the metallogenic evolution of the greater antilles

X CONGRESO CUBANO DE GEOLOGÍA (GEOLOGIA´2013)
Conferencias Especiales
CESP-CE1
THE METALLOGENIC EVOLUTION OF THE GREATER ANTILLES
Carl E. Nelson (¹), Joaquín A. Proenza (²), J.F. Lewis (3), Jesús López-Kramer (4)
(1) Consulting Geologist, 2360 23rd St., Boulder, Colorado 80304 USA. (2) Departament de Cristal.lografia,
Mineralogia i Dipòsits Minerals. Facultat de Geologia, Universitat de Barcelona. Martí i Franquès, s/n, 08028
Barcelona, Spain. (3) Department of Earth and Environmental Sciences, The George Washington University,
Washington, D.C. 20052, U.S.A. (4) Departamento de Geología Ambiental, Geofísica y Riesgos. Instituto de
Geofísica y Astronomía. AMA-CITMA. Calle 212 /29 y 31, No 2906. La Lisa, Rpto La Coronela, Cuba.
Email: [email protected]; [email protected]; [email protected]; [email protected]
The Greater Antilles host some of the world’s most important deposits of bauxite and lateritic nickel as well as
significant resources of gold and silver, copper, zinc, manganese, cobalt and chromium. Beginning in Jurassic
time, sedimentary exhalative base metal deposits accumulated in marine sedimentary rift basins as North and
South America drifted apart. With the onset of intraoceanicsubduction during the Early Cretaceous, a primitive
(tholeiitic) island arc formed above a southwesterly-dipping subduction zone. Podiform chromite deposits formed
in the mantle portion of the supra-subduction zone, directly above subducted Proto-Caribbean oceanic
lithosphere. Within the nascent island arc, bimodal-mafic volcanogenic massive sulfide (VMS) deposits formed in
a fore-arc setting; mafic VMS deposits formed later in mature back-arc basins. The Pueblo Viejo gold district,
with five million ounces in production and twenty million ounces in mineable reserves, formed at 108-112 Ma, in
an apical rift or back-arc setting. By Late Cretaceous time, calc-alkaline volcanism was well established along
the entire length of the Greater Antilles. Volcanogenic massive sulfide and shallow submarine VMS deposits
characteristic of the primitive island arc gave way to porphyry copper and epithermal precious metal deposits
typical of the mature island arc. Oblique collision of the Greater Antilles with North America began in the Late
Cretaceous in Cuba and migrated eastward. Orogenic gold and tungsten deposits that formed during the
collision event are preserved in ophiolites and in metamorphic core complexes. Since the Eocene, regional
tectonism has been dominated by strike-slip motion as the North American continent pushes westward relative
to the Caribbean Plate. Large deposits of lateritic nickel-cobalt formed during Eocene and younger weathering
and supergene enrichment of ultramafic rocks. Bauxite deposits formed by mobilization and precipitation of
aluminium derived from volcanic intervals within a carbonate platform of Eocene to Miocene age.
V CONVENCIÓN CUBANA DE CIENCIAS DE LA TIERRA, GEOCIENCIAS´2013.
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X CONGRESO CUBANO DE GEOLOGÍA (GEOLOGIA´2013)
Conferencias Especiales
CESP-CE2
140 MILLION YEARS OF SUBDUCTION AND TERRANE COLLISION AND ACCRETION
IN THE LEADING EDGE OF THE CARIBBEAN PLATE (WITH EMPHASIS IN CUBA). A
METAMORPHIC PERSPECTIVE
Antonio García Casco
Departamento de Mineralogía y Petrología, Universidad de Granada, España; Associate Researcher, Dept. of
Earth and Planetary Sciences, American Museum of Natural History, NY, USA. Email: [email protected]
The long-lasting evolution of the trailing edge of the Caribbean plate constitutes a fascinating story dominated by
ocean (Protocaribbean) - ocean+arc (Caribbean) - continent (North and South America) convergence and
collision. This evolution, which is still ongoing, can be traced back (at least) to the early Cretaceous and affects
plate-boundary regions that conform a complex orogenic belt that extends from Guatemala through the whole
Antillean region, northern South America to the Andean region of Colombia and Ecuador. As shown by the
geologic record (e.g., volcanic arc, mafic-ultramafic complexes, metamorphic complexes), and as expected for
such an old and long belt of 140 Myr in age and ca. 6000 km in length, respectively, the geodynamic history of
the plate margin is complex, involving various types of plate boundary, lithosphere, and kinematic regime. During
the early stages of convergence in the early Cretaceous, much of the interactions involved oceanic lithospheres
with varied age and thermal state, while arc-continent interaction starting in the latest Cretaceous characterized
the Tertiary. In both stages, however, dynamic subduction zones dominated the scenario. The number,
geometry and age of these subduction zones are debated.
