Geology+-+Rock+Tumbler

=Rock Tumblers...= ==== A rock tumbler is used to shape and polish rocks to bring out the natural features of the stone. The most common type of rock tumbler is a rotary drum====

than the ocean (and rivers), but it still takes several weeks to go from rough rocks to polished stones.
====This exercise is about looking at rocks and sorting by clast/crystal size and by the presence/absence of layering. Whether the rocks are sedimentary, metamorphic, or igneous has not been looked at yet. The student has to first be able to look at the rocks and notice the differences. Interpreting the ====
 * [[image:P1320419-002.JPG width="331" height="250"]] || [[image:P1130945.JPG width="325" height="242"]] || [[image:P1130948.JPG width="313" height="238"]] ||

observed features comes later in the learning process.

 * [[image:P1320335.JPG width="328" height="256"]]

The rocks look very mucky when they are covered in grit and rock powder. These rocks have come from Riverton and Te Anau shores.
|| ====Jessica is taking the rocks out of the bin and looking at how they might be sorted into groups. Cheyenne====

is spraying the rocks with water so that their structure is more easily seen.
|| ====These rocks are sorted according to the children’s criteria. Notice how they have put rocks with large crystals; rocks of similar colours; rocks with layers; and rocks that are very fine-grained together in groups.==== ||
 * ====[[image:P1320344.JPG]]This rock is from Te Anau and shows very distinct layering. Layers are tricky as they may be formed from a number of geological processes. In this case, these layers look like they may have been formed====

due to a volcanic eruption.
|| ====This rock is also from Te Anau and is also layered. Notice that there is a fracture (micro-fault) across the centre which has offset the layers. The fracture has since been healed by quartz.==== || ====We are discussing what to look for in these rocks.==== || =The Results ...=
 * [[image:P1320348.JPG]] || **Step 1:**

The bottom row rocks have some form of layering.
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 * [[image:P1320355.JPG]] || ====**Step 2:**====

The completed rows.
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 * [[image:P1320352.JPG]] || ====**Row Sections - Left :**====

In the bottom row there are high-grade schists and gneisses.
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 * [[image:P1320353.JPG]] || ====**Row Sections - Middle:**====

rocks layered with quartz bands in the bottom row.
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 * [[image:P1320354.JPG]] || ====**Row Sections - Right:**====

rocks may show very distinct layering.
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