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Full-Text Articles in Geology
Construction, Emplacement, And Geochemical Evolution Of Deep-Crustal Intrusions: Tenpeak And Dirtyface Plutons, North Cascades, Western North America, Robert B. Miller, Susan M. Debari, Scott R. Paterson
Construction, Emplacement, And Geochemical Evolution Of Deep-Crustal Intrusions: Tenpeak And Dirtyface Plutons, North Cascades, Western North America, Robert B. Miller, Susan M. Debari, Scott R. Paterson
Geology Faculty Publications
Deep plutonic systems represent an important link between lower-crustal melt-generation sites and higher-level regions of magma accumulation, but models for these systems are limited by the relative scarcity of exposed weakly deformed, deep-crustal plutons. Exceptions include the ca. 92.3–89.7 Ma, dominantly tonalitic Tenpeak pluton and the smaller, nearby ca. 91 Ma Dirtyface pluton of the North Cascades (western North America), which represent deeply exposed crustal levels (∼25–35 km) of a Cordilleran arc. Initial subduction-driven magmatism in the Tenpeak pluton was marked by co-magmatic hydrous mafic and felsic magmas, which formed gabbro, diorite, tonalite, and hornblendite within a heterogeneous mafic complex. …
A New Determination Of Pacific-Kula Relative Motions, Harold J. (Harold John) Cashman
A New Determination Of Pacific-Kula Relative Motions, Harold J. (Harold John) Cashman
WWU Graduate School Collection
A new method is presented and used to determine estimates of instantaneous relative motion vectors for the Pacific plate relative to the Farallon and Kula plates between magnetic chrons 34 and 24 (84 to 56 Ma). A weighted chi-square minimization technique was employed that has as input sequential magnetic anomaly picks taken from original ship-track profiles, and fracture-zone azimuths estimated from bathymetric control and offsets in magnetic lineations. Assignment of errors to the input data allows the use of critical chi-square limits to obtain confidence intervals on pole locations and their angular rates. Eleven distinctive magnetic anomalies chosen as control …