| 释义 |
ravinement Geol.|rəˈviːnmənt|
[a. F. ravinement gullying.]
An unconformity in river or shallow marine sediments caused by interruption of deposition by erosion.
1921L. D. Stamp in Geol. Mag. LVIII. 109 A ‘ravinement’ may be defined as an irregular junction which marks a break in sedimentation... Although one of the commonest of geological phenomena, there is no English word which expresses quite so aptly the relationship. Ibid., The period between two successive ‘ravinements’ constitutes a ‘cycle of sedimentation’. 1923― Introd. Stratigr. i. 17 When such an unconformity is traced laterally into a continuous series of marine deposits it is frequently found that, although the bedding of the upper series is parallel to that of the lower, there are signs that the sea, in depositing the upper series, has slightly eroded the top of the lower series. Such an erosion line is termed a ‘ravinement’. 1969Bennison & Wright Geol. Hist. Brit. Isles i. 8 In the field an unconformity can..be proved because the erosion surface or ravinement is conspicuous. |