon onset of subduction; (ii) relatively fast near‐...
International Geology Review, 2016
The La Tinta mélange is a small but singular ultramafic mélange sheet that crops out in eastern Cuba. It is composed of dolerite-derived amphibolite blocks embedded in a serpentinite matrix. The amphibolite blocks have mid-ocean ridge basalt (MORB)-like composition showing little if any imprint of subduction zone component, similar to most forearc and MOR basalts worldwide. Relict Cr-spinel and olivine mineral chemistry of the serpentinized ultramafic matrix suggest a forearc position for these rocks. These characteristics, together with a hornblende 40 Ar/ 39 Ar age of 123.2 ± 2.2 Ma from one of the amphibolite blocks, suggest that the protoliths of the amphibolite blocks correspond to forearc basalt (FAB)-related rocks that formed during the earlier stage of subduction initiation of the Early Cretaceous Caribbean arc. We propose that the La Tinta amphibolites correspond to fragments of sills and dikes of hypoabyssal rocks formed in the earlier stages of a subduction initiation scenario in the Pacific realm (ca. 136 Ma). The forearc dolerite-derived amphibolites formed by partial melting of upwelling fertile asthenosphere at the beginning of subduction of the Proto-Caribbean (Atlantic) slab, with no interaction with slab-derived fluids/melts. This magmatic episode probably correlates with Early Cretaceous basic rocks described in Hispaniola (Gaspar Hernandez serpentinized peridotite-tectonite). The dikes and sills cooled and metamorphosed due to hydration at low pressure (ca. 3.8 kbar) and medium to high temperature (up to 720ºC) and reached ca. 500ºC at ca. 123 Ma. At this cooling stage, serpentinite formed after hydration of the ultramafic upper mantle. This process might have been favoured by faulting during extension of the forearc, indicating an early stage of dike and sill fragmentation and serpentinite mélanges formation; however, full development of the mélange likely took place during tectonic emplacement (obduction) onto the thrust belt of eastern Cuba during the latest Cretaceous.