Page 211 - Laboratory Manual in Physical Geology

A CTIVIT Y 6.10 “Reading” Earth History from a Sequence of Strata

Name: ______________________________________ Course/Section: ______________________ Date: ___________

A. Permian strata (about 270 million years old) exposed along Interstate Route 70 in northeastern Kansas. Describe the
paleoenvironment (pink column), then apply it to infer the record of change (purple column).
RECORD OF
DESCRIPTION OF
HAND SAMPLE CHANGE
OUTCROP Bedding plane DESCRIPTION OF PALEOENVIRONMENT
ROCK UNIT
REPRESENTED BY
surface
THE ROCK UNIT
ocean (marine) muddy bay/estuary evaporating bay peat bog or swamp

7. Tan skeletal limestone land
with shells of many kinds
of marine organisms,
bimodal cross-bedding,
oscillation ripple marks,
animal burrows, flutes,
flute casts, and chert.

6. Gray silty mudstone
(shale) with animal
burrows, fossil
clams, fossil plant
fragments, and current
ripple marks.

5. Red and gray silty
mudstone with
raindrop impressions,
fossil roots, and
mudcracks.

4. Gray silty mudstone
with abundant gypsum
layers and crystals.

3. Tan skeletal limestone
with bimodal
cross-bedding.
2. Coal. peat bog or swamp

Probably moist muddy
1. Gray silty mudstone land where ferns grew;
with mudcracks and mudcracks formed in
fossil ferns.
dry periods.
1 METER

B. REFLECT & DISCUSS What could have caused the sea level to rise and fall in this way about 270 million years ago?

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