Regional variations in spinel compositions; an important key to the Cretaceous/Tertiary event

Online Access: Get full text
doi: 10.1130/0091-7613(1986)14<485:RVISCA>2.0.CO;2
Author(s): Kyte, Frank T.; Smit, Jan
Author Affiliation(s): Primary:
Univ. Calif., Inst. Geophys. and Planet. Phys., Los Angeles, CA, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 14(6), p.485-487. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. 16 refs.; illus. incl. 1 table
Summary: Spinel, previously termed magnetite, has been identified in spherules from Cretaceous/Tertiary boundary sediments. Unlike shocked quartz, the spinels are commonly skeletal and dendritic. The spinel is distinguished from typical igneous spinel by high Mg, Al and Ni, relatively low Ti and Cr, and high Fe2O3/FeO ratio. Solid solution ranges from nearly pure magnetite to magnesioferrite and to relatively pure MgAl2O4 spinel. A regional composition is also observed: spinels from two N Pacific sites have higher Mg and Al and lower Ni and Fe than spinels from two European sites and one S Atlantic site. The most probable source of the spinel is crystallization from molten silicate droplets from a major impact event. The regional variation may provide a key to locating the impact site(s).
Year of Publication: 1986
Research Program: DSDP Deep Sea Drilling Project
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Cenozoic; Chemical composition; Composition; Cretaceous; Deep Sea Drilling Project; Europe; Impacts; Italy; Lower Tertiary; Mesozoic; Minerals; Oxides; Sedimentary rocks; Southern Europe; Spherules; Spinel; Stratigraphic boundary; Stratigraphy; Tertiary; Upper Cretaceous
Record ID: 1986052385
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom

Similar Items