XIV CONGRESO LATINOAMERICANO DE GEOLOGÍA
XIII CONGRESO COLOMBIANO DE GEOLOGÍA
o
s
oameric
tin
an
a
l
o
d
e
C
lo
X III
g’a
’a
log
eo
g
XIV C
on
g
r
e
“LAS GEOCIENCIAS PARA EL DESARROLLO DE LATINOAMÉRICA”
e
g
e
so
G
n
o
o
r
Co
l o m bia
no
d
e
Medellín, Colombia
29 de agosto al 2 de septiembre de 2011
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología
Info and abstracts extracted from the official abstract volume of the Congress
IGCP 546 Session
1. Crecimiento y modificación de la corteza en los
bordes de la Placa Caribe
Germany
James PINDELL – Tectonic Analysis Ltd.
Nombre de la charla: The Colombia – Caribbean confrontation;
Plate responses at a continental promontory
England
Coordinadores
Agustín CARDONA – Smithsonian Tropical Research Institute (STRI)
CardonaA@si.edu
Panamá
Marion WEBER – Universidad Nacional de Colombia, Sede Medellín
mweber@unal.edu.co
Colombia
Antonio GARCÍA CASCO – Universidad de Granada
agcasco@ugr.es
España
2. Geodesia espacial y dinámica terrestre
Coordinador
Héctor MORA – Instituto Colombiano de Geología y Minería
(INGEOMINAS)
hmora@ingeominas.gov.co
Colombia
El margen noroccidental de Suramérica se ha caracterizado
por la interacción de las placas Suramérica, Caribe y Pacífico.
Esta interacción incluye, desde el Cretácico Temprano, múltiples
episodios de acreción de terrenos oceánicos diversos (tipo MORB,
arcos de islas y plateaus) al margen continental pre – Mesozoico y
resultó en la formación de complejos de subducción – acreción, los
cuales sufrieron la transición compleja de corteza primitiva a más
evolucionada, a través de diferenciación y génesis magmática.
La obtención de nuevos datos de campo, radiométricos y
geoquímicos ha permitido la revisión de los modelos geodinámicos
vigentes para los Andes del norte y el Caribe, además de aportar
a algunas de las preguntas actuales sobre los modelos de
subducción – acreción tales como la naturaleza de los terrenos
acrecionados, la formación de batolitos en las placas oceánicas
y continentales, la importancia de las zonas de falla responsables
para la redistribución de la margen y la formación de diferentes
cuencas oceánicas.
La sesión especial Crecimiento y modificación de la corteza
en las márgenes de la placa Caribe hará énfasis en la interacción
compleja de la placa Caribe con las placas de Norteamérica y
Suramérica. Se recibirán contribuciones relacionadas con
la identificación de los terrenos acrecionados, las suturas y
las zonas de cizalla, la evolución tectonomagmática de los
complejos de subducción – acreción, el análisis de cuencas, la
formación de corteza continental granítica y las reconstrucciones
paleogeográficas.
Keynote speakers
Walter MARESCH – Ruhr Univeristaet, Bochum
Nombre de la charla:
Margarita Island: the 120 Myr logbook of its journey from
Colombia to the Oriente of Venezuela
Simposio diseñado para poner en consideración y promover
la discusión de un grupo diverso de la comunidad científica
orientado hacia la aplicación de métodos de geodesia espacial
en el entendimiento de la dinámica de la Tierra. Estas discusiones
abarcarán diversas áreas incluyendo pero no restringidas a
deformación, deformación tectónica, rotación de bloques,
deformación volcánica, geodesia de imágenes, cambio climático
global, nivel absoluto del nivel del mar, estudios ionosféricos,
predicción de tsunamis, carga atmosférica, variaciones de
mareas terrestres, carga oceánica, predicción geoidal, dinámica
de corteza profunda y estudios de la criosfera.
3. Isótopos estables tradicionales y no
tradicionales como nuevos proxies en
paleoceanografía, paleoclimatología y
paleobiología
Coordinadores
Juan Carlos SILVA – Universidad de Caldas
jsilvatamayo@yahoo.com
Colombia
Alcides Nóbrega SIAL – Universidad Federal de Pernambuco
sial@ufpe.br
Brasil
Valdrez P. FERREIRA – Universidad Federal de Pernambuco
valderez@ufpe.br
Brasil
Within only a few years, the development of novel mass
spectrometric analytical techniques has allowed using new non
– traditional stable isotopes as promising tools to complement
29
nos permiten reconocer las litologías contenidas en las
Formaciones geológicas que se encuentran en profundidad
mediante el estudio de un parámetro físico, p.e. la aplicación
de Sondeos Eléctricos Verticales.
NW–trending rift intersects the larger NNE–trending Agua
Fria rift of eastern Honduras near Danli. Deposition along
this and other NW–trending depocenters in central Honduras
continued through the Cretaceous before being inverted in the
Late Cretaceous.
Oral Session IGCP 546
Basal stratigraphy of a NW – trending Jurassic rift in
Honduras (Chortis Block)
Robert ROGERS1
1
California State Univeristy – Stanislaus
Palabras claves: Chortis, proto – Caribbean, Jurassic,
Honduras, rift.
orth of Danli in SW Honduras 1300–1500 meters of
Jurassic nonmarine and 1300 meters of marine clastic
strata exposed on limbs of large NW–verging asymmetric folds
reveal a depositional architecture consistent with continental
rifting.
The lowest member (Unit 1) consists of 200–300 meters
of fluvial overbank shale, siltstone and coal unconformably
above basement gneiss. Above the shale (Unit 2) are about
250 meters of alternating very coarse pebble – cobble quartz
and metamorphic clast conglomerates with scoured bases
and overbank shale facies containing plant fragments. This
unit contains at least one 20–meter thick silicic ash – fall
tuff. The coarse conglomerate and shale unit grades upward
into Unit 3, comprised of a 200–meters–thick fine quartz
pebble conglomerate and medium – grained quartz sandstone
with unidirectional crossbeds, channels with scoured bases
and shale from the overbank environments. This is overlain
by Unit 4, approximately 400 meters of fine grained well–
sorted and rounded quartz sandstone in 20–40 meter–thick
units displaying lateral accretion surfaces of a mixed–load
fluvial system. Sand bodies are embedded in shale sequences
representing overbank deposition. Within this unit the steeply
dipping north limb of the Cerro San Cristobal anticline is
comprised of an amalgamated sand body at least 350 to 400
meters thick that represents the location of the axis of the valley
in the Jurassic. This individual sand body was tracked 30 km
to NW through a series of folds. Above (Unit 5) is an abrupt
transition to dark dominantly shale section at least 1300 meters
thick and containing ammonites. There are a number of beds
that coarsen upward to fine–grained sandstone in the shale. A
marine transgressive surface at the top of the fluvial sandstone
is interpreted between Units 4 and 5. Deposition of Unit 5
appears to have been dominated by marine shelf conditions,
and several lower shoreface sand bodies are recognized.
The depositional architecture, thickness and geographic
positions of the strata are consistent with deposition on a
south– or southeast – facing passive margin that resulted from
the breakup of North and South America. The NW trend of
the axial fluvial facies (Unit 4) indicates a large river system
draining from the NW and is consistent with a rift extending
into North America that subsequently failed as the proto
– Caribbean seaway opened between the Americas. This
Procedencia de los sedimentos jurásicos – cretácicos del
flanco occidental de la Serranía del Perijá
Paola Catalina MONTAÑO CORTÉS1, Giovanny NOVA
RODRÍGUEZ1, Uwe MARTENS2, José María JARAMILLO3
1
Universidad Nacional de Colombia – Sede Bogotá
2
Tectonic Analysis Ldt.
3
Gmas Ltda.
Palabras claves: Serranía del Perijá, geocronología U/Pb,
procedencia.
n el Mesozoico la tectónica para el límite norte de la placa
suramericana es de gran actividad. Durante el Triásico
cuando Pangea comienza a romperse, se inicia un periodo
de formación de fosas, que se extiende hasta el Cretácico
temprano, durante este periodo se depositan secuencias
clásticas continentales, capas rojas y depósitos salinos; en la
esquina noroccidental de Suramérica uno de los lugares donde
afloran estas secuencias es la Serranía del Perijá, representadas
por las Formaciones La Quinta y Río Negro.
En este trabajo las lodolitas calcáreas hacia el tope de la
Formación La Quinta se interpretan como depósitos lacustres
mientras que las secuencias de areniscas conglomeráticas
grano – decrecientes e intercalaciones de lodolitas rojas de
la Formación Río Negro se interpretan como depositadas en
ambientes fluviales de ríos trenzados y meandriformes.
Para determinar la fuente de los sedimentos detríticos se
realizaron análisis de geocronología por el método U/Pb en
granos de circones detríticos extraídos de muestras de ambas
Formaciones. En la Formación La Quinta se encontró circones
cuyas edades oscilan entre el Proterozoico y Jurasico Medio
mientras que en la Formación Río Negro se encontraron
circones con edades correspondientes al Meso Proterozoico,
Cámbro –Ordovícico y Triásico – Jurásico.
