1. GEOL 3045: Planetary Geology Lysa Chizmadia Formation of the Moon Lysa Chizmadia Formation of the Moon

2. Lunar Eclipses Images from: http://en.wikipedia.org/wiki/Lunar_eclipse

3. 20 Feb 2008 http://sunearth.gsfc.nasa.gov/eclipse/LEmono/TLE2008Feb21/TLE2008Feb21.html

4. Formation Theories FFission: Moon was originally part of the Earth & somehow separated early FProblem: compositions not ~ enough FCapture: Moon was created somewhere else and captured by Earth’s gravity FProblem: O-isotopes identical FMutual Accretion: They both formed together out of the same materials FProblem: Moon has little or no core FBig Splash: ~Mars-sized bolide hit Earth & Moon formed from ejecta ring FFits O-isotopes, trace elements & low density of Moon FFission: Moon was originally part of the Earth & somehow separated early FProblem: compositions not ~ enough FCapture: Moon was created somewhere else and captured by Earth’s gravity FProblem: O-isotopes identical FMutual Accretion: They both formed together out of the same materials FProblem: Moon has little or no core FBig Splash: ~Mars-sized bolide hit Earth & Moon formed from ejecta ring FFits O-isotopes, trace elements & low density of Moon

5. Big Splash (1/3) FImpactor ~ size of Mars FCalled Tethys FCollided ~4.4 Ga FSprayed crust & some of mantle into space FBoth proto-Earth & Tethys molten FCore of impactor incorporated into Earth’s core FImpactor ~ size of Mars FCalled Tethys FCollided ~4.4 Ga FSprayed crust & some of mantle into space FBoth proto-Earth & Tethys molten FCore of impactor incorporated into Earth’s core Images from: http://www.psi.edu/hartmann/pic-cat/earth.html

6. Big Splash (2/3) FEjecta from impact forms ring around molten Earth FBoth have magma oceans FRing coalesces into Moon FCrust of both bodies cool down FNo longer magma oceans FMoon sweeps up rest of ring material FEjecta from impact forms ring around molten Earth FBoth have magma oceans FRing coalesces into Moon FCrust of both bodies cool down FNo longer magma oceans FMoon sweeps up rest of ring material Images from: http://www.psi.edu/hartmann/pic-cat/earth.html

7. Big Splash (3/3) FVolcanism on Moon FLate Heavy Bombardment FVolcanism subsides on Moon FVolcanism on Moon FLate Heavy Bombardment FVolcanism subsides on Moon Images from: http://www.psi.edu/hartmann/pic-cat/earth.html

8. Late Heavy Bombardment F3.8 - 4.1 Ma FBasin-forming impacts on Moon, Earth, Mercury, Venus, Mars FE.g. Caloris Basin, Mare Basins FMaterials sent in to inner solar system by perturbations from Giant Planets F3.8 - 4.1 Ma FBasin-forming impacts on Moon, Earth, Mercury, Venus, Mars FE.g. Caloris Basin, Mare Basins FMaterials sent in to inner solar system by perturbations from Giant Planets Image from: http://www.daviddarling.info/encyclopedia/L/late_heavy_bombardment.html

9. Lunar Volcanism FMare Volcanism FMost 3.5 - 3.0 Ga FAges range from 4.2 to 1.2 Ga FOccurs mostly on near side FClassification: FHigh Ti basalt FLow Ti basalt FVery low Ti basalt FTi-rich Orange glass F3.7-3.8 Ga FMare Volcanism FMost 3.5 - 3.0 Ga FAges range from 4.2 to 1.2 Ga FOccurs mostly on near side FClassification: FHigh Ti basalt FLow Ti basalt FVery low Ti basalt FTi-rich Orange glass F3.7-3.8 Ga Images from: http://www.psrd.hawaii.edu/Dec00/highTi.html

10. KREEP FK = Potassium FREE = Rare Earth Elements FP = Phosphorus FFormed as a result of magma ocean FHeavy minerals (e.g. olivine, pyroxene) sank FLight minerals (e.g. Plagioclase) rose FFractional Crystallization made magma KREEP-rich FKREEP = incompatible FK = Potassium FREE = Rare Earth Elements FP = Phosphorus FFormed as a result of magma ocean FHeavy minerals (e.g. olivine, pyroxene) sank FLight minerals (e.g. Plagioclase) rose FFractional Crystallization made magma KREEP-rich FKREEP = incompatible Images from: http://www.lunarpedia.org/index.php?title=KREEP

11. Summary FFormed from Big Splash FProblems with other models FMoon ~ Earth composition, but not identical FMoon has low density FMoon & Earth have same O-isotopes FHeavy Late Bombardment FPerturbations from Giant Planets FLunar Volcanism FTi important element FKREEP FLeftovers from fractional crystallization of magma ocean FFormed from Big Splash FProblems with other models FMoon ~ Earth composition, but not identical FMoon has low density FMoon & Earth have same O-isotopes FHeavy Late Bombardment FPerturbations from Giant Planets FLunar Volcanism FTi important element FKREEP FLeftovers from fractional crystallization of magma ocean