Leah E Morgan, Ph.D.

Biography

I joined the ⁴⁰Ar/³⁹Ar geochronology lab at the USGS in Denver, Colorado as a research geologist in 2015. I was previously a Marie Curie postdoctoral fellow at the Scottish Universities Environmental Research Center and at the Vrije Universiteit Amsterdam. I received a PhD from the University of California at Berkeley in 2009, and a BA from Carleton College in 2004. I was born and raised in Vermont.

I have worked on a range of applications and method development issues in ⁴⁰Ar/³⁹Ar geochronology. Applications have largely focused on questions in paleoanthropology and the geologic timescale. Method development projects include developing metrologically traceable systems for measuring absolute quantities of ⁴⁰Ar and ⁴⁰K, and the design of a mobile neutron source for the future in situ deployment of ⁴⁰Ar/³⁹Ar capabilities on planetary surfaces.

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Publications

Righter, K., M.A. Cosca, and L.E. Morgan, 2016. Preservation of ancient impact ages on the R chondrite parent body: 40Ar/39Ar age of hornblende‐bearing R chondrite LAP 04840. Meteoritics & Planetary Science, 51 (9), 1678-1684.

Morgan, L.E., 2016. ⁴⁰Ar/³⁹Ar and K-Ar Geochronology, in: A.S. Gilbert (ed.), Encyclopedia of Geoarchaeology. Springer.

Morgan, L.E., and B. Davidheiser-Kroll, 2015. Pressure disequilibria induced by rapid valve closure in noble gas extraction lines. Geochemistry, Geophysics, Geosystems, 16, doi:10.1002/2015GC005823.

Morgan, L.E., 2015. Noble Gas Mass Spectrometry, in: W.J., and J.W. Thompson (eds.), Encyclopedia of Scientific Dating Methods. Springer.

Sahle, Y., L.E. Morgan, D.R. Braun, W.K. Hutchings, 2014. Chronological and behavioral contexts of the earliest Middle Stone Age in the Gademotta Formation, Main Ethiopian Rift, Quaternary International, v. 331, p. 6-19.

Mark, D.F., M. Petraglia, V.C. Smith, L.E. Morgan, D.N. Barfod, B.S Ellis, N.J. Pearce, J.N. Pal, R. Korisettar, 2014. A high-precision ⁴⁰Ar/³⁹Ar age for the Young Toba Tuff and dating of ultra- distal tephra: forcing of Quaternary climate and implications for hominin occupation of India, Quaternary Geochronology, v. 21, p. 90-103.

Sahle, Y., W.K. Hutchings, D.R. Braun, J.C. Sealy, L.E. Morgan, A. Negash, B. Atnafu, 2013. Earliest stone-tipped projectiles from the Ethiopian Rift date to >279,000 years ago. PLOS ONE, v. 8, no. 11, e78092.

Morgan, L.E., D.F. Mark, J. Imlach, D.N. Barfod, 2013. FCs-EK: A new sampling of the Fish Canyon tuff ⁴⁰Ar/³⁹Ar neutron flux monitor, in: Jourdan, F., Mark, D., and Verati, C. (eds.), Advances in ⁴⁰Ar/³⁹Ar Dating: from Archaeology to Planetary Sciences. Geological Society, London, Special Publications, 378.

Renne, P.R., A.L. Deino, F.J. Hilgen, K.F. Kuiper, D.F. Mark, W.S. Mitchell, L.E. Morgan, R. Mundil, J. Smit, 2013. Timescales of critical events around the Cretaceous-Paleogene boundary. Science, v. 339, p. 684-687.

Schoene, B., D.J. Condon, L.E. Morgan, N. McLean, 2013. Precision and accuracy in geochronology. Elements Magazine, v.9, no.1, p. 23-28.

