Dimitri A. Papanastassiou

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Visitor in Geochemistry

Research Interests: Formation and evolution of meteorites and planets; establishment of a time sequence of condensation and isolation of bodies from the solar nebula; study of correlated isotopic anomalies in meteorites and their connection with specific nucleosynthetic processes. The associated experimental techniques involve high precision mass spectrometry and ultra-clean sample processing and chemical separations. The research has centered on the creation of a fine resolution time scale for meteorites, the establishment of a lunar chronology, and the interpretation of these results in terms of a model for the accretion and the subsequent evolution of the moon as a planet. Major discoveries have included the identification of ²⁶Mg excesses and their correlation with short-lived, live ²⁶Al in the solar system, and the identification of correlated, general isotopic anomalies for many elements in early solar system condensates. The discoveries have provided strong evidence for the introduction of extremely short-lived nuclides in the early solar system and for the preservation of distinct, exotic nucleosynthetic products at the time of solar system formation. Research interests have addressed kinetic and equilibrium, mass dependent isotope fractionation effects on the Earth, on the surface of the Moon, in refractory condensates in the early solar system, and in systems of biological interest. The development of novel, sensitive analytical techniques has been critical. This has included the acquisition and development a high abundance sensitivity mass spectrometer (NSF, Instrumentation and Facilities, D. A. Papanastassiou, PI, Caltech). The instrument was redesigned to yield an abundance sensitivity of 3 x 10^-11 amu^-1, in the U-Th mass region, which approaches the levels for accelerator mass spectrometry. This instrumentation has been applied to U-Th series disequilibrium studies. Techniques for the thermal ionization of platinum group elements have been successfully developed (as negative oxide ions) and have resulted in improvements in sensitivity of factors of ~10⁴, and in key applications for the chronology of meteorites, terrestrial samples and the study of element transport in the environment. The techniques are being applied intensively to the Re-Os system in meteorites and lunar samples and to the study of platinum group elements (Ru, Mo, Re, Os, Ir). Starting in 1999, after appointment as the Mars Sample Handling Scientist, at the Jet Propulsion Laboratory, in anticipation of the 2003-2005 Mars Sample Return (MSR) missions, I designed, constructed, and operate new analytical facilities (sample preparation, analytical chemical separations, and mass spectrometry), with state-of-the-art instrumentation and capabilities. While the MSR missions have been postponed, these facilities are used for research on extraterrestrial materials, including for micro-samples from several on-going and planned missions. The most recent work, over the last two years has been development of thermal ionization techniques for isotopic analyses of Ni, once we tried and then decided that the universal use of ICP-MS by others is fraught with danger. Our recently published paper shows that reported effects by ICP-MS, by two other labs, in sulfides from iron meteorites are artifacts. In the period 2004-2005, I participated, as the Project Scientist, in a proposed mission to return samples from the South Pole-Aitken Basin, on the far side of the Moon, as highly recommended, for a New Frontiers mission, by the NRC Decadal Survey (2003), on which I also served. The proposal was selected for a Phase A, more extensive study, but was not the final selection. We have successfully resubmitted an updated South Pole-Aitken Basin proposal in the current New Frontiers competition and been selected and are currently working on a one year-long Phase A Concept Study for the mission. Final selection is expected in mid-2011.

Version July 2010

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LIST OF PUBLICATIONS

REFEREED PAPERS

J.H. Chen and D.A. Papanastassiou (2013) Mo isotope evidence for isotope heterogeneity in the early solar system. Geochim. Cosmochim. Acta (Submitted May 2013). [PDF]

C. Holmden, D. A. Papanastassiou, P. Blanchon, and S. Evans (2012) δ^44/40Ca variability in shallow water carbonates and the impact of submarine groundwater discharge on Ca-cycling in marine environments. Beochim. Cosmochim. Acta 83, 179-194. [PDF]

N. Dauphas, L. Remusat, J.H. Chen, M. Roskosz, D.A. Papanastassious, J. Stodolna, Y. Guan, C. Ma, and J.M. Eiler (2010) Neutron-rich chromium isotope anomalies in supernova nanoparticles, Ap. J. 720, 1577-1591. [PDF]

