DEFTNIT]0X OV META.MORPIIISM 383 



According to A"an Iliso (190-J, page 3:3), inetamorpliif^in ''means any 

 change in the constitution of any rock." He therefore includes all 

 weathering processes; all other changes produced by vadose waters; tlie 

 cementation of sediments or pyroclastic rocks ; as well as rock changes due 

 to heightened pressure or temperature, or both. Basing his work on the 

 theses tliat (page 40) "the only workable classification of metamorj)irLsm 

 is geological," and that (page 43) depth is ''the most important ot the 

 influences wliich deteiinine the character of the alterations of rocks," \'an 

 Hise considers these in terms of his zones of katamoi'phism and anamor- 

 phisni.- 



Chamberlin and Salisbury (1906, volume 1, pages 436 and 432) apply 

 the term "metamorphism" to the "more profound changes'' in rocks, the 

 "more profound changes of induration and composition . . . essentially 

 reconstruction." They exclude both weathering and mere cementation 

 from the list of metamorphic processes, though pointing out that meta- 

 morphism is often "but an extension and intensification" of the change 

 called induration or cementation. As usual in modern textbooks, dynamic 

 action is emphasized; Chamberlin and Salisbury do not mention static or 

 load metamorphism. 



Haug (1907, pages 176-177, 185) does not give a formal definition, 

 but states that high temperature, high pressure, and the presence of water 

 are essential to true metamorphism. He apparently excludes from it 

 hydration, oxidation, cementation, and decalcification. He divides meta- 

 morphic processes into two classes — "contact" and "general." Like Ter- 

 mier, he denies the po^ver of dynamic metamorphism to do more than 

 mechanically change a rock or to affect its mineralogical composition. 

 Haug adopts Michel Levy's view that contact metamorphism becomes con- 

 fluent with "^general" metamorphism as the depth increases. 



In the last edition of his "Elemente der Gesteinslehre," Eosenbuscli 

 (1910, page 72) excluded weathering and decomposition in general from 

 the list of metamorphic processes, though stating (page 578) that dia- 

 genesis is transitional into metamorphism. He defined diagenesis as com- 

 prising all changes in a sediment during and after its deposition until 

 the stage of consolidation (Yerfestigung) is reached; diagenesis may even 



2 When used geologically — that is, in reference to depth below the earth's surface — 

 the "katamorphic" and "anamorphic" of Van Hise have respective meanings nearly oppo- 

 site to the "katogen" and "anogen" of Becke (1892, page 207), or Kalkowsky (ISSG, 

 page 29), or Haidinger (1850, page 301). See also B. Cotta's "Geologische Fragen," 

 Freiberg. 1858, page 94, wlicn-e the author fornKilly adopts the latter pair of words, 

 coined by Haidinger, to express a dichotqmous division of all rock alterations, lieith 

 and Mead (1915, page xix) have so x-edelined "katamorphisui" and •'anamorphism" that 

 these processes are therel)y to l)e considered as having no necessary relation to depth at 

 all. Once again it is ch-ar li(,\v tbe student ot Ww fudire will be troubled by the llux 

 of definition and usage. 



