TITLE: Analysis of ballast stones from the Queen Anne's Revenge by Mössbauer spectroscopy

SPEAKER: Professors Katherine Whatley^a and William Miller^b,

TIME: Thursday Sept. 19, 2002 at 4 PM

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

Mössbauer spectroscopy is being used to distinguish ballast stones of various rock types found in the reputed wreck of the Queen Anne's Revenge (QAR). The ultimate aim is to develop unique signatures of the stones to match with bedrocks of origin. The most abundant stones are tholeiitic micro-porphyritic basalt, porphyritic felsic-intermediate volcanic rocks, volcaniclastic rocks, and hornblende gabbros. Initial Mössbauer studies have concentrated on the most intense spectral line each for basalts, hornblende gabbros, and porphyritic felsic-intermediate volcanic rocks. Based on quadrupole splitting (D) and isomer shift (d) of samples analyzed, sixteen basalts consistently fell into one group, four hornblende gabbros into two groups, and four porphyritic felsic-intermediate volcanics into two groups. The ranges of the groups fell into two realms. Realm 1, (D) = 2.0-2.4 mm/s and (d) = 1.0 to 1.3 mm/s, included all basalts, three porphyritic felsic-intermediate volcanics, two altered hornblende gabbros, plus one quartz diorite. Realm 2, (D) = 2.7-2.8 mm/s and (d) = 1.1-1.2 mm/s, included two unaltered hornblende gabbros plus two granites. One volcaniclastic rock was analyzed and was found to be distinctly different with (D) = 1.2 mm/s and (d) = 0.4 mm/s. Mössbauer spectroscopy has proven an effective method of characterization for the ballast stones in conjunction with other geochemical methods. Mössbauer spectroscopy has helped place individual samples in groups (e.g. volcanics) as well as distinguish samples within groups (two hornblende gabbro groups). Dr. J. William Miller is Professor of Environmental Studies at The University of North Carolina at Asheville and is the winner of the UNCA Distinguished Teacher Award in the Natural Sciences for 2001-2002. Dr. Katherine Whatley is Dean of Faculty and Professor of Physics at The University of North Carolina at Asheville. She is a 1977 graduate of Wake Forest with a BS in Physics.