Finalmente basados en esta información se sugiere que el
área de mayor aporte está localizada en los Andes de Mérida y el
Macizo de Santander; al Este y Sureste de la Serranía del Perijá.
N
E
The Romeral Fault Sytem as a kilometric scale shear zone
in NW Colombian Andes
Cesar Javier VINASCO VALLEJO1, Marion WEBER1, Vicente
RODRÍGUEZ1, Daniel GARCÍA1, María Isabel GIRALDO1
& Carlos ARCHANJO2
1
Universidad Nacional de Colombia
2
Universidade de Sao Paulo
Palabras claves: Romeral Shear zone, Arquía Complex,
Diorita de Pueblito, Caribbean Plate.
hysiographically speaking the westernmost segment of the
Colombian Andes encompasses the Central and Western
P
127
Día 1 • Agosto 31
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología
Día 1 • Agosto 31
GÓMEZ, J. / Editor / Coordinador Técnico
Cordillera as well as the Atrato basin and the Baudo Ranges.
The Central and western Cordilleras are separated by the
Cauca River depression. The geological configuration closely
follows the physiographic trend whereby the two cordilleras
belong to two contrasting domains separated by the Romeral
Fault System (RFS). The RFS encloses a series of rocks
(including the Arquia Complex), which is here interpreted
as an extensive shear zone (kilometric – scale) composed of
multiple lithological units of varying ages, diverse origins,
polydeformed, and in faulted contact. The Pre – Mesozoic
continental margin worked as a Meso – Cenozoic back stop,
which is defined by the actual Central Cordillera. The accreted
terranes are in turn represented by the Western Cordillera,
some of the components of the Arquia Complex and rocks of
the Baudo Range. Despite the complex distribution of reported
ages for the Central Cordillera block, which suggest the
presence of pre – Mesozoic constituents, an Upper Paleozoic –
Lower Mesozoic event is perhaps the most important orogenic
event recorded for the block. This event could be associated
with the build up of Pangea driven by the collision between
Laurentia and Gondwana during the Alleghenian orogeny and
responsible for the subsequent closure of the proto Atlantic
Ocean. Triassic tectonic regime recorded for the Pueblito
diorite suggests a dominant left lateral regime by this time, in
contrast to the dextral dominant regime for the Cretaceous. The
easternmost trace of the RFS is defined by the San Jeronimo
fault. This fault defines the beginning of a broad boundary
that separates the Central Cordillera in the east from the
accreted terranes to the west. Regionally, this broad boundary
corresponds to a kilometric shear zone hosting a series of rocks
including: (1) the Cretaceous sedimentary – volcanic sequence
of the Quebradagrande Complex; (2) low grade devonian(?)
metasediementary rocks of Sinifaná Schists; (3) mafic and
ultramafic Triassic supra subduction intrusives and finally (4)
Permian (?) and/or (?) Cretaceous (?) low to medium grade
meta vulcano–sedimentary N–MORB type sequences of the
Arquia Complex. The Amaga Formation, a coal – bearing,
Oligo – Miocene sedimentary sequence unconformably
covers the older lithological units. Mio–Pliocene volcanic
and subvolcanic rocks of the Combia Formation covered
and intruded the Amaga Formation and other older rocks.
Geometrically, the RFS shear zone is characterized by an
anastomosed arrange of faults yielding a block tectonics
configuration. Different authors agree that the Late Cretaceous
to early Cenozoic tectonic evolution of the northern South
American margin was controlled by its interaction with the
margins of an allochthonous (Pacific – derived), anomalously
thick Caribbean oceanic plate and its associated arc. Subsequent
Palaeogene orogenic phases seem to be related to variations
in plate convergence or to accretionary phenomena (Pindell
et al., 1998; Restrepo – Moreno et al., 2009; Vallejo et al.,
2009; Jaillard et al., 2010). Cardona et al (2011), suggest that
the Caribbean oceanic plate influenced the Late Cretaceous–
Eocene orogeny of the northern Andes by the collision of the
Caribbean arc with the continental margin about 90 Ma with
subsequent installation of the subduction regime possibly
since about 65 Ma. This situation seems to be different from
that of the Central Antioquia segment of the Central Cordillera
where subduction regime is recorded at least since 90 Ma.
Finally, they suggest magmatic quiescence and block uplift
after 50 Ma as product of shallow subduction and oblique
convergence. Regional reconstructions given by Pindell (in
prep) since Jurassic times involves the eastward subduction of
Farallon plate under the continental margin represented by the
Central Cordillera. The result of this subduction is represented
by the Quebradagrande belt containing the arc and back arc
rocks while the Arquia belt contains HP–LT subduction related
rocks. In the model depicted above, the Quebradagrande belt
corresponds to an autochthonous arc contemporaneous to the
Arquia belt produced by eastward subduction of the Farallon
plate. Alternatives hypothesis suggest that Arquia Complex is
a composite collection of rocks including pre–mesozoic and
upper cretaceous fragments. Some of these fragments would be
remobilized pieces from both Central and Western Cordillera
in a long lasting shear zone, developed to the continental
margin since Triassic times, as suggested by ASM studies in
the Pueblito diorite.
Geochemistry of the Santa Fe Batholith in NW Colombia
– Remnant of an accreted Cretaceous arc
Marion WEBER1, Jorge GÓMEZ TAPIAS2, Edison DUARTE1,
Agustín CARDONA3 & César Javier VINASCO VALLEJO1
1
Universidad Nacional de Colombia – Sede Medellín
2
Instituto Colombiano de Geología y Minería –
INGEOMINAS
3
Smithsonian Tropical Research Institute – STRI
Palabras clave: Santa Fe Batholith, Colombian Caribbean
Oceanic Plateau, island arc, Cretaceous.
he Santa Fe Batholith in northern Colombia comprises
gabbros, tonalities to quartzdiorites that intruded the
Cretaceous plateau related basalts of the Barroso Formation,
which are linked to the allochtonous Colombian – Caribbean
plateau.
The tonalitic and quartzodioritic rocks share some
similarities with Archean TTG suites (high Sr and Ba, low Nb
and Y). The primordial mantle – normalized spidergrams are
characterized by negative Nb–Ta and Ti anomalies, suggesting
a subduction related signature. Sr and Nd isotopic data are
strongly homogenous (87Sr/86Sr – 0.70366, eNdi – + 6.7) and
are compatible with melt generation from a mafic source.
Sm–Nd isotopic ages are 98 ± 9.1 Ma, whereas new
incremental heating 40Ar/39Ar date indicates that cooling of
the Batholith occurred around 92 Ma.
The geochemical characteristics and field relations are
similar to those described for the Aruba Batholith (White et
al., 1999) and the Buga Batholith (Villagómez et al., 2008),
T
128
and therefore a similar tectonic setting is probable for the three
units.
It is therefore envisioned that during the late Cretaceous
west dipping subduction zone initiated along the eastern margin
of the Turonian Colombian Caribbean plateau, enabling the
emplacement of the Santa Fe Batholith into basaltic rocks or the
Barroso Formation. During the Maastrichtian these two units
were accreted onto the South American margin, prior to the
formation of a post – collisional continental arc at 65–55 Ma.
References.
White, R.V., Tarney, J., Kerr, A.C., Saunders, A.D.,
Kempton, P.D., Pringle, M.S. & Klaver, G.T., 1999,
Modification of an oceanic plateau, Aruba, Dutch Caribbean:
Implications for the generation of continental crust: Lithos, v.
46, p. 43–68.
Villagómez, D., Spikings, R.A., Seward, D., Magna, T. &
Winkler, W., 2008, New thermochronological constraints on
the tectonic history of western Colombia, in 11th International
Conference on Thermochronometry, Alaska, p. 253–255.
at peak conditions. The apparent geothermal gradient at peak
conditions suggests a collision–related metamorphic event,
probably related to collision and obduction of the Caribbean –
Colombian Oceanic Plateau during the late Cretaceous.