J. H. Chen, D. A. Papanastassiou, and G. J. Wasserburg (2010) Evidence for endemic Ru isotope anomalies in the early solar system and their preservation in planetary differentiates. Geochim. Cosmochim. Acta 74, 3851-3862. [PDF]

G. Caro, D.A. Papanastassiou, and G.J. Wasserburg (2010) ⁴⁰K-⁴⁰Ca isotopic constraints on the oceanic calcium cycle. Earth Planet. Sci. Lett. 296, 124-132. [PDF]

J. H. Chen, D. A. Papanastassiou, and G. J. Wasserburg (2009) A search for nickel isotopic anomalies in iron meteorites and chondrites. Geochim. Cosmochim. Acta 73, 1461-1471. [PDF]

J. H. Chen, D. A. Papanastassiou, and G. J. Wasserburg (2010) Evidence for endemic Mo isotope anomalies in the early solar system. [PDF]

D. W. Beaty, C. C. Allen, D. S. Bass, K. L. Buxbaum, J. K. Campbell, D. J. Lindstrom, S. L. Miller, and D. A. Papanastassiou (2009) Planning considerations for a Mars sample receiving facility. Astrobiology 9, 745-758.

M. E. Zolensky, et al. (incl. D. A. Papanastassiou) (2006) Mineralogy and petrology of comet 81P/Wild 2 nucleus samples. Science 314, 1735-1739.

D. Brownlee, et al. (incl. D. A. Papanastassiou) (2006) Comet 81P/Wild 2 under a microscope. Science 314, 1711-1716.

S. A. Sandford, et al. (incl. D. A. Papanastassiou) (2006) Organics captured from comet 81P/Wild 2 by the Stardust spacecraft. Science 314, 1720-1724.

K. D. McKeegan, et al. (incl. D. A. Papanastassiou) (2006) Isotopic compositions of cometary matter returned by Stardust. Science 314, 1724-1728.

G. J. Flynn, et al. (incl. D. A. Papanastassiou) (2006) Elemental compositions of comet 81P/Wild 2 samples collected by Stardust. Science 314, 1731-1735.

S. Liu, D. A. Papanastassiou, H. H. Ngo, B. P. Glass (2006) Sr and Nd analysis of upper Eocene spherules and their implications for target rocks. Meteor. Planet. Sci. 41, 705-714.

P. T. Doran, S. M. Clifford, S. L. Forman, L. E. Nyquist, D. A. Papanastassiou, B. W. Stewart (and nine authors) (2004) Mars chronology: assessing techniques for quantifying surficial processes. Earth Science Rev. 67, 313-337.

D. Lemarchand, G. J. Wasserburg, and D. A. Papanastassiou (2004) Rate-controlled calcium isotope fractionation in synthetic calcite. Geochim. Cosmochim. Acta 68, 4665-4678.

J. H. Chen, D. A. Papanastassiou, and G. J. Wasserburg (2002) Re-Os and Pd-Ag Systematics in Group IIIAB iron meteorites and in pallasites. Geochim. Cosmochim Acta 66, 3793-3810.

J. Whitehead, J. G. Spray, R. A. F. Grieve, D. A. Papanastassiou, H. H. Ngo, and G. J. Wasserburg (2000) Tracing the source of 36-million-year-old impact ejecta in marine sediments to the Popigai impact crater. Earth Planet. Sci. Lett. 181, 473-487.

P. T. Doran, S. L. Forman, N. C. Sturchio, S. M. Clifford, and D. A. Papanastassiou (2000) Measuring Geologic Time on Mars, Eos, Trans. Amer. Geophys. Union, 81. (Workshop Report).

J. H. Chen, D. A. Papanastassiou, and G. J. Wasserburg (1999) Re-Os systematics in chondrites and the fractionation of the platinum group elements in the early solar system. Geochim. Cosmochim. Acta 62, 3379-3392.

J. J. Shen, D. A. Papanastassiou, and G. J. Wasserburg (1998) Re-Os systematics in pallasites and mesosiderites. Geochim. Cosmochim. Acta 62, 2715-2723.

