Gerta Keller

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Gerta Keller , born as Gertrud Keller (born March 7, 1945 in Schaan , Liechtenstein ), is an American geologist , paleontologist and professor at Princeton University . She is known as a proponent of the thesis that the mass extinction on the Cretaceous-Paleogene border was the result of the Dekkan-Trapp volcanism and not an asteroid impact in the Chicxulub crater (Alvarez hypothesis).

Life

Keller went to school in Switzerland and was a seamstress, traveling through England, North Africa and Spain to Australia in the 1960s. In 1965 she emigrated to Australia, in 1968 she went to the USA. She studied geology and paleontology from San Francisco State University with a bachelor's degree in 1974 (in anthropology and geology) and received her PhD from Stanford University in 1978 . Before that she worked for the US Geological Survey. From 1984 she was Associate Professor and from 1992 Professor of Geology at Princeton. Her specialty was marine foraminifera studies for the reconstruction of climate changes in the last 100 million years, whereby she began her research with the neogene at the end of the 1970s and then gradually examined older formations.

In particular from 2003 she emerged as a critic of the Alvarez hypothesis of mass extinction on the Cretaceous-Paleogene border, which she rejects. She found layers in which the iridium-rich clay layers (used by Alvarez as an indicator of an asteroid impact) and the tektites or quartz with the signature of an impact shock wave with sediments up to 2 m thick are separated. Supporters of the Alvarez thesis interpreted this as a tsunami deposit, but according to Keller, the deposit took place over a longer period of up to 300,000 years. In addition, she claims to have found signs of at least three meteorite impacts separated by longer periods of time during the period in question. Instead, she prefers flood basalts and volcanism in the Deccan traps in India and their climatic consequences as causes, which began 250,000 years before the meteorite impact, but some of its main activities were during the mass extinction, as she and colleagues discovered.

She represented her theses in the BBC Horizon program What didn´t kill the dinosaurs (2004) and in First Apocalypse (2008) on the History Channel. She worked in this area with Wolfgang Stinnesbeck (professor in Heidelberg) and Thierry Adatte (professor in Lausanne).

Keller's assumptions with regard to the chronological classification of the Chicxulub impact found a mixed echo in the specialist literature and are considered unlikely in view of new dating and research results.

Keller holds the citizenships of Liechtenstein, Switzerland and the USA.

Fonts

  • WC Ward, G. Keller, W. Stinnesbeck, T. Adatte: Yucatán subsurface stratigraphy: Implications and constraints for the Chicxulub impact. Geology 23, 1995, pp. 873-876
  • with N. McLeod (Editor): Cretaceous-Tertiary Mass Extinctions: Biotic and Environmental Changes. WW Norton 1996
  • G. Keller, T. Adatte, W. Stinnesbeck, Rebolledo-Vieyra, J. U: Fucugauchi, U. Kramar, D. Stueben: Chicxulub impact predates the KT boundary mass extinction. Proc. Nat. Acad. Sci. USA, 101, 2004, pp. 3753-3758
  • Impact stratigraphy: Old principle, new reality. GSA Special Papers 437, 2007, pp. 147-178
  • Gerta Keller, Thierry Adatte, Zsolt Berner, Markus Harting, Gerald Baum, Michael Prauss, Abdel Tantawy, Doris Stueben: Chicxulub impact predates K – T boundary: New evidence from Brazos, Texas. Earth and Planetary Science Letters 255, 2007, pp. 339-356
  • G. Keller, S. Abramovich, Z. Berner, T. Adatte: Biotic effects of the Chicxulub impact, K – T catastrophe and sea level change in Texas. Palaeogeography, Palaeoclimatology, Palaeoecology 271, 2009, pp. 52-68.
  • Gerta Keller, Thierry Adatte, Alfonso Pardo Juez, Jose G. Lopez-Oliva: New evidence concerning the age and biotic effects of the Chicxulub impact in NE Mexico. Journal of the Geological Society 166, 2009, pp. 393-411.

Web links

Individual evidence

  1. ↑ Steven Schultz, Dinosaur dust-up: Princeton paleontologist produces evidence for new theory on extinction , Princeton Weekly Bulletin, September 22, 2003
  2. ^ Gerta Keller, W. Stinnesbeck, T. Adatte, D. Stueben: "Multiple impacts across the Cretaceous-Tertiary boundary". Earth-Science Reviews 62, 2003, pp. 327-363
  3. ↑ Blair Schoene, Kyle M. Samperton, Michael P. Eddy, Gerta Keller, Thierry Adatte, Samuel A. Bowring, Syed FR Khadri & Brian Gertsch: U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction, Science 347, 2015, 182-184, from uranium-lead dating in zirconia.
  4. Jump up ↑ Gerta Keller, T. Adatte, S. Gardin, A. Bartolini, S. Bajpai: Main Deccan volcanism phase ends near the K – T boundary : Evidence from the Krishna – Godavari Basin, SE India, Earth and Planetary Science Letters 268, 2008, pp. 293-311
  5. ↑ Peter Schulte: Comment on the paper "Chicxulub impact predates KT boundary: New evidence from Brazos, Texas" by Keller et al. (2007) . (PDF) In: Earth and Planetary Science Letters . No. 269, May 2008, pp. 614-620. doi : 10.1016 / j.epsl.2007.11.066 .
  6. ^ Paul R. Renne, Alan L. Deino, Frederik J. Hilgen, Klaudia F. Kuiper, Darren F. Mark, William S. Mitchell III, Leah E. Morgan, Roland Mundil, Jan Smit: Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary . (PDF) In: Science . 339, No. 6120, February 2013, pp. 684-687. doi : 10.1126 / science.1230492 .
  7. ↑ Johan Vellekoop, Appy Sluijs, Jan Smit, Stefan Schouten, Johan WH Weijers, Jaap S. Sinninghe Damsté, Henk Brinkhuis: Rapid short-term cooling Following the Chicxulub impact at the Cretaceous-Paleogene boundary . In: pnas . 111, No. 21, May 2014. doi : 10.1073 / pnas.1319253111 .
personal data
SURNAME Keller, Gerta
ALTERNATIVE NAMES Keller, Gertrud (maiden name); Majda, Gerta (married name)
BRIEF DESCRIPTION American geologist and paleontologist
DATE OF BIRTH March 7, 1945
PLACE OF BIRTH Schaan , Liechtenstein