scholarly journals The Poopó Polymetallic Epithermal Deposit, Bolivia: Mineralogy, Genetic Constraints, and Distribution of Critical Elements

Minerals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 472 ◽  
Author(s):  
Torres ◽  
Melgarejo ◽  
Torró ◽  
Camprubí ◽  
Castillo-Oliver ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Mineral Chemistry ◽  
Epithermal Deposit ◽  
Genetic Constraints ◽  
Epithermal Deposits ◽  
Critical Elements ◽  
The Family ◽  
Tin Deposits ◽  
Bolivian Altiplano ◽  
Low Sulfidation

The tin-rich polymetallic epithermal deposit of Poopó, of plausible Late Miocene age, is part of the Bolivian Tin Belt. As an epithermal low sulfidation mineralisation, it represents a typological end-member within the “family” of Bolivian tin deposits. The emplacement of the mineralisation was controlled by the regional fault zone that constitutes the geological border between the Bolivian Altiplano and the Eastern Andes Cordillera. In addition to Sn and Ag, its economic interest resides in its potential in critical elements as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Poopó deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring to ascertain plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. The poor development of hydrothermal alteration assemblage, the abundance of sulphosalts and the replacement of löllingite and pyrrhotite by arsenopyrite and pyrite, respectively, indicate that this deposit is ascribed to the low-sulphidation subtype of epithermal deposits, with excursions into higher states of sulphidation. Additionally, the occurrence of pyrophyllite and topaz has been interpreted as the result of discrete pulses of high-sulphidation magmatic fluids. The δ34SVCDT range in sulphides (−5.9 to −2.8‰) is compatible either with: i. hybrid sulphur sources (i.e., magmatic and sedimentary or metasedimentary); or ii. a sole magmatic source involving magmas that derived from partial melting of sedimentary rocks or underwent crustal assimilation. In their overall contents in critical elements (In, Ga and Ge), the key minerals in the Poopó deposit, based on their abundance in the deposit and compositions, are rhodostannite, franckeite, cassiterite, stannite and, less importantly, teallite, sphalerite and jamesonite.

scholarly journals Mineralogy and Distribution of Critical Elements in the Sn–W–Pb–Ag–Zn Huanuni Deposit, Bolivia

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 753 ◽  
Author(s):  
Andreu Cacho ◽  
Joan-Carles Melgarejo ◽  
Antoni Camprubí ◽  
Lisard Torró ◽  
Montgarri Castillo-Oliver ◽  
...  
Keyword(s):  
Methodological Approach ◽  
Central Area ◽  
Mineral Chemistry ◽  
Potassium Feldspar ◽  
Critical Elements ◽  
Differential Reactivity ◽  
Argillic Alteration ◽  
Peripheral Areas ◽  
Tin Deposit ◽  
Host Rocks

The polymetallic Huanuni deposit, a world-class tin deposit, is part of the Bolivian tin belt. As a likely case for a “mesothermal” or transitional deposit between epithermal and porphyry Sn types (or shallow porphyry Sn), it represents a case that contributes significantly to the systematic study of the distribution of critical elements within the “family” of Bolivian tin deposits. In addition to Sn, Zn and Ag, further economic interest in the area resides in its potential in critical elements such as In, Ga and Ge. This paper provides the first systematic characterisation of the complex mineralogy and mineral chemistry of the Huanuni deposit with the twofold aim of identifying the mineral carriers of critical elements and endeavouring plausible metallogenic processes for the formation of this deposit, by means of a multi-methodological approach. With In concentrations consistently over 2000 ppm, the highest potential for relevant concentrations in this metal resides in widespread tin minerals (cassiterite and stannite) and sphalerite. Hypogene alteration assemblages are hardly developed due to the metasedimentary nature of host rocks, but the occurrence of potassium feldspar, schorl, pyrophyllite and dickite as vein material stand for potassic to phyllic or advanced argillic alteration assemblages and relatively high-temperature (and low pH) mineralising fluids. District-scale mineralogical zonation suggests a thermal zonation with decreasing temperatures from the central to the peripheral areas. A district-scale zonation has been also determined for δ34SVCDT values, which range −7.2‰ to 0.2‰ (mostly −7‰ to −5‰) in the central area and −4.2‰ to 1.0‰ (mainly constrained between −2‰ and 1‰) in peripheral areas. Such values stand for magmatic and metasedimentary sources for sulfur, and their spatial zoning may be related to differential reactivity between mineralising fluids and host rocks, outwardly decreasing from the central to the peripheral areas.

scholarly journals A portrait of Italian ‘Family houses’: diversified heritage in a redefined territorial and demographic context

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Federico Zanfi ◽  
Chiara Merlini ◽  
Viviana Giavarini ◽  
Fabio Manfredini
Keyword(s):  
Demographic Change ◽  
Demographic Transition ◽  
Methodological Approach ◽  
Property Values ◽  
Italian Family ◽  
The Family ◽  
The Subject ◽  
The 1960S ◽  
Demographic Context ◽  
Family House