M. Roy-Barman, G. J. Wasserburg, D. A. Papanastassiou, and M. Chaussidon (1998) Osmium isotopic compositions and Re-Os concentrations in sulfide globules from basaltic glasses. Earth Planet. Sci. Lett. 154, 331-347.

A. D. Anbar, D. A. Papanastassiou, and G. J. Wasserburg (1997) The determination of iridium in natural waters by clean chemical pre-concentration and negative thermal ionization mass spectrometry. Anal. Chem. 69, 2444-2450.

C. Holmden, D. A. Papanastassiou, and G. J. Wasserburg (1997) Negative thermal ionization mass spectrometry of oxygen in phosphates. Geochim. Cosmochim. Acta 61, 2253-2263.

M. Sharma, D. A. Papanastassiou, and G. J. Wasserburg (1997) The concentration and isotopic composition of osmium in the oceans. Geochim. Cosmochim. Acta 61, 3287-3299.

B. W. Stewart, D. A. Papanastassiou, and G. J. Wasserburg (1996) Sm-Nd systematics of a silicate inclusion in the Caddo IAB iron meteorite. Earth Planet. Sci. Lett. 143, 1-12.

D. W. Peate, J. H. Chen, G. J. Wasserburg,, D. A. Papanastassiou, and J. W. Geissman (1996) ²³⁸U-²³⁰U dating of a geomagnetic excursion in Quaternary basalts of the Albuquerque Volcanic Field, NM (USA). Geophys. Res. Lett. 23, 2271-2274.

A. D. Anbar, G. J. Wasserburg, D. A. Papanastassiou, and P. S. Andersson (1996) Iridium in natural waters. Science 273, 1524-1528.

M. Sharma, D. A. Papanastassiou, G. J. Wasserburg, and R. F. Dymek (1996) The issue of terrestrial ¹⁴⁶Sm. Geochim. Cosmochim. Acta 60, 2037-2047.

M. Sharma, D. A. Papanastassiou, G. J. Wasserburg, and R. F. Dymek (1996) The issue of terrestrial ¹⁴⁶Sm, A Reply to the Comment by S. B. Jacobsen and C. L. Harper, Jr. Geochim. Cosmochim. Acta 60, 3751-3754.

J. J. Shen, D. A. Papanastassiou, and G. J. Wasserburg (1996) Precise Re-Os determinations and systematics on iron meteorites. Geochim. Cosmochim. Acta 60, 2887-2900.

M. Sharma, G. J. Wasserburg, D. A. Papanastassiou, J. E. Quick, E. V. Sharkov, and E. E. Lazko (1995) High ¹⁴³Nd/¹⁴⁴Nd in extremely depleted mantle rocks. Earth Planet.Sci. Lett. 125, 101-114.

B. W. Stewart, D. A. Papanastassiou, and G. J. Wasserburg (1994) Sm-Nd and Rb-Sr chronology and petrogenesis of mesosiderites. Geochim. Cosmochim. Acta 58, 3487-3509.

J. D. Blum, D. A. Papanastassiou, C. Koeberl, and G. J. Wasserburg (1992) Nd and Sr isotopic study of Australasian tektites: New constraints on the provenance and age of target materials. Geochim. Cosmochim. Acta 56, 483-492.

A. Prinzhofer, D. A. Papanastassiou, and G. J. Wasserburg (1992) Samarium-neodymium evolution of meteorites. Geochim. Cosmochim. Acta 56, 797-815.

A. D. Anbar, R. A. Creaser, D. A. Papanastassiou, and G. J. Wasserburg (1992) Rhenium in seawater: confirmation of generally conservative behavior. Geochim. Cosmochim. Acta 56, 4099-4103.

R. A. Creaser, D. A. Papanastassiou, and G. J. Wasserburg (1991) Negative thermal ion mass spectrometry of Os, Re, and Ir. Geochim. Cosmochim. Acta 55, 397-401.

