369 research outputs found
Mineralogía y geoquímica de las menas de óxidos de Fe-Ti en la anortosita de Don Dieguito, Sierra Nevada de Santa Marta, Colombia
Fe-Ti oxide ores are commonly associated
with Proterozoic massif-type
anorthosite bodies emplaced during the
Grenville orogeny (~1.2-1.0 Ga). Some
of these anorthositic bodies occur in the
northernmost part of the Santa Marta
Massif, Colombia. They locally contain
crosscutting Fe-Ti(-V) ore bodies between
the El Hierro creek and the Don Dieguito
river. We have distinguished two types
of Fe-Ti(-V) ores: i) oxide-apatite norite
(fine grained ilmenite and magnetite
disseminated in an assemblage of apatite,
amphibole, chlorite, rutile and sericitized
plagioclase) and ii) banded nelsonite
(coarser grained ilmenite, magnetite and
apatite distributed in bands, with minor
baddeleyite, srilankite and högbomite).
Ilmenite in the two ore types display
distinct hematite exsolution features: a)
needle-like in the oxide-apatite norite ore;
and b) two generations of exsolutions in
the banded ore. Magnetite shows similar
Ti and V contents in both ore types
(0.4 wt % TiO2 and 0.5 wt % V2O3 on
average in the oxide-apatite norite ore,
0.5 wt % TiO2 and 0.4 wt % V2O3 in the
banded ore), whereas ilmenite has higher
hematite, pyrophanite and geikielite
components in the banded ore. The ores
might have formed from the combination
of fractional crystallization and magma
mixing, with exsolution occurring probably
at 575-600°C. This first detailed mineralogical
and textural study of Fe-Ti(-V)
oxide ores in anorthosite massifs from
Colombia suggests that the Santa Marta
Massif is an interesting target for future
research.Las mineralizaciones de óxidos de Fe-Ti se
asocian comúnmente a complejos anortosíticos
proterozoicos (massif-type) emplazados durante la
orogenia Grenvilliana (~1.2-1.0 Ga). Algunos
de estos cuerpos anortosíticos se encuentran en la
parte septentrional del Macizo de Santa Marta,
en Colombia. Localmente, éstos contienen cuerpos
de óxidos de Fe-Ti(-V) entre la quebrada El
Hierro y el río Don Dieguito. Se han distinguido
dos tipos de mineralizaciones de Fe-Ti(-V): i)
norita con óxidos y apatito (ilmenita y magnetita
de grano fino diseminadas en una asociación
de apatito, anfíbol, clorita, rutilo y plagioclasa
sericitizada); y ii) nelsonita bandeada (ilmenita,
magnetita y apatito de grano grueso, distribuidos
en bandas, con cantidades menores de baddeleyita,
srilankita y högbomita). Las ilmenitas en los dos
tipos de mineralizaciones muestran diferentes
exsoluciones de hematites: con forma de aguja
en la mena diseminada; y dos generaciones de
exsoluciones en la mena bandeada. La magnetita
presenta contenidos en Ti y V similares en ambas
mineralizaciones (un promedio de 0.4 wt %
TiO2 y 0.5 wt % V2O3 en la diseminada, 0.5
wt % TiO2 y 0.4 wt % V2O3 en la bandeada),
mientras que la ilmenita tiene mayor componente
hematites, pirofanita y geikielita en la mena
bandeada. Las menas se podrían haber formado
por la combinación de cristalización fraccionada
y mezcla de magmas, y la exsolución tendría lugar
probablemente a 575-600°C. Esta primera
caracterización mineral y textural de los óxidos de
Fe-Ti(-V) en macizos anortosíticos en Colombia
indica que la Sierra de Santa Marta es un objetivo
interesante para investigaciones futuras
Review of Geochronologic and Geochemical Data of the Greater Antilles Volcanic Arc and Implications for the Evolution of Oceanic Arcs
The authors greatly appreciate Javier Escuder Viruete and two anonymous reviewers with many constructive suggestions that helped we improve the manuscript. Haoyu Hu acknowledges support by Federal State Funding at Kiel University while Yamirka Rojas-Agramonte acknowledges support by the Deutsche Forschungsgemeinschaft (DFG) grant RO4174/3-3 and Antonio GarciaCasco acknowledges support by the Agencia Estatal de Investigacion (AEI) grant MICINN PID2019-105625RB-C21. This is UTD Geosciences contribution #1682. Open access funding enabled and organized by Projekt DEAL.The Greater Antilles islands of Cuba, Hispaniola, Puerto Rico and Jamaica plus the Virgin
