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We review the radiometric ages of the 16 currently known Martian meteorites, classified as 11 shergottites (8 basaltic and 3 lherzolitic), 3 nakhlites (clinopyroxenites), Chassigny (a dunite), and the orthopyroxenite ALH84001. The basaltic shergottites represent surface lava flows, the others magmas that solidified at depth. Shock effects correlate with(More)
  • F. BEGEMANN, K. R. LUDWIG, +7 authors R. J. WALKER
  • 2000
The accuracy of radioisotopic ages is, at present, limited by the accuracy of radioactive decay constants. A literature survey reveals that decay constants used in geoand cosmochronology usually are assigned uncertainties of ca. 1% but that there are very much larger unaccounted discrepancies between decay constants reported by different “counting groups”(More)
Introduction: Nakhlites are olivine-bearing clinopyroxenites with cumulate textures, and probably came from Mars [e.g., 1]. A total of seven nakhlites have been identified so far. Unlike other martian meteorites (e.g., shergottites), nakhlites have been only moderately shocked and their original igneous textures are still well-preserved. Also, these(More)
UCN-01, 7-hydroxystaurosporine, is an antagonist of protein kinase C, as well as causing cell cycle arrest. We developed and validated an HPLC assay method for the quantitation of UCN-01. Plasma and saliva standard curves were prepared at concentrations ranging from 0.2 to 20.0 microgram/mL and 4.0 to 200.0 ng/mL, respectively. The sample preparation(More)
Introduction: RBT 04262 and LAR 06319 are two Martian meteorites recently discovered in Antarctica. Both contain abundant olivines, and were classified as olivinephyric shergottites [1]. A detailed petrographic study of RBT 04262 by [2] suggested it should be reclassified as a lherzolitic shergottite. However, the moderately LREE-depleted REE distribution(More)
K. Misawa, C.-Y. Shih, H. Wiesmann and L. E. Nyquist. Antarctic Meteorite Research Center, National Institute of Polar Research, 1-9-10 Kaga, Itabashi, Tokyo 173-8515, Japan (misawa@nipr.ac.jp), Mail Code C23, Lockheed-Martin Space Operations, 2400 NASA Road 1, Houston, TX 77058, U.S.A. (chi-yu.shih1@jsc.nasa.gov), Mail Code SR, NASA Johnson Space Center,(More)
Introduction: The largest group of iron meteorites , IAB, is distinguished by the presence of diverse silicate inclusions. In principle, Rb-Sr and Sm-Nd ra-diometric dating of these silicate inclusions by internal isochron techniques can determine both the times of melting and parent/daughter ratios in the precursor materials via initial
Introduction: The coupled Sm-Nd systematics of lunar samples has been extensively studied for estimating the timescale of lunar differentiation [1-3]. The published datasets yield consistent ages for Nd isotopic closure within the lunar mantle of ~200 Myr after CAI formation. Although this time constraint is consistent with estimates derived from Hf-W(More)
Introduction: Although chondrule formation by melting of precursor materials has been favored, the model has a fundamental disadvantage that the diversities of bulk compositions are not well explained (e.g. [1]). Key question: A precise and comprehensive study of chon-drule compositions for primitive ordinary chondrites revealed the refractory element(More)