Assessment 1.5

A mineral can be

• Complex structure with distinct properties that builds a rock

• Organic, crystalline, and generally softer than a rock

• Synthetic, crystalline, and cannot be made in a laboratory
  

• Naturally occurring, inorganic, solid, with a fixed chemical formula

Which property is most reliable for distinguishing look-alike opaque minerals?

• Color

• Luster

• Streak

• Specific gravity

Only minerals softer than the streak plate will leave a true streak. The streak plate hardness is about:

• 7.5

• 6

• 6.5

• 7

A student finds that their sample scratches orthoclase but is scratched by quartz. The hardness is:

• 5–6

• 6–7

• 7–8

• 4–5

Extrusive igneous rocks cool quickly and are typically:

• Coarse-grained

• Foliated

• Fine-grained/glassy/vesicular

• Non-crystalline only

Conglomerate vs. breccia differ mainly by:

• Mineralogy

• Grain roundness (rounded vs. angular clasts)

• Cement type

• Bedding thickness

Banding/planar alignment is most diagnostic of which group?

• Crystalline

• Metamorphic

• Bioclastics

• Gneiss

Most petroleum reservoirs are found in sedimentary basins primarily because:

• Igneous rocks have higher porosity

• Sedimentary processes create porous-permeable rocks and stratigraphic/structural traps

• Metamorphism increases primary porosity

• Only basalts can trap hydrocarbons

At a subduction zone, you expect:

• Plates diverging and new crust forming

• Plates sliding past each other

• One plate sinking beneath another (oceanic under continental or oceanic)

• No seismicity

In the E&P lifecycle, adding compression to maintain flow as reservoir pressure declines belongs to:

• Exploration

• Development

• Production

• Abandonment