¹Rainer Bartoschewitz et al. (>10)*
Chemie der Erde – Geochemistry (in Press) Link to Article [http://dx.doi.org/10.1016/j.chemer.2016.10.004]
¹Bartoschewitz Meteorite Laboratory, Weiland 37, D-38518 Gifhorn, Germany
*Find the extensive, full author and affiliation list on the publishers website
Copyright Elsevier

On April 23rd 2013 at 2:07 a.m., a 1.3 kg meteorite fell in the Braunschweig suburb Melverode (52° 13′ 32.19″ N. 10° 31′ 11.60″ E). Its estimated velocity was 250 km/h and it formed an impact pit in the concrete fall site with a diameter of 7 cm and a depth of 3 cm. Radial dust striae are present around the impact pit. As a result of the impact, the meteorite disintegrated into several hundred fragments with masses up to 214 g. The meteorite is a typical L6 chondrite, moderately shocked (S4) – but with a remarkably high porosity (up to 20 vol%). The meteorite was ejected from its parent body as an object with a radius of about 10–15 cm (15–50 kg). The U,Th-He gas retention age of ∼550 Ma overlaps with the main impact event on the L-chondrite parent body ∼470 Ma ago that is recorded by many shocked L chondrites. The preferred cosmic-ray exposure age derived from production of radionuclides and noble gas isotopes is (6.0 ± 1.3) Ma.

¹Richard C. Greenwood, ²Thomas H. Burbine, ¹Martin F. Miller, ¹Ian. A. Franchi
Chemie der Erde – Geochemistry (in Press) Link to Article [http://dx.doi.org/10.1016/j.chemer.2016.09.005]
¹Planetary and Space Sciences, School of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA, United Kingdom
²Astronomy Department, Mount Holyoke College, South Hadley, MA 01075, USA
Copyright Elsevier

A number of distinct methodologies are available for determining the oxygen isotope composition of minerals and rocks, these include laser-assisted fluorination, secondary ion mass spectrometry (SIMS) and UV laser ablation. In this review we focus on laser-assisted fluorination, which currently achieves the highest levels of precision available for oxygen isotope analysis. In particular, we examine how results using this method have furthered our understanding of early-formed differentiated meteorites. Due to its rapid reaction times and low blank levels, laser-assisted fluorination has now largely superseded the conventional externally-heated Ni “bomb” technique for bulk analysis. Unlike UV laser ablation and SIMS analysis, laser-assisted fluorination is not capable of focused spot analysis. While laser fluorination is now a mature technology, further analytical improvements are possible via refinements to the construction of sample chambers, clean-up lines and the use of ultra-high resolution mass spectrometers.

High-precision oxygen isotope analysis has proved to be a particularly powerful technique for investigating the formation and evolution of early-formed differentiated asteroids and has provided unique insights into the interrelationships between various groups of achondrites. A clear example of this is seen in samples that lie close to the terrestrial fractionation line (TFL). Based on the data from conventional oxygen isotope analysis, it was suggested that the main-group pallasites, the howardite eucrite diogenite suite (HEDs) and mesosiderites could all be derived from a single common parent body. However, high precision analysis demonstrates that main-group pallasites have a Δ17O composition that is fully resolvable from that of the HEDs and mesosiderites, indicating the involvement of at least two parent bodies. The range of Δ17O values exhibited by an achondrite group provides a useful means of assessing the extent to which their parent body underwent melting and isotopic homogenization. Oxygen isotope analysis can also highlight relationships between ungrouped achondrites and the more well-populated groups. A clear example of this is the proposed link between the evolved GRA 06128/9 meteorites and the brachinites.

The evidence from oxygen isotopes, in conjunction with that from other techniques, indicates that we have samples from approximately 110 asteroidal parent bodies (∼60 irons, ∼35 achondrites and stony-iron, and  ∼15 chondrites) in our global meteorite collection. However, compared to the likely size of the original protoplanetary asteroid population, this is an extremely low value. In addition, almost all of the differentiated samples (achondrites, stony-iron and irons) are derived from parent bodies that were highly disrupted early in their evolution.

High-precision oxygen isotope analysis of achondrites provides some important insights into the origin of mass-independent variation in the early Solar System. In particular, the evidence from various primitive achondrite groups indicates that both the slope 1 (Y&R) and CCAM lines are of primordial significance. Δ17O differences between water ice and silicate-rich solids were probably the initial source of the slope 1 anomaly. These phases most likely acquired their isotopic composition as a result of UV photo-dissociation of CO that took place either in the early solar nebula or precursor giant molecular cloud. Such small-scale isotopic heterogeneities were propagated into larger-sized bodies, such as asteroids and planets, as a result of early Solar System processes, including dehydration, aqueous alteration, melting and collisional interactions.

There is increasing evidence that chondritic parent bodies accreted relatively late compared to achondritic asteroids. This may account for the fact that apart from a few notable exceptions’ such as the aubrite-enstatite chondrite association, known chondrite groups could not have been the parents to the main achondrite groups.

