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. ^

A history of the presidency of National Taiwan University: The relationship between the university and an evolving democratic nation

Higher education always plays an important role in the development of a nation. Taiwan is no exception. Graduates of the National Taiwan University have occupied most of the important positions in this country and today many devote themselves to the development of Taiwan since the central government of the Republic of China (ROC) withdrew from Mainland China and re-located to Taiwan in the winter of 1949. The higher education system in Taiwan, including university and junior colleges, received special attention from the government except from 1945 to 1949 during the transitional period; the time of the early restoration year and the central government's retreating period from Mainland China.^ The five presidents of National Taiwan University who served from 1949 to 1993, Fu Szu-nien, Chien Seu-liang, Yen Chen-Hsing, Yu Chao-chung, and Sun Chen, are the subject of this research. All of the presidents were appointed by the government which established a direct connection between the government and the university leadership. The purpose of this study is to understand how each president balanced politically assigned roles and expectations with personal visionary academic responsiveness to the principles which define the university.^ Each president and his tenure were analyzed using historical research, a developed leadership model, an integration of role theory, Locke's leadership model, Wiles and Bondi curriculum leader tasks, and Burn's leadership style. Results of analyses of documents showed that all presidents of the National Taiwan University were highly respected due to their academic background, personal characteristics, and contribution to the university as a leader. Meanwhile, implementation and achievement of the presidents led to the conclusion that appointed university presidents had significant relationships with government policy. Their leadership style was affected strongly by their personal traits and knowledge and the social and political climate of the time. ^