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48 terms

Geology Ch 10

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Archean crust-forming processes continued into the Proterozoic but
at a considerably reduced rate
Archean cratons served as
nuclei about which Proterozoic crust accreted
one large landmass that formed by Archean craton-forming
Laurentia
Laurentia consisted mostly of
North America and Greenland
major events in the Proterozoic evolution of Laurentia
an Early Proterozoic episode of amalgamation of cratons, Middle Proterozoic igneous activity, and the Middle Proterozoic Grenville orogeny and Midcontinent rift
by the Late Proterozoic, there were probably
three or more continents
the three continents of the Late Proterozoic
Laurasia, East Gondwana, West Gondwana
Laurasia consisted of
Laurentia and what is now Europe and most of Asia
East and West Gondwana may have
united in the latest Proterozoic to form Gondwana
Greenstone belts formed during the
Proterozoic but at a reduced rate
from their Archean counterparts, greenstone belts of the Proterozoic differ in
detail
opiolite sequences mark
convergent plate margins
opliolite sequences are first well documented from
the Early Proterozoic
present-day style of plate tectonics seems to have been established during the
Early Proterozoic
Quartzite-carbonate-shale assemblages are known from
the Late Archean
Quartzite-carbonate-shale assemblages became common in
Proterozoic rocks
Quartzite-carbonate-shale assemblages in Proterozoic rocks were deposited on
passive continental margins and in intracratonic basins
occured during the Early and Late Proterozoic
widespread glaciation
through the Proterozoic, the atmosphere became
progressively richer in free oxygen
largely responsible for oxygenation of the atmosphere in the Proterozoic
photosynthesizing cyanobacteria
besided photosynthesizing cyanobacteria, this also contributed some oxygen
photochemical dissociation of water vapor
when were most of the world's iron ores deposited as banded iron formation
2.5 to 2.0 billion years ago
first continental beds were deposited
1.8 billion years ago
widespread occurrence of oxidized iron in sedimentay rocks indicates
an oxidizing atmosphere
only known life-forms from the Early Proterozoic
unicellular prokaryotes
first appeared during the Middle Proterozoic
eukaryotic cells
oldest fossils of multicellular organisms are
carbonaceous impressions, probably of algae, in rocks 1 billion and 700 million years old
Late Proterozoic Ediacaran faunas include
the oldest well-documented animal fossils other than burrows
in the Late Proterozoic, animals were
widespread
animals of the Late Proterozoic were all
soft-bodied
Late Proterozoic animals were soft bodied
fossils are not common in the Late Proterozoic because
most of the world's iron ore production is from
Proterozoic banded iron formations
other important resources of the Proterozoic
nickel, platinum, and a variety of materials mined from pegmatites
oldest well-documented fossil animal occur in the
Ediacaran fauna
Proterozoic Eon began
2.5 billion years ago
large landmass consisting mostly of North America and Greenland the formed during the Proterozoic
Laurentia
widespread Middle Proterozoic igneous rocks consist mostly of
ash flow deposits and plutons
last major North American orogen to for during the Proterozoic was teh
Greenville orogen
thick accumulations of basaltic lava flows forming extensive lava plateaus occur in the
Midcontinent rift
Archean and Proterozoic greenstone belt rocks are
similar
and exception to Archean and Proterozoic greenstone belt rocks' similarity is that
Proterozoic contain little or no ultramafic rock
most common associations of Proterozoic rocks are
quartzite-carbonate-shale
lithified glacial deposits
tillite
banded iron formations
BIFs
BIFs were deposited during
Early Proterozoic
presence of red beds during the Proterozoic indicates
the atmosphere contained some free oxygen
most important event in the evolution of life during the Proterozoic was the appearance of
eukaryotic cells
evidence for the origin of eukaryotics cells comes from the study of
present-day organisms