Travel Reference
In-Depth Information
5
Ancient
Environments
and the Level of the Sea
Sedimentary rocks continuously change in appearance as we follow them
either up or down into time. The stacked layers become more fine- or
coarse-grained, and they change from one type of sedimentary rock to an-
other. For rocks deposited beneath the sea, it seems that the depth of depo-
sition is the prime factor in dictating these changes. Water depth and
changes of water depth (which in marine environments is termed
sea level
change)
have played a large part in determining what type of sedimentary
rock is deposited in any given underwater locale—and thus have played a
major role in fashioning the appearance of our planet's sedimentary rock
cover. But sea level change has been blamed for more than simply influenc-
ing the fate of ancient sand grains (and thus complicating geologists' lives,
