H. C. Jenkyns
Lecturer in Geology
My research is concerned primarily with the palaeoceanography and palaeoclimatology of Jurassic and Cretaceous marine sediments. Areas of study include northern and southern Europe and the Pacific Ocean. My approach has been to elucidate the causality of major global events in Earth history by examining their sedimentary and geochemical records. To this end, I have studied the distribution, in time and space, of sediments unusually rich in organic carbon as well as the stratigraphic distribution of oxygen, carbon, nitrogen and strontium isotopes in rocks and fossils. I am also interested in the preservation of climatic signals in marine and continental sediments. Specific research topics include the causes and consequences of Oceanic Anoxic Events, particularly those of the early Toarcian (183Ma), the early Aptian (120Ma) and the Cenomanian-Turonian boundary (93Ma). This latter interval was apparently characterized by the highest global palaeotemperatures of the last 115Ma, represented a huge disturbance of the carbon cycle, and was a major turning point in the climatic history of the Earth. I have also been involved in a multidisciplinary study of the type Kimmeridge Clay, through the Kimmeridge Drilling Project. I have recently been investigating the origin of north Pacific guyots - drowned carbonate platforms capping volcanic seamounts - which we believe were formed as a result of suppression of shallow-water carbonate production as northward plate movement pushed the edifices into peri-equatorial waters whose surface temperatures were >30 degrees C. Tropical waters were simply too hot for many carbonate-secreting organisms to survive. Platform drowning can thus be related to the thermal maximum of the mid- to Late Cretaceous greenhouse earth. Cretaceous palaeoclimates in high latitudes are another interest, with the postulated high temperatures - at times in excess of 20 degrees C - posing a fundamental problem in understanding how heat was transported across the globe. Currently I am exploring the use of novel isotope systems (Fe, S, Cr) in Mesozoic palaeoceanography.
- Jenkyns H.C. and Wilson, P.A., 1999. Stratigraphy, paleoceanography and evolution of Cretaceous Pacific guyots: relics from a greenhouse earth. Am. J. Sci., 299, 341-392.
- Weedon, G.P and Jenkyns, H.C., 1999. Cyclostratigraphy and the Early Jurassic time scale: data from the Belemnite Marls, Dorset, southern England. Bull. Geol. Soc. Am., 111, 1823-1840.
- Jones, C.E. and Jenkyns, H.C., 2001. Seawater strontium isotopes, oceanic anoxic events, and seafloor hydrothermal activity in the Jurassic and Cretaceous Am.J. Sci., 111, 112-149.
- Morgans-Bell, H.S., Coe, A.L., Hesselbo, S.P., Jenkyns, H.C., Weedon, G.P., Marshall, J.E.A., Tyson, R.V. and Williams, C.J., 2001. Integrated stratigraphy of the Kimmeridge Clay Formation (Upper Jurassic) based on exposures and boreholes in south Dorset, UK. Geol. Mag., 138, 511-539.
- Jenkyns, H.C., Gröcke, D.R.and Hesselbo, S.P., 2001. Nitrogen isotope evidence for water mass denitrification during the early Toarcian Oceanic Anoxic Event. Paleoceanography, 16, 593-603.
- Jenkyns, H.C., Jones, C.E., Gröcke, D.R., Hesselbo, S.P. and Parkinson, D.N., 2002. Chemostratigraphy of the Jurassic System: applications, limitations and implications for palaeoceanography. J. Geol. Soc. Lond., 159, 351-378.
- Jenkyns, H.C., 2003. Evidence for rapid climate change in the Mesozoic-Palaeogene greenhouse world. Phil. Trans. R. Soc., Series A, 361, 1885-1916.
- Wall, G.R. and Jenkyns, H.C., 2004. The age, origin and tectonic significance of Mesozoic sediment-filled fissures in the Mendip Hills (south-west England): implications for extension models and Jurassic sea-level curves. Geol. Mag., 141, 471-504.
- Luciani, V., Cobianchi, M. and Jenkyns, H.C. 2004. Albian high-resolution biostratigraphy and isotope stratigraphy: the Coppa della Nuvola pelagic succession of the Gargano Promontory (Southern Italy). Eclog. Geol. Helv., 97, 77-92.
