In April 2005, the U.S. Geological Survey (USGS) conducted field studies on the Wind River Indian Reservation, Wyoming, to inventory and evaluate sand and gravel deposits underlying river terraces on tribal lands along the Wind River. This report contains the results for 12 sites of sand and gravel deposits evaluated for their potential use as aggregate in Portland cement concrete, asphalt, and base course. The report provides the results of: * The USGS geologic studies and engineering tests. * A conclusion and recommendation for the best use of sand and gravel materials. * Calculations of available sand and gravel materials. * A scenic quality landscape inventory and evaluation.

In this report we describe a series of stepped Quaternary terraces on some piedmont tributaries of the Santa Cruz River valley in southeastern Arizona. These terraces began to form in early Pleistocene time, after major basin-and-range faulting ceased, with lateral planation of basin fill and deposition of thin fans of alluvium. At the end of this cycle of erosion and deposition, tributaries of the Santa Cruz River began the process of dissection and terrace formation that continues to the present. Vertical cutting alternated with periods of equilibrium, during which streams cut laterally and left thin deposits of channel fill. The distribution of terraces was mapped and compiled with adjacent mapping to produce a regional picture of piedmont stream history in the middle part of the Santa Cruz River valley. For selected tributaries, the thickness of terrace fill was measured, particle size and lithology of gravel were determined, and sedimentary features were photographed and described. Mapping of terrace stratigraphy revealed that on two tributaries, Madera Canyon Wash and Montosa Canyon Wash, stream piracy has played an important role in piedmont landscape development. On two other tributaries, Cottonwood Canyon Wash and Josephine Canyon Wash, rapid downcutting preempted piracy. Two types of terraces are recognized: erosional and depositional. Gravel in thin erosional terraces has Trask sorting coefficients and sedimentary structures typical of streamflood deposits, replete with bar-and-swale surface topography on young terraces. Erosional-terrace fill represents the channel fill of the stream that cuts the terrace; the thickness of the fill indicates the depth of channel scour. In contrast to erosional terraces, depositional terraces show evidence of repeated deposition and net aggradation, as indicated by their thickness (as much as 20+ m) and weakly bedded structure. Depositