Download Kaikoura tectonic

Kaikoura
Tectonic Processes
• The Seaward Kaikoura Mountains rise to
over 2600 metres just 12km from the sea.
• The Hope fault, which marks the boundary
between the Pacific and Australian Plates,
runs along the foot of the Kaikoura
Mountains.
Kaikoura Orogeny
• This plate collision and mountain building
event began about 25 million year ago.
• In the Kaikoura region, movement
between plates changes from ocean floor
subduction to continental collision.
• As a result, blocks of land uplifted along
faults form high mountains right at the
coast, & close inshore the sea floor dives
to depths of over 1000 metres.
Photographs
What type of sediment is this?
What different sediment types can be seen in this
photograph? Describe and explain the characteristics of
each type.
Activities
• Use the Kaikoura laminated resource to
create two annotated diagrams.
• Apply your own key.
• A sketch showing the Geology of the
Peninsula.
• A cross-section diagram outlining the
geological structure.
Cross-section diagram
Cross-section diagram
• This shows the four folded formations
which make up the Kaikoura Peninsula.
• The dotted lines indicate land that has
been eroded away.
• The large scale folds are best seen on the
South Bay side of the peninsula; or at the
cliffs of Whalers Bay.
Simplified geological map
Folded limestone rocks form fascinating patterns on the shore
platforms that surround Kaikoura Peninsula. What is limestone
made of?
• Limestone rocks consist of the shells of
billions of micro-organisms, compressed
on the ocean floor between 70 & 22 million
years ago.
• Water was gradually squeezed out of the
accumulating sediments which turned from
mud to rock.
• About 15 million years ago the limestone
was buckled and twisted, before being
raised above the sea to form parts of the
present land and coastline.