The 7th LP-SAM* was held on December 8th (Fri), 2017. The meeting was managed by Assistant Professor Batnasan Altansukh, which covered 3 topics including provenance of magma, volcanic (phreatic and phreatomagmatic) eruptions, and system dynamics for evaluation of resource efficiency presented by three LP students.
Presenter 1: Lloyd Heyson Singura (M2)
Currently, he is pursuing his master’s degree in petrology and volcanology and his research focuses on the study of the provenance of magma emitted in the 700 years ago eruption at Rabaul volcano that is an active volcano in Papua New Guinea. It is located in eastern part of New Britain Island about 700 km NE of Port Moresby in East New Britain Province and is well located in an active tectonic setting prone to active earthquakes and frequent eruptions. To understand the provenance of the magma formation, the fluctuation of the mineral chemistry and identify the stratigraphic platform of the 700 years old tephra sequence of Rabaul system, samples were collected from within the Rabaul to distal tephra dispersal (the neighboring New Ireland) as results from two field works to the volcano. Among them eleven samples of variable eruption age collected are currently subjected to chemical, mineralogical and petrographical analysis by ICP-MS, XRD, XRF, crystallography and microscope. Petrographical analysis under microscope for a proximal site (labelled JWM) samples showed a dominance of subhedral-to-anhedral clinopyroxene, minor orthopyroxene, olivine and plagioclase. The occurrence of interstitial glass and opaque minerals are prevalent in most of the tephra grains. It was indicated that the JWM outcrop was a 700 year old unique tephra deposit. It accumulated 8 defined tephra layers having alternating scoria lapilli and ash + pumice fall. Apart from the JWM tephra, the recent 2014 Tavurvur scoria bombs also contain about the same mineral assemblage but had mostly cumulus texture of larger anheral-to-subhedral clinopyroxene and orthopyroxene, minor olivine and tabular interstitial plagioclase and volcanic glass. The distal samples in west coast New Ireland were also bearing subhedral to anhedral clinopyroxene and minor brown glass and plagioclase with magnetite rich opaques. More geochemical analysis (XRF, EPMA and more SEM) are needed to compile his master degree thesis.
Presenter 2: Takumi Imura (D1)
His research on subvolcanic hydrothermal systems such as phreatic and phreatomagmatic eruptions is aimed to study the pre-eruptive interaction between magma and the subvolcanic hydrothermal fluid. To better understand the systems, petrographical and mineralogical characteristics of ash particles in hydro-eruption products from multiple active volcanoes, namely Tokachidake in central Hokkaido and Ontake volcano in central Honshu in Japan were studied using microscopes, XRD, SEM-EDS, and FE-SEM-EDS.
The 4.7-ka Ground Crater pyroclastic flow deposit, the 3.3-ka Ground Crater pyroclastic flow deposits, and the 1926AD lahar deposits on and around the source of the Tokachidake volcano were examined in his previous study. It was found that most ash grains in the 4.7-ka and 1926AD products belong to either of silica and alunite types alteration. Whereas the 3.3-ka products are rich in kaolin-type ash that exhibits a stratigraphic variation in the proportion of unaltered ash. All alterations observed in the ash samples imply that acidic hydrothermal fluids in a short-lived subvolcanic hydrothermal system passed through the rocks/minerals.
His current studies have revealed woodhouseite (phosphate-sulfate) as aluminum-phosphate-sulfate (APS) minerals in Ontake volcano. Woodhouseite is mainly occurred in the acidic-altered ash grains associated with intensely-acidic alteration area. The ash grains are classified into two types based on their petrological and mineralogical occurrence: Alunite-hosted type APS and Vein-type APS. The APS minerals coexist with silica minerals - pyrophyllite or silica minerals - kaolin minerals. The results suggest that the subvolcanic hydrothermal system beneath Ontake proceeded rock alteration process corresponding to a porphyry system.
He will investigate further the properties of hydrothermal alterations such as temperature and environmental conditions of the multiple volcanoes, and an evolutional image of the subvolcanic hydrothermal systems based on the mineralogical and petrographical characteristics and the tendency of hydro-eruption mechanism in each volcano.
Presenter 3: Juntao Wang (M2)
Due to the limited resources on the earth, improvement of the resource efficiency to identify increasing consumptions is very important. Hence, the main objectives of his research are (a) to evaluate the resource efficiency of mobile phone reuse chain, (b) to improve the performance by perfecting the reuse chain. The mobile phone reuse chain starts from the collection to the sales of the second-hand mobile phones. A mobile phone reuse chain model is firstly established through the system dynamics based on the concept of a general supply chain model that consists of four parts, including demand forecasting, stock adjustment, collection scheduling and demand fulfillment. The model was simulated using Vensim for three years of simulation period and the quantity of the collected products, reused products as well as the WEEE are gained as the results.
Based on the simulation results, the behavior of the reuse chain is firstly studied and the characteristics of the lag, amplification and oscillation have been pointed out by comparing with a static analysis. The simulation results influenced by the market types defined to capture the demand trend of second hand products forward the comprehensive regulation. Meanwhile, the resource efficiency is calculated according the equation defined in this study and the result is verified. The resource efficiency study emphasizes the uncertainty of the mobile phone reuse chain’s resource efficiency and points out that the collection quantity itself cannot well reflect the extent of resource efficiency once the mobile phone reuse is well applied. It is also indicated that the proper end-of-life treatment of the disposal WEEE along with the reuse chain applied, the additional promoted demand of the new products by the aggressive collection will induce less influence on resource efficiency. A new comprehensive policy and the coordination of the different policies need to be further improved to promote the resource efficiency.
*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.