J. Völkening and D. A. Papanastassiou (1990) Zinc isotope anomalies. Astrophys. J. (Letters) 358, L29-L32.

J. Völkening and D. A. Papanastassiou (1989) Iron isotope anomalies. Astrophys. J. (Letters) 347, L43-L46.

O. Stecher, H. H. Ngo, D. A. Papanastassiou, and G. J. Wasserburg (1989) Nd and Sr isotopic evidence for the origin of tektite material from DSDP site 612 off the New Jersey coast. Meteoritics 24, 89-98.

A. Prinzhofer, D. A. Papanastassiou, and G. J. Wasserburg (1989) The presence of ¹⁴⁶Sm in the early solar system and implications for its nucleosynthesis. Astrophys. J. (Letters) 344, L81-L84.

D. A. Papanastassiou and C. A. Brigham (1989) The identification of meteorite inclusions with isotope anomalies. Astrophys. J. (Letters) 338, L37-L40.

J. Bally, A. Boss, D. A. Papanastassiou, S. Sanford, and A. Sargent (1988) Star formation and the solar system. In Galactic and Extragalactic Star Formation, ed. R. E. Pudritz and M. Fich, Kluwer Academic Publishers, pp. 311-327.

D. A. Papanastassiou (1986) Correlated isotopic effects near the Fe abundance peak. In Advances in Nuclear Astrophysics, ed. E. Vangioniâ€'Flam, J. Audouze, M. Cassé, J. P. Chièze and J. T. T. Van, Éditions Frontières, pp. 449â€'459.

D. A. Papanastassiou (1986) Chromium isotopic anomalies in the Allende meteorite. Astrophys. J. (Letters) 308, L27-L30.

D. A. Papanastassiou (1985) Short-lived nuclides in the early solar system and general isotopic anomalies in meteorites. In Isotopic Ratios in the solar System, ed. D. Gautier, Centre National d' Études Spatiales (CNES), Cépaduesâ€'Editions, Toulouse, France, pp. 77-88.

D. A. Papanastassiou (1985) Survival and evolution: Deciphering the early solar nebula continues. Geotimes 30, 10-11.

F. R. Niederer, D. A. Papanastassiou, and G. J. Wasserburg (1985) Absolute isotopic abundances of Ti in meteorites. Geochim. Cosmochim. Acta 49, 835-851.

F. R. Niederer and D. A. Papanastassiou (1984) Ca isotopes in refractory inclusions. Geochim. Cosmochim. Acta 48, 1279-l293.

D. A. Papanastassiou, G. J. Wasserburg, and D. E. Brownlee (1983) Chemical and isotopic study of extraterrestrial particles collected from the ocean floor. Earth Planet. Sci. Lett. 64, 341-355.

G. J. Wasserburg and D. A. Papanastassiou (1982) Some shortâ€'lived nuclides in the early solar system: a connection with the placental ISM. In Essays in Nuclear Astrophysics, ed. C. A. Barnes, D. D. Clayton and D. N. Schramm, Cambridge Univ. Press, pp. 77-140.

F. R. Niederer, D. A. Papanastassiou, and G. J. Wasserburg (1981) The isotopic composition of titanium in the Allende and Leoville meteorites. Geochim. Cosmochim. Acta 45, 1017-1031.

D. A. Papanastassiou and G. J. Wasserburg (1981) Microchrons: the ⁸⁷Rb-⁸⁷Sr dating of microscopic samples. In Proc. 12th Lunar Sci. Conf., 1027-1038.

F. Radicati di Brozolo, J. C. Huneke, D. A. Papanastassiou, and G. J. Wasserburg (1981) ³⁹Ar-⁴⁰Ar and Rb-Sr age determinations on quaternary volcanic rocks. Earth Planet. Sci. Lett. 53, 445-456.

G. J. Wasserburg, D. A. Papanastassiou, and T. Lee (1980) Isotopic heterogeneities in the solar system. In "Les éléments et leurs isotopes dans l'Univers", Proc. of the 22nd Liège Int. Astrophys. Symp., pp. 203-253; and in "Early Solar System Processes and the Present Solar System", Soc. Italiana di Fisica, Bologna, pp. 144-191.

F. R. Niederer, D. A. Papanastassiou, and G. J. Wasserburg (1980) Endemic isotopic anomalies in titanium. Astrophys. J. (Letters) 240, L73-L77.

