Jahan Ramezani


Research Scientist
Ph.D., Washington University 1997
M.Sc., Memorial University 1993

Email: ramezani@mit.edu
Office phone: 617.253.1384
Office location: 54-1126
Administrator: Daisy M. Caban

Research interests:
Application of high-precision U-Pb geochronology to the stratigraphic record and Earth history. Calibration of the geologic timescale. Chronostratigraphy of marine and continental sedimentary basins, integrating their depositional history, biostratigraphy and records of paleoenvironmental change.


Recent publications:

Castro, M.C., Goin, F.J., Ortiz-Jaureguizar, E., Vieytes, E.C., Tsukui, K., Ramezani, J., Batezelli, A., Marsola, J.C.A., and Langer, M.C. (2018) A Late Cretaceous mammal from Brazil and the first radioisotopic age for the Bauru Group. Royal Society Open Science5, doi: 10.1098/rsos.180482.

Langer M.C., Ramezani J., and Da Rosa Á.A.S. (in press) U-Pb age constraints on dinosaur rise from south Brazil. Gondwana Research, 10.1016/j.gr.2018.01.005, doi: https://doi.org/10.1016/j.gr.2018.01.005.

Heimdal T.H., Svensen H.H., Ramezani J., Iyer K., Pereira E., Rodrigues R., Jones M.T., and Callegaro S. (2018) Large-scale sill emplacement in Brazil as a trigger for the end-Triassic crisis. Scientific Reports, 8(1), doi: https://doi.org/10.1038/s41598-017-18629-8.

Lockley M.G., Houck K.J., Matthews N., McCrea R.T., Xing L., Tsukui K., Ramezani J., Breithaupt B., Cart K., Martin J., Buckley L.G., and Hadden G. (2018) New theropod display arena sites in the Cretaceous of North America: Clues to distributions in space and time. Cretaceous Research, 81(Supplement C), 9-25, doi: https://doi.org/10.1016/j.cretres.2017.09.009.

Carballido J.L., Pol D., Otero A., Cerda I.A., Salgado L., Garrido A.C., Ramezani J., Cuneo N.R., and Krause J.M. (2017) A new giant titanosaur sheds light on body mass evolution among sauropod dinosaurs. Proceedings of the Royal Society B-Biological Sciences, 284(1860), doi: https://doi.org/10.1098/Rspb.2017.1219.

Fairchild L.M., Swanson-Hysell N.L., Ramezani J., Sprain C.J., and Bowring S.A. (2017) The end of Midcontinent Rift magmatism and the paleogeography of Laurentia. Lithosphere, 9(1), 117-133, doi: https://doi.org/10.1130/L580.1.

Ramezani J., and Bowring S.A. (2017) Advances in numerical calibration of the Permian timescale based on radioisotopic geochronology. In: Lucas, S.G., Shen, S.Z. (Eds.), The Permian Timescale. Geological Society Special Publications SP450, London,doi: https://doi.org/10.1144/sp450.17.

Wu Q., Ramezani J., Zhang H., Wang T.T., Yuan D.X., Mu L., Zhang Y.C., Li X.H., and Shen S.Z. (2017) Calibrating the Guadalupian Series (Middle Permian) of South China. Palaeogeography Palaeoclimatology Palaeoecology, 466, 361-372, doi: https://doi.org/10.1016/j.palaeo.2016.11.011.

Bold U., Smith E.F., Rooney A.D., Bowring S.A., Buchwaldt R., Dudas F.O., Ramezani J., Crowley J.L., Schrag D.P., and Macdonald F.A. (2016) Neoproterozoic Stratigraphy of the Zavkhan Terrane of Mongolia: The Backbone for Cryogenian and Early Ediacaran Chemostratigraphic Records. American Journal of Science, 316(1), 1-63, doi: https://doi.org/10.2475/01.2016.01.

Chu Z., He H., Ramezani J., Bowring S.A., Hu D., Zhang L., Zheng S., Wang X., Zhou Z., Deng C., and Guo J. (2016) High-precision U-Pb geochronology of the Jurassic Yanliao Biota from Jianchang (western Liaoning Province, China): Age constraints on the rise of feathered dinosaurs and eutherian mammals. Geochemistry, Geophysics, Geosystems, 10.1002/2016GC006529, doi: https://doi.org/10.1002/2016GC006529.

Clyde W.C., Ramezani J., Johnson K.R., Bowring S.A., and Jones M.M. (2016) Direct high-precision U–Pb geochronology of the end-Cretaceous extinction and calibration of Paleocene astronomical timescales. Earth and Planetary Science Letters, 452, 272-280, doi: https://doi.org/10.1016/j.epsl.2016.07.041.

