The Experts below are selected from a list of 2850 Experts worldwide ranked by ideXlab platform
Stephen I. Dworkin - One of the best experts on this subject based on the ideXlab platform.
-
Interpretation of Late Quaternary climate and landscape variability based upon Buried soil macro- and micromorphology, geochemistry, and stable isotopes of soil organic matter, Owl Creek, central Texas, USA
CATENA, 2014Co-Authors: Holly A. Meier, Lee C. Nordt, Steven G Driese, Steven L. Forman, Stephen I. DworkinAbstract:Abstract Small-basin floodplain Buried Soils formed in association with low-order tributary streams are valuable archives of past climates, but have not been studied extensively in central Texas, USA. Four Buried Soils exposed along Owl Creek, within the larger Brazos River drainage basin, were examined using soil morphology and micromorphology, optically stimulated luminescence (OSL) dating, soil characterization, whole-soil geochemical and stable isotope analyses of soil organic matter and pedogenic carbonate. These Buried Soils provide a record of changes in paleoecological and paleo-alluvial conditions spanning ~ 14 ky. Morphological and geochemical differences between Buried Soils reflect changes in landscape attributable to climate, with a distinct 5‰ increase in δ 13 C values of soil organic matter corresponding to the Holocene onset and drier conditions. Paleoecological reconstructions coupled with depth to Bk suggest possible amounts of erosion of ~ 1 m for each of the Buried Soils. Compilation of the proxies presented shows evidence for a cooler and wetter late Pleistocene climate, followed by a warmer and drier climate dominating during the Holocene.
William C. Johnson - One of the best experts on this subject based on the ideXlab platform.
-
Carbon cycle: Sequestration in Buried Soils
Nature Geoscience, 2014Co-Authors: William C. JohnsonAbstract:Rapid deposition of wind-borne silt after the end of the last glacial period Buried a large reservoir of organic carbon in the deep soil. Geochemical analyses suggest that this sequestered soil carbon could be released to the atmosphere if exposed to decomposition.
-
Variation in Radiocarbon Ages of Soil Organic Matter Fractions from Late Quaternary Buried Soils
Quaternary Research, 1995Co-Authors: Charles W. Martin, William C. JohnsonAbstract:Radiocarbon dating of three organic matter fractions (total, humic acid, and residue) isolated from late Quaternary Buried Soils of the central Great Plains reveals that there often are considerable differences among, but no consistent order to, the ages of fractions. For late Holocene Soils, the residue fraction or the total fraction generally produces the oldest age; for late Pleistocene Soils, however, no fraction was consistently the oldest. The absence of a consistent sequence of fraction ages is attributed to postburial contamination of Soils. When bulk samples from the same soil were split and sent to two laboratories, different radiocarbon ages were usually obtained. The variability in radiocarbon ages of soil organic matter confirms that caution should be taken when using radiocarbon ages obtained from different laboratories to make regional stratigraphic correlations.
Steven G Driese - One of the best experts on this subject based on the ideXlab platform.
-
deposition and pedogenesis of periglacial sediments and Buried Soils at the serpentine hot springs archaeological site seward peninsula ak
Catena, 2018Co-Authors: Lyndsay M Dipietro, Steven G Driese, Ted GoebelAbstract:Abstract Soil micromorphology is an excellent tool for relating quantitative laboratory data to soil development in complex pedogenic settings. This study utilizes micromorphology, scanning electron microscopy, bulk soil geochemistry, clay mineralogy, and particle-size analysis to reconstruct the depositional and pedogenic history of the Serpentine Hot Springs fluted point site on the Seward Peninsula, Alaska. Sediment deposition occurred via colluviation, which dominated during the late glacial period and early- to middle-Holocene, and aeolian processes, which dominated during the Younger Dryas (YD) and late Holocene. Two Buried Soils are present: one dating to the Holocene Thermal Maximum (HTM) and the other dating just before the Neoglacial period. Pedofeatures fall into four categories: 1) cryogenic features; 2) clay illuviation features; 3) podzolization/redox features; and 4) anthropogenic features. The spatial relationships among these features provides insight into the pedogenic history of the soil. The HTM soil is characterized by clay illuviation, suggesting warm, mildly acidic, well-drained soil conditions. The pre-Neoglacial soil is characterized by incipient placic horizon development and podzolization, indicative of moist, acidic, variably drained conditions. Cryogenic features associated with late Holocene Neoglaciation dominate the modern soil. Despite cryogenic activity and the presence of permafrost, the cultural stratigraphy of the site remains intact.
