Question

11. Fill in the blanks on the attached image of the "Ridee to Trench" tectonic system. (20 pts, fotol) SZ Jue] What type of crust (2 pts.) Thickness of a (km): (2 pts.) (2 pts.) (2 pts.) Thickness of b (km): (2 pts.) Density of c (g/cm'); (2 pts.) (2 pt.) (2 pt.) (2 pt.) (2 p.) 12. Fill out the following Time Plot Chart for the attached Time Series (10 pts. total) A. GPS Station Name: _(1 pts.) B. Latitude Vector direction (North or South) and velocity: (1 pts.) C. Longitude Vector direction (East or West) and velocity (1 pts.)

Answer 1

a) Oceanic crust. Thickness of a varies from 5-10 km.

b) Continental crust. Thickness of b varies from 30-50 km.

Density of oceanic crust (3 g/cm³) is greater than continental crust ( 2.7 g/cm³). This is the reason oceanic crust always goes under continental crust during a collision tectonic event.

c) Upper part of mantle. Density of c is 3.4 g/cm³.

On the basis of mineral composition and change in seismic velocity Earth's mantle is divided into two layers, upper mantle ( Peridotite, Eclogite, Garnet, Spinel, olivine, Pyroxene) and lower mantle (Magnesium and Silicon oxides). In between the two layers one transitional layer can be found with mineral Perovskite. Lower mantle has density of 5.6 g/cm³.

d) Mid oceanic Ridge.

Under-ocean mountain chain formed by uplifting of oceanic crust in a diverging manner. This is a result of rising convection current of mantle magma.

e) Accretionary Wedge.

Formed by the scraped off sediments of a subducting oceanic plate which are accumulated at the edge of continental crust in a thrusting manner.

f) Fore-arc region.

The area between the subduction zone and connected volcanic chain.

g) Volcanic-arc.

Long chain of volcanoes formed along a subduction zone .