caa a22 4500 477062393 CHVBK 20180405111404.0 cr unu---uuuuu 170330e19960901xx s 000 0 eng 10.1007/s004450050123 doi (NATIONALLICENCE)springer-10.1007/s004450050123 Sourcing and identifying andesitic tephras using major oxide titanomagnetite and hornblende chemistry, Egmont volcano and Tongariro Volcanic Centre, New Zealand [Elektronische Daten] [S. J. Cronin, R. C. Wallace, V. E. Neall]  Canonical discriminant function analysis was employed to discriminate between electron microprobe-determined titanomagnetite and hornblende analyses from Egmont volcano and Tongariro Volcanic Centre. Data sets of 436 titanomagnetite and 206 hornblende analyses from the two sources were used for the study. Titanomagnetite chemistry provided the best discrimination between these two sources with classification efficiencies of 99% for sample averages and 95% for individual analyses. The difference between sources for hornblende chemistry was less marked, but classification efficiencies of 100% for sample averages and 87% for individual analyses were achieved. Using the same methods a preliminary discrimination of individual Egmont volcano-sourced tephras was attempted. Titanomagnetite chemistry enabled the discrimination of several individual tephras or at least pairs of tephra units, but hornblende chemistry provided little discrimination. This technique provides an improvement on previous methods for chemically distinguishing distal tephra from the two sources as well as potentially identifying individual tephras from a particular source. A major advantage over previous discrimination techniques is that individual analyses can be classified with a known probability of group membership (with groups such as volcano source or an individual tephra unit). Tephras in a depositional environment where mixing is common such as within soil, loess and marine sequences, can be sourced or identified more easily with classification of individual grains. Springer-Verlag Berlin Heidelberg, 1996 Key words Tephrostratigraphy nationallicence Egmont volcano nationallicence Tongariro Volcanic Centre nationallicence Discriminant function analysis nationallicence DFA nationallicence Cronin S. J. Department of Soil Science, Massey University, Palmerston North, New Zealand, NZ aut Wallace R. C. Department of Soil Science, Massey University, Palmerston North, New Zealand, NZ aut Neall V. E. Department of Soil Science, Massey University, Palmerston North, New Zealand, NZ aut https://doi.org/10.1007/s004450050123 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s004450050123 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Cronin S. J. Department of Soil Science, Massey University, Palmerston North, New Zealand, NZ aut NATIONALLICENCE 700 1- Wallace R. C. Department of Soil Science, Massey University, Palmerston North, New Zealand, NZ aut NATIONALLICENCE 700 1- Neall V. E. Department of Soil Science, Massey University, Palmerston North, New Zealand, NZ aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer