Halogens are primarily located within surface reservoirs of the Earth; as such they have proven to be effective tracers for the identification of subducted volatiles within the mantle. Subducting lithologies exhibit a wide variety of halogen compositions, yet the mantle maintains a fairly uniform signature, suggesting halogens may be homogenized...
Lau Basin basalts host an array of geochemical signatures that suggest incorporation of enriched mantle source material often associated with intraplate hotspots, but the origin of these signatures remain uncertain. Geochemical signatures associated with mantle material entrained from the nearby Samoan hotspot are present in northwest Lau Basin lavas, and...
Ocean island basalts (OIB) with extremely radiogenic Pb-isotopic signatures are melts of a mantle component called HIMU (high µ, high ²³⁸U/²⁰⁴Pb). Until now, deeply dredged submarine HIMU glasses have not been available, which has inhibited complete geochemical (in particular, volatile element) characterization of the HIMU mantle. We report major, trace...
The Cobb Seamount Chain in the northeast Pacific basin records the composition of the Cobb hot spot for the past 33 Myr, as the migrating Juan de Fuca Ridge approached and ultimately overran it ca. 0.5 Myr ago. In this first comprehensive geochemical study of the Cobb chain, major and...
Multibeam (1 m resolution) and side scan data collected from an autonomous underwater vehicle, and
lava samples, radiocarbon-dated sediment cores, and observations of flow contacts collected by remotely
operated vehicle were combined to reconstruct the geologic history and flow emplacement processes on
Axial Seamount’s summit and upper rift zones. The...
Multiple episodes of Oligocene and younger silicic volcanism are represented in the high lava plateau of central and southeastern Oregon. From 12 Ma to Recent, volcanism is strongly bimodal with nearly equal volumes of basalt and rhyolite. It is characterized by moderate to high silica (SiO₂ > 72 wt. %)...
A wide variety of different rock types were dredged from the Tonga fore arc and trench between 8000 and 3000 m water depths by the 1996 Boomerang voyage. ⁴⁰Ar-³⁹Ar whole rock and U-Pb zircon dating suggest that these fore arc rocks were erupted episodically from the Cretaceous to the Pliocene...
Strongly bimodal, basalt-rhyolite volcanism of the High Lava Plains Province of Oregon followed the Middle Miocene flood basalts of the Pacific Northwest and extends to recent time. During the 8 m.y. of volcanism recorded in the central High Lava Plains, in western Harney Basin, three distinct mafic magmatic trends originate...
The rare earth elements (REEs) with their systematically varying properties are powerful tracers of continental inputs, particle scavenging intensity and the oxidation state of seawater. However, their generally low (similar to pmol/kg) concentrations in seawater and fractionation potential during chemical treatment makes them difficult to measure. Here we report a...
In this study we present 42 new ⁴⁰Ar/³⁹Ar incremental heating age determinations updated age progression for the Louisville seamount trail. Louisville is the South Hawaiian‐Emperor seamount trail, both trails representing intraplate volcanism (~80 Ma to present) and being examples of primary hot spot lineaments. Our age‐progressive trend from 71 to...