The Relationship between the Mineral Characteristics and Spectral Induced Polarization for the Core Rock Samples from the Gagok Skarn Deposit

Abstract

In order to develop the evaluation techniques for the potential sulfide ore reserves, the relationships between the modal vol.%, grain sizes and textural characteristics of the constituent minerals (e.g., sulfides, oxides and skarn minerals) and the Spectral Induced Polarization (SIP) phase differences are examined for the nine rock cores collected from the Gagok Pb-Zn skarn deposit. The Gagok Pb-Zn skarn deposit occurs mainly along the intrusive contact between the Cretaceous granitic rocks and Cambrian Myobong slate and Pungchon limestone. The nine rock cores have been grouped into three showing distinctive SIP phase differences: the highest (Group I), intermediate (Group II) and lowest (Group III). In relation with the modal vol.% of minerals, Group I is characterized by higher pyrrhotite (25-38 vol.%) and amphibole (40-55 vol.%); Group II by intermediate pyrrhotite (7-13 vol.%) and higher garnet (44-68 vol.%); and lower pyrrhotite (1-7 vol.%) and higher pyroxene (24-66 vol.%) stand for Group III. Furthermore, the grains of all the major constituent minerals become smaller from Group I (<5 mm) through Group II (<2.5 mm) to Group III (<1.6 mm). In particular, the pyrrhotite contents and their grain sizes show logarithmic correlation with the SIP phase differences, Although we present here the results solely from nine samples, the systematic interrelations especially for pyrrhotite indicate the potential ability of SIP measurements as a new mineevaluation technique for the sulfide ore reservoir.

CALCITE-SATURATED FLUIDS TRAPPED IN FLUORITE FROM THE GAGOK Zn-Pb SKARN DEPOSIT, SOUTH KOREA

“…1c). However, the skarn is not welldeveloped near the contact between the porphyry and the sedimentary rocks (Yun & Einaudi 1982, Heo et al 2012). It appears that the dominant structural controls for the skarn formation were the presence of bedding plane-induced thrust faults and slate-limestone contacts along a north-northeast trend (Yun & Einaudi 1982, Heo et al 2012.…”

“…have examined the field relationships of the mineralization, mineralogical and geochemical characteristics, and genetic environments from this metallogenic belt (Kim et al 1981, Yun & Einaudi 1982, Koh et al 1992, Choi et al 2009, Heo et al 2012. However, there have been few reports on the fluids responsible for the skarnification process or ore precipitation.…”

“…The present work focuses principally on fluid inclusion aspects, including textural and compositional implications of fluid inclusions and fluid source, combined with petrological and geochemical data that build on previous works (Yun & Einaudi 1982, Heo et al 2012.…”

Physical Properties of Rocks at the Gagok Skarn Deposit

“…Photomicrographs of rock samples from the Gagok mine. amp = amphibole, mt = magnetite, pyrr = pyrrhotite, sch = scheelite(Heo et al, 2012).…”

“…스카른에 의하여 광화작용을 받은 암석은 일반적으로 Fig. 5 와 같이 자성이 강한 자류철석 및 자철석 등을 수반하는 것으 로 알려져 있고(Emerson, 1986;Heo et al, 2012), 반면 모암 인 석회암과 관입암은 주로 방해석, 석영 및 장석 등의 자성이 약한 광물들을 수반하고 있다. 이러한 이유로 스카른에 의해 광화작용을 받은 광석, 일부 스카른 및 슬레이트 시료는 대자 율이 주변모암 시료들과 현저한 차이를 보이는 것을 알 수 있다.…”