W. A. Russell, D. A. Papanastassiou, and T. A. Tombrello (1980) The fractionation of Ca isotopes by sputtering. Radiation Effects 52, 41-52.

T. M. Esat, D. E. Brownlee, D. A. Papanastassiou, and G. J. Wasserburg (1979) Mg isotopic composition of interplanetary dust grains. Science 206, 190-197.

G. J. Wasserburg, F. Radicati di Brozolo, D. A. Papanastassiou, M. T. McCulloch, J. C. Huneke, R. F. Dymek, D. J. DePaolo, A. A. Chodos, and A. L. Albee (1978) Petrology, chemistry, age and irradiation history of Luna 24 samples. In Mare Crisium: The View from Luna 24, Pergamon Press, New York, pp. 657-678.

W. A. Russell and D. A. Papanastassiou (1978) Calcium isotope fractionation in ion exchange chromatography. Anal. Chem. 50, 1151-1154.

W. A. Russell, D. A. Papanastassiou, and T. A. Tombrello (1978) Ca isotope fractionation on the earth and other solar system materials. Geochim. Cosmochim. Acta 42, 1075-1090.

D. A. Papanastassiou and G. J. Wasserburg (1978) Strontium isotopic anomalies in the Allende meteorite. Geophys. Res. Lett., 5, 595-598.

T. M. Esat, D. A. Papanastassiou, and G. J. Wasserburg (1978) The case of the missing ²⁶Al. In Short papers of the 4th Int. Conf. on Geochronology, Cosmochronology and Isotope Geology, USGS Open File Report 78-701 pp. 106-108.

T. M. Esat, T. Lee, D. A. Papanastassiou, and G. J. Wasserburg (1978) Search for ²⁶Al effects in the Allende FUN inclusion Cl. Geophys. Res. Lett. 5, 807-810.

T. Lee, D. A. Papanastassiou, and G. J. Wasserburg (1978) Ca isotopic anomalies in the Allende meteorite. Astrophys. J. (Letters) 220, L21â€'L25.

M. T. McCulloch, G. J. Wasserburg, and D. A. Papanastassiou (1978) More mysteries from Pandora's box. In Short papers of the 4th Int. Conf. on Geochronology, Cosmochronology & Isotope Geology, USGS Open File Report 78-701, pp. 282-285.

G. J. Wasserburg, T. Lee, and D. A. Papanastassiou (1977) Correlated O and Mg isotopic anomalies in Allende inclusions, II: Magnesium. Geophys. Res. Lett. 4, 299-302.

G. J. Wasserburg, F. Tera, D. A. Papanastassiou, and J. C. Huneke (1977) Isotopic and chemical investigations on Angra dos Reis. Earth Planet. Sci. Lett. 35, 294-316.

G. J. Wasserburg, D. A. Papanastassiou, F. Tera and, J. C. Huneke (1977) Outline of a lunar chronology. Phil. Trans. R. Soc. London A 285, 7-22.

D. A. Papanastassiou, T. Lee, and G. J. Wasserburg (1977) Evidence for ²⁶Al in the solar system. In Comets, Asteroids, Meteorites, A. H. Delsemme, ed., (Univ. of Toledo) pp. 343â€'349.

D. A. Papanastassiou, D. J. DePaolo, and G. J. Wasserburg (1977) Rb-Sr and Sm-Nd chronology and genealogy of mare basalts from the Sea of Tranquility. In Proc. 8th Lunar Sci. Conf., pp. 1639-1672.

W. A. Russell, D. A. Papanastassiou, T. A. Tombrello, and S. Epstein (1977) Ca isotope fractionation on the moon. In Proc. 8th Lunar Sci. Conf., pp. 3791-3805.

T. Lee, D. A. Papanastassiou, and G. J. Wasserburg (1977) ²⁶Al in the early solar system: Fossil or fuel? Ap. J. Letters 211, L107-L110.

T. Lee, D. A. Papanastassiou, and G. J. Wasserburg (1977) Mg and Ca isotopic study of individual microscopic crystals from the Allende meteorite by the direct loading technique. Geochim. Cosmochim. Acta 41, 1473-1485.

