Rocky Mountain - 55th Annual Meeting (May 7-9, 2003)
Paper No. 1-10
Presentation Time: 11:05 AM-11:20 AM

METALLIC/MAGNETIC MICROSPHERULES: EVIDENCE SUPPORTING AN IMPACT EVENT HORIZON IN THE BLACK DRAGON MEMBER OF THE MOENKOPI FORMATION, SAN RAFAEL SWELL, UTAH

FANDRICH, J.W., Westwater Group Geological Research Facility, 586 W. Indian Creek Drive, #1, Grand Junction, CO 81501, westwaterranch@juno.com and DUJAY, Richard C., Mesa State College Center for Microscopy

Microspherules ranging in size from 18µm to 44µm have been discovered in breccia at the base of the Black Dragon member of the Moenkopi formation, San Rafael Swell, Utah. These particles and the breccia in which they are found suggest the presence of a bolide impact event horizon in the Black Dragon. This unit is currently considered to be lower Triassic age; however, the apparent lack of fossils in this unit makes dating difficult.

The morphology and chemistry of these microspherules has been studied employing a scanning electron microscope (SEM) with energy dispersive spectrometry (EDS). The results of the SEM/EDS research appears consistent with bolide impact as a generator of these particles.

Rocky Mountain - 55th Annual Meeting (May 7-9, 2003)
General Information for this Meeting
Session No. 1
Tectonics/Structural Geology, Stratigraphy/Coal Geology, Petrology, Planetary Geology
Fort Lewis College: Noble Hall 125
8:30 AM-11:20 AM, Wednesday, May 7, 2003

Geological Society of America Abstracts with Programs, Vol. 35, No. 5, April 2003, p. 4

© Copyright 2003 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.