Metadata: Identification_Information: Citation: Citation_Information: Originator: Reheis, Marith C. Originator: Goodmacher, Johnathan C. Originator: Harden, Jennifer W. Originator: McFadden, Leslie D. Originator: Rockwell, Thomas K. Originator: Shroba, Ralph R. Originator: Sowers, Janet M. Originator: Taylor, Emily M. Publication_Date: 1995 Title: Quaternary Soils and Dust Deposition in Southern Nevada and California Geospatial_Data_Presentation_Form: model Series_Information: Series_Name: Geological Society of America Bulletin Issue_Identification: volume 107 Publication_Information: Publication_Place: Kansas Publisher: Geological Society of America Online_Linkage: Description: Abstract: Eolian dust constitutes most of the pedogenic material in late Pleistocene and Holocene soils of many arid regions. Comparison of the compositions and influx rates of modern dust with the eolian component of dated soils at 24 sites in southern Nevada and California yields information on: (1) the composition and influx rate of dust in late Pleistocene and Holocene soils, (2) paleoclimate and its effects on the genesis of aridic soils, especially with regard to "dust events", (3) the timing and relative contribution of dust from playa sources versus alluvial sources, and (4) the effects of accumulation of fines in soil horizons. The A and B horizons of soils formed on gravelly alluvial-fan deposits in the study area are similar to modern dust in grain size, content of CaCO3 and salt, major oxides, and clay mineralogy; thus, they are interpreted to consist largely of eolian dust. The major-oxide compositions of the shallow soil horizons are nearly identical to that of the modern dust, but the compositions of progressively deeper horizons approach that of the parent material. The clay mineralogy of modern dust at a given site is similar to that of the Av horizons of nearby Holocene soils, but is commonly different from the mineralogies of deeper soil horizons and of the Av horizons of nearby Pleistocene soils. These results are interpreted to indicate that (1) dust both accumulates and is transformed in Av horizons with time, and (2) that clay minerals can be transformed in only 10,000 years or less. Changes in soil-accumulation rates provide insights into the interplay of paleoclimate, dust supply, and soil-forming processes. Modern dust-deposition rates are more than large enough to account for middle and late Holocene soil-accumulation rates at nearly all sites. However, the early Holocene soil-accumulation rates in areas near late Pleistocene pluvial lakes are much higher than modern rates and clearly indicate a dust-deflation and -deposition event that caused rapid formation of fine-grained shallow soil horizons on late Pleistocene and early Holocene deposits. We interpret late Pleistocene soil-accumulation rates to indicate that dust-deposition rates were low during this period but that increased effective moisture during the late Wisconsin favored translocation of clay and CaCO3 from the surface to deeper in the soil profile. Calculated pre-late Pleistocene rates are very low in most areas, mainly due to a pedogenic threshold that was crossed when accumulations of silt, clay, and CaCO3 began to inhibit the downward transport of eolian material, but in part due to erosion. Purpose: The presence of eolian dust in soils and the relative contribution of dust to soil formation in both arid and humid areas has been debated for decades. Most researchers now agree that dust is a ubiquitous component of soils formed in arid areas, although some argue that calcareous dust does not contribute significantly to the content of pedogenic calcium carbonate in some localities. Detailed studies of dust influx facilitate studies of paleoclimate based on modelling of soil-forming processes such as translocation of pedogenic carbonate. Most research on the eolian component of soils has focused on identifying the presence of dust and estimating its proportion relative to soil parent materials and in-situ weathering products. Despite general agreement on the importance of dust to soil genesis, few studies have compared modern rates of dust deposition to estimated amounts of dust in soils of known age to compare the compositions and deposition rates of modern dust to dust in soils. Quantitative comparisons are important to studies of soil genesis, paleoclimatic reconstruction from soil properties, and soil chronosequences used to estimate the ages of surfaces and deposits. For example, soils that formed downwind of a large dust source may be significantly better developed than soils of the same age that formed in sheltered areas. A project to study modern dust deposition in southern Nevada and California was initiated in 1984 to provide data on modern dust composition and influx rates for use in a numerical model relating soil carbonate to paleoclimate and in soil-chronosequence studies in the southern Great Basin and Mojave Desert (fig. 1) in support of tectonic and stratigraphic investigations for the Yucca Mountain Project. In this paper, we relate the composition of modern dust to soil properties and compare modern rates of dust influx with late Pleistocene and Holocene rates estimated from soils at 24 sites in southern Nevada and California. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: cc1000000 Ending_Date: Present Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -117.45 East_Bounding_Coordinate: -114.11 North_Bounding_Coordinate: 38.18 South_Bounding_Coordinate: 32.78 Keywords: Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: soil Theme_Keyword: pedogenesis Theme_Keyword: dust Theme_Keyword: eolian Theme_Keyword: arid Theme_Keyword: accumulation rate Place: Place_Keyword_Thesaurus: None Place_Keyword: Nevada Place_Keyword: California Place_Keyword: United States of America Place_Keyword: Western United States Place_Keyword: Kyle Canyon Place_Keyword: Silver Lake Place_Keyword: Wilson Creek Place_Keyword: Yucca Mountain Place_Keyword: Cima fans Place_Keyword: Coyote Mountains Place_Keyword: Whipple Mountains Place_Keyword: Fortymile Wash Place_Keyword: Yucca Wash Place_Keyword: Alverson Canyon Place_Keyword: Fossil Canyon Temporal: Temporal_Keyword_Thesaurus: None Temporal_Keyword: Quaternary Temporal_Keyword: Pleistocene Temporal_Keyword: Holocene Temporal_Keyword: Recent Access_Constraints: None Use_Constraints: None Point_of_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Reheis, Marith C. Contact_Organization: U. S. Geological Survey Contact_Position: Geologist Contact_Address: Address_Type: mailing address Address: Mail Stop 980 U.S. Geological Survey Box 25046, Denver Federal Center City: Denver State_or_Province: Colorado Postal_Code: 80225-0046 Country: United States of America Contact_Voice_Telephone: 303-236-1270 Contact_Electronic_Mail_Address: Security_Information: Security_Classification_System: None Security_Classification: Unclassified Security_Handling_Description: None Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Age determination of studied soils. The ages of the soils sampled for this study (11H, 11P, etc.) were estimated from field morphologic data using the soil development index. The index values were compared with values for soils of known age that formed under similar conditions of climate and, where possible ,parent material (Taylor, 1986.i.Taylor, 1986;; Reheis and others, 1989.i.Reheis and others, 1989;, 1992.i.Reheis and others, 1992; Harden and others, 1991a; Slate, 1992.i.Slate, 1992;), and "best" ages and age ranges were assigned to th esoil profiles. Harden and others (1991b).i.Harden and others (1991);, using a statistically based version of this technique in a study of soil chronosequences in the southern Great Basin (some of the sites used in this study), suggested that average rates of most soil-development parameters within this area are precise to about a factor of two and that, at least for Holocene soils, estimated ages derived from these rates might be accurate within about a factor of two or three. Laboratory Analyses. Most of the samples were analyzed using standard laboratory techniques (Singer and Janitzky, 1986.i.Singer and Janitzky, 1986;) for grain size, CaCO3 and organic-matter content, pH, and salt content, except that the total salt equations in Singer and Janitzky, published with an error, were corrected using a multiplication factor of 0.32 rather than 320. pH for the soils sampled specifically for this study was measured in 1:1 H2O, whereas the pH for soils from other sources was measured using CaCl2. Some other analytical techniques for the Kyle Canyon soils were also different because the soils formed in carbonate-rich alluvium. The contents of CaCO3 and silt plus clay reported in this table were measured using a combination of chemical, microscopic, and photographic techniques (Sowers, 1988; Reheis et al., 1992) and are the amounts of pedogenic (non-parent material) carbonate and silt plus clay, not total amounts. In addition, the salt content reported for Kyle Canyon soils is for gypsum only, not total salt. Determination of profile weights of soil components. In this study, we assume that the dust component of soils is pedogenic, not parent material, and that all silt, clay, and CaCO3 present in greater proportions in a soil than in the parent material is pedogenic material and ultimately derived from dust. Soils that formed in carbonate alluvium are one exception; they contain abundant CaCO3 derived from solution of the parent material (Sowers, 1985; Reheis and others, 1992). The major-oxide composition and clay mineralogy of the dust and soil horizons support this assumption. Previous work in the study area (McFadden, 1982; McFadden and others, 1986; Taylor, 1986; Reheis and others, 1989, 1992) indicated little chemical weathering in soils of this age. Soils that are more than about 100,000 years old or that formed in semiarid to subhumid climates have likely been chemically weathered. However, much of the silt, clay, and CaCO3 in older aridic soils is likely to be of eolian origin, in part transformed into other minerals or grain sizes by chemical or physical processes.Profile weights for Coyote Mountains soils (AC and FC) were recalculated from original data because profile weights given in Goodmacher and Rockwell (1990) did not account for parent-material values. Major Element Analyses In order to compare the soil analyses with those of nearby dust samples, which did not include Ca from CaCO3, the contents of major oxides in the soil samples from Kyle Canyon and Silver Lake were recalculated on a CaCO3-free basis (Wilson Creek soils contained no CaCO3). Clay Mineralogy Observed differences between the clay mineralogy of soils and dust at some sites are attributed either to clay formation within the soils, to variability not explored sufficiently because too few samples were analyzed, or to slightly different analytical procedures used for the soil and dust samples (different ion saturations, etc.). In