The Contact Between the Granitic Rocks and the Cardup Series 
AT Armadale. 45- 
Tlie characteristic ophitic lo sub-ophitic texture of the quartz-dolerites 
is always developed, although somewhat obscured by uralitisation and epi- 
dotisation (ftgure 5A). A typical s])eciinen from the large dyke striking 
south-east from the Roads Board quarry is a greenish, medium even grained 
rock, which consists of pale green uralite, epidote, zoisite, leiicoxene, quartz 
and minor accessories including a little brown hornblende, biotite and apatite. 
A relict ophitic relation is visible between the uralitie amphibole plates and 
the zoisitic aggregates replacing plagioelase prisms, the only other notice- 
able textural feature being the angular patches of (piartz and micropegmatite 
(in which the felspar is represeiitetl by turbid zoisitic aggregates). 
The uralite is the most abundant constituent, occurring in plates up to 
1 mm. diameter. It is a pale greenish tibrous variety with weak pleo- 
chroism, X very pale greenish (almost colourless), Y pale green, Z pale 
green, absorption X Y = Z, extinction Z /\ e = 16° and (— ) 2V larae. 
It is often dusted with magnetite inclusions. Xo relict pyroxene is visible, 
nor has any been noted in any of the basic intrusive rocks of this area. In 
the vicinity of the quartz and micropegmatite areas the uralite shows a 
further change to pale green, weakly pleochroic, optically positive chlorite 
and more rarely to brownish hornblende. 
The plagioelase is represented by granular aggregates of zoisite, 
epidote and line granular plagioelase. Ilmenite has been replaced entirely 
by fine granular leucoxene which occurs in areas up to 1^^ mm. diameter 
in which the skeletal structure of the original ilmenite is preserved. Occa- 
sionally the leucoxene is recrystallised to sphene, which occurs in rounded 
grains with central iron ore inclusions. 
The quartz and micropegmatite areas in this rock, up to V 2 Rhu. dia- 
meter, are similar to those of the normal quartz-dolerites except that the 
felspar is replaced by fine granular zoisite. These quartz and micropegma- 
tite areas are jxmetrated by slender prisms of a]iatite. In specimens from 
the centre of this same dyke the micropegmatite areas vary in size to iy 2 
mm. diameter and the presence of brownish hornblende in its vicinity is 
more noticeable. 
1. 
Table IY. 
2. 
3. 
4. 
SiO^ 
... 48-83 
49-13 
40-22 
50 • 52 
Al-A ... 
... 13-46 
13-13 
12-62 
13-76 
Fe,A ... 
2-88 
3-65 
3-16 
3-87 
FeO 
10-29 
8-95 
11-09 
8-50 
MgO ... 
8-03 
7-64 
6-42 
5-42 
CaO 
... 11*95 
H-84 
10-59 
9-09 
XaoO ... 
1*32 
1-72 
1-86 
2-42 
K.>6 
0-50 
0-16 
0-30 
0-96 
H..O+ ... 
1-39 
1-72 
2*24 
1-51 
H.>0— ... 
0*08 
0-04 
0-12 
0-76 
CO., 
• • • • « • 
• • • 
Nil 
0-58 
TiO", 
1*24 
1-27 
2-00 
2-39 
P.,0, ... 
0-07 
014 
0-09 
0*26 
MnO ... 
0*18 
0-15 
0-33 
0-16 
BaO 
Nil 
Nil 
0-03 
FeS., 
Tr. 
0-45 
0-22 
0-06 (S) 
Cr.,0., ... 
0-08 
... 
Tr. 
Tr. 
v.;o, ... 

... 
Tr. 
0-05 
100-30 
99-99 
100-26 
100-34 
Analyst : 
R. T. Prider. 
R. T. Prider 
_ 
