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?

   • 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
   • Unit 3, because dike D cuts through it
2. 2.

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

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

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

   “(made up), bottom to top:” On card T, Luz asks which is older, the basalt sheet or Unit 3. Heat baked Unit 3 above the sheet.

   • Unit 3: the basalt baked it, so the basalt came in later
   • The basalt, because it is much harder rock than Unit 3
   • The basalt, because it lies below Unit 3 in the stack
   • Same age, because they touch along one flat line

5. 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.

6. 5.

   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 2, when Q first appeared
   • Slice 3, the only slice when both lived
   • Slice 5, when R last lived
7. 6.

   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
8. 7.

   A layer holds only fossil P. What can Pia safely say about its age?

   • It formed in slice 4, the last slice P lived
   • It formed in slice 1, when P first appeared
   • It formed sometime in slices 1 to 4; P alone cannot say which
   • Its age is unknown, since a fossil cannot narrow time whatsoever
9. 8.

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

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

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
    • Nothing is missing there, because the two rocks touch directly
    • The sandstone is older, because it sits on top of the schist
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?

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