Tectonic evolution of the Leeward Antilles: Late
Cretaceous to Eocene Caribbean – South American
interactions and amalgamation of the Bonaire Block
Roelant VAN DER LELIJ1, Richard SPIKINGS1, Andrew
KERR2, Alexandre KOUNOV3, Michael COSCA4, David
CHEW5 & Diego VILLAGOMEZ2
1
University of Geneva
2
Cardiff University
3
University of Basel
4
United States Geological Survey
5
Trinity College Dublin
Palabras claves: Caribbean, thermochronology, Antilles,
Bonaire Block, accretion.
ny tectonic reconstruction of the evolution of the
Caribbean Plate must account for the timing of accretion
of allochthonous terranes which are currently exposed in the
South Caribbean Plate Boundary Zone (SCPBZ). This 300 km
wide, diffuse plate boundary comprises parts of the Northern
Andes of Ecuador and Colombia, the Coastal Cordillera
of Venezuela, and the mainly submerged Bonaire Block,
whose emergent part forms the Leeward Antilles islands of
Aruba, Curacao, Bonaire and Gran Roque. New zircon U/
Pb, 40Ar/39Ar, apatite fission track and apatite (U–Th)/He data
from the Leeward Antilles constrains quantitative thermal and
exhumation histories, which have been used to propose a new
model for the tectonic evolution of the emergent parts of the
Bonaire Block and the SCPBZ. An east–facing arc system
intruded through an oceanic plateau during ~90 to ~87 Ma, and
crops out on Aruba. Early interactions between the Caribbean
and South American Plates resulted in cooling of the basement
rocks exposed on Aruba, by >80°C at 70–60 Ma. Cooling was
driven by exhumation during island arc and plateau accretion,
to the western margin of Northern South America. Burial
metamorphism of ~95 Ma volcanic arc rocks exposed on
Bonaire was rapidly followed by a major exhumation phase
at 90–80 Ma, forming a major angular unconformity with the
overlying Campanian sedimentary rocks. Exhumation may
have been driven by the collision of a west–facing island arc
with the Caribbean Plate. A second phase of exhumation at
~50 Ma resulted in an angular unconformity with an overlying
fluvial conglomerate hosting Mesoproterozoic gneiss
clasts derived from granulite belts currently exposed in the
Colombian Andes. Island–arc rocks intruded oceanic plateau
rocks on Gran Roque at ~65 Ma and exhumed rapidly at 55–45
Ma. We attribute Maastrichtian – Danian exhumation on Aruba
and early Eocene exhumation on Bonaire and Gran Roque to
sequential diachronous accretion of their basement units to
the South American Plate, resulting in the amalgamation of
A
Thermobarometry of amphibolites from the Arquía
Complex (Central Colombia): Geodynamic implications
Antonio GARCÍA CASCO1, Idael F. BLANCO QUINTERO1,
Elvira Cristina RUIZ2, Mario MORENO2, Luz Mary TORO2,
Arley De Jesús GÓMEZ2 & Cesar VINASCO3
1
Universidad de Granada
2
Universidad de Caldas
3
Universidad Nacional de Colombia – Sede Medellín
Palabras claves: Arquía complex, geodynamic implications,
magnesiohornblende, the Caribbean–Colombian Oceanic
Plateau.
pidote – garnet amphibolite rocks from the Arquía complex
(central Colombia) are composed of magnesiohornblende
+ garnet + epidote + quartz + plagioclase + calcite, plus
rutile + titanite + apatite as accessory phases. The rocks
are fine – to medium – grained, with grains up to 1 mm in
size, though grain size reduction is related to foliation
development during an intense and retrograde deformation
stage overprinting an earlier higher–T foliation. Locally,
fine veins of leucocratic materials appear parallel to the
main foliation, suggesting partial melting of amphibolite.
The cores of magnesiohornblende are relatively rich in AlVI,
NaBand Ti (1.01, 0.49 and 0.06 apfu, atoms per formula units,
respectively), approaching barroisite composition, while
retrograde amphibole is actinolite (AlVI<0.26, NaB<0.15 and
Ti<0.02 apfu). Garnet porphyroblasts are euhedral, partly
replaced by chlorite, and rich in almandine (Xalm= 0.46–
0.60) and grossular (Xgrs= 0.25–0.32). Plagioclase is mostly
albitic, locally reaching oligioclase composition (max. Xan=
0.18). Epidote is clinozoisite with Xpistacite up to 0.27.
Thermobarometric calculations indicate peak metamorphic
conditions of ca. 630 ± 30 ºC and 10.5 ± 1.2 kbar, close to the
wet solidus for basaltic rocks and in agreement with melting
E
129
Día 1 • Agosto 31
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología
Día 1 • Agosto 31
GÓMEZ, J. / Editor / Coordinador Técnico
the Bonaire Block. Widespread unconformities indicate late
Eocene subaerial exposure. Late Oligocene – early Miocene
dextral transtension within the Bonaire Block drove subsidence
and burial of crystalline basement rocks of the Leeward
Antilles to ~1 km. Late Miocene – recent transpression caused
inversion and ~1 km of exhumation, possibly as a result of the
northwards escape of the Maracaibo Block following collision
of the Panama Arc with allochthonous Cretaceous rocks
exposed in the Western Cordillera of Colombia.
depth. Widespread recrystallization, especially in quartz – rich
lithologies, occurred. Another major event at ~ 50 Ma triggered
exhumation of the HP complex into brittle upper crustal levels.
Rb–Sr thin slab techniques on mylonitized Kfeldspar– rich
orthogneiss confirm 50 Ma as the age of the last major isotopic
equilibration. Nine K–Ar results from phengite in strongly
recrystallized HP schists and sheared orthogneiss yield ages
from 56 to 50 Ma. Ar–Ar studies on magmatic amphibole from
unmetamorphosed dykes cross – cutting the HP core indicate
56 to 43 Ma (Kaiser, Ph.D. thesis Bochum, 1996). Zircon
fission – track analyses range from 53 to 37 Ma and indicate
dissection into individual blocks during exhumation into the
brittle crust. The HP core of MAR is now tectonically overlain
by LP greenschist – facies sequences with a conspicuously
different P–T history. These are various metasediments
including thick sequences of marbles and intermediate to basic
metavolcanic deposits. Historically, ages of mid(?)– to Upper
Cretaceous have been assumed from poorly preserved fossils.
However, zircons from a metadacitic “porphyroid” yield a
Triassic eruption age (225 Ma: LA–ICPMS), suggesting that
the protolith for the greenschist – facies tectonic cover was as
heterogeneous as that of the HP core. This LP periphery also
contains trondhjemitic intrusions analogous in composition
and zircon – based age (two at 114: multi – grain; 104,103
Ma: LA–ICPMS) to the widespread trondhjemitic/adakitic
orthogneisses of the HP core. Associated ultramafic rocks are
mainly harzburgite. Periphery and HP core were juxtaposed
before the coeval brittle – ductile transition, as indicated by
analogous cross – cutting dykes and 49 Ma K–Ar phengite
ages on sheared orthogneiss.
The geological history recorded on MAR requires (see
also Pindell, this volume) a collisional event along NW South
America that involved subduction of continental margin
material. Collision must have begun before ~ 120 Ma, in line
with the existence of a west – dipping Caribbean subduction
zone already at this time (Pindell et al., Int. Geology Rev., 2011).
A first major reorganization is indicated by rapid exhumation
at 90–80 Ma, and by calcalkaline intrusions perforating the HP
complex, which was then transported northeastward at depth
in a ductile strike–slip milieu. Final uplift into the brittle crust
occurred at ~ 50 Ma, probably triggered by intra – arc rifting in
the advancing Caribbean Arc, en–route to a Middle Miocene
collision with central and eastern Venezuela.
Acknowledgements: I am indebted to my colleagues
A. Baumann, M. Brix, R. Kluge, F. Koller, J. Pindell, H. P.
Schertl, K.P. Stanek and S. Thomson for allowing me free use
of unpublished data and ideas in this summary.
Margarita Island: The 120 Ma logbook of its journey
from Colombia to the Oriente of Venezuela
Walter V. MARESCH1
1
Ruhr–U
Palabras claves: Margarita Island, high–pressure
metamorphism, arc–continent collision, exhumation history.
etails of the interaction between the Caribbean plate
(CP) and South America (SA) have been modified and
in part obliterated by continuous later tectonic modification.
Much work is still required to summarize and link individual
histories of the dispersed crustal fragments into a coherent
scenario. Rocks exposed on Margarita Island (MAR) not only
record evidence of some of the earliest CP/SA interaction but
also document a particularly far – travelled journey along
northern SA. The core of MAR comprises rocks of both
continental and oceanic affinity that were brought together,
subducted to depths of at least 50 km and metamorphosed at
HP/LT–MT conditions in a subduction zone that must already
have been active at 116–106 Ma, when trondhjemitic/adakitic
anatectic melts intruded rocks of both origins. Zircon – based
ages of ~ 315 Ma (multi–grain), 287 Ma (SHRIMP) and
271 Ma (LA–ICPMS) Ma on various granitic orthogneisses
indicate that Permo – Carboniferous continental basement
was involved. Quartzofeldspathic schists and gneisses,
metaconglomerates, lenticular and massive marbles as well as
graphitic garnet – mica schists predominate. Detrital zircons
indicate Lower Cretaceous ages for these metasediments
(J. Wright, pers. comm., 2010). Rocks of oceanic origin
include MORB–type metabasalts with IAT tendencies.
Abundant ultramafic rocks are predominantly serpentinized
spinel peridotites with common clinopyroxenite/wehrlite.
Correlated primary spinel/olivine compositions suggest a
supra–subduction–zone setting with 40% melt extraction.
The intrusion of potassium–rich granitic rocks between 86
and 82 Ma followed exhumation into middle crustal levels
and signaled a radical change from a HP/LT subduction zone
environment to a MP continental–margin sub – arc setting.
