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Structural And Geochronologic History Of Southern Alaskan Blueschists, Erik M. Day

Open Access Theses & Dissertations

Detrital zircon data are presented from the Liberty Creek blueschist in the central Chugach Mountains which indicate two distinct periods of the preservation of blueschist facies metamorphism along the southern Alaskan margin. A maximum depositional age of ~136 Ma demonstrates that the Liberty Creek schist was deposited long after the Jurassic cooling ages (196-185 Ma; Lopez-Carmona et al., 2011) recorded in western Alaskan blueschist bodies, revealing two blueschist preservation events. This Early Cretaceous depositional age also indicates that there have been major reorganizations within this subduction complex because the Potter Creek assemblage, directly south of the Liberty Creek schist, is …