Earth Science Rock Garden
We made a rock garden at the side of the Building no. 14 in Oct. 28, 2001. Rocks in this garden are composed of several kind of rocks which construct the earth's crust. These rocks are titled "A letter from an abyss", "A letter from the deeper part of a continental crust", and "A letter from a mantle", respectively.
Minamigumi Co., Ltd., Samani Town, Hokkaido, donated these rocks. We appreciate their donation.
"A letter from an abyss" |
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These rocks are called chert which is composed of fossils of radioralia, a kind of plankton. Several million years ago, radioralian tests deposited at abyssal plane, and had been moved over a few thousand km associated with the drifting of an oceanic plate. |
" A letter from the deeper part of a continental crust" |
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The deeper we go down, the higher pressure and temperature become. About in 20 km depth, rocks change their properties or partly molten into the source of magma. The magma produced in this way frequently shows complicated structures mixing with surrounding rocks. |
"A letter from a mantle" |
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The mantle underneath the crust constructs volume of 80% of the earth. The movement of mantle is significant as the cause of plate tectonics and plume tectonics, as well as the site of magma generation. |