Geology+2009

=Rock Workshops, 2009= Geologist: Mark Beaton || ||  || =Finding and Folding a Fault...= Paper models in two parts are being made showing different sedimentary layers and landscape features. Students are discovering how blocks of land along fault lines slide against,and up and down each other, shifting the layers accordingly to make many landscape features around the school. ...to match the perfectly constructed models with the not so perfect real thing! || =Exploring Sand....= = = Using the Dinolite, Zac and Jessica discovered that sand from the sand pit was like a mini-collection of tiny rocks. With Mr Beaton's help, they decided to explore sands from different beaches. Making the well slides..... || Jessica and Zac each made 4 double-well slides of 8 sands.
 * [[image:P1060739.JPG width="202" height="285"]]
 * [[image:P1140862.JPG width="200" height="163"]] || [[image:P1140856.JPG width="186" height="165"]] || [[image:P1140922.JPG width="199" height="145"]] ||
 * [[image:P1140924.JPG]] || [[image:P1140925.JPG]] ||
 * [[image:P1140955-2.JPG]] || ==Hmm... which model is the Maungatuas?==
 * Soon a field trip with a //tricky// aim...**
 * [[image:P1140590.JPG]]

They discovered that: coastline because the wave action drifting along the shore drops the heavier sands first and the finer sands last. Otago Peninsula, may add different minerals to the sands as they pass by. Tiny bits of granite may mean the tiny bits of sand on the beach started off as mountains in Fiordland! || Spooning out the sand samples || Putting rock glue in the slide well || Adding sand to the glue in the well || Blowing off the surplus sand || Prepared and left to dry overnight || All samples ready to be explored with the microscope ||
 * Sands from different beaches are usually different.
 * Sometimes the difference shows up in grain size.
 * Sands tend to get finer at each beach up the
 * Pieces of land sticking out into the sea like the
 * Sometimes sand comes from entirely different rocks.
 * [[image:P1140594.JPG width="321" height="228"]]
 * [[image:P1140597.JPG]]
 * [[image:P1140600.JPG]]
 * [[image:P1140624.JPG width="265" height="307" align="left"]]

Different colours show different minerals..... || ...different shapes... || rock from somewhere close by e.g garnet Zac and Jessica then made a Sand Comparitor to compare grain sizes in their rock samples. The sands are arranged in grain size order from very fine sand to fine pebbles. || Preparing the Grain Size Comparitor ready to take into the field... || The completed Grain Size Comparitor: The front held by Zac, showing the sand grain samples in size order. Jessica is showing the back - a pictorial guide. ||
 * [[image:P1140626.JPG]] || [[image:P1140633.JPG width="323" height="244"]] ||
 * [[image:P1140631.JPG width="328" height="243"]] || [[image:P1140627.JPG width="328" height="249"]] ||
 * Grain shapes:
 * **round** grains show long-distance travel
 * **angular** grains show the source is close by
 * **pitted** grains show a wind-blown environment
 * Crystal faces:
 * Many crystal faces (//euhedral//) suggest a hard igneous
 * Some crystal faces (//subhedral//)
 * No crystal faces (//anhedra//l) - perhaps well-worn || [[image:P1140641.JPG]]
 * [[image:P1140709-1.JPG width="341" height="231"]]

Jessica's Stunning Siltstone.....

 * [[image:P1140259-1.JPG align="center"]]

Jessica's Riverine Siltstone
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These rocks are found only in East Kimberly, Western Australia.
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.
 * [[image:riverRock.jpg width="273" height="185"]] || =The Patient Process of Polishing Rocks!=

The rocks came from the Te Anau and Riverton areas
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 * ====[[image:rock_tumbler.jpg width="334" height="296"]]====

The Rotary Drum Rock Tumbler
|| ==== ==== =Rock Tumblers...=

to polished stones!
|| =Opening the tumbler...= = = ||  || =The process.....= First, the rocks are put into the tumbler with coarse grained grit. Rubber pellets are added to cushion the rocks and prevent chipping. The grit wears dow the rock's surface. It is made from silicon carbide.
 * [[image:P1130944.JPG width="272" height="199"]] || [[image:P1130945.JPG width="276" height="204"]] || [[image:P1130948.JPG width="260" height="194"]] ||  ||
 * [[image:P1130968.JPG width="271" height="188"]]

After several days have passed, the rocks are checked. Then they are washed and tumbled with a smaller grained grit. This process is repeated several times, with the grit getting finer each time, until the stones are ready for polishing. The finest polishing grit is used in the last step to give the rocks a glossy finish. || =Watch this space....=
 * [[image:polished-rocks-mixed-large.jpg width="269" height="208"]] || [[image:P1130959.JPG width="265" height="199"]] || [[image:P1130958.JPG width="259" height="196"]] ||