710 STEINAR FOSLIE 
While the composition of the quartz-norite is pretty uniform 
throughout, the marginal norite varies considerably. The analysis 
No. 3 represents a type very rich in hypersthene, analysis No. 5 a 
type rich in plagioclase, and analysis No. 4 a mean type. 
Normal Norite, No. 3 Quartz-Norite, No. 6 
Weight Percentage Weight Percentage 
Quartz ee caer ee eee None DT 
Orthoclase.ke sc eee None 4.7 
Plasioclase este nl eee 20.0 (ca. AbyAngo) | 59.2 (Ab;;An,) 
Diallagem. ee wee re 4.6 16.6 
Fy PersEnenene ee ane Aree 50.2 II.o 
Bigtitehes seus con eee ee ee age Buon 
Amphibole, secondary....... 16.1 Very little 
Magnetite+-ilmenite........ 1.4 Dth 
IPAViaAOONEDs cao po noose aeons 0.2 0.2 
Rutiless Fs.) sae eee oes 0.2 None 
AMO tala) A Spore) ony nat 100.0 100.0 
* A special case. Generally there is more biotite in the quartz-norite than in the 
normal norite. 
By the aid of the seven analyses stated above we may calculate 
the mean composition of the four main groups of .rocks occurring 
in the field. They are as follows: 
Oltiethenins Marginal Zone | Central Field 
litic Grani 
Rocks of Nommal Oh uaz 2 Dikes Ee 
SION Secu Reo wes ere 41.53 50.80 55-90 72.20 
il Bt @ eran eatin CET 0.10 0.44 0.45 0.39 
PeN 0 Se ete Ny ne neem 5-20 16.99 17.50 Tne 
1 GH O ger eS AG AH eel wet Ocoee 2.40 0.44 0.08 0.55 
DO Te ie ato apie te rela ee 9.64 6.47 6.97 2.00 
IMO 5 ore par TaN 0.24 0.14 0.09 0.03 
NEC O) Aue Oi. Cert san aap Fhe 36.08 13.20 5-98 I.03 
CaO ees Sie Rae ee ete 1.85 8.43 8.32 2.60 
Ba@eeiinin coed ine enews peas None Trace Trace 0.02 
Nat OR a neraatetn ieee 0.59 1.43 Dis 2. Isis 
RON at a tae ero eS ©.49 o.60 1.50 3.78 
a Beis cbakercr comet ae epee 0.07 0.03 ©.05 0.08 
PAO eae Neen Msi ccm arty cts Has ae alee se @569) . eaunone idee eee 
a eres Cay ae rata ee eh ©. 20 0.06 0.05 Trace 
Cie OF ona Se raccaatie te malar 0.08 0.09 None. | {235 aeanee 
These variations are illustrated in sae diagram of the differ- 
entiation processes (Fig. 3). 