Renne, P.R., S.R. Mulcahy, W.S. Cassata,, L.E. Morgan, S.P. Kelley, L. Hlusko, J. Njau, 2012. Retention of inherited Ar by alkali feldspar xenocrysts in a magma: Kinetic constraints from Ba zoning profiles. Geochimica et Cosmochimica Acta, v. 93, p. 129-142.

Morgan, L.E., P.R. Renne, R. Galotti, G. Kieffer, M. Piperno, J.-P. Raynal, 2012. A chronological framework for a long and persistent archeological record: Melka Kunture, Ethiopia. Journal of Human Evolution, v. 62, no. 1, p. 104-115.

Frost, S.R., H.L. Schwartz, L. Giemsch, L.E. Morgan, P.R. Renne, M. Wildgoose, C. Saanane, F. Schrenk, K. Harvati, 2012. Refined age estimates and paleoanthropological investigation of the Manyara Beds, Tanzania. Journal of Anthropological Sciences, v. 90, p. 151-161.

Schwartz, H., P.R. Renne, L.E. Morgan, M.M. Wildgoose, P.C. Lippert, S.R. Frost, K. Harvati, F. Schrenk, C. Saanane, 2012. Geochronology of the Manyara Beds, northern Tanzania: stratigraphy and new magnetostratigraphy and ⁴⁰Ar/³⁹Ar ages. Quaternary Geochronology, v. 7, no. 1, p. 48-66.

Morgan, L.E., O. Postma, K.F. Kuiper, D.F. Mark, W. van der Plas, S. Davidson, M. Perkin, I. Villa, J.R. Wijbrans, 2011. A metrological approach to measuring ⁴⁰Ar* concentrations in K-Ar and ⁴⁰Ar/³⁹Ar mineral standards, Geochem. Geophys. Geosyst., v. 12, p. A0AA20, doi:10.1029/2011GC003719.

Renne, P.R., A.L. Deino, W.E. Hames, M.T. Heizler, S.R. Hemming, K.V. Hodges, A.A.P. Koppers, D.F. Mark, L.E. Morgan, D. Phillips, B.S. Singer, B.D. Turrin, I.M. Villa, M. Villeneuve and J.R. Wijbrans, 2009. Data reporting norms for ⁴⁰Ar/³⁹Ar geochronology. Quaternary Geochronology, v. 4, no. 5, p. 346-352.

Renne, P.R., W.S. Cassata, and L.E. Morgan, 2009. The isotopic composition of atmospheric argon and ⁴⁰Ar/³⁹Ar geochronology: time for a change? Quaternary Geochronology, v. 4, no. 4, p. 288-298.

Renne, P. R., L.E. Morgan, G. WoldeGabriel, W.K. Hart, Y. Haile-Selassie, and T.D. White, 2009. ⁴⁰Ar/³⁹Ar Ages of the Middle Awash Late Miocene, in: Haile-Selassie, Y., and WoldeGabriel, G. (eds.), Ardipithecus kadabba: Late Miocene evidence from the Middle Awash, Ethiopia. University of California Press, Berkeley, CA.

Morgan, L.E., P.R. Renne, R.E. Taylor, and G. WoldeGabriel, 2009. Archaeological age constraints from eruption ages of obsidian: Examples from the Middle Awash, Ethiopia. Quaternary Geochronology, v. 4, p. 193-203.

Morgan, L.E. and P.R. Renne, 2008. Diachronous Dawn of Africa’s Middle Stone Age: New ⁴⁰Ar/³⁹Ar ages from the Ethiopian Rift. Geology, v. 36, no. 12, p. 967-970.

Gihring, T.M., L.-H. Lin, M. Davidson, T.C. Onstott, L. Morgan, M. Milleson, T.L. Kieft, E. Trimarco, D.L. Balkwill, and M.E. Dollhopf, 2006. The Distribution of Microbial Taxa in the Subsurface Water of the Kalahari Shield, South Africa. Geomicrobiology Journal, v. 23, p. 415-430.