In this talk I shall review the geologic evidence for subduction and collision provided by high- and intermediatepressure metamorphic complexes of the trailing edged of the Caribbean plate (with particular emphasis in Cuba).
I shall offer an integrated analysis of subduction, collision and accretion in the region derived from the analysis of
thermal evolution rocks formed at depth since the onset of convergence in the plate boundary region. The main
goal is not to evaluate geodynamic modes, but to provide first-order constraints for their construction.
Many metamorphic complexes document subduction of oceanic lithosphere during the early Cretaceous - early
Tertiary. Much of this material is consistent with persistent SE-dipping oceanic subduction of the protoCaribbean below the Caribbean (Pacific) plate, until subduction of platform-derived sedimentary piles (e.g., SW
Maya margin, Caribeana, Bahamas, northern South America) took place during the latest Cretaceous-Tertiary.
However, metamorphic terranes also indicate that this evolving scenario from steady oceanic subduction to
platform subduction and arc-continent collision was not that simple. These complexes, generally "isolated",
document a number of intraoceanic interactions (collisions) that make any general geodynamic model for the
region to be plagued of uncertainties. Thus, the earliest stages are obscure. Judging from oceanic and arcderived high pressure rocks of Guatemala, west-central Cuba and Hispaniola, the earliest geodynamic scenario
entails two subduction zones (i.e., Pacific and proto-Caribbean) of opposite dip or one evolving subduction zone
with strong lateral component and a change of sense of dip along-strike. Also, intermediate- and high-pressure
metamorphism of volcanic arc sequences, both in the northern (Antillean) and southern (northern South
America) branches of the plate margin indicate complexities in the geodynamic scenario during the mid- and
late-Cretaceous. The high-pressure arc complexes document subduction of upper-plate volcanic arc material
that can be conceptualized in a framework of more than one subduction zone (and, correspondingly, more than
one arc). However, there is no need to appeal for complex arc-arc (±continent) interactions (subduction-collisionaccretion) and the problem can be resolved by means of subduction erosion of the Caribbean forearc-arc region
with or without a strong strike-slip tectonics. The intermediate-pressure volcanic arc-derived terranes, however,
document episodic events of mid-late Cretaceous intraoceanic collisions of two different arcs (or fragments of
one arc) in the Antillean region and the Tertiary collision between the Caribbean arc and northern South America
(when, as a result, subduction of the Caribbean plate below northern South America started). Scarce
metamorphic soles in the Antillean sector, with development of intermediate-P meta-MORB complexes below
the ophiolitic slices, reveal late Cretaceous onset of obduction of oceanic lithosphere. At this stage, arc-continent
collision is not recorded, and the simplest explanation for onset of obduction implies the development of nascent
subduction zones in the Caribbean back-arc region. In conclusion, metamorphic complexes do not support a
simple picture of steady oceanic subduction during the Cretaceous followed by latest Cretaceous Tertiary
subduction/collision of the continental margins of N and S America. Instead, unveils a dynamic scenario with
changing (in time and space) plate boundary geometries, similar to that of present-day western Pacific arcs.
V CONVENCIÓN CUBANA DE CIENCIAS DE LA TIERRA, GEOCIENCIAS´2013.
