Low rare earth element concentration impact glass from the K/T Boundary at Beloc

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.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2011

Author dc:creator

• Fantone, Dennis W

Advisor dc:contributor.advisor

• Samuel Bowring and Asish Basu.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/117445

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/117445