addition, the published reports used different methods to estimate abundances of clay minerals from peak heights on X-ray diffraction traces. Bulk Density of Soil Horizons At most sites, the parent material consisted of alluvial-fan deposits, commonly debris flows. Debris flows are usually unsorted and unbedded, so the content of silt, clay, and CaCO3 in a C horizon formed in these deposits was assumed to be representative of that originally present in the other horizons. For soils at Wilson Creek that formed in fluvial deposits potentially containing fine-grained overbank sediment (Harden and Matti, 1989), amounts of silt and clay in the parent material of the A and B horizons were estimated to be greater than those in the C horizons. Basalt flows were assumed to contain no silt, clay, or CaCO3 when deposited. Soil Accumulation Rates Soil accumulation rates must be treated with caution for the following reasons: (1) Variation in amount of a pedogenic material is expectable for soils of the same age because soils are inherently variable. Data from more than one profile per geomorphic surface is critical for quantitative soil studies (e.g. data for field properties of soils at Silver Lake; Reheis and others, 1989). Standard deviations were only calculated for the interval rates at the Fortymile Wash area, Silver Lake, the Cima fans, Wilson Creek, and the Coyote Mountains, which had quantitative data for more than one profile per surface (file "intrtdev.xls"). Excluding soils that were strongly eroded or leached, the standard deviations average 75% of the rates, but range widely (5-200%). (2) There are uncertainties in the assigned ages of the geomorphic surfaces and their soils. This problem is most acute for the youngest deposits; for example, if a deposit is thought to be 200 years old but in fact is 400 years old, an error of only 200 years would yield a doubled accumulation rate. In addition, radiometric ages are available only for soils from Silver Lake, the Fortymile Wash area, Kyle Canyon, and the Coyote Mountains. We have not included age uncertainties in the calculation of interval rates because generally the minimum and maximum ages greatly exaggerate the probable errors. For studies in which the ages of soils were better constrained, as at Silver Lake and Fortymile Wash, interval-rate uncertainties calculated from the minimum and maximum soil ages were similar to the range of standard deviations calculated using replicate soils of the same age. (3) Assumptions and simplifications were used in the calculations of profile weights of pedogenic materials, mainly in the estimation of parent-material values and of bulk density (in this study, a range of 1.2-2.0 g/cm3), which is difficult to measure accurately in gravelly deposits (Vincent and Chadwick, 1994). Logical_Consistency_Report: Sampling Procedures This report includes the results of investigations performed by several investigators at Silver Lake, or on samples collected at Silver Lake. Two labeling standards have been followed. The first is a system which numerically encodes information about locality, unit sampled, the profile sampled and the collector of the sample. A) If the first number is 1, the sample number corresponds to a lower fan locality and 2 refers to an upper fan locality. B) The first number following the decimal represents the fan unit on which the soil was sampled: 1=Qf1, 2=Qf2, etc.; this is the same as the profile numbers elsewhere. C) The second number is the profile number on that surface in that fan position: the first described is 1, the second 2, etc. D) The last number is only used for one profile, 1.231 to 1.235, because we had five different people describe the same soil profile separately. Thus there are five descriptions of this profile but it was only sampled once. Example 1: Sample 1.110 = a sample from the lower fan area, fan unit Qf1, and is the first profile sampled. The second system is alpha numeric. A) The first set of characters indicates the locality and collection year. A label for a sample collected at Silver Lake in 1985 would begin "SL85". B) The next character indicates the position of the sample site on the fan. A, B, C, D samples are from the lower fan and W, X, Y, Z samples are from the upper fan. C) The second character indicates which profile in a sequence of profiles described in one position on the fan. A = the first profile described, B = the second profile described etc. Example 2: Sample SL85-1A = a sample from the lower fan area, fan unit Qf1, and is the first profile sampled. (it is also equal to sample 1.110 of example 1) Example 3: A sample labeled 2.340 in the numeric system equals a sample labeled SL85-3Z in the alphanumeric system and would indicate a sample from the upper fan area, from fan unit Qf3, and it would be the fourth profile sampled. Soil Descriptions Numbered profiles (11H, 11P, etc.) were sampled specifically for this study. Two profiles from San Felipe Creek (SF1 and SF3) are unpublished data contributed by Tom Rockwell (San Diego State University). Methods for the descriptions of all of the soils were the same. Soil Development Index Values The soil development index (Harden, 1982) provides a means of quantifying field properties of soils in order to compare their development. Index values of field properties including rubification, melanization, paling, lightening, texture, structure, dry consistence, pH decrease, pH increase, and carbonate are calculated for each profile using a spreadsheet template (Taylor, 1988). Horizon and profile index values are given for all of the soils sampled for this study. Laboratory Analyses Most of the samples were analyzed using standard laboratory techniques (Singer and Janitzky, 1986.i.Singer and Janitzky, 1986;) for grain size, CaCO3 and organic-matter content, pH, and salt content, except that the total salt equations in Singer and Janitzky, published with an error, were corrected using a multiplication factor of 0.32 rather than 320. pH for the soils The salt content reported for Kyle Canyon soils is for gypsum only, not total salt. Data for Kyle Canyon (KC) soils is from Reheis and others (1992). Calculation of Profile Weights The bulk density for each soil horizon, if not measured by previous reports using either the paraffin-clod method or the excavation technique, was estimated from particle size and the contents of gravel and organic matter using the technique of Rawls (1983). The contents (percentages) of soil components in each horizon were subtracted from the contents estimated to have been present in the parent material multiplied by the bulk density of the less-than-2mm fraction and by horizon thickness, and then summed for the soil. Debris flows are usually unsorted and unbedded, so the content of silt, clay, and CaCO3 in a C horizon formed in these deposits was assumed to be representative of that originally present in the other horizons. Soils at Wilson Creek that formed in fluvial deposits potentially containing fine-grained overbank sediment, amounts of silt and clay in the parent material of the A and B horizons were estimated to be greater than those in the C horizons. Basalt flows were assumed to contain no silt, clay, or CaCO3 when deposited. Major Element Analyses In order to compare the soil analyses with those of nearby dust samples, which did not include Ca from CaCO3, the contents of major oxides in the soil samples from Kyle Canyon and Silver Lake were recalculated on a CaCO3-free basis (Wilson Creek soils contained no CaCO3). Clay Mineralogy Observed differences between the clay mineralogy of soils and dust at some sites are attributed either to clay formation within the soils, to variability not explored sufficiently because too few samples were analyzed, or to slightly different analytical procedures used for the soil and dust samples (different ion saturations, etc.). In addition, the published reports used different methods to estimate abundances of clay minerals from peak heights on X-ray diffraction traces. Completeness_Report: Soil development index data (as is found in the file DSINDPRN.XLS) was generated for Silver Lake samples but is not yet ready for release. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Trap locations were ascertained by plotting their positions on USGS topographic maps at 1:24000 scale. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Amundson, R.G. Originator: Chadwick, O.A. Originator: Sowers, J.M. Originator: Doner, H.E. Publication_Date: 1989 Title: Soil evolution along an altitudinal transect in the eastern Mojave Desert of Nevada, U.S.A.: Geoderma, v. 43, p. Edition: first Series_Information: Series_Name: Geoderma Issue_Identification: volume 43 Publication_Information: Publication_Place: Amsterdam, New York Publisher: Elsevier Type_of_Source_Media: paper Source_Citation_Abbreviation: Amundson et al. (1989) Source_Contribution: Clay mineralogy data for Kyle Canyon soils. Source_Information: Source_Citation: Citation_Information: Originator: Goodmacher, J. Originator: Rockwell, T. Publication_Date: 1990 Title: Properties and inferred ages of soils developed in alluvial deposits in the southwestern Coyote Mountains, Imperial County, California, in Rockwell, T. R., ed., Friends of the Pleistocene, Winter Fieldtrip-1990, Western Salton Trough Soils and Neotectonics: San Diego, California Publication_Information: Publisher: Privately Published Publication_Place: California, USA Type_of_Source_Media: paper Source_Contribution: Soil ages and results of standard laboratory analyses of soils from the Coyote Mountains area. Source_Citation_Abbreviation: Goodmacher and Rockwell, 1990 Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: unknown Ending_Date: unknown Source_Currentness_Reference: publication date Source_Information: Source_Citation: Citation_Information: Originator: Harden, J.W. Originator: Matti, J.C. Publication_Date: 1989 Title: Holocene and late Pleistocene slip rates on the San Andreas fault in Yucaipa, California, using displaced alluvial-fan deposits and soil chronology Geospatial_Data_Presentation_Form: model Series_Information: Series_Name: Geological Society of America Bulletin Issue_Identification: volume 101 Publication_Information: Publication_Place: Kansas Publisher: Geological Society of America Type_of_Source_Media: paper Source_Citation_Abbreviation: Harden and Matti, 1989 Source_Contribution: 1) Ages of soils in similar condition and formed under similar conditions as soils discussed in this study. 2)Soil ages for the Wilson Creek locality. Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: cc1000000 Ending_Date: Present Source_Currentness_Reference: publication date Source_Information: Source_Citation: Citation_Information: Originator: Harden, J.W. Originator: Slate, J.L. Originator: Lamothe, P. Originator: Chadwick, O.A. Originator: Pendall, E.G. Originator: Gillespie, A.M. Publication_Date: 1991 Title: Soil formation on the Trail Canyon alluvial fan Series_Information: Series_Name: U.S. Geological Survey Open-File Report Issue_Identification: volume 91-291 Publication_Information: Publication_Place: Denver, Colorado Publisher: United States Geological Survey Type_of_Source_Media: paper Source_Contribution: Index values for soils of known age for comparison to material examined for this study. Source_Citation_Abbreviation: Harden and others, 1991a Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: unknown Ending_Date: unknown Source_Currentness_Reference: publication date Source_Information: Source_Citation: Citation_Information: Originator: Harden, J.W. Originator: Taylor, E.M. Originator: Hill, C. Originator: Mark, R.K. Originator: McFadden, L.D. Originator: Reheis, M.C. Originator: Sowers, J.M. Originator: Wells, S.G. Publication_Date: 1991 Title: Rates of soil development from four soil chronosequences in the southern Great Basin Series_Information: Series_Name: Quaternary Research Issue_Identification: volume 35 Type_of_Source_Media: paper Source_Contribution: Soil ages for the Cima fans study area. Source_Citation_Abbreviation: Harden and others, 1991b Source_Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: Unknown Ending_Date: Unknown Source_Currentness_Reference: publication date Source_Information: Source_Citation: Citation_Information: Originator: McFadden, L.D. Publication_Date: 1982 Title: The impacts of temporal and spatial climatic changes on alluvial soils genesis in southern California Publication_Information: Publication_Place: Tucson, Arizona Publisher: University of Arizona (Ph.D. dissertation) Type_of_Source_Media: paper Source_Time_Period_of_Content: Source_Currentness_Reference: publication date Time_Period_Information: Range_of_Dates/Times: Beginning_Date: Unknown Ending_Date: Unknown Source_Contribution: 1) Ages for soils for the Whipple Mountain locality. 2) Results of clay mineralogy analyses of Whipple Mountain soils. Source_Citation_Abbreviation: McFadden, 1982 Source_Information: Source_Citation: Citation_Information: Originator: McFadden, L.D. Originator: Wells, S.G. Originator: Dohrenwend, J.C. Publication_Date: 1986 Title: Influences of Quaternary climatic changes on processes of soil development on desert loess deposits of the Cima volcanic field, California Series_Information: Series_Name: Catena Issue_Identification: Volume 13 Type_of_Source_Media: paper Source_Citation_Abbreviation: McFadden et al., 1986 Source_Contribution: Results of analyses of clay mineralogy of Cima volcanic field soils Source_Information: Source_Citation: Citation_Information: Originator: Reheis, M.C. Originator: Harden, J.W. Originator: McFadden, L.D. Originator: Shroba, R.R. Publication_Date: 1989 Title: Development rates of late Quaternary soils, Silver Lake playa, California Series_Information: Series_Name: Soil Science Society of America Journal Issue_Identification: volume 53 Type_of_Source_Media: paper Source_Citation_Abbreviation: Reheis and others, 1989 Source_Contribution: Index values for soils of known age for comparison with material examined for this study. Source_Information: Source_Citation: Citation_Information: Originator: Reheis, M.C. Originator: Sowers, J.M. Originator: Taylor, E.M. Originator: McFadden, L.D. Originator: Harden, J.W. Publication_Date: 1992 Title: Morphology and genesis of carbonate soils on the Kyle Canyon fan, Nevada, U.S.A Series_Information: Series_Name: Geoderma Issue_Identification: volume 52 Type_of_Source_Media: paper Source_Citation_Abbreviation: Reheis and others, 1992 Source_Contribution: 1) Index values for soils of known age for comparison with material examined for this study. 2) Results of laboratory chemical analyses of sample material. 3) Results of major-element analyses for soil samples obtained from Kyle Canyon localities Source_Information: Source_Citation: Citation_Information: Originator: Sowers, J.M. Originator: Amundson, R.G. Originator: Chadwick, O.A. Originator: Harden, J.W. Originator: Jull, A.J.T. Originator: Ku, T.L. Originator: McFadden, L.D. Originator: Reheis, M.C. Originator: Szabo, B. Publication_Date: 1988 Title: Geomorphology and pedology on the Kyle Canyon alluvial fan, southern Nevada, in Weide, D.L., and Faber, M.L., eds., This Extended Land Series_Information: Series_Name: Guidebook, Geological Society of America, Issue_Identification: Cordillerian Section Meeting Type_of_Source_Media: paper Source_Citation_Abbreviation: Sowers and others, 1988 Source_Contribution: Ages of soils in the Kyle Canyon area Source_Information: Source_Citation: Citation_Information: Originator: Taylor, E.M. Publication_Date: 1986 Title: Impact of time and climate on Quaternary soils in the Yucca Mountain area of the Nevada Test Site Publication_Information: Publication_Place: Boulder Colorado Publisher: Master's thesis, University of Colorado Type_of_Source_Media: paper Source_Citation_Abbreviation: Taylor, 1986 Source_Contribution: 1) Ages of soils comparable to those included in this study. 