Climatic Oscillations 10,000–155,000 yr B.P. at Owens Lake, California Reflected in Glacial Rock Flour Abundance and Lake Salinity in Core OL-92

1997 ◽  
Vol 48 (3) ◽  
pp. 313-325 ◽  
Author(s):  
James L. Bischoff ◽  
Kirsten M. Menking ◽  
Jeffrey P. Fitts ◽  
John A. Fitzpatrick
Keyword(s):  
Sierra Nevada ◽  
Clay Fraction ◽  
Size Fraction ◽  
Glacial Cycle ◽  
Abrupt Decrease ◽  
Climatic Oscillations ◽  
Owens Lake ◽  
Clay Size Fraction ◽  
High Carbonate ◽  
Lake Salinity

Chemical analyses of the acid-soluble and clay-size fractions of sediment samples (1500-yr resolution) reveal oscillations of lake salinity and of glacial advances in core OL-92 back to 155,000 yr B.P. Relatively saline conditions are indicated by the abundance of carbonate and smectite (both pedogenic and authigenic), reflected by Ca, Sr, and Mg in the acid-soluble suite, and by Cs2O, excess MgO, and LOI (loss on ignition) in the clay-size fraction. Rock flour produced during glacial advances is represented by the abundance of detrital plagioclase and biotite in the clay-size fraction, the ratio of which remains essentially constant over the entire time span. These phases are quantitatively represented by Na2O, TiO2, Ba, and Mn in the clay fraction. The rock-flour record indicates two major ice-advances during the penultimate glacial cycle corresponding to marine isotope stage (MIS) 6, no major advances during the last interglaciation (entire MIS 5), and three major advances during the last glacial cycle (MIS 2, 3, and 4). The ages of the latter three correspond rather well to36Cl dates reported for Sierra Nevada moraines. The onset of the last interglaciation is shown by abrupt increases in authigenic CaCO3and an abrupt decrease in rock flour, at about 118,000 yr B.P. according to our time scale. In contrast, the boundary appears to be gradual in the δ18O record in which the change from light to heavy values begins at about 140,000 yrs B.P. The exact position of the termination, therefore, may be proxy-dependent. Conditions of high carbonate and low rock flour prevailed during the entire period from 118,000 yr B.P. until the glacial advance at 53,000 yr B.P. signaled the end of this long interglaciation.

scholarly journals Continuous Lake-Sediment Records of Glaciation in the Sierra Nevada between 52,600 and 12,50014C yr B.P

1998 ◽  
Vol 50 (2) ◽  
pp. 113-127 ◽  
Author(s):  
Larry V. Benson ◽  
Howard M. May ◽  
Ronald C. Antweiler ◽  
Terry I. Brinton ◽  
Michaele Kashgarian ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Organic Carbon ◽  
Total Organic Carbon ◽  
Lake Sediments ◽  
Sierra Nevada ◽  
Lake Sediment ◽  
Size Fraction ◽  
Alpine Glacier ◽  
Owens Lake ◽  
Clay Size Fraction

The chemistry of the carbonate-free clay-size fraction of Owens Lake sediments supports the use of total organic carbon and magnetic susceptibility as indicators of stadial–interstadial oscillations. Owens Lake records of total organic carbon, magnetic susceptibility, and chemical composition of the carbonate-free, clay-size fraction indicate that Tioga glaciation began ∼24,500 and ended by ∼13,60014C yr B.P. Many of the components of glacial rock flour (e.g., TiO2, MnO, BaO) found in Owens Lake sediments achieved maximum values during the Tioga glaciation when valley glaciers reached their greatest extent. Total organic carbon and SiO2(amorphous) concentrations reached minimum values during Tioga glaciation, resulting from decreases in productivity that accompanied the introduction of rock flour into the surface waters of Owens Lake. At least 20 stadial–interstadial oscillations occurred in the Sierra Nevada between 52,600 and 14,00014C yr B.P. Total organic carbon data from a Pyramid Lake sediment core also indicate oscillations in glacier activity between >39,500 and ∼13,60014C yr B.P. Alpine glacier oscillations occurred on a frequency of ≤1900 yr in both basins, suggesting that millennial-scale oscillations occurred in California and Nevada during most of the past 52,600 yr.