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X CONGRESO CUBANO DE GEOLOGÍA (GEOLOGIA´2013)
Conferencias Especiales
V CONVENCIÓN CUBANA DE CIENCIAS DE LA TIERRA, GEOCIENCIAS´2013.
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CESP-CE2
X CONGRESO CUBANO DE GEOLOGÍA (GEOLOGIA´2013)
Conferencias Especiales
CESP-CE3
MAGMATIC AND SEISMIC EVIDENCE FOR CONTINENTAL LITHOSPHERIC EVOLUTION
OF THE ANDEAN MARGIN UNDER THE SOUTHERN CENTRAL VOLCANIC ZONE ARC
AND PUNA PLATEAU (25°-28°S LATITUDE)
Suzanne Mahlburg Kay(1), Beatriz Coira
SeismicTeam(1, 3, 4)
(2)
, Ben Heit(3), Eric Sandvol(4), Puna
1. Dept of Earth and Atmospheric Sciences, Cornell University, Ithaca, NY, USA;2. CONICET, Casilla de Correo
258, (4600) San Salvador de Jujuy, Argentina; 3. GeoForschZentrum, Telegrafenberg, D-14473 Potsdam,
Germany; 4.Dept. Geol. Sci., University of Missouri, Columbia, MO 65211, USA.
The Central Andean margin has been proposed as a site of crustal destruction by forearc subduction erosion
and delamination (or foundering) of thick dense continental crust as well as an area of crustal addition and
reworking by arc magmatic processes. These destruction processes are supported both by the magmatic record
and by newly processed mantle and crustal earthquake distributions and tomographic and receiver function
images from the 2007-2009 southern PUNA passive seismic experiment (see Bianchi et al, 2013,
Tectonophysics).
A strong argument for late Neogene forearc subduction erosion in the southern Central Volcanic Zone region
comes from an ~45 km eastward displacement of the volcanic arc front from ~27°S to 28°S at 8 to 3 Ma. The
glassy andesitic magmas with extreme adakitic signatures (high Sm/Yb and Sr/Yb ratios) that erupted over the
hinge of the shallowing Nazca plate as the Chilean-Pampean flatslab shallowed to the south during this time are
interpreted to contain melt components from the removed forearc lithosphere (Goss, Kay, Mpodozis, 2013,
Journal Petrology). A high attenuation seismic anomaly above the slab, which is present under part of this
region, might be interpreted as being related to a remnant of a subduction channel that carried removed forearc
lithosphere eastward. A geochemical signal of the removed lithosphere is reflected in the isotopic signatures of
the most primitive basalts erupted in the region.
In the backarc, the chemistry and distribution of the giant 6 to 2 Ma Cerro Galan ignimbrites and the < 7 Ma
mafic calc-alkaline and intraplate-like lavas in the southern Puna have been attributed to mantle decompression
melting in the aftermath of delamination of thickened mafic crust as a formerly shallowly dipping subducting
Nazca plate steepened after 7 Ma. A west to east seismic tomographic image through the Cerro Galan caldera
region supports this interpretation in showing an ~100 km long high velocity anomaly above the subducting plate
that is interpreted as the most recently delaminated crust and lithosphere. The low Vs, Vp and high Qp crustal
and mantle seismic anomalies under the areas of young Puna mafic to silicic volcanic rocks are interpreted as
reflecting zones of on-going partial melting in the mantle and crust. Both seismic receiver function images and
calculated mantle equilibration depths of young basaltic magmas attest to a less than 80 km thick lithosphere
under the irregular base of the ~45-75 km thick southern Puna crust. Evidence for ongoing partial melting in the
mantle and crust along with a seismic swarm at < 15 km beneath the > 2 million year old resurgent dome in the
Cerro Galan caldera are consistent with partial melting under the southern Puna plateau continuing the giant late
Neogene ignimbrite flare-up under the Central Andean Puna plateau.
