Juliet atop a special outcrop of mafic enclaves in Kings Canyon National Park—with more gabbro in view at Volcanic Lakes!!
(A) Geologic map of the study area with a transect and (B) U-Pb zircon ages plotted along the transect.
A cartoon of the Mesozoic subduction zone that formed the Sierra Nevada, showing that mafic intrusions inherit the isotopic fingerprint of their local crustal column.
Juliet atop a special outcrop of mafic enclaves in Kings Canyon National Park—with more gabbro in view at Volcanic Lakes!!
(A) Geologic map of the study area with a transect and (B) U-Pb zircon ages plotted along the transect.
A cartoon of the Mesozoic subduction zone that formed the Sierra Nevada, showing that mafic intrusions inherit the isotopic fingerprint of their local crustal column.
To quantify how much “contamination” occurs in continental arcs, the mafic "starting composition" must be well known. My dissertation research on mafic intrusions across the Sierra Nevada batholith fills this gap in knowledge, and demonstrates that (1) “contamination” of arc magmas occurs early in basaltic compositions and is limited to <~20%, and, (2) upper-plate lithosphere which varies geographically by tectonically assembled belts controls the isotopic heterogeneity and emplacement style of mafic arc magmas over ~100 million years of arc activity.