Modul 4 - Dinamika Bumi
Modul 4 - Dinamika Bumi
Modul 4 - Dinamika Bumi
TINGGIAN
What is weather?
What is climate?
How do they differ?
• Shorelines
• Deserts
• Groundwater
http://www.berann.com
What drives plate motions
• Forces that drive plate
motion
– Slab-pull
• Cold, dense slabs of
subducted oceanic
lithosphere pull the plate
towards the subduction zone
– Ridge-push
• The higher elevation of
spreading centers result in
oceanic lithosphere wanting
to move “downhill”, away
from the ridge
• Far less important than
slab-pull
– Mantle drag and plate
resistance
• Can act to increase or
decrease plate motion
Mantle convection provides
the primary drive for
plate tectonics
What drives plate motions
• Models of plate-mantle
convection
• Any model must be consistent
with observed physical and
chemical properties of the
mantle
• Horizontal movement of plates
causes mantle upwelling
• Models
– Layering at 660 km
– Explains why basalts
erupted at mid-ocean
ridges are different (more
evolved, relatively shallow
source) compared to those
erupted at hot-spots (more
primitive, deeper source).
– We know that subducting
slabs descend beneath 660
km
What drives plate motions
• Whole-mantle convection
– Would mix the entire
mantle in the space of a
few hundred million
years, removing
heterogeneities
What drives plate motions
• Deep-layer model
– “Lava lamp model”
– Two layers swell and
shrink in a complex
fashion in response to
heat from the Earth’s
interior
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