Physical Sciences and Mathematics Commons^™

The Birth Of A Forearc: The Basal Great Valley Group, California, Usa, D. A. Orme, Kathleen D. Surpless

Kathleen D. Surpless

The Great Valley basin of California (USA) is an archetypal forearc basin, yet the timing, structural style, and location of basin development remain controversial. Eighteen of 20 detrital zircon samples (3711 new U-Pb ages) from basal strata of the Great Valley forearc basin contain Cretaceous grains, with nine samples yielding statistically robust Cretaceous maximum depositional ages (MDAs), two with MDAs that overlap the Jurassic-Cretaceous boundary, suggesting earliest Cretaceous deposition, and nine with Jurassic MDAs consistent with latest Jurassic deposition. In addition, the pre-Mesozoic age populations of our samples are consistent with central North America sources and do not require a …

Temperaments And Learning Styles Vs. Academic Performance Of First-Semester Physics Students, Shel Randall

Shel Randall

The Diseños Project: A Geospatial Visualization Of The Environmental History Of California, 1769-1892, Rubén Mendoza

Rubén Mendoza

No abstract provided.

Water, Growth And The Endangered Species Act, Holly Doremus

Holly Doremus

24 pages.

Water, Growth And The Endangered Species Act, Holly Doremus

Holly Doremus

24 pages.

Water, Growth And The Endangered Species Act, Holly Doremus

Holly Doremus

24 pages.

Hornbrook Formation, Oregon And California: A Sedimentary Record Of The Late Cretaceous Sierran Magmatic Flare-Up Event, Kathleen D. Surpless

Kathleen D. Surpless

Early Late Cretaceous time was characterized by a major magmatic flare-up event in the Sierra Nevada batholith and early phases of magmatism in the Idaho batholith, but the sedimentary record of this voluminous magmatism in the U.S. Cordillera is considerably less conspicuous. New detrital zircon U-Pb ages from the Hornbrook Formation in southern Oregon and northern California reveal a significant and sustained influx of 100–85 Ma detrital zircons into the broader Hornbrook region beginning ca. 90 Ma. Detrital zircon ages and hafnium isotopic compositions, combined with whole-rock geochemistry, suggest that sediment was largely derived from the Sierra Nevada, requiring uplift …

A Fishery, A Sanctuary, A Sink, And A Disaster: The Often Hapless Management Of California's Salton Sea, William M. Mclaren

Will McLaren

Over a century ago, a series of questionable management decisions and water-diversion engineering mistakes in Southern California produced an “unnatural” waterbody called the Salton Sea. Since then, the Sea has served as a recreational destination with fluctuating popularity, a sanctuary for migratory birds, a sink for agricultural runoff and urban wastewater, and one of the most productive tilapia and corvina fisheries in the United States. However, the Sea’s resources and associated uses have steadily deteriorated since its formation.

The contrast between the ethics that drove resource management decisions at the time of the Salton Sea’s formation to those employed in …

Detrital Zircon Provenance Analysis Of The Great Valley Group, California: Evolution Of An Arc-Forearc System, Kathleen Surpless, Stephan Graham, Joseph Wooden, Michael Mcwilliams

Kathleen D. Surpless

The improved resolution of sediment provenance from detrital zircon analysis of Great Valley stratigraphy enables recognition of previously undocumented arc magmatism and the evolution of regional drainage systems within the Cretaceous arc-forearc system related to uplift, magmatism, and structure in the arc. Great Valley detrital zircon age data confirm previous studies that indicate that the locus of the sediment source in the southern Sierra Nevada arc migrated east with the active volcanic front and suggest rapid rates of uplift and unroofing of the southern arc. Sacramento Valley detrital zircon age data indicate a more complex history of drainage in the …

Managed Care, Hospice Use, Site Of Death, And Medical Expenditures In The Last Year Of Life, Ezekiel Emanuel, Arlene Ash, Wei Yu, Gail Gazelle, Norman Levinsky, Olga Saynina, Mark Mcclellan, Mark Moskowitz

wei yu

BACKGROUND: We examined deaths of Medicare beneficiaries in Massachusetts and California to evaluate the effect of managed care on the use of hospice and site of death and to determine how hospice affects the expenditures for the last year of life.

METHODS: Medicare data for beneficiaries in Massachusetts (n = 37 933) and California (n = 27 685) who died in 1996 were merged with each state's death certificate files to determine site and cause of death. Expenditure data were Health Care Financing Administration payments and were divided into 30-day periods from the date of death back 12 months.

RESULTS: …

In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant

Donald J. Kochan

Significant research has been conducted into the utilization of geothermal resources as a ‘green’ energy source. However, minimal research has been conducted into geothermal resource utilization and depletion impacts on thermophile biodiversity. Thermophiles are organisms which have adapted over millions of year to extreme temperature and chemical compositions and exist in hot springs and other geothermal resources. Their ability to withstand high temperatures makes them invaluable to scientific and medical research. Current federal and California case law classify geothermal resources as a mineral, not a water resource. Acquisition of rights to develop a geothermal resource owned or reserved by the …