Martinez-Ruiz, F.; Ortega-Huertas, M.; Palomo-Delgado, I.; Smit, J. (2001): K-T boundary spherules from Blake Nose (ODP Leg 171B) as a record of the Chicxulub ejecta deposits. Geological Society of London, London, United Kingdom, In: Kroon, Dick (editor), Norris, Richard D. (editor), Klaus, A. (editor), Western North Atlantic Palaeogene and Cretaceous palaeoceanography, 183, 149-161, georefid:2001-079994

Abstract:
The Cretaceous-Tertiary (K-T) boundary interval recovered by the ODP Leg 171 at Site 1049 (Blake Nose, NW Atlantic) contains a thick (9-17 cm) spherule bed marking the boundary. The spherules are mainly perfect spheres with a lesser proportion of oval spherules. They usually range from 100 to 1000 mu m. This bed represent the diagenetically altered impact ejecta from Chicxulub and further supports this structure as the site of the K-T impact. Mineralogical and geochemical investigations indicate that impact-generated glass was altered to smectite. Transmission electron microscopy observations revealed in some spherules that smectite is forming from a Si-rich or Ca-rich material, which could suggest a precursor similar to Haitian glasses. The variable thickness and the presence of some Cretaceous planktonic foraminifera and clasts of Cretaceous chalk suggest reworking of the ejecta material. However, the spherule bed confirms that a large volume of the Chicxulub ejecta material reached the Blake Nose Plateau.
Coverage:
West: -76.3800 East: -76.0600 North: 30.0900 South: 29.5500
Relations:
Expedition: 171A
Site: 171A-1049
Expedition: 171B
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=2001-079994 (c.f. for more detailed metadata)
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