-
Interpretation of Late Quaternary climate and landscape variability based upon Buried soil macro- and micromorphology, geochemistry, and stable isotopes of soil organic matter, Owl Creek, central Texas, USA
CATENA, 2014Co-Authors: Holly A. Meier, Lee C. Nordt, Steven G Driese, Steven L. Forman, Stephen I. DworkinAbstract:Abstract Small-basin floodplain Buried Soils formed in association with low-order tributary streams are valuable archives of past climates, but have not been studied extensively in central Texas, USA. Four Buried Soils exposed along Owl Creek, within the larger Brazos River drainage basin, were examined using soil morphology and micromorphology, optically stimulated luminescence (OSL) dating, soil characterization, whole-soil geochemical and stable isotope analyses of soil organic matter and pedogenic carbonate. These Buried Soils provide a record of changes in paleoecological and paleo-alluvial conditions spanning ~ 14 ky. Morphological and geochemical differences between Buried Soils reflect changes in landscape attributable to climate, with a distinct 5‰ increase in δ 13 C values of soil organic matter corresponding to the Holocene onset and drier conditions. Paleoecological reconstructions coupled with depth to Bk suggest possible amounts of erosion of ~ 1 m for each of the Buried Soils. Compilation of the proxies presented shows evidence for a cooler and wetter late Pleistocene climate, followed by a warmer and drier climate dominating during the Holocene.
D.e. Dahms - One of the best experts on this subject based on the ideXlab platform.
-
mid holocene erosion of soil catenas on moraines near the type pinedale till wind river range wyoming
Quaternary Research, 1994Co-Authors: D.e. DahmsAbstract:Abstract Buried Soils are described from the floors of four kettles on Pinedale piedmont moraines of the southwestern Wind River Range, Wyoming, near the type locality of the Pinedale Till. The Buried Soils indicate that a previously unreported episode of slope erosion has occurred along adjacent catenas on some of the moraines in this region. Radiocarbon ages of the Buried Soils indicate that slope erosion occurred during the middle Holocene from 8540 ± 190 to 4800 ± 60 14C yr B.P. The presence of Buried Soils in moraine kettles indicates that profiles on the crests and backslopes of some of the moraines in this region are not the products of continuous post-Pinedale soil formation. Rather, the crest and backslope Soils on Pinedale moraines result from two periods of soil development separated by an interval of erosion. Thus, Soils on crests and backslopes are considered to be welded profiles. Relative-age studies that use soil data to estimate the age of moraines in this region must take into account the possibility that a mid-Holocene erosion episode affected the genesis and morphology of Soils on the moraines. This study corroborates results of previous work that suggests that data from complete catenas are more useful for estimating the characteristic soil development on Quaternary moraines than are data derived from crests alone.
