1.a) The continental crust consists predominantly of granitic type igneous rock.
b)This rock type has a phaneritic texture (crystals are easy to see).
c) Common minerals in this rock are: quartz, feldspars, hornblende and micas. Accessory minerals are : Tourmaline, phosphates, rare earth oxides, beryl, topaz, zircons, augite, sphene, and apatite.
d)The rock is granite.
e) the composition, texture and of igneous rocks reflect the tectonic environment in which they were formed. They are found at mid - ocean ridge spreading centers. when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form igneous rocks (Grabau, 1920) .
2. a) rock type: igneous rock
b) texture: viscous liquid
c)composition: oxygen, silicon, aluminum, iron, magnesium, titanium, calcium, sodium, potassium, and phosphorus.
d) magma
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form igneous rocks (Cronies, 1936).
3. a) igneous rock
b) aphanitic texture ( crystals cannot be distinguished with the naked eye)
c) composition: silicon, aluminum, iron, magnesium, titanium, calcium, sodium, potassium, and phosphorus.
d) continental volcanic arc.
e) volcanoes are formed as a result of plate tectonic movements (Cronies, 1936).
4. a) igneous
b) composition: silicon, aluminum, iron, magnesium, titanium, calcium, sodium, potassium, and phosphorus.
c) rough, clinkery surface
d) lava
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form lava (Cronies, 1936).
5. a) rock type: igneous rock
b) composition: silicon, aluminum, iron, magnesium, titanium, calcium, sodium, potassium, and phosphorus.
c) Texture: rough, clinkery surface
d) molten lava
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form lava (Grabau, 1920).
6. a) rock type: sentimentary
b) composition: Quartz
c) Texture: crystalline
d) folded sentimentary
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form igneous rocks which disintegrate to form sedimentary rocks (Cronies, 1936).
7. a) rock type: metamorphic
b) composition: quartz, sillimanite, kyanite, staurolite, garnet.
c) texture : granular
d) rock: gneiss
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form igneous rocks which when subjected to heat and pressure change to metamorphic rocks (Cronies, 1936).
8. a) rock type: igneous
b)composition: quartz, feldspars, hornblende and micas
c)texture: phaneritic
d)rock: granite
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form granite (Cronies, 1936).
9. a) igneous rock.
b) composition: quartz, feldspars, hornblende and micas
c) texture: granular
d) granite
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form granite (Grabau, 1920).
10.a) igneous rock.
b) composition: quartz, feldspars, hornblende and micas
c) texture: granular
d) rock: granite
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form granite (Grabau, 1920).
11.a) igneous rock.
b) composition: silicon, aluminum, iron, magnesium, titanium, calcium, sodium, potassium, and phosphorus.
c) rough, clinkery surface
d) pillow lava.
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form lava (Grabau, 1920).
12.a) metamorphic
b) composition: manganese
c) texture: fine granules
d) manganese rich deposits
e) when tectonic plates rub against each other, vibrations result to the formation of weak points. Magma flows out through these weak points to form igneous rocks which when subjected to hydrothermal heat and pressure change to metamorphic rocks (Grabau, 1920).
