Una aproximación química a la clasificación modal QAPF y normativa Q' (F')-ANOR de las rocas ígneas, basada en su contenido en SiO2, CaO y K2O

Los magmas pueden dar origen a rocas plutónicas o volcánicas de la misma composición química. La composición modal de las rocas plutónicas puede ser cuantificada pero en el caso de las rocas volcánicas no suele ser posible por su textura afanítica y presencia de vidrio. Estas características impiden una clasificación mineralógica en diagramas equivalentes para ambos tipos de rocas. La IUGS recomienda el uso del diagrama químico TAS en los casos en que la obtención de la composición modal no sea posible, tratando de ajustar su nomenclatura a la del diagrama modal QAPF. Una mejor aproximación se consigue con el diagrama normativo Q'(F')-ANOR en el que se usa la relación anortita-ortosa como factor discriminante. En este trabajo se presenta el diagrama químico SiO2 -100·CaO/(CaO+K2 O) que reproduce en gran parte la clasificación normativa citada pero de forma simplificada, utilizando solamente tres componentes químicos discriminantes (SiO2 , CaO y K2 O). La delimitación y nomenclatura de los campos se ha realizado de forma empírica tomando como ejemplo el diagrama normativo y la representación de análisis de rocas ígneas características. El límite de saturación en sílice aproximado se ha dibujado como una recta que une las composiciones feldespáticas, comprendidas entre la ortosa y la anortitaMagmas can form plutonic or volcanic rocks of the same chemical composition. The modal composition of the plutonic rocks can be quantified but in the case of volcanic rocks this is not always possible, because of its aphanitic texture and presence of glass. These characteristics prevent a mineralogical classification in equivalent diagrams for both types of rocks. To resolve this problem, the IUGS recommends the use of chemical TAS diagram in cases where obtaining the modal composition is not possible, in an attempt to adjust its nomenclature to that represented in the QAPF modal diagram. A best approximation is obtained with the normative diagram Q'(F')-ANOR in which the anorthite and the orthoclase are used as a discriminating factor. In this work, the chemical SiO2 -100·CaO/(CaO+K2 O) diagram is presented, which largely reproduces the aforementioned normative classification but in a simplified form since it uses only three discriminating chemical components (SiO2 , CaO and K2 O). The delimitation and nomenclature of the fields has been undertaken empirically using as an example the normative diagram and plotting the analyses of typical igneous rocks. The approximate limit of silica saturation has been drawn as a straight line joining the feldspathic compositions, between orthoclase and anorthit

Comparative study of the classification of plutonic and volcanic rocks using the normative Q' (F')-ANOR and chemical SiO2-100·CaO/(CaO+K2O) diagrams

To obtain a classification of igneous rocks, compatible with the QAPF classification, in the absence of modal analyses, a chemical diagram using the same discriminating elements as the Q'(F')-ANOR normative diagram has been proposed. These elements, Si, Ca and K, are essential constituents of quartz, feldspars and feldspathoids. The different proportions between these minerals are the basis of the QAPF modal classification but also those of the normative classification Q'(F')-ANOR. The chemical diagram SiO2100·CaO/(CaO+K2O) uses these same elements but with the important difference that they are treated as independent variables. This characteristic allows igneous rocks to be classified with a nomenclature equivalent to that obtained by modal analyses, using only Si, Ca and K analytical data. The plotting of a set of representative plutonic and volcanic rocks reveals a remarkable concordance between both diagrams. However, some discrepancies and overlaps occur in the subsaturated fields due to the inability of the method to determine whether the lower silica content is due to the presence of olivine or feldspathoids. The samples selected belong to igneous series from diverse geotectonic areas , thus helping to evaluate the results in a global context

A chemical approximation to the modal QAPF and normative Q' (F')-ANOR classification of the igneous rocks based on their SiO2-CaO-K2O content