T. Lee, D. A. Papanastassiou, and G. J. Wasserburg (1976) Demonstration of ²⁶Mg excess in Allende and evidence for ²⁶Al. Geophys. Res. Lett. 3, 109-112.

D. A. Papanastassiou and G. J. Wasserburg (1976) Rb-Sr age of troctolite 76535. In Proc. 7th Lunar Sci. Conf., pp. 2035â€'2054.

D. A. Papanastassiou and G. J. Wasserburg (1975) Rb-Sr study of a lunar dunite and evidence for early lunar differentiates. In Proc. 6th Lunar Sci. Conf., pp. 1467-1489.

G. J. Wasserburg and D. A. Papanastassiou (1975) Model ages. Nature 259, 159.

T. Lee and D. A. Papanastassiou (1974) Mg isotopic anomalies in the Allende meteorite and correlation with O and Sr effects. Geophys. Res. Lett. 1, 225-228.

F. Tera, D. A. Papanastassiou, and G. J. Wasserburg (1974) Isotopic evidence for a terminal lunar cataclysm. Earth Planet. Sci. Lett. 22, 1-21.

D. A. Papanastassiou and G. J. Wasserburg (1974) Evidence for late formation and young metamorphism in the achondrite Nakhla. Geophys. Res. Lett. 1, 23-26.

D. A. Papanastassiou (1973) Acceptance speech, F. W. Clarke Medal. Geochim. Cosmochim. Acta 37, 1631-1633.

D. A. Papanastassiou and G. J. Wasserburg (1973) Rb-Sr ages and initial strontium in basalts from Apollo 15. Earth Planet. Sci. Lett. 17, 324-337.

C. M. Gray, D. A. Papanastassiou, and G. J. Wasserburg (1973) The identification of early condensates from the solar nebula. Icarus 20, 213-239.

D. A. Papanastassiou and G. J. Wasserburg (1972) Rb-Sr systematics of Luna 20 and Apollo 16 samples. Earth Planet. Sci. Lett. 17, 52-63.

G. J. Wasserburg, J. C. Huneke, D. A. Papanastassiou, F. A. Podosek, F. Tera, and G. Turner (1972) Age determinations on samples from the Apollo 14 landing site. Proc. Seattle COSPAR Meeting, in Space Research XII, pp. 39-41.

D. A. Papanastassiou and G. J. Wasserburg (1972) The Rb-Sr age of a crystalline rock from Apollo 16. Earth Planet. Sci. Lett. 16, 289-298.

D. A. Papanastassiou and G. J. Wasserburg (1972) Rb-Sr age of a Luna 16 basalt and the model age of lunar soils. Earth Planet. Sci. Lett. 13, 368-374.

A. L. Albee, A. A. Chodos, A. J. Gancarz, E. L. Haines, D. A. Papanastassiou, L. Ray, F. Tera, G. J. Wasserburg, and T. Wen (1972) Mineralogy, petrology and chemistry of a Luna 16 basaltic fragment, Sample B-1. Earth Planet. Sci. Lett. 13, 353-367.

G. J. Wasserburg and D. A. Papanastassiou (1971) Age of an Apollo 15 mare basalt: Lunar crust and mantle evolution. Earth Planet. Sci. Lett. 13, 97-104.

D. A. Papanastassiou and G. J. Wasserburg (1971) Rb-Sr ages of igneous rocks from the Apollo 14 mission and the age of the Fra Mauro formation. Earth Planet. Sci. Lett. 12, 36-48.

D. A. Papanastassiou and G. J. Wasserburg (1971) Lunar chronology and evolution from Rb-Sr studies of Apollo 11 and 12 samples. Earth Planet. Sci. Lett. 11, 37-62.

D. A. Papanastassiou and G. J. Wasserburg (1970) Rb-Sr ages from the Ocean of Storms. Earth Planet. Sci. Lett. 8, 269-278.

D. A. Papanastassiou, G. J. Wasserburg, and D. S. Burnett (1970) Rbâ€'Sr ages of lunar rocks from the Sea of Tranquility. Earth Planet. Sci. Lett. 8, 1-19.

