Showing papers by "Henner Busemann published in 2014"

Fall, recovery, and characterization of the Novato L6 chondrite breccia

Abstract: The Novato L6 chondrite fragmental breccia fell in California on 17 October 2012, and was recovered after the Cameras for Allsky Meteor Surveillance (CAMS) project determined the meteor's trajectory between 95 and 45 km altitude. The final fragmentation at 33 1 km altitude was exceptionally well documented by digital photographs. The first sample was recovered before rain hit the area. First results from a consortium study of the meteorite's characterization, cosmogenic and radiogenic nuclides, origin and conditions of the fall are presented. Some meteorites did not retain fusion crust and show evidence of spallation. Before entry, the meteoroid was 35+/-5 cm in diameter (mass 80+/-35 kg) with a cosmic ray exposure age of 9+/-1 Ma, if it had a one-stage exposure history. However, based on the cosmogenic nuclide inventory, a two-stage exposure history is more likely, with lower shielding in the last few Ma. Thermoluminescence data suggest a collision event within the last approx. 0.1 Ma. Novato likely belonged to the class of shocked L chondrites that have a common shock age of 470 Ma, based on the U,Th-He age of 460+/-220 Ma. The measured orbits of Novato, Jesenice and Innisfree are consistent with a proposed origin of these shocked L chondrites in the Gefion asteroid family, but leave open the possibility that they came to us directly from the 5:2 mean motion resonance with Jupiter. Novato experienced a stronger compaction than did other L6 chondrites of shock-stage S4. Despite this, a freshly broken surface shows a wide range of organic compounds.

Fluid-induced organic synthesis in the solar nebula recorded in extraterrestrial dust from meteorites

Abstract: Isotopically anomalous carbonaceous grains in extraterrestrial samples represent the most pristine organics that were delivered to the early Earth. Here we report on gentle aberration-corrected scanning transmission electron microscopy investigations of eight 15N-rich or D-rich organic grains within two carbonaceous Renazzo-type (CR) chondrites and two interplanetary dust particles (IDPs) originating from comets. Organic matter in the IDP samples is less aromatic than that in the CR chondrites, and its functional group chemistry is mainly characterized by C–O bonding and aliphatic C. Organic grains in CR chondrites are associated with carbonates and elemental Ca, which originate either from aqueous fluids or possibly an indigenous organic source. One distinct grain from the CR chondrite NWA 852 exhibits a rim structure only visible in chemical maps. The outer part is nanoglobular in shape, highly aromatic, and enriched in anomalous nitrogen. Functional group chemistry of the inner part is similar to spectra from IDP organic grains and less aromatic with nitrogen below the detection limit. The boundary between these two areas is very sharp. The direct association of both IDP-like organic matter with dominant C–O bonding environments and nanoglobular organics with dominant aromatic and C–N functionality within one unique grain provides for the first time to our knowledge strong evidence for organic synthesis in the early solar system activated by an anomalous nitrogen-containing parent body fluid.

Petrography, stable isotope compositions, microRaman spectroscopy, and presolar components of Roberts Massif 04133: A reduced CV3 carbonaceous chondrite.

Abstract: Here, we report the mineralogy, petrography, C-N-O-stable isotope compositions, degree of disorder of organic matter, and abundances of presolar components of the chondrite Roberts Massif (RBT) 04133 using a coordinated, multitechnique approach. The results of this study are inconsistent with its initial classification as a Renazzo-like carbonaceous chondrite, and strongly support RBT 04133 being a brecciated, reduced petrologic type >3.3 Vigarano-like carbonaceous (CV) chondrite. RBT 04133 shows no evidence for aqueous alteration. However, it is mildly thermally altered (up to approximately 440 °C); which is apparent in its whole-rock C and N isotopic compositions, the degree of disorder of C in insoluble organic matter, low presolar grain abundances, minor element compositions of Fe,Ni metal, chromite compositions and morphologies, and the presence of unequilibrated silicates. Sulfides within type I chondrules from RBT 04133 appear to be pre-accretionary (i.e., did not form via aqueous alteration), providing further evidence that some sulfide minerals formed prior to accretion of the CV chondrite parent body. The thin section studied contains two reduced CV3 lithologies, one of which appears to be more thermally metamorphosed, indicating that RBT 04133, like several other CV chondrites, is a breccia and thus experienced impact processing. Linear foliation of chondrules was not observed implying that RBT 04133 did not experience high velocity impacts that could lead to extensive thermal metamorphism. Presolar silicates are still present in RBT 04133, although presolar SiC grain abundances are very low, indicating that the progressive destruction or modification of presolar SiC grains begins before presolar silicate grains are completely unidentifiable.

A Precise Cosmic-Ray Exposure Age for an Olivine Grain from the Surface of Near-Earth Asteroid (25143) Itokawa

Abstract: NEAR-EARTH ASTEROID (25143) ITOKAWA. M. M. M. Meier, C. Alwmark, S. Bajt, U. Bottger, H. Busemann, W. Fujiya, J. Gilmour, U. Heitmann, P. Hoppe, H.-W. Hubers, F. Marone, U. Ott, S. Pavlov, U. Schade, N. Spring, M. Stampanoni, I. Weber. Dept. of Geology, Lund University, Solvegatan 12, 22362 Lund, Sweden (matthias.meier@geol.lu.se), Photon Sci./DESY, Hamburg, Germany, DLR, Planet. Res. Inst., Berlin, Germany, SEAES, Univ. of Manchester, UK, Max Planck Inst. f. Chemistry, Mainz, Germany, Inst. f. Planetologie, WWU Munster, Germany, Swiss Light Source, Paul Scherrer Inst., Villigen, Switzerland, Helmholtz-Zentr., Berlin, Germany, Inst. for Biomed. Eng., Univ. & ETH Zurich, Switzerland.