K–Ar, Ar–Ar and Rb–Sr results on rocks and minerals
that were spared later deformation cluster at 90–80 Ma and
substantiate rapid cooling/exhumation at this time. This pulse
of calcalkaline magmatism was immediately followed by a
~ 30 Myr interval of penetrative dextral shearing at ductile
greenschist – facies conditions and relatively constant crustal
D
An alternative to plume for the building of the
Caribbean–Colombian oceanic plateau: insights from new
geologic and chronologic data from Gorgona island
Luca FERRARI1, Lina SERRANO DURÁN2, Margarita
LÓPEZ MARTÍNEZ3, Chiara María PETRONE4 & Carlos
130
JARAMILLO5
Universidad Nacional Autónoma de México – UNAM
2
Universidad de Padua
3
Centro de Investigación Científica y Educación Superior de
Ensenada
4
University of Cambridge
5
Smithsonian Tropical Research Institute
Palabras claves: Caribbean plateau, Gorgona, Slab
window.
ceanic plateaus are considered the result of short – lived
(few Ma) periods of intense submarine volcanism marking
the arrival of mantle plumes at the base of the lithosphere. This
major pulse of volcanism should be followed by a volcanic
chain with ages decreasing away from the site of the plume
head impact. One such an event is postulated to have formed
the Caribbean – Colombian Oceanic Plateau (CCOP) at ~90
Ma, when the Galapagos plume head would have impacted the
Farallon plate. At present, the remnants of the CCOP form the
irregularly thickened and locally deformed oceanic crust of the
Caribbean Sea as well as several highly deformed fragments
obducted in the northern Andes, Central America and the
Antilles. Gorgona island, offshore western Colombia, is one
of the less deformed and last accreted pieces of the CCOP and
its highly heterogeneous igneous suite, ranging from enriched
basalts to depleted komatiites and picrites, was assumed to have
formed at ~89 Ma from different parts of the plume. Based on
our new geologic and geochronologic data we question this
simple mechanism and propose an alternative scenario for the
origin of the CCOP. The island of Gorgona represents the top
of a faulted anticlyne which is part of a series of NNE trending
axial basement bulges formed in Eocene times during the
accretion of a sliver of the CCOP to the continental margin.
These structures were partly disrupted by Miocene to recent
right lateral transtensional and extensional faulting associated
to the post–accretion deformation. Gorgona and the other
submerged basement structures formed the Gorgona terrane,
a >400 km long strike–slip horse bounded by the NE striking
Garrapatas and Buenaventura reverse and oblique fault zones,
which is located between the Western Cordillera and the Serranía
del Baudó. Gorgona mafic lavas and gabbros were thoroughly
sampled and the freshest fragments were dated by the 40Ar–
39Ar method through multiple step–heating experiments using
a laser with the VG5400 mass spectrometer and a Ta–furnace
with the MS–10 mass spectrometer. The experiments show
good reproducibility and document a ~30 Ma long magmatic
activity, spanning the whole Late Cretaceous and part of
Paleocene. A late, shallower, picritic pyroclastic eruption
is constrained to the Paleocene based on stratigraphic and
paleontological data. We obtained a similar age range for the
Bolivar Ultramafic Complex (BUC) of the Western Cordillera
of Colombia, which represent the largest and more mafic
continental exposure of the intrusive complexes of the CCOP.
The time and space distribution of the available CCOP ages,
including our new Gorgona and BUC ages, show a long period
of igneous activity spanning the whole Late Cretaceous. The
prolonged period of igneous activity spanning over ~30 Ma is
not consistent with a short, voluminous outburst of magmatism
from a plume head at ~91–89 Ma, as suggested by previous
authors (e.g. Sinton et al., 1998, EPSL; Kerr, 2005, Lithos).
On the other hand, the geographic distribution of ages does not
point to a definite pattern of migration as it would be expected
if magmatism would be the result of the passage of the Farallon
plate over a stationary, or slowly moving, hotspot. Particularly,
the persistence of magmatic activity at the restricted location
of Gorgona Island is at odds with the model of a volcanic
chain with ages decreasing away from the initial impact site
of a plume head. The distribution of ages rather suggests a
long period of pulsing magmatism in areas up to 1500 km
apart. The data point to a diffuse and irregular magmatism,
consistent with the crustal structure of the Caribbean plateau
seen in seismic profiles. Compared with other classic oceanic
plateau (e.g. Ontong – Java, Kerguelen) the CCOP is thinner
and with a more irregular crustal thickness (between 6 and 15
km), a feature that allowed the subduction of some of its parts
under South America as well as its internal deformation. The
long period of diffuse magmatism that formed the CCOP is
broadly concurrent with the existence of the Caribbean slab
window (~100 to 66 Ma), which must be considered into any
model of the plateau formation. Decompression melting of a
heterogeneous, partly wet, mantle within such a tectonic setting
may explain the observed space–time pattern of magmatism.
We thus speculate that the CCOP melting anomaly may have
resulted from westward flow of Atlantic asthenosphere through
the Caribbean slab window.
1
O
Regional provenance of the late Paleocene to Miocene
San Jacinto belt (Northern Colombia): A record of Late
Cretaceous to Cenozoic continuous convergence in the
Southern margin of the Caribbean plate
Agustín CARDONA1, Camilo MONTES1, Carolina AYALA1,
Camilo BUSTAMANTE1, Camilo MONTENEGRO1, Carolina
OJEDA1, Natalia HOYOS1, Helga NIÑO2, Víctor RAMIREZ2
Daniel RINCÓN3, Víctor VALENCIA4 & Jeff VERVOORT4
1
Smithsonian Tropical Research Institute – STRI
2
ECOPETROL S.A.
3
Instituto Colombiano del Petróleo – ICP
4
Washington State University
Palabras claves: Provenance, Caribbean Plate, Arc –
Continent Collision.
he San Jacinto belt in northernmost Colombia represents a
long and narrow Late Paleocene to Oligocene sedimentary
wedge formed at the southern margin of the Caribbean
plate (Duque Caro, 1984). Understanding its filling history
provides major insights on the Early Cenozoic Caribbean –
South American plate tectonic interactions and the unroofing
of the Northern Andes. A regional provenance analysis
including conglomerate clast counting and whole rock
T
131
Día 1 • Agosto 31
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología
Día 1 • Agosto 31
GÓMEZ, J. / Editor / Coordinador Técnico
E
geochemistry, U–Pb and Hf isotopic granitoid clast analysis,
together with petrographic, heavy minerals and detrital zircon
geochronology was carried on Late Paleocene to Oligocene
conglomerates and associated sandstones. Provenance
results reveal a bi – modal source which can be related to
the erosion of an allochthonous Late Cretaceous arc and the
Late Paleozoic to Triassic continental margin signature. This
compositional signature was followed by a significant increase
in compositional maturity although detrital ages are preserved.
The provenance features can be related to the erosion of the
Late Maastrichtian to Early Paleocene Caribbean – South
America arc–continent collision, whereas the preservation of
the major Late Cretaceous magmatic source and the quartz
increased are related to partial vanishing of the allochthonous
arc source and the major denudation of the Central Cordillera
of the Colombian Andes. It´s also suggested that this changes
record orogen submergence following arc continent collision
and the northeastern lateral displacement of this wedge before
final accretion.
The paucity of Cretaceous detrital ages older than ca. 90
Ma recognized within this belt and other tectonostratigraphic
elements from northern Colombia suggest that the Caribbean –
Americas arc continent collision is more akin to a multiple arc
than the single great Caribbean arc type (Wright and Wylde,
2011; Neill et al., 2011).
References
Duque Caro, H.,1984. Structural Style, diapirism and
accretionary episodes of the Sinu – San Jacinto terrane,
southwestern Caribbean borderland. in Bonini, W.E.,
Hargraves, R.B., and Shagam, R., (eds.), The Caribbean–South
American plate boundary and regional tectonics. Geological
Society of America Memoir, 162, 303–316.
Wright, J. E. & Wyld, S. J. 2011. Late Cretaceous
subduction initiation on the eastern margin of the Caribbean –
Colombian Oceanic Plateau: One Great Arc of the Caribbean
(?). Geosphere, 7, 468–493; DOI: 10.1130/GES00577.1
Neill, I., Kerr, A., Hastie, A., Stanek, K–P. & Milllar,
I., 2011. Origin of the Aves Ridge and Dutch–Venezuelan
Antilles: interaction of the Cretaceous ‚Great Arc‘ and
Caribbean – Colombian Oceanic Plateau?. Journal of the
Geological Society, London, Vol. 168, 2011, pp. 333–347. doi:
10.1144/0016–76492010–067.
ntre la Cuenca de Colombia y las serranía de San Blas–
Darién al sur, limitado al sur occidente por la Falla
Atrato – Urabá, correspondiente a la sutura colisional entre
Centro América y Sur América al oriente afloran una serie de
rocas volcánicas, volcano – sedimentarias, sedimentarias e
intrusivas con edades que van desde el Cretácico Tardío hasta
el Cenozoico. El Complejo Santa Cecilia – La Equis hace parte
de esta secuencia y está constituido por derrames lávicos y
secuencias piroclásticas de composición basáltica a andesítica
de edad Cretácico Superior–Paleoceno, el cual es intruído
por el Batolito de Acandí y demás cuerpos hipoabisales todos
con afinidad de arco volcánico en una suite que varía desde
rocas toleíticas a calco alcalinas. En la zona se describen de
manera informal tres unidades nuevas que corresponden
a las Sedimentitas de Tripogadí, las Brechas de Triganá y
las Sedimentitas del río Cutí, de edades desde el Eoceno
inferior a probablemente el Oligoceno. Las Sedimentitas de
Tripogadí corresponden a una secuencia de aproximadamente
3000 m de espesor que aflora en la Serranía de Tripogadí,
descansa de manera discordante sobre tobas y aglomerados
del Complejo Santa Cecilia – La Equis, pero tiene influencia
del vulcanismo que dio lugar este complejo. Las sedimentitas
de Tripogadi se caracterizan por presentar hacia la base un
fuerte aporte volcánico, desarrollando brechas sedimentarias,
aglomerados volcánicos, intercalados con tobas de ceniza
y lapilli, asociación litológica que marca una influencia
volcánica la cual domina los procesos de sedimentación en
un ambiente marino profundo. En una posición estratigráfica
superior y marcando una posible somerización de la cuenca,
se encuentran areniscas finas a medias con presencia de cuarzo
fino y plagioclasa y hornblenda, intercalado con limolitas,
arcillolitas silíceas y calcáreas, mostrando un carácter bimodal
en composición y una posible sedimentación en ambientes con
aporte volcánico primario o por retrabajamiento de unidades
preexistentes (epiclastitas). La presencia de foraminíferos
y radiolaritas de ambientes pelágicos en las calizas permite
inferir una depositación en ambiente de talud continental con
aportes de detritos cuya fuente es un arco volcánico activo.
