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Dr Micha Ruhl

Assistant Professor in Sedimentology

Email: ruhlm@tcd.ie
Tel: + 353 1 896 1165 
Office: Museum Building, Office 0.18C
Google Scholar ID:   Dr. Micha Ruhl
ORCID:   Micha Ruhl

Research

See more of my research at: www.micharuhl.com

In my research I apply Sedimentology, Integrated (chemo-, bio-, cyclo-, magneto) Stratigraphy and Low-Temperature Geochemistry to study a diverse range of topics related to Palaeoclimatic & -environmental Change, Mass Extinctions, and (changes in) Depositional Environments.

Depositional environments: The formation and the physical, biogenic and geochemical characteristics of sediments that are deposited in marine and terrestrial (also lacustrine) sedimentary basins depend on (changes in) sediments supplied, sediment fluxes and climatic and environmental conditions that control the depositional environment. I am interested in understanding local processes and the internal forcing mechanisms in the Earth system that control (changes in) marine and terrestrial depositonal environments, on a basinal, regional and global scale. For example I study past major events in the Earth system that led to the widespread formation of organic-rich black shales (such as during Oceanic Anoxic Events (OAEs)). With this, I also aim to constrain processes that led to hydrocarbon source-rock formation and the stratigraphical and geographical variations therein.

Palaeoclimatic & -environmental Change, Large Igneous Province volcanism, Astronomical forcing and changes in global (bio)geochemical cycles:
Earth’s climate and the environment have changed on multiple temporal (101-107 yr) and geographical (local–global) scales. I am interested in understanding the (causative) internal and external forcing mechanisms and positive and negative feedback processes that controlled Earth’s climate and environment. More particularly, I am interested in understanding (1) the many ways in which Large Igneous Province (LIP) volcanism impacted on global climate and environments, global biodiversity (mass extinction/evolution) and changes in global (bio)geochemical cycles; (2) how external processes, such as astronomical forcing, impacted global climates, environments and local sedimentary depositional conditions; and (3) constraining background conditions in the global climate & environment, as well as in global (bio)geochemical cycling.

Geo- and Astrochronology: Understanding the absolute and/or relative age of sedimentary successions, and the rate of change in physical, biological and geochemical parameters recorded therein, is essential for understanding the underlying processes that controlled (changes in) Earth’s climate, environment and depositional conditions. I study sedimentary successions and integrate chemo-, bio-, magneto and cyclostratigraphy with radio-isotope chronology, to constrain (1) the rate of change in past climates, environments, biodiversity and (bio)geochemical cycling (for example during Global Change Events, Mass Extinction Events, and OAEs), and (2) constrain detailed relative and absolute time-scales throughout Earth history.

Teaching

I currently teach the GLU33926 Sedimentology (3rd yr) and GLU44902 Fieldwork (4th yr) modules

Peer-reviewed Publications:


(Google Scholar: Citations: >880 – H-index: 15 – i10-index: 18)

  1. Hillebrandt, A. v., Krystyn, L., Kürschner, W.M., Bonis, N.R., Ruhl, M., Urlichs, M., with contributions by Bown, P., Kment, K., McRoberts, C., Simms, M., Tomasovych, A. A candidate GSSP for the base of the Jurassic in the Northern Calcareous Alps (Kuhjoch section; Karwendel Mountains, Tyrol, Austria).  International Subcommission on Jurassic Stratigraphy Newsletter 34 (1), 2-20 (2007).

  2. Ruhl, M., Kürschner, W.M., Krystyn, L. Triassic-Jurassic organic carbon isotope stratigraphy of key sections in the western Tethys realm (Austria).  Earth and Planetary Science Letters 281 (3-4): 169-187 (2009).

  3. Deenen, M.H.L., Ruhl, M., Bonis, N.R., Krijgsman, W., Kürschner, W.M., Reitsma, M. and Bergen, M.J. v. A new chronology for the end-Triassic mass extinction.  Earth and Planetary Science Letters 291 (1-4): 113-125 (2010).

  4. Ruhl, M., Veld, H., Kürschner, W.M. Sedimentary organic matter characterization of the Triassic–Jurassic boundary GSSP at Kuhjoch (Austria).  Earth and Planetary Science Letters 292 (1-2): 17-26 (2010).

  5. Bonis, N.R., Ruhl, M. and Kürschner, W.M. Milankovitch-scale palynological turnover across the Triassic-Jurassic transition at St. Audrie’s Bay, SW UK.  Journal of the Geological Society, London 167: 877-888 (2010).

  6. Bonis, N.R., Ruhl, M., Kürschner, W.M. Climate change driven black shale deposition during the end-Triassic in the western Tethys.     Palaeogeography, Palaeoclimatology, Palaeoecology 290 (1-4): 151-159 (2010).

