142 
PACIFIC SCIENCE, VoL XXI, January 196? 
TABLE 5 
Densities and Magnetic Susceptibilities of Representative Rocks of the Tophouse District 
DENSITY 
❖ 
ROCK 
TYPE 
FORMATION 
MAGNETIC 
SUSCEPT., 
CGS UNIT 
X10-6 
DRY 
WET 
PART. 
3.30 
3.30 
3.30 
0 
dunite 
Wairau ultramafic mass 
3.30 
3.30 
3.30 
0 
dunite 
Wairau ultramafic mass 
2.93 
3.02 
3.21 
9 
weathered dunite 
Wairau ultramafic mass 
3.19 
3.19 
3.19 
0 
pyroxene peridotite 
Wairau ultramafic mass 
206 
3.20 
3.20 
3-21 
0 
pyroxene peridotite 
Wairau ultramafic mass 
247 
3.33 
3.33 
3.34 
0 
dunite 
Wairau ultramafic mass 
3.34 
3.34 
3.35 
0 
dunite 
Wairau ultramafic mass 
3.32 
3.32 
3.32 
0 
harzburgite 
Wairau ultramafic mass 
204 
3.11 
3.13 
3.18 
2 
harzburgite 
Wairau ultramafic mass 
3.24 
3.25 
3.27 
1 
weathered dunite 
Wairau ultramafic mass 
3.26 
3.27 
3.30 
1 
pyroxene peridotite 
Wairau ultramafic mass 
220 
3.24 
3.24 
3.25 
0 
pyroxene peridotite 
Wairau ultramafic mass 
2.68 
2.68 
2.68 
0 
hard serpentinite 
Wairau ultramafic mass 
2.83 
2.84 
2.84 
1 
hard serpentinite 
Wairau ultramafic mass 
2840 
2.56 
2.58 
2.61 
2 
hard serpentinite 
Wairau ultramafic mass 
I960 
2.66 
2.66 
2.67 
0 
hard serpentinite 
Wairau ultramafic mass 
1300 
2.92 
2.94 
2.97 
2 
serpentinized dunite 
Wairau ultramafic mass 
2.57 
2.60 
2.66 
3 
soft serpentinite 
Wairau ultramafic mass 
940 
2.22 
2.34 
2.53 
12 
soft serpentinite 
Wairau ultramafic mass 
1435 
2.88 
2.88 
2.89 
0 
amphibolite 
Wairau ultramafic mass 
2.88 
2.89 
2.91 
1 
amphibolite 
Wairau ultramafic mass 
2.91 
2.92 
2.93 
1 
amphibolite 
Wairau ultramafic mass 
2.87 
2.89 
2.92 
2 
amphibolite 
Wairau ultramafic mass 
430 
2.92 
2.93 
2.95 
1 
red volcanic breccia 
Wairau ultramafic mass 
2.81 
2.84 
2.90 
3 
spilite 
2.86 
2.87 
2.91 
1 
spilite 
125 
2.93 
2.94 
2.95 
1 
dolerite 
66 
2.79 
2.80 
2.82 
1 
red and green schist 
120 
2.76 
2.78 
2.80 
2 
green schist 
2.99 
2.99 
3.00 
0 
spilite 
Brook Street volcanics 
2.89 
2.90 
2.92 
1 
spilite 
Brook Street volcanics 
2.90 
2.90 
2.91 
0 
spilite 
Brook Street volcanics 
1000 
2.78 
2.80 
2.84 
2 
volcanic agglomerate 
Brook Street volcanics 
93 
2.61 
2.64 
2.69 
3 
volcanic tuff 
Brook Street volcanics 
38 
2.68 
2.69 
2.70 
1 
hard limestone 
Rangitoto formation 
0 
2.67 
2.68 
2.69 
1 
grey calcareous 
Rangitoto formation 
0 
sandstone 
2.60 
2.63 
2.67 
3 
calcareous sandstone 
Rangitoto formation 
0 
2.64 
2.67 
2.71 
3 
grey slate 
Greville formation 
22 
2.63 
2.68 
2.75 
5 
grey slate 
Greville formation 
20 
2.68 
2.71 
2.77 
3 
grey slate 
Greville formation 
20 
2.74 
2.77 
2.82 
3 
red and green slate 
Waiua formation 
2.34 
2.47 
2.69 
13 
tuff 
Waiua formation 
40 
2.71 
2.73 
2.75 
2 
metasomatized volcanics 
Waiua formation 
58 
2.82 
2.85 
2.90 
3 
volcanic sandstone 
Stevens formation 
230 
2.92 
2.95 
2.94 
1 
volcanic sandstone 
Stevens formation 
50 
2.70 
2.72 
2.77 
2 
volcanic siltstone 
Stevens formation 
2.67 
2.71 
2.79 
4 
volcanic siltstone 
Stevens formation 
50 
2.61 
2.63 
2.66 
2 
greywacke sandstone 
Alpine facies 
(Raglan series) ? 
2.62 
2.62 
2.64 
0 
greywacke sandstone 
Alpine facies 
(Raglan series)? 
