Fold-mountain building, ridges, volcanic arcs Flashcards
Orogenic mountain belts are…
linear or arcuate chains, associated with convergent plate margins, formed on land.
Where an ocean plate meets continental…
the lighter, less dense continental plate may be folded into folded mountains e.g. Andes.
Where two continental plates converge…
both plates may be folded e.g. the Himalayas, formed by Eurasian and Indian plates
Crustal thickening results in…
the uplift of the Himalayas. It refers to process when one continental crust is forced to another.
Ocean ridges are…
giant submarine mountain chains with a length of more than 60 000km.
At mid-ocean ridges, the new…
lithosphere is created.
Ridges can also occur at…
the margins of oceans, e.g. the East Pacific Rise.
Ridges at the margins of ocean form behind…
the volcanic arcs of subduction zones.
The volcanic arc is formed when…
oceanic lithosphere is subducted beneath the oceanic lithosphere.
(Ocean-ocean subduction zone) There is a trench outer rise which is…
a low bulge on the seafloor ahead of the subduction zone, caused by the bending of the plate as it is subducted.
(Ocean-ocean subduction zone) The outer slope of…
the trench is found on the subducted plate and it’s generally gentle, broken by faults as the plate bends. The floor of the trench is covered with turbidites and ash.
(Ocean-ocean subduction zone) The trench inner slope…
is steeper and contains fragments of the subducting plate.
(Ocean-ocean subduction zone) The subduction complex is…
the slice of the descending slab and may form significant landforms e.g. island Barbados is the top of the subduction complex.
(Ocean-ocean subduction zone) Most subduction zones contain…
an island arcs, located parallel to a trench on the overriding plate. Found 150-200km from the trench. E.g. Grenada
