| 释义 |
tonstein Geol.|ˈtɒnstaɪn|
[a. Ger., lit. ‘clay stone’.]
A rock composed mainly of kaolinite which is commonly found in association with certain coal seams, or a thin band of such a rock (see quots.).
1961I. A. Williamson in Mining Mag. CIV. 9 Tonsteins are essentially argillaceous rocks containing kaolinite in a variety of forms together with occasional detrital and carbonaceous material. 1971Nature 6 Aug. 371/2 The thin, curious, kaolinitic bands called tonsteins discovered more recently in the coalfields of Western Europe have provided welcome additional markers for coalfield correlation. |