Here is a list of terms and cincepts that may be used as a study guide on the Archean stratigraphy of North America.

PC tectonic collage of North America - 5 different elements

Archean perimobile continents

Archean: greenstone belts & high grade metamorphic terranes

Greenstone protolith

2 age groups: >3.0 Ga and <3.0 Ga (2.6-2.8 Ga)

greenstone belt generalizations synforms

Greenstone Belt Stratigraphy

1. lower ultramafic-mafic group, 2. middle mafic-felsic calc-alkaline group, 3. upper sedimentary group

Archean Carbonates seawater chemistry couldn't be preserved

BIF facies: 1. oxide-hematite & magnetite, 2. carbonate -siderite, 3. sulfide- pyrite, 4. silicate- greenalite & minnesotite

BIF & Phanerozoic Fe rich rock differences

1. goethite, 2. chamosite, 3. glauconite, 4. marcasite

comparing BIF & Phanerozoic Fe rocks

Archean BIF "Algoma type Proterozoic BIF "Superior type"

High Grade Terranes or Gneiss Belts

1. quartzofeldspathic or gray gneiss

2. metasupracrustal rocks

3. metamorphosed layered igneous intrusions

generalizations about gneiss belts diopthorites

high grade terranes very complex structurally intensely deformed

Amitsoq Gneiss & Uivalk Gneiss Isua Amphibolite Sr87/Sr86 >0.704

Implications of: high grades greenstones

possible relations: 1. high grades older (ensilaic greenstone), 2. greenstone older (simatic crust), 3. both rocks contemporaneous

Archean tectonic Models: 1. classical, 2. uniformitarianism, 3. actualistic

Archean Conditions

1. liquid water

2. <30°C

3. geothermal gradient

4a. lower luminosity of sun 4b. higher albedo

5. total amount of insolation & absorption affect erosion rate

6. atmosphere composition

7. oxygen

8. chemical weathering

9. physical weathering

10. Archean tectonism

11. dominant clastic lithologies

12. 3 broad sedimentary facies: A. turbidite/pelagic, B. shelf/peritidal/terrestrial, C. starved basin

13. Archean Life 6 types from North Pole, Australia