- Tsikos, H., Jenkyns, H.C., Walsworth-Bell, B., Petrizzo, M.R. , Forster, A., Kolonic, S., Erba, E., Premoli Silva, I., Baas, M., Wagner, T., and Sinninghe Damsté, J.S., 2004. Carbon-isotope stratigraphy recorded by the Cenomanian–Turonian Oceanic Anoxic Event: correlation and implications based on three key localities. J. Geol. Soc. Lond., 161, 711-719.
- Pancost, R.D., Crawford, N., Magness, S,, Turner, A., Jenkyns, H.C. and Maxwell, J.R., 2004. Further evidence for the development of photic-zone euxinic conditions during Mesozoic Oceanic Anoxic Events. J. Geol. Soc. Lond., 161, 353-364.
- Matthews, A., Morgans-Bell, H.S., Emmanuel, S., Jenkyns, H.C., Erel, Y. and Halicz, L., 2004. Controls on iron-isotope fractionation in organic-rich sediments (Kimmeridge Clay, Upper Jurassic, southern England). Geochim. Cosmochim. Acta, 68, 3107-3123.
- Tsikos, H., Karakitsios, V., Van Breugel, Y., Walsworth-Bell, B., Bombardiere, L., Petrizzo, M.R., Sinninghe Damsté, J.S., Schouten, S., Erba, E., Premoli Silva, I., Farrimond, P., Tyson, R.V., and Jenkyns, H.C., 2004. Organic-carbon deposition in the Cretaceous of the Ionian Basin, NW Greece: the Paquier Event (OAE 1b) revisited. Geol. Mag., 141, 401-416.
- Jenkyns, H.C., Forster, A., Schouten, S. and Sinninghe Damsté, J.S., 2004. High temperatures in the Late Cretaceous Arctic Ocean. Nature, 432, 888-892.
- Li, X., Jenkyns, H.C., Wang, C., Hu, X., Chen, X., Wei, Y., Huang, Y. and Cui, J., 2006. Upper Cretaceous carbon- and oxygen-isotope stratigraphy of hemipelagic carbonate facies from southern Tibet, China. J. Geol. Soc. Lond., 163, 375-382.
- Jarvis, I., Gale, A.S., Jenkyns, H.C. and Pearce, M.A., 2006. Secular variation in Late Cretaceous carbon isotopes: a new δ13C reference curve for the Cenomanian–Santonian (99.6–83.5 Ma). Geol. Mag., 143, 561-608.
- Hesselbo, S.P., Jenkyns, H.C., Duarte, L.V. and Oliveira, L.C.V., 2007. Carbon-isotope record of the early Jurassic (Toarcian) Oceanic Anoxic Event from fossil wood and marine carbonate (Lusitanian Basin, Portugal). Earth planet. Sci. Letts, 253, 455-470.
- Karakitsios, V., Tsikos, H., van Breugel, Y., Koletti, L., Sinninghe Damsté, J.S. and Jenkyns, H.C., 2007. First evidence for the Cenomanian-Turonian Oceanic Anoxic Event (OAE2, 'Bonarelli' Event) from the Ionian Zone, western continental Greece. Int. J. Earth Sci., 96, 343-352.
- Jenkyns, H.C., Matthews, A., Tsikos, H. and Erel, Y., 2007. Nitrate reduction, sulfate reduction, and sedimentary iron isotope evolution during the Cenomanian-Turonian Oceanic Anoxic Event. Paleoceanography, 22, PA3208, doi:10.1029/2006PA001355.
- Woodfine, R.G., Jenkyns, H. C., Sarti, M., Baroncini, F. and Violante, C., 2008. The response of two Tethyan carbonate platforms to the early Toarcian oceanic anoxic event: environmental change and differential subsidence. Sedimentology, 55, 1011-1028.
- Scopelliti, G., Bellanca, A., Erba, E., Jenkyns, H.C., Neri, R., Tamagnini, P., Luciani, V. and Masetti, D., 2008. Cenomanian-Turonian carbonate and organic-carbon isotope records, biostratigraphy and provenance of a key section in NE Sicily, Italy: Palaeoceanographic and palaeogeographic implications. Palaeogeogr. Palaeoclimatol. Palaeoecol., 265, 59-77.
- Parente, M., Frijia, J., Di Lucia, M., Jenkyns, H.C., Woodfine, R.G. and Baroncini, F., 2008. Stepwise extinction of larger foraminifers at the Cenomanian-Turonian boundary: A shallow-water perspective on nutrient fluctuations during Oceanic Anoxic Event 2 (Bonarelli Event). Geology, 36, 715-718.