Phone: 979.845.0506
Fax: 979.845.0876
geldmacher@iodp.tamu.edu

Integrated Ocean Drilling Program
1000 Discovery Drive
College Station, TX, 77845-9547

Dr. Jörg Geldmacher

Adjunct Professor/IODP Staff Scientist

Ph.D., University of Kiel/Germany, 2000

Research specialty: igneous geochemistry

Research

  • Igneous geochemistry and geochronology (including radiogenic isotope geochemistry and 40Ar/39Ar age dating)
  • Geochemistry of volcanic rocks and the composition of the Earth’s mantle
  • Evolution of marine intraplate volcanism (including Large Igneous Provinces) and plate tectonic reconstructions
  • Hydrothermal and low-temperature alteration of oceanic crust

Recent Projects

  • Origin and impact of volcanism in the eastern North Atlantic
  • Age and Geochemistry of igneous rocks in the Guatemalan forearc: Implications for the early history of the Caribbean Large Igneous Province
  • U-Th-Pb, Nd and Hf isotopic investigation of a complete in situ section of upper oceanic crust formed at a superfast spreading ridge (IODP Site 1256D)

Publications

  • Geldmacher J., Hoernle K., Bogaard P.v.d., Hauff F., Klügel A. Age and geochemistry of the Central American forearc basement (DSDP Leg 67 and 84): Insights into Mesozoic arc volcanism and seamount accretion. Journal of Petrology (in review)
  • Duggen S., Hoernle K., Klügel A., Geldmacher J., Thirlwall M., Hauff F., Lowry D., Oates N. Geochemical zonation of the Miocene Alboran basin volcanism (westernmost Mediterranean): Geodynamic implications. Contributions to Mineralogy and Petrology (accepted)
  • Geldmacher J., Hoernle K., Klügel A., Bogaard P.v.d., Bindeman I. (2008) Geochemistry of a new enriched mantle type locality in the northern hemisphere: Implications for the origin of the EM-I source. Earth and Planetary Sciences Letters 265, 167-182
  • Geldmacher J., Hoernle K., Klügel A., Bogaard P.v.d., Wombacher F., Berning B. (2006) Origin and geochemical evolution of the Madeira-Tore Rise (eastern North Atlantic). Journal of Geophysical Research 111, B09206, doi: 10.1029/2005JB003931
  • Wilson D. S., et al. (2006) Drilling gabbro in intact ocean crust formed at the East Pacific Rise. Science 312, 1016-1020
  • Geldmacher J., Hoernle K., Klügel A., Bogaard P.v.d., Duggen S. (2006) A geochemical transect across a heterogeneous mantle upwelling: implications for the evolution of the Madeira hotspot in space and time. Lithos 90, 131-144
  • Geldmacher J., Hoernle K., Bogaard P.v.d., Duggen S., Werner R. (2005) New 40Ar/39Ar age and geochemical data from seamounts in the Canary and Madeira volcanic province: Support for the mantle plume hypothesis. Earth and Planetary Science Letters 237, 85-101
  • Klügel A., Walter T.R., Schwarz S., Geldmacher J. (2005) Gravitative spreading causes en-echelon diking along a rift zone of Madeira archipelago: An experimental approach and implications for magma transport. Bulletin of Volcanology 68, 37-46
  • Schwarz S., Klügel A., Bogaard P.v.d., Geldmacher J. (2005) Internal structure of a volcanic rift system in the eastern North Atlantic: The Desertas rift zone, Madeira archipelago. Journal of Volcanology and Geothermal Research 141, 123-155
  • Geldmacher J., Hanan B.B., Blichert-Toft J., Harpp K., Hoernle K., Hauff F., Werner R., Kerr A. (2003) Hf isotopic variations in volcanic rocks from the Caribbean Large Igneous Province and Galápagos hotspot tracks. Geochemistry, Geophysics, Geosystems, Vol. 4, No. 7, 2002GC000477
  • Geldmacher J., Troll V.R., Emeleus C.H., Donaldson C.H. (2002) Pb-isotope evidence for contrasting crustal contamination of primitive to evolved magmas from Ardnamurchan and Rum: implications for the structure of the underlying crust. Scottish Journal of Geology 38, 55-61
  • Geldmacher J., Hoernle K., Bogaard P.v.d., Zankl G., Garbe-Schönberg D. (2001) Earlier history of the ? 70 Ma old Canary Hotspot based on the temporal and geochemical evolution of the Selvagen Archipelago and neighboring seamounts in the eastern North Atlantic. Journal of Volcanology and Geothermal Research 111, 55-87
  • Geldmacher J., Hoernle K. (2000) The 72 Ma Geochemical Evolution of the Madeira Hotspot (eastern North Atlantic): Recycling of Palaeozoic (? 500 Ma) Basaltic and Gabbroic Crust. Earth and Planetary Science Letters 183, 73-92, Corrigendum in 186, 333 (2001)
  • Geldmacher J., Bogaard P.v.d., Hoernle K., Schmincke H.-U. (2000) New 40Ar/39Ar dating of the Madeira archipelago and hotspot track (eastern North Atlantic). Geochemistry, Geophysics, Geosystems, Vol. 1 No.1, 1999GC000018
  • Geldmacher J., Haase K.M., Devey C.W., Garbe-Schönberg D. (1998) The petrogenesis of Tertiary cone-sheets in Ardnamurchan, NW Scotland: petrological and geochemical constraints on crustal contamination and partial melting. Contributions to Mineralogy and Petrology 131, 196-209

Affiliations

  • American Geophysical Union
  • Deutsche Mineralogische Gesellschaft
  • Deep Crust and Mantle Dynamics Group (Geology and Geophysics Department, TAMU)

Links