02.01.2021 Views

The Earliest Inhabitants: The Dynamics of the Jamaican Taino

by Lesley-Gail Atkinson

by Lesley-Gail Atkinson

SHOW MORE
SHOW LESS

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

YOUNGER<br />

GROUP<br />

OLDER<br />

GROUP<br />

Limestone<br />

Sediments o<strong>the</strong>r than limestone and<br />

some volcanic lavas<br />

Sediments<br />

Lavas, sediments and igneous<br />

intrusions<br />

Metamorphic rocks<br />

1. St James<br />

2. Trelawny<br />

3. St Ann<br />

4. St Mary<br />

5. Portland<br />

6. Hanover<br />

7. Westmoreland<br />

8. St Elizabeth<br />

9. Manchester<br />

10. Clarendon<br />

11. St Ca<strong>the</strong>rine<br />

12. St Andrew<br />

Figure 9.1 Simplified geological map <strong>of</strong> Jamaica showing parishes<br />

in hand specimens. It is <strong>the</strong>refore not usually possible to say whe<strong>the</strong>r <strong>the</strong> original<br />

rock was, for instance, lava, a conglomerate or a sandstone before it was<br />

metamorphosed. Sometimes on a sawed section or under <strong>the</strong> microscope it<br />

may be possible to see a few relict structures or textures indicative <strong>of</strong> its origin.<br />

Most <strong>of</strong> <strong>the</strong> metamorphic rocks <strong>of</strong> Jamaica have not undergone a major<br />

alteration and can be considered to be only lightly metamorphosed. <strong>The</strong>y<br />

appear as extremely fine-grained massive rocks lacking structure. Indeed, <strong>the</strong><br />

crystals are so small that very <strong>of</strong>ten it is difficult to identify <strong>the</strong>m under <strong>the</strong><br />

microscope.<br />

<strong>The</strong> most common <strong>of</strong> <strong>the</strong>se rocks are coloured green, and <strong>the</strong> term “greenstone”<br />

seems as good as any. Less common is a black-coloured variety (“blackstone”),<br />

which occurs interlayered with <strong>the</strong> greenstone; where <strong>the</strong> two occur<br />

in cliff faces, <strong>the</strong>y are usually strongly folded. Marble (metamorphosed limestone)<br />

also occurs interlayered with <strong>the</strong> greenstone – for example, at <strong>the</strong><br />

quarry at Serge Island Estate in <strong>the</strong> east arm <strong>of</strong> <strong>the</strong> Morant River, sou<strong>the</strong>rn<br />

Blue Mountains. A higher degree <strong>of</strong> metamorphism results in a coarsergrained<br />

rock which shows a foliation <strong>of</strong> crystals. Such a rock is called a schist<br />

and tends to split easily.<br />

134 T HE E ARLIEST I NHABITANTS

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!