| 释义 |
onlap Geol.|ˈɒnlæp|
[f. on adv. + lap v.2, after offlap.]
A progressive increase in the lateral extent of conformable strata in passing upwards from older to younger strata, so that each stratum is hidden by the one above; a set of strata exhibiting this.
1947F. A. Melton in Bull. Amer. Assoc. Petroleum Geologists XXXI. 1869 The writer proposes that the simpler name marine-onlap, which has already been used by various authors, be substituted for the more cumbersome term used by Grabau. Marine-onlap is thus used to describe the regular progressive pinching-out of marine strata above an unconformity..in such a way that the younger beds extend farther landward than do the older beds which lie beneath... The term terrestrial-onlap can be used in connection with terrestrial formations. 1955Sci. Amer. Mar. 84/2 When the sea advanced, under the simplest conditions the new deposits overlapped the older in a shoreward direction—a process called onlap. 1968R. W. Fairbridge Encycl. Geomorphol. 340/1 The ‘Schooley Peneplain’ of the Appalachians..dips unmistakably under the mid-Tertiary transgressive onlap of the Atlantic Coastal Plain. |