Las relaciones de campo y los fechamientos paleontológicos
permiten ubicar dicha formación entre el Paleoceno superior
– Eoceno inferior. Hacia la línea de costa afloran la unidad
denominada Brechas de Triganá, la cual constan de gruesos
paquetes de brechas oligomícticas en la base y polimícticas
hacia el techo, interestratificadas con bancos gruesos de
arcosas, subarcosas, litoarenitas y areniscas conglomeráticas
con estratificación plano paralela. Se considera que esta
unidad corresponde a depósitos de abanicos submarinos y
slumps producto de procesos de levantamiento rápido y altas
tasas de denudación con un área fuente cercana. esta unidad
marca el levantamiento rápido del área, puesto que la fuente de
aporte de las Brechas de Triganá en la base es el arco volcánico
(Complejo Santa Cecilia La Equis) y hacia la parte superior lo
que aflora corresponde a un orógeno levantado. El origen de las
Brechas de Triganá es la respuesta al proceso de levantamiento
tectónico en el Eoceno o ligeramente posterior al Eoceno, del
arco magmático representado por Complejo Santa Cecilia – La
Las Sedimentitas de Tripogadi y las Brechas de Triganá:
Un registro de volcanismo de arco, corrientes de turbidez
y levantamiento rápido Eoceno en el noroccidente de Sur
América
María Isabel SIERRA ROJAS1 & Gabriel RODRÍGUEZ
GARCÍA2
1
Universidad Nacional Autónoma de México – UNAM
2
Instituto Colombiano de Geología y Minería –
INGEOMINAS
Palabras claves: Sedimentitas de Tripogadí, Brechas de
Triganá, turbiditas, arco volcánico.
132
Equis y el Batolito de Acandí. Ambas formaciones registran
la evolución de un margen continental con procesos volcano
tectónicos activos y depositación de abanicos submarinos
y turbiditas (Sedimentitas de Tripogadí), registrando en la
unidad de Brechas de Triganá un levantamiento rápido del
arco, acompañada de una erosión de grandes dimensiones o
catastrófica, que erosionó parte del arco volcánico y alcanzó
a erosionar las rocas plutónicas y subvolcanicas (Cuerpos de
pórfidos y Batolito de Acandi).
sedimentation occurred along the Cauca depression to the
north of the Garrapatas Fault, mixed marine – siliciclastic
sedimentation occurred to the South of this tectonic feature.
The Garrapatas Fault is the main tectonic feature separating
the Cretaceous Choco Block from the Ancestral Western
Cordillera of Colombia. We suggest that a possible geographic
barrier developed along the Cauca depression. Such geographic
and hydrographic barrier would have been related to tectonic
up–lift of the ancestral Western and Central Cordillera, north
of the Garrapatas Fault. Such uplift (ca 23 Ma) may have
ultimately been related to the initial interaction of the Pamana
– Choco block with northern South America. This scenario is in
agreement with our interpretation that the Oligocene – Miocene
siliciclastics cropping out along the Cauca depression, north
of the Garrapatas Fault, were deposited along intra–mountain
basins confined between the Western and Central Cordilleras
of Colombia, while those cropping out to the south of the
Garrapatas would have been deposited along coastal plains
draining towards the south. The occurrence of siliciclastic
Paleocene – Eocene mixed continental – marine sedimentary
successions and early Oligocene coral reef successions (Vijes
Formation) overlying the basement of the Western Cordillera
of Colombia, south of the Garrapatas Fault, further support
this interpretation and may suggest an interaction between
the Choco Block and NW South America dating back to early
Cenozoic times.
Source area lithology controlling the composition of
the siliciclastic fill in intra – mountain Cenozoic basins:
Implication for the Paleogeography of NW South America
Juan Carlos SILVA TAMAYO1,2, Andrés PARDO1, Agustín
CARDONA2, Germán BAYONA3, Carlos BORRERO1 &
Sergio RESTREPO2
1
Universidad de Caldas
2
Smithsonian Tropical Research Institute – STRI
3
Corporacion Geologica ARES
Palabras claves: NW South America paleogeography, Intra
mountain basins, Amaga Formation, Tectonic evolution,
Colombia.
he tectonic evolution of NW South America since the late
Cretaceous to the present has been closely related to the
evolution of the Caribbean Plate and its interaction with the
South American Block. Changes in tectonic regime along NW
South America and major variations in the neotropical climate
seem to have likely affected the sedimentologic, stratigraphic
and compositional characteristics of siliciclastic successions
cropping out along some of the Oligocene – Miocene basins of
NW South America (i.e. the Amaga and Santa Fe de Antioquia
– San Jeronimo basins, Van der Hammen, 1958, Pons 1984;
Silva Tamayo et al., 2008).
The Oligocene – Miocene Amaga Formation crops out along
of the Cauca depression in NW Colombia. Previous studies
have suggested that the Amaga Formation was deposited in
several confined intramountain basins occurring along the
Cauca depression (Silva Tamayo et al., 2008). Here we present
new sedimentologic and stratigraphic, along with new detrital
compositional modes of the Amaga Formation (along the Santa
Fe de Antioquia – San Jerónimo Basin) that further account for
deposition of the Amaga Formation silicilastics along intra –
mountain basins. Local compositional similarities between the
siliciclastic record and the underlying basements and regoliths
suggest a provincialism in the sediment provenances. Such
provincialism and the preferential south – north paleocurrent
directions further account for a fluvial system functioning
similarly to the modern Cauca River (Silva et al., 2008).
The sedimentologic, stratigraphic and sandstone
compositional characterisitics of the Amaga Formation
contrast with those displayed by other Oligocene – Miocene
siliciclastic successions cropping along the Cauca depression,
but to the south of the Garrapatas Fault (i.e. the Cinta de
Piedra, Mosquera and Esmita formations). While continental
T
The transpressive left – lateral Chiapas Mountain Chain
and its buried front in The Tabasco Plain (South Mexico)
Cesar Augusto WITT OLIVO1, Stephanie BRICHAU2, Andrew
CARTER3 & Claude RANGIN4
1
GEOAZUR
2
Institute of research for development – IRD
3
Birkbeck College – London
4
Collège de France
Palabras claves: Chiapas, Polochic – Motagua, Punto triple,
Placa Caribe.
he Chiapas mountain chain (CMC) evolved in the vicinity
of the triple junction between the Cocos, North America
and Caribbean plates. Major exhumation and topographic
growth occurred during the middle – late Miocene (16–10
Ma). This deformational event is evidenced by fault activity,
major stratigraphic unconformities along the CMC and the
Tabasco coastal plain (i.e. southern Gulf of Mexico), major
salt–related motion and northward progradation of sediments
and by the northward migration of the buried deformational
front. During Neogene, strike slip deformation and related
exhumation has migrated landwards from the western edge
of the Chiapas massif to the Chiapas Sierra. Horizontal
displacement along the main strike – slip faults on the Sierra
may be comprised between 30 and 43 km during the last
6–5 Ma involving 0.5–0.8 cm/a of lateral accommodation.
These values suggest that a significant amount of the motion
T
133
Día 1 • Agosto 31
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología
Día 1 • Agosto 31
GÓMEZ, J. / Editor / Coordinador Técnico
transferred from the Caribbean and North American plates
is currently accommodated along the Chiapas area. The
CMC tectonics reflects positive topographic growth along
its main core and a northwards – directed collapse trough a
free–border related to the Gulf of Mexico. In this scenario,
the CMC formation enhances earlier pervasive deformation
mainly triggered by earlier periods of salt motion along
the Tabasco coastal plain. Sediment provenance and low
temperature thermochronology (apatite fission track and
(U–Th)/He) study on igneous and terrigenous samples of
the Chiapas mountain chainyielded important constraints for
the chain evolution and its relationships with the Caribbean,
North America and Cocos triple–junction. Results show that
Palaeocene – Eocene terrigenous units (outcropping at the
northern section of the Sierra) were derived from Grenville
(~1Ga) basement whereas internal section of the chain
display Chiapas massif–derived (270–250 Ma) components.