2) Clay mineralogy of soils from the Forty-Mile Wash area. Process_Step: Process_Description: Sampling and Description. In each area, two alluvial-fan surfaces were selected that were thought to be late Pleistocene and middle to late Holocene in age by comparison of surface characteristics such as pavement, varnish, and preservation of depositional topography to those of dated surfaces from previous studies in the region (for example, McFadden and others, 1989; Reheis and others, 1993.i.Reheis, 1992;). One soil profile was described and sampled on each surface using either fresh stream cuts or hand-dug pits. Soil descriptions and horizon names followed Guthrie and Witty (1982) and Birkeland (1984). Stages of CaCO3 , silica, and salt follow definitions of Gile and others (1966), Taylor (1986), and Reheis (1987), respectively. Process_Date: 1995 Process_Step: Process_Description: The soil development index (Harden, 1982) provides a means of quantifying field properties of soils in order to compare their development. Index values of field properties including rubification, melanization, paling, lightening, texture, structure, dry consistence, pH decrease, pH increase, and carbonate (Harden, 1982; Reheis, 1987; Harden and others, 1991b) are calculated for each profile using a spreadsheet template (Taylor, 1988). Normalized values of these properties are multiplied by horizon thickness to obtain the horizon index; the horizon values within a profile are summed to obtain the profile index. Horizon and profile index values are given for all of the soils sampled for this study. Process_Date: 1995 Process_Step: Process_Description: Laboratory Analyses. Most of the samples were analyzed using standard laboratory techniques (Singer and Janitzky, 1986.i.Singer and Janitzky, 1986;) for grain size, CaCO3 and organic-matter content, pH, and salt content, except that the total salt equations in Singer and Janitzky, published with an error, were corrected using a multiplication factor of 0.32 rather than 320. pH for the soils sampled specifically for this study was measured in 1:1 H2O, whereas the pH for soils from other sources was measured using CaCl2. Some other analytical techniques for the Kyle Canyon soils were also different because the soils formed in carbonate-rich alluvium. Process_Date: 1995 Process_Step: Process_Description: Bulk Density of Soil Horizons The bulk density for each soil horizon, if not measured by previous reports using either the paraffin-clod method or the excavation technique, was estimated from particle size and the contents of gravel and organic matter using the technique of Rawls (1983).i.Rawls (1983);.Profile weights (g/cm2/soil column) were calculated for pedogenic silt, clay, CaCO3, and salt (where possible). The contents (percentages) of these components in each horizon of a soil were subtracted from the contents estimated to have been present in the parent material (method of Machette, 1985), multiplied by the bulk density of the less-than-2mm fraction and by horizon thickness, and then summed for the soil. Process_Date: 1995 Process_Step: Process_Description: Calculation of Accumulation Rates. Accumulation rates were calculated for pedogenic silt, clay, CaCO3, and salt depending on the availability of data. At sites with more than one analyzed soil profile of the same age, the profile-weight values were averaged. The average "best" accumulation rates were calculated using the "best" age (the most reasonable age assigned to the geomorphic surface), and average maximum and minimum rates were calculated using the likely minimum and maximum ages respectively. The following are example calculations for the silt accumulation rate of soils on surface Q5, Coyote Mountains, where the average profile weight of silt in Q5 soils is 0.8 g/cm2, the "best" age is 12 ka, the minimum age is 9 ka, and the maximum age is 20 ka: average "best" accumulation rate = 0.8 g/cm2 / 12,000 yr = 0.7 g/m2/yr average maximum accum. rate = 0.8 g/cm2 / 9,000 yr = 0.9 g/m2/yr average minimum accum. rate = 0.8 g/cm2 / 20,000 yr = 0.4 g/m2/yr Process_Date: 1995 Process_Step: Process_Description: Calculation of the Interval Accumulation Rate. The interval-accumulation rate for each profile is the rate of accumulation of a pedogenic component in a soil forming on a surface from the time of deposition of that surface to the time of deposition of the next younger surface. If there is no younger profile, the interval rate is the same as the average rate. Interval age is the period of time between the formation of one surface and the formation of the next younger surface. Best interval age = best age (older) - best age (younger). Minimum interval age = minimum age (older) - maximum age (younger). Maximum interval age = maximum age (older) - minimum age (younger). Process_Date: 1995 Spatial_Data_Organization_Information: Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.01 Longitude_Resolution: 0.01 Geographic_Coordinate_Units: Decimal degrees Vertical_Coordinate_System_Definition: Altitude_System_Definition: Altitude_Datum_Name: North American Vertical Datum of 1988 Altitude_Resolution: 1 Altitude_Distance_Units: meters Altitude_Encoding_Method: Explicit elevation coordinate included with horizontal coordinates Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: This data set contains 262 distinct attributes. Documenting these attributes using the detailed form of the Content Standards for Digital Geospatial Metadata is possible in principle but not practical due to time constraints. Core/meta/averate.txt Column 1 Area Column 2 Dust Trap Column 3 surface (no. for ave.) Column 4 Age, Best Column 5 Age, Min Column 6 Age, Max Column 7 Prof. Mass, Silt, (g/cm2/soil col.) Silt Column 8 Prof. Mass, Clay, (g/cm2/soil col.) Clay Column 9 Prof. Mass, CaCO3, (g/cm2/soil col.) CaCO3 Column 10 Prof. Mass, Salt, (g/cm2/soil col.) Salt Column 11 Silt, Best Column 12 Silt, Max Column 13 Silt, Min Column 14 Clay, Best Column 15 Clay, Max Column 16 Clay, Min Column 17 CaCO3, Best Column 18 CaCO3, Max Column 19 CaCO3, Min Column 