Low rare earth element concentration impact glass from the K/T Boundary at Beloc
Author(s)Fantone, Dennis W
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences.
Samuel Bowring and Asish Basu.
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This paper seeks to describe an impact glass from the K/T boundary layer at Beloc that is depleted in rare earth elements (REE) relative to continental crust. It is widely agreed that a large bolide struck the Yucatan Peninsula roughly 65 Ma spreading a worldwide iridium anomaly. However, there is only one case of a piece of the impactor being found (Kyte et al., 1995). Impact glass from the K/T boundary at Beloc, Haiti has been widely researched with several types of glass documented. So far, all of the documented glass exhibits a crustal REE compositional pattern. In this study, REE composition from two glass types from the same K/T boundary layer sample are examined using a laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS). One glass type exhibits crustal REE composition which is enriched normalized to chondrite. The other glass type, however, displays a meteoritic REE composition signature. REE patterns for this glass are nearly flat when plotted normalized to chondrite with an average La/Sm ratio of 1.51 compared to 2.69 for crustal glass. Major element data were obtained through electron microprobe analysis and displays a composition that differs from one glass type to the other. Results suggest chondritic parent material from the Chicxulub impactor.
Thesis: S.B., Massachusetts Institute of Technology, Department of Earth, Atmospheric, and Planetary Sciences, February 2011.Cataloged from PDF version of thesis. "December 20, 2010." "This thesis was submitted to the Institute Archives without all the required signatures"--Disclaimer Notice page.Includes bibliographical references (pages 33-34).
DepartmentMassachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences.
Massachusetts Institute of Technology
Earth, Atmospheric, and Planetary Sciences.