Islands host fragments of the fossil convergent margin that records Cretaceous subduction (operated for about
90 m.y.) of the American plates beneath the Caribbean plate and ensuing arc-continent collision in Late
Cretaceous-Eocene time. The “soft” collision between the Greater Antilles Arc (GAA) and the Bahamas
platform (and the margin of the Maya Block in western Cuba) preserved much of the convergent margin. This
fossil geosystem represents an excellent natural laboratory for studying the formation and evolution of an intraoceanic
convergent margin. We compiled geochronologic (664 ages) and geochemical data (more than 1,500
analyses) for GAA igneous and metamorphic rocks. The data was classified with a simple fourfold subdivision:
fore-arc mélange, fore-arc ophiolite, magmatic arc, and retro-arc to inspect the evolution of GAA through
its entire lifespan. The onset of subduction recorded by fore-arc units, together with the oldest magmatic arc
sequence shows that the GAA started in Early Cretaceous time and ceased in Paleogene time. The arc was
locally affected (retro-arc region in Hispaniola) by the Caribbean Large Igneous Province (CLIP) in Early
Cretaceous and strongly in Late Cretaceous time. Despite multiple biases in the database presented here, this
work is intended to help overcome some of the obstacles and motivate systematic study of the GAA. Our results
encourage exploration of offshore regions, especially in the east where the forearc is submerged. Offshore
explorations are also encouraged in the south, to investigate relations with the CLIP.Federal State Funding at Kiel UniversityGerman Research Foundation (DFG) RO4174/3-3Agencia Estatal de Investigacion (AEI) grant MICIN
Subduction Zones of the Caribbean : the sedimentary, magmatic, metamorphic and ore-deposit records UNESCO/iugs igcp Project 546 Subduction Zones of the Caribbean
The International Union of Geosciences (IUGS) and UNESCO IGCP project 546 Subduction Zones of the Caribbean (http://www.ugr.es/~agcasco/igcp546/) was launched in 2007 and scheduled to be completed by the end of the current year 2011. It was set up with the aim of gathering researchers interested in the geological evolution of the Caribbean realm. The development of this region is largely controlled by a number of subduction zones that formed along its margins from the break-up of Pangea during the Jurassic until Present. The current setting is characterized by a very complex plate-tectonic configuration dominated by subduction zones, large-scale strike-slip faults, volcanic arcs and collision belts (Figure 1). The project was built upon previous developments of IGCP project 433 Caribbean Plate Tectonics (2000-2005), of which the Special Volume 4 (Issue 1-2) of Geologica Acta Caribbean Plate Tectonics. Stratigraphic, Magmatic, Metamorphic and Tectonic Events (Iturralde Vinent and Lidiak, 2006) deserves mentioning
Multiple veining in a paleo–accretionary wedge: The metamorphic rock record of prograde dehydration and transient high porefluid pressures along the subduction interface (Western Series, central Chile)
Thaïs Hyppolito is acknowledged for sharing her knowledge
about local geology. Anne Verlaguet, Hugues Raimbourg, and
James Connolly are also acknowledged for insightful discussions on fluid-rock metamorphic processes. Ralf Halama
and two anonymous reviewers are warmly acknowledged for
insightful comments. Mauricio Calderón, Francisco Fuentes, and
the Earth Sciences department at Universidad Andrés Bello
(Santiago, Chile) are thanked for their technical assistance. A.C.
