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Fault activation/reactivation timing determination using Illite-Age Analysis(IAA)

Fault activation event can be determined by plotting the results of the optimized illite-polytype quantification and the K-Ar age-dating results of clay fractions separated from the fault clays.


Photograph of Chugaryeong fault, showing fault damage zones consisting of cataclasites and fault clays (a), and an enlarged photograph showing the outcrop scale subsidiary faults (b).


Illite–polytype quantification for each size fraction of the fault clay using the full–pattern–fitting method, and the illite age analysis (IAA) plot of the relative proportions of 2M1 illite against the function exp(λt) –1. Illite ages can be determined at the intercepts of 0% and 100% 2M1 illites by extrapolating the regression line.


Examples of IAA plots for all size fractions of all the fault clay samples from Chugaryeong fault, indicating that 4 times fault activation events occurred during the Late Cretaceous to Paleogene period.

Moving sense analysis of active fault plane using shape preferred orientation(SPO) of 3D micro-CT image

Development and application of Shape Preferred Orientation (SPO) analysis using synchrotron 3D micro-CT imaging, and image filtering process using Amira software, and 3D geometric information acquisition by Matlab calculation.


Examples of 3D micro-CT image after image filtering process using Amira, and equal-angle stereo-net plots of Matlab calculation results

Microtexture characterization of rocks and minerals to reveal the precipitation, alteration, mineral-fluid interaction,internal textures of minerals,

Polished thin sections of samples are prepared for the microtextural description and the chemical characteristics of minerals using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).


Examples of BSE images from the fault clay samples (a-d). EDS results of both illites were plotted on the M+–4Si–R2+diagram(Meunier and Velde, 1989)(e).


SEM-BSE and EPMA-COMPO images of drilling cores from Pohang basin. Chl: chlorite; Ill: illite; Kln: kaolinite; Cc: calcite; Py: pyrite; Dsl: dissolution; Si: silica polymorph.

Magma and magmatic-hydrothermal fluid evolution related to tectonics based on trace/REEs mineral chemistry

Microprobe quantification and elemental mapping of major/trace elements and REEs using EPMA and LA-ICP-MS for some compositional zoning minerals provide the critical information for the magmatic-hydrothermal fluid evolution history.


Examples of REE patterns of garnets from the Sangdong and Weondong deposits.


Qualitative LA-ICP-MS mapping images of Sangdong garnet.

Crystal structure characterization using molecular orbital simulation (MOS)

Integrated approaches using both mineralogical/geochemical analysis and molecular orbital simulation for some zoning minerals and silicate clays provide the crucial information for interpreting some crystal structures, which cannot be solved experimentally.


The refined octahedron units of Fe sites and Cl position in the newly proposed Ge-akaganéite after the rietveld refinement (a), the optimized crystal structure of the newly proposed Ge-akaganéite model after DFT calculation (b), and the optimized hydrogen bonds structure around of the newly proposed Ge-tetrahedra in tunnel site of Ge-akaganéite model after DFT calculation (c).

Clay mineral applications, including antimicrobial-clay composites for medical target therapy

Development of clay composites induced by intercalation of antibiotics into smectite, a new drug delivery system for target therapy, can be applied to eradicate Helicobacter pylori.


Systematics of antibiotic-smectite intercalation as drug delivery system and target therapy to eradicate Helicobacter pylori.