Measurements of helium isotopes in particles separated from polar ice demonstrate that extraterrestrial ³He dominates the ³He flux at the GISP2 (Greenland) and Vostok (Antarctica) ice core sites. Replicate measurements of late Holocene ice samples yield ³He fluxes of 0.62±0.27×10⁻¹² cm³ STP cm⁻² ka⁻¹ (GISP2) and 0.77 ± 0.25 ×...
In order to determine whether the sediments found on the landward
wall of the Peru Trench are accreted Nazca Plate sediments,
the clay mineralogy and organic carbon contents of 52 surface
samples were submitted to factor analysis. Q-mode factor analysis
resolved the data from the Nazca Plate and Peru continental...
We analyze merger parameters of binary black hole systems (BBHSs), including orbital separation and time at which gravitational and viscous timescales intersect for all combinations of black holes (BHs) in the range 1-100 solar masses. Our initial examination of BBHS merger parameters using the assumption R=0.5r reveals suspicious trends in...
Oregon estuaries provide important opportunities to assess controls on tidal saline wetland carbon burial and sediment accretion as both rates of relative sea level rise (RSLR; −1.4 ± 0.9 to 2.8 ± 0.8 mm yr⁻¹) and fluvial suspended sediment load relative to estuary area (0.23 to 17 × 10³ t...
Quantification of contemporary sediment and carbon accumulation within Oregon tidal saline wetlands will: (1) fill a critical knowledge gap, and (2) naturally test without complicating variables whether sea level rise or sediment supply primarily control wetland growth. Here we measure vertical accretion rates and carbon burial rates in three Oregon...
Short gamma-ray bursts (GRBs) are explosions of cosmic origins believed to be associated with the merger of two compact objects, either two neutron stars or a neutron star and a black hole (BH). The presence of at least one neutron star has long been thought to be an essential element...
Patterns of beach erosion and accretion due to jetty construction
are examined for the coast of Oregon. All jetty systems are
included with the exception of those on the Columbia River, making a
total of nine systems.
All evidence indicates that these areas of the Oregon coast are
experiencing a...
Tidal marshes are dynamic ecosystems that are threatened by climate change and sea-level rise. To characterize baseline condition and historic climate sensitivities, and improve projections into the future, new methods are required that integrate data from the field and remote sensing platforms. Marsh elevation response models can be calibrated with...
The Franciscan Complex accretionary prism was assembled during an similar to 165-m.y.-long period of subduction of Pacific Ocean plates beneath the western margin of the North American plate. In such fossil subduction complexes, it is generally difficult to reconstruct details of the accretion of continent-derived sediments and to evaluate the...
Siletzia is a basaltic Paleocene and Eocene
large igneous province in coastal Oregon,
Washington, and southern Vancouver Island
that was accreted to North America in the
early Eocene. New U-Pb magmatic, detrital
zircon, and ⁴⁰Ar/³⁹Ar ages constrained by
detailed field mapping, global nannoplankton
zones, and magnetic polarities allow correlation
of...
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Chron
25–22 plate reorganization in the north-
east Pacifi c basin. Accretion was completed
between 51