| 释义 |
euxinic, a. Geol.|juːkˈsɪnɪk|
[f. L. (Pontus) Euxīn-us the Black Sea (see quot. 1937) + -ic.]
Formed in or designating a geological environment in which limited circulation of water has produced stagnant anaerobic conditions; (of an event) giving rise to deposits of this kind, such as black shales.
1937Bull. Amer. Assoc. Petroleum Geologists XXI. 1115 Analyses show the presence in the Black Sea muds of a relatively high proportion of organic matter and various investigators have seen in this fact a possible source for the formation of materials analogous with the black shales of some geological formations... Van der Gracht proposes the term euxinic facies (Pontus Euxinus = Black Sea) for deposits of this type. 1949F. J. Pettijohn Sedimentary Rocks xiv. 458 The true euxinic sediments are exclusively marine and generally rather deep-water. 1963D. W. & E. E. Humphries Termier's Erosion & Sedimentation xi. 232 The preservation of organic matter in these environments tends to produce hydrocarbons. Such environments are known as ‘euxinic’ and have been known for a long time in the Black Sea. 1970R. M. Black Elements Palaeont. xix. 302 Anaerobic bacteria are invoked to explain occurrences of euxinic shales. 1979Nature 25 Oct. 667/1 The ‘euxinic events’ responsible for this facies pattern are all characterised by saline spills or brine invasions, which in turn led to a midwater halocline and a meromictic basin. 1985Ibid. 3 Jan. 13/1 The Hangenberg event, towards the close of the Famennian, was another euxinic black shale event in Europe. |