Clay resources in the Nelas region (Beira Alta), Portugal. A contribution to the characterization of potential raw materials for prehistoric ceramic production

Clay Minerals ◽  
2010 ◽  
Vol 45 (3) ◽  
pp. 353-370 ◽  
Author(s):  
R. Marques ◽  
A. Jorge ◽  
D. Franco ◽  
M. I. Dias ◽  
M. I. Prudêncio
Keyword(s):  
Chemical Elements ◽  
Raw Materials ◽  
Bulk Material ◽  
Clay Fraction ◽  
Size Fraction ◽  
Chemical Compositions ◽  
River Bank ◽  
Clay Size Fraction ◽  
Ancient Ceramic

AbstractMineralogical and chemical compositions of residual and sedimentary clays (bulk and <2 μm fraction) from the Nelas region (schist, aplite-pegmatites, granites and Tertiary sediments from both Mondego River margins), Portugal, were studied, aiming to establish indicators for raw materials in ancient ceramic provenance studies. The mineralogy of bulk material does not provide a clear distinction between samples. Among clay minerals, kaolinite dominates, except in the aplite-pegmatites where illite prevails. Smectite was only found in sediments of the left river bank.A more successful result was the geochemical differentiation of clay types. The weathered schist presents greater enrichment in Cr, whereas the clay fraction of aplite-pegmatites shows enrichment in all the chemical elements studied. The sediments and weathered granites are not easy to differentiate; the best geochemical indicators are U (lower contents in clay-size fraction of sediments) and REE patterns in both bulk and clay-size fraction.

scholarly journals Long term trends in fertility of soils under continuous cultivation and cereal cropping in southern Queensland. III. Distribution and kinetics of soil organic carbon in particle size fractions

Soil Research ◽  
1986 ◽  
Vol 24 (2) ◽  
pp. 293 ◽  
Author(s):  
RC Dalal ◽  
RJ Mayer
Keyword(s):  
Particle Size ◽  
Organic Matter ◽  
Organic Carbon ◽  
Soil Organic Carbon ◽  
Size Fraction ◽  
Organic C ◽  
Size Fractions ◽  
Particle Size Fractions ◽  
Clay Size Fraction ◽  
Sand Size

Distribution of soil organic carbon in sand-, silt- and clay-size fractions during cultivation for periods ranging from 20 to 70 years was studied in six major soils used for cereal cropping in southern Queensland. Particle-size fractions were obtained by dispersion in water using cation exchange resin, sieving and sedimentation. In the soils' virgin state no single particle-size fraction was found to be consistently enriched as compared to the whole soil in organic C in all six soils, although the largest proportion (48%) of organic C was in the clay-size fraction; silt and sand-size fractions contained remaining organic C in equal amounts. Upon cultivation, the amounts of organic C declined from all particle-size fractions in most soils, although the loss rates differed considerably among different fractions and from the whole soil. The proportion of the sand-size fraction declined rapidly (from 26% to 12% overall), whereas that of the clay-size fraction increased from 48% to 61% overall. The proportion of silt-size organic C was least affected by cultivation in most soils. It was inferred, therefore, that the sand-size organic matter is rapidly lost from soil, through mineralization as well as disintegration into silt-size and clay-size fractions, and that the clay fraction provides protection for the soil organic matter against microbial and enzymic degradation.

Determination of Clay Size Fraction of Marine Clays

1991 ◽  
Vol 14 (1) ◽  
pp. 103 ◽  
Author(s):  
PC Knodel ◽  
A Sridharan ◽  
BT Jose ◽  
BM Abraham
Keyword(s):  
Size Fraction ◽  
Clay Size Fraction ◽  
Marine Clays

Nature and origin of lipids in clay size fraction of a cultivated soil as revealed using preparative thermochemolysis

2009 ◽  
Vol 40 (1) ◽  
pp. 70-78 ◽  
Author(s):  
L. Grasset ◽  
J. Martinod ◽  
A.F. Plante ◽  
A. Amblès ◽  
C. Chenu ◽  
...  
Keyword(s):  
Size Fraction ◽  
Clay Size Fraction ◽  
Cultivated Soil

A 180,000-year pollen record from Owens Lake, CA: terrestrial vegetation change on orbital scales

2003 ◽  
Vol 59 (3) ◽  
pp. 430-444 ◽  
Author(s):  
Wallace B. Woolfenden
Keyword(s):  
Sierra Nevada ◽  
Vegetation Change ◽  
Vegetation History ◽  
Pollen Record ◽  
Terrestrial Vegetation ◽  
Subalpine Forests ◽  
Owens Lake ◽  
Ice Cap ◽  
Juniper Woodland ◽  
Warm Desert

