Mountain Building

Question 1

Island arc

Answer 1

Two oceanic plates converge and one is subsucted beneath the other
Typically found on margins of an ocean basin
Partial melting of mantle wedge located above sunducting plate and leads to growth of volcanic island arc

Question 2

Continental volcanic arc

Answer 2

Subduction beneath a continental block results in formation of continental volcanic arc along the margin of the adjacent landmass

Question 3

Passive continental margin

Answer 3

Not a plate boundary but a part of the same plate as the adjoining oceanic crust. Steadily subsiding and accumulating sediment

Question 4

Active continental margins

Answer 4

Consists of trench and subduction zones

Question 5

Accretionary wedge

Answer 5

Chaotic accumulation of sedimentary and metamorphic rocks with occasional scraps of ocean crust derived from land and scraped from the subducting plate during the development of a continental volcanic arc

Question 6

Terrane

Answer 6

Accreted crustal blocks resulting from collision of comparatively small crustal fragments to a continental margin
Any crystal fragment that has a geologic history distinct from that of adjoining terranes

Question 7

Fault-block mountains

Answer 7

Mountains formed by tectonic processes such as continental rifting that produce uplift and the formation of topographic mountains that are bounded by high-angle normal faults that gradually flatten with depth

Question 8

Isostacy

Answer 8

The concept of a floating crust in gravitational balance

Question 9

Isostatic adjustment

Answer 9

Establishing a new level of gravitational equilibrium

Question 10

Orogenesis

Answer 10

The processes that collectively produce a mountain belt