Characteristics of djerfisherite from fluid-rich, metasomatized alkaline intrusive environments and anhydrous enstatite chondrites and achondrites

Abstract: Djerfisherite is a K-Cl-bearing sulfide that is present in both ultra-reduced extraterrestrial enstatite meteorites (enstatite chondrites or achondrites) and reduced terrestrial alkaline intrusions, kimberlites, ore deposits, and skarns. Major element chemistry of two terrestrial occurrences of djerfisherite (from the Ilimaussaq and Khibina alkaline igneous suites) and three extraterrestrial examples of djerfisherite have been determined and combined with petrographic characterization and element mapping to unravel three discrete modes of djerfisherite formation. High Fe/Cu is characteristic of extraterrestrial djerfisherite and low Fe/Cu is typical of terrestrial djerfisherite. Ilimaussaq djerfisherite, which has high-Fe contents (~55 wt%) is the exception. Low Ni contents are typical of terrestrial djerfisherite due to preferential incorporation of Fe and/or Cu over Ni, but Ni contents of up to 2.2 wt% are measured in extraterrestrial djerfisherite. Extensive interchange between K and Na is evident in extraterrestrial samples, though Na is limited (

Xenon in Antarctic Micrometeorites (AMMs) and Interplanetary Dust Particles (IDPs)

Abstract: Introduction: IDPs collected by NASA airplanes in the upper atmosphere [1] and Antarctic Micrometeorites (AMMs) [2-4] extracted from ice and snow by melting and filtering, likely sample a similar mixture of reservoirs, including asteroids and comets [5]. The sample types differ mainly in collection method and size of the particles; IDPs are typically <50 μm after impacting the collector (cluster IDPs are as large as 500 μm before impact), AMMs are typically 20-500 μm. Micrometeorites are often recovered partially melted or as fully melted spherules, therefore often having no detectable, or a contaminated noble gas content, however ~35% of those recovered from Dome-C in Antarctica have no evidence of heating [5] and are therefor promising for noble gas analyses. AMMs have been analysed for their noble gas content e.g. by [6-10], revealing that samples either have a component resembling primordial Q-Xe, fractionated air from atmospheric entry, or addition of solar components [6]. The small size of IDPs and AMMs is still a problem for measuring the heavy noble gases, with large analytical errors reported. RELAX (Refrigerator Enhanced Laser Analyser for Xenon) at the University of Manchester [11] has the potential to detect Xe down to 500 atoms. Previous experiments failed to detect significant Xe in typical chondritic porous IDPs [12, 13], however large concentrations of trapped Xe were reported in four combined metal-rich non-chonditic IDPs, although the Xe isotopic composition could not be distinguished [14]. Here we present initial results from analyses of small (20-145 μm) AMMs, with the hope of learning more of the origin and distribution of their noble gases and parent bodies, as well as finetuning the experiments for even smaller (5-25 μm) IDP samples; the results of which are due to be presented at the conference. Sample Set: 20 AMMs (Table 1) were initially characterised for texture and composition in Orsay. They include 10 from the Cap-Prudhomme collection [15] and 10 from Dome-C of the Concordia collection [16]. There are a mixture of textures; Crystal (Xtal), Fine-grained Scoriaceous (FgSc) and Fine-grained Compact (FgC), as defined by [17] (Table 1). Some samples are fragments of AMMs also distributed to [9], and therefore a more complete noble gas catalogue can be eventually compiled for these samples. 26 IDPs from several collectors have been analysed for H, C and N isotopes and C-Raman characteristics [18]. Experimental: Samples were prepared in a clean room and placed in individual holes in a molybdenum mount, then loaded into the sample holder of the RELAX mass spectrometer [11] (IDPs will remain pressed into the gold foils used for NanoSIMS analysis). AMM samples were heated in 1 minute intervals with a Nd:YAG until all gas had been extracted. Data were calibrated against air measured before and after each sample, and a regular blank measurement was substracted. Typical blanks amount to ~1700? atoms 132Xe and contribute 1-10 % of the Xe in the most gas-rich steps for each AMM but much more in gaspoor extractions. To roughly estimate the mass, each AMM was approximated to a spheroid with a diameter averaged from the longest axis through each AMM and the centered axis perpendicular to it. The density was assumed to be 2.5 g/cm. Typical mass errors are 30–50 %.

Preface: Evolution of refractory grains, volatiles, and organic molecules from the interstellar medium to the early solar system

Abstract: Primitive extraterrestrial materials record the early evolution of the solar system that predated planet formation. They also preserve the interstellar heritage from prior to the Sun’s birth in the form of presolar grains and potentially as isotopic signatures of light elements in organic matter and specific molecules. It is one of the key issues in cosmochemistry to link the birth and evolution of the solar system to the evolution of the interstellar medium (ISM) and the Galaxy. To address this issue, an interdisciplinary approach linking analysis of extraterrestrial materials including samples returned by spacecraft, laboratory experiments, astronomical observations, and theo

Xenon Release by the In-Vacuum Etching of Aerogel: Implications for the Study of Noble Gases in Comet Wild 2 Stardust

Abstract: Xenon detection in comet Wild 2 stardust is hampered by the large adsorption of Xe on aerogel. In-vacuum etching presented here may enable the stepwise separation of terrestrial Xe, cometary Xe trapped in melted aerogel and Xe in cometary silicates.