geologic features (trench, atoll, rift valley and lake)

GEOLOGICFEATURES

BY: SARAH JANE B. JARINA

TRENCHIt is a deep and narrow

hole or ditch in the ground.

TRENCH IN A CONVERGENT ZONE

TWO WAYS WHERE TRENCH WAS FORMED1. OCEANIC-OCEANIC PLATES CONVERGE

2. OCEANIC-CONTINENTAL PLATES CONVERGE

1. OCEANIC-OCEANIC PLATES CONVERGE

Volcanic Island Arcs They result from the subduction of an oceanic tectonic plate under another tectonic plate, and often parallel an oceanic trench.

VOLCANIC ISLAND ARC - a solitary mountain formed by volcanic activity. Lava erupting from the sea floor builds up on the sea bed over thousands, or even millions of years.

2. OCEANIC-CONTINENTAL PLATES CONVERGE

Volcanic Arc-It is a chain of volcanoes formed above a subducting plate, positioned in an arc shape.-it was formed when two oceanic plates converge.

RIFT VALLEYIt is a linear-shaped lowland

between several highlands or mountain ranges.

How valley was formed?

It is formed in a divergent plate boundary.

As the crust pulled apart, large slabs of rock sink, generating a rift zone.

Rift valleys

ATOLL

• It is a ring-shaped coral reef, island, or series of islets.

• Develop with underwater volcanoes called seamount.

ATOLL

How atoll was formed?

It was developed in underwater volcanoes.

Lady Musgrave Island Coral Atoll in Australia

Hermatypic corals/ Hard corals Corals that buid a reef below the ocean surface.

Fringing Reef A reef that was built by corals.

Great Blue Holeto

Lagoon An area of sea water that is separated from the ocean by a reef or sandbar.

•All lakes fill bowl-shaped depressions in the Earth's surface, called basins.•A lake is a body of water that is surrounded by land.

LAKE

How lake was formed?

Ice

water

How lake was formed?

Many lakes, were formed by glaciers that covered large areas of land during the most recent ice age, about 18,000 years ago.

GLACIAL LAKE

How lake was formed?CRATER LAKE

After a volcano becomes inactive, its crater may fill with rain or melted snow.

How lake was formed?

BY THE PLATE TECTONIC

Some lake basins form where plate tectonics changed the Earth’s crust, making it buckle and fold or break apart.