We use Ar-40-Ar-39 incremental heating to fingerprint bulk fluvial sediment entering the northeast Pacific Ocean, with the long-term intent of tracking sediment source and transport changes from the terrestrial system to the marine environment through time. We show reproducible age spectra from individual rivers accounting for the majority of sediment...
Neogene rocks of the Deschutes basin include the middle Miocene
Columbia River Basalt Group and Simtustus Formation, and late Miocene
to early Pliocene Deschutes Formation. Assignment of Prineville
chemical-type flows to the Grande Ronde Basalt of the Columbia River
Basalt Group is based upon correlation of these lavas from their...
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. Smith for the degree of Doctor of Philosophy in Geology
presented on ,November 19, 1985.
Title
Dust deposition on ecosystems with highly weathered soils may provide vital rock-derived nutrients that maintain ecosystem productivity. Because of the difficulties in measuring temporally and spatially heterogeneous dust deposition over ecologically meaningful timescales, evaluations of the spatial variability in dust deposition are extremely rare. In the Luquillo Mountains of Puerto...
Highlights: New data reveal for the first time a history of the last ∼33.7 ky of uplift of Samosir. Minimum uplift rates were high (4.9 cm/year) for the first 11.2 ky but diminished after that to <1 cm/year for the last 22.5 ky. Numerical modeling suggests that rebound of remnant...
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Department of Geology, University of Illinois -
Urbana-Champaign, Champaign, IL, USA, 4 Geological Agency of
Many ocean regions important to the global carbon budget, including the equatorial Pacific Ocean, have low chlorophyll concentrations despite high levels of conventional nutrients. Iron may instead by the limiting nutrient, and elevated input of terrigenous Fe during windy glacial episodes has been hypothesized to stimulate oceanic productivity through time...
Spatial capture-recapture (SCR) is employed for estimating abundance and density of species, particularly those that are cryptic or solitary, and evaluating how population density varies with habitat. However, it is uncertain whether estimates are biased when applied to species that aggregate, such as elk (Cervus canadensis). Wildlife managers in the...
Development in China over the last thirty years has emphasized infrastructural and economic advancement. Despite enormous gains in living standards in the industrialized eastern provinces, much of China's interior and western provinces remain relatively underdeveloped. Populated mostly by ethnic minorities, the southwest province of Yunnan (meaning south of the clouds)...
Ocean Drilling Program (ODP) Leg 202 has opened a new window
into understanding late Paleogene and Neogene global environmental
change by providing high-quality sediment sequences from a previously
unsampled region, the eastern South Pacific. Eleven sites (1232–
1242) that record variations on timescales ranging from decades to tens
of millions...