scholarly journals Deposits, character and timing of recent eruptions and gravitational collapses in Tatun Volcanic Group, Northern Taiwan: Hazard-related issues

2010 ◽  
Vol 191 (3-4) ◽  
pp. 205-221 ◽  
Author(s):  
Alexander Belousov ◽  
Marina Belousova ◽  
Chang-Hwa Chen ◽  
Georg F. Zellmer
Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 395
Author(s):  
Liang-Chi Wang

Paleoecological data can be used to inform nature conservation practice. Dream Lake (DL) is the best-preserved peat bog in the Tatun Volcanic Group of northern Taiwan. We analyzed continuous pollen and charcoal data from a well-dated sediment core from DL to reconstruct the changes in climate, lacustrine condition, and floristic diversity during the last 4500 cal BP. An absence of volcanic ash from all sediments indicates weak volcanic activity. Significant changes in lithology and pollen composition show that DL changed from a deep lake to a shallow peat bog from 3000 cal BP onwards. The palynological diversity index was negatively correlated with fire frequency. A substantial decline in Isoetes (quillwort) spores suggests increased vulnerability during the peat bog period. Natural terrestrialization will lower the mean water depth of DL below the minimum required for Isoetes taiwanensis survival within 300 years. Our findings indicate that winter precipitation driven by intense East Asian winter monsoons is the critical force determining the long-term variation in floristic diversity and abundance of I. taiwanensis. This long-term ecological history of DL, derived using paleoecological techniques, will be used to inform conservation practice in the Tatun Volcanic Group.


1992 ◽  
Vol 149 (6) ◽  
pp. 889-906 ◽  
Author(s):  
M. G. PETTERSON ◽  
B. BEDDOE-STEPHENS ◽  
D. MILLWARD ◽  
E. W. JOHNSON

2021 ◽  
pp. 073563312199595
Author(s):  
Te-Lien Chou ◽  
Kai-Yu Tang ◽  
Chin-Chung Tsai

Programming learning has become an essential literacy for computer science (CS) and non-CS students in the digital age. Researchers have addressed that students’ conceptions of learning influence their approaches to learning, and thus impact their learning outcomes. Therefore, we aimed to uncover students’ conceptions of programming learning (CoPL) and approaches to programming learning (APL), and analyzed the differences between CS and non-CS students. Phenomenographic analysis was adopted to analyze 31 college students (20 CS-related, and 11 not) from northern Taiwan. Results revealed six categories of CoPL hierarchically: 1. memorizing concepts, logic, and syntax, 2. computing and practicing programming writing, 3. expressing programmers’ ideas and relieving pressure, 4. applying and understanding, 5. increasing one’s knowledge and improving one’s competence, and 6. seeing in a new way. Four categories of APL were also found, namely: 1. copying from the textbook, teachers, or others, 2. rote memory, 3. multiple exploration attempts, and 4. online or offline community interactions. Furthermore, we found that most CS students held higher level CoPL (e.g., seeing in a new way) than non-CS students. However, compared with non-CS students, CS students adopted more surface approaches to learning programming, such as copying and rote memory. Implications are discussed.


Author(s):  
Hsin-Fu Yeh ◽  
Hung-Hsiang Hsu

The Tatun Volcano Group (TVG) is located in northern Taiwan and consists of many springs and fumaroles. The Tayukeng (TYK) area is the most active fumarole site in the TVG. In this study, we analyzed the long-term geochemical variations of hydrothermal fluids and proposed a mechanism responsible for the variation in TYK. There are two different aquifers beneath the TYK area: a shallow SO42−-rich aquifer and a deeper aquifer rich in Cl−. TYK thermal water was mainly supplied by the shallow SO42−-rich aquifer; therefore, the thermal water showed high SO42− concentrations. After 2015, the inflow of deep thermal water increased, causing the Cl− concentrations of the TYK to increase. Notably, the inferred reservoir temperatures based on quartz geothermometry increased; however, the surface temperature of the spring decreased. We inferred that the enthalpy was lost during transportation to the surface. Therefore, the surface temperature of the spring does not increase with an increased inflow of deep hydrothermal fluid. The results can serve as a reference for understanding the complex evolution of the magma-hydrothermal system in the TVG.


2021 ◽  
Vol 176 (5) ◽  
Author(s):  
Sylvin S. T. Tedonkenfack ◽  
Jacek Puziewicz ◽  
Sonja Aulbach ◽  
Theodoros Ntaflos ◽  
Mary-Alix Kaczmarek ◽  
...  

AbstractThe origin and evolution of subcontinental lithospheric mantle (SCLM) are important issues of Earth’s chemical and physical evolution. Here, we report detailed textural and chemical analyses on a mantle xenolith suite from Befang (Oku Volcanic Group, Cameroon Volcanic Line), which represents a major tectono-magmatic structure of the African plate. The samples are sourced from spinel-facies mantle and are dominated by lherzolites. Their texture is cataclastic to porphyroclastic, and foliation defined by grain-size variation and alignment of spinel occurs in part of peridotites. Spinel is interstitial and has amoeboidal shape. Clinopyroxene REE patterns are similar to those of Depleted MORB Mantle (DMM) except LREEs, which vary from depleted to enriched. The A-type olivine fabric occurs in the subset of one harzburgite and 7 lherzolites studied by EBSD. Orthopyroxene shows deformation consistent with olivine. The fabric of LREE-enriched clinopyroxene is equivalent to those of orthopyroxene and olivine, whereas spinel and LREE-depleted clinopyroxene are oriented independently of host rock fabric. The textural, chemical and thermobarometric constraints indicate that the Befang mantle section was refertilised by MORB-like melt at pressures of 1.0–1.4 GPa and temperatures slightly above 1200–1275 °C. The olivine-orthopyroxene framework and LREE-enriched clinopyroxene preserve the protolith fabric. In contrast, the LREE-depleted clinopyroxene, showing discordant deformation relative to the olivine-orthopyroxene protolith framework, and amoeboidal spinel crystallized from the infiltrating melt. The major element and REEs composition of minerals forming the Befang peridotites indicate subsequent reequilibration at temperatures 930–1000 °C. This was followed by the formation of websterite veins in the lithospheric mantle, which can be linked to Cenozoic volcanism in the Cameroon Volcanic Line that also brought the xenoliths to the surface. This study therefore supports the origin of fertile SCLM via refertilization rather than by extraction of small melt fractions, and further emphasizes the involvement of depleted melts in this process.


2021 ◽  
pp. 106233
Author(s):  
Chih-Hsiang Yeh ◽  
Jia-Jyun Dong ◽  
Sara Khonevisan ◽  
C. Hsein Juang ◽  
Wen-Chao Huang ◽  
...  

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