186 



AKT. 2. — B. KOTÔ 



NEOGRANITES 



Marginal Facies of Laccolitli 



Effusive Forms 



13 



1. Quartz-porpliyry (quartz-tsing- 

 tauite).— Phenocrysts of quartz, 

 bipyramidal or corroded, and 

 of ortlioclase, are set in the 

 microgranitic, sometimes mic- 

 ropegraatitic groundmass. 



2, Tsingtauite. — Ortlioclase is the 

 only phenocryst which is im- 

 bedded in a microgranitic 

 groundmass (Rinne). This 

 rock has thus far not been 

 observed by the writer in 

 Korea. 



3. Masanite'^ (graniteporphyry). — 

 Plien ocry sts of plagioclase, 

 usually zonal-structured, and 

 often myrmekitic on periphery; 

 those of quartz, bipyramidal 

 or corroded, — both are set in 

 a tine granitic or micropeg- 

 matitic groundmass. If the 

 phenocrysts of quartz occur in 

 addition to those of plagioclase, 

 the rock may fitly be called 

 the quirtz-masanite. 



O 



4. Grano-masanite 

 nite). 



(Aplite-gra- 



1. Orthoclase-quartz-felsophyre. — 

 Groundmass is pinkish, micro- 

 felsitic, showing flowage struc- 

 tiu-e. It is sometimes micro- 

 pegmatitic. The phenocrysts 

 of quartz and orthoclase are 

 imbedded in the matrix. The 

 quantity of quartz is variable, 

 and the rock is often found in 

 transition to the next variety. 



2. Orthoclase-felsophyre. — Pheno- 

 crysts of orthoclase are set in 

 matrices of the same kinds as 

 in the preceding. 



3. Plagioclase - quartz -felsoph yre 

 (crystal-porphyry). — The matrix 

 is the same as in the two 

 preceding. 



4. Eutectofelsite. 



1) So named becaxise it is typically exposed in the Kn-ryong Copper Lline near the port 

 of Ma-san-pho (See ante, page 22). 



