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Ghost-dune hollows on the eastern Snake River Plain (ESRP), Idaho, USA, are topographically inverted, crescent-shaped depressions that record the partial encasement of sand dunes by ca. 61 ka basalt lava flows. Deflation of these “ghost” sand dunes produced approximately two dozen, 5–10-m-deep ghost-dune hollows now incompletely filled with pedogenically altered eolian and colluvial sediment. Optically stimulated luminescence (OSL) and 40Ar/39Ar ages constrain a ghost-dune hollow model that illuminates the late Pleistocene to Holocene environmental and climate history of the ESRP. Detrital zircon analyses indicate sand-dune supply routes changed following the burial of Pleistocene Henrys Fork (tributary of the Snake River) alluvium by ca. 70 ka basalt flows. Removal of Henrys Fork alluvium from the eolian supply system made Lake Terreton sediment the primary source for later ESRP sand dunes. Such sediment supply changes highlight the potential impacts of effusive volcanism on sand-dune histories and landscapes. Our results support stratigraphic and sedimentary modeling of comparable ghost-dune 舠pit舡 deposits older than ca. 2 Ga on Mars that may have served as refugia for early life on that planet. Analogous ancient ghost-dune hollow deposits on Earth may also have served as early life refugia.

Approximately 2 km2 of sand- and gravel-rich Pleistocene glacial-outburst megaflood sediment has accumulated in a series of five subparallel paleochannels that are an important component of a basalt-dominated aquifer system on the semiarid, ~450-km2 West Plains area. Located near Spokane, Washington (USA), the West Plains paleochannel deposits have been used for artificial storage and recovery wells and for planned and passive stormwater disposal in this rapidly growing area. Recent recognition of perfluorooctanoic acid contamination and excessive drawdowns have led to the closure of multiple municipal wells on the West Plains, highlighting the challenges of developing a sustainable groundwater supply in this complex aquifer system. Geologic and hydrogeologic data, from more than 1,400 water-well reports, surface exposures, existing groundwater geochemistry reports, and modeling, reveal the interconnections between the paleochannel deposits and surrounding basalt flows in three dimensions (3D). Initially incised into the Miocene Columbia River Basalt and excavated by Pleistocene glacial-outburst megaflooding, the West Plains paleochannels are projected in unprecedented 3D. This study’s modeled interactions between the more highly hydraulically conductive (100×) paleochannel sedimentary deposits and surrounding basalt beds provide insight into 14C ages and tritium values that had been measured previously. Sediment-filled closed depressions at the bases of the paleochannels, which are features likely formed by turbulent bursts (‘kolks’) during peak megaflood flows, are potentially promising groundwater storage sites. However, because of the relatively higher permeability of the unconfined paleochannel deposits, the closed depressions also are potential conduits for infiltration of contamination to deeper parts of the aquifer system.

Proteins are critical in catalyzing chemical reactions, forming key cellular structures, and in regulating cellular processes. Investigation of marine microbial proteins by metaproteomics methods enables the discovery of numerous aspects of microbial biogeochemistry processes. However, these datasets present big-data challenges as they often involve many samples collected across broad geospatial and temporal scales, resulting in thousands of protein identifications, abundances, and corresponding annotation information. The Ocean Protein Portal (OPP) was created to enable data sharing and discovery among multiple scientific domains and serve both research and education functions. The portal focuses on three use case questions: “Where is my protein of interest?”, “Who makes it?”, and “How much is there?”, and provides profile and section visualizations, real-time taxonomic analysis, and links to metadata, sequence analysis, and other external resources to enabling connections to be made between biogeochemical and proteomics datasets.

