Jhonson classification of shorlines

By ANISH KUMAR S
MSC GEOLOGY
CENTRAL UNIVERSITY OF TAMIL NADU

1. D.W. Johnson's Classification of shorelines

2. What are Shorelines? What is the difference between coastlines and shorelines?

3. D.W. Johnson (1919) presented a genetic classification of shoreline. He divided shorelines into 4 main types on the basis of Nature of coastland before changes in sea level. Emergence or submergence of shorelines due to sea level change Johnson’s Classification O f Shorelines

4. Shoreline of Emergence Formed due to fall in sea level/Negative change The negative change may be due to either Climatic factor (ice age and widespread glaciation) or Tectonic factor (Subsidence in seafloor or rise in coastland) A straight/Gently curving shoreline dominates in this type

5. Formed due to the submergence of coastal land due to rise in sea level. Positive change may be due to the interglacial period leading to deglaciation or due to any tectonic movement(Subsidence of seafloor or coastal area). Shoreline of Submergence

6. No evidence to reveal submergence or emergence. In fact Neutral shorelines are formed due to deposition of sediments. Johnson identifies six types of shoreline under this category Delta shoreline Alluvial plain shoreline Outwash plain shoreline Volcanic shoreline Coral reef shoreline Fault shoreline Neutral Shorelines

7. Characterized by evidence of both submergence and emergence. Compound Shoreline Norwegian Coast