20 Salt, Best Column 21 Salt, Max Column 22 Salt, Min Core/meta/dsindrpn.txt Column 1 Sample number Column 2 Horizon Column 3 Thickness, (cm) Column 4 Rubification, Norm. value Column 5 Rubification, Horizon value Column 6 Rubification, Profile value Column 7 Melanization, Norm. value Column 8 Melanization, Horizon value Column 9 Melanization, Profile value Column 10 Paling, Norm. value Column 11 Paling, Horizon value Column 12 Paling, Profile value Column 13 Lightening, Norm. value Column 14 Lightening, Horizon value Column 15 Lightening, Profile value Column 16 Total, Texture Norm. value Column 17 Total, Texture Horizon value Column 18 Total, Texture Profile value Column 19 Structure, Norm. value Column 20 Structure, Horizon value Column 21 Structure, Profile value Column 22 Dry Consistence, Norm. value Column 23 Dry Consistence, Horizon value Column 24 Dry Consistence, Profile value Column 25 Clay Films, Norm. value Column 26 Clay Films, Horizon value Column 27 Clay Films, Profile value Column 28 Carbonate, Norm. value Column 29 Carbonate, Horizon value Column 30 Carbonate, Profile value Column 31 pH decrease, Norm. value Column 32 pH decrease, Horizon value Column 33 pH decrease, Profile value Column 34 pH increase, Norm. value Column 35 pH increase, Horizon value Column 36 pH increase, Profile value Column 37 Profile Index 1, Norm. value (rb, ml, tx, st, dc, cf, pHde) Column 38 Profile Index 1, Horizon value (rb, ml, tx, st, dc, cf, pHde) Column 39 Profile Index 1, Profile value (rb, ml, tx, st, dc, cf, pHde) Column 40 Profile Index 2, Norm. value (pl, lt, tx, st, dc, cf, pHin) Column 41 Profile Index 2, Horizon value (pl, lt, tx, st, dc, cf, pHin) Column 42 Profile Index 2, Profile value (pl, lt, tx, st, dc, cf, pHin) Column 43 Profile Index 3, Norm. value (pl, lt, tx, st, dc, cf, pHin) Column 44 Profile Index 3, Horizon value (pl, lt, tx, st, dc, cf, pHin) Column 45 Profile Index 3, Profile value (pl, lt, tx, st, dc, cf, pHin) Core/meta/dsolab.txt Column 1 Sample number Column 2 Profile number Column 3 Horizon name Column 4 Depth to base (cm) Column 5 Gravel content, Est. vol.% Column 6 Gravel content, Weight% Column 7 pH Column 8 Weight percent of less-than-2mm fraction O.M. Column 9 Weight percent of less-than-2mm fraction Sand Column 10 Weight percent of less-than-2mm fraction Silt@ Column 11 Weight percent of less-than-2mm fraction Clay Column 12 Weight percent of less-than-2mm fraction CaCO3* Column 13 Weight percent of less-than-2mm fraction Salt** Core/meta/dsoldes.txt Column 1 Surface / Elevation (m)/ age Column 2 Profile / Describer(s) Column 3 Sample / Number Column 4 Horizon Column 5 Boundary Depth (cm) top Column 6 Boundary Depth (cm) base Column 7 Boundary nature Column 8 Matrix Color #1, Dry Column 9 Matrix Color #1, Moist Column 10 Carbonate Color #2, Dry Column 11 Carbonate Color #3, Dry Column 12 Carbonate Color #4, Dry Column 13 Texture Column 14 Structure, Primary Column 15 Structure, Secondary Column 16 Consistence, Dry Column 17 Consistence, Wet Column 18 Clay films, Primary Column 19 Clay films, Secondary Column 20 CaCO3 Matrix Column 21 CaCO3 Gravel Column 22 % gravel <2 mm Column 23 Parent material and lithology Column 24 Roots Column 25 Pores Column 26 SiO2 Column 27 Salt Column 28 Miscellaneous notes Core/meta/dsolloc.txt Column 1 Soil-study site(&) Column 2 Source of soil data (@) Column 3 Parent material type* Column 4 Parent material lithology Column 5 Trap (T-) Column 6 Trap latitude Column 7 Trap longitude Column 8 Trap elevation Column 9 est. (+) MAT (±1.3C) Column 10 est. (+) MAP (cm) Core/meta/dsolmin.txt Column 1 Area Column 2 Profile Column 3 Best age (ka) Column 4 Horizon Column 5 Chlorite Column 6 Kaolinite Column 7 Mica Column 8 Vermiculite Column 9 Smectite Column 10 Mixed-layer Column 11 Palygorskite Column 12 Quartz Core/meta/dsolox.txt Column 1 Profile no. Column 2 Horizon Column 3 Percent SiO2 Column 4 Percent Al2O3 Column 5 Percent Fe2O3 Column 6 Percent FeO Column 7 Percent MgO Column 8 Percent CaO Column 9 Percent Na2O Column 10 Percent K2O Column 11 Percent TiO2 Column 12 Percent P2O5 Column 13 Percent MnO Column 14 Percent ZrO2 Column 15 factor Column 16 Percent oxides recalculated to 100%, SiO2 Column 17 Percent oxides recalculated to 100%, Al2O3 Column 18 Percent oxides recalculated to 100%, Fe2O3 Column 19 Percent oxides recalculated to 100%, FeO Column 20 Percent oxides recalculated to 100%, MgO Column 21 Percent oxides recalculated to 100%, CaO Column 22 Percent oxides recalculated to 100%, Na2O Column 23 Percent oxides recalculated to 100%, K2O Column 24 Percent oxides recalculated to 100%, TiO2 Column 25 Percent oxides recalculated to 100%, P2O5 Column 26 Percent oxides recalculated to 100%, MnO Column 27 Percent oxides recalculated to 100%, ZrO2 Column 28 Percent CaCO3 Column 29 Percent CaO in CaCO3 Column 30 iterations factor 1 Column 31 factor 2 Column 32 Percent recalculated with CaO due to CaCO3 removed, SiO2 Column 33 Percent recalculated with CaO due to CaCO3 removed, Al2O3 Column 34 Percent recalculated with CaO due to CaCO3 removed, Fe2O3 Column 35 Percent recalculated with CaO due to CaCO3 removed, FeO Column 36 Percent recalculated with CaO due to CaCO3 removed, MgO Column 37 Percent recalculated with CaO due to CaCO3 removed, CaO Column 38 Percent recalculated with CaO due to CaCO3 removed, Na2O Column 39 Percent recalculated with CaO due to CaCO3 removed, K2O Column 40 Percent recalculated with CaO due to CaCO3 removed, TiO2 Column 41 Percent recalculated with CaO due to CaCO3 removed, P2O5 Column 42 Percent recalculated with CaO due to CaCO3 removed, MnO Column 43 Percent recalculated with CaO due to CaCO3 removed, ZrO2 Column 44 Sum Core/meta/dsolpw.txt Column 1 Sample number Column 2 Profile number Column 3 Horizon name Column 4 Thickness (cm.) Column 5 Gravel content vol.