The 4th LP-SAM* was held on August 1, 2018 (Wednesday). As stated below, three LP students presented results and progress reports of their researches in the field of mineral economics, volcanology, and economic geology, respectively:
Presenter 1: Juntao Wang (D1)
Sustainable use of resources is important taking into account the huge demand and high changing frequency of mobile phones in China. And a high collection rate may benefit the sustainable use of resources because of the following reuse and recycling of retired mobile phones rather than direct disposal. However, a high collection rate may differ from a high sustainable use of resources due to an inefficient reuse and recycling activity along with a shortened utilization time stimulated via various collection promotions. This study is aimed at improving the sustainable use of resource from customized collection behaviors under varying external circumstances. The whole supply chain of mobile phones is modeled through system dynamics for this specialized study. The technology on manufacturing and recycling and the resale quantity are designed as the two main external circumstance factors. The simulation result of the quantity of collected, resale and total required mobile phones in China is applied to estimate the corresponding resource efficiency of four different collection behaviors, which the resource efficiency defined in this study is used to rank the sustainable use degree of resources. The results confirm the difference between a high collection rate and a high sustainable use of resources and the collection behavior without differentiating the reusable and unreusable mobile phones is pointed out always outperform other collection behaviors regarding sustainable use of resources. This study also indicates the circumstance factors including the degree of technology on manufacturing and recycling, the resale quantity and the optimized supply chain can efficiently affect the sustainable use of resources. The result emphasizes the importance of these factors and indicates that these factors should be the premise considerations before launching a new collection promotion/behavior.
Presenter 2: James-Cesar Avisado Refran (D1)
The westerly subduction of the Pacific Plate along the eastern bounds of the Philippine archipelago induces the emergence of arc volcanoes along the eastern edge. On the other hand, the easterly subduction of South China Sea (SCS), Sulu Sea, and Celebes Sea, along trenches found west of the country (e.g. Manila Trench, Negros-Sulu Trench, and Cotabato Trench), produces a different chain of arc volcanoes in the west. Manguao Basalt is found on the western region of the archipelago, facing SCS. Geologically, the northern portion of the region is related to the extended continental region of mainland Eurasia prior to opening of SCS. The spreading of SCS allowed for the drift and transport of the Palawan microcontinent southwards until its eventual collision with the Philippine Mobile Belt. The presentation summarizes the observed lava flow features and character of the Manguao Basalt during the field work done last May 2018. The lava flow features included preserved lava fronts, lava lobes extending seaward, lava channels, tumuli cracks, and lava channels. Samples were acquired from onland and nearshore exposures of the lava field, chert mounds and a scoria cone. Initial macroscopic observations of samples show moderate to intense vesiculation with perceptible phenocrysts and xenoliths. Scorias from the cone are reddish from oxidation with lesser embedded phenocrysts. All samples will be prepared for petrographic and geochemical analyses.
Presenter 3: Adi Sulaksono (D1)
The enrichment of S2- is one of the factors that trigger porphyry copper mineralization. The studied drill cores intersect the potassic alteration zone of the Grasberg porphyry copper-gold deposit at ~1 km vertically, and unaltered intra-mineral monzodiorite at the deeper level. Magmatic oxybarometers for weakly altered and unaltered intra-mineral monzodiorite such as amphibole-titanite-magnetite-quartz assemblage, anhydrite, magnetite, and amphibole, consistently indicate an oxidized state of ore-forming magmas (≥ NNO+1.3). Initial hydrothermal events were extensive alteration and vein characterized by K-feldspar, biotite, magnetite, quartz, and anhydrite, which are followed by copper sulfide stages. The δ34S values of sulfide-sulfate mineral pairs formed during potassic episode indicate that the SO42-/H2S ratio was ~4 above 550ºC and ~1 below 550ºC. Occurrences of anhydrite in the early stages and higher SO42-/H2S ratio at temperatures >550ºC indicate a high activity of dissolved SO42- in the initial hydrothermal fluid exsolved from an oxidized magma. The fluid then likely to followed a rock buffer trajectory and became more reduced. Hydrothermal biotite after igneous amphibole and biotite that have chemical compositions more enriched in phlogopite component indicate that Fe2+ was liberated from igneous mafic minerals and oxidized to form magnetite, resulting in the H2S formation by the simplified reaction: 12FeO + SO42- + 2H+ → 4Fe3O4 + H2S.
*LP-SAM: Leading Program Student Activity Meeting
LP-SAM provides a platform for students of different research backgrounds and professors to interact. It is aimed at developing and sharpening students’ organization and communication skills in a global environment. At such meetings, students share the activities that they are/were engaged in during the course of the academic year. These activities include reports on research progress, field survey, conferences and field trips etc.
Assistant Professors Dr. Altansukh Batnasan and Dr. Kofi Adomako-Ansah manage the LP-SAM course.