Using the Moon to Determine the Magnitude of the Inner Solar System Cataclysm and Post-Cataclysm Impact Flux David A. Kring Visiting Scientist Lunar Exploration Initiative Lunar and Planetary Institute Houston, TX 77058 David A. Kring/NAC Lunar Workshop/Feb 2007
Using the Moon to Determine the Magnitude of the Inner Solar System Cataclysm and Post-Cataclysm Impact Flux Why is this important? David A. Kring/NAC Lunar Workshop/Feb 2007
Using the Moon to Determine the Magnitude of the Inner Solar System Cataclysm and Post-Cataclysm Impact Flux Why is this important? ● These events resurfaced the Moon, generating the landscape that we will be exploring David A. Kring/NAC Lunar Workshop/Feb 2007
Using the Moon to Determine the Magnitude of the Inner Solar System Cataclysm and Post-Cataclysm Impact Flux Why is this important? ● These events resurfaced the Moon, generating the landscape that we will be exploring ● Similar events resurfaced the Earth during a critical time when life was first evolving David A. Kring/NAC Lunar Workshop/Feb 2007
Using the Moon to Determine the Magnitude of the Inner Solar System Cataclysm and Post-Cataclysm Impact Flux Why is this important? ● These events resurfaced the Moon, generating the landscape that we will be exploring ● Similar events resurfaced the Earth during a critical time when life was first evolving ● The processes affected all inner solar system planets and will affect the lunar-calibrated crater ages assigned to their surfaces David A. Kring/NAC Lunar Workshop/Feb 2007
Using the Moon to Determine the Magnitude of the Inner Solar System Cataclysm and Post-Cataclysm Impact Flux Why is this important? ● These events resurfaced the Moon, generating the landscape that we will be exploring ● Similar events resurfaced the Earth during a critical time when life was first evolving ● The processes affected all inner solar system planets and will affect the lunar-calibrated crater ages assigned to their surfaces ● A study of these processes on the Moon will have a dramatic affect on our understanding of how the outer solar system formed David A. Kring/NAC Lunar Workshop/Feb 2007
Science Priorities for the Lunar Exploration Initiative The Apollo Legacy – The radiometric ages of rocks from the lunar highlands indicated the lunar crust had been thermally metamorphosed ~3.9 – 4.0 Ga. A large number of impact melts were also generated at the same time. This effect was seen in the Ar-Ar system (Turner et al., 1973) and the U-Pb system (Tera et al., 1974). It was also preserved in the more easily reset Rb-Sr system. (Data summary, left, from Bogard, 1995.) A severe period of bombardment was inferred: The lunar cataclysm hypothesis . David A. Kring/NAC Lunar Workshop/Feb 2007
David A. Kring/NAC Lunar Workshop/Feb 2007
Science Priorities for the Lunar Exploration Initiative Impact-Origin of Life Hypothesis Impact-generated Hydrothermal Systems provided: Crucibles for Pre-biotic Chemistry Habitat for Early Evolution of Life Long Lifetimes Active for 10,000 to several million years How often were these systems produced on early Earth? Preliminary Apollo-era data suggest 20,000 to 40,000 times David A. Kring/NAC Lunar Workshop/Feb 2007
Ar-Ar analyses of impact melts in lunar meteorites are consistent with a cataclysmic bombardment ~3.9 – 4.0 Ga e.g., Cohen, Swindle, & Kring (2000, 2005) David A. Kring/NAC Lunar Workshop/Feb 2007
Ar-Ar analyses of impact melts in lunar meteorites are consistent with a cataclysmic bombardment ~3.9 – 4.0 Ga e.g., Cohen, Swindle, & Kring (2000, 2005) Ar-Ar analyses of impact melts from asteroids suggest the cataclysmic bombardment affected the entire inner Solar System e.g., Bogard (1995), Kring & Cohen (2002) David A. Kring/NAC Lunar Workshop/Feb 2007
Ar-Ar analyses of impact melts in lunar meteorites are consistent with a cataclysmic bombardment ~3.9 – 4.0 Ga e.g., Cohen, Swindle, & Kring (2000, 2005) Ar-Ar analyses of impact melts from asteroids suggest the cataclysmic bombardment affected the entire inner Solar System e.g., Bogard (1995), Kring & Cohen (2002) Siderophile elements in Apollo impact melts suggest the impacting objects came from the Asteroid Belt e.g., Kring & Cohen (2002), Norman et al. (2006) David A. Kring/NAC Lunar Workshop/Feb 2007