AbstractPollen from the upper 90 m of core OL-92 from Owens Lake is a climatically sensitive record of vegetation change that indicates shifts in the plant associations representing warm and cold desertscrub, pinyon–juniper woodland, and pine–fir forest during the past 180,000 years. These changes are synchronized with glacial–interglacial cycles. During glacial and stadial climates, juniper woodland expanded downslope and replaced warm desert shrubs while upper montane and subalpine forests in the arid Inyo Mountains also expanded, and those in the Sierra Nevada were displaced by the ice cap and periglacial conditions. Conversely, during interglacial and interstadial climates, warm desert plants expanded their range in the lowlands, juniper and sagebrush retreated upslope, and montane and subalpine forests expanded in the Sierra Nevada. The reconstructed vegetation history demonstrates a regional climatic response, and the congruence of the pollen sequence with marine and ice cap oxygen isotope stratigraphies suggests a link between regional vegetation and global climate change at orbital scales.

scholarly journals Impact of In Situ Soil in Soil-Bentonite Cutoff Wall Backfill on Compressibility and Hydraulic Conductivity

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Ridong Fan ◽  
Yuling Yang ◽  
Songyu Liu
Keyword(s):  
Hydraulic Conductivity ◽  
Void Ratio ◽  
Size Fraction ◽  
Characteristic Parameter ◽  
Compression Index ◽  
Natural Clay ◽  
Cutoff Wall ◽  
Clay Size Fraction ◽  
The Impact

Soil-bentonite cutoff walls, consisting of excavated in situ soil and bentonite as backfills, are used extensively as vertical barriers for groundwater pollution control. Sand mixed with high-quality natural sodium bentonite (NaB) is commonly used as a research object to investigate the hydraulic and compression properties of soil-bentonite backfills. However, pure sand could rarely be found in real conditions, and natural NaB may not be available readily in some countries such as China, India, and Turkey. This paper presents a comprehensive laboratory investigation on the compressibility and hydraulic conductivity (k) of soil-bentonite backfills created by simulated in situ soil and low-quality sodium activated calcium bentonite (SACaB). The simulated in situ soils are prepared using sand-natural clay mixtures with sand to natural clay mass ratios ranging from 0.5 to 6.0, and the bentonite content (BC) in the base mixture ranges from 0 to 15%. The result indicates that BC dominates the compression index (Cc) of the backfill, and a unique relationship between void ratio at effective vertical compression stress of 1 kPa and compression index is proposed for various types of soil-bentonite backfills. An increase in either BC or clay size fraction (CF) in simulated in situ contributes to reducing k, but the impact of CF in simulated in situ soil on k tends to be insignificant for backfill with BC higher than 6%. A new characteristic parameter based on the concept of void ratio of bentonite (eb), named apparent void ratio of clay size fraction (eC), is developed for predicting soil-bentonite backfills created by in situ soils and bentonites with various contents.

Late-Glacial and Early Holocene Vegetation and Climate Change near Owens Lake, Eastern California

2001 ◽  
Vol 55 (1) ◽  
pp. 57-65 ◽  
Author(s):  
Scott A. Mensing
Keyword(s):  
Climate Change ◽  
Sierra Nevada ◽  
Great Basin ◽  
Younger Dryas ◽  
Late Glacial ◽  
Lake Levels ◽  
Owens Valley ◽  
Desert Shrubs ◽  
Owens Lake ◽  
Lake Record

AbstractPollen and algae from Owens Lake in eastern California provide evidence for a series of climatic oscillations late in the last glaciation. Juniper woodland, which dominated the Owens Valley from 16,200 to 15,500 cal yr B.P., suggests much wetter conditions than today. Although still wetter and cooler than today, the area then became fairly warm and dry, with woodland being replaced by shrubs (mainly sagebrush) from 15,500 to 13,100 cal yr B.P. Next, Chenopodiaceae (shadscale) increased, woody species declined, and lake levels fell—all evidence for a brief (ca. 100–200 yr) drought about 13,000 cal yr B.P. The climate continued to oscillate between wet and dry from 13,000 to 11,000 cal yr B.P. After 11,000 cal yr B.P., low lake levels and the increased dominance of desert shrubs indicate the beginning of warm, dry Holocene conditions. The region's climate was unstable during the Younger Dryas but uncertainities in dating prevent identification of the Younger Dryas interval in the Owens Lake record. Comparison of the Owens Lake record with studies in the Sierra Nevada and Great Basin suggest that the climate was generally wetter between 13,000 and 11,000 cal yr B.P., with warmer summers, although no consistent pattern of climate change emerges.

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