Skip to main content
U.S. flag

An official website of the United States government

Publications

Filter Total Items: 1450

The last interglacial period on the Pacific Coast of North America: Timing and paleoclimate The last interglacial period on the Pacific Coast of North America: Timing and paleoclimate

New, high-precision U-series ages of solitary corals (Balanophyllia elegans) coupled with molluscan faunal data from marine terraces on the Pacific Coast of North America yield information about the timing and warmth of the last interglacial sea-level highstand. Balanophyllia elegans takes up U in isotopic equilibrium with seawater during growth and shortly after death. Corals from the...
Authors
D.R. Muhs, K. R. Simmons, G. L. Kennedy, T. K. Rockwell

The lacustrine carbon cycle as illuminated by the waters and sediments of two hydrologically distinct headwater lakes in north-central Minnesota, U.S.A The lacustrine carbon cycle as illuminated by the waters and sediments of two hydrologically distinct headwater lakes in north-central Minnesota, U.S.A

The accumulation rates of CaCO3 and organic carbon (OC) in lake sediments are delicately balanced between production in the epilimnion and destruction in the hypolimnion. The cycling of these two forms of carbon makes a "carbon pump" that greatly affects the biogeochemical cycles of other elements. To further understand these biogeochemical dynamics, the lakes, streams, and wetlands of...
Authors
Walter E. Dean, Antje Schwalb

Rb-Sr isotopic systematics of lherzolitic shergottite Yamato-793605 Rb-Sr isotopic systematics of lherzolitic shergottite Yamato-793605

No abstract available.
Authors
N. Morikawa, Keiji Misawa, Gabor Kondorosi, Wayne R. Premo, Mistunobu Tatsumoto, Noboru Nakamura

Paleoclimate concepts Paleoclimate concepts

Interpretation of paleoclimate records requires an understanding of Earth’s climate system, the causes (forcings) of climate changes, and the processes that amplify (positive feedback) or damp (negative feedback) these changes. Paleoclimatologists reconstruct the history of climate from proxies, which are those characteristics of sedimentary deposits that preserve paleoclimate...
Authors
Richard B. Ally, Joan J. Fitzpatrick, J. Brigham-Grette, Geoffery L. Miller, Daniel R. Muhs, Leonid Polyak

Biodiversity losses: The downward spiral Biodiversity losses: The downward spiral

The dramatic decline of whitebark pine (Pinus albicaulis) populations in the northwestern United States and southwestern Canada from the combined effects of fire exclusion, mountain pine beetles (Dendroctonus ponderosae), and white pine blister rust (Cronartium ribicola), and the projected decline of whitebark pine populations rangewide (Chapters 10 and 11) do not simply add up to local
Authors
Diana F. Tomback, Katherine C. Kendall

Aeolian dust in Colorado Plateau soils: Nutrient inputs and recent change in source Aeolian dust in Colorado Plateau soils: Nutrient inputs and recent change in source

Aeolian dust (windblown silt and clay) is an important component in arid-land ecosystems because it may contribute to soil formation and furnish essential nutrients. Few geologic surfaces, however, have been characterized with respect to dust-accumulation history and resultant nutrient enrichment. We have developed a combination of methods to identify the presence of aeolian dust in arid...
Authors
Richard L. Reynolds, Jayne Belnap, Paul Lamothe, Fred Luiszer

Age and Pb-Sr-Nd isotopic systematics of plutonic rocks from the Green Mountain magmatic arc, southeastern Wyoming: Isotopic characterization of a Paleoproterozoic island arc system Age and Pb-Sr-Nd isotopic systematics of plutonic rocks from the Green Mountain magmatic arc, southeastern Wyoming: Isotopic characterization of a Paleoproterozoic island arc system

Three new U-Pb zircon ages and the Pb-Sr-Nd isotopic systematics of 24 whole-rock samples from mainly plutonic rocks of the Sierra Madre and Medicine Bow Mountains near the Colorado-Wyoming border help establish the Green Mountain magmatic arc as a Paleoproterozoic, variably eroded, island arc terrane. The Green Mountain magmatic arc, a terrane composed of variably metamorphosed volcanic...
Authors
Wayne R. Premo, R. R. Loucks

Superposed fold-thrust events at the Nevada Test Site Superposed fold-thrust events at the Nevada Test Site

The Nevada Test Site (NTS), in southern Nye County, Nevada, straddles significant pre-Tertiary structural and stratigraphic boundaries. Detailed stratigraphy and biostratigraphy of the Upper Paleozoic section delineates the regional trust sheets and constrains their burial histories. The Paleozoic rocks record three phases of contractional deformation, overprinted by strike-slip faulting...
Authors
Patricia H. Cashman, J. C. Cole, James H. Trexler
Was this page helpful?