USGS Science⌕ Search
Home/Archive/USGS

USGS · 70015881

Age and progression of volcanism, Wrangell volcanic field, Alaska

D.H. Richter·James G. Smith·M. A. Lanphere·G. B. Dalrymple·B.L. Reed·Nora B. Shew
View original source ↗Export metadata ↓

Abstract

The Wrangell volcanic field covers more than 10 000 km2 in southern Alaska and extends uninterrupted into northwest. Yukon Territory. Lavas in the field exhibit medium-K, calc-alkaline affinities, typical of continental volcanic arcs along convergent plate margins. Eleven major eruptive centers are recognized in the Alaskan part of the field. More than 90 K-Ar age determinations in the field show a northwesterly progression of eruptive activity from 26 Ma, near the Alaska-Yukon border, to about 0.2 Ma at the northwest end of the field. A few age determinations in the southeast extension of the field in Yukon Territory, Canada, range from 11 to 25 Ma. The ages indicate that the progression of volcanism in the Alaska part of the field increased from about 0.8 km/Ma, at 25 Ma, to more than 20 km/MA during the past 2 Ma. The progression of volcanic activity and its increased rate of migration with time is attributed to changes in the rate and angle of Pacific plate convergence and the progressive decoupling of the Yakutat terrane from North America. Subduction of Yakutat terrane-Pacific plate and Wrangell volcanic activity ceased about 200 000 years age when Pacific plate motion was taken up by strike-slip faulting and thrusting. ?? 1990 Springer-Verlag.

Explore related subjects

Bulletin of VolcanologyArticle

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

D.H. Richter, James G. Smith, M. A. Lanphere, G. B. Dalrymple, B.L. Reed, Nora B. Shew. 1990. Age and progression of volcanism, Wrangell volcanic field, Alaska. https://doi.org/10.1007/bf00680318

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

KEEP EXPLORING

Related USGS reports

USGS2026

Geophysical insights into Kīlauea’s eruptive reawakening after its 2018 eruption and caldera collapse

A little more than two years after the destructive 2018 lower East Rift Zone eruption and summit collapse ended, renewed volcanic activity began at Kīlauea volcano, Hawaiʻi. During 2020–2025, activity at the volcano included six eruptions in the summit caldera, one in the Southwest Rift Zone, and one in the middle East Rift Zone, as well as multiple non-eruptive intrusions in all three locations. We categorize the volcano’s activity post-2018 into four phases based on eruption locations and style, as well as patterns of magma storage and migration inferred from geophysical data. In some cases, these observations illuminated parts of the volcano’s magmatic system for the first time since the advent of modern geophysical monitoring—particularly deformation datasets that include tilt, continuous GNSS, and InSAR. Analyses of these geodetic data and complementary seismic, geological, and geochemical observations provide an opportunity to explore summit and rift zone connectivity, rift-zone magma storage conditions, the variable geophysical manifestations of eruption onsets, magma-fault interactions, and other long-standing questions associated with eruptions and intrusions at Kīlauea.

Hawaii↗
USGS2026

An extensive and short-lived episode of mid-Holocene fayalite- bearing high-silica rhyolite eruptions at Mono Craters, California

Having last erupted ~ 700 years ago, the Mono Craters volcanic chain is an active system with a history of explosive and effusive high-silica rhyolite eruptions. Approximately ~ 30 lava domes and flows range from ~ 42 to ~ 0.7 ka, form a ~ 15 km curvilinear trend, and change mineralogy (biotite-, orthopyroxene-, or fayalite-bearing) and crystallinity through time. However, the eruptive chronology of this system is incompletely understood. We report new 238 U- 230 Th isochron ages for nine fayalite-bearing domes from paired zircon and allanite crystal surfaces that reveal a major shift in eruptive frequency and volume over the history of the chain, with extrusion of > 0.45 km 3 of high-silica rhyolite lava between 7.1 and 5.2 ka. This contrasts with older biotite- (~ 42–20 ka) and orthopyroxene-bearing (~ 12–9 ka) domes, each of which erupted smaller volumes over a more protracted period. Whole-rock compositions suggest these older domes tapped separate domains within a shared magmatic system because the former are higher in Sr and Ba whereas the latter are lower in SiO 2 , higher in Zr, and more enriched in light rare-earth elements. Titanomagnetite chemistry and zircon saturation temperatures also reflect changing magma compositions and conditions associated with these domes. Fayalite-bearing domes, in contrast, have uniform whole-rock and titanomagnetite compositions which support rapid extrusion of magma over an interval short enough to prevent Fe-Ti oxides from recording any changes in magmatic conditions. The youngest lavas were also produced in a short-lived episode ~ 700 years ago, showing that multivent, geologically brief eruptive episodes occur repeatedly at Mono Craters.

California↗
USGS2026

Satellite observations, plume dynamics and volcanic lightning from the 2023 eruption of Shishaldin Volcano, Alaska

The 2023 eruption of Shishaldin Volcano, Alaska, provided an unusually well-monitored example of a “dry” (non-hydromagmatic) explosive basaltic eruption with sustained, buoyant plumes, and pyroclastic density currents. Here, we examine the 13 basaltic paroxysms that occurred between July and November 2023 using geostationary satellite observations, plume modeling, and volcanic lightning detection to characterize mass eruption rates and plume dynamics. We show that seven volcanic plumes reached 10–14 km above sea level, sustained for minutes to tens of minutes. Translating plume heights into mass eruption rates, using both empirical scaling and one-dimensional plume modeling, gives peak rates of 10 4 –10 7 kg·s −1 and a total erupted volume of ~ 0.05 km 3 (dense rock equivalent) across the eruption sequence. Despite the moderate intensity of this eruption, automated satellite detection algorithms generally failed to detect volcanic ash. We attribute this persistent challenge to the fines-poor grain size distribution of the eruption. Volcanic lightning provides an additional window into the eruption dynamics. A total of 491 volcanic lightning flashes were detected, concentrated during seven of the most energetic phases. The timing of this electrical activity suggests that lightning only became detectable by the global lightning monitoring network when plumes ascended to atmospheric levels favorable for ice formation. Based on the available data, we infer that the low fine ash content of the plumes, combined with minimal water and ice, led to the overall modest rates of lightning (1–13 flashes per minute) compared to “wet” eruptions of similar intensity. These results show that combining satellite observations, plume modeling, and lightning detection provides a valuable timeline of eruptive intensity, even for “dry” basaltic eruptions in remote locations.

Alaska↗