Pu J.P., Bowring S.A., Ramezani J., Myrow P., Raub T.D., Landing E., Mills A., Hodgin E., and Macdonald F.A. (2016) Dodging snowballs: Geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota. Geology, 44(11), 955-958, doi: https://doi.org/10.1130/G38284.1.

Turnbull R., Tulloch A., Ramezani J., and Jongens R. (2016) Extension-facilitated pulsed S-I-A-type “flare-up” magmatism at 370 Ma along the southeast Gondwana margin in New Zealand: Insights from U-Pb geochronology and geochemistry. Geological Society of America Bulletin, 128(9-10), 1500-1520, doi: https://doi.org/10.1130/b31426.1.

Wang T., Ramezani J., Wang C., Wu H., He H., and Bowring S.A. (2016) High-precision U–Pb geochronologic constraints on the Late Cretaceous terrestrial cyclostratigraphy and geomagnetic polarity from the Songliao Basin, Northeast China. Earth and Planetary Science Letters, 446, 37-44, doi: https://doi.org/10.1016/j.epsl.2016.04.007.

Day M.O., Ramezani J., Bowring S.A., Sadler P.M., Erwin D.H., Abdala F., and Rubidge B.S. (2015) When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa. Proceedings of the Royal Society B-Biological Sciences, 282(1811), doi: https://doi.org/10.1098/Rspb.2015.0834.

Eldrett J.S., Ma C., Bergman S.C., Lutz B., Gregory F.J., Dodsworth P., Phipps M., Hardas P., Minisini D., Ozkan A., Ramezani J., Bowring S.A., Kamo S.L., Ferguson K., Macaulay C., and Kelly A.E. (2015) An astronomically calibrated stratigraphy of the Cenomanian, Turonian and earliest Coniacian from the Cretaceous Western Interior Seaway, USA: Implications for global chronostratigraphy. Cretaceous Research, 56, 316-344, doi: https://doi.org/10.1016/j.cretres.2015.04.010.

Lehrmann D.J., Stepchinski L., Altiner D., Orchard M.J., Montgomery P., Enos P., Ellwood B.B., Bowring S.A., Ramezani J., Wang H.M., Wei J.Y., Yu M.Y., Griffiths J.D., Minzoni M., Schaal E.K., Li X.W., Meyer K.M., and Payne J.L. (2015) An integrated biostratigraphy (conodonts and foraminifers) and chronostratigraphy (paleomagnetic reversals, magnetic susceptibility, elemental chemistry, carbon isotopes and geochronology) for the Permian-Upper Triassic strata of Guandao section, Nanpanjiang Basin, south China. Journal of Asian Earth Sciences, 108, 117-135, doi: https://doi.org/10.1016/j.jseaes.2015.04.030.

Machlus M.L., Ramezani J., Bowring S.A., Hemming S.R., Tsukui K., and Clyde W.C. (2015) A strategy for cross-calibrating U–Pb chronology and astrochronology of sedimentary sequences: An example from the Green River Formation, Wyoming, USA. Earth and Planetary Science Letters, 413(0), 70-78, doi: https://doi.org/10.1016/j.epsl.2014.12.009.

Weiss B.P., Maloof A.C., Tailby N., Ramezani J., Fu R.R., Hanus V., Trail D., Bruce Watson E., Harrison T.M., Bowring S.A., Kirschvink J.L., Swanson-Hysell N.L., and Coe R.S. (2015) Pervasive remagnetization of detrital zircon host rocks in the Jack Hills, Western Australia and implications for records of the early geodynamo. Earth and Planetary Science Letters, 430, 115-128, doi: https://doi.org/10.1016/j.epsl.2015.07.067.

Langer M.C., Rincón A.D., Ramezani J., Solórzano A., and Rauhut O.W.M. (2014) New dinosaur (Theropoda, stem-Averostra) from the earliest Jurassic of the La Quinta formation, Venezuelan Andes. Royal Society Open Science, 1(2), 140184, doi: https://doi.org/10.1098/rsos.140184.

Ramezani J., Fastovsky D.E., and Bowring S.A. (2014) Revised chronostratigraphy of the Lower Chinle Formation strata in Arizona and New Mexico (USA): High-precision U-Pb geochronological constraints on the Late Triassic evolution of dinosaurs. American Journal of Science, 314(6), 981-1008, doi: https://doi.org/10.2475/06.2014.01.

Thompson M.D., Ramezani J., and Crowley J.L. (2014) U-Pb zircon geochronology of Roxbury Conglomerate, Boston Basin, Massachusetts: Tectono-stratigraphic implications for Avalonia in and beyond SE New England. American Journal of Science, 314(6), 1009-1040, doi: https://doi.org/10.2475/06.2014.02.

