Document Type
Contribution to Book
Publication Date
11-17-2025
Abstract
Details of the Late Jurassic tectonic evolution of the North American continental margin remain controversial, but a clear understanding of Late Jurassic tectonics is essential for understanding subsequent terrane accretion and displacement. Upper Jurassic strata of the Galice Formation in the western Klamath Mountains province and the Mariposa Formation in the Western Sierra Nevada metamorphic province were deposited along the margin of North America during this critical time. The Galice and Mariposa Formations have long been correlated, and these strata are the youngest rocks deformed during Late Jurassic Nevadan deformation in Oregon and California. Published and new detrital zircon age and εHf data sets from the Galice Formation (N = 30; n-age = 7287; n-Hf = 876) and Mariposa Formation (N = 13; n-age = 3656; n-Hf = 484) confirm previous correlations between Galice and Mariposa strata and require that abundant continentally derived zircon reached both basins with the onset of turbidite deposition ca. 159 Ma. However, subtle differences between the pre-Mesozoic age distributions and Mesozoic zircon εHf values compiled for each basin reveal nuances in provenance that can be directly related to the location of each basin relative to sediment sources within the magmatic arc and retroarc region. Mixture modeling indicates that the relative latitudinal position of the Galice and Mariposa basins with respect to their source regions can account for the differences in source contributions to each basin, and our results indicate < 200 km of post-Jurassic dextral displacement within the Sierra Nevada magmatic arc. These geochemical and age-based provenance results, combined with depositional age constraints for each basin, are most consistent with models for the Late Jurassic Nevadan orogeny that call on changing plate kinematics during eastward subduction that resulted in periods of transtension and transpression along the margin, rather than westward subduction of the North American plate beneath an island archipelago or double subduction of the Mezcalero plate.
Editor
Stacia M. Gordon, Robert B. Miller, Margaret E. Rusmore, Basil Tikoff
DOI
https://doi.org/10.1130/2025.2565(10)
Publisher
GeoScienceWorld
ISBN
9780813795652
Repository Citation
Surpless, K. D., Barnes, C., & Yoshinobu, A. (2025). Record of the late jurassic cordilleran margin from detrital zircon analysis of the Galice and Mariposa Formations, California and Oregon. Jurassic–Paleogene Tectonic Evolution of the North American Cordillera. https://doi.org/10.1130/2025.2565(10)