acknowledges the research grant provided by the Alexander
von Humboldt Foundation for a post-doctoral fellowship at
Ruhr-Universität Bochum.High pressure–low temperature metamorphic
rocks from the late Paleozoic accretionary wedge
exposed in central Chile (Pichilemu region) are
characterized by a greenschist-blueschist lithological association with interbedded metasediments
that reached peak burial conditions of ~400 °C
and 0.8 GPa during late Carboniferous times. We
herein combine new extensive field observations,
structural measurements, and geochemical and
petrological data on vein and matrix material from
Pichilemu transitional greenschist-blueschist facies
rocks. The studied veins were first filled by albite, followed by quartz and calcite as well as glaucophane
and winchite. Field, structural, and microscopic
zoning patterns show that these rocks underwent
a protracted sequence of prograde vein-opening
events, which have been largely transposed to the
main foliation before and during underplating in
the basal accretion site near 25–30 km depth. While
some of the earliest albite-filled vein sets may have
formed after prograde breakdown of sub–greenschist facies minerals (<250 °C), our thermodynamic
modeling shows that relatively minor amounts of
fluid are produced in the subducted pile by dehydration reactions between 250 and 400 °C along
the estimated geothermal gradient. It also confirms
that the formation of interlayered blueschist and
greenschist layers in Pichilemu metavolcanics is a
consequence of local bulk composition variations,
and that greenschists are generally not formed due
to selective exhumation-related retrogression of
blueschists. The early vein sets are a consequence
of prograde internal fluid production followed by
sets of hydrofractures formed at near-peak burial
that are interpreted as a record of external fluid
influx. We postulate that such a fractured sequence
represents a close analogue to the high-Vp/Vs
regions documented by seismological studies
within the base of the seismogenic zone in active
subduction settings.This work has been funded by an
Initiative D’EXcellence (IDEX) grant 16C538 to S.A. The University of Granada is acknowledged for partial funding. Part of this
work was also supported by the TelluS Program of CNRS/INSU.
This is Institut de Physique du Globe de Paris contribution 4124
Cinemática de los intervalos de la marcha utilizando kinovea en pacientes con artrosis de rodilla
La alteración de la marcha en el adulto se considera un predictor de deterioro funcional. El objetivo principal del estudio se basó en la evaluación de la cinemática de los intervalos de la marcha utilizando el programa kinovea en pacientes adultos con diagnóstico de artrosis de rodilla en el área de fisioterapia del Centro de Salud Familiar Leonel Rugama, Estelí. El diseño metodológico se enmarco en un estudio observacional descriptivo de estudio de caso
con enfoque cuantitativo, conformado por 9 sujetos que cumplen los criterios de inclusión previamente establecidos. Se estableció la encuesta para la recolección de datos que
comprende información básica del paciente. Por medio de la revisión documental, se revisaron los expedientes clínicos para obtener los grados de artrosis de los pacientes. Asi
mismo a traves de una guia de observación directa la cual fue útil para identificar los parámetros espaciotemporales e intervalos de la cinemática de la marcha. Entre los resultados destacan: Predominio del sexo femenino, entre las edades de 55 a 59 años, resaltando la obesidad en clase 1 con los grados 2 y 3 de artrosis, siendo la hipertensión arterial la principal enfermedad común. Resultó predominante la velocidad rápida, longitud de zancada y de paso mínima en los parámetros espaciotemporales. Las limitaciones de la cinemática de los intervalos de la marcha en pacientes con artrosis de rodilla estuvieron afectadas en los intervalos 1, 2 y 3 de tobillo, rodilla y cadera. Palabras Claves: Artrosis, Marcha, Cinemática, Kinovea, Evaluació
Ultramafic-hosted volcanogenic massive sulfide deposits from Cuban ophiolites
Ultramafic-hosted volcanogenic massive sulfide deposits (UM-VMS) located in the Havana-Matanzas ophiolite
(Cuba) are the only known example of this type of mineralization in the Caribbean realm. UM-VMS from Havana-
Matanzas are enriched in Cu, Ni, Co, Au, and Ag. The mineralization consists of massive sulfide bodies mostly
composed of pyrrhotite and hosted by serpentinized upper mantle peridotites. Chemical composition of unaltered
cores in Cr-spinel grains found within the massive sulfide mineralization and in the peridotite host indicates
formation in the fore-arc region of the Greater Antilles volcanic arc. A first stage of serpentinization probably
took place prior to the sulfide mineralization event. The UM-VMS mineralization formed by the near-complete
replacement of the silicate assemblage of partially serpentinized peridotites underneath the seafloor. The
sequence of sulfide mineralization has been divided into two stages. The first stage is characterized by a very
reduced hydrothermal mineral assemblage consisting of pyrrhotite, Co–Ni–Fe diarsenides, chalcopyrite, Co-rich
pentlandite, and electrum. In the second stage, pyrite and Co–Ni–Fe sulfarsenides partially replaced pyrrhotite
and diarsenides, respectively, under a more oxidizing regime during the advanced stages of ongoing serpentinization.
