Auxiliary Material for Paper 2010GC003438 Age systematics of two young en echelon Samoan volcanic trails Anthony A. P. Koppers College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, USA Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA Jamie A. Russell Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA Jed Roberts Department of Geosciences, Oregon State University, Corvallis, Oregon, USA Oregon Department of Geology and Mineral Industries, Portland, Oregon, USA Matthew G. Jackson Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA Department of Earth Sciences, Boston University, Boston, Massachusetts, USA Jasper G. Konter Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA Department of Geological Sciences, University of Texas at El Paso, El Paso, Texas, USA Dawn J. Wright Department of Geosciences, Oregon State University, Corvallis, Oregon, USA Hubert Staudigel Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA Stanley R. Hart Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA Koppers, A. A. P., J. A. Russell, J. Roberts, M. G. Jackson, J. G. Konter, D. J. Wright, H. Staudigel, and S. R. Hart (2011), Age systematics of two young en echelon Samoan volcanic trails, Geochem. Geophys. Geosyst., 12, Q07025, doi:10.1029/2010GC003438. Introduction: All new 40Ar/39Ar age data reported in this study have been calculated using ArArCALC v2.5 [Koppers, 2002] and their resulting *.AGE files have been included in this auxiliary material. The same files also have been saved in the standard Microsoft Excel and Adobe Acrobat formats (with the *.XLS and *.PDF extensions) and can be opened without running ArArCALC. All data files are permanently archived online in the EarthRef.org Digital Archive (ERDA) and can be downloaded by following http://earthref.org/erda/samoa-ages-koppers-2011. Note that all electronic data supplements related to this publication also can be found at EarthRef.org by selecting the http://earthref.org/err/5002 link and by following the Quick Links on that web page. The ArArCALC v2.5 software can be downloaded via the http://earthref.org/tools/ararcalc.htm link. Finally, all age data have been uploaded into the GEOCHRON Online Database at http://www.geochronportal.org/. 1. 2010gc003438-sfts01.zip Software S1. All new 40Ar/39Ar age data reported in this study have been calculated using ArArCALC v2.5 [Koppers, 2002] and their resulting *.AGE files.