Lars E Borg

Staff Scientist/Chemist
Nuclear and Chemical Sciences Division
Phone: +19254245722


  • Ph.D., Isotope Geochemistry, University of Texas at Austin, 1995
  • M.A., Igneous Petrology, University of Texas at Austin, 1989
  • B.A., Earth Science and Paleontology, University of California at Berkeley, 1985

Research Interests

Lars Borg is a chemist working in the LLNL Chemical & Isotopic Signatures group. His research interests include geochronology and geochemistry of samples from asteroids, the Moon, and Mars to constrain the nature and timing of processes occurring in the proto-planetary disk and planetary bodies early in the history of the solar system. In particular, he is interested in constraining the sources of nucleosynthetic materials in the nascent solar nebula using stable heavy isotopes and the defining timing of the formation and differentiation of the terrestrial planets using long- and short-lived isotopic chronometers.

In addition to his research at LLNL, Borg serves on the NASA Advisory Council, Planetary Sciences Subcommittee; the Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM); and the Mars Exploration Program and Analysis Group (MEPAG), Goals Committee. While serving on these committees, Borg has provided scientific input and advice to NASA on science and exploration policy, sample collection and curation issues, the allocation of extraterrestrial materials collected during space missions, and planning and prioritizing Mars exploration activities.

Committees Served

  • NASA Advisory Council: Planetary Sciences Subcommittee
    • NASA science advisory subcommittee on science and exploration policy
  • Curation and Analysis Planning Team for Extraterrestrial Materials (CAPTEM): Chair Lunar allocation Subcommittees
    • Advise NASA Science Mission Directorate on sample collection and curation issues and allocate extraterrestrial materials collected during NASA space missions
  • Mars Exploration Program and Analysis Group (MEPAG): Goals Committee
    • Provide science input for planning and prioritizing Mars exploration activities for the next several decades to Mars Exploration Program Office

Selected Publications

  1. Borg L. E., Connelly J. N., Cassata W., Gaffney A. M., and Bizzarro M. (2017). Chronologic implications for slow cooling of troctolite 76535 and temporal relationships between the Mg-suite and the ferroan anorthosite suite. Geochimica et Cosmochimica Acta 201, 377–391. LLNL-JRNL-660422.
  2. Brennecka G. A., Borg L. E., Romaniello S. J., Sounders A. K., Shollenberger Q. R., Marks N. E., and Wadhwa M. (2017). A renewed search for short-lived 126Sn in the early Solar System: Hydride generation MC-ICPMS for high sensitivity Te isotopic analysis. Geochimica et Cosmochimica Acta 201, 331–344. LLNL-JRNL-704743.
  3. Herd C., Walton E. L., Agee C. B., Muttik N., Zeigler K., Shearer C. K., Bell A. S., Santos A. R., Burger P. V., Simon J. I., Tappa M. J., McCubbin F. M., Gattacceca J., Lagroix F., Sanborn M. E., Yin Q. -Z., Cassata W. S., Borg L. E., Lindvall R. E., Kruijer T. S., Brennecka G. A., Kleine T., Nishiizumi K. and CaffeeM. W. (2017). The Northwest Africa 8159 martian meteorite: Expanding the martian sample suite to the early Amazonian. Geochimica et Cosmochimica Acta 218, 1–26. LLNL-JRNL-739213.
  4. Kruijer T. S., Kleine T., Borg L. E., Brennecka G. A., Irving T. J., Bischoff A., and Agee C. B. (2017). The early differentiation of Mars inferred from Hf–W chronometry. Earth and Planetary Science Letters 474, 345–354. LLNL-JRNL-72834.
  5. Borg L. E., Brennecka G. A., and Symes S. J. K. (2016). Accretion timescale and impact history of Mars deduced from the isotopic systematics of martian meteorites. Geochimica et Cosmochimica Acta 175, 150–167. LLNL-JRNL-700773.
  6. Burkhardt C. Borg L. E., Brennecka G. A., Shollenberger Q. R., Dauphas N., and Kleine T. (2016). A nucleosynthetic origin for the Earth’s anomalous 142Nd composition. Nature 537, 394–398. LLNL-JRNL-689320.
  7. Shearer C. K., Elardo S. M., Petro N. E., Borg L. E., and McCubbin F. M. (2015). Origin of the lunar highlands Mg-suite: An integrated petrology, geochemistry, chronology, and remote sensing perspective. American Mineralogist 100, 294–325. LLNL-JRNL-700774.
  8. Borg L. E., Gaffney A. M., and Shearer C. K. (2015). A review of lunar chronology revealing a preponderance of 4.34–4.37 Ga ages. Meteoritics & Planetary Science 50, 715–732. LLNL-JRNL-655538.
  9. Gaffney A. M., and Borg L. E. (2014). A young age for the lunar magma ocean. Geochimica et Cosmochimica Acta 140, 227–240. LLNL-JRNL-654029.
  10. Brennecka G. N., Borg L. E., Wadhwa, M. (2014). Insights into the Martian mantle: The age and isotopics of the meteorite fall Tissint. Meteoritics & Planetary Science 49, 412–418. LLNL-JRNL-754436.