Spheroids at the Cretaceous-Tertiary boundary are altered impact droplets of basaltic composition

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doi: 10.1130/0091-7613(1983)11<668:SATCBA>2.0.CO;2
Author(s): Montanari, Alessandro; Hay, Richard L.; Alvarez, Walter; Asaro, Frank; Michel, Helen V.; Alvarez, Luis W.; Smit, Jan
Author Affiliation(s): Primary:
Univ. Calif., Dep. Geol. and Geophys., Berkeley, CA, United States
Other:
Univ. Amsterdam, Netherlands
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 11(11), p.668-671. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 22 refs.; illus.
Summary: Spheroids of K-feldspar in boundary clay at Caravaca, southern Spain. Sand-size spheroids of K-feldspar, glauconite, and magnetite-quartz have been found in the C-T boundary clay in northern Italy, and spheroids of K-feldspar and pyrite were found in the boundary clay at Deep Sea Drilling Project Site 465A, in the central Pacific. Textures are similar to those of rapidly crystallized feldspar and mafic silicates. Diagenetically altered microcrystalline spherules of basaltic composition produced by the impact of a large asteroid in an ocean basin at the end of the Cretaceous. Analogous to the glassy microtektites produced by impacts on more siliceous target rocks.—Modified journal abstract.
Year of Publication: 1983
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Alkali feldspar; Basaltic composition; Caravaca Spain; Cenozoic; Clastic sediments; Clay; Cretaceous; DSDP Site 465; Deep Sea Drilling Project; Diagenesis; Europe; Feldspar group; Framework silicates; Glauconite; Hess Rise; IPOD; Iberian Peninsula; Impact features; Impacts; Italy; K-feldspar; Leg 62; Lithostratigraphy; Lower Tertiary; Magnetite; Mesozoic; Mica group; Mineral composition; Murcia Province; Murcia Spain; Murcia region; North Pacific; Northwest Pacific; Oceanography; Oxides; Pacific Ocean; Paleocene; Paleogene; Petriccio; Pyrite; Quartz; Sedimentary petrology; Sediments; Sheet silicates; Silica minerals; Silicates; Southern Europe; Spain; Spherules; Stratigraphic boundary; Stratigraphy; Sulfides; Tertiary; Textures; Upper Cretaceous; Veneto Italy; West Pacific
Coordinates: N372200 N384500 W0004000 W0022000
N453642 N453642 E0123842 E0123842
Record ID: 1983061203
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