Fig 10 - uploaded by Nora Rubinstein
Content may be subject to copyright.
Source publication
Las mineralizaciones vinculadas con sistemas de fallas extensionales en ambiente continental han sido reconocidas como tales recientemente, e individualizadas con modelos genéticos propios, ya que en el pasado no habían sido diferenciadas de otras mineralizaciones epitermales. Un grupo de depósitos ha sido agrupado por el Servicio Geológico de Esta...
Context in source publication
Context 1
... (2011) realizó un exhaustivo análisis del distrito y de él se sintetiza la información que sigue. El área comprende esencialmente dos grupos de vetas polimetálicas y una serie de vetas de cuarzo y de baritina asociadas ( fig. 10). La paragénesis está constituida por galena, pirita, calcopirita, fahlore rico en cinc, calcosina, niquelina, gersdorffita, gersdorffita cobaltífera, ullmanita, pechblenda, calcosina, bornita, digenita y millerita. La ganga consiste en ankerita, dolomita, siderita, baritina y escaso cuarzo. Las determinaciones de inclusiones fluidas ...
Similar publications
El presente documento pretende presentar una visión general sobre la Región de Los Santos (específicamente los cantones de Tarrazú, Dota y León Cortes) desde el punto de vista económico, institucional y ambiental; todos estos aspectos en relación al cultivo del café, el cual es el cultivo predominante en la región.
El objetivo de este cuaderno de t...
En el presente trabajo se hace una interpretación de las condiciones de meteorización y del marco tectónico del área fuente de las rocas siliciclásticas de la Formación Morita (Cretácico Inferior) a partir de datos de geoquímica de óxidos mayores obtenidos en muestras colectadas de sus columnas de la Sierra Anibacachi y el área de Rancho Búfalo, en...
La cripta situada bajo la sala capitular de la catedral de Mallorca, Figura 1, ha estado apeada durante varios decenios (quizá desde los años 1950 o 1960). Se trata de una bóveda de arista rebajada. Posibles razones para el apeo son los desconchones y daños que se observan en la parte baja de las aristas, las grietas en la zona cercana a la clave y...
Citations
... ej., Gregori et al., 2003). Derivación cortical (eHf -5.6 a -5.4: este trabajo; eNd -5.6: Pankhurst et al., 2006 Ulteriormente, esta dirección pudo haber actuado como anisotropía condicionante de los desplazamientos transcurrentes oblicuos a las cuencas de rift del Cretácico Inferior ubicadas en el deslinde Pampia-cratón del Río de la Plata (Uliana et al., 1989;Zappettini et al., 2015), como ocurre por ejemplo en las cuencas de General Lavalle y Macachín, particionadas en pequeños depocentros desplazados por fallas transcurrentes con dirección ~NO-SE (p. ej., Webster et al., 2004;de Elorriaga, 2010). ...
A study and review of the magmatic units that make up the Permian- Triassic Intracratonic Magmatic Corridor of La Pampa (CMPT-LP), south-central Argentina, has been carried out. New U-Pb SHRIMP ages, Hf isotopic composition, and chemical composition of some units of the CMPT-LP have been obtained, i.e. 1) Chacharramendi Syenogranite, age 254.7 ± 1.3 Ma (Late Permian, Lopingian), Hf model age of 1640 Ma with εHf average of -5.68; 2) Lihue Calel Rhyolite, 239.3 ± 1.5 Ma (Middle Triassic), Hf model age of 1640 Ma with εHf average -5.56. This indicates that the two dated units were crystallized from a mantle-derived melt that incorporated crust of late Statherian up to Calymmian age, taking also into account a Nd model age of 1483 Ma for the more distal (southeasternmost) sector (López Lecube Granite) of the CMPT-LP obtained by other authors. New geochemical data reported here, analyzed together with previous geochemical data, denote the anorogenic signature -intraplate environment- of the CMPT-LP magmatic corridor, highlighting its consistency with A1-type granites due to the similarity of their sources with those from which the oceanic island basalts (OIB) derive, as evidenced, e.g., by Y/Nb ratios <1.2. The classification of the rocks of the CMPT-LP mainly within the high potassium type is also consistent with its occurrence in an intraplate tectonic environment. The magmatism in the CMPT-LP has been considered as part of the Choiyoi Group, which is also related to late Permian to Early Triassic extension. Nevertheless, there is a marked contrast between the anorogenic environment of the CMPT-LP and the orogenic context of the Choiyoi Magmatic Arc. For this reason, the convenience of excluding the CMPT-LP from the Choiyoi Group is analyzed. In addition, the tectonic frames of the orogenic belts adjoining the CMPT-LP -San Rafael (or Sanrafaelic, or Choiyoi Arc-retroarc) and Northpatagonian Gondwanide belts- are compared briefly.
