Put rock layers in order

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   On card K, Ari compares Unit 3 with dike D. Which is older, and why?

   • Unit 3, because dike D cuts through it
   • Dike D, because it is basalt and Unit 3 is limestone
   • Dike D, because it reaches deeper than Unit 3 does
   • Neither; one cannot be older without a date
2. 2.

   On card H, Bo asks which came first, the tilting of Units A to C or the laying down of flat Unit D?

   • Units A to C were tilted after D had covered them
   • Unit D came first, then everything was tilted after it
   • Tilting came first; D was laid on the eroded edges
   • They happened together, as Unit D slowly formed
3. 3.

   On card G, Esme wants the oldest rock. Granite B holds chunks of Unit 1. Which is oldest?

   • Unit 3: it holds pebbles of the granite itself
   • Granite B: it cuts through the lowest units of the cliff
   • Unit 4: it is the top layer of the whole cliff
   • Unit 1: bottom layer, with chunks inside the granite
4. 4.

   On card S, Jun decides whether the basalt sheet is older or younger than Unit 3. Which answer fits the evidence?

   • Younger: Unit 3 holds basalt pebbles, so Unit 3 came first
   • Neither can be known without a radiometric date
   • Younger: it baked Unit 2, so it flowed in after Unit 3
   • Older: Unit 3 holds basalt pebbles, so basalt came first
5. 5.

   Fault F on card K offsets dike D and Unit 4. What does Kira learn about Unit 4 and the fault?

   • Both formed at the same moment
   • Unit 4 came first, and fault F broke it later
   • Unit 4 is the youngest event, since it is the top layer
   • Fault F came first, and Unit 4 was laid over it

6. Read this first

   Table, Fossil ranges (made up), with columns Fossil, Time slices lived (1 oldest, 6 youngest), Where found

   P, 1 to 4, worldwide; Q, 2 to 3, one basin only; R, 3 to 5, worldwide; S, 5, worldwide. Note: A time slice is one equal span of time.

7. 6.

   A layer holds fossils Q and R. In which time slice did Milo's layer form?

   • Slices 2 to 5, every slice either one lived
   • Slice 3, the only slice when both lived
   • Slice 2, when Q first appeared
   • Slice 5, when R last lived
8. 7.

   Noah needs one fossil to match rocks on different continents. Which is the best index fossil?

   • P: it lived the longest, so it fits the most rock
   • R: it is worldwide, though it lived three slices
   • S: it lived for one slice and is found worldwide
   • Q: it lived a short time, though in one basin alone
9. 8.

   On card H, Ren studies the wavy surface between Unit C and flat Unit D. What does it show?

   • Time is missing: tilted layers eroded before D formed
   • D is older, because it stayed flat and undisturbed
   • Nothing is missing; C simply ends and D starts
   • The layers were laid down in one single event

10. NPS (Grand Canyon)

    The Layered Paleozoic Rocks are about 510 Ma; the Vishnu Basement Rocks are about 1.75 billion years (1,750 Ma). At the Great Unconformity they touch directly.

11. 9.

    At one Grand Canyon spot, 510 million-year-old (510 Ma) sandstone rests on 1.75 billion-year-old schist. What does Tala infer?

    • About 1.2 billion years of rock record are missing there
    • About 510 million years are missing from the record there
    • The sandstone is older, because it sits on top of the schist
    • Nothing is missing there, because the two rocks touch directly
12. 10.

    Zee sees flat layers, but the boundary between two of them is rough and cuts into the lower layer. What does it mean?

    • Erosion cut the lower layer before the upper layer was laid down
    • Both layers formed at the same moment
    • The upper layer is older, since it is pressed into the lower
    • It is a normal boundary, so no time is missing