Grenville–sourced sediments are probably derived from a
Laramide deformation front and deposited in an open marine
to continental environment north of the Sierra. Sediment
input related to this process seems important due to the high
degree of resetting of AFT and (U–Th)/He systems at site.
Batholith – related input increases with the onset of major
tectonic deformation at 16–9 Ma. Apatite fission track and
(U–Th)/He data combined with previously published results
define three main exhumation periods: 1) A slow 40–25 Ma
exhumation affecting the massif and relatively unexpressed
along the Chiapas Sierra; 2) A fast 16–9 Ma exhumation
period related to the onset of major strike slip deformation
related to the Caribbean – North American plates limit and
affecting both Chiapas massif and Chiapas Sierra; and 3) A
6 – 5 Ma period affecting the Sierra and coincident with the
landward migration of the plate limit. Stratigraphic, cinematic
and termochronologic evidence suggests that the left – lateral
strike – slip faults bounding the Chiapas Sierra to the west
accommodates most of the current displacement between the
North American and Caribbean plates.
the Southern Caribbean Deformed Belt accretionary prism,
the Caribbean subducts under South America. In a manner
of speaking the two plate subduct beneath each other. Finite
– frequency teleseismic P–wave tomography confirms this,
imaging the Atlantic and the Caribbean subducting steeply in
opposite directions to transition zone depths under northern
South America (Bezada et al, 2010). The two subduction zones are connected by the El Pilar–San
Sebastian strike–slip fault system, a San Andreas scale system.
A variety of seismic probes identify where the two plates tear
as they begin to subduct (Niu et al, 2007; Clark et al., 2008;
Miller et al. 2009; Masy et al, 2009). The El Pilar system forms
at the southeastern corner of the Antilles subduction zone by
the Atlantic tearing from South America. The deforming plate
edges control mountain building and basin formation at the
eastern end of the strike–slip system.
In northwestern South America the Caribbean plate
tears, its southernmost element subducting at shallow angles
under northernmost Colombia and then rapidly descending
to transition zone depths under Lake Maracaibo (Bezada et
al., 2010). We believe that the flat slab produces the Merida
Andes, the Perija, and the Santa Marta ranges. The southern
edge of the nonsubducting Caribbean plate underthrusts
northern Venezuela to about the width of the coastal mountains
(Miller et al., 2009). We infer that the underthrust Caribbean
plate supports the coastal mountains, and controls continuing
deformation.
The Colombia – Caribbean tectonic confrontation; plate
responses at a continental promontory
James PINDELL1
1
Rice University and Tectonic Analysis Ltd.
Palabras claves: Subduction accretion, arc, rifting, plate
motions.
volving concepts of Caribbean evolution since 1970 show
advantages of considering regional evolution in the mantle
reference frame, because subducted slabs in the mantle can
only migrate forward/backward at a fraction of plate motion
rates and thus the “room” for error is much less (Pindell and
Kennan, 2009). From Triassic to Early Cretaceous, northern
South America remained attached to Africa, both moving
little relative to the mantle in contrast to North America’s
NW–ward migration, leading to Jurassic rifting and drifting
between the Americas. By Aptian (125Ma), opening of the
Equatorial Atlantic had begun, and northern South America
has migrated westward across the mantle ever since, thereby
throwing subduction systems and intra–arc basins along the
NW Andes into E–W compression sensu Dewey (1980), with
variable strike slip components. This long – lived compressive
period comprises unique phases of convergent tectonic
style between the NW corner of South America (Colombian
continental promontory) and lithosphere that was either driven
by, or belonged to, the Caribbean Plate.
E
Subduction in the Southern Caribbean
Alan LEVANDER1, Michael SCHMITZ2, Maximiliana
BEZADA3, Meghan S. MILLER4, Jeniffer MASY1, Fenglin
NIU1 & James PINDELL1
1
Rice University
2
Fundación Venezolana de Investigaciones Sismológicas –
FUNVISIS
3
University of Oregon
4
University of Southern California
Keywords: Southern Caribbean plate boundary, subduction,
mountain building.
he southern Caribbean is bounded at either end by
subduction zones: In the east at the Lesser Antilles
subduction zone the Atlantic part of the South American plate
subducts beneath the Caribbean. In the north and west under
T
134
In Early to Middle Jurassic, granitic intrusives were
produced and cooled in a “Central Cordilleran” belt from
Guajira into Ecuador, usually presumed to be arc magmas
from E–dipping subduction. However, they may relate to
rifting within a zone of crustal anatexis caused by Alleghanian
– Gondwanan crustal thickening of Late Paleozoic arc –
related terrane. Following the arc model, I have proposed the
opening of an intra – arc basin as a means of terminating this
“arc” by 140–150 Ma (Pindell, 1993), but the anatexis model
can pertain only to Jurassic rifting, without subduction, of
Mexico/Chortis from Colombia (Pindell and Dewey, 1982).
Redbed deposition on phaneritic intrusive rock (eg, Saldaña
Fm on Ibague pluton) attests to syn – magmatic extension and
exhumation of deep terrane, fitting either model. But the arc
model predicts evolution of an offshore active arc from 145–
125 Ma; such ages on arc rocks are rare/absent in Colombia/
southern Caribbean, making this an issue for investigation.
The NW–ward flight of North America probably created
an archipelago of stretched arc and continental blocks from
Mexico and Chortis along a SE – trending and lengthening
sinistral shear zone/transform to the Andean intra–arc basin
(Pindell et al. 2011), which can be called Quebradagrande
Basin. 125Ma opening of the Equatorial Atlantic and onset
of Andean compression caused this basin and its outlying
Quebradagrande Arc to collapse, achieved by dextral and
W–dipping subduction such that the Central Cordilleran
margin choked the trench during arc collision, as shown by
Margarita which hosts a far–travelled remnant of this event
(Maresch, this volume). The collision involved propagation
of transpressive faults into the continental margin, parts of
which were uplifted and cooled (Villagomez, 2010), and
probably carried northward along orogen–parallel shears.
However, E–dipping subduction of Farallon Plate outside
Quebradagrande Arc, marked by the Arquila HP–LT complex,
probably continued throughout closure of the weak backarc
basin, and after arc accretion.
The Caribbean – Colombian intra – oceanic oceanic
plateau (CCOP) then formed on Farallon/Caribbean crust at
about 110–88Ma and progressively converged with Colombia,
accreting slices of the plateau into a wide subduction prism
as it encountered the E–dipping trench outboard from the
Quebradagrande/Arquila belts. Subduction – related magmas
intruded inner parts of the prism (Buga Batholith) and adjacent
continental margin (eg, Antioquia and other batholiths) from
about 100–75Ma. Margarita was situated beyond the northern
end of this setting, where a lengthening NE–trending dextral
shear zone connected the Colombian trench to the eastern,
W–dipping, Caribbean trench. The CCOP followed Margarita
and, like Margarita, began to receive Caribbean arc magmas
by 89Ma as the Caribbean arc lengthened due to the shear, to
include the Aves Ridge, Margarita and the Leeward Antilles
(Wright and Wyld, 2010).
The Late Cretaceous Andean setting of plateau subduction/
accretion prevailed until Maastrichtian, when Andean
“Laramide” orogenesis was initiated by 1, CCOP buoyancy;
2, acceleration of CCOP orthogonal subduction (Pindell
and Kennan, 2009); and 3, westward acceleration of South
America across the mantle (Pindell and Tabbutt, 1995). By
Middle Eocene, much of Colombia had become subaerial
with multi–kilometric uplift and erosion of material from the
Colombian hanging wall as it telescoped across the Caribbean
Benioff Zone, thereby effecting flat slab subduction. Cenozoic
Caribbean arc magmas are limited to Early Paleogene partial
melts of downgoing slab in the Santa Marta region (Cardona
et al., 2010). Late Eocene reduction of plate convergence
allowed deposition to resume in Colombia, but by Oligocene,
the Caribbean’s west–facing arc (Panama) began to enter
and choke the trench. This, combined with rejuvenated plate
compression at 25 Ma, initiated the “Andean” Orogeny that
persists today.