Magmas can form plutonic or volcanic rocks of the same chemical composition. The modal composition of the plutonic rocks can be quantified but in the case of volcanic rocks this is not always possible, because of its aphanitic texture and presence of glass. These characteristics prevent a mineralogical classification in equivalent diagrams for both types of rocks. To resolve this problem, the IUGS recommends the use of chemical TAS diagram in cases where obtaining the modal composition is not possible, in an attempt to adjust its nomenclature to that represented in the QAPF modal diagram. A best approximation is obtained with the normative diagram Q'(F')-ANOR in which the anorthite and the orthoclase are used as a discriminating factor. In this work, the chemical SiO2-100·CaO/(CaO+K2O) diagram is presented, which largely reproduces the aforementioned normative classification but in a simplified form since it uses only three discriminating chemical components (SiO2, CaO and K2O). The delimitation and nomenclature of the fields has been undertaken empirically using as an example the normative diagram and plotting the analyses of typical igneous rocks. The approximate limit of silica saturation has been drawn as a straight line joining the feldspathic compositions, between orthoclase and anorthit

Procesos de mezcla incompleta entre un magma granodiorítico y una intrusión diorítica parcialmente consolidada en Llafranc (Cordillera Litoral Catalana, NE de la Península Ibérica)

La presencia de rocas intrusivas heterogéneas originadas por mezcla de magmas es frecuente en distintos ámbitos geológicos. En este trabajo se estudian los posibles procesos que han dado lugar a la formación de las cuarzodioritas hercinianas de Llafranc. La morfología de los contactos entre las zonas granodioríticas y cuarzodioríticas y la distribución de los fenocristales sugieren que se produjo una inyección de magma granodiorítico, en una intrusión cuarzodiorítica parcialmente consolidada pero aún con fluidez suficiente para mezclarse de forma limitada. La evolución conjunta de los dos magmas a temperaturas decrecientes genera una secuencia en la tipología de los contactos que empieza con contactos difusos curvilíneos, con marcado intercambio de fases minerales, y acaba con contactos netos, rectilíneos sin intercambio cristalino apreciabl

Die COVID-19-Pandemie: Die Rolle von Demografie und Demograf*innen

Die COVID-19-Todesfälle sind nur die Spitze eines Eisbergs. Staatliche Maßnahmen zur Unterstützung von Familien könnten die Auswirkungen der Pandemie auf andere demografische Ereignisse, wie zum Beispiel die Fertilität, abmildern. - Bei der Bekämpfung von COVID-19 sollten politische Entscheidungsträger*innen berücksichtigen, inwiefern die Altersstruktur und Formen des Zusammenlebens die Infektionsund Todeszahlen beeinflussen können. - Auf nationaler Ebene müssen die statistischen Ämter ihre Datenerfassungssysteme verbessern, sodass auf Registerdaten besser und schneller zugegriffen werden kann. - Das Ausmaß der Übersterblichkeit variiert stark zwischen europäischen Ländern, und auch innerhalb eines Landes gibt es deutliche Unterschiede. Die genauen Gründe für den Erfolg oder Misserfolg einer Region stehen noch nicht fest, sodass in diesem Bereich mehr Forschung notwendig ist

Strain-monitoring of a concrete tunnel lining with distributed optical fiber sensors

Despite their advantageous performance and reliability, distributed optical fiber sensors (DOFS) still constitute a recent technology and their reliability and accuracy when applied to real world structures is still under probation since there is still room for improvement and for widening their applicability. In general, standardized guidelines need to be developed to ensure success in every DOFSs deployment regarding fiber bonding to the structure, temperature affections on readings, postprocessing of reading anomalies, among other factors. However, real applications, as in the one presented in this paper, show that DOFS are anticipated to have a very important role in Structural Health Management of tunnels in the near future if correctly understood and developed. This paper addresses the implementation of a Distributed Optical Fiber Sensor system (DOFS) to the existing TMB L-9 metro tunnel in Barcelona for Structural Health Monitoring (SHM) purposes as the former could potentially be affected by the construction of a nearby residential building. The results show a good performance of this novel technique in the monitoring of strain along the whole affected sections during the construction of a nearby building. In fact, the DOFS readings reproduce very accurately the tunnel deformation process. The tendencies observed by the sensors were forecasted by a simple theoretical model. The monitoring of the strain at many points in the critical section allowed to conclude that the nearby construction only slightly affected the lining stresses and that safety was guaranteed during the whole monitored period.The authors thank COTCA and TMB respectively for providing access to the necessary data regarding the case study and supporting this research. We would also like to thank Ph D student Mattia F. Bado who provided insight that greatly assisted this research during the data post-processing phase. The authors are indebted to the Spanish Ministry of Economy and Competitiveness for the funding provided through the research project BIA2017-86811-C2-1-R. All these projects are funded with FEDER funds. Authors are also indebted to the Secretaria d’ Universitats i Recerca de la Generalitat de Catalunya for the funding provided through Agaur (2017 SGR 1481).Postprint (author's final draft