^1,2,3Stefan T.M. Peters, ^1,2Carsten Münker, ^1,2Markus Pfeifer, ^1,2Bo-Magnus Elfers, ^1,2Peter Sprung
Earth and Planetary Science Letters (in Press) Link to Article [http://dx.doi.org/10.1016/j.epsl.2016.11.009]
¹Institut für Geologie und Mineralogie, Universität zu Köln, Zülpicherstr. 49b, 50674 Cologne, Germany
²Steinmann-Institut, Poppelsdorfer Schloss, 53115 Bonn, Germany
³Geowissenschaftliches Zentrum der Georg-August-Universität Göttingen, Department of Isotope Geology, Goldschmidtstrasse 1, 37077 Göttingen, Germany
Copyright Elsevier

Some nuclides that were produced in supernovae are heterogeneously distributed between different meteoritic materials. In some cases these heterogeneities have been interpreted as the result of interaction between ejecta from a nearby supernova and the nascent solar system. Particularly in the case of the oldest objects that formed in the solar system – Ca–Al rich inclusions (CAIs) – this view is confirm the hypothesis that a nearby supernova event facilitated or even triggered solar system formation. We present Hf isotope data for bulk meteorites, terrestrial materials and CAIs, for the first time including the low-abundance isotope 174Hf (∼0.16%). This rare isotope was likely produced during explosive O/Ne shell burning in massive stars (i.e., the classical “p-process”), and therefore its abundance potentially provides a sensitive tracer for putative heterogeneities within the solar system that were introduced by supernova ejecta. For CAIs and one LL chondrite, also complementary W isotope data are reported for the same sample cuts. Once corrected for small neutron capture effects, different chondrite groups, eucrites, a silicate inclusion of a IAB iron meteorite, and terrestrial materials display homogeneous Hf isotope compositions including 174Hf. Hafnium-174 was thus uniformly distributed in the inner solar system when planetesimals formed at the

¹A. A. Garde, ²Martin B. Klausen
Journal of the Geological Society 173, 954-965 Link to Article [doi: 10.1144/jgs2015-147]
¹Geological Survey of Denmark and Greenland, Øster Voldgade 10, 1350 Copenhagen K, Denmark
²Department of Earth Sciences, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa

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¹Grethe Hystad, ²Robert T. Downs, ³Robert M. Hazen, ²Joshua J. Golden
Mathematical Geosciences (in Press) Link to Article [doi:10.1007/s11004-016-9661-y]
¹Mathematics, Statistics, and Computer SciencePurdue University Northwest Hammond USA
²Department of Geosciences University of Arizona Tucson USA
³Geophysical Laboratory Carnegie Institution for Science Washington USA

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¹Rudra Chatterjee, ¹John C. Lassiter
Chemical Geology 442, 11-22 Link to Article [http://dx.doi.org/10.1016/j.chemgeo.2016.08.033]
¹Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, 1 University Station C1160, Austin, TX -78712-0254, United States

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^1,2Hossein Izadi, ^3,4Javad Sadri, ⁵Mahdokht Bayati
Computers and Geoscience 99, 37–49 Link to Article [http://dx.doi.org/10.1016/j.cageo.2016.10.010]
¹Department of Petroleum Exploration Engineering, Faculty of Mining Engineering, University College of Engineering, University of Tehran, Tehran, Iran
²Technical Advisory, National Iranian South Oilfields Company (NISOC), Ahvaz, Iran
³Department of Computer Science & Software Engineering, Faculty of Engineering and Computer Science, Concordia University, Montreal, Quebec, Canada H3G 1M8
⁴Department of Computer Engineering, Faculty of Electrical and Computer Engineering, University of Birjand, Birjand, Iran
⁵Institute of Geophysics, University of Tehran, Tehran, Iran

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¹Agnes Kontny, ¹Lea Grothaus
Studia Geophysica et Geodaetica (In Press) Link to Article [doi:10.1007/s11200-016-0819-3]
¹Institute of Applied Geosciences, Division of Structural Geology Karlsruhe Institute of Technology Karlsruhe Germany

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¹A. Espartero, ²José M. Madiedo
Earth, Moon and Planets 118, 81-89 Link to Article [doi:10.1007/s11038-016-9491-4]
¹Facultad de Ciencias Experimentales, Universidad de Huelva, Huelva, Spain
²Departamento de Física Atómica, Molecular y Nuclear. Facultad de Física, Universidad de Sevilla, Seville, Spain

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¹A. Kereszturi, ²I. Gyollai, ³Zs. Kereszty, ⁴K. Kiss, ²M. Szabó, ^4,6Z. Szalai, ^4,6M. Ringer, ⁵M. Veres
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 173, 637–646 Link to Article [http://dx.doi.org/10.1016/j.saa.2016.10.012]
¹Research Centre for Astronomy and Earth Sciences, Konkoly Thege Miklos Astronomical Institute, H-1121 Budapest, Konkoly Thege Miklós út 15-17, Hungary
²Research Centre for Astronomy and Earth Sciences, Institute for Geological and Geochemical Research, H-1112 Budapest, Budaörsi út 45, Hungary
³International Meteorite Collectors Association (IMCA#6251), H 9024 Győr, Lahner u 1, Hungary
⁴Geographical Institute, H-1112 Budapest, Budaörsi út 45, Hungary
⁵Wigner Research Centre for Physics, H-1121 Budapest, Thege Miklós út 29-33, Hungary
⁶ELTE Department of Environmental and Landscape Geography, Hungary

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