Revisiting the geochronology of late Quaternary marine terraces and uplift rates in coastal Santa Barbara County, California, USA

Geomorphology
By: , and 

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Abstract

In several early studies, central California marine terraces between Santa Barbara and Point Conception were interpreted to record sea-level high stands of the last interglacial complex, ∼80 ka to ∼120 ka (marine isotope stage [MIS] 5). These ages and their elevations (∼20 m to ∼45 m) indicate modest rates of tectonic uplift, similar to those from other localities in southern and central California. A recent study, using a combination of luminescence and radiocarbon dating, has challenged the older age interpretations, implying much younger terrace ages, between ∼40 ka and ∼55 ka (MIS 3). From these new ages and a considerably lower sea level during MIS 3, much higher rates of tectonic uplift are inferred. In the present study, new uranium-series ages of terrace corals and amino acid age estimates of terrace mollusks were determined to test these competing interpretations. With the exception of a low-elevation terrace in Isla Vista (near Santa Barbara) that dates to MIS 3, terraces farther west are interpreted to date to MIS 5 and imply tectonic uplift rates of 0.20–0.34 m/kyr. A compilation of data for the region yields a decreasing rate of late Quaternary uplift from east, near Ventura, to west, near Point Conception. This trend is interpreted to reflect a decreasing influence of the processes of compression and crustal shortening south of the Big Bend in the San Andreas fault.

Suggested Citation

Muhs, D., Schumann, R.R., Bright, J., Roberts, H.M., and Groves, L.T., 2026, Revisiting the geochronology of late Quaternary marine terraces and uplift rates in coastal Santa Barbara County, California, USA: Geomorphology, v. 501, 110179, 29 p., https://doi.org/10.1016/j.geomorph.2026.110179.

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Publication type Article
Publication Subtype Journal Article
Title Revisiting the geochronology of late Quaternary marine terraces and uplift rates in coastal Santa Barbara County, California, USA
Series title Geomorphology
DOI 10.1016/j.geomorph.2026.110179
Volume 501
Year Published 2026
Language English
Publisher Elsevier
Contributing office(s) Geosciences and Environmental Change Science Center
Description 110179, 29 p.
Country United States
State California
County Santa Barbara County
Other Geospatial coastal Santa Barbara County
Additional publication details