Question

46. The dashed line that separates crust from uppermost manitleis Due on Wed, 8 May 19 a. ecotone b. lithopause c. Mohorovicic discontinuity ("Moho d. lithification zone mantle is known as the: described as a: a. Convergent plate boundary b. Divergent plate boundary C. Transform plate boundary d. Hot spot (no plate boundary). 48. This silicate mineral cleaves into thin sheets Quartz (SiO2) a. b. Potassium feldspar (KAISaOs). C. Olivine ((Fe, Mg)2SiO4). d. Muscovite mica (KAlbSisO10(OH, F)h). e. None of the above. 49. This silicate mineral is very common and is a 7" out of 10 on the Moh's Mineral Hardness Scale: a. Quartz (SiO2) b. Potassium feldspar (KAISisOs). c. Olivine ((Fe, Mg)2SiO4). d. Muscovite mica (KAlsSigOto(OH, F)2). e. None of the above. 50. This carbonate mineral is a "3" out of 10 on the Moh's Mineral Hardness Scale: a. Galena (PbS) b. Pyrite (FeS2) c. Calcite (CaCOs) d. Diamond (C) e. Quartz (Si02) This native element mineral is a "10" out of 10 on the Moh's Mineral Hardness Scale: a. Halite (NaCl) b. Diamond (C) C. Gold (Au) d. Potassium feldspar (KAISig0e) e. Olivine (Fe, Mg)2Sio) 51. The sulfide minera in this image is also known as "fool's gold" (FeSa): a. Galena b. Pyrite c. Olivine d. Gypsum e. Obsidian 52. n wnrth 7Q oints and due in class on Wed, 8 May '19. Page 7 of 10

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Answer 1

Ans. 46. The dashed line that separates crust from uppermost mantle is (c) the Mohorovicic discontinuity ("Moho"). It is the discontinuity that marks the end of crustal part and inception of the mantle region. It usually lies at a depth of about 40 - 50 km below the continental crust and 10 - 12 km below the surface of the earth in case of oceans. At this line, there is a sharp increase in seismic wave velocity.

Ans. 47. The San Andreas fault located in California is (c) transform fault. In transform fault, the tectonic plates in unison slide past each other. The San Andreas fault is formed between the North American Plate and the Pacific Plate.

Ans. 48. The silicate mineral cleaves into thin sheets is (d) muscovite mica. In muscovite mica the presence of basal cleavage leads to the cleaving of thin sheets of the mineral.

Ans. 49. The silicate mineral is very common and is a 7 out of 10 on the Moh's mineral hardness scale hardness is (a) Quartz (SiO₂). The Moh's scale is based on the property of leaving scratch on the the mineral with lower values in the hardness scale. There are 10 minerals in the scale and is given below in sequence:

1. Talc

2. Gypsum

3. Calcite

4. Fluortie

5. Apatitie

6. Feldspar

7. Quartz

8. Topaz

9. Corundum

10. Diamond

Ans. 50. This carbonate mineral is 3 out of 10 on the Moh's mineral hardness scale. It is (c) calcite (CaCO₃). So, it is able to scratch both talc and gypsum.

Ans. 51. The native element mineral is a 10 out of 10 on the Moh's mineral hardness scale is (b) diamond. So, it is the hardest mineral.

Ans. 52. The sulfide in the image (not given) is also called fool's gold (FeS₂). It is (b) pyrite. The luster of pyrites along with its yellowish hue makes it look like gold and thus is known as the fool's gold.