The proposed conceptual genetic model presented here can be useful for future exploration targeting
this type of deposit in the Caribbean region and elsewhere.Spanish Government PI0975CAP Investigacion PUCP-2022 Program PID 2019- 105625RB-C21MCIN/AEI PRE 2020-092140
2022-A- 004
A track record of Au–Ag nanomelt generation during fluid‑mineral interactions
This research was financially supported by Grant PID 2019-105625RB-C21 funded by MCIN/AEI/10.13039/501100011033, by Grant 2021 SGR 00239 funded by Gestió d’Ajuts Universitaris i de Recerca de
Catalunya. Additional funding was provided by a “Ayudas predoctorales 2020” number PRE 2020-092140 PhD
grant to DD-C by the Spanish Ministry of Science and Innovation and the Proyecto de Excelencia de la Junta
de Andalucía (Spain), PROYECTEXCEL_00705 to JMGJ. Laura Casado (Instituto de Nanociencia de Aragón
(INA)—University of Zaragoza) and María del Mar Abad (CIC, University of Granada) are acknowledged for her
assistance with FIB and HRTEM respectivelyThe online version contains supplementary material available at https:// doi. org/
10. 1038/ s41598- 023- 35066-yRecent studies have reported the significant role of Au-bearing nanoparticles in the formation of hydrothermal gold deposits. Despite the ever-increasing understanding of the genesis and stability of Au-bearing nanoparticles, it is still unknown how they behave when exposed to hydrothermal fluids. Here, we study the nanostructural evolution of Au–Ag nanoparticles hosted within Co-rich diarsenides and sulfarsenides of a natural hydrothermal deposit. We use high-resolution transmission electron microscopy to provide a singular glimpse of the complete melting sequence of Au–Ag nanoparticles exposed to the hydrothermal fluid during coupled dissolution–precipitation reactions of their host minerals. The interaction of Au–Ag nanoparticles with hydrothermal fluids at temperatures (400–500 ºC) common to most hydrothermal gold deposits may promote melting and generation of Au–Ag nanomelts. This process has important implications in noble metal remobilization and accumulation during the formation of these deposits.MCIN/AEI/10.13039/501100011033, PID 2019-105625RB-C21Gestió d'Ajuts Universitaris i de Recerca de
Catalunya 2021 SGR 00239Ministerio de Ciencia e Innovación PRE 2020-092140 PhDProyecto de Excelencia de la Junta de Andalucía
PROYECTEXCEL_00705Instituto de Nanociencia de Aragón
(INA)-Universidad de ZaragozaComisión de Investigaciones Científicas (CIC), Universidad de Granad
Vetas de cromitita en ortopiroxenita anómalamente enriquecidas en minerales del grupo del platino de la ofiolita Habana-Matanzas, Cuba
The Havana–Matanzas Ophiolite contains
one of the few examples of ophiolitic platinum
group minerals (PGM)-rich chromitites
associated with orthopyroxenites in the
mantle section of ophiolitic complexes. The
chromitites occur as veins hosted by orthopyroxenite
bands within mantle peridotites.