  7. Ruhl, M., Deenen, M.H.L., Abels, H.A., Bonis, N.R., Krijgsman, W., Kürschner, W.M. Astronomical constraints on the duration of the early Jurassic Hettangian stage and recovery rates following the end-Triassic mass extinction (St. Audrie’s Bay/ East Quantoxhead, UK).     Earth and Planetary Science Letters 295 (1-2): 262-276 (2010).

  8. Deenen, M.H.L., Krijgsman, W., Ruhl, M. The quest for E23r at Partridge Island (Bay of Fundy): CAMP emplacement post-dating the end-Triassic extinction event in Canada.     Canadian Journal of Earth Sciences 48, 1282-1291 (2011).

  9. Ruhl, M. & Kürschner, W.M. Multiple phases of carbon-cycle disturbance from Large Igneous Province formation at the Triassic-Jurassic transition.     Geology 39 (5), 431-434 (2011).

  10. Ruhl, M., Bonis N.R., Reichart, G.-J., Sinninghe Damsté, J.S., Kürschner, W.M. Atmospheric methane injection caused end-Triassic mass extinction.     Science 333, 430 (2011).

  11. Hillebrandt, A.v., Krystyn, L., Kurschner, W.M., Bonis, N.R., Ruhl, M., Richoz, S., Schobben, M. A. N., Urlichs, M., Bown, P.R., Kment, K., McRoberts, C.A., Simms, M., Tomasových, A. The Global Stratotype Sections and Point (GSSP) for the base of the Jurassic System at Kuhjoch (Karwendel Mountains, Northern Calcareous Alps, Tyrol, Austria).     Episodes 36 (3), 162-198 (2013).

  12. Dahl, T.W., Ruhl, M., Hammarlund, E.U., Canfield, D.E., Rosing, M.T., Bjerrum, C.J. Tracing euxinia by molybdenum concentrations in sediments using handheld x-ray fluorescence spectroscopy (HHXRF).     Chemical Geology 360–361, 241–251 (2013).

  13. Hesselbo, S. Bjerrum, C.J., Hinnov, L., MacNiocaill, C., Miller, K., Riding, J., Van de Schootbrugge, B. and the Mochras Revisited Science Team. Mochras Revisited: A New Global standard for Early Jurassic Earth History.     Scientific Drilling 16, 81–91 (2013).

  14. Hüsing, S., Beniest, A., van der Boon, A., Deenen, M.H.L. Ruhl, M., Krijgsman, W. Magnetostratigraphy of the Lower Jurassic marine successions at St. Audrie’s Bay and East Quantoxhead (Hettangian-Sinemurian; Somerset, UK).     Palaeogeography, Palaeoclimatology, Palaeoecology 403, 43–56 (2014).

  15. Ullmann, C., Hesselbo, S., Ruhl, M., Thibault, N, Korte, C. Effect of a Jurassic Oceanic Anoxic Event on belemnite ecology and evolution.     PNAS 111 (28), 10073–10076 (2014).

  16. Percival, L.M.E., Witt, M.L.I., Mather, T.A., Hermoso, M., Jenkyns, H.C., Hesselbo, S.P., Al-Suwaidi, A.H., Storm, M.S., Xu, W., Ruhl, M. Globally enhanced mercury deposition during the end-Pliensbachian extinction and Toarcian OAE: A link to the Karoo–Ferrar Large Igneous Province.     Earth and Planetary Science Letters 428, 267-280 (2015).

  17. Korte, C., Hesselbo, S.P., Ullmann, C.V., Dietl, G., Ruhl, M., Schweigert, G., Thibault, N. Jurassic climate mode governed by ocean gateway.  Nature Communications 6 (10015), doi:10.1038/ncomms10015 (2015).

  18. Jenkyns, H.C., Dickson, A.J., Ruhl, M., Van der Boorn, S. Basalt–seawater interaction, the Plenus Cold Event, enhanced weathering and geochemical change: deconstructing Oceanic Anoxic Event 2 (Cenomanian–Turonian, Late Cretaceous).  Sedimentology, in press, doi: 10.1111/sed.12305 (2016).

  19. Robinson, S.A., Ruhl, M., Astley, D.L., Naafs, B.D.A., Farnsworth, A.J., Bown, P.R., Jenkyns, H.C., Lunt, D.J., O’Brien, C., Pancost, R.D., Markwick, P.J. Early Jurassic North Atlantic sea-surface temperatures from TEX86 palaeothermometry.  Sedimentology, in press, doi: 10.1111/sed.12321 (2016).

  20. Xu, W., Ruhl, M., Hesselbo, S.P., Riding, J.B., Jenkyns, H.C., Orbital pacing of Early Jurassic (Sinemurian) carbon-cycle and environmental change as a cause for source-rock formation and seabed methane seepage.  Sedimentology, in press, doi: 10.1111/sed.12329 (2016).

  21. Mette, W., Thibault, N., Krystyn, L., Korte, C., Clemence, M.-E., Ruhl, M., Rizzi, M., Ullmann, C.V., Rhaetian (Late Triassic) biotic and carbon isotope events and intraplatform basin development in the Northern Calcareous, Alps, Tyrol, Austria.  Geo. Alp 13, 233–256 (2016).

