How to use in-sentence of “proterozoic”:
+ The continental crust is mainly made of ArcheanArchaean, Proterozoic and some Palaeozoic granites and gneisses.
+ The Ediacaran is the last period in the Proterozoic eon.
+ Classically, the boundary between the Proterozoic and the Paleozoic was set at the base of the Cambrian period when the first fossils of animals known as trilobites appeared.
+ Eukaryotes evolved in the Proterozoic eon.
+ It lies in the middle Proterozoic eon before the Ediacaran period.
Example sentences of “proterozoic”:
+ Those greenstone belts which formed in ancient oceans are now found on land in Archaean and Proterozoic cratons between granite and gneiss bodies.
+ But several hundred kinds of Proterozoic metazoa have been discovered in the Ediacaran.
+ Around them are several Proterozoic volcanic belts and sedimentary basins.
+ The time before the Phanerozoic, formerly called the “Precambrian”, is now divided into the Hadean, Archaean and Proterozoic eons.
+ It became iron oxide and made huge deposits as Banded iron formationbanded iron rock from the Archaean and Proterozoic eras.
+ The exact time of the boundary between the Phanerozoic and the Proterozoic is slightly uncertain.
+ In contrast to the deep-water deposits of the Archean, the Proterozoic features many strata that were laid down in extensive, shallow epicontinental seas; furthermore, many of these rocks are less Metamorphic rockmetamorphosed than Archean-age ones, and plenty are in fact unaltered.
+ Those greenstone belts which formed in ancient oceans are now found on land in Archaean and Proterozoic cratons between granite and gneiss bodies.
+ But several hundred kinds of Proterozoic metazoa have been discovered in the Ediacaran.
+ Around them are several Proterozoic volcanic belts and sedimentary basins.
+ We now know that ice ages have happened a number of times in the past, the greatest and longest of which took place in the Proterozoic era, before multi-cellular eukaryotes evolved.
+ In the second half of the 20th century, a number of fossil forms have been found in Proterozoic rocks, but the boundary of the Proterozoic has remained fixed at the base of the Cambrian—currently placed at 542 Ma.
+ The geologic record of the Proterozoic is much better than that for the preceding Archaean.
+ The Proterozoic Eon extended from 2500 million years ago to 541 mya.