We present METATRYP version 2 software that identifies shared peptides across the predicted proteomes of organisms within environmental metaproteomics studies to enable accurate taxonomic attribution of peptides during protein inference. Improvements include ingestion of complex sequence assembly data categories (metagenomic and metatranscriptomic assemblies, single cell amplified genomes, and metagenome assembled genomes), prediction of the least common ancestor (LCA) for a peptide shared across multiple organisms, increased performance through updates to the backend architecture, and development of a web portal (https://metatryp.whoi.edu). Major expansion of the marine METATRYP database with predicted proteomes from environmental sequencing confirms a low occurrence of shared tryptic peptides among disparate marine microorganisms, implying tractability for targeted metaproteomics. METATRYP was designed to facilitate ocean metaproteomics and has been integrated into the Ocean Protein Portal (https://oceanproteinportal.org); however, it can be readily applied to other domains. We describe the rapid deployment of a coronavirus-specific web portal (https://metatryp-coronavirus.whoi.edu/) to aid in use of proteomics on coronavirus research during the ongoing pandemic. A coronavirus-focused METATRYP database identified potential SARS-CoV-2 peptide biomarkers and indicated very few shared tryptic peptides between SARS-CoV-2 and other disparate taxa analyzed, sharing

We present METATRYP version-2 software that identifies shared peptides across organisms within environmental metaproteomics studies to enable accurate taxonomic attribution of peptides during protein inference. Improvements include: ingestion of complex sequence assembly data categories (metagenomic and metatranscriptomic assemblies, single cell amplified genomes, and metagenome assembled genomes), prediction of the Least Common Ancestor (LCA) for a peptide shared across multiple organisms, increased performance through updates to the backend architecture, and development of a web portal (https://metatryp.whoi.edu). Major expansion of the marine database confirms low occurrence of shared tryptic peptides among disparate marine microorganisms, implying tractability for targeted metaproteomics. METATRYP was designed for ocean metaproteomics and has been integrated into the Ocean Protein Portal (https://oceanproteinportal.org); however, it can be readily applied to other domains. We describe the rapid deployment of a coronavirus-specific web portal (https://metatryp-coronavirus.whoi.edu/) to aid in use of proteomics on coronavirus research during the ongoing pandemic. A Coronavirus-focused METATRYP database identified potential SARS-CoV-2 peptide biomarkers and indicated very few shared tryptic peptides between SARS-CoV-2 and other disparate taxa, sharing 0.1% peptides or less (1 peptide) with the Influenza A & B pan-proteomes, establishing that taxonomic specificity is achievable using tryptic peptide-based proteomic diagnostic approaches.Statement of significanceWhen assigning taxonomic attribution in bottom-up metaproteomics, the potential for shared tryptic peptides among organisms in mixed communities should be considered. The software program METATRYP v 2 and associated interactive web portals enables users to identify the frequency of shared tryptic peptides among taxonomic groups and evaluate the occurrence of specific tryptic peptides within complex communities. METATRYP facilitates phyloproteomic studies of taxonomic groups and supports the identification and evaluation of potential metaproteomic biomarkers.

Ocean metaproteomics is an emerging field enabling discoveries about marine microbial communities and their impact on global biogeochemical processes. Recent ocean metaproteomic studies have provided insight into microbial nutrient transport, colimitation of carbon fixation, the metabolism of microbial biofilms, and dynamics of carbon flux in marine ecosystems. Future methodological developments could provide new capabilities such as characterizing long-term ecosystem changes, biogeochemical reaction rates, and in situ stoichiometries. Yet challenges remain for ocean metaproteomics due to the great biological diversity that produces highly complex mass spectra, as well as the difficulty in obtaining and working with environmental samples. This review summarizes the progress and challenges facing ocean metaproteomic scientists and proposes best practices for data sharing of ocean metaproteomic data sets, including the data types and metadata needed to enable intercomparisons of protein distributions and annotations that could foster global ocean metaproteomic capabilities.

The St. Anthony Dune Field (SADF) is a ~300 km2 expanse of active to stabilized transverse, barchan, barchanoid, and parabolic sand dunes located in a semi-arid climate in southeastern Idaho. The northeastern portion of the SADF, ~16 km2, was investigated to examine meteorological influences on dune mobility. Understanding meteorological predictors of sand-dune migration for the SADF informs landscape evolution and impacts assessment of eolian activity on sensitive agricultural lands in the western United States, with implications for semi-arid environments globally. Archival aerial photos from 1954 to 2011 were used to calculate dune migration rates which were subsequently compared to regional meteorological data, including temperature, precipitation and wind speed. Observational analyses based on aerial photo imagery and meteorological data indicate that dune migration is influenced by weather for up to 5–10 years and therefore decadal weather patterns should be taken into account when using dune migration rates as proxies from climate fluctuation. Statistical examination of meteorological variables in this study indicates that 24% of the variation of sand dune migration rates is attributed to temperature, precipitation and wind speed, which is increased to 45% when incorporating lag time.