The peridotites are mostly harzburgites
and their accessory chromite shows high-Al
compositions (Cr# [Cr/(Cr+Al), atomic
ratio] = 0.39–0.50), which are typical of
spinels in abyssal peridotites. Conversely,
chromite from the chromitite veins and
their host orthopyroxenite are high-Cr (Cr#
= 0.72–0.73 and 0.62–0.69, respectively),
with lower Mg# [Mg/(Mg+Fe2+), atomic
ratio]. This suggests that both the chromitite
and the orthopyroxenite formed from
melts with boninitic affinity. The abundant
PGM inclusions found in the chromitites are
mainly Os-rich laurite grains, which is also
characteristic of chromitites formed from
magmas with boninitic affinity. Therefore,
we propose that the chromitite veins and
the orthopyroxenite bands probably formed
contemporaneously in the fore-arc setting
of an intra-oceanic arc during subduction.
The chromitite-orthopyroxenite pair of the
Havana-Matanzas Ophiolite could form
after the reaction of a Si-rich melt with
boninitic affinity and mantle harzburgite,
with the orthopyroxenite bands preserving
fingerprints of the infiltration of boninitic-
affinity melts within the mantle. The
small volume of forming chromitite could
maximize the efficiency for the mechanical
collection of the PGM forming in the
parental melt of these rocks, resulting in the
anomalous enrichment of primary PGM in
the chromitites.La ofiolita de Habana-Matanzas contiene uno de
los pocos ejemplos de cromititas ricas en minerales
del grupo del platino (MGP) asociadas a ortopiroxenitas
de la sección mantélica de complejos ofiolíticos.
Las cromititas ocurren como venas encajadas en
bandas de ortopiroxenita dentro de la peridotita
mantélica. Las peridotitas son mayoritariamente
harzburgitas con cromita accesoria rica en Al (#Cr
[Cr/(Cr+Al), cociente atómico] = 0.39–0.50),
lo cual es típico de espinelas en peridotitas abisales.
Por otro lado, la cromita perteneciente a las venas
de cromitita y a la ortopiroxenita encajante es rica
en Cr (#Cr = 0.72–0.73 y 0.62–0.69, respectivamente)
y con bajo #Mg [Mg/(Mg+Fe2+),
cociente atómico]. Esto sugiere que tanto las venas de
cromitita como la ortopiroxenita se formaron a partir
de fundidos de afinidad boninítica. Las abundantes
inclusiones de MGP encontradas en las cromititas
son principalmente granos de laurita ricos en Os, lo
cual también es propio de cromititas formadas a partir
de magmas con afinidad boninítica. Por lo tanto,
proponemos que las venas de cromitita y las bandas
de ortopiroxenitas se formaron contemporáneamente
en un contexto de ante-arco en un arco intra-oceánico
durante el proceso de subducción. El conjunto
cromitita-ortopiroxenita de la ofiolita de Habana-
Matanzas se formó por la reacción de fundidos
ricos en Si con afinidad boninítica y la harzburgita
mantélica. Las bandas de ortopiroxenitas sería la
huella química que habrían dejado estos fundidos
boniníticos al infiltrarse por el manto. El volumen
reducido de las cromititas que se formaron maximizó
la eficiencia del proceso de recolección mecánica de
los MGP que se formaban en el fundido parental,
dando lugar al enriquecimiento de MGP primarios
como inclusiones en las cromititas
Zircon Dates Long-Lived Plume Dynamics in Oceanic Islands
In this contribution we report the first systematic study of zircon U-Pb geochronology and
δ 18O-εHf(t) isotope geochemistry from 10 islands of the hot-spot related Galapagos Archipelago. The data
extracted from the zircons allow them to be grouped into three types: (a) young zircons (0–∼4 Ma) with εHf(t)
(∼5–13) and δ 18O (∼4–7) isotopic mantle signature with crystallization ages dating the islands, (b) zircons
with εHf(t) (∼5–13) and δ 18O (∼5–7) isotopic mantle signature (∼4–164 Ma) which are interpreted to date
the time of plume activity below the islands (∼164 Ma is the minimum time of impingement of the plume
below the lithosphere), and (c) very old zircons (∼213–3,000 Ma) with mostly continental (but also juvenile)
εHf(t) (∼−28–8) and δ 18O (∼5–11) isotopic values documenting potential contamination from a number of
sources. The first two types with similar isotopic mantle signature define what we call the Galápagos Plume
Array (GPA). Given lithospheric plate motion, this result implies that GPA zircon predating the Galápagos
lithosphere (i.e., >14–164 Ma) formed and were stored at sublithospheric depths for extended periods of time.