... Fluid circulation was controlled by pressure and tempera- ture gradients in the initial stage of the graben formation and ceased due to tectonic inversion ( Kríbek et al., 2009). Other examples include Champagne, France (Johan et al., 1982); Otish Mountains, Canada (Johan et al., 1987); Kitka River Valley, Finland (Vuorelaine et al., 1964); Santa Brigida, Argentina (Brodtkorb, 1999); and Talampaya, Argentina ( Zappettini et al., 2015). ...
... The Talampaya deposit includes 9 veins with predominantly NW-SE and subordinate NS strikes and hosted in Ordovician- Silurian granites. They mainly consist of barite and fluorite with minor Se and Cu minerals including umangite, klockmannite and clausthalite ( Zappettini et al., 2015). Although there are not stratigraphic or isotopic constrains for the age of these deposits, they are preliminarly included within this model based on their mineralogy. ...
... New field work and petrological data reveal that this mineralization is also hosted in Middle to Upper Triassic alkaline hypabyssal gabbros that intrude the Ordovician metamorphic rocks. Besides, the RREE pattern of the ore samples is very similar to that of the gabbros, thus suggesting a common source for the magmatism and the mineralizing fluids which allows assigning a Triassic age to these Se deposits ( Zappettini et al., 2015). ...
Mineral systems associated with extensional fault systems in continental environments and not related to magmatic activity involve various deposit models that can be grouped into a single system which would plausibly explain the source and chemical composition of fluids, the formation depth, the source of heat and the structural history within a common geologic setting.
Mineral deposits related to this tectonic setting are those described within the detachment-related model, including massive replacements, stockworks and veins of Cu and Fe oxides (with or without Au), polymetallic sulfide veins, barite and/or fluorite veins and stratabound and vein Mn deposits. This paper reviews the abovementioned deposits as well as others related to this tectonic setting, such as Se-rich polymetallic deposits, Almadén type Hg deposits, U-Ni-Co-As-Ag polymetallic deposits with subordinated Bi-Cu-Pb-Zn (five element deposits), simple polymetallic Pb-Ag-Zn deposits, and the members of the IOCG clan (including the Au-Ag detachment-related deposits) involved in the Cu-Fe (-Au) model deposits.
All these mineral deposits are the result of fluid motion unrelated to magmatism in areas of thermal anomalies. These fluids collect certain elements producing a district mineralogical specialization with inhomogeneities in the distribution of mineralization types along the region affected by rifting. Fluid homogenization temperatures and salinities range between 60° and 430 °C, and 0 and 27 equivalent wt% NaCl, respectively. The O, S and D isotope composition is consistent with basinal poral fluids derived from meteoric waters under different P-T conditions in an active faults environment. Pb isotopes suggest that Pb derives from a mixture of rocks with a long period of residence in the upper crust and rocks deformed along repeated orogenic cycles with a contribution of Pb from the lower crust and even the mantle. Fluid flow along fault planes leads to different types of hydrothermal alterations depending on P-T conditions, particularly propylitization and low temperature potassium metasomatism.
All such deposits can be found in two different geotectonic environments of metallogenic interest involving extensional faults associated with detachment zones in depth; i.e., 1) continental extension in a back-arc environment and 2) extension with rift development and generation of oceanic crust in a passive continental margin. Although the economic importance of this group of deposits is mainly related to industrial minerals, non-magmatic IOCG deposits could significantly augment the economic potential of this setting. The rift setting itself, without relation to detachments, is favorable for concentrating metals in stratabound deposits such as SEDEX ores. Additionally, the development of deposits directly related to magmatic activity contributes to the economic interest of this environment.