| 講演要旨(和文) | | 斑岩銅鉱床や酸化鉄銅金鉱床などの非鉄金属鉱床探査では，賦存する黄鉄鉱や黄銅鉱などの硫化鉱物がIP効果を持つため，IP法電気探査が利用される．一方で探鉱において見いだされるIP異常の多くは経済的価値の低い黄鉄鉱の存在と関連付けられ，黄銅鉱など探鉱対象鉱物の直接的な指標とはなりえていない．鉱物を識別する方法の一つとして，多周波数で複素比抵抗を測定するSIP法の使用が考えられるが，黄銅鉱のみのSIP効果については分かっていない．本研究では黄銅鉱が持つSIP効果を明らかにするため，黄銅鉱粒子を含有させた人工試料の複素比抵抗を計測し，Cole-Coleモデルを用いて解析を行った．その結果，含有量の増加に伴う充電率の増加，粒径の変化による時定数の変化が確認された．また，黄銅鉱の周波数依存係数は黄鉄鉱とは異なることも確認された．このことは，SIP法電気探査で黄銅鉱を識別できる可能性を示唆する． |
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| | 講演要旨(英文) | | Induced polarization (IP) method is used in many cases of exploration for nonferrous metal deposits such as porphyry copper deposits and iron oxide copper gold deposits. This is because sulfide minerals such as pyrite and chalcopyrite have the IP effect. However, the target of exploration is a sulfide mineral containing valuable metals such as chalcopyrite, and pyrite is not generally targeted. One of the methods used to identify minerals is the spectral IP (SIP) method, which measures complex resistivity at many frequencies. Although the SIP effects on sulfide minerals or ores have been investigated, the SIP effect on chalcopyrite has not been thoroughly examined. To investigate the difference in the SIP effect between chalcopyrite and other minerals, we measured the complex resistivity of artificial samples that contained chalcopyrite particles. Then we tried to analyze the complex resistivity data using Cole-Cole model. The results show that the chargeability became larger as the content of particles is increased, and the time constant changes according the particle site. It was also confirmed that the frequency dependent coefficient of chalcopyrite differs from that of pyrite or magnetite. This indicates that the chalcopyrite and other minerals can be identified using SIP method. |
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