A. L. Albee, D. S. Burnett, A. A. Chodos, E. L. Haines, J. C. Huneke, D. A. Papanastassiou, F. A. Podosek, G. P. Russ, and G. J. Wasserburg (1970) Mineralogic and isotopic investigations on lunar rock 12013. Earth Planet. Sci. Lett. 9, 137-163.

A. L. Albee, D. S. Burnett, A. A. Chodos, O. Eugster, J. C. Huneke, D. A. Papanastassiou, F. A. Podosek, G. P. Russ, H. G. Sanz, F. Tera, and G. J. Wasserburg (1970) Ages, irradiation history and chemical composition of lunar rocks from the Sea of Tranquility. Science 167, 463-466.

D. A. Papanastassiou (1970) The determination of small time differences in the formation of planetary objects. Ph.D. Thesis, California Institute of Technology.

G. J. Wasserburg, D. A. Papanastassiou, and H. G. Sanz (1969) Initial strontium for a chondrite and the determination of a metamorphism or formation interval. Earth Planet. Sci. Lett. 7, 33-43.

G. J. Wasserburg, D. A. Papanastassiou, E. V. Nenow, and C. A. Bauman (1969) A programmable magnetic field mass spectrometer with onâ€'line data processing. Rev. Sci. Instrum. 40, 288-295.

D. A. Papanastassiou and G. J. Wasserburg (1969) Initial strontium isotopic abundances and the resolution of small time differences in the formation of planetary objects. Earth Planet. Sci. Lett. 5, 361-376.

EXTENDED ABSTRACTS

(Last 9 years)

J.H. Chen, D.A. Papanastassiou, M. Telus, and G.R. Huss (2013) Fe-Ni isotopic systematics in UOC QUE97008 and Semarkona chondrules. 44th Lunar and Planetary Science Conference, Abstract #2649.

D.A. Papanastassiou, J.H. Chen, and B.P. Weiss (2013) Fe-Ni isotope systematics in the Eagle Station pallasite. 44th Lunar and Planetary Science Conference, Abstract #2607.

D. A. Papanastassiou, J.H. Chen, and B.P. Weiss (2012) Mn-Cr isotopic systematics in the Eagle Station pallasite, 43rd Lunar and Planetary Science Conference, Abstract #2684.

J.H. Chen, D. A. Papanastassiou, J. Zhang, N. Dauphas and A.M. Davis (2012) Correlated Ca, Ti, and Cr isotopic anomalies in meteorites. 43rd Lunar and Planetary Science Conference, Abstract #2607.

J.H. Chen, D.A. Papanastassiou, N. Dauphas (2011) Anomolous Ca isotopic compositions in leacheates of Murchison. 42nd Lunar and Planetary Science Conference, Abstract #2440.

D.A. Papanastassiou, J.H. Chen (2011) Revisiting Cr in the Eagle Station pallasite and its suggested affinities to carbonaceous chondrites. 42nd Lunar and Planetary Science Conference, Abstract #2195.

D. A. Papanastassiou, J. H. Chen, and N. Dauphas (2010) Anomalous ⁵³Cr and ⁵⁴Cr and nearly normal Ni in differential dissolution steps of Murchison. 41^st Lunar and Planetary Science Conference (2010), Abstract #2068.

S. de Leuw, D. A. Papanastassiou, and J. T. Wasson (2010) Chromium isotopes in chondrites and the heterogeneous accretion of the solar nebula. 41^st Lunar and Planetary Science Conference, Abstract #2703.

B. L. Jolliff, L. Alkalai, C. M. Pieters, J. W. Head III, and D. A. Papanastassiou, E. B. Bierhaus (2010) Sampling the South Pole-Aitken Basin: Objectives and Site Selection Criteria. 41^st Lunar and Planetary Science Conference, Abstract #2450.

J. H. Chen, D. A. Papanastassiou, and N. Dauphas (2010) Anomalous Cr-54 and Cr-53 in Bulk Acid Residues from Orgueil and Murchison. 41^st Lunar and Planetary Science Conference, Abstract #2005.