  22. Ruhl, M., Hesselbo, S.P., Hinnov, L., Jenkyns, H.C., Xu, Weimu, Riding, J.B., Storm, M., Minisini, D., Ullmann, C.V., Leng, M.J. Astronomical constraints on the duration of the Early Jurassic Pliensbachian Stage and global climatic fluctuations.  Earth and Planetary Science Letters 455, 149–165 (2016).

  23. Korte, C., Thibault, N., Ullmann, C.V., Clémence, M.-E.; Mette, W., Olsen, T.K., Rizzi, M., Ruhl, M., Brachiopod biogeochemistry and isotope stratigraphy from the Rhaetian Eiberg section in Austria: potentials and limitations.  Neues Jahrbuch für Geologie und Paläontologie – Abhandlungen 284, 2, 117-138(22) (2017).

  24. Xu, W., Ruhl, M., Jenkyns, H.C., Hesselbo, S.P., Riding, J.B., Selby, D., Naafs, B.D.A., Weijers, J.W.H., Pancost, R.D., Tegelaar, E.W., Idiz, E.F., Carbon sequestration in an expanded lake system.  Nature Geoscience 10, 129–134 (2017) doi:10.1038/ngeo2871.

  25. Percival, L.M.E., Ruhl, M., Hesselbo, S.P., Jenkyns, H.C., Mather, T.A., Whiteside, J.H., Mercury evidence for pulsed volcanism during the end-Triassic mass extinction.  Proceedings of the National Academy of Sciences of the United States of America (PNAS) 114, 30, 7929–7934 (2017) doi: 10.1073/pnas.1705378114.

  26. Dickson, A.J., Gill, B.C., Ruhl, M., Jenkyns, H.C., Porcelli, D., Idiz, E., Lyons, T.W, van den Boorn, S., Molybdenum-isotope chemostratigraphy and paleoceanography of the Toarcian Oceanic Anoxic Event (Early Jurassic).  Paleoceanography 32, 813–829 (2017) doi:10.1002/2016PA003048.

  27. Hinnov, L.A., Ruhl, M., Hesselbo, S.P., Reply to the Comment on “Astronomical constraints on the duration of the Early Jurassic Pliensbachian Stage and global climatic fluctuations” [Earth Planet. Sci. Lett. 455 (2016) 149–165].  Earth and Planetary Science Letters 481, 415–419 (2018).

  28. Scaife, J.D., Ruhl, M., Dickson, A.J., Mather, T.A., Jenkyns, H.C., Percival, L.M.E., Hesselbo, S.P., Cartwright, J., Eldrett, J.S., Bergman, S.C., Minisini, D., Sedimentary mercury enrichments as a marker for submarine Large Igneous Province volcanism? Evidence from the Mid-Cenomanian Event and Oceanic Anoxic Event 2 (Late Cretaceous).  Geochemistry, Geophysics, Geosystems18, 4253–4275 (2017). https://doi.org/10.1002/2017GC007153.

  29.  Thibault, N., Ruhl, M., Ullmann, C.V., Korte, C., Kemp, D.B., Grocke, D.R., Hesselbo, S.P., The Toarcian Oceanic Anoxic Event at Ravenscar (Yorkshire, UK) in its European context. Proceedings of the Geologists’ Association, In Press.

  30. Xu, W., Ruhl, M., Jenkyns, H.C., Huggett, J.M., Idiz, E., Leng, M.J., Minisini, D., Percival, L.M.E., Riding, J.B., Storm, M.S., Tegelaar, E.W., Tosca, N.J., Ullmann, C.V., Weijers, J.W.H., Hesselbo, S.P., Evolution of the Early Jurassic Toarcian carbon-cycle and global climatic controls on local sedimentary processes (Cardigan Bay Basin, UK).  Earth and Planetary Science Letters 484, 396–411 (2018).

  31. Xu, W., Mac Niocaill, C., Ruhl, M., Jenkyns, H.C., Riding, J.B., Hesselbo, S.P., Magnetostratigraphy of the Toarcian Stage (Lower Jurassic) of the Llanbedr (Mochras Farm) Borehole, Wales: basis for a global standard and implications for volcanic forcing of palaeoenvironmental change. Journal of the Geological Society, In Press.

  32. Korte, C., Ruhl, M., Pálfy, J., Ullmann, C.V., Hesselbo, S.P., Chemostratigraphy across the Triassic–Jurassic boundary. AGU Books, In Press.

  33. Percival, L.M.E., Jenkyns, H.C., Mather, T.A., Dickson, A.J., Batenburg, S.J., Ruhl, M., Hesselbo, S.P., Barclay, R., Jarvis, I., Robinson, S.A., Woelders, L., Does Large Igneous Province volcanism always perturb the mercury cycle? Comparing the records of Oceanic Anoxic Event 2 and the end-Cretaceous to other Mesozoic events. American Journal of Science, In Press.