Journal of the Federated Malay States museums - Sabrizain.org
Journal of the Federated Malay States museums - Sabrizain.org
Journal of the Federated Malay States museums - Sabrizain.org
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
32 <strong>Journal</strong> <strong>of</strong> <strong>the</strong> F.M.S. Museums. [Vol. VII,<br />
Mining Industries <strong>of</strong> Ulu Pahang," p. 59, 60) which are<br />
believed to be <strong>of</strong> <strong>the</strong> same age as <strong>the</strong> granite <strong>of</strong> that range and<br />
possibly to owe <strong>the</strong>ir distinct composition to a mixture <strong>of</strong> a<br />
basic magma with that <strong>of</strong> <strong>the</strong> granite. Some <strong>of</strong> <strong>the</strong>se rocks,<br />
however, contain pyroxene. There is none in <strong>the</strong> Pulau<br />
Pisang pebble nor is <strong>the</strong>re any reason to believe that <strong>the</strong><br />
hornblende is derived from pyroxene, and a rock <strong>of</strong> this nature<br />
might consolidate at a shallow depth from a part <strong>of</strong> a<br />
hornblende-granite magma poor in quartz. There is a quantity<br />
<strong>of</strong> white opaque matter showing a trace <strong>of</strong> crystal outline<br />
which is probably a decomposed titaniferous mineral.<br />
j. This is a dark pebble, shown by <strong>the</strong> thin section to be<br />
altered volcanic ash rich in quartz and with orthoclase and<br />
soda-plagioclase as felspars. Alteration is proved by <strong>the</strong> hard<br />
compact nature <strong>of</strong> <strong>the</strong> rock and <strong>the</strong> presence <strong>of</strong> a secondary<br />
mineral, in minute grains. It may be zoisite.<br />
4. Ano<strong>the</strong>r altered ash similar to 3. The secondary<br />
mineral is probably epidote.<br />
5. A finer grained ash, full <strong>of</strong> a granular mineral, probably<br />
secondary epidote.<br />
6. A rock with much secondary epidote which obscures<br />
its original nature. It may have been sandstone.<br />
7. A pale grey pebble <strong>of</strong> very fine but hard texture. It<br />
is impossible to say anything with certainty about its mineral<br />
composition even after examination under a 1/12" oil immersion<br />
objective. It is probably altered shale with minute granules<br />
<strong>of</strong> epidote.<br />
8. A pebble closely resembling black chert <strong>of</strong> <strong>the</strong> Chert<br />
Series, <strong>the</strong> resemblance being confirmed by <strong>the</strong> section. The<br />
secondary minerals are epidote, some forming minute veins,<br />
and a very finely fibrous mineral <strong>of</strong> which nothing definite can<br />
be said but which is probably an amphibole. There is no trace<br />
<strong>of</strong> radiolaria.<br />
9. A banded pebble showing black and grey rock. Both<br />
are very fine grained but <strong>the</strong> black rock is certainly altered<br />
chert, while <strong>the</strong> grey is ei<strong>the</strong>r shale or fine ash.<br />
ro. This is one <strong>of</strong> <strong>the</strong> two specimens mentioned by Mr.<br />
Kloss and is like No. 7. It shows stratification. Thin sections<br />
<strong>of</strong> <strong>the</strong> rock point to it being fine shale full <strong>of</strong> granular epidote.<br />
11. The o<strong>the</strong>r specimen mentioned by Mr. Kloss consists<br />
<strong>of</strong> alternating bands <strong>of</strong> black and grey rock, <strong>the</strong> latter having a<br />
slight buff tint. The grey bands resemble 7 and 10 and mav<br />
be ei<strong>the</strong>r altered shale or fine ash. The black bands are<br />
altered chert and fine black shale. The secondary minerals<br />
<strong>the</strong>y contain are epidote, <strong>the</strong> fibrous mineral seen in No. 8,<br />
which, in one slide, has a distinct greenish tint, and brown<br />
mica.