| 释义 |
Maestrichtian, a. Geol.|mɑːˈstrɪçtɪən|
Also Maastrichtian.
[ad. F. maestrichtien (A. Dumont 1849, in Bull. de l'Acad. R. d. Sci. [etc.] de Belgique XVI. ii. 360), f. Maestricht (now Maastricht), the name of a city in SE. Holland; see -ian.]
Of, pertaining to, or designating a division of the Upper Cretaceous in Europe that is now regarded as a stage lying next below the Danian. Also absol.
1885A. Geikie Text-bk. Geol. (ed. 2) 834 In the Cotentin, a limestone with Baculites anceps, Scaphites constrictus, and other fossils has been paralleled with the Maestricht chalk (Maestrichtian sub-stage). 1931Gregory & Barrett Gen. Stratigr. xi. 171 The Senonian deposits in the N.E. of France and Belgium were those of a shallow sea, such as the phosphatic chalks of the Campanian and the limestone ‘tuffau’ of the Maastrichtian. 1967D. H. Rayner Stratigr. Brit. Isles x. 337 Maastrichtian chalk is rare in Britain but small remnants of the lower zone (Belemnitella lanceolata) are known from the Norfolk coast and north-eastern Antrim. 1971Nature 19 Feb. 553/2 Although disputed by some, the latest Cretaceous and earliest Tertiary (Maestrichtian and Danian stages) have generally been recognized as a brief interval during which many organisms underwent a severe attenuation in diversity or became extinct. 1975Ibid. 6 Mar. 50/1 By about 70 Myr ago (late Cretaceous: Maastrichtian) there seems to have been a gap large enough to have prevented east–west migration of marine reef colonies. |