Presentation on theme: "Meteorites Fragments of the Solar System. Dedicated to Dr. Elbert King –First director of the Lunar Receiving Lab –Recovered a lot of Allende!! –Meteoriticist."— Presentation transcript:
Meteorites Fragments of the Solar System
Dedicated to Dr. Elbert King –First director of the Lunar Receiving Lab –Recovered a lot of Allende!! –Meteoriticist
Meteorites Meteoroids –small rocks orbiting in space Meteors –rocks entering the atmosphere and glowing –Most are the size of a grain of sand –Some are a lot bigger!!! Meteorites –Rocks from space that have hit the Earth
Thunderstone of Ensisheim 1492
Thunderstone of Ensisheim Whats left of it
What Holbrook supposedly looked like 1946
Famous painting of the Shikote-Alin meteorite on a USSR postage stamp.
Meteorites Irons iron + nickel Stoney Irons –Mesosiderites MES silicate + iron –Pallasites PAL iron + silicate (olivine) Stoney –Chondrites silicate + some iron (sometimes) Ordinary ChondritesH, L, LL Carbonaceous Chondrites C, CO, CV, CM, CK Others – Enstatite Chondrites E – Rumruti R –Achondrites HED – from Vesta SNC – from Mars ALUN – from the Moon
Irons Cape York – discovered by Peary from Greenland actually discovered by local Inuit
Witmanstatten Patterns Gibeon
Irons Hoba – 60 tons Campo del Cielo
Stony Irons Mesosiderites - MES Silicate based – with a lot of metal running through it. NWA1879
Stoney Irons Another mesosiderite -MES
Stoney Irons Mesosiderite Morristown
Stoney Iron Pallasites Iron based – with olivine crystals sprinkled through Thought to be from the core- mantle boundary of the parent asteroid
Stoney Iron Pallasite – lit from behind
Stoney - Chondrites Ordinary Chondrites –H (High Metal) – L (Low Metal) – LL (Very Low Metal) Inside (Brecciated) Outside (Crusted) Probably a L4-5 – this comes from NWA – Morocco
Chondrules / Chondrites
Stoney - Chondrites Carbonaceous chondrites –Residue from the formation of the Solar System – 4.5+ Billion Years old Allende – CV3.2 Murcheson – CM2
Stoney - Achondrites HED Howardite DAG 844 Meteorites from Asteroid 4 Vesta
Stoney - Achondrites HED Eucrite Millbillillie
Stoney - Achondrites HED Diogenite Johnstown
Stoney - Achondrites SNC Shergottite Zagami Meteorites from Mars
Stoney - Achondrites SNC Dhofar 019 DAG 476
Stoney - Achondrites ALUN DAG 400 Meteorites from the Moon
How do we know they are from Mars / the Moon / 4 Vesta?? Mars: Viking 1 and 2 had soil and atmosphere analyzers. The percentages of the elements and isotopes are the same as the SNC meteorites – and different from others! The Moon: Same story – except we have real moon rocks to compare them to Vesta: Spectroscopy of Vesta indicates it is made of HED materials, and no other asteroid is. Recent studies show a great crater on Vesta where some of these materials must have been ejected from.
How to Study Meteorites What does it look like (big picture) What does it look like (microscope) What elements are in it (chemistry and microprobe) What isotopic ratios are there (microprobe) Where did it come from (compare to asteroids and planets) How did it fall (distribution)
Meteorites / Meteorwrongs Meteorites are not hot when they hit the earth! Almost all meteorites are magnetic! Almost all meteorites have some visible metal (though sometimes only a little). Most meteorites are denser than local rocks. Meteorites dont have holes/bubbles in them. For real analysis you have to take it to an expert
How to Study Meteorites Thin Sections – The coolest way to look at meteorites is in thin section. Take a thin slice of the rock, glue it to a microscope slide and grind/polish it until it is 30 micrometers thick. You can then look at it under a petrographic microscope with crossed polarizing filters. The colors tell you the minerals!
Some chondrules in thin section
Eucrite thin section Looks a lot like Kilauea basalts!
Apollo 17 Basalt
Apollo 12 Basalt
Impact!!! When a Big rock hits – 50 meters or more – it can make a rather big hole in the ground!!!!
Sudbury + Lake Wanapitei
Disclaimer Aloha I put together these power points for use in my science classes. You may use them in your classes. Some images are public domain, some are used under the fair-use provisions of the copyright law, some are mine. Copyright is retained by the owners! Ted Brattstrom