expanded during the colder climates of glaciations, perhaps in response to 

 reduced evaporation. Crustal depression occurred with ice advance over the 

 continents; crustal rebound followed deglaciation, further complicating the 

 history of relative sea level changes along coastlines. 



Because of changes in relative sea level, even those coasts not directly 

 glaciated have been affected to some degree. But coasts were affected in 

 differing ways by these processes and events, adding to their geomorphic vari- 

 ability. Such eustatic, climatic, and crustal changes are still occurring to 

 varying degrees in different parts of the world. This subject will be further 

 discussed in the section on relative sea level later in this part of the report. 



Variations in paleoclimate and glacial activity account for much of the vari- 

 ability in geomorphic landforms and processes along coasts. Examples of 

 erosional coasts include fjords, which were produced by the erosive activity of 

 mountain glaciers in conjunction with relative sea level changes. The erosive 

 activity of the mid-latitude North American ice sheets was also integral in the 

 formation of the Great Lakes basins (Hough 1968). As characterized by 

 Shepard (1963), depositional glacial coastlines may consist of tills, moraines, 

 and drumlins. The north shore of Long Island Sound, extending from 

 Connecticut to Massachusetts, displays these features. 



Modern climatic conditions have been well-documented by systematic and 

 accurate meteorological observations in many parts of the world. In some 

 places, such records exist for periods as long as 2 centuries. These form a 

 foundation for a reasonably accurate model of the earth's present climatic 

 patterns and of anticipated trends. The use of satellites for remote sensing of 

 the atmosphere and the development of general circulation models are assist- 

 ing in the interpretation of past and the prediction of future climates. 



Coasts are directly and indirectly affected by modern climatic conditions. 

 Differences in temperature and precipitation influence organisms, vegetation 

 type, and biomass production (Whittaker and Likens 1975). Climatic varia- 

 tion also affects the type and intensity of weathering and the rates of denuda- 

 tion (Langbein and Schumm 1958; Knighton 1984), which in turn influence 

 geomorphic features along coasts. Atmospheric conditions are intimately 

 linked to oceanographic conditions, so that a change in one will cause a 

 change in the other. 



Climatic factors need not operate directly in the coastal zone to be 

 relevant. For example, wind-generated waves in remote offshore areas can 

 eventually reach and affect the coast, and precipitation in inland areas is 

 important in producing and transporting sediment that enters the coastal 

 system. The assessment of climatic factors therefore requires consideration of 

 climatic data from outside, as well as within, the coastal zone. 



Chapter 2 Relevant Processes and Factors 