The Kulshan caldera formed at ∼1.15 Ma on the present-day site of Mt. Baker, Washington State, northwest USA and erupted a compositionally zoned (dacite-rhyolite) magma and a correlative eruptive, the Lake Tapps tephra. This tephra has previously been described, but only from the Puget Lowland of NW Washington. Here an occurrence of a Kulshan caldera correlative tephra is described from the Quaternary Palouse loess at the Washtucna site (WA-3). Site WA-3 is located in east-central Washington, ∼340 km southeast of the Kulshan caldera and ∼300 km east-southeast of the Lake Tapps occurrence in the Puget Lowland. Major- and trace element chemistry and location of the deposit at Washtucna within reversed polarity sediments indicates that it is not correlative with the Mesa Falls, Rockland, Bishop Ash, Lava Creek B or Huckleberry Ridge tephras. Instead the Washtucna deposit is related to the Lake Tapps tephra by fractional crystallisation, but is chemically distinct, a consequence of its eruption from a compositionally zoned magma chamber. The correlation of the Washtucna occurrence to the Kulshan caldera-forming eruption indicates that it had an eruptive volume exceeding 100 km3, and that its tephra could provide a valuable early-Pleistocene chronostratigraphic marker in the Pacific Northwest.

The Maitahi Formation is a large-volume (>7.5 km 3 ) debris-avalanche deposit that resulted from a mid-Pleistocene (ca. 0.24–0.21 Ma) collapse of Pouakai Volcano, Taranaki Peninsula, New Zealand. It is best exposed at intermediate distances (12–14 km) from its source and consists of heterolithologic megaclast-rich and megaclast-poor facies. There are four megaclast and clast types: (1) volcanogenic sedimentary deposits derived from the cone and ring plain; (2) extrusive and intrusive igneous rocks derived primarily from the cone; (3) Pliocene mudstone-rich, subedifice bedrock; and (4) pyroclastic deposits derived from the cone and ring plain. Transport of intact, weakly to moderately lithified, volcanogenic sedimentary and bedrock megaclasts and megaclast domains, tens of meters in diameter, indicates that the W-NW–directed Maitahi debris avalanche was dominantly viscous and nonturbulent. Normally faulted, stratified megaclasts reflect flow dilation, whereas jigsaw-puzzle fractured megaclasts and clasts are evidence for early-stage compression and limited particle-particle and particle-substrate collisions. Folded and elongated megaclasts and clasts and injected interclast matrix reflect the influences of syn- and postavalanche compression, loading, penetrative shear, and pore-fluid overpressures. A significant subedifice bedrock and ring-plain megaclast and clast content distinguishes the Maitahi Formation from all other Taranaki Peninsula debris-avalanche deposits. Coupled with its large volume, the subedifice bedrock content also suggests that the Maitahi Formation originated from a deep-seated edifice collapse, unlike subsequent, and apparently shallower, edifice collapses at the nearby and genetically similar Egmont Volcano.

Sedimentologic, stratigraphic, and pedologic evidence demonstrates that Eureka Flat (EF), a narrow, 80-km-long deflation plain in south-central Washington, USA, is the source for the thick and widespread loess of the Palouse region. Located in the southern Columbia Plateau, EF has been a depocenter for abundant clay-to-sand-sized sediment derived from repeated glacial outburst floods that swept through the area during the Pleistocene. Prevailing SW winds that were funneled across EF remobilized flood sediment into sand dunes, sand sheets, and loess. An eolian sand sheet buried beneath 1.8 m of loess at the downwind end of EF attests to bioclimatically driven changes in the style of eolian deposition. The depositional transition from sand sheet to loess is characterized by a change from wind-rippled strata to structureless, bimodal sand and silt with insect burrows and rhizoliths, to unimodal sandy loess. Soil moisture and density of dust-trapping vegetation control where sand dunes and loess accumulate. Up to 4.5 m of post-LGM loess mantles the landscape adjacent to and downwind from EF. Some of the thickest loess deposits owe their origins to the sequestering of eolian sand particles by topographic traps such as the Touchet River and its tributary valleys. The removal of saltating sand from the eolian system promotes thick accumulation of loess downwind of topographic traps. Patterns of loess accumulation across the Columbia Plateau are identified on isopach maps of major pre- and post-LGM loess units and show that EF has been the major engine for the production of atmospheric dust and loess during both times.

Topographic and climatic influences have controlled thick loess accumulation at the southern margin of the Palouse loess in northern Oregon. Juniper and Cold Springs Canyons, located on the upwind flank of the Horse Heaven Hills, are oriented perpendicular to prevailing southwesterly winds. These canyons are topographic traps that separate eolian sand on the upwind side from thick accumulations (nearly 8 m) of latest Pleistocene to Holocene L1 loess on the downwind side. Silt- and sand-rich glacial outburst flood sediment in the Umatilla Basin is the source of eolian sand and loess for the region. Sediment from this basin also contributes to loess accumulations across much of the Columbia Plateau to the northeast. Downwind of Cold Springs Canyon, Mt. St. Helens set S and Glacier Peak tephras bracket 4 m of loess, demonstrating that approximately 2500 g m−2 yr−1 of loess accumulated between about 15,400–13,100 cal yr B.P. Mass accumulation rates decreased to approximately 250 g m−2 yr−1 from 13,100 cal yr B.P. to the present. Tephrochronology suggests that the bulk of near-source Palouse loess accumulated in one punctuated interval in the latest Pleistocene characterized by a dry and windy climate.

The middle Eocene White Lake and Skaha formations in the White Lake Basin, British Columbia record the sedimentary and volcanic infilling of a supradetachment basin that developed during the latter stages of Shuswap metamorphic core complex exhumation. The 1.1-km-thick White Lake Formation is characterized by volcanogenic sediment gravity flow, fluvial, and sheetflood facies interbedded with volcanic deposits. Facies relations suggest White Lake strata accumulated on coalesced, west-sloping alluvial fans that drained an active volcanic center. The overlying 0.3-km-thick Skaha Formation records increased tectonism and mass-wasting. Pervasively shattered Skaha avalanche, slide, and sheetflood deposits accumulated on alluvial fans, shed from hanging-wall and footwall sources exposed along the Okanagan Valley fault. Clast compositions of the White Lake and Skaha formations record alluvial and tectonic stripping that locally eliminated hanging-wall blocks. Mylonite clasts in upper Skaha beds imply significant Okanagan Valley fault footwall uplift during the middle Eocene and syntectonic erosion of the Shuswap metamorphic core complex. The syntectonic sedimentary record preserved within the White Lake Basin elucidates the relations and timing between core complex exhumation and extensional tectonism in this region. The White Lake and Skaha formations are the apparent age equivalent of the Klondike Mountain Formation of northern Washington (USA.). White Lake Basin strata, however, are more complexly interstratified, post-depositionally disrupted, and contain a more complete record of core complex unroofing. Variations in the spatial distributions and textural and compositional character of middle Eocene strata in this area underscore the need to exercise care when developing regional-scale sedimentary–tectonic–volcanic models.

Ambae Island is the largest of Vanuatu's active volcanoes. It is also one of the nation's potentially most dangerous, with 60 million m 3 of lake-water perched at over 1340 m in the summit caldera and over the ac- tive vent. In 1995, small phreatic explosions, earthquake swarms and heightened gas release led to calls for evacuation preparation and community volcanic hazard awareness programs for the ~9500 inhabitants. Differences in perspective or world-view between the island dwellers adhering to traditional beliefs (Kastom) and external sci- entists and emergency managers led to a climate of distrust following this crisis. In an attempt to address these issues, rebuild dialogue and respect between communities, out- side scientists and administrators, and move forward in volcanic hazard education and planning for Ambae, we adapted and applied Participatory Rural Appraisal (PRA) approaches. Initial gender-segregated PRA exercises from two representative communities provided a mechanism for cataloguing local traditional viewpoints and hazard per- ceptions. Ultimately, by combining elements of these viewpoints and perceptions with science-based manage- ment structures, we derived volcanic hazard management guidelines, supported by an alert system and map that were more readily accepted by the test communities than the earlier "top-down" plans imposed by outside govern- mental and scientific agencies. The strength of PRA ap- proaches is that they permit scientists to understand important local perspective issues, including visualisations of volcanic hazards, weaknesses in internal and external communication systems, and gender and hierarchy con- flicts, all of which can hinder community emergency management. The approach we describe has much to offer both developing and industrialised communities that wish to improve their awareness programs and mitigative planning. This approach should also enhance communi- cation and understanding between volcanologists and the communities they serve.

