Question

question 39
which of the following metamorphic rocks would you expect to form from a sandstone protolith?
marble
schist
hornfels
quartzite
question 40
galena and sphalerite are examples of which mineral class?
sulfides
native elements
silicates
metallic

Explanation:

• For Question 39: Sandstone, which is mainly composed of quartz grains, undergoes metamorphism to form quartzite. Marble forms from limestone, schist has a different protolith composition - often clay - rich rocks, and hornfels can form from a variety of fine - grained sedimentary rocks but not typically sandstone.
• For Question 40: Galena (PbS) and sphalerite (ZnS) are sulfide minerals as they contain metal cations bonded to sulfur anions. Native elements are single - element minerals, silicates contain silicon and oxygen, and metallic is not a standard mineral class in this context.

Answer:

Question 39: quartzite
Question 40: Sulfides