Five species of graptolites were discovered from the Jigunsan Shale of Taebaeg area, Korea. They are herein described as Archiclimacograptus riddellensis (Harris, 1924), Pseudamplexograptus distichus(Eichwald, 1840), Hustedograptus teretiusculus(Hisinger) sensu Jaanusson, 1960, Hustedograptus vikarbyensis (Jaanusson, 1960), and Hustedograptus sp. The graptolite assemblage from the Jigunsan Shale corresponds to those of the Pseudamplexograptus distichus zone in the Baltic and German areas and the geologic age of graptolites bearing beds of the Jigunsan Shale might be late Middle Llanvirn.

The principal consisting rocks of study area are Precambrian metasedimentary bedrocks, Cambro-ordovician sedimentary rocks and Samhwa granite which have intruded these metasedimentary and sedimentary rocks. The reddish K-feldspar bearing Samhwa granite presettts miarolitic texture and graphic intergrowth between quartz and K-feldspar. The granite, homogeneous in chemical composition of major elements, belongs to Calc-alkali rocks of subalkali series. According to AMF diagram, the granite was crystallized at the latest stage of the differentiation of magma. The Samhwa granite belongs to I-type granitoids and magnetite-series granitoids. Especially, this granite is thought to be crystallized in the epicrust with high oxygen fugacity. The Samhwa granite has similar characteristics to masanite of cretaceous granitic rocks of Gyeongsang basin in the petrological and petrochemical properties. The biotite age of the granite by K-Ar age dating is 50.1±1.5. Finally, contact metamorphic zone of limestone by granite intrusion contains distinct minerals such as diopside, brucite, tremolite and muscovite, which indicate low temperature metamorphic grade.

太白山地區의 主要 망간鑛床에서 産出하는 酸化망간 鑛物들은 一次的으로 생성된 炭酸망간 또는 珪酸망간의 表成風化作用에 依하여 生成되었다. 이들 酸化망간 鑛石의 生成에 관여된 地質作用에는 溶解作用, 酸化作用, 運搬作用, 沈澱作用, 晶出作用 및 再結晶作用 等이 있다. 그러나 箇箇의 酸化망간 鑛物 生成은 交代作用, 溶液으로부터의 晶出作用 및 固體狀態에서의 晶出, 및 再結晶作用 等에 依하여 이루어졌다. 이들 鑛物生成作用에 依하여 多樣한 名種 鑛石의 組職이 形成되었으며, 母鑛石의 鑛物組成과 風化環境에 따라 特徵的인 鑛物 및 鑛物共生關係가 形成되었다. 그러나 一般的으로 風化殘留鑛床 중의 酸化망간 鑛物들은 Mn2+→Mn3+→Mn4+의 方向으로 生成되었다.