Sedimentary deposits from the Smith Canyon dune field, south-central Columbia Basin, Washington, U.S.A. document climatically-influenced Late Pleistocene and Holocene aeolian and fluvial deposition in a region impacted by glacial outburst floods and tephra falls. The depositional history is summarized by five environmentally distinctive and climatically sensitive sedimentary units (temporal limits estimated): Unit 1 ( c. 15·5–8 ka), pedogenically altered glacial outburst flood and minor aeolian silt and clay; Unit 2 ( c. 8–6·9 ka), fluvial and minor aeolian sand; Unit 3 ( c. 6·9–6·8 ka), flood-induced fluvial sand with gravel-sized tephra clasts; Unit 4 ( c. 6·8–3·9 ka), aeolian dune sand; Unit 5 ( c. 3·9 ka to present), pedogenically altered, stabilized dune sand. Estimated age ranges are based on stratigraphic position, tephrochronology, and correlation with temporally constrained strata from elsewhere in the region.

A facies-based approach was used to delineate both geochemical and physical aquifer property heterogeneity. Specifically, the parameters considered were the sorption coefficient (Kd) for a model organic contaminant and hydraulic conductivity (K) inferred from the particle size distribution. Subfacies-sized samples were analyzed for both tetrachloroethene Kd and K in a vertical core of the Borden aquifer. Both parameters were correlated with the six sedimentary facies identified within the vertical core. As a consequence of their relations to sedimentary facies, significant positive correlations between ln K and ln Kd which were different from the core-scale correlation and different from each other were identified for some facies. Fades-specific correlations generally resulted in improved statistics (i.e., higher correlation coefficients and reduced confidence intervals) compared to the core-scale correlation. The results suggest that a facies-based approach can be useful in characterizing the heterogeneity of the transport properties of sedimentary aquifers.

The Toroda Creek half graben is one of several north-northeast–trending Eocene extensional basins associated in time and space with the Okanogan and Kettle metamorphic core complexes in the southern Omineca crystalline belt of Washington and British Columbia. Sedimentary rocks of the middle Eocene Klondike Mountain Formation are the youngest stratified, nonvolcanic rocks in the Toroda Creek half graben. These sedimentary rocks preserve details of the character of Toroda Creek half-graben basin development in a humid temperate setting, help constrain the timing of brittle faulting in the basin, and provide insight into approximate rates of Okanogan core-complex uplift. Facies distributions and provenance determinations indicate that the Klondike Mountain Formation accumulated in a localized basin. There is no evidence that the Klondike Mountain Formation strata in the Toroda Creek half graben were once part of a more widespread deposit that later was segmented by faulting into its present configuration. Klondike Mountain sedimentary strata consist of sedimentary, gravity-dominated rock-avalanche, slide, and debris-flow deposits that accumulated on alluvial fans that delivered their sediments into either a single elongate lake or a series of possibly interconnected lakes. Provenance determinations and facies distribution patterns suggest that Klondike Mountain detritus primarily was derived from steep, unstable highlands exposed in the footwall of the Bodie Mountain fault on the east side of the basin. Sediments at the southern end of the basin were shed from an upland created by a west-northwest–trending transfer fault (Granite Creek fault). Rates of footwall uplift (and/or basin subsidence) estimated from unroofing of plutonic and presumed mylonitic rocks suggest rapid and significant basin margin uplift.

