Coastal tectonics on the eastern margin of the Pacific Rim: Late Quaternary sea-level history and uplift rates, Channel Islands National Park, California, USA

Daniel R. Muhs; Kathleen R. Simmons; R. Randall Schumann; Lindsey T. Groves; Stephen B. DeVogel; Scott A. Minor; Deanna Laurel

doi:10.1016/j.quascirev.2014.09.017

USGS · 70159904

Coastal tectonics on the eastern margin of the Pacific Rim: Late Quaternary sea-level history and uplift rates, Channel Islands National Park, California, USA

Daniel R. Muhs·Kathleen R. Simmons·R. Randall Schumann·Lindsey T. Groves·Stephen B. DeVogel·Scott A. Minor·Deanna Laurel

View original source ↗Export metadata ↓

Abstract

The Pacific Rim is a region where tectonic processes play a significant role in coastal landscape evolution. Coastal California, on the eastern margin of the Pacific Rm, is very active tectonically and geomorphic expressions of this include uplifted marine terraces. There have been, however, conflicting estimates of the rate of late Quaternary uplift of marine terraces in coastal California, particularly for the orthern Channel Islands. In the present study, the terraces on San Miguel Island and Santa Rosa Island were mapped and new age estimates were generated using uranium-series dating of fossil corals and amino acid geochronology of fossil mollusks. Results indicate that the 2nd terrace on both islands is ~120 ka and the 1st terrace on Santa Rosa Island is ~80 ka. These ages correspond to two global high-sea stands of the Last Interglacial complex, marine isotope stages (MIS) 5.5 and 51, respectively. The age estimates indicate that San Miguel Island and Santa Rosa Island have been tectonically uplifted at rates of 0.12e0.20 m/ka in the late Quaternary, similar to uplift rates inferred from previous studies on neighboring San Cruz Island. The newly estimated uplift rates for the northern Channel Islands are, however, an order of magnitude lower than a recent study that generated uplift rates from an offshore terrace dating to the Last Glacial period. The differences between the estimated uplift rates in the present study and the offshore study are explained by the magnitude of glacial isostatic adjustment (GIA) effects that were not known at the time of the earlier study. Set in the larger context of northeastern Pacific Rim tectonics, Channel Islands uplift rates are higher than those coastal localities on the margin of the East Pacific Rise spreading center, but slightly lower than those of most localities adjacent to the Cascadia subduction zone. The uplift rates reported here for the northern Channel Islands are similar to those reported for most other localities where strike-slip tectonics are dominant, but lower than localities where restraining bends (such as the Big Bend of the San Andreas Fault) result in crustal shortening.

Explore related subjects

Quaternary Science Reviews Article

Source-reported bounding extent: 33.445193134508465° to 34.120900139826965° latitude; -120.52001953124999° to -118.99291992187499° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Daniel R. Muhs, Kathleen R. Simmons, R. Randall Schumann, Lindsey T. Groves, Stephen B. DeVogel, Scott A. Minor, Deanna Laurel. 2014. Coastal tectonics on the eastern margin of the Pacific Rim: Late Quaternary sea-level history and uplift rates, Channel Islands National Park, California, USA. https://doi.org/10.1016/j.quascirev.2014.09.017

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

A 30,000-year continuous record of glacial history and water balance from Fish Lake, Utah documents the onset, development, and demise of LGM glaciation

Fish Lake provides a continuous, high-resolution freshwater paleoclimate archive of glacial and hydroclimate history from a catchment straddling the Colorado Plateau–Great Basin boundary in the western US. At >3600 m, the Fish Lake Plateau glaciates during stadials, making it an ideal site for tracking the region's glacial history. The high-resolution (>3.3 mm/decade) record contains multiple climate- and ecosystem-sensitive proxies. Geochronology relies on 210 Pb and AMS 14 C measurements on terrestrial macrofossils and charcoal, tephrochronology, and paleomagnetic measurements. Multiproxy analyses include indicators of glacial erosion (magnetic susceptibility, sediment density, % mineral matter, grainsize, scanning XRF) and biological productivity (biogenic silica, organic matter). These proxies show glacial inception during the local Last Glacial Maximum at 25.8 ka, coincident with Heinrich Stadial 2, with maximum down-valley ice expansion between 24.8 and 20.9 ka. Glaciers reached the shoreline but did not override the lake, and sedimentation rates did not exceed Holocene levels, as increased glacial erosion was offset by reduced productivity in the glaciated, turbid lake. Deglaciation began by 18.2 ka, was interrupted by a readvance under wetter conditions synchronous with Heinrich Stadial 1 and concluded with final catchment deglaciation ∼14.1 ka. After 13.7 ka, productivity proxies rise rapidly and remain high through the Holocene while erosion proxies drop abruptly. Comparison with the adjacent Bonneville pluvial lake-level record shows that glacial onset on the Fish Lake Plateau preceded the rise in Bonneville water levels at ∼24 ka by roughly a millennium, implying temperature decreases led P-E increases. Similarly, deglaciation onset preceded falling Bonneville water levels by several centuries.