Ar-Ar analyses of impact melts in lunar meteorites are consistent with a cataclysmic bombardment ~3.9 – 4.0 Ga e.g., Cohen, Swindle, & Kring (2000, 2005) Ar-Ar analyses of impact melts from asteroids suggest the cataclysmic bombardment affected the entire inner Solar System e.g., Bogard (1995), Kring & Cohen (2002) Siderophile elements in Apollo impact melts suggest the impacting objects came from the Asteroid Belt e.g., Kring & Cohen (2002), Norman et al. (2006) The size distribution of craters on the Moon also suggests the impacting objects came from the Asteroid Belt e.g., Strom et al. (2005) David A. Kring/NAC Lunar Workshop/Feb 2007
Yet, we are still operating in a data poor environment……. We need more lunar samples to determine the magnitude and duration of the bombardment. David A. Kring/NAC Lunar Workshop/Feb 2007
What types of biogenic elements were delivered? How was the composition of the atmosphere altered? How did impacts affect the origin of life & microbial evolution? How did impacts affect complex life (e.g., at K/T boundary)? What are the future impact hazards? David A. Kring/NAC Lunar Workshop/Feb 2007
Nectarian and Early Imbrian Impact Basins Impact Basin Diameter (km) Age (Ga) Imbriam Orientale 930 3.82 – 3.85 ? Basins Early Schrodinger 320 Imbrium 1,200 3.85 ± 0.01 Bailly 300 Sikorsky-Rittenhouse 310 Hertzprung 570 3.89 ± 0.009 Nectarian Basins Serenitatis 740 3.895 ± 0.017 Crisium 1,060 3.89 ? Humorum 820 Humboldtianum 700 implying Medeleev 330 ~70 to 90 million year Korolev 440 bombardment Moscovienese 445 Mendel-Rydberg 630 Nectaris 860 3.89 – 3.91 ? For comparison, Chicxulub’s diameter is ~180 km >1700 craters and basins 20 to >1000 km in diameter were produced David A. Kring/NAC Lunar Workshop/Feb 2007
Pre-Nectarian Basins Impact Basin Diameter (km) Age (Ga) Apollo 505 Grimaldi 430 Freundlick-Sharonov 600 Birkhoff 330 Planck 325 Schiller-Zucchius 325 Amundsen-Ganswindt 355 Lorentz 360 Smythii 840 Coulomb-Sarton 530 Keeler-Heaviside 780 Poincare 340 ? Ingenii 560 Lomonosov-Fleming 620 Nubium 690 Mutus-Vlacq 690 Tranquillitatis 800 Australe 880 Fecunditatis 990 Al-Khwarizmi/King 590 Pingre-Hausen 300 Werner-Airy 500 Balmer-Kapteyn 550 Flamsteed-Billy 570 Marginis 580 Insularum 600 Grissom-White 600 Tsiolkovskiy-Stark 700 South Pole-Aitken 2500 Procellarum 3200 David A. Kring/NAC Lunar Workshop/Feb 2007
Pre-Nectarian Basins Impact Basin Age (Ga) Diameter (km) Apollo 505 Grimaldi 430 Freundlick-Sharonov 600 Birkhoff 330 Planck 325 Schiller-Zucchius 325 Amundsen-Ganswindt 355 Lorentz 360 Smythii 840 Coulomb-Sarton 530 Keeler-Heaviside 780 Poincare 340 Ingenii 560 Lomonosov-Fleming 620 Nubium 690 Mutus-Vlacq 690 Tranquillitatis 800 Australe 880 Fecunditatis 990 Al-Khwarizmi/King 590 Pingre-Hausen 300 Werner-Airy 500 Balmer-Kapteyn 550 Flamsteed-Billy 570 Marginis 580 Insularum 600 Grissom-White 600 Tsiolkovskiy-Stark 700 Highest Priority South Pole-Aitken 2500 Procellarum 3200 David A. Kring/NAC Lunar Workshop/Feb 2007
Pre-Nectarian Basins Impact Basin Diameter (km) Age (Ga) Apollo 505 Grimaldi 430 Freundlick-Sharonov 600 Birkhoff 330 Planck 325 Schiller-Zucchius 325 Amundsen-Ganswindt 355 Lorentz 360 Smythii 840 Coulomb-Sarton 530 Keeler-Heaviside 780 Poincare 340 ? Ingenii 560 Lomonosov-Fleming 620 Nubium 690 Mutus-Vlacq 690 Tranquillitatis 800 Australe 880 Fecunditatis 990 Al-Khwarizmi/King 590 Pingre-Hausen 300 3 Werner-Airy 500 Balmer-Kapteyn 550 Flamsteed-Billy 570 Marginis 580 Insularum 600 2 Grissom-White 600 Tsiolkovskiy-Stark 700 1 South Pole-Aitken 2500 Procellarum 3200 David A. Kring/NAC Lunar Workshop/Feb 2007
Representative Eratosthenian Craters Impact Crater Diameter (km) Age (Ga) Lambert 30 Reiner 30 Archytas 32 Timocharis 34 Stearns 37 Manilius 39 Herschel 41 Rothmann 42 Plinius 43 ? Reinhold 43 Agrippa 44 Hainzel A 53 Maunder 55 Eratosthenes 58 Bullialdus 61 Hercules 69 Werner 70 Fabricius 78 Aristoteles 87 Theophilus 100 (rayed) Pythagoras 130 Langrenus 132 (rayed) Hausen 167 (largest young crater) David A. Kring/NAC Lunar Workshop/Feb 2007
How do we determine the impact flux? We collect impact melt breccias.
Impact Melt Breccias Terrestrial Analogues + Apollo Examples Kring/Space Sciences 2006 Lunar Exploration Initiative David A. Kring/NAC Lunar Workshop/Feb 2007
Copernicus Crater Lunar Observer II Kring/Space Sciences 2006 Lunar Exploration Initiative David A. Kring/NAC Lunar Workshop/Feb 2007
Sampling Lunar Impact Melt Lunar Observer V • Impact melts can be collected within lunar craters • Alternatively, they can be collected from debris ejected from crater (next slides) Kring/Space Sciences 2006 Lunar Exploration Initiative David A. Kring/NAC Lunar Workshop/Feb 2007
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