Some Kyanite-bearing Rocks from the Eastern Goldfields, 
W estern Australia. 
23 
grade nietamorphie eoiiditions which have produced in them some internal 
recrystallisation often with development of schistosity, but without any 
marked mineralogical reconstitution. 
Finally the signihcant association of both the Camel Humps and the 
Mt. Leonora rocks with horizons of banded ferruginous (piartzite should be 
once more noted. They may reiiresent merely more argillaceous and non- 
ferruginou.s zones in such handed quartzites, or possibly portions of beds in 
which the iron content was largely leached away before metamorphism. 
It is interesting' to note; that such minerals as andalusite and sillimanite 
have been recorded a.s contact alteration products of banded ironstones near 
Bulawayo and Salisbury in S{)uthern Rhodesia. (21). 
Mt. Kenneth and QuinKs Rocks. 
The Mt. Kenneth and Quinn^s metamorphi('s bear a striking similarity to 
each other in their chemical composition. The principal mineral differences 
are in the aluminium silicates, the Quinn’s rocks containing i)redominant 
andalusite, whilst of the Ml. Kenneth types, one specimen (C) carried 
abundant kyanite while the other (D) has suffered but weak dynamic meta- 
morphism with r-ecrystallisation of white mica under inapjn'eciable tem- 
peratures, and no alumino-silicate has been formed. These rocks differ from 
the Alt. Leonora and Camel Humps types mainly in their lower alumina 
content and greater pi’oportions of ferrous iron, magnesia, and combined 
water. These ditferences are i-efleeted in the much lower ])ercentag’e of the 
aluminium silicate minerals and the relHtiv(‘ abundance of such minerals as 
chlorite, muscovite, and to a lesser extent, biotite. A noticeable featurf^ of all 
these rocks is their remarkably low lime content. 
The Mt. Kenneth and Quinn’s rocks both have the general appearance, 
texture and mineral compositioiq of original medium-fine grained, impure 
argillaceous grits, which since compaction have suffered some crushing under 
shearing pressures, and with increasing temperatiu’es have reached an early 
stage of recrystallisation. In the case of one of the Mt. Kenneth rocks 
kyanite has been j)roduced as a result of a continuation of shearing stress at 
the increased temperature. This stress must have been largely absent during 
the gi’owth of andalusite in the Quinn’s rocks but some retrogj’essive altera- 
tion of this mineral to chlorite and muscovite in specimen F suggests a later 
increased pressure during cooling. 
SUMMARY. 
During the 1939 field season of the Geological Survey, an oc(mn'encc of 
kyanite-bearing quartz schist, a type hitherto unrecorded from the district, 
was noted amongst the hills of the Camel Humps, north of lan'ei'ton, Mt. 
Margaret Goldfield. This rock is a fairly high-grade regionally metamor- 
j)hosed sediimmt which forms portion of an horizon of banded ferruginous 
quartzite. In bf)th its field occurrence and its petrography, it is closely 
comparabh* with an occurrence of metamorphosed sediments at ^Mt. Leonora, 
Mt. Margaret Goldfield. 
Mt. I.eonora voek is i UHHlominantly an andalusite-hearing (piartzite or 
(iuartz schist in which the andalusite has I'eached only an early stage of crys- 
talloblasti(' development. Although some siiecimens contain minor quantities 
of the higher grade stress minei’als kyanite and sillimanite, mineral eomposion 
