John Tower Jr. ’21 Explores Sodium Metasomatism in the White Mountain Peak Metavolcanic Complex
The White Mountain Peak Metavolcanic Complex, east-central California and Nevada is part of the Mesozoic Cordilleran continental arc. These rocks have undergone extensive metamorphism and metasomatism both early in the history of the magmatic arc and when later plutons intruded the volcanic pile. My project will utilize whole rock major and trace element data to constrain the history of this alteration and help identify the original protoliths.
The central concern of this thesis is how and where sodium metasomatism occurred. This study will combine whole rock geochemistry with petrography to identify the geographic distribution of sodium metasomatism in the White Mountains. The region has a complicated alteration history. Low temperature potassium metasomatism happened soon after the formation of the volcanic complex. Subsequently the rocks were intruded by the Barcroft pluton and metamorphosed to the albite epidote facies. The rocks were then intruded by the Pelsier Flats pluton in the Cretaceous which accompanied sodium metasomatism. The objective of this thesis is to detect the levels of sodium within the volcanic complex. How widespread was metasomatism in the White Mountain Peak Volcanic Complex? A prior investigation from the geology department shows the volcanic rocks are rich in albite (Na-rich feldspar). This study will help determine whether this is the result of the metamorphism of the subsequent sodium metasomatism.