The Environmental Impact of Major Sport Events (Giga, Mega and Major): A Systematic Review from 2000 to 2021

In the context of the Sustainable Development Goals interest and concerns about the environmental impact of major sporting events have become increasingly widespread, voiced not only by organizers, but also spectators and residents of affected areas, as well politicians and institutional representatives of the host territories. There are multiple studies of the economic, social, and legal impacts of major sport events. Although several studies have pointed to a range of environmental impacts, there is no clear consensus on the effects that a major event can have on the natural environment. Thus, the aim of this article is to carry out a systematic review of the state of the art. Following the steps proposed by the PRISMA protocol, a selection of scientific articles from between 2000 and 2021 was made. The overall analysis shows that the negatives outweigh the positives, as only 32.91% of the effects described in the articles are deemed to be positive, with 62.03% deemed to be negative, and finally, 5.06% found to be inconclusive. With varying degrees of success, organizers and promoters of major events are already attempting measures to reduce negative impacts and enhance positive ones

The dioritic-gabbroic intrusive complex of Susqueda (Montseny–Guilleries massif, Catalonia): lithological units and petrographic features

The intrusive complex of Susqueda constitutes the biggest association of plutonic mafic rocks of the Catalonian Coastal Ranges. It is located in the contact between the large calc-alkaline granitoid intrusions and the Paleozoic country rocks affected by Hercynian regional metamorphism. Intrusive relationships denote contemporaneity of basic magmas and, at least, an acid magma intrusion. A significant part of the outcrop consists of a heterogeneous mixing zone between the two magmas (mingling). The intrusion is made up of two oval-shaped outcrops about 3 km long, elongated in the N–S direction and separated by a NW–SE fault. In these units, the compositions of the plutonic rocks range from quartz diorites and tonalites (in the mixing zones) up to olivine hornblendites. Even though its distribution is quite heterogeneous, a preliminary cartography was made including the different petrographic types in three main groups: 1) hornblende gabbros and olivine hornblendites; 2) biotite-hornblende diorites; and 3) heterogeneous mixing zone between hornblende-biotite quartz diorite, granodiorite, and tonalite. The predominant mineral composition consists of plagioclase and amphibole, typical of dioritic rocks. Nevertheless, in a great part of the outcrop the plagioclase widely exceeds the 50% in An, typical of gabbroic rocksEl complejo intrusivo de Susqueda constituye la mayor asociación plutónica de rocas máficas del batolito de las Cordilleras Costeras Catalanas. Se halla situado en el contacto entre grandes intrusiones de granitoides calcoalcalinos y rocas encajantes paleozoicas afectadas por el metamorfismo regional herciniano. Las relaciones intrusivas indican una clara contemporaneidad entre los magmas básicos y, al menos, una intrusión ácida. Una parte significativa del afloramiento consiste en una zona de mezcla heterogénea entre los dos magmas (mingling). La intrusión está formada por dos afloramientos ovalados de unos 3 km de longitud, alargados en dirección N–S y separados por una falla NW–SE. En su interior se distinguen diversos tipos de rocas plutónicas con composiciones que varían desde cuarzodioritas y tonalitas (en las zonas de mezcla) hasta hornblenditas olivínicas. Aunque su distribución es bastante heterogénea se ha realizado una cartografía preliminar, incluyendo los distintos tipos petrográficos en tres grupos principales: 1) gabros hornbléndicos y hornblenditas olivínicas, 2) dioritas hornbléndico-biotíticas y 3) mezcla heterogénea entre cuarzodioritas biotítico-hornbléndicas, granodioritas y tonalitas. La mineralogía dominante consiste en plagioclasa y anfíbol que es típica de rocas dioríticas. No obstante, en gran parte del afloramiento la plagioclasa supera ampliamente el 50% de An, propia de rocas gabroica