In order to explain these observations, we performed 2D and 3D thermo-mechanical numerical experiments of
plume-lithosphere interaction which show that dynamic plume activity gives rise to complex asthenospheric
flow patterns and results in distinct long-lasting mantle domains beneath a moving lithosphere. This
demonstrates that it is physically plausible that old plume-derived zircons survive at asthenospheric depths
below ocean islands.German Research Foundation (DFG) RO4174/3-1
RO4174/3-3Ministry of Science and Innovation, Spain (MICINN)Spanish GovernmentEuropean Commission PID2019-105625RB-C21
PY20_00550European Research Council (ERC)
European Commission MAGMA 77114
Limited genetic antagonism between premium cuts yield and intramuscular fat content in Iberian pigs
Ponencia publicada en ITEA, vol.104La producción de cerdo ibérico está orientada a la obtención de materia prima para la elaboración de productos curados de alta calidad, determinada entre otros factores por el contenido en grasa intramuscular. Este trabajo tiene como objetivo estimar las correlaciones genéticas entre el contenido de grasa intramuscular, medido mediante tecnología NIRS en M. longissimus, y los principales caracteres productivos: porcentaje de jamones, paletas y lomos del peso de la canal, y la ganancia media diaria durante el periodo de ‘Montanera’. Los registros analizados proceden de 6.103 cerdos castrados de 56 ganaderías y controlados desde 1993 al 2007 por AECERIBER. Los animales con un manejo extensivo común fueron sacrificados, en 79 lotes, a un peso medio de aproximadamente 160 kg. Las heredabilidades estimadas presentaron valores altos para todos los caracteres (0,37 a 0,48) indicando que la selección para todos los caracteres puede ser efectiva. Las correlaciones genéticas entre el porcentaje de las principales piezas nobles fueron altas y positivas (de 0,36 a 0,69) lo cual indica que dichos caracteres están en parte controlados por un mismo grupo de genes. Las correlaciones genéticas entre el contenido en grasa intramuscular y ganancia media diaria y el porcentaje de paletas no fueron significativamente diferentes de cero. Sin embargo, se estimaron efectos negativos significativos entre el contenido en grasa intramuscular y el porcentaje de jamones (-0.19 ± 0.04) y lomos (-0.23 ± 0.03). Estos valores indican que una intensa selección orientada a mejorar el porcentaje de piezas nobles de la canal, puede a medio plazo deteriorar la calidad de los productos curados en cerdos Ibéricos.The production of Iberian pigs is mainly focused to obtain raw meat to elaborate dry-cured products of high sensorial quality, mainly influenced by the intramuscular fat content. The objective of this work was to estimate the genetic correlations between intramuscular fat content in M. longissimus, measured using NIRS technology, and the main productive traits: percentages on carcass weight of hams, forelegs and loins, and the daily growth along the final fattening period. Records for this analysis came from 6,103 castrate males, born in 56 herds and controlled by AECERIBER from 1993 to 2007. All the animals were fattened with a common extensive management system and slaughtered, distributed in 79 batches, at approximately 160 kg. Heritability estimates presented high values for all the traits (ranging between 0.37 and 0.48) indicating that the selection for these traits could be effective. Genetic correlations between percentages of premium cuts were high and positive (from 0.36 to 0.69). This fact indicates that these traits are partially controlled by the same group of genes. Genetic correlations between intramuscular fat content and the daily growth and percentage of forelegs showed estimated values statistically non different from cero. However, significant negative values of genetic correlations were estimated between intramuscular fat content and the percentages of hams (-0.19 ± 0.04) and loins (-0.23 ± 0.03). These last values indicate that a strong selection in Iberian pigs focused to the improvement of the carcass percentage of premium cuts, could cause a deterioration of the meat suitability for dry-curing in a medium-time horizon
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