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Mineralization, Magmatism and Tectonics along the Loei Fold Belt, Northeastern Thailand
Get PDF秋田大学博士（資源学）Permo-Triassic granitoids from various areas along the Loei Fold Belt, northeastern Thailand, were studied. The aim of this work is to document the petrochemical characteristics of granitoids in the Loei Fold Belt. The Loei Fold Belt is an 800 km long, north-south trending fold belt that hosts several epithermal Au-Ag and skarn Au-Cu-Fe deposits. The study areas are divided into five regions i.e., (1) Mung Loei, (2) Phu Thap Fah - Phu Thep, (3) Phetchabun, (4) Nakon Sawan - Lobburi and (5) Rayong - Chantaburi region. The granitoids consist of monzogranite, granodiorite, monzodiorite, tonalite, quartz-syenite and quartz-rich granitoids. These granitoids are composed of quartz, plagioclase, K-feldspar at varying proportions with mafic minerals such as hornblende and biotite. Accessory minerals, such as titanite, zircon, magnetite, ilmenite, apatite, garnet, rutile, and allanite are also present. Magnetic susceptibilities of granitoids vary from 6.5×10-³ to 15.2×10-³ in SI unit in Muang Loei, from 0.1×10-³ to 29.4×10-³ in SI unit in Phu Thap Fah – Phu Thep, from 2.7×10-³ to 34.6×10-³ in SI unit in Petchabun, from 2.4×10-³ to 14.1×10-³ in SI unit in Nakon Sawan – Lobburi and 0.03×10-³ to 2.8× 10-³ in SI unit in Rayong – Chantaburi. Concentration of major elements suggests that these intermediate to felsic plutonic rocks have calc-alkaline affinities. Concentration of rare earth elements (REE) of the granitoids normalized to chondrite displays moderately elevated LREE and relatively flat HREE patterns, with distinct depletion of Eu. Rb vs. Y/Nb and Nb/Y tectonic discrimination diagrams illustrate that the granitoids from Muang Loei, Phu Thap Fah – Phu Thep, Phetchabun, Nakon Sawan – Lobburi and Rayong - Chantaburi formed in continental volcanic-arc setting. New age data from radiometric K-Ar dating on K-feldspar from granodiorite in Loei and Nakhon Sawan areas yielded 171±3 and 221±5 Ma, respectively. K-Ar dating on hornblende separated from diorite in Lobburi yielded 219±8 Ma. These age dating data suggest magmatism of Muang Loei occurred in the Middle Jurassic, and Nakon Sawan – Lobburi occurred in Late Triassic. Both Nb vs. Y and Rb vs. (Y + Nb) discrimination diagrams and age data indicate that Nakon Sawan – Lobburi granitoids intruded in Late Triassic at Nong Bua, Nakon Sawan province and Khao Wong Phra Jun, Lobburi province in volcanic arc setting. Muang Loei granitoids at the Loei province formed later in Middle Jurassic also in volcanic arc setting. Most of δ³⁴SCDT of pyrite separated from granitoids along Loei Fold Belt, range from -2.1 to +2.2‰. The negative δ³⁴SCDT values of ore minerals from skarn deposit suggest that the I-type magma has been influenced by light biogenic sulfur from local country rocks. The Au-Cu-Fe-Sb deposits correlates with the magnetite-series granitoids in Phetchabun, Nakon Sawan-Lobburi and Rayong - Chantaburi areas. Metallogeny of Au and Cu-Au skarn deposits, and epithermal Au deposit are related to adakitic rocks of magnetite-series granitoids from Phetchabun and Nakon-Sawan areas. All mineralization along the Loei Fold Belt are generated in the volcanic arc related to the subduction of Paleo-Tethys. T Al content of biotite of granitoids increase in the following order: granitoids associated with Fe and Au deposit < those with Cu deposit < barren granitioids. XMg of biotite in granitoids in Muang Loei, indicate the crystallization of biotite in magnetite-series granitoids under high oxygen fugacity condition. On the other hand, low XMg (<0.4) of biotite in magnetite-series granitoids in Phu Thap Fah – Phu Thep and Rayong – Chantaburi, indicate reduced environment, low oxygen fugacity, associated with Au skarn deposit (Phu Thap Fah) and Sb-Au deposit (Bo Thong), respectively. The magnetite-series granitoids at Phu Thap Fah having low magnetic susceptibilities and low XMg of biotite, were formed by reduction of initially oxidizing magnetite-series granitic magma by interaction with reducing sedimentary country rocks as suggested by negative δ³⁴SCDT values
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Retrospective earthquake spatial forecasting: magnetotelluric insights into fluid-driven intraplate seismicity in northern Thailand from 1994 to 2024
No full textAbstract This study investigates the role of crustal fluids in the seismogenesis of three significant intraplate earthquakes in northern Thailand: the 1994 Phan, 2014 Mae Lao, and the unexpected 2019 Wang Nuea events, which occurred after a decade of seismic quiescence. Utilizing 3D resistivity models derived from integrated 2015 and 2024 magnetotelluric (MT) surveys, we reveal complex, interconnected conductive systems beneath each seismically active region, indicative of fluid pathways extending from the lower to the near-surface crust. For the 2014 Mae Lao earthquake, a lower crustal fluid source ascends through a mid-crustal conductor with northward and southward extensions. A shared deep fluid source is implicated in the 1994 Phan earthquake; however, fluids follow a distinct southward migration pathway. The 2019 Wang Nuea earthquake also exhibits comparable lower and mid-crustal conductive structures and inferred fluid ascent, mirroring the Mae Lao system. Notably, a mid-crustal conductor was identified beneath the Wang Nuea region in our initial 2015 MT survey, but with the decades of seismic quiet, the link between this crustal fluid and the eventual earthquake was not anticipated, representing a missed opportunity for early spatial forecasting of the 2019 rupture. In all three events, the presence of fluids within the fault zones likely reduced their strength, leading to rupture when tectonic stress exceeded the critical threshold. The consistent presence of these conductive systems across these intraplate earthquakes suggests a unique characteristic of seismogenesis in northern Thailand, providing a valuable geophysical signature for future seismic hazard assessment and spatial forecasting. Graphical Abstrac
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