-
Buried Soils of Late Quaternary moraines of the Wind River Mountains, Wyoming
1992Co-Authors: D.e. DahmsAbstract:Buried Soils occur on kettle floors of four Pinedale moraine catenas of the western Wind River Mountains of Wyoming. Radiocarbon ages from bulk samples of Ab horizons indicate the Soils were Buried during the mid-Holocene. Soils on kettle floors have silty A and Bw horizons that overlie Buried A and B horizons that also formed in silt-rich sediments. Crests and backslope Soils also have A and Bw horizons of sandy loam formed over 2BCb and 2Cb horizons of stony coarse loamy sand. Recent data show the silty textures of the A and B horizons are due to eolian silt and clay from the Green River Basin just west of the mountains. The Buried Soils appear to represent alternate periods of erosion and deposition on the moraines during the Holocene. The original Soils developed on higher slopes of the moraines were eroded during the mid-Holocene and the 2BC and 2C horizons exposed at the surface. Eroded soil sediments were transported downslope onto the kettle floors. Following erosion, silt-rich eolian sediments accumulated on all surfaces and mixed with the BC and C horizons (the mixed loess of Shroba and Birkeland). The present surface Soils developed within this silt-rich material. Stone lines oftenmore » occur at the Bw-2BCb/2Cb boundary, and mark the depth to which the earlier Soils were eroded. Thus, soil profiles at the four localities result from two periods of soil formation, interrupted by an interval of erosion during the mid-Holocene. Moraines of this study are adjacent to the Fremont Lake type area for the Pinedale glaciation of the Rocky Mountains. Buried Soils in kettles of the moraines indicates the soil characteristics of the Pinedale type region are not necessarily due to continuous post-Pinedale development, but may result from more than one episode of soil formation.« less
Lee C. Nordt - One of the best experts on this subject based on the ideXlab platform.
-
Interpretation of Late Quaternary climate and landscape variability based upon Buried soil macro- and micromorphology, geochemistry, and stable isotopes of soil organic matter, Owl Creek, central Texas, USA
CATENA, 2014Co-Authors: Holly A. Meier, Lee C. Nordt, Steven G Driese, Steven L. Forman, Stephen I. DworkinAbstract:Abstract Small-basin floodplain Buried Soils formed in association with low-order tributary streams are valuable archives of past climates, but have not been studied extensively in central Texas, USA. Four Buried Soils exposed along Owl Creek, within the larger Brazos River drainage basin, were examined using soil morphology and micromorphology, optically stimulated luminescence (OSL) dating, soil characterization, whole-soil geochemical and stable isotope analyses of soil organic matter and pedogenic carbonate. These Buried Soils provide a record of changes in paleoecological and paleo-alluvial conditions spanning ~ 14 ky. Morphological and geochemical differences between Buried Soils reflect changes in landscape attributable to climate, with a distinct 5‰ increase in δ 13 C values of soil organic matter corresponding to the Holocene onset and drier conditions. Paleoecological reconstructions coupled with depth to Bk suggest possible amounts of erosion of ~ 1 m for each of the Buried Soils. Compilation of the proxies presented shows evidence for a cooler and wetter late Pleistocene climate, followed by a warmer and drier climate dominating during the Holocene.
-
Late quaternary temperature record from Buried Soils of the North American Great Plains
Geology, 2007Co-Authors: Lee C. Nordt, Joseph C. Von Fischer, Larry L. TieszenAbstract:We present the first comprehensive late Quaternary record of North American Great Plains temperature by assessing the behavior of the stable isotopic composition (δ 13 C) of Buried Soils. After examining the relationship between the δ 13 C of topsoil organic matter and July temperature from 61 native prairies within a latitudinal range of 46°–38°N, we applied the resulting regression equation to 64 published δ 13 C values from Buried Soils of the same region to construct a temperature curve for the past 12 k.y. Estimated temperatures from 12 to 10 ka (1 k.y. = 1000 14 C yr B.P.) fluctuated with a periodicity of ∼1 k.y. with two cool excursions between −4.5 and −3.5 °C and two warmer excursions between −1 and 0 °C, relative to modern. Early Holocene temperatures from ca. 10–7.5 ka were −1.0 to −2.0 °C before rising to +1.0 °C in the middle Holocene between 6.0 and 4.5 ka. After a cool interlude from 4.2 to 2.6 ka, when temperatures dropped to slightly below modern, another warm interval ensued from 2.6 to 1 ka as temperatures increased to ∼+0.5 °C. A final decline in temperature to below modern occurred beginning ca. 0.5 ka. Cooler than present temperatures in the Great Plains indicate telecommunications with cool-water episodes in the Gulf of Mexico and North Atlantic potentially governed by a combination of glacial meltwater pulses and low solar irradiance.
