Geochemical variation among small eruptive centers in the central SVZ of the Andes: An evaluation of subduction, mantle and crustal influences

Subduction zone magmatism is an important and extensively studied topic in igneous geochemistry. Recent studies focus on from where arc magmas are generated, how subduction components (fluids or melts) are fluxed into the source of the magmas, and whether or how the subduction components affect partial melting processes beneath volcanic arcs at convergent boundaries. ^ At 39.5°S in the Central Southern Volcanic Zone of the Andes, Volcano Villarrica is surrounded by a suite of Small Eruptive Centers (SEC). The SECs are located mostly to the east and northeast of the stratovolcano and aligned along the Liquine-Ofqui Fault Zone, the major fracture system in this area. Former studies observed the geochemical patterns of the SECs differ distinctively from those of V. Villarrica and suggested there may be a relationship between the compositions of the volcanic units and their edifice sizes. This work is a comprehensive geochemical study on the SECs near V. Villarrica, using a variety of geochemical tracers and tools including major, trace and REE elements, Li-Be-B elements, Sr-Nd-Pb isotopes and short-lived isotopes such as U-series and 10Be. In this work, systematic differences between the elemental and isotopic compositions of the SECs and those of V. Villarrica are revealed and more importantly, modeled in terms of magmatic processes occurring at continental arc margins. Detailed modeling calculations in this work reconstruct chemical compositions of the primary magmas, source compositions, compositions and percentages of different subduction endmembers mixed into the source, degrees of partial melting and different time scales of the SECs and V. Villarrica, respectively. Geochemical characteristics and possible origins of the two special SECs—andesitic Llizan, with crustal signatures, and Rucapillan, to the northwest toward the trench, are also discussed in this work. ^

Development of a medium-capacity guideway transit planning guide

Rapid population increase and booming economic growth have caused a significant escalation in car ownership in many cities, leading to additional or, multiple traffic problems on congested roadways. The increase of automobiles is generating a significant amount of congestion and pollution in many cities. It has become necessary to find a solution to the ever worsening traffic problems in our cities. Building more roadways is nearly impossible due to the limitations of right-of-way in cities. Studies have shown that guideway transit could provide effective transportation and could stimulate land development. The Medium-Capacity Guideway Transit (MCGT) is one of the alternatives to solve this problem. The objective of this research was to better understand the characteristics of MCGT systems, to investigate the existing MCGT systems around the world and determine the main factors behind the planning of successful systems, and to develop a MCGT planning guide. The factors utilized in this study were determined and were analyzed using Excel. A MCGT Planning Guide was developed using Microsoft Visual Basic. ^ A MCGT was defined as a transit system whose capacity can carry up to 20,000 passengers per hour per direction (pphpd). The results shown that Light Rail Transit (LRT) is favored when peak hour demand is less than 13,000 pphpd. Automated People Mover (APM) is favored when the peak hour demand is more than 18,000 pphpd. APM systems could save up to three times the waiting time cost compared to that of the LRT. If comfort and convenience are important, then using an APM does make sense. However, if cost is the critical factor, then LRT will make more sense because it is reasonable service at a reasonable price. If travel time and safety (accident/crush) costs were included in calculating life-cycle “total” costs, the capital cost advantage of LRT disappeared and APM could become very competitive. The results also included a range of cost-performance criteria for MCGT systems that help planners, engineers, and decision-makers to select the most feasible system for their respective areas. ^

Isotopic studies of the Guerrero composite terrane, west-central Mexico: Implications for provenance of crustal rocks and genesis of ore metals

A variety of world-class mineral deposits occur in Mesozoic and Tertiary rocks of the Guerrero terrane. New Pb isotope analyses of various crustal units and ores from distinct subterranes of the Guerrero terrane are presented to trace metal sources in these deposits and infer source reservoirs. New Sr and Nd isotope results are provided to gain insight into the provenance of the crustal rocks from the Guerrero terrane. Triassic schist samples from the Arteaga Complex and Triassic-Jurassic phyllite and slate samples from the Tejupilco metamorphic suite contain radiogenic Pb (206Pb/204Pb = 18.701–19.256) relative to bulk earth models. Cretaceous sedimentary rocks of the Zihuatanejo Sequence are more radiogenic (206Pb/204Pb = 18.763–19.437) than samples from the Huetamo Sequence (206Pb/204Pb = 18.630–18.998). Tertiary intrusive rocks from La Verde, Inguaran, La Esmeralda, and El Malacate plot to the right of the average Pb crust evolution curve of Stacey and Kramers (206Pb/204Pb = 18.705–19.033). Ores from the La Verde and La Esmeralda porphyry copper deposits yield isotopic ratios (206Pb/204Pb = 18.678–18.723) that are generally less radiogenic than the host igneous rocks, but plot within the field defined by the sedimentary rocks from the Huetamo Sequence. Tertiary intrusive rocks from the Zimapan and La Negra districts in the Sierra Madre terrane plot above and to the right of the Stacey-Kramers reference line (206Pb/204Pb = 18.804–18.972). Lead isotope ratios of ore minerals from the Zimapan and La Negra skarn mines ( 206Pb/204Pb = 18.775–18.975) resemble those of the associated igneous rocks, implying a magmatic Pb input in the skarn deposits. New Sr and Nd isotope data on metamorphic rocks (87Sr/ 86Sr = 0.707757–0.726494 and 143Nd/144 Nd = 0.512109–0.512653) suggest that the basement of the Guerrero terrane originated from sources that had been derived from an old cratonic area. The narrow ranges and generally low 87Sr/86Sr ratios (0.704860–0.705755) and 143Nd/144Nd values (0.512765–0.512772) above that of bulk earth for igneous rocks from Inguaran, El Malacate, and La Esmeralda suggest a relatively low degree of crustal contamination. However, the isotopic values for the La Verde site (87Sr/86Sr = 0.708784 and 143Nd/144Nd = 0.512640) may indicate the involvement of a more evolved crustal component.

Character education in a Muslim school: A case study of a comprehensive Muslim school's curricula

Deteriorating social behavior, negative media influence and violence among adolescents have given cause to pause and assess character development for the youth of this country. The purpose of this case study was to examine how a Muslim school’s curricula implemented character education. This study used a qualitative single-case methodology to examine character education as it was experienced by the participants in a private Muslim school. Data were collected from participant interviews, document analysis, and observations of classrooms, daily activities and special events. Data were analyzed to determine how character education was defined by the school, the method of delivery for the character education initiatives and the implementation of character education in this Muslim school. Analysis was based on Character Education Partnership’s (CEP) Eleven Principles of Effective Character Education (2007). The results of the study revealed: (a) participants defined character education using varied traits, processes, and expected behaviors. (b) The school delivers its character education curriculum primarily through the Islamic studies division; an add-on delivery method. Still, there was evidence of partial integration of character education in the core courses and (c) based on CEP’s Eleven Principles four were present and five were partially present in the school’s character education initiatives. Findings also revealed that the school’s emphasis on values, morality and spirituality was instrumental in their teaching character. Findings suggest that if participants in the school community work together they might formulate a definition of character education based on common process and expected behavior and create a collaborative working relationship to implement a character education program. Finally, addressing the absent and partially absent elements of the eleven principles could enhance the school’s character education initiatives. The study provides a process by which religious schools could examine their character education programs. The criteria used to measure the use of character education elements are transferable to other settings; however, this method of study does not allow generalization of findings.