G. J. Wasserburg, G. Caro, and D. A. Papanastassiou (2010) ⁴⁰Ca Isotopic Evolution of the Oceans and Crust and the Major Role of Hydrothermal Circulation Over Geologic Time. 41st Lunar and Planetary Science Conference (2010), Abstract #1924.

B. P. Weiss, L. Carporzen, L. T. Elkins-Tanton, D. L. Shuster, D. S. Ebel, J. Gattacceca, M. T. Zuber, J. H. Chen, D. A. Papanastassiou, R. P. Binzel, D. Rumble, and A. J. Irving (2010) A partially differentiated body for CV chondrites? 41^st Lunar and Planetary Science Conference (2010), Abstract #1688.

N. Dauphas, L. Remusat, J. H. Chen, J. Stodolna, M. Roskosz, Y. Guan, J. M. Eiler, and D. A. Papanastassiou (2010) A coordinated search for the carrier of ⁵⁴Cr anomalies in meteorites.41^st Lunar and Planetary Science Conference, Abstract #107.

J. H. Chen and D. A. Papanastassiou (2009) Nickel isotopic compositions in pallasites and iron meteorites. 40^th Lunar and Planetary Science Conference, Abstract #1844.

J. H. Chen and D. A. Papanastassiou (2008) The Concordancy of uranium-lead ages in meteorites. 39^thLunar and Planetary Science Conference, Abstract #1956.

D. A. Papanastassiou (2007) Overview of Short-lived Nuclides: The elusive road to consistency. Workshop on the Chronology of Meteorites and the Early Solar System, Abstract #4056.

M. Bizzarro, J.-L. Birck, J. H. Chen, G. Huss, G. Lugmair, S. Mostefaoui, D. A. Papanastassiou, A. Shukolyukov, G. Quitté, S. Tachibana, M. Wadhwa (2007) Nickel isotope anomalies in meteorites and the ⁶⁰Fe-⁶⁰Ni clock. Workshop on the Chronology of Meteorites and the Early Solar System, Abstract #4015.

J. H. Chen, D. A. Papanastassiou (2006) Nickel isotope investigations by MC-ICP-MS and PTIMS. 37^th Lunar and Planetary Science Conference, Abstract #1997.

D. A. Papanastassiou, J. H. Chen (2006) Comparison of MC-ICP-MS and NTIMS Ru endemic isotope anomalies in meteorites. 37^th Lunar and Planetary Science Conference, Abstract #1976.

S. de Leuw, J. T. Wasson, A. E. Rubin, D. A. Papanastassiou (2006) Petrographic search for the carriers of isotopically anomalous chromium in carbonaceous chondrites. 37^thLunar and Planetary Science Conference, Abstract #1352.

C. Holmden, B. M. Eglington, and D. A. Papanastassiou (2005) High mass resolution plasma mass spectrometry of Cr isotopes. Geochim. Cosmochim Acta Supplement 69 Goldschmidt Conf. Abstracts. p. A552.

D. A. Papanastassiou, G. J. Wasserburg, and O. Bogdanovski (2005) The ⁵³Mn-⁵³Cr system in CAIs: an update. 36^th Lunar and Planetary Science Conference, Abstract #2198.

J. H. Chen and D. A. Papanastassiou (2005) The palladium isotopic composition in iron meteorites. 36^th Lunar and Planetary Science Conference, Abstract #1495.

D. A. Papanastassiou, J. H. Chen, and G. J. Wasserburg (2004) More on Ru endemic isotope anomalies in meteorites. 35^th Lunar and Planetary Science Conference, Abstract #1828.

J. H. Chen, D. A. Papanastassiou, G. J. Wasserburg, and H. H. Ngo (2004) Endemic Mo isotopic anomalies in iron and carbonaceous meteorites. 35^th Lunar and Planetary Science Conference, Abstract #1431.

Most earlier extended abstracts can be searched for and found at:

NASA ADS http://www.adabs.harvard.edu and

Lunar and Planetary Institute, USRA, http://www.lpi.usra.edu/publications/meetingpubs.shtml