archean eon造句

例句与造句

1. The first large cratonic landmasses formed during the Archean eon.
2. Instead of being based on stratigraphy, the beginning and end of the Archean Eon are defined chronometrically.
3. The orogeny affected adjacent regions of northern Minnesota and Ontario in the Superior province and brought the Archean Eon to a close.
4. Carbon found in 3.8 billion year old rocks ( Archean eon ) from islands off western Greenland may be of organic origin.
5. This will provide previously unknown evidence for the conditions in early Earth and allow testing of ideas of how the planet evolved through the Hadean and Archean eons.
6. It's difficult to find archean eon in a sentence. 用archean eon造句挺难的
7. Recent evidence suggests the oceans may have begun forming as early as 4.4 Ga . By the start of the Archean eon they already covered the Earth.
8. In contrast to Proterozoic Eon rocks, Archean Eon rocks are often heavily metamorphized deep-water sediments, such as graywackes, mudstones, volcanic sediments, and banded iron formations.
9. Earth was very hostile to life before 4.2  4.3 Ga, and the conclusion is that before the Archean Eon, life as we know it would have challenged.
10. A 2012 study looked at the imprints made by falling raindrops onto freshly deposited volcanic ash, laid down in the Archean Eon 2, 700 Ma in the Ventersdorp Supergroup, South Africa.
11. As no older rocks could be found, it was generally assumed that the Earth had remained molten until this date, which defined the boundary between the earlier Hadean and later Archean eons.
12. It can, however, be said that the very beginnings of life could have been taken earlier, while the conditions necessary to sustain it could only have been possible in the Archean Eon.
13. The geology of the Jefferson River and the surrounding mountain ranges includes some of the oldest rocks found in North America, dating back to the Archean Eon, 2.7 billion years ago.
14. The collision of the gneissic Minnesota River Valley ( MRV ) subprovince onto the southern edge of the Superior province was another process in the slow change in tectonics which marks the end of the Archean Eon.
15. The presence of an ocean, first dating from the late Hadean, would suggest the start of life in the following Archean Eon rather than in the Hadean Eon depended on the presence of an ocean ..
16. Before the Rove sediments were laid down, during the Archean Eon, the Algoman orogeny added landmass along a border from South Dakota to the Lake Huron region; this boundary is the Great Lakes tectonic zone.
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