Phone: 973-720-2695 2695
Department: Environmental Science
Position: Assistant Professor
Area Specialization: Isotope geochemistry, palaeoclimatology
Education and Appointments:
2010-2012 - NOAA/UCAR Climate and Global Change Postdoctoral Fellow, UC Irvine
2010 - PhD, University of Newcastle, Australia
2006 - MSc, University of Massachusetts, Amherst
2004 - BSc, University of Wollongong, Australia
Broadly speaking, my research goals are focused on gaining a deeper understanding of how Earth's climate has changed in the past, and how we can use this knowledge to better predict future changes under an anthropogenic greenhouse gas-induced warming planet. More specific, my research involves using geochemical tracers preserved in cave-carbonate deposits (speleothems) to reconstruct the Quaternary (i.e. last approx. 2 million years) history of climate variability in tropical Australasia. I am particularly focused on building high-resolution and well-dated paleoclimate records—using stable isotopes (of C and O) and trace elements (Mg, Sr, Ba, P, U) as tracers for past environmental changes—to better understand the role of the tropics in global climate change over a range of time periods (e.g. glacial-interglacial, the Common Era). Whilst the environmentally-sensitive geochemical tracers preserved in the speleothems are primarily controlled by fluctuations in temperature, rainfall, and/or the overlying vegetation (above the cave), the underlying processes controlling the cycling of these tracers through the atmosphere, soil, and karst systems are extremely complex. Hence, my research employs a multi-pronged approach of combining modern cave drip-water studies and geochemical modeling, with the chemical and physical analysis of fossil stalagmites, to gain a deeper understanding of how these processes govern the isotopic and trace-elemental signals in the cave carbonate; understanding these processes is essential for robust environmental interpretations of the natural archives. I currently have ongoing projects in SE Asia (Laos), Indonesia, and northern Australia, where I am collaborating with colleagues from UC Irvine (Kathleen Johnson, Hongying Yang), the Australian National University (Mike Gagan, Linda Ayliffe), and the University of Melbourne (Russell Drysdale, John Hellstrom, Jon Woodhead).
Another key aspect of my research involves merging cave records with Global Climate Model (GCM) simulations. Specifically, I am interested in using speleothems to help validate/improve the performance of GCMs, and in particular, assessing how well they simulate the Australasian monsoon systems over the past millennium. The GCM results are also being used to test different hypotheses regarding the mechanisms for past ocean-atmospheric circulation in Australasia. For this aspect of my research I am collaborating with colleagues from NASA GISS (Ben Cook, Allegra LeGrande).
Griffiths, M.L., Drysdale, R.N., Gagan, M.K., Hellstrom, J.C., Couchoud, I., Vonhof, H.B., Ayliffe, L.K., Hantoro, W.S., 2013. Australasian monsoon response to Dansgaard-Oeschger event 21 and teleconnections to higher latitudes. In press, Earth and Planetary Science Letters. [Link]
Reeves, J.M., Barrows, T.T., Cohen, T.J., Kiem, A.S., Bostok, H.C., Fitzsimmons, K.E., Jansen, J.D., Kemp, Krause, C., Petherick, L., Phipps, S.J., OZ-INTIMATE Members, 2013. Climate variability over the last 35,000 years recorded in marine and terrestrial archives in the Australian region: an OZ-INTIMATE compilation. In press, Quaternary Science Reviews. [Link]
Reeves, J.M., Bostock, H.C., Ayliffe, L.K., Barrows, T.T., , De Decker, P, Devreindt, L., Dunbar, G.B., Drysdale, R.N., Fitzsimmons, K., Gaga, M.K., Griffiths, M.L., Haberle, S.G., Jansen, J.D., Krause, C., Lewis, S., McGregor, H.V., Mooney, S.D., Moss, P., Nanson, G.C., Purcell, A., van der Kaars, S. Palaeoenvironmental change in tropical Australasia over the last 30,000 years – a synthesis by the OZ-INTIMATE group. In press, Quaternary Science Reviews. [Link]
Griffiths, M.L., Drysdale, R.N., Gagan, M.K., Zhao, J.-x., Hellstrom, J.C., Ayliffe, L.K., Hantoro, W.S., Suwargadi, B.W., 2012. Abrupt increase in east Indonesian rainfall from flooding of the Sunda Shelf ~9,500 years ago. In press, Quaternary Science Reviews. [Link]
Griffiths, M.L., Drysdale, R.N., Hua, Q., Fohlmeister, J., Johnson, K., Hellstrom, J.C., Gagan, M.K., Zhao, J.-x., 2012. Hydrological control of the dead carbon fraction in a tropical Holocene speleothem. Quaternary Geochronology 14, 81-93. [Link]
Griffiths, M.L., Drysdale, R. N., Vonhof, H.B., Gagan, M.K., Zhao, J-x., Ayliffe, L.K., Hantoro, W.S., Hellstrom, J.C., Cartwright, I., Frisia, S., Suwargadi, B.W., 2010. Younger Dryas-Holocene temperature and rainfall history of southern Indonesia from δ18O in speleothem calcite and fluid inclusions. Earth and Planetary Science Letters 295, 30-36. [Link]
Griffiths, M.L., Drysdale, R.N., Gagan, M.K., Ayliffe, L.K., Frisia, S., Zhao, J.-x., Hellstrom, J.C., Fischer, M.J., Hantoro, W.S., Feng, Y.-x., Suwargadi, B.W., 2010. Evidence for Holocene changes in Australian-Indonesian monsoon rainfall from stalagmite trace element and stable isotope ratios. Earth and Planetary Science Letters 292, 27-38. [Link]
Griffiths, M.L., Drysdale, R.N., Gagan, M.K., Zhao, J.-x., Ayliffe, L.K., Hellstrom, J.C., Hantoro, W.S., Frisia, S., Feng, Y.-x., Cartwright, I., St. Pierre, E., Fischer, M.J., Suwargadi, B.W., 2009. Increasing Australian-Indonesian monsoon rainfall linked to early Holocene sea-level rise. Nature Geoscience 2, 636-639. [Link] [Backstory]
Griffiths, M.L., and Bradley, R.S., 2007. Variations of Twentieth Century Temperature and Precipitation Extreme Indicators in the Northeast United States. Journal of Climate 20, 5401-5417. [Link]
Publications in review
Ayliffe, L.K., Gagan, M.K., Zhao, J.-x., Drysdale, R.N., Hellstrom, J.C., Griffiths, M.L, Hantoro, W.S., Cowley, J., Scott-Gagan, H., Suwargadi, B.W. Millennial-scale changes in the Australasian monsoon during the last deglaciation. In review.
Griffiths, M.L., Kimbrough, A.K., Gagan, M.K., Drysdale, R.N., Cole, J., Johnson, K., Zhao, J.-x., Hellstrom, J.C., Hantoro, W.S. An annually-resolved reconstruction of Indo-Pacific hydrology over the past 2,000 years. In revision.