A couple of Au-Ag-bearing epithermal quartz veins of Cretaceous(87.9Ma) in age are developed in the Cretaceous(112Ma) granodiorite batholith which was emplaced in Mesozoic Baegyari sedimentary formation. Au minerals consist mostly of electrum with a 54.2-61.9 wt% Au and are closely associated with sulfide minerals including pyrite, chalcopyrite, pyrrhotite, galena and sphalerite. Homogenization temperatures of fluid inclusions in quartz, fluorite and calcite are $196-368^{\circ}C$ (avg. $240^{\circ}C$), $74-176^{\circ}C$ (avg. $115^{\circ}C$) and $75-200^{\circ}C$ (avg. $119^{\circ}C$) respectively. Sulfur isotopic compositions( +5- +8‰) of ore sulfides indicate a deep-seated sulfur origin. Oxygen isotope compositions of different stages of quartz vary from +5.6 to +9.3‰ and calculated ${\delta}^{18}O$ values of ore fluid at $250^{\circ}C$ range from -3.2 to +0.4‰, reflecting an isotopically evolved ore fluid mixed with a $^{18}O$ depleted meteoric water under the variable mixing ratios between hydrothermal and meteoric waters. Isotopic data of calcite minerals support the above conclusions.

Pyrophyllite, kaolinite, and alunite deposits distributing in Southwestern parts of Cheonnam are classified into three types of minerals assemblages by the results of X-ray diffraction analysis etc. The first mineral assemblages contains pyrophyllite, kaolinite, dickite, quartz, diaspore and/or corundum, the second one contains alunite inseads of corundum, and the third one contains alunite without pyrophyllite and diaspore. It is can be considered that the depoSits which consist mainly of pyrophyllite are formed higher temperature than the other deposits. Judging form the chemical analyses the chemical compositions of hydrothermal solutions acting to the deposits seem to be relatively simple. But the hydrothermal solutions which generated Dogcheon, Jugjcon, Ogmaesan, and Seongsan mine contain rather somewhat higher $K_2O$. The values of the Trace Elements and REE analysis of the host rocks of deposits suggest that the host rocks are these deposits are the last products of magmatic differentiation.

Gold-silver deposits of Deogheun and Beopjeon mines are composed of veins emplaced in Jurassic granite batholith. Based on ore structure and ore mineralogy, four distinct stages of mineral deposition are recognized in these ore deposits. Gold and silver minerals in Deogheun and Beopjeon-A ore deposits are precipitated in stage III and stage II, respectively. Mineral constituents of ores from these deposits are pyrite, sphalerite, arsenopyrite, pyrrhotite, chalcopyrite, galena, tetrahedrite, electrum, quartz and rhodochrosite. Cubanite, argentite and pyrargyrite occur only in Deogheun ore deposits. Ag content of electrum range from 42 to 66 atomic % in both ore deposits. Filling temperature of fluid inclusion from both ore deposits are as follows; stage I, $211-289^{\circ}$ ; stage II, $205-290^{\circ}$ ; stage III, $190-260^{\circ}$ ; stage IV, $136-222^{\circ}$ in Deogheun ore deposits. In Beopjeon-A ore deposits, stage I, $255-305^{\circ}$ ; stage II, $135-222^{\circ}$ ; stage III, $148-256^{\circ}$ ; stage IV, $103-134^{\circ}$. Salinities of fluid inclusions range from 1.6-8.5 wt. % equivalent NaCl in both ore deposits. Sulfur fugacities through stage II and III in Deogheun ore deposits inferred from data of mineral assemblage and fluid inclusion range from $10^{-11.0}-10^{-16.1}$1bars. Fluid pressure estimated from fluid inclusions which reveal boiling evidence range from 30-190 bars during mineralization in Deogheun ore deposits.

This study has been carried out on the Pegmatites, Naedeogri Granites, Nonggeori Granites and Metasedimentary rocks in the middle area of Taebaeksan region to investigate the geochemical properties and possibility of productivity. Pegmatites are characterized by metamorphosed anatectic pegmatite and differentiated magmatic pegmatite, and are mixed type of rare-element pegmatite and mica-bearing pegmatite by the classification of Ginsburg(1979). The petrological type of the igneous rocks is thought to be calcalkali, subalkaline and peralumious. According to chemical variations against D. I., differentiation trends from Naedeogri and Nonggeori Granites through non-mineralized pegmatites to mineralized pegmatites are supposed. From the relationship between oxided and $SiO_2$, pegmatites and Nonggeori Granite have shown similar tendencies and bulk composition of pegmatites and similar to metasedimentary rocks near the intrusives. By judging the correlations of trace elements, it is elucidated that pegmatites adjacent to Naedeogri and Nonggeori Granites have been originated in magma differentiation from these granites and the others have been differentiated by remelting or partial melting from metasedimentary rocks. $Sp_5$, $Sp_8$, and $Sp_9$ pegmatites are considered as productive rocks, and $Sp_4$, $Sp_6$, $Sp_7$, $Sp_{10}$, $Sp_{11}$, and $Sp_{12}$ pegmatites and granites are supposed to have a weak productivity, in terms of element ratios related with Sn mineralizations. Tourmalines in productive pegmatites are formed under the circumstance of Li-poor granitoids and associated with pegmatites, and the others are seemed to be originated in metapelites and metapsammites which are not coexisting with an Al-saturating phase. Three types of chemical zoning are noticed in tourmalines: (1) apparently homogeneous compositional patterns, (2) a continuous core-to-rim zoning and, (3) a discontinuous core-to-rim zoning. From results of EPMA of tourmalines, Al, Mg and Ca increase closer to rim, while Fe decreases.

