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In a semi-arid, upland setting on the Colorado Plateau that is underlain by nutrient-poor Paleozoic eolian sandstone, alternating episodes of dune activity and soil formation during the late Pleistocene and Holocene have produced dominantly sandy deposits that support grass and shrub communities. These deposits also contain eolian dust, especially in paleosols. Eolian dust in these deposits is indicated by several mineralogic and chemical disparities with local bedrock, but it is most readily shown by the abundance of titaniferous magnetite in the sandy deposits that is absent in local bedrock. Magnetite and some potential plant nutrients (especially, P, K, Na, Mn, and Zn) covary positively with depth (3?4 m) in...
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Thin loess deposits on the uplands of the southeastern Colorado Plateau have previously not been well studied. We sampled deposits and soils from trenches on Hatch Point mesa near Canyonlands National Park, Utah, and from two outcrops in Mesa Verde National Park, Colorado. At Hatch Point, the oldest buried unit yielded two OSL ages of 10,370 and 7,555 yr; the middle unit yielded 10 OSL ages from 6220 to 1385 yr; and the youngest unit has a single age of 1740 yr. At Mesa Verde, three loess units are preserved in the two outcrops we examined; six OSL ages range from 51 to 17 ka. At least one buried soil is present between two units with ages of about 50 and 40 ka. The ages of the loess units in both study areas correspond...
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This dataset consists of tabular information from coastal studies of earthquake and tsunami history along a central part of the Cascadia Subduction Zone. The study area encompasses four estuaries along the Pacific coast of southern Washington and northernmost Oregon. Nearly all the field work took place between 1986 and 1998. Data tables, 18 in all, archive mostly georeferenced information about stratigraphy, radiocarbon ages, and trees dead and living. Some of this data was interpreted in reports published between 1987 and 2005, but most of it was previously unavailable. An accompanying guide, with hyperlinks to the data tables, explains the data tables more thoroughly than does the metadata. Contributors include...
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Eolian dust constitutes most of the pedogenic material in latePleistocene and Holocene soils of many arid regions. Comparison ofthe compositions and influx rates of modern dust with the eoliancomponent of dated soils at 24 sites in southern Nevada andCalifornia yields information on: (1) the composition and influxrate of dust in late Pleistocene and Holocene soils, (2) paleoclimateand its effects on the genesis of aridic soils, especially withregard to "dust events", (3) the timing and relative contribution ofdust from playa sources versus alluvial sources, and (4) the effectsof accumulation of fines in soil horizons. The A and B horizons ofsoils formed on gravelly alluvial-fan deposits in the study area aresimilar...


    map background search result map search result map Late Quaternary eolian dust in surficial deposits of a Colorado Plateau grassland: Controls on distribution and ecologic effects Quaternary Soils and Dust Deposition in Southern Nevada and California Data release for Late Quaternary loess and soils on uplands in the Canyonlands and Mesa Verde areas, Utah and Colorado Data compiled from stratigraphic and tree-ring studies of late Holocene earthquakes and tsunamis at Copalis River, Grays Harbor, Willapa Bay, and Columbia River, Washington and Oregon Late Quaternary eolian dust in surficial deposits of a Colorado Plateau grassland: Controls on distribution and ecologic effects Data compiled from stratigraphic and tree-ring studies of late Holocene earthquakes and tsunamis at Copalis River, Grays Harbor, Willapa Bay, and Columbia River, Washington and Oregon Quaternary Soils and Dust Deposition in Southern Nevada and California