A regional climate model (RCM) developed for the Hanford Site, Washington illustrates a potentially useful method for assessing eolian responses to regional climate change. The RCM is based on long-term relations between fundamental climatic variables of precipitation, temperature, and wind speed. Modelled data are integrated into eolian-climatic scenarios through maps of eolian susceptibility, plots of sand dune mobility, and calculated trends of unvegetated dune sand volumes. Results demonstrate the sensitivity of eolian-climatic interactions to small changes in precipitation. Analyses suggest that continuation of the 1977–1987 trend toward a cooler (−0.16°C) and wetter (+1.8 cm yr −1 ) climate over the next 10–15 years will result in a decrease of ∼18% in the volume of unvegetated dune sand. Further temperature reductions totaling 0.7°C would promote precipitation increases of 30% leading to an additional reduction of 98% in the volume of unvegetated dune sand. Modelling scenarios for a possible global warming of +4°C indicate that annual precipitation at Hanford would be negligible and vegetation would be eliminated from dune surfaces. Sand dune mobility would increase by over 400%.

Aeolian-climatic thresholds are quantified using time sequence analysis of 1948-87 aeolian and climatic data from the Hanford Site, south-central Washington. Calculations indicate that 30 unvegetated sand dunes will maintain their total 1987 volume if they are exposed to a climate having an average annual precipitation, wind speed, and temperature of approximately 15·5 cm, 3·5 ms −1 , and 11·8°C, respectively. Calculations also show that if average 1948-87 climate conditions continue for the next approximately 10–15 years, the volume of unvegetated dune sand in the dunes studied will decrease by approximately 18%. Aeolian-climatic projections are based on the assumptions that there will be no major changes in human, animal, or botanical impact on the surface and no major variations from historical seasonal climatic patterns.

Optical dating of late Quaternary quartz dune sands from the Clear Creek portion of Ferris dune field, Wyoming, demonstrates the considerable potential of the technique as a chronostratigraphic tool. A sequence of radiocarbon-dated Holocene interdune strata permit optical dating of the intercalated dune sand to be tested; the concordance is good. The optical dates for the aeolian deposits not datable by radiocarbon suggest that aeolian sedimentation at Clear Creek peaked during two relatively short phases at ca. 8500 and 4000 yr B.P. The dates indicate that aeolian accumulation maxima (at least in the Clear Creek area) may not be synchronous with previously defined phases of marked aridity.

Quartzose and lesser argillaceous strata of the approximately 1300 m thick Upper Proterozoic (?) to Lower Cambrian Addy Quartzite of northeastern Washington record shelf, coastal, and continental sedimentation on an actively subsiding, relatively young passive margin. The lower 400 to 500 m of the Addy Quartzite was deposited immediately following the initiation of subsidence in a wave-dominated coastal and eventually storm-dominated shelf environment. This sequence records relative sea level rise that culminated in high-stand conditions. These sediments grade upwards into approximately 150 m of fluvial strata that record progradation of terrestrial environments during a period of relative sea level fall and a regional low-stand. The upper 700 m of the Addy Quartzite fines upwards from nearshore- to shallow-marine-dominated sediments into shelf-dominated deposits. This sequence marks the reestablishment of net sea level rise. The overall fining-upwards trend displayed by the Addy Quartzite indicates that regional subsidence of the newly formed passive margin was one of the most important factors controlling Addy sedimentation. However, variation seen in this trend throughout the Addy Quartzite indicates that rates of sea level rise associated with subsidence fluctuated and occasionally even reversed. Causes for the variation are inferred to be related to variations in subsidence rates and sediment supply. Textural and compositional data suggest Addy detritus was derived from relatively proximal recycled sedimentary source terranes and more distal continental crystalline terranes.

Aquifer heterogeneities defined by mapping and correlating lithofacies derived from existing geologic and borehole geophysical data at the U.S. Department of Energy's (DOE) Hanford Site (south–central Washington) were compared to tritium migration trends within the unconfined aquifer. Lithofacies percentage maps proved useful in defining large–scale (on the order of miles) tritium migration pathways at Hanford but were not sufficiently detailed to serve as unambiguous predictors of these pathways. Results suggest that: (1) incorporation of geologic parameters more closely related to hydraulic properties (e.g., quantified grain size and sorting, degree of cementation, packing arrangement, sedimentary structures, and grain shape), and (2) conscientious integration of all hydrogeologic data at the Hanford Site (and elsewhere) will allow definition of three-dimensional aquifer elements termed “hydrofacies” and enhance reliable prediction of contaminant migration pathways. Strict reliance on standard fluvial models in the evaluation of lithofacies at Hanford is not appropriate for predicting plume migration because of the complex depositional and erosional history of the sediments comprising the unconfined aquifer. Use of “hydrofacies” ultimately may serve as the appropriate conceptual framework for predicting plume migration.

