The Late Devonian Corner Bay pluton is a part of the Sitkoh alkaline plutonic complex on the Chichagof Island, southeastern Alaska, which is located in the Alexander terrane of the North American Cordillera. The intrusion, about 12 km long and 4 km wide, is composed predominantly of amphibole-biotite-bearing syenitic/ monzonitic rocks with minor alkaline gabbros and has a U-Pb zircon age of ~367 Ma interpreted as the crystallization age of the pluton. The rocks are metaluminous and have silica contents ranging from 47 to 63 wt% with a silica gap at 52–58 wt% and have high contents of alkalis, typical of shoshonitic rocks. They are rich in large-ion-lithophile elements (including Rb, Sr, Ba, U) and their isotopic composition is characterized by relatively uniform Ɛ_Nd(t) values (+3.4 to +3.7), Neoproterozoic Nd depleted mantle model ages (650–700 Ma) and initial ⁸⁷Sr/⁸⁶Sr ratios (~0.704). The rocks were generated by fractional crystallization of alkali basaltic magma formed by partial melting of an amphibole-phlogopite-bearing peridotite of the sub-arc lithospheric mantle. The mantle-source underwent a Neoproterozoic metasomatic enrichment event and does not show a contribution from juvenile Devonian mantle indicating that rifting associated with the magma emplacement was of limited extent as it did not replace the old lithospheric mantle. Several geothermobarometers document emplacement of the parental magma at mid-crustal levels (8.5–10 kb) and polybaric crystallization from ~1200 °C to solidus. Crystallization of amphibole took place at ~880-980 °C and 2.4–5.5 kb. Subsequently the rocks underwent recrystallization (feldspars: 170 Ma – ⁴⁰Ar/³⁹Ar age) and re-equilibration (biotite: 129 Ma (⁴⁰Ar/³⁹Ar) at ~600-650 °C and 2 kb). Zircon, rutile and apatite saturation temperatures provide consistent results (~800 °C). The intrusion is a part of a metallogenic province of rare metals, which stretched across the islands in the southeastern most part of Alaska.

泥盆纪晚期角Corner岩体是位于阿拉斯加东南部奇查戈夫岛上的契特古碱性岩体的一部分，它位于北美山脉的亚历山大山地。侵入体长约12 km，宽4 km，主要由含角闪石-黑云母的辉长岩/单长岩构成，具有少量碱性辉长岩，U-Pb锆石年龄约为367 Ma，被解释为岩体的结晶年龄。这些岩石是金属质的，二氧化硅含量在47至63 wt％之间，二氧化硅空隙在52–58 wt％之间，并且具有高含量的碱金属，这是生硬岩石中的典型特征。它们富含大离子亲石元素（包括Rb，Sr，Ba，U），其同位素组成的特征是relatively _Nd相对均匀。（t）值（+3.4至+3.7），新元古代Nd耗尽地幔模型年龄（650-700 Ma）和初始⁸⁷ Sr / ⁸⁶Sr比（〜0.704）。这些岩石是由碱性玄武岩岩浆的部分结晶生成的，该岩浆是由亚弧岩石圈地幔中含闪石-金云母的橄榄岩部分熔融而形成的。地幔源区经历了新元古代的交代富集事件，未显示出泥盆纪少年地幔的贡献，这表明与岩浆侵位有关的裂谷作用程度有限，因为它不能代替旧的岩石圈地幔。几个地热气压计记录了中地壳水平（8.5-10 kb）的母岩浆侵位和〜1200°C到固相线的多晶结晶。闪石的结晶发生在约880-980°C和2.4-5.5 kb的温度下。随后，岩石进行了重结晶（长石：170 Ma – ⁴⁰ Ar / ³⁹Ar年龄）并重新平衡（黑云母：约600 Ma / m 2 Ar在约600-650°C时为129 Ma（⁴⁰ Ar / ³⁹ Ar））。锆石，金红石和磷灰石饱和温度可提供一致的结果（约800°C）。入侵是稀有金属成矿省的一部分，稀有金属遍布阿拉斯加最东南部的岛屿。