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⁴⁰Ar/³⁹Ar Data for White Mica, Biotite, and K-Feldspar Samples from Low-Grade Metamorphic Rocks in the Westminster Terrane and Adjacent Rocks, Maryland

Michael J. Kunk and Ryan McAleer

PDF (1.31 MB)

Introduction

This report contains reduced ⁴⁰Ar/³⁹Ar data of white mica and K-feldspar mineral separates and matrix of a whole rock phyllite, all from low-grade metamorphic rocks of the Westminster terrane and adjacent strata in central Maryland. This report presents these data in a preliminary form, but in more detail than can be accommodated in todays professional journals. Also included in this report is information on the location of the samples and a brief description of the samples. The data contained herein are not interpreted in a geological context, and care should be taken by readers unfamiliar with argon isotopic data in the use of these results; many of the individual apparent ages are not geologically meaningful. This report is primarily a detailed source document for subsequent publications that will integrate these data into a geological context.

For more information, please contact author.

Suggested citation:
Kunk, M.J., and McAleer, Ryan, 2008, 40Ar/39Ar data for white mica, biotite, and k-feldspar samples from low-grade metamorphic rocks in the Westminster terrane and adjacent rocks, Maryland: U.S. Geological Survey Open-File Report 2008–1281, 27 p., available only online at https://pubs.usgs.gov/of/2008/1281.

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