Author Question: When geologists trace a layer of sediment or sedimentary rock laterally, the layers change in ... (Read 180 times)

JMatthes · **on:** Jul 13, 2018

When geologists trace a layer of sediment or sedimentary rock laterally, the layers change in composition, texture, or both. These changes result from the ____.
A)metamorphosis of the constituent rocks
B)tilting of the parent rock during formation
C)abrupt disturbances of the depositional environment
D)different rates of weathering in different layers of rock
E)simultaneous operation of different processes in adjacent depositional environments

Question 2

What is the age of the Burgess Shale? What is its significance, and why did this unique preservation occur?

jgranad15 · **Reply #1 on:** Jul 13, 2018

Answer to Question 1

E

Answer to Question 2

The Burgess Shale dates from the Middle Cambrian. The animals and enclosing mud were transported by slumps to anaerobic conditions where bacterial activity could not destroy the buried animals. This allowed preservation of this unique assemblage of fossils of soft-bodied animals.