Magnetic anisotropy of a total of 213 independently oriented Tertiary rock samples from Pohang-Ulsan area has been studied. The sampled strata comprise basalts, tuffs and black shale, and range in age from Eocene to Miocene. The previous palaeomagnetic studies indicate that their magnetic carrier minerals are titanomagnetites. Among 23 sampled sites, 11 sites were found to preserve magnetic load foliation parallel to the bedding plane caused by the Iithostatic load of the overlying strata. Other 4 sites showed magnetic lineation indicating the flow direction of lava and tuffs. The remaining 8 sites revealed the magnetic tectonic foliation nearly vertical to the bedding plane. This magnetic foliation is interpreted to be generated by tectonic compression which acted nearly horizontally during the solidification stage of the strata. The compression directions deduced from the tectonic foliation of the 8 sites can be grouped into internally very consistent two group: a N-S trending one and the other WNW-ESE trending one. It is interpreted that the former N-S compression was associated with the N-S spreading of the East Sea(Sea of Japan) and the dextral strike-slip movement of the Yangsan-Ulsan fault system. The latter WNW-ESE compression is interpreted to represent the folding and reverse faulting activity in the Korean and Tsushima straits during middle/late Miocene times.

Controlled source audio-frequency magnetotelluric (CSAMT) has the great advantage of efficient mapping resistivity distribution and relatively deep depth of investigation. Moreover, CSAMT may be regarded more attractive than audio-frequency magnetotelluric in the sense of the strong and controllable signal. However, it has the problem such as undershoot and/or near-field effect that is hard to be interpreted if the interpretation method of MT is directly applied. The problem arises from the existance of controlled source which makes CSAMT attractive. So the characteristics of CSAMT response should be thoroughly understood prior to interpretation stage. In this study, numerical modeling program for horizontally layered earth was developped for the interpretation of CSAMT field data. CSAMT field survey was run as a follow-up to resistivity dipole-dipole study over the same survey line at Bongmyung coal mine. The survey used a grounded dipole source 2 Km in length and located 7.5Km south in this study. A good agreement between field CSAMT data and calculated data was demonstrated even in geologically complex earth situations.

Palemagnetic study on the Deadong Super Group in the Mungyong area has been carried out to obtain the direction of NRM and virtual geomagnetic pole(VGP), and to investigate geomagnetic stratigraphy and geotectonic evolution. Twenty eight core specimens from five sites in Dangog and Bongmyongsan Formations yield magnetically stable results by thermal demagnetization test. Mean declination and inclination of Dangog and Bongmyongsan formations are $52.4^{\circ}E$ and $-57.3^{\circ}$, respectively, which indicate reversal polarity. VGP is located at $1.2^{\circ}N$ in latitude and $269.4^{\circ}E$ in longitude, which is quite different from those of other contemporary formations in China. This suggests that the study area has suffered from differnt tectonic movement caused by Daebo Orogeny occurred in the Korean Peninsula during post-Daedong and pre-Kyongsang Systems. As compared VGP of Daedong Super Group in the Mungyong area with wordwide Mesozoic paleomagnetic polarity stratigraphy, it is correlated with the reverse Epoch in the Graham normal interval. This suggests that the time of formations of Dangog and Bongmyongsan is in the age of 190-195 my.

Foliated granites between Damyang and Jinan are subdivided into Daegang foliated granite, Foliated hornblende biotite granodiorite, Sunchang foliated granodiorite, Foliated two mica granite and Samori foliated granite by mineral and texture. From EPMA data of the foliated granites following results are achieved. Composition of plagioclase are correspond to andesine, oligoclase and albite in Foliated hornblende biotite granodiorite, Sunchang foliated granodiorite and other foliated granites, respectively. And amphiboles are calcic hornblende in Foliated hornblende biotite granodiorite, and riebeckite in Daegang foliated granite. In differentiation index(D. I.) and Larsen index(L. I.), Daegang foliated granite, Foliated two mica granite and Samori foliated granite which belong to granite are 83.12-95.54 and 25.86-29.05 and Foliated hornblende biotite granodiorite and Sunchang foliated granodiorite of diorite to granodiorite are 54.99-78.54(D. I.) and 6.48-21.01(L. I.). Harker and AMF diagrams plotted from foliated granites show that the granites are product of calc alkali rock series orignated from co-magma. Characteristic foliation of foliated granites fromed by ductile deformation at deep zone of dextral strike slip fault. Foliated granites are considered as a series of differentiated product of Triassic Igneous activity of Songrim disturbance. According to REE, (La/Lu) and Eu/Sm, Foliated hornblende biotite granodiorite and Sunchang foliated granodiorite are correspond to granodiorite, and other foliated granites are monzo-and syeno-granite. Foliated granites having 0.20-0.01 of Em/Sm ratio are plutons emplaced by the tectonic setting in continents and continental margin.

Igneolls rocks of the Hamyang area consist of Hamyang foliated granites and hornblende diorite. Hamyang foliated granites are classified into four rock types in terms of mineral composition and texture. The four rock types are foliated hornblende biotite granodiorite, foliated porphrytic granodiorite, foliated fine biotite granodiorite and foliated leuco granite. Petrochemical data of these rocks suggest that Hamyang foliated granites is calc-alkali rock series of differentiated products of cogenetic magma by fractional crystallization. Igneous rocks of studied area correspond to I-type, peraluminous and calc alkali rock series. Rb-Sr age and $Sr^{87}/Sr^{86}$ initial ratio for foliated prophrytic granodiorite is $200{\pm}Ma$and $0.711{\pm}0.0037$, respectively. K-Ar(hornblende) age of hornblende diorite is $179{\pm}9Ma$. These data come to an coincidence with Igneous activity of South Korea which were proposed by O.J. Kim(1975), that is, they correspond to Hamyang foliated granites of products of Songrim Disturbance, and to hornblende diorite of Daebo Orogeny.