AbstractThe ‘family house’ has played a major role within the urbanisation processes that have been transforming the Italian landscape since the 1960s. It is a common feature of the widespread settlements that are part of what has been labelled the ‘diffuse city’ and was the subject of numerous studies during the 1990s. More than 20 years later, this paper returns to the topic of the Italian family house using a renewed methodological approach to describe relevant changes. The hypothesis here is that in order to grasp the tensions affecting ‘family houses’ in today’s context of demographic transition and increased imbalances between dynamic and declining areas, and to contemplate their future, the qualitative gaze adopted by scholars in the 1990s must be integrated with other investigative tools, focusing on demographic change, uses, and the property values of buildings. Using this perspective, the paper provides a series of ‘portraits’ rooted in four meaningful territorial contexts, portraits which may help scholars to redefine their imagery associated with family house and be useful for dedicated building policies.

scholarly journals ATENDIMENTO EDUCACIONAL ESPECIALIZADO NA MODALIDADE DOMICILIAR: um estudo de caso

2015 ◽  
Vol 22 (3) ◽  
pp. 59
Author(s):  
Annie Gomes Redig
Keyword(s):  
Methodological Approach ◽  
Motor Impairment ◽  
Educational Services ◽  
Teacher Formation ◽  
Material Resources ◽  
Multiple Disability ◽  
The Family ◽  
Final Consideration ◽  
Investigación Cualitativa

O presente trabalho tem como objetivo analisar o Atendimento Educacional Especializado, na modalidade domiciliar, considerando seu funcionamento, organização, formação do professor e impacto sobre a dinâmica familiar. Neste estudo adotou-se a pesquisa qualitativa, e como metodologia o estudo de caso e no desenvolvimento dos atendimentos pedagógicos domiciliares, foram adotados os pressupostos da pesquisa-ação. O estudo teve como participante uma aluna de 12 anos com deficiência múltipla, envolvendo as áreas cognitiva e motora. Esse estudo se desenvolveu durante o período compreendido de 2013-2015 e o acompanhamento variou de uma a duas vezes por semana. Observou-se que o Atendimento Educacional Especializado, na modalidade domiciliar, beneficiou tanto o desenvolvimento da aluna quanto auxiliou a família a entender o processo de ensino-aprendizagem. Nas considerações finais destaca-se a necessidade de uma formação/ capacitação mais específica para os professores atuantes nessa modalidade de atendimento educacional, além de recursos pedagógicos e materiais disponíveis para o ensino domiciliar.Palavras-chave: Atendimento educacional especializado. Deficiência múltipla. Formação docente. SPECIALIZED EDUCATIONAL SERVICES AT HOME: a case studyAbstract: The present paper has the objective to reflect about the specialized educational attendance at domiciliarymode, and analyze its operation, organization, teacher formation and impact of this service on family routine.For this research a qualitative research was used, and as methodological approach, the case study and for thedeveloping of home teaching visits we used the assumptions of the action research. The study had participation ofone student with 12 years old with severe cognitive and motor impairment. This study had the duration of 2 years(2013-2015) and the accompaniment was once or twice a week. Therefore it is concluded that the teaching servicewas beneficial to the students development and also helped the family to understand the process of study of theirdaughter. As final consideration we see a need of a more specific formation for the teachers of this modality and theaddition of material resources for teaching at the specialized educational attendance at domiciliary mode.Keywords: Specialized educational services. Multiple disability. Teacher formation.   SERVICIO EDUCATIVO ESPECIALIZADO EN MODO EN EL HOGAR: un estudiode casoResumen: El presente trabajo tiene como objetivo analizar el Atendimiento Educacional, en la modalidad residencial,teniendo en cuenta su funcionamiento, la organización, la formación del profesorado y sus impactos en la rutinafamiliar. En este estudio Para este trabajo, se utilizó la investigación cualitativa, como metodología el estudio decaso y en el desarrollo de los atendimientos pedagógicos domiciliarias, se adoptó el requisito de la investigación-acción.El estudio tuve como participantes una alumna de 12 años con discapacidades múltiples, involucrando áreascognitivas y motoras. Este estudio fue desarrollado por dos años (2013-2015) y el acompañamiento varió de una ados veces a la semana. Se observó que el Atendimiento Educacional Especializado, en la modalidad domiciliaria,benefició tanto en el desarrollo de la alumna, cuanto auxilió a la familia a entender el proceso de enseñanza-aprendizaje.En las consideraciones finales se destaca la necesidad de una formación/capacitación más específica paralos profesores que trabajan en este tipo específico de modalidad educacional, además de los recursos pedagógicosy materiales disponibles para la enseñanza domiciliaria.Palabras clave: Atendimiento Educacional Especializado. Discapacidades múltiples. Formación del profesorado.

