دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: the theory that the earths landforms assumed their present configuration in a brief episode at the beginning of geologic history-possibly in a single great catastrophic event-and have remained relatively unchanged since that time. Compare uniformtarianism. catcher n: a device fitted into a junk basket that retains the junk picked up by the basket catch samples v: to obtain cuttings for geological information as formations are penetrated by the bit The samples are obtained from drilling fluid as it emerges from the wellbore or, in cable-tool drilling, from the bailer. Cuttings are carefully washed until they are free of foreign matter, dried, and labelled to indicate the depth at which they were obtained.

n: the geologic principle that the processes that are at work today on the earth are the same as, or very similar to, the processes that affected the earth in the past. The principle was formulated in 1785 by James Hutton, a Scottish geologist. It became an accepted doctrine with the publication in 1830 of English geologist Charles Lyells book Principles of Geology. Also called gradualism. Compare catastrophism. spills, coordinates individual and state efforts to rescue and rehabilitate oiled birds, and administers federal aid programs. Address: MS 634 Arlington Square, 1849 C Street NW;Washington, DC 20240;(703) 358- 1714. United States Geological Survey (USGS)