An approximately 25-m thick sequence of dune and interdune strata exposed at Clear Creek in south-central Wyoming records arid to semi-arid paleoclimatic fluctuations spanning approximately the last 7500 years. The Clear Creek strata are subdivided into six informal chronostratigraphic intervals that bracket climatically-distinctive episodes of dune and interdune sedimentation and are constrained chronologically by 14C dates. The six intervals are: 7545–7035 (I), 7035–6460 (II), 6460–5940 (III), 5940–4540 (IV), 4540–2155 (V), and 2155 years B.P. to Present (VI). At least four episodes of enhanced eolian activity that reflect increased aridity are recorded in the Clear Creek strata. The most arid climatic episodes occurred during the years 7545–7035 B.P. chronostratigraphic interval I; lesser peaks of aridity occurred during 5940–4540 B.P interval IV. The climate during 7035–6460 B.P. interval II and 4540–2155 B.P. interval V was transitional between arid and semi-arid conditions. Climatic conditions during the years 6460–5940 B.P. interval III and 2155 B.P. to Present interval VI have been relatively moist and semi-arid.

[1] We determined the descriptive statistical and spatial geostatistical properties of the perchloroethene ln Kd and the ln k of a 1.5 m thick by 10 m horizontal transect of the Borden aquifer near the location of the Stanford-Waterloo (SW) tracer experiment. The ln Kd distribution is not normal and is right skewed because of a few high values that occur localized in two regions of the transect. In contrast, the ln k data can be characterized by a normal distribution. A linear regression of ln Kd on ln k yields a statistically significant positive correlation, also shown at small lags in the cross correlogram. No significant vertical or horizontal trend in the ln Kd data was detected. The semivariogram ranges of ln k and ln Kd differ from one another in the vertical direction (0.33 ± 0.06 m and 0.20 ± 0.04 m, respectively) and are much less than the horizontal ranges (a few meters). Despite significant effort the horizontal range of ln Kd remains poorly characterized because of limitations of the sample locations. Many of the characteristics described above do not match those assumed in prior theoretical studies that examined the importance of various aquifer characteristics on SW tracer transport. We suggest that there is knowledge to be gained by revisiting the conclusions of these prior studies in light of the new information presented here.

A highly crevassed region near a grounded ice rise on the Ross Ice Shelf, Antarctica was investigated and found to contain poorly sorted sediments. Preliminary analysis of a 27 g sample of sediments was undertaken using megascopic, microscopic, and X-ray diffraction methods. Igneous and meta-morphic rock fragments, their constituent minerals, and micro-fossils were noted in the sample. Insufficient data have been collected at this time to denote a particular source area for the sediments.

The integration of atmospheric soundings from a fully instrumented aircraft with detailed sedimentary and geomorphic analyses of eolian features in the Ferris dune field of south-central Wyoming lends insight into the manner in which topography interacts with airflow to modify eolian activity. Topographically modified airflow results in zones of airflow deceleration, acceleration, and enhanced atmospheric turbulence, all of which influence the surface morphology and sedimentology. Extreme lateral confluence of prevailing airflow produces accelerated, unidirectional winds. These winds correlate with unusually continuous and elongate parabolic dunes that extend into a mountain gap (Windy Gap). Persistently heightened winds produced at the entrance to Windy Gap have resulted in a concentration of active sand dunes that lack slipfaces. Common development of a strongly amplified atmospheric wave analogous to a hydraulic jump in the gap contributes to the formation of a variety of eolian features that mantle the surface of Windy Gap and the Ferris dune field tail. Heightened, unidirectional winds in this zone promote grain-size segregation, the formation of elongated and aligned sand drifts, climbing and falling dunes, elongate scour streaks, and parabolic dunes that have low-angle (< 20/sup 0/) cross-stratification. Deflation of bedrock and loose sediment has been enhanced in the zonemore » of maximum turbulence beneath the hydraulic jump.« less