Análisis de vulnerabilidad aplicando herramientas SIG en
la cuenca del arroyo de la Quebrada de Los Filtros, Jujuy
– Argentina
Llanos VALERA PRIETO1, Susana A. CHALABE2 & Reinhold
Siegfried WEIGERT2
1
Universidad Nacional de La Plata – UNLP
2
Universidad Nacional de Jujuy
Palabras claves: Vulnerabilidad, SIG, Cuencas.
a presente investigación se realizó en el marco de la Maestría
en “Manejo Integral de Cuencas Hidrográficas” de la Facultad
de Ciencias Agrarias y Forestales de la Universidad Nacional
de La Plata (Argentina), en virtud de una ayuda económica
otorgada por la Agencia Española de Cooperación Internacional
(AECID). Tiene como objetivo evaluar la vulnerabilidad de
una población ante eventos extremos y por ello se seleccionó la
cuenca de la Quebrada de Los Filtros, Jujuy, Argentina, que por
sus particulares características geológicas, tectónicas y climáticas
se distingue por ser un ambiente muy inestable que facilita el
desarrollo de procesos geodinámicos intensos; estos producen
movimientos de masa entre los que se encuentran deslizamientos,
derrumbes y flujos densos que se constituyen en amenazas
naturales recurrentes para esta cuenca. Gran parte de la ciudad
de Volcán se localiza en este ámbito, situación que ha provocado
que en numerosas ocasiones esta se vea inundada por coladas
de barro y flujos densos. Los incidentes ocurridos movilizaron
a la comunidad quienes plantearon la necesidad de analizar la
vulnerabilidad para establecer pautas y protocolos de actuación
en caso de que ocurra un desastre. El análisis de la vulnerabilidad
implicó realizar un estudio detallado a nivel de parcelas,
desagregando la vulnerabilidad en física, ambiental y ecológica,
social, política e institucional, educativa, económica, cultural e
ideológica y científica y tecnológica. Para la recolección de los
datos necesarios que la investigación requería, se combinaron
fuentes de información primaria y secundaria aplicando el método
inductivo–deductivo a través de la observación directa, la técnica
de encuestas y se realizaron entrevistas y cuestionarios. Por otra
L
135
Día 1 • Agosto 31
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología
de las curvas de SEV en diferentes condiciones geológicas
estudiadas, las cuales pueden ser tomadas como referencia
en cualquier proyecto relacionado con la búsqueda de aguas
subterráneas.
Palabras claves: Subcuenca de Plato, Interpretación Sísmica,
Gravimetría.
través de la interpretación de un transecto sísmico
regional y varias líneas auxiliares y la correlación con
información de registros de pozo y bioestratigrafía, se propone
un modelo tectonoestratigráfico en la subcuenca de Plato, en el
Valle Inferior del Magdalena. Se identificaron las principales
discordancias estratigráficas y se definieron cinco unidades
tectonoestratigráficas que registran la evolución de la subcuenca
desde su activación como cuenca transtensional en el Oligoceno
hasta el Reciente. Las unidades U1 y U2 se depositaron en
el Oligoceno al Mioceno Temprano durante una etapa de
transtensión y colapso tectónico asociado a la colisión oblicua
entre las placas Caribe y Suramérica. La unidad U1 constituye
la secuencia basal transgresiva, principal roca reservorio en
la cuenca y probable roca generadora. Las unidades U3 y
U4 corresponden a una fase de subsidencia pronunciada
durante el Mioceno medio – tardío. La unidad U5 se deposita
durante el pulso más pronunciado de la orogenia Andina en
el Plioceno, etapa en la que se interpreta un basculamiento de
la cuenca e inversión del principal depocentro. Se establece
una correlación entre la interpretación sísmica y gravimétrica
mediante la integración de ambos métodos geofísicos,
confirmándose de esta manera conceptos geológicos en el
área de estudio. En el mapa de Anomalía Residual se delinean
rasgos tectónicos como los altos El Difícil, Cicuco, Apure,
Ayhombe y la Plataforma de Chimichagua, las depresiones de
Plato, Sucre y Bálsamo, así como el Sistema Romeral. En la
subcuenca de Plato se revelan dos depocentros bien definidos
separados por un alto de basamento. El modelo gravimétrico
confirma la presencia de un basamento de afinidad continental
en la subcuenca, presentando una densidad de 2,67 g/cm3. El
espesor de la corteza disminuye de noreste a suroeste de 29
km a 22 km, resultado que concuerda con estudios corticales
realizados en la región
A
Interpretación de registros de voladuras por medio de
softwares, Boyacá, Colombia
María Del Carmen FUENTES FUENTES1
1
Universidad Pedagógica y Tecnológica de Colombia –
UPTC
Palabras claves: Geofísica, Voladuras, Geociencias,
acelerógrafos, INGEOFISICA
l control de vibraciones implica la medición de estas
perturbaciones en una voladura de producción. Si el
nivel de vibraciones registrado fuera menor que el criterio de
prevención, podrá incrementarse progresivamente la carga
operante hasta que las intensidades de vibración fueran iguales
al valor máximo admisible, de tal forma que los análisis
realizados en éste articulo sirvan como estudios preliminares
para establecer una tabla patrón de cargas máximas por
microretardo contra la distancia a las estructuras a proteger en
función de la velocidad ó aceleración de la partícula.
E
Investigación geofísica compleja, análisis geoestadístico
y modelación 3D, con métodos eléctricos y nucleares en
Macanal y Chinavita, Boyacá, Colombia
Freddy Alexander FONSECA BENÍTEZ1
1
Universidad Pedagógica y Tecnológica de Colombia –
UPTC
Palabras claves: Geofísica, Geoélectrica y radiometría,
Geociencias, acelerógrafos, INGEOFISICA.
La implementación de los métodos geofísicos en el
departamento de Boyacá es vital en la realización de proyectos
que nos permitan evaluar geológico–geofísicamente las
formaciones geológicas y específicamente las unidades
litologías presentes en ellas. A continuación se presenta el
marco geológico de la zona de estudio en la cual se realizo
la exploración geofísica así como los fundamentos físico –
geológicos, la metodología de los trabajos de campo y los
resultados obtenidos a partir de la implementación de métodos
eléctricos y el método de radiometría. De igual forma se
realizo un análisis geoestadístico de los datos y comparación
entre poblaciones por medio de histogramas de frecuencias de
los parámetros físicos medidos.
Poster Session IGCP 546
Geochemical and geochronological tests for the Caribbean
tectonic setting of early Paleocene partial melting in the
Sierra Nevada de Santa Marta (Colombia)
Jakeline VANEGAS ARROYAVE1, Agustín CARDONA2,
José Fernando DUQUE TRUJILLO3, Antonio GARCÍA
CASCO4, Víctor VALENCIA5, Jeff VERVOORT5, Samuel
JARAMILLO2 & Marion WEBER1
1
Universidad Nacional de Colombia, Sede Medellín
2
Smithsonian Tropical Research Institute – STRI
3
Universidad Autónoma de México – UNAM
4
Universidad de Granada
5
Washington State University
Palabras claves: Partial melting, Caribbean, geochemical
modelling, tectonics.
ecent geochronological and geochemical constraints
from plutonic rocks in the northwestern segment of the
Sierra Nevada de Santa Marta have reveal the existing of two
Evolución cenozoica de la subcuenca de Plato, Valle
Inferior del Magdalena, Colombia
Lorena SUÁREZ BERMÚDEZ1 & Crelia PADRÓN DE
CARRILLO2
1
Pacific Rubiales Energy
2
Universidad Simón Bolívar
R
227
Día 1 • Agosto 31
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología
Día 1 • Agosto 31
GÓMEZ, J. / Editor / Coordinador Técnico
highly contrasting magmatic suites (Duque, 2010; Cardona
et al., 2011). The older magmatism (ca. 63–65 Ma) includes
micaceous granites and dykes which are spatially associated
with amphibolitic rocks. This magmatism is temporally
unrelated with a broader and apparently more standard tonalite
to granodiorite arc plutonism formed between 58–50 Ma.
Geochemical characteristics from the older granites includes
low Y and HREE that reseambles both high silica adakites and
TTG and have been interpret to the melt of basaltic rocks. To
model the origin of this magmatism and its tectonic context
additional field work on the granitic rocks and the associated
amphibolites, geochemical modelling and geochronological
constrains from the Cretaceous metamorphic rock of Santa
Marta are in progress. Field relations near Playa Salguero
(near the town of Santa Marta) highly interspersed leucratic
veins and dikes and more extensively widespread granitic
bodies that intrude de metamorphic host rocks. This feature
suggest that this crustal is probabbly more link to an area of
melt accumulation within a migmatitic terrane. Whereas new in
published geochemical data from the host metamorphic rocks
suggest a basaltic protolith formed in MORB to arc tectonic
setting. Preliminary hypothesis for the tectonic setting of this
partial melting event preceeding the a shor duration arc setting
include: 1) closure a thickening of the accreted intra – oceanic
back – arc, 2) slab brek off after arc–continent collision,
3) melting of the upper crust thickened during subduction
initiation.
tamaños de la biotita: en el sector sureste los cristales son
ehuedrales a subhedrales con textura poikilitica y alcanzan
hasta 1 cm. En el noroccidente el tamaño de grano alcanza hasta
0,5 cm. El Stock de Parashi se caracteriza por presentar una
masa granodiorítica principal cortada por abundantes diques
de andesita y dacita porfirítica. Las edades de cristalización
definidad por el método U–Pb en ambas litologías son
relativamente próximas entre sí, sobreponiéndose en error
y por lo tanto sugiriendo que las variaciones texturales son
parte de un proceso magmático continuo. Las variaciones en
el tamaños de los cristales observadas en estos dos cuerpos
sugiere claramente la existencia de una inestabilidad en la
historia de cristalización de los magmas. Estas variaciones
podrían estar relacionadas con el crecimiento y cristalización
de estos cuerpos en un ambiente de tectónica activa donde
existiría una exhumación contemporánea con la cristalización,
así como niveles de exposición variables (caso Hatillo), o
simplemente reflejarían variaciones en los contenidos de agua
en el sistema.
