Proterozoic


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Related to Proterozoic: Cambrian, Geological time scale

Proterozoic

that period of geological time lasting from some 2600 million to 589 million years ago; the part of Cryptozoic time excluding the Archaean Period. Fossils dating from this period are mainly CYANOBACTERIA.
References in periodicals archive ?
The west-northwest trending belt includes rocks of the Kambui supergroup and is surrounded by gneiss granites of the early proterozoic period in the north and the biotite granite gneisses in the south.
My PhD was concerned with Proterozoic tectonics, trying to understand the broad scale controls on the evolution of the upper part of the Earth 1-2 billion years ago.
In particular, AEM offers an opportunity to define graphite within areas where shallow cover sequences obscure the host Lower Proterozoic metasediments.
These authors also found a few grains in the same sample and in a nearby sample that produced Mesozoic and Paleozoic spot ages, which presumably result from mixing Proterozoic and Cenozoic generations of monazite during analysis (cf.
These features are similar to those around major Proterozoic unconformity-style uranium deposits elsewhere, such as Cigar Lake (209 Mlb at 17% U3O8) in the Athabasca Basin in Canada and the Ranger Mine (350 Mlb at 0.
Down to a depth of 6842 m the SG-3 section is represented by sedimentary-volcanic rocks of the Lower Proterozoic Pechenga complex, below gneisses and amphibolites of the Archaean basement occur.
The new extinction mechanism of hydrogen sulfide releases might also have prevented life from making the evolutionary jump onto land during the Proterozoic period 0.
65 Mesozoic Createous Jurassic Triassic 248 Paleozoic Permian Carboniferous Devonian Silurian Ordovician Cambrian 543 Late Ediacaran NEWCOMER: Proterozoic Cryogenian The new period stretches from 600 to 544 million years ago.
1991; Petersell & Levchenkov 1994) suggested that the South Estonian granulites were more likely early Proterozoic than Archaean in age.
Pettigrew says the Nipigon Plate is an "interrupted third failed arm of a proterozoic arm that is one billion years old.
The southern Appalachian Blue Ridge is composed predominantly of late Proterozoic metaclastic and metavolcanic units overprinted by a mid-Paleozoic dynamothermal event that recrystallized these units to a range of metamorphic grades.