| 释义 |
Pre-ˈCambrian, a. Geol.
Also pre-Cambrian, Precambrian.
[pre- B. 1.]
Of, pertaining to, or designating the time before the beginning of the Cambrian period and Palæozoic era, present-day rocks of which are marked by an almost complete absence of fossils. Also ellipt., the Pre-Cambrian rocks or period.
1864J. W. Salter in Geol. Mag. I. 290 The author suggests that the syenitic trap of St. David's is a part of the old pre-Cambrian land. 1875J. Croll Climate & T. xx. 343 The length of time embraced by the pre-Cambrian ages of geological history. 1910Lake & Rastall Text-bk. Geol. xvii. 292 Everywhere in the British Isles there is a marked unconformity between the pre-Cambrian and the later deposits. 1915C. Schuchert Text-bk. Geol. II. xxvii. 540 The result..serves to make prominent the two most significant and distinctive features of the pre-Cambrian: (1) the wide-spread crustal revolutions,..and (2) the profound depth to which erosion has planed. 1921A. W. Grabau Textbk. Geol. II. xxx. 198 (heading) Summary of the pre-Cambrian of the Canadian region. 1951Auden Nones (1952) 71 That the red pre-Cambrian light Is gone like Imperial Rome Or myself at seventeen. 1959Times 18 June (Queen in Canada Suppl.) p. xiii/2 The gnarled Precambrian surface of the Canadian Shield, the low hills of the Mackenzie valley are all foreign to the Yukon. 1969E. W. Morse Fur Trade Canoe Routes of Canada v. 57 At the upper end of Lac des Alumettes the voyageurs came..into close contact with the granite of the Precambrian Shield, rising straight from the water. 1971Nature 25 June 498/1 The Pre-Cambrian covers 85% of the total length of geological time and is the longest geological division. 1977Jrnl. R. Soc. Arts CXXV. 406/1 Uranium deposits..occur in well defined provinces mainly in Precambrian terrain. |