Atchley S.C., Nordt L.C., Dworkin S.I., Ramezani J., Parker W.G., Ash S.R., and Bowring S.A. (2013) A Linkage Among Pangean Tectonism, Cyclic Alluviation, Climate Change, and Biologic Turnover In the Late Triassic: The Record From The Chinle Formation, Southwestern United States. Journal of Sedimentary Research, 83(12), 1147-1161, doi: https://doi.org/10.2110/jsr.2013.89.

Cosentino D., Buchwaldt R., Sampalmieri G., Iadanza A., Cipollari P., Schildgen T.F., Hinnov L.A., Ramezani J., and Bowring S.A. (2013) Refining the Mediterranean “Messinian gap” with high-precision U-Pb zircon geochronology, central and northern Italy. Geology, 41(3), 323-326, doi: https://doi.org/10.1130/g33820.1.

Cúneo R., Ramezani J., Scasso R., Pol D., Escapa I., Zavattieri A.M., and Bowring S.A. (2013) High-precision U–Pb geochronology and a new chronostratigraphy for the Cañadón Asfalto Basin, Chubut, central Patagonia: Implications for terrestrial faunal and floral evolution in Jurassic. Gondwana Research, 24(3), 1267-1275, doi: https://doi.org/10.1016/j.gr.2013.01.010.

Myrow P.M., Ramezani J., Hanson A.E., Bowring S.A., Racki G., and Rakociński M. (2013) High-precision U–Pb age and duration of the latest Devonian (Famennian) Hangenberg event, and its implications. Terra Nova, 10.1111/ter.12090, n/a-n/a, doi: https://doi.org/10.1111/ter.12090.

Rubidge B.S., Erwin D.H., Ramezani J., Bowring S.A., and de Klerk W.J. (2013) High-precision temporal calibration of Late Permian vertebrate biostratigraphy: U-Pb zircon constraints from the Karoo Supergroup, South Africa. Geology, 41(3), 363-366, doi: https://doi.org/10.1130/G33622.1.

Turnbull R.E., Tulloch A.J., and Ramezani J. (2013) Zetland Diorite, Karamea Batholith, west Nelson: field relationships, geochemistry and geochronology demonstrate links to the Carboniferous Tobin Suite. New Zealand Journal of Geology and Geophysics, 10.1080/00288306.2013.775166, 1-17, doi: https://doi.org/10.1080/00288306.2013.775166.

Mietto P., Manfrin S., Preto N., Rigo M., Roghi G., Furin S., Gianolla P., Posenato R., Muttoni G., Nicora A., Buratti N., Cirilli S., Spoetl C., Ramezani J., and Bowring S.A. (2012) The Global Boundary Stratotype Section and Point (GSSP) of the Carnian stage (Late Triassic) at Prati di Stuores/Stuores Wiesen section (Southern Alps, NE Italy). Episodes, 35(3), 414-430, doi.

Ramezani J., Hoke G.D., Fastovsky D.E., Bowring S.A., Therrien F., Dworkin S.I., Atchley S.C., and Nordt L.C. (2011) High-precision U-Pb zircon geochronology of the Late Triassic Chinle Formation, Petrified Forest National Park (Arizona, USA): Temporal constraints on the early evolution of dinosaurs. Geological Society of America Bulletin, 123(11-12), 2142-2159, doi: https://doi.org/10.1130/b30433.1.

Shen S.-z., Crowley J.L., Wang Y., Bowring S.A., Erwin D.H., Sadler P.M., Cao C.-q., Rothman D.H., Henderson C.M., Ramezani J., Zhang H., Shen Y., Wang X.-d., Wang W., Mu L., Li W.-z., Tang Y.-g., Liu X.-l., Liu L.-j., Zeng Y., Jiang Y.-f., and Jin Y.-g. (2011) Calibrating the End-Permian Mass Extinction. Science, 334(6061), 1367-1372, doi: https://doi.org/10.1126/science.1213454.

van Soest M.C., Hodges K.V., Wartho J.-A., Biren M.B., Monteleone B.D., Ramezani J., Spray J.G., and Thompson L.M. (2011) (U-Th)/He dating of terrestrial impact structures: The Manicouagan example. Geochem. Geophys. Geosyst., 12, Q0AA16, doi.

Maloof A.C., Ramezani J., Bowring S.A., Fike D.A., Porter S.M., and Mazouad M. (2010) Constraints on early Cambrian carbon cycling from the duration of the Nemakit-Daldynian–Tommotian boundary δ13C shift, Morocco. Geology, 38(7), 623-626, doi: https://doi.org/10.1130/g30726.1.