首页 > Term: geologic time unit
geologic time unit
A division of time traditionally distinguished on the basis of the rock record as expressed by a time-stratigraphic unit. Geochronologic units in order of decreasing rank are eon, era, period, epoch, and age. Names of periods and units of lower rank are the same as those of the corresponding time-stratigraphic units; the names of some eras and eons are independently formed.
- 词性: noun
- 行业/领域: 采矿
- 类别 一般矿业; Mineral mining
- Government Agency: USBM
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创建者
- ed.young
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(Milwaukee, United States)