Reconnaissance geochemistry of Permian and Triassic basalts of the Taku and Wrangellia terranes, southeastern Alaska

Major and minor element geochemical data are presented for Permian and Triassic basalts that belong to the Taku terrane, and for Triassic basalts of the Wrangellia terrane. The Permian rocks are high-magnesian alkaline basalts, whereas the Upper Triassic rocks are similar to midocean ridge or within-plate tholeiites. The data indicate that the Triassic rocks of the Taku and Wrangellia terranes are very similar chemically, which supports previous stratigraphic correlations between these two sequences. The Wrangellia and Taku terranes either evolved in close proximity to each other during Late Triassic time, or the Taku terrane of the Juneau-Port Houghton area actually is a facies of the Wrangellia terrane. -from Authors