Laboratory Manual for Introductory Geology 4e

17.2.5 Emergent and Submergent Shorelines
Short-term fluctuations in sea level occur sporadically during major storms and
twice daily with the tidal cycle, but long-term sea-level changes are caused by tectonic
activity and climate change. Geologists commonly group shorelines into two
categories based on how they respond to these long-term changes:
1. Along submergent shorelines, the land sinks or sea level rises. The shoreline
appears to be drowned, with an irregular coastline, prominent bays, and abundant
islands, marshes, and lagoons.
2. Along emergent shorelines, the land rises or sea level drops. Emergent shorelines
are typically straight and bounded by steep cliffs; where tectonic uplift
has occurred, remnants of former shoreline features may be found well above
sea level.
The following exercises will give you some practice in recognizing different
types of shorelines, the processes that create them, and the ways in which they have
changed over time.
EXERCISE 17.2
Effects of Climate Change on Shorelines
Name:
Course:
Section:
Date:
(a) What would be the effect on the world’s oceans if continental glaciers worldwide expanded by 10%? Explain.
(b) What would be the effect on the world’s shorelines if continental glaciers worldwide expanded by 10%?
(c) Conversely, what would be the effect on the world’s oceans and shorelines if continental glaciers shrunk by 10%?
(d) Starting about 2 million years ago, much of northern North America, Europe, and Asia were covered with
continental glaciers. In what way was the location of the world’s shorelines at that time different from that of
today’s shorelines? Explain your reasoning.
17.2 FACTORS CONTROLLING SHORELINE FORMATION AND EVOLUTION
437