V CONVENCIÓN CUBANA DE CIENCIAS DE LA TIERRA, GEOCIENCIAS´2013.
Memorias en CD-Rom, La Habana, 1 al 5 de abril de 2013. ISSN 2307-499X
IV CONGRESO CUBANO DE PETROLEO Y GAS (PETROGAS´2013)
CESP-C4
CONFERENCIA ESPECIAL
GAS NO–CONVENCIONAL: ¿REVOLUCION ENERGERTICA?
Dr. Manuel Marrero Faz
Ministerio de Energía y Minas de Cuba
Se muestra la definición y los tipos de gas no-convencional (GNC) y sus características
principales .Se presentan los métodos de exploración y producción utilizados para el GNC. Se
informa sobre la producción mundial de gas natural no-convencional y su distribución por
países. Se presentan las áreas más perspectivas para la exploración de GNC en Cuba y sus
posibilidades de ejecución. Se exponen los aspectos relacionados con el medio ambiente y el
GNC .Por último, se ofrecen criterios sobre el futuro inmediato y mediato del GNC .Se ofrecerá
a todos los presentes un GLOSARIO de términos sobre el GNC (en inglés y español).
V CONVENCIÓN CUBANA DE CIENCIAS DE LA TIERRA, GEOCIENCIAS´2013.
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X CONGRESO CUBANO DE GEOLOGÍA (GEOLOGIA´2013)
Conferencias Especiales
CESP-CE5
LÉXICO ESTRATIGRÁFICO DE MÉXICO Y SU UTILIDAD EN LA CARTOGRAFÍA
GEOLÓGICA NACIONAL
Isabel López Palomino(1)
1. Servicio Geológico Mexicano, Boulevard Felipe Ángeles, km. 93.50-4, Col. Venta Prieta, 42080, Pachuca,
Hidalgo, México, [email protected]
Una de las problemáticas más recurrentes en el desarrollo de los trabajos geológicos, es la dificultad en el
reconocimiento de las unidades y sus relaciones estratigráficas fuera de sus áreas tipo. Este problema, es
causado principalmente por el empleo inapropiado e indiscriminado de nombres para las unidades
estratigráficas, lo cual se refleja en la duplicidad de éstos; es decir, se emplea el mismo nombre para unidades
con características líticas diferentes (homonimia) o bien, el uso de diversos nombres para la misma unidad
(sinonimia). Otra problemática persistente es la relacionada con la posición estratigráfica asignada a las
unidades por diferentes autores, la cual, generalmente difieren entre sí, lo que dificulta la interpretación de la
evolución geológica de una región.
De manera particular, esta problemática de la nomenclatura se refleja en los trabajos cartográficos, en los
cuales es extendida la dificultad para identificar y discriminar las unidades estratigráficas fuera de su localidad
tipo; lo que conlleva a renombrar formaciones con términos operativos, que han ampliado el número de
nombres de unidades geológicas y han generado dificultad en el uso apropiado de la nomenclatura
estratigráfica.
Por lo anterior, el Servicio Geológico Mexicano (SGM) tomó la iniciativa de elaborar el primer Léxico
Estratigráfico de México, proyecto que tiene como objetivo analizar y sistematizar la información disponible
acerca del registro geológico de las unidades estratigráficas en el territorio nacional, y conocer el estado actual
de su nomenclatura. Este análisis se desarrolla con apego a los procedimientos establecidos en el Código
Estratigráfico Norteamericano, en sus diferentes versiones, y con la colaboración bajo convenio de algunas
instituciones académicas del país.
Así pues, la homogenización nomenclatural del LEM, debe entenderse como un proceso continuo, en el cual la
comunidad geológica mexicana utilizará una misma nomenclatura estratigráfica en la medida que la información
de las unidades geológicas sea rigurosa, actualizada y de amplia divulgación.
V CONVENCIÓN CUBANA DE CIENCIAS DE LA TIERRA, GEOCIENCIAS´2013.
Memorias en CD-Rom, La Habana, 1 al 5 de abril de 2013. ISSN 2307-499X