part 4] 



PETROLOGY OF THE AKXAGE DISTRICT. 

 Table II. — The Norite and other Gabbeos. 



457 





V. 



B. 



C. 



D. 



E. 



Si0 2 



52-04 

 0-66 



16-31 

 0-06 

 0-05 

 001 

 7-98 

 0-14 



nt. fd. 



trace 

 7-24 



11-70 

 0-89 

 1-82 



trace 

 006 

 0-51 

 0-08 

 0-02 

 051 

 0-46 



47-52 

 3-06 



15-65 

 0-75 



10-90 

 0-27 



... 

 10-83 

 6-35 

 056 

 255 



| 0-63 



0-28 



50-16 

 1-64 



18-51 

 1-88 



9-29 

 0-14 



7-90 

 5-97 



0-80 



2 - 72 



| 0-76 

 0-23 



50-23 

 1-15 



1640 

 239 



7-64 

 0-12 



8-92 

 8-54 

 0-81 

 254 



0-68 

 0-22 



48-84 

 1-35 



15-90 

 523 



6-30 

 0-29 



915 



6-38 

 146 

 305 



I 1-60 

 0-45 



Ti0 2 



Al.Oj 



Fe-,0 3 



Cr 2 Oj 



V0O3 



FeO 



MnO 



(CoNi)O 



BaO 



CaO 



MgO 



K 2 



NaoO 



Li.,0 



HoO at 105° C. 



H 2 above 105° C. ... 



P.,0 5 



FeS 9 



Fe;S 8 



CO. 





Totals 



100-54 



99-35 



100-00 



99-64 



100-00 













V. Norite of the Arnag-e Mass. Railway-cutting, 600 yards south of Mill 



of Inkhorn, Arnage, Ellon. Anal. E. G. Radley. 

 Average for chief oxides of six gabbros of the Huntly and Insch Masses : see 



' Explan. of Sheets 86 & 96 ' Mem. Geol. Surv. Scot. 1923, Chap. VI. 

 Average of all norite (seven analyses) ; R. A. Daly, ' Igneous Rocks & their 



Origin ' 1914, p. 27. 

 I). Average of 44 rocks, designated norite, in Dr. H. S. Washington's ' Chemical 



Analyses of Igneous Rocks ' U.S. Geol. Surv. Professional Paper 99, 1917. 

 E. 'Primary basaltic magma' of R. A. Daly, 'Igneous Rocks & their Origin' 



1911, p. 315. 



i; 



C. 



V. The Contaminated Hocks. 



Introduction. — Between the kernel-norites and the true 

 country-rocks is a zone several miles wide made up of the rocks 

 here styled contaminated. This zone is believed to lie above 

 the norite-sheet exposed in the kernels (see tig. 2, p. 452), and 

 represents the modification of the initial magma by incorporation 

 of country-rock. The chief characteristics of the contaminated 

 rocks are four, namely: — 



(i) They are extremely rich in xenoliths. 



(ii) They are variable in grain and type-distribution, 

 (iii) They have a more or less pronounced fluxional structure. 



(iv) They vary in composition from g - abbroic rocks to rocks of granitic 

 type, and contain minerals — the chief of which are cordierite, spinel, 

 and gurnet — usually considered abnormal in igneous rocks. 



The area covered by these contaminated rocks at Arnage is 

 about 10 square miles. Their margins against the country-rocks 



2 i2 



