Question

sedimentation, fossilization review assignment page
name kenneth date per 154

1. sedimentation and the fossil record

which type of sedimentary environment is most likely to preserve fossils well?
a) mountain peaks with rapid erosion
b) deep ocean trenches with little sediment accumulation
c) calm lake beds with fine sediment deposits
d) desert sand dunes with frequent wind shifts

1. fossilization and the fossil record

what is the most common process by which fossils are formed?
a) freezing of organisms in ice
b) replacement of organic material with minerals
c) preservation in amber
d) desiccation (drying out)

1. unconformities and the fossil record

an unconformity in the geologic record represents:
a) a continuous sequence of sedimentary layers
b) a gap in the rock record due to erosion or non-deposition
c) the sudden appearance of many new fossil species
d) a volcanic eruption layer that preserves fossils

1. bias in the fossil record

which factor contributes most to bias in the fossil record?
a) equal preservation of all organisms regardless of habitat
b) rapid burial and hard body parts increase fossil preservation
c) fossils always form in the same rock types
d) fossils are equally likely to be found everywhere on earth

Explanation:

1. Calm lake beds with fine sediment deposits (Option C) are good for fossil preservation as the fine sediments can quickly cover organisms, protecting them from decay and damage. Mountain peaks with erosion (A) would erode fossils, deep ocean trenches with little sediment (B) lack material to cover fossils well, and desert sand dunes (D) have unstable conditions.
2. The most common fossil - forming process is the replacement of organic material with minerals (Option B). Freezing (A), preservation in amber (C), and desiccation (D) are less common compared to mineral replacement.
3. An unconformity in the geologic record is a gap due to erosion or non - deposition (Option B). A continuous sequence (A) is not an unconformity, sudden appearance of new species (C) is related to evolution events, and a volcanic layer (D) is not an unconformity.
4. Rapid burial and hard body parts increase fossil preservation (Option B). Equal preservation (A) is not true as different organisms have different preservation potentials. Fossils do not always form in the same rock types (C), and they are not equally likely to be found everywhere (D) due to differences in preservation environments.

Answer:

1. C. Calm lake beds with fine sediment deposits
2. B. Replacement of organic material with minerals
3. B. A gap in the rock record due to erosion or non - deposition
4. B. Rapid burial and hard body parts increase fossil preservation