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大地のなりたち
地学の「展示室」
変化が穏やかである大陸地域と比べ、ニュージーランド南島は、地学の「展示室」として国際的に注目されるほど、地殻変動（ちかくへんどう）が活発で、さまざまな岩石の種類が存在する地域として知られています。地中深くで、絶え間なく衝突する地殻の動きに呼応するため、ここでは岩石はまるで「生物」のように、常に動き、姿を変えています。
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オタゴ周辺（ニュージーランド南島南部）の地形
Maps courtesy of Institute of Geological & Nuclear Sciences
南島の多様な地質をあらわした地質図には、地質を示す色彩があざやかな図形を描きだしています。
■地図中央に大きな弧（こ）を描く片岩（へんがん）―オタゴの基盤となる岩質。
■片岩の帯の横に位置する硬砂岩とセミ・シスト（片岩の一種）。がれ場の多い北オタゴ、カンタベリー山脈など北部ではより特徴的。
■北オタゴ、ワイタキ峡谷などで目立つ石灰岩や海緑石砂岩をはじめとする堆積（たいせき）岩。
■マニオトト平原とともに、ダニーデン周辺で見られるような火山岩。
■「ムリヒク・テレーン」とよばれる、ラフな三角形で表現される、南オタゴの砂岩や変成岩。
■フィヨルドランドの花崗（かこう）岩などの火成岩。これは4億5千年〜5億年前に生成されたニュージーランド南島で最古の岩石。
The Lie Of the Land
A Geological 'Event Centre'
Southern New Zealand exhibits a remarkable array of landforms, geological processes and rock types.
Compared to continental regions of the world, where change is often slow, Southern New Zealand is a dynamic place geologically - a geological 'event centre' attracting international interest. Here, the rocks are and but alive. They move. They change. They respond to colliding forces in the earth that are deep-seated and persistent.
Prominent elements in the landscape:
*A crease down the western side, reaching the sea at Milford Sound - the crunch zone of two colliding plates of the earth's crust.
*A mountain chain thrust up on the western side - the Southern Alps.
*Fiords carved by glaciers in the southwest corner.
*Large glacial lakes to the east of the high mountains.
*Parallel ranges, with intervening valleys, lying like a crumpled mat across Central Otago.
南オタゴの岩礁「ナジェッツ」
*An inland basin (Mackenzie Basin) north of Central Otago, featuring braided river systems.
*The great rivers of the Clutha and Waitaki, rising in the western mountains and discharging on the east coast.
*Southland's broad plains, formed from outwash gravels after the ice-age glaciers retreated.
*Parallel ridges inland of the Catlins coast south of the Clutha River, marking the Southland Syncline.
A geological map of Southern New Zealand displays swathes and splashes of colour reflecting the region's varied geology:
*Schist sweeps through the centre of the map -the mainstay rock type of Otago.
*Greywacke and semi-schist flank Otago's motherlode of schist, with semi-schist more prominent to the north, in - the scree-prone North Otago and Canterbury mountains.
*Sedimentary rocks, including limestone and greensand, stand out in North Otago, Waitaki Valley and South Canterbury.
*Volcanic rocks dominate in the Dunedin area, with outliers as far east as the Maniototo Plains.
*Sandstone and metamorphic rocks south of Otago, in a roughly triangular wedge called the Murihiku Terrane. Here, the Southland Syncline shows up as a series of parallel ranges.
*Granite and other igneous rocks in Fiordland, where there are also ancient slates, the oldest rocks in Southern New Zealand at 450 to 500 million years of age.
マウントクック（アオラキ山）とサザンアルプス
ダウトゥフルサウンド（フィヨルドランド）
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