Utah↗

USGS2026

Sedimentological reconstruction of hurricane storm surges from a carbonate reef coastline at Anegada, British Virgin Islands

Anegada is a small, low-lying carbonate island in the British Virgin Islands that is highly vulnerable to marine inundation from frequent hurricanes. A major challenge in forecasting the timing, intensity, and impacts of future hurricanes to islands such as Anegada is the limited short-term instrumental record that does not capture the full spectrum of inundation events from the frequent but low-magnitude to rare, but high-magnitude events. Washover deposits, which are transported onshore by hurricane-related storm surges and preserved within the onshore stratigraphy, can provide insight into the recurrence of these events. Here, we use grain size distributions, X-ray fluorescence (XRF) data, and an inverse sediment transport model to characterize a series of anomalous sand deposits from shallow hypersaline ponds to determine the variability in storm surges impacting Anegada over at least the last 70 years. The analyses were successfully applied to modern analogues of storms impacting Anegada's southern shoreline (Hurricanes Donna in 1960 at Category 3; Earl in 2010 at Category 4; and Irma in 2017 at Category 5). These deposits are identified by coarse-grained material and elevated marine geochemical signals (Ca, Sr, ln(Br/Ti)). Inverse modelled flow parameters (average flow depth = 0.89–1.46 m relative to the reef flat, average flow speed = 2.95–3.78 m/s) agree with observational data and eyewitness accounts, and the deposit associated with Hurricane Donna indicates the greatest impacts occurred along the southern shoreline (modelled flow depth = 1.24–1.46 m relative to the reef flat, flow speed = 3.49–3.78 m/s). Using the modern analogues as a basis for comparison, we infer the origin of an older sand deposit to be from Hurricane Dog in 1950, when it tracked by Anegada as a Category 3 storm. This methodology provides a transferable framework for interpreting storm recurrence in carbonate-dominated coastlines worldwide that could be used to inform hurricane hazard assessments and risk management efforts.

Anegada↗

USGS2026

Temperature and precipitation source variability and glacial dynamics in the southwestern United States at Fish Lake, Utah, since late MIS 4

An improved understanding of hydroclimate response to natural climate forcings is needed to evaluate impacts of changing seasonal circulation patterns on current and future drought in the southwestern United States (‘the Southwest’). However, few terrestrial records from the Southwest preserve changes in moisture availability continuously prior to the Last Glacial Maximum (LGM, ∼24.5 ka). Fish Lake, in the Upper Colorado River Basin, preserves a long (∼67 ka), continuous, high-resolution (∼3.3 cm/century) sedimentary record spanning from late Marine Isotope Stage (MIS) 4 to present. Here, we investigate the relative contributions of seasonal precipitation and moisture source using the hydrogen isotope value of the n -C 29 leaf wax alkane and changes in temperature using branched glycerol dialkyl glycerol tetraethers (brGDGTs). During the warm post glacial period (14 ka to present), a greater contribution of annual precipitation is sourced from the North American Monsoon (NAM) in response to declining winter insolation and rising greenhouse gases, weakening westerly storms and shifting them northward. MIS 3 (∼61 to 29 ka) is also influenced by NAM inputs, however, to a smaller magnitude than during the post glacial period when temperatures were warmer. However, stadial periods (MIS 2, 29 to 14.1 ka) show 2 H-enriched values, suggesting warm conditions and large contributions of NAM precipitation during the LGM, contradicting other proxies and regional records. The LGM is the only period in the record where glaciers are present in the catchment, thus we hypothesize glacial erosion reworked pre-LGM aged soil organic matter and biased the record during this time.

Utah↗