Revisiting the Study of Family Businesses: Methodological Challenges, Dilemmas, and Alternative Approaches

1998 ◽  
Vol 11 (3) ◽  
pp. 239-252 ◽  
Author(s):  
Mary Winter ◽  
Margaret A. Fitzgerald ◽  
Ramona K. Z. Heck ◽  
George W. Haynes ◽  
Sharon M. Danes
Keyword(s):  
Empirical Evidence ◽  
Family Business ◽  
Methodological Approach ◽  
Family Businesses ◽  
Business Research ◽  
Internal Dynamics ◽  
Methodological Challenges ◽  
The Family ◽  
Alternative Approaches ◽  
Social Units

Family businesses are vital but understudied economic and social units. Previous family business research is limited relative to its definitions, sampling, and resulting empirical evidence. This paper presents an alternative methodological approach to the study of family businesses with the potential for allowing multiperspective and detailed analyses of the nature and internal dynamics of both the family and the business and the interaction between the two.

Paragenesis and mineral chemistry of alabandite (MnS) from the Ag-rich Santo Toribio epithermal deposit, Northern Peru

2003 ◽  
Vol 67 (1) ◽  
pp. 95-102 ◽  
Author(s):  
G. R. Olivo ◽  
K. Gibbs
Keyword(s):  
High Salinity ◽  
Early Stage ◽  
Mineral Chemistry ◽  
Abrupt Decrease ◽  
Epithermal Deposits ◽  
Second Stage ◽  
The World ◽  
Northern Peru ◽  
World Class ◽  
Polymetallic Ore

AbstractThe Miocene, epithermal, Ag-rich polymetallic Santo Toribio deposit is hosted by the volcanics of the Quiruvilva-Pierina subbelt, Northern Peru, which also comprises the world-class, high sulphidation Pierina deposit. The Ag-rich, alabandite-bearing veins of the Santo Toribio deposit formed during two major stages. The early stage is characterized by deposition of arsenopyrite, pyrite, quartz, Mn- sphalerite, stannite, alabandite and minor miargyrite. Sphalerite associated with this stage is exceptionally enriched in Mn (up to 14.5 wt.%) and alabandite is optically and mineralogically zoned. Its brown zones have greater Fe+Sb and smaller Mn contents than the green zones and Fe+Sb replaces Mn in its structure. During this early stage, fs2 must have been high to allow the stabilization of alabandite relative to rhodochrosite. In the second stage, the physicochemical conditions changed and the CO2/S ratio increased, causing dissolution of alabandite and the deposition of abundant rhodochrosite and a second generation of arsenopyrite, pyrite and quartz, sphalerite with chalcopyrite inclusions, mirargyrite, ramdohrite, and finally stibnite. This polymetallic ore probably formed due to an abrupt decrease in H+ and/or Cl- concentration caused by boiling or dilution of the high-salinity hydrothermal fluids and constitutes an example of “intermediate sulfidation-state” epithermal deposits.

scholarly journals Textural Characteristics of Noncrystalline Silica in Sinters and Quartz Veins: Implications for the Formation of Bonanza Veins in Low-Sulfidation Epithermal Deposits

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 331 ◽  
Author(s):  
Tadsuda Taksavasu ◽  
Thomas Monecke ◽  
T. Reynolds
Keyword(s):  
Power Plant ◽  
Precious Metal ◽  
Precious Metals ◽  
Fused Silica ◽  
Silica Microspheres ◽  
Textural Characteristics ◽  
Epithermal Deposits ◽  
Ore Minerals ◽  
Low Sulfidation ◽  
Ore Deposition

Silica sinters forming at the Wairakei geothermal power plant in New Zealand are composed of noncrystalline opal-A that deposited rapidly from cooling geothermal liquids flashed to atmosphere. The sinter is laminated with alternating layers of variably compacted silicified filamentous microbes encased by chains of fused silica microspheres. Microscopic inspection of bonanza quartz vein samples from the Buckskin National low-sulfidation epithermal precious metal deposit in Nevada showed that colloform bands in these veins exhibit relic microsphere textures similar to those observed in the silica sinters from the Wairakei power plant. The textural similarity suggests that the colloform bands were originally composed of noncrystalline opal-A that subsequently recrystallized to quartz. The colloform bands contain dendrites of electrum and naumannite that must have grown in a yielding matrix of silica microspheres deposited at the same time as the ore minerals, implying that the noncrystalline silica exhibited a gel-like behavior. Quartz bands having other textural characteristics in the crustiform veins lack ore minerals. This suggests that ore deposition and the formation of the colloform bands originally composed of compacted microspheres of noncrystalline silica are genetically linked and that ore deposition within the bonanza veins was only episodic. Supersaturation of silica and precious metals leading to the formation of the colloform bands may have occurred in response to transient flashing of the hydrothermal liquids. Flashing of geothermal liquids may thus represent a key mechanism in the formation of bonanza precious metal grades in low-sulfidation epithermal deposits.

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