1 Introduction 



Background 



Coastal environments display great geologic and geomorphic 1 diversity 

 over space and time. Spatial diversity occurs because coastal landforms 

 develop in a variety of terrestrial and marine environments from a variety of 

 rocks and sediments. Environmental factors, such as coastal winds, waves, 

 tides, currents, storms, sea level, tectonics, sediment supply, and human 

 influences, cause vast geographic variation. Temporal diversity in landforms 

 and materials occurs largely because environmental factors fluctuate over 

 time. These environmental variations may be cyclic, noncyclic, or 

 unidirectional over the time period examined. As a result, the geologic and 

 geomorphic history of a coastal area is a response to a multiplicity of 

 environmental factors over a variety of time scales. 



The assimilation of evidence and the interpretation of geologic and 

 geomorphic history of a coastal area require an understanding of the system's 

 dynamics and its response to temporal and spatial environmental changes. 

 Each facet of the coastal system is constantly changing and each altered facet 

 influences subsequent changes to the system. Data which indicate the rates, 

 magnitude, and frequency of phenomena such as the effects of storms, sea 

 level rise, coastal erosion, or the subsidence of continental margins, are 

 important for understanding the history and current status of geologic systems. 

 The understanding is significant to a variety of issues, including predicting 

 and planning for coastal hazards and engineering design of coastal structures. 



Three principal time scales are important in assessing the geologic and 

 geomorphic changes of coasts. These include: (1) modern studies, which are 

 based largely on field data or laboratory and office experiments of 

 environmental processes; (2) historic studies, which are based largely on 

 information from maps, photography, archives, and other sources; and 

 (3) studies of paleoenvironments, which are based largely on stratigraphy and 



Geomorphic refers to the description and evolution of the earth's topographic features - 

 surficial landforms shaped by winds, waves, ice, flowing water, and chemical processes. 



Chapter 1 Introduction 



