Lecture 11 - The Proterozoic Eon

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Historical Geology
Lecture 11 The Proterozoic Eon
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Historical Geology
Outline
I Proterozoic Timeline II Tectonics
Overview A) Continental Growth B) Wilson
Cycle Tectonics III Paleoproterozoic Laurentia
(North America) A) Orogenies (Convergence) B)
Rifting (Divergence) C) Sedimentation D) Clima
te IV Mesoproterozoic Laurentia (North
America) A) Orogenies (Convergence) B) Rifting
(Divergence) C) Sedimentation D) Climate V Ne
oproterozoic Laurentia (North America) A) Orogen
ies (Convergence) B) Rifting (Divergence) C) S
edimentation D) Climate VI The Proterozoic
Outside Laurentia
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Historical Geology
The Proterozoic Eon
0.545 bya
1.0 bya
1.6 bya
2.5 bya
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Historical Geology
The Proterozoic Eon Tectonics Overview

• growing cratons
• lateral plate tectonic movements
• rifting and sea-floor spreading
• wide continental shelves
• epeiric seas

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The Proterozoic Eon Aggregating Cratons
accretion - addition of
crustal materials to
continental margins
aggregation bringing
together and consolidation
of cratonic elements
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Historical Geology
The Proterozoic Eon Early Epeiric Seas
epeiric sea - a shallow sea flooding the
continental craton
Erikkson, et al., 1998
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Historical Geology
The Proterozoic Eon Sedimentation Overview

• Carbonates appear
• Banded Iron Formations peak/disappear
• Red Beds
• Passive Margin Sedimentation

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Historical Geology
The Proterozoic Eon Carbonate Sedimentation
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The Proterozoic Eon Banded Iron Formations
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The Proterozoic Eon Red Beds
oxidation 4Fe 3O2 ---gt 2Fe2O3 iron
oxygen -gt iron oxide

• hematite
• limonite

Red Shale Chuar Group (Grand Canyon)

• laterite soils

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Historical Geology
Paleoproterozoic Laurentia Orogenies

• Torngat (2.1-1.75 Ga)
• Taltson-Thelon (2.0-1.9 Ga)
• Penokean (2.0-1.8 Ga)
• Wopmay (1.97-1.84 Ga)
• Cape Smith-New Quebec (1.9-18 Ga)
• Trans-Hudson (1.88-1.79 Ga)

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Historical Geology
Paleoproterozoic Laurentia Slave Province
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Paleoproterozoic Laurentia Slave Province
Aulacogens

• Athapuscow Aulacogen
• Bathhurst Aulacogen

Irving, et al., in press
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Historical Geology
Paleoproterozoic Laurentia Slave Province -
Wopmay Orogen
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Historical Geology
Paleoproterozoic Laurentia Superior Province
Young, 2002
Ojakangas, et al., 2001
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Historical Geology
Paleoproterozoic Laurentia Superior Province -
Huronian Supergroup
2.5 - 2.2 Ga
Gowganda Formation Huronian Supergroup
Gowganda Tillite
Young, 2002
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Historical Geology
Paleoproterozoic Laurentia Glaciation
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Historical Geology
Paleoproterozoic Laurentia Superior Province -
Animikie Group
2.2 - 1.8 Ga
Young, 2002
Ajubik Quartzite Animikie Group
Banded Iron Formation Animikie Group
Kona Dolostone Animikie Group
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Historical Geology
Paleoproterozoic Laurentia Superior Province -
Penokean Orogeny
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Historical Geology
Paleoproterozoic Laurentia Superior Province
Cross Section
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Historical Geology
Paleoproterozoic Laurentia Trans-Hudson Orogen
Schwerdtner and Cote, 2001
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Historical Geology
Mesoproterozoic Laurentia Events

• Elsonian Orogeny
• Yavapai Orogeny
• Mazatzal Orogeny
• Mid-Continent Rifting
• Grenville Orogeny
• Assembly of Rodinia

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Historical Geology
Mesoproterozoic Laurentia Yavapai and Mazatzal
Orogenies

• Series of orogenies
• 1.8 - 1.6 Ga
• Vishnu Schist

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Historical Geology
Mesoproterozoic Laurentia Grand Canyon Region
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Historical Geology
Mesoproterozoic Laurentia Grand Canyon Region
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Mesoproterozoic Laurentia Mid-Continent Rift

• 1.2-1.0 Ga
• Keweenawan Supergroup

Ojakangas and Dickas, 2002
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Mesoproterozoic Laurentia Grenville Orogeny
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Mesoproterozoic Era Rodinia

• S W E A T
• A U S W U S

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Mesoproterozoic Era Rodinia SWEAT
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Mesoproterozoic Era Rodinia AUSWUS
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Neproterozoic Laurentia

• Breakup of Rodinia
• Panthalassic Ocean (proto-Pacific)
• Iapetus (proto-Atlantic)
• Varangian Glaciation

Eykes and Januszczak, in press
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Neproterozoic Laurentia Breakup of Rodinia
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Neproterozoic Laurentia Panthalassa
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Neproterozoic Laurentia Grand Canyon Supergroup
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Neproterozoic Laurentia Late Proterozoic Rifting

• Breakup of Rodinia
• Panthalassic Ocean (proto-Pacific)
• Varangian Glaciation

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Neproterozoic Laurentia Late Proterozoic Rifting
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Neproterozoic Laurentia Varangian Glaciation
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Historical Geology
Neproterozoic Laurentia Varangian Glaciation
Knoll, 2000
Knoll, 2000
Jacobson and Kaufmann, 1999
OXYGEN Heavy Oxygen-18 is incorporated into
minerals. More Oxygen 18 during low
temperatures.
CARBON 12/CARBON 13 Plants use the lighter
isotope Carbon 12 in photosynthesis. The lower
relative abundance of Carbon 13 means the plants
were worse off (dying). Evidence in cap
carbonates
STRONTIUM Increased Sr86/87 ratio due to
increased weathering during glaciation.
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Neproterozoic Era Snowball Earth
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Neproterozoic Era Snowball Earth
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Neproterozoic Era Snowball Earth
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The Precambrian Outside North America