66 



GEOMORPHOIOGY: 



ism may all contribute to formation of a single com- 

 plex mountain. 



The life cycle of complex mountains cannot be 

 given in general terms. It depends upon the multi- 

 plicity of factors that produce each complex moun- 

 tain. However, the factors cause a peculiarity of these 

 mountains in that the initial stages tend to be absent, 

 perhaps because the complexity is the result of pro- 

 gressive development. Otherwise, the cycle is charac- 

 terized by youth, maturity, and old age. 



Complex mountains are not always easy to segre- 

 gate from blocks or horsts. On the other hand, they 

 rarely are confused with folded mountains. The pos- 

 sible confusion of rejuvenated folded mountains does 

 not exist, because new uplift or folding creates a com- 

 plex mountain. They may be confused with faulted 

 mountains, because faulting often is a major feature 

 of complexity. Therefore, complex mountain erosion 

 often sculptures trapezoidal to triangular facets. On 

 the other hand, complex mountains are characterized 

 by lack of the clear, distinct, or unique features of 

 vulcanism, folding, or faulting. Rather, land forms 

 have the perplexing characteristics of two or more 

 processes. Therefore, when lack of clarity is observed, 

 the land form may well be a complex mountain. 



IDENTIFICATION OF LAND FORMS 



The diagnosis of land forms is not as simple as 

 previous discussions might imply. Often, basically 

 uncomplicated land forms are not completely typical 

 end products of the processes that created them. To 

 be sure of what occurred, detailed study by a geolo- 

 gist often is required. However, many other land 

 forms are fairly distinctive; one of the major con- 

 structive processes appears clear, especially during 

 youth, and one or even more of the destructive proc- 

 esses may be apparent. In such cases, if the features 

 discussed in this chapter are understood, they can be 

 applied to a local situation and should lead to a fairly 

 accurate picture of the general land forms of a local- 

 ity. However, any help that can be obtained should 

 be used. Such help is often available in detailed 

 studies by geologists. 



The more detailed geological reports are of two 

 types, local and statewide. Both types have maps and 

 sometimes detailed descriptions of the particular 

 places. They emphasize the distribution of such 

 things as fault lines, rock types, and other informa- 



tion that allows more precise identification of land 

 forms. To obtain such reports, one can either consult 

 the library of a nearby college or university, or write 

 to the appropriate state agency. State agencies such 

 as Departments of Natural Resources or Divisions of 

 Mines know if such publications are available. For 

 example, the California State Division of Mines sells 

 individual sheets of a colored geological map of Cali- 

 fornia. Like many other publications, the California 

 map is subdivided into segments that consider local 

 areas. 



Less detailed sources of information are provided 

 for much larger geographic areas. This information 

 is generally summarized in a hierarchy of land form 

 classification on a geographic basis. As in the classifi- 

 cation of plants and animals, these land form sum- 

 maries have all-inclusive categories containing a 

 series of progressively smaller subdivisions. Such 

 publications are of some local interest. Each places 

 a given area into its general pattern of gross past 

 geological history. Sometimes local land forms are 

 described in detail. I 



MORPHOGENIC REGIONS 



Additional help in characterizing areas is gained 

 from the concept of morphogenic regions. Such re- 

 gions are diagnosed on the basis of the predominant 

 agents of erosion. Because agents of erosion reflect 

 climate, morphogenic regions are associated with 

 climate, vegetation, and soils. Table 4.1 displays 

 these associations. In the table agents of erosion are 

 rated as to their relative effects: maximum (1), mod- 

 erate (2), and minimum (3). In the case of soil forma- 

 tion an "x" is used to indicate which processes are of 

 most importance in each region. The processes of soil 

 formation are explained in more detail in the next 

 chapter. Gleization is a soil-forming process charac- 

 teristic of arctic areas, podsolization of cool moist 

 climates, laterization of warm and moist climates, 

 and calcification of arid areas. 



IMPORTANCE OF IDENTIFICATION 



Although correct identification of land forms is not 

 always possible, this is not as unfortunate as it might 

 appear. Insofar as natural history relationships be- 

 tween organisms and their environment are con- 

 cerned, precise designation of land forms is unneces- 

 sary. Usually, the only requirement is the nature of 



