| 释义 |
allogenic, a.|æləʊˈdʒɛnɪk|
[f. Gr. ἀλλογενή-ς (see allogeneity) + -ic.]
1. Geol. (See quot. 1888.)
1888F. H. Hatch in J. J. H. Teall Brit. Petrogr. 423 Allogenic (Allothigenic), applied to such minerals as are of more ancient origin than the rocks which they compose. 1893[see authigenic a.]. 1937Wooldridge & Morgan Physical Basis Geogr. xix. 277 Many..of these streams are ‘allogenic’, deriving much of their water from terrains beyond the Chalk outcrops.
2. Ecology. Caused by external factors, opp. autogenic a. (see also quot. 1962).
1931W. B. McDougall Plant Ecol. (ed. 2) xix. 259 Successions that are brought about by the reactions of the plants themselves are sometimes called autogenic successions while those caused by climatic or physiographic factors are called allogenic successions. 1934Geogr. Jrnl. LXXXIII. 499 The further stages in the succession may be brought about by the operation of external factors alone, and when this is so the succession is termed an allogenic succession. 1962H. Hanson Dict. Ecol. 14 Allogenic succession, the kind of succession in which one kind of community replaces another because of a change in the environment which was not produced by the plants themselves, e.g., decrease in soil moisture by improved drainage. |