% Column 6 Gravel content wt.% Column 7 Organic matter Column 8 Silt content of less-than-2mm fraction (weight %) lab Column 9 Silt content of less-than-2mm fraction (weight %) PM Column 10 Clay content of less-than-2mm fraction (weight %) lab Column 11 Clay content of less-than-2mm fraction (weight %) PM Column 12 CaCO3 content of less-than-2mm fraction (weight %) lab Column 13 CaCO3 content of less-than-2mm fraction (weight %) P.M Column 14 Salt content of less-than-2mm fraction (weight %) lab Column 15 Salt content of less-than-2mm fraction (weight %) P.M. Column 16 Assigned mineral B.D., min Column 17 Assigned mineral B.D., max Column 18 Calculated B.D. of soil, min Column 19 Calculated B.D. of soil, max Column 20 Calculated < 2mm B.D., min Column 21 Calculated < 2mm B.D., max Column 22 Change from parent material, (weight percent) silt Column 23 Change from parent material, (weight percent) clay Column 24 Change from parent material, (weight percent) CaCO3 Column 25 Change from parent material, (weight percent) salt Column 26 Pedogenic silt, Horizon, min Column 27 Pedogenic silt, Horizon, max Column 28 Pedogenic silt, Profile sum, min Column 29 Pedogenic silt, Profile sum, max Column 30 Pedogenic clay, Horizon, min Column 31 Pedogenic clay, Horizon, max Column 32 Pedogenic clay, Profile sum, min Column 33 Pedogenic clay, Profile sum, max Column 34 Pedogenic CaCO3, Horizon, min Column 35 Pedogenic CaCO3, Horizon, max Column 36 Pedogenic CaCO3, Profile sum, min Column 37 Pedogenic CaCO3, Profile sum, max Column 38 Pedogenic salt, Horizon, min Column 39 Pedogenic salt, Horizon, max Column 40 Pedogenic salt, Profile sum, min Column 41 Pedogenic salt, Profile sum, max Core/meta/intrate.txt Column 1 soils Column 2 trap Column 3 Assigned age, best Column 4 Assigned age, min Column 5 Assigned age, max Column 6 Interval age, best Column 7 Interval age, min Column 8 Interval age, max Column 9 Silt mass, (g/cm2/col), total Column 10 Silt mass, (g/cm2/col), interval Column 11 Silt interval rate,(g/m2/yr), best Column 12 Silt interval rate,(g/m2/yr), max Column 13 Silt interval rate, (g/m2/yr), min Column 14 Clay mass, (g/cm2/col), total Column 15 Clay mass, (g/cm2/col), interval Column 16 Clay interval rate, (g/m2/yr), best Column 17 Clay interval rate, (g/m2/yr), max Column 18 Clay interval rate, (g/m2/yr), min Column 19 CaCO3 mass, (g/cm2/col), total Column 20 CaCO3 mass, (g/cm2/col), interval Column 21 CaCO3 interval rate, (g/m2/yr), best Column 22 CaCO3 interval rate, (g/m2/yr), max Column 23 CaCO3 interval rate, (g/m2/yr), min Column 24 Salt mass, (g/cm2/col), total Column 25 Salt mass, (g/cm2/col), interval Column 26 Salt interval rate, (g/m2/yr), best Column 27 Salt interval rate, (g/m2/yr), max Column 28 Salt interval rate, (g/m2/yr), min Core/meta/intrtdev.txt Column 1 soils Column 2 best age Column 3 int. age Column 4 Silt mass, (g/cm2/col), total Column 5 Silt mass, (g/cm2/col), interval Column 6 Silt interval rate, (g/m2/yr), rate Column 7 Silt interval rate, s.d. Column 8 Clay mass, (g/cm2/col), total Column 9 Clay mass, (g/cm2/col), interval Column 10 Clay interval rate, (g/m2/yr), rate Column 11 Clay interval rate, s.d. Column 12 CaCO3 mass, (g/cm2/col), total Column 13 CaCO3 mass, (g/cm2/col), interval Column 14 CaCO3 interval rate, (g/m2/yr), rate Column 15 CaCO3 interval rate, s.d. Column 16 Salt mass, (g/cm2/col), total Column 17 Salt mass, (g/cm2/col), interval Column 18 Salt interval rate, (g/m2/yr), rate Column 19 Salt interval rate, s.d. Entity_and_Attribute_Detail_Citation: Further explaination of the data represented in individual files is found in the file /Core/meta/dsolproc.txt dsolproc. txt. Footnotes on data fields are found in the file /Core/meta/ dsolfoot.txt. Distribution_Information: Distributor: Contact_Information: Contact_Person_Primary: Contact_Person: Kevin M. Foley Contact_Organization: Global Climate History Program, U.S. Geological Survey Contact_Address: Address_Type: mailing address Address: Mail Stop 906 U.S. Geological Survey 12201 Sunrise Valley Drive City: Reston State_or_Province: Virginia Postal_Code: 20192 Contact_Voice_Telephone: (703) 648-5285 Contact_Facsimile_Telephone: (703) 648-6647 Contact_Electronic_Mail_Address: kfoley@usgs.gov Resource_Description: U.S. Geological Survey Open-File Report 95-1 Distribution_Liability: This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: TEXT Format_Information_Content: The information is structured and formatted for retrieval using WWW browsers. Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: Network_Resource_Name: Online_Computer_and_Operating_System: Data General AViiON 6220 system running DG/UX version 5.4R3.10 (UNIX) Fees: none Metadata_Reference_Information: Metadata_Date: 19961001 Metadata_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Kevin M. Foley Contact_Address: Address_Type: mailing address Address: Mail Stop 906 U.S. Geological Survey 12201 Sunrise Valley Drive City: Reston State_or_Province: VA Postal_Code: 20192 Contact_Voice_Telephone: (703) 648-5285 Contact_Facsimile_Telephone: (703) 648-6647 Contact_Electronic_Mail_Address: kfoley@usgs.gov Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: 19940604