JpGU-AGU Joint Meeting 2017

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[JJ] Oral

B (Biogeosciences) » B-CG Complex & General

[B-CG10] [JJ] Interrelation between Life, Water, Mineral, and Atmosphere

Mon. May 22, 2017 1:45 PM - 3:15 PM 201B (International Conference Hall 2F)

convener:Kentaro Nakamura(Department of Systems Innovation, School of Engineering, University of Tokyo), Yohey Suzuki(Graduate School of Science, The University of Tokyo), Ken Takai(Extremobiosphere Research Center, Japan Agency for Marine-Earth Science & Technology), Yuichiro Ueno(Department of Earth and Planetary Sciences, Tokyo Institute of Technology), Chairperson:Kentaro Nakamura(Department of Systems Innovation, School of Engineering, University of Tokyo), Chairperson:Yuichiro Ueno(Department of Earth and Planetary Sciences, Tokyo Institute of Technology)

2:00 PM - 2:15 PM

[BCG10-02] Evaluation of heterogeneity of reaction-transport phenomenon in rock by sequential pore water extraction

*Tadashi Yokoyama1 (1.Graduate School of Integrated Arts and Sciences, Hiroshima University)

Keywords:pore water, dissolution, advection

Heterogeneity of dissolution/precipitation and solute transport in rock pores has been drawing attention in recent years. This phenomenon has been often studied using numerical calculation, but direct analysis of pore water is important to know what is actually occurring in pores. However, most previous studies have analysed the composition of bulk pore solution and it is difficult to discuss the detail of reactive-transport behaviour in pores using the bulk composition. In the present study, an experimental technique to sequentially extract pore water by applying various gas pressures to wet sample was used. With this technique, pore water can be extracted for each pore radius, which provides information on the heterogeneity of reaction and transport in pores. In the experiment, pure water was first passed through a sandstone core to induce dissolution in pores (flow-through reaction), then pore water was extracted for each pore size and solute concentrations were measured. The result of the experiment showed that the concentrations of Na, Ca, Mg, and Si increased with decreasing pore radius and that the concentration increases of Ca, Mg, and Na were greater than that of Si. Qualitatively, this result can be explained by a numerical model of the advection and dissolution in a single tube for different pore radii. However, the observed concentration increases were significantly greater than the model calculation, and it seems possible to evaluate the extent of the mixing of solutions in narrow pore and large pore by comparing the model calculation and experimental result.