Intrusive extrusive

EXTRUSIVE FEATURES

Lava Plateau
These are formed by large outpourings of fluid lava from long narrow openings in the crust (fissures).
During each eruption the lava flows out from these openings, solidifies and builds a new layer each time forming layer upon layer of solidified basalt lava.
The plateau looks flat and featureless and often has little vegetation cover
WHAT ARE THEY?

DECCAN PLATEAU
Its in India
It is 700,000km squared in area.
It was formed by 29 lava flows from a hot spot which is now under Reunion Island in the Indian Ocean.
FACTS?

Other famous plateaus? Columbia plateau in the USA and Antrim Plateau in Norther Ireland. Can you find out brief information about these too?

VOLCANOES Loads of different volcano types.
Type depends on:
Type of lava/ eruption
Type of plate boundary

SHIELD VOLCANO What are its characteristics and why? CASE STUDY MAUNA LOA - HAWAII

COMPOSITE VOLCANO What are their characteristics and why? CASE STUDIES: MOUNT ST HELENS, MONTSERRAT

INTRUSIVE FEATURES

Batholiths WHAT ARE THEY?

Sills WHAT ARE THEY?

Dykes WHAT ARE THEY?

Isle of Arran Case study

Northern Hills - Arran WHAT FEATURE?

Kidonan Shore - Arran WHAT FEATURE?

Drumadoon point - Arran WHAT FEATURE?

SEISMIC IMPACTS
FAULTING
The outer part of the earth is cold so when it is stressed it breaks easily if pushed quickly.
These breaks (caused by seismic activity) are called FAULTS.
They tend to occur on the boundaries between plates but sometimes in the middle of plates too.
Faulting occurs in the top 10 – 15km of the earth’s crust.

NORMAL FAULTS
Hanging wall moves down leaving a very steep fault plane. Usually caused by the plates moving apart (divergent)
The result of this fault movement is a cliff like feature called a fault scarp. A number of these were found in the Sichuan province in China after the earthquake there.

REVERSE FAULTS
These occur when the hanging wall moves upwards. The forces here are compressional (convergent boundaries)
A number of these were found in the Sichuan province in China after the earthquake there.

Sichuan Province quake
12 th May 2008
Collision boundary (Indo Australian and Eurasion)
7.9 Richter scale.
60,000 plus deaths

The San Andreas Fault

RIFT VALLEYS - East Africa

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Intrusive extrusive

by jodiecmills on Jan 17, 2011

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Intrusive extrusive — Presentation Transcript