QUESTIONS
1- The solid Earth is subdivided chemically into three layers; Outer……(1)……., Middle……(2)…….. and inner ……(3)…….., while it physically contains 5 layers including …(1)………in the center, and overlain outward by …(2)…………, ……(3)……..,……(4)……… and ……(5)………
2- Continental crust is ………a) Silaic b)Simatic…. crust, made up mainly of ……… a) igneous ……………b) metamorphic ………c) sedimentary ………d) all… with chemical composition is similar to ………..a)granite…….b) Gabbro…….c) limestone, and enriched in ……….a)heavy elements such as Fe, Mg ……. b)light minerals such as Al & Si…
3- Marianas Islands was formed by………………… and Himalayan mountain range is a result of two……..
a) continental plate convergence a) continental plate divergence
c) oceanic plate convergence d) oceanic plate divergence
e) convergence of two oceanic plates f) divergence of two oceanic plates g) convergence of oceanic and continental plates
4- San Andreas Fault is a product of ……….
a) Plate convergence b) Plate divergence c) Transform boundaries
5- The rocks at the mantle are denser than those of crust. (X) OR (√)
6- The age of the oceanic crust becomes progressively younger in both directions away from the ridge a) X b) √
7- Divergent boundaries are of constructive type. Explain
8- Are there any relationship between the thickness of marine sediments and the age of oceanic crust?
9- Oceanic crust is younger than continental crust Explain?
__________
ANSWERS
1- Crust, mantle, core, inner core, outer core, mesosphere, asthenosphere and lithosphere.
2- a) Silaic d) all, .a) granite, b) light minerals such as Al & Si.
3- Oceanic plate convergence, continental plate convergence
4- Transform boundaries
5- (√)
6- X
7- Because of adding and building new oceanic crust through spreading center
8- The oldest oceanic crust that occurs distant from the spreading center covered by thicker sediments, while the younger ones near the ridge is covered with thin sediment.
9- Oceanic crust is no older than 200 million years, whereas continental crust is assigned back to 3.5 billion years and new continental crust is continuously added at the spreading center