| 单词 | marker horizon |
| 释义 | > as lemmasmarker horizon marker horizon n. Geology a layer of sedimentary rock possessing distinctive characteristics (as particular minerals, chemicals, or fossils) which enable it to be recognized at different locations; a marker bed. ΚΠ 1947 Engin. & Mining Jrnl. Jan. 80/2 Within the granite gneiss occurs a prominent and persistent layer of quartzite, varying in thickness from 100 to 700 ft... The disposition of this quartz-rich ‘marker horizon’ reveals that the bedrock has been arched to form two low domes. 1978 Jrnl. Ecol. 66 302 Correlation of dates between the Coolteen cores..was achieved on the basis of clear litho- and bio-stratigraphic marker horizons. 1990 C. Pellant Rocks, Minerals & Fossils 24 Wind systems can carry volcanic dust thousands of kilometres, high in the atmosphere, and the geological record contains many thin ‘marker-horizons’ of ash and clay from ash falls. < as lemmas |
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