Read topographic and geologic maps

Grade 9 Science Worksheet

Circle the best answer.

1. 1.

   Contour interval 20 feet. The outermost closed contour of a hill is 400 feet; the innermost is 640 feet. Ari counts closed contours on a hill. The outermost is 400 ft, the innermost is 640 ft, and the interval is 20 ft. How many lines is that?

   • 12 lines, found as (640 − 400) ÷ 20
   • 13 lines, since (640 − 400) ÷ 20 is 12, plus 1
   • 14 lines, found by adding a line at each end
   • 240 lines, found as 640 − 400

2. Read this first

   Elevation along line A to A′ (made up)

   Distance from A (miles)	Elevation (feet)
   0	1,200
   0.5	1,280
   1.0	1,520
   2.0	1,820
   2.5	1,600
   3.0	1,400

3. 2.

   Bo reads the elevation profile along A to A′. What is the relief along the line, from lowest to highest point?

   • 200 ft, found as the end (1,400) minus the start
   • 1,820 ft, the highest elevation on the line
   • 620 ft, found as 1,820 − 1,200
   • 300 ft, the biggest single rise between points

4. Card

   a stream drops from 1,000 feet to 960 feet over 3 inches on a 1:24,000 map. 1 inch is 2,000 feet and 1 mile is 5,280 feet.

5. 3.

   A stream crosses the 1,000 ft line, then the 960 ft line 3 inches away on a 1:24,000 map. What gradient does Esme find, in feet per mile?

   • About 0.007 ft per mile, found without 5,280
   • About 35 ft per mile, from 40 ÷ 6,000 × 5,280
   • About 13 ft per mile, found as 40 ÷ 3
   • About 3 ft per mile, found by using 1 inch = 24,000 ft

6. Elevation along line A to A′ (made up)

   Distance from A (miles)	Elevation (feet)
   0	1,200
   0.5	1,280
   1.0	1,520
   2.0	1,820
   2.5	1,600
   3.0	1,400

7. 4.

   Using the profile along A to A′, Jun looks for the steepest segment. Which one is it, in feet per mile?

   • 0 to 0.5 mi, the first segment, at 160 ft per mile
   • 2.0 to 2.5 mi, the biggest drop, 220 ft
   • 0.5 to 1.0 mi, at 480 ft per mile
   • 1.0 to 2.0 mi, the biggest rise, 300 ft
8. 5.

   Near point P the 1,000 foot contour bends into a V that points northeast. Elevations rise toward the northeast. Near point P, the 1,000 ft contour bends into a V pointing northeast, and heights rise to the northeast. Which way does Milo's stream flow?

   • Northwest, along the 1,000 ft contour
   • Southeast, as that is the way V's point on a ridge
   • Southwest, away from the V's point
   • Northeast, toward the V's point

9. Card

   1:24,000 map, 1 inch = 2,000 feet. Stream M drops 60 feet over 1.5 inches. Stream N drops 40 feet over 0.5 inch.

10. 6.

    Stream M drops 60 ft over 1.5 inches. Stream N drops 40 ft over 0.5 inch. Both are on a 1:24,000 map. Which is steeper, by Noah's slopes?

    • The same, since the scale is the same for both
    • Stream M, since it drops more feet, 60 against 40
    • Stream N: 40 ÷ 1,000 is 0.04, double M's 0.02
    • Stream M, since it is longer on the map

11. Card (USGS)

    Valleys cut by streams make V's in contour lines; glacial valleys make U's. Contours here form a U with a wide, flat bottom.

12. 7.

    Pia's contours run around a valley in a U shape with a wide, flat bottom. What does that suggest?

    • A ridge, since U shapes point downhill along the slope
    • A stream cut it, since V shapes are the mark of glaciers
    • A glacier may have carved it; glacial valleys make U's
    • A hilltop, since closed contours form U shapes on maps

13. Use this

    Geologic map G (made up). Legend, youngest to oldest: Qal, alluvium (Quaternary, yellow); Ks, sandstone (Cretaceous, olive); Jm, mudstone (Jurassic, green); Pl, limestone (Permian, blue); Xg, gneiss (Precambrian, gray). Xg lies in the southwest. Pl lies north of Xg and rests on it. Jm lies north of Pl, and Ks lies north of Jm. Dike d (diabase) cuts Xg and Pl and ends at the Jm contact. Alluvium Qal fills the stream valley and covers the edge of Ks. Fault f cuts Pl, Jm and Ks but not Qal.

14. 8.

    On map G, fault f cuts Pl, Jm and Ks but not Qal. Ren dates the fault. When did it move?

    • Before Pl (Permian), since it cuts the oldest units
    • After Ks (Cretaceous) and before Qal (Quaternary)
    • After Qal (Quaternary), since faults cut any unit
    • Before Ks (Cretaceous), since Ks lies north of the fault
15. 9.

    On map G, what age range can Tala give for dike d?

    • Younger than Ks (Cretaceous), since dikes are the newest
    • Younger than Pl (Permian) and older than Jm (Jurassic)
    • The same age as Pl (Permian), since it cuts through Pl
    • Older than Xg (Precambrian), since it cuts Xg
16. 10.

    On map G, Jm (Jurassic) lies directly on Pl (Permian). What does Zee infer about the Triassic?

    • The Triassic is the same age as Jm, so it is mapped as Jm
    • No Triassic rock is shown there, so a gap in the record is likely
    • The Triassic is older than Pl, so it is part of the Xg gneiss
    • Triassic rock is hidden under Jm, so nothing is missing there