^1,2S. Guénon,¹J. G. Ramírez,¹Ali C. Basaran,¹J. Wampler,³M. Thiemens,
⁴S. Taylor, ¹Ivan K. Schuller
¹Department of Physics and Center for Advanced Nanoscience, University of California San Diego, La Jolla CA 92093, USA
²CQ Center for Collective Quantum Phenomena and their Applications in LISA+, Physikalisches Institut, Eberhard-Karls-Universität Tübingen, Auf der Morgenstelle 14, D-72076, Tübingen, Germany
³Department of Chemistry and Biochemistry, University of California San Diego, La Jolla CA 92093, USA
⁴Cold Regions Research and Engineering Laboratory, Hanover, NH 03766-1290

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Reference
Guénon S, Ramírez JG, Basaran AC, Wampler J, Thiemens M, Taylor S, Schuller IK (2014) Search for Superconductivity in Micrometeorites. Scientific Reports 4
Link to Article [doi:10.1038/srep07333]

¹Herbert Palme, ^2,3Dominik C. Hezel, ⁴Denton S. Ebel
¹Forschungsinstitut und Naturmuseum Senckenberg, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany
²Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicherstrasse 55, Germany
³Natural History Museum, Department of Mineralogy, Cromwell Road, SW7 5BD, London, UK
⁴Department of Earth and Planetary Sciences, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA

One of the major unresolved problems in cosmochemistry is the origin of chondrules, once molten, spherical silicate droplets with diameters of 0.2 to 2 mm. Chondrules are an essential component of primitive meteorites and perhaps of all early solar system materials including the terrestrial planets. Numerous hypotheses have been proposed for their origin. Many carbonaceous chondrites are composed of about equal amounts of chondrules and fine-grained matrix. Recent data confirm that matrix in carbonaceous chondrites has high Si/Mg and Fe/Mg ratios when compared to bulk carbonaceous chondrites with solar abundance ratios. Chondrules have the opposite signature, low Si/Mg and Fe/Mg ratios. In some carbonaceous chondrites chondrules have low Al/Ti ratios, matrix has the opposite signature and the bulk is chondritic. It is shown in detail that these complementary relationships cannot have evolved on the parent asteroid(s) of carbonaceous chondrites. They reflect preaccretionary processes. Both chondrules and matrix must have formed from a single, solar-like reservoir. Consequences of complementarity for chondrule formation models are discussed. An independent origin and/or random mixing of chondrules and matrix can be excluded. Hence, complementarity is a strong constraint for all astrophysical–cosmochemical models of chondrule formation. Although chondrules and matrix formed from a single reservoir, the chondrule-matrix system was open to the addition of oxygen and other gaseous components.

Reference
Palme H, Hezel DC, Ebel DS (2014) The origin of chondrules: Constraints from matrix composition and matrix-chondrule complementarity. Earth and Planetary Science Letters (in Press)
Link to Article [doi:10.1016/j.epsl.2014.11.033]

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