Middle Miocene volcanism within the south Caribbean
deformed belt in northern Colombia: Petrotectonic
implications
Mario Enrique LARA OCAMPO1, Agustín CARDONA2,3,
Víctor VALENCIA4, Marion WEBER5, John CERON6, Felipe
DE LA PARRA7, Diana ESPITIA7 & Margarita MARTÍNEZ8
1
Universidad Nacional de Colombia
2
Smithsonian Tropical Research Institute – STRI
3
Corporación Geológica Ares
4
Washington State University, Pullman
5
Universidad Nacional de Colombia, sede Medellín
7
ECOPETROL S.A.
6
Instituto Colombiano del Petróleo
8
CICESE; México
Palabras claves: Slab roll back, Volcanism, South Caribbean
deformed belt.
ew field, petrological, geochemical and Ar–Ar
geochronological results reveals the existence of a
Middle Miocene basaltic volcanism within the Oligo–Pliocene
continuation of the South Caribbean deformed belt in onshore
Colombia (Sinu belt after Duque–Caro, 1984). Geochemical
characteristics of this volcanism including LILE enrichment
and Nb and Ti negative anomalies suggest that this magmatism
was formed by the melting of a subduction modified mantle,
formed by relatively shallow melting as suggested by their
1.1 to 1.3 Ce/Y ratios (Mantle & Collins, 2008). Available
geophysical models and geodetic constraints from the northern
margin of South America have shown the existence of a flat
slab subduction configuration and slow plate convergence
relations (van der Hilst & Mann, 1994; Toto & Kellogg, 1992,
Weber et al., 2001). We suggest that this volcanism formed
within a commonly considered amagmatic margin is link to a
slab roll back event formed as the upper plate (Northern Anden
Análisis de la distribución del tamaño de cristales (CSD)
en los stocks eocenos del Hatillo (Cordillera Central)
y Parashi (Península de La Guajira): Implicaciones
petrotectónicas
Camilo BUSTAMANTE1, Agustín CARDONA2, Carlos
ARCHANJO1 & Camilo MONTES2
1
Univerdidade de Sao Paulo
2
Smithsonian Tropical Research Institute – STRI
Palabras claves: Crystal Size Distribution, Stock del Hatillo,
Stock de Parashi.
as características texturales de las rocas graníticas están
controladas en parte por la competencia entre los procesos
de nucleación y crecimiento. Variaciones en las condiciones
fisicoquímicas del magma (contenidos de agua, mezcla de
magmas) o modificaciones en el nivel de emplazamiento pueden
causar cambios significativos en el tamaño de los cristales y
la distribución de los minerales. Los stocks del Hatillo en la
Cordillera Central y Parashi en la Península de la Guajira son
rocas plutónica de Edad Eocena cuya historia de generación
magmática y emplazamiento se encuentran aparentemente
relacionada con el reinicio de una nueva subducción que
siguió a la colisión entre el arco del Caribe y Suramérica y por
lo tanto en términos tectónicos y de generación de magmas
representa un escenario propicio a condiciones cambiantes.
El stock del Hatillo presenta importantes variaciones en los
N
L
228
block) accelerates to the northwest due to the Panama–South
America plate convergence.
esquistosos estaría asociado con el material derivado de la
Cordillera Central o al retrabajemiento de este mismo material
en secuencias sedimentarias más antiguas depositadas sobre
la Cordillera Occidental. Estos resultados sugieren que para
el Mioceno Inferior a Medio la colisión entre del BCP y la
margen continental de Suramérica ya estaría en proceso, lo
que indica un carácter más temprana para este evento (Farris
et al., 2009, Montes et al., 2010) que contrasta con la edad
Miocena Superior–Pliocena previamente sugerida con datos
paleontológicos (Duque Caro et al., 1990). Adicionalmente
la presencia de feldespatos y plagioclasa sugiere que el BCP
habría experimentado una exhumación significativa hasta
exponer niveles corticales superiores a medios del arco
volcánico. REFERENCIAS Farris, D., Cardona, A., Montes,
C., Jaramillo, C., 2009. Demise of arc magmatism along
the Panama Canal. Geological Society of America, Annual
meeting. Paper 79–1 Montes, C., Cardona, A., Bayona, G.,
Silva, C., Farris, D., Moron, S., Wilson, J., Valencia, V., 2009.
Structural transects across the isthmus of Panama: Orocline
or subduction–related. Geological Society of America, Annual
meeting. Paper 79–2 Duque–Caro et al., 1990. Neogene
stratigraphy, paleoceanography and paleobiogeography in
northwest Sout america and the evolution of the Panama
Seaway., vol 77, p 203–234
Procedencia de las formaciones neógenas Pavo y Arenas
Monas, Cuenca de Urabá, Caribe colombiano: Relación
con la colisión del Bloque Chocó – Panamá
Sandra Catalina MÉNDEZ ESPINOSA1, Pedro PATARROYO
GAMMA2, Agustín CARDONA3, Camilo MONTES4, Juan
Manuel MORENO MURILLO2 & Pedro Pablo VILLEGAS5
1
Centro de investigación GMAS Ltda.
2
Universidad Nacional de Colombia, Sede Bogotá
3
Instituto Smithsoniano de Investigaciones Tropicales –
STRI
4
Corporación Geológica ARES
5
CORPOURABÁ
Palabras claves: Neógeno, Análisis de procedencia, Sutura
Uramita, Apartadó, Urabá.
n zonas de colisión y acreción de terrenos, la edad de las
suturas y los niveles corticales asociados a la colisión
están comúnmente registrados en las secuencias sedimentarias
que se depositan sobre la sutura y los bloques suturados. En el
Urabá Antioqueño, a lo largo de los ríos Apartadó y la quebrada
Cuchillo se encuentran expuestas las formaciones Pavo de edad
Mioceno Inferior a Medio y Arenas Monas de edad Mioceno
Superior a Plioceno Superior. Estas unidades sedimentarias
se depositaron sobre la sutura entre el arco intraoceánico
Chocó – Panamá (BCP) y los Andes del Norte. La Formación
Pavo incluye areniscas subangulares, composicionalmente
corresponde a arcosas líticas, litoarenitas feldespáticas y
litoarenitas con importantes porcentajes de cuarz con 27,6%
– 49,5 %. Los feldespatos más abundantes son los potásicos,
generalmente están sericitizados y es más evidente cuando
la roca presenta matriz arcillosa. Las plagioclasas son de
composición cálcica. Los fragmentos líticos más abundantes
son los sedimentarios que incluyen chert y en menor proporción
de cuarzoareniscas y lodolitas laminadas. Los fragmentos
volcánicos son principalmente de tipo andesítico, consisten
en cristales de plagioclasa embebidos en una matriz vítrea.
En menor proporción se presentan fragmentos de esquistos
y filitas. La Formación Arenas Monas incluye litoarenitas
volcánicas con cuarzo y fragmentos líticos. Estos últimos
incluyen material tobaceo con textura de tipo shard, además
lodolitas y cuarzoareniscas. Las inmadurez composicional
y textural marcada por la presencia de feldespatos y líticos
altamente inestables (material volcánico), así como por
el carácter angular sugiere que las fuentes de aporte son
relativamente proximales y estarían relacionadas a la erosión
de un terreno volcano–plutónico y sedimentario. Este bloque
aportante podría corresponder al Complejo Santa Cecilia–La
Equis y el Batolito de Mande que constituyen el armazón
del BCP, mientras que el abundante aporte sedimentario
estaría relacionado con el Grupo Cañasgordas asociado a la
Cordillera Occidental. La presencia de líticos metamórficos
E
Mapeamento de cursos d’água do parque Fernão Dias,
Contagem, MG
Margarete PEREIRA1, Madrith STHEL COSTA DUARTE1,
Adriel ANDRADE PALHARES1, Alexandre OLIVEIRA1,
Marcus Gustavo DELLA LUCIA1, Thiago MONTALVÃO1,
Tawan LACRISIO1 & Arthur BARBOSA DE PAULA1
1
Centro Universitario Una
Palabras claves: mapeamento, qualidade de águas, parque
Fernão Dias.
Parque Fernão Dias, localizado na divisa dos municípios
de Contagem e Betim possui uma considerável área de
vegetação com várias nascentes. Trata–se de uma área de 1,2
milhão de metros quadrados, coberta por vegetação nativa
secundária caracterizada como floresta estacional semidecidual
com vestígios de um antigo plantio de eucaliptus.sp com
mais de 30 anos de idade com sub–bosque nativo e espécies
invasoras. Não existe nenhum estudo sobre a área e visto a
importância ambiental que esta representa, objetivou–se neste
trabalho, a localização mapeamento e verificação da qualidade
da água de algumas nascentes do parque. O presente trabalho foi
realizado como atividade complementar na disciplina Projeto
Aplicado Qualidadade de Águas do Centro Universitário Una.
Inicialmente, foi realizado um modelo produzido com mapas
topográficos 1:25 000 e posterior sobreposição das curvas de
nível a imagens da vegetação obtidas pelo Google Earth e em
ortofoto do ano de 1982. O modelo foi testado em campo, alguns
dos cursos d’água não encontrados foram retirados. Forma
realizados ainda análise de amostras de água para análise de
O
229
Día 1 • Agosto 31
XIV Congreso Latinoamericano de Geología y XIII Congreso Colombiano de Geología