Geology+2008

=Geology 2008= Students have the opportunity to engage with Mark once or twice a week in the Allen Centre. The rock section of the Museum is growing rapidly, with specimens delivered by curious students on an almost daily basis. Mark has assembled a camera stand which can be used in conjunction with the digital microscope. He has made polished cross-sections of a number of rocks to illustrate their internal structure, and uses them to illustrate various concepts with the students. In this session he introduced children to the concept of graded bedding of sediment. Mark, photographing rocks for cataloguing and identification. || || Timothy, Leo, Tyler and Matthew exploring rocks using the digital microscope. || Pebblestone showing large to small sediment,stacking into **graded bedding.** Look at the different angles along the rock sediment planes. || A mixture of rock types and sizes - a **polymict**. || Different rounded rock types and sizes - a **conglomerate.** (Te Anau) || Gneiss (metamorphic) showing black biotite in layers. || Greywackeshowing poorly graded sediment in two bedding planes. || In the next session, children were introduced to sedimentary, metamorphic and igneous rocks. They learned how sediment size grades from larger to smaller along a river as it flows downto the sea. They also ldiscovered that the shape and size of sediment alters with depth. By exploring the behaviour of a volcano, they looked at the difference between rocks on the surface, down through rocks in the metamorphic zone, to rocks formed in the zone of melting.
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 * Students matched rock specimens to a diagram.

The rocks illustrated different sediment size in a river - larger conglomerates where the river begins at the top of the mountain, grading through medium sized pebblestones to the fine sediments where the river finally meets the sea.

They also matched rocks to their places of formation - deep beneath, inside and outside a volcano. || ||

=Plate tectonics= Using the context of New Zealand and the way it was formed, students were introduced to plate tectonics. The aim was to give them a general idea of how mountain ranges are formed and the types of rocks associated with their formation. Students used a plastic model of sliding plates to illustrate the concept, making appropriate clay structures to slide or stretch across the "ocean floor". Hopefully they will be able to use this experiment to interpret some of their rock samples.

The earth's crust consists of more than a dozen huge rafts of rock floating on a "sea" of soft rocks in the mantle beneath.
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These rafts move at about the same speed as our fingernails grow, with dramatic results! - volcanoes, mountain ranges, tsunamis and earthquakes.

Learn more **[|here]** and **[|here]** (video) ||

Do they really float? What is a subduction zone?

Easy explanations **[|here]** See a short video on volcanoes **[|here]**. || The model of the moving plates on the ocean floor, showing how volcanoes, ridges and trenches are formed. ||
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Many different minerals, including gold, are dissolved in the hot fluids in crustal rocks in volcanic zones.

As they near the surface and mix with cold sea water, they precipitate out.

They are found in large quantities near mid ocean ridges.

Imagine having to mine gold several kilometres below the ocean!

Eventually, these rocks are pushed above the surface of the sea..... then there's a gold rush!

Explore more **[|Hot rocks]** || Shelby and Tyler looking at gold. ||

Geologists can learn a great deal rocks about rocks by shining a special sort of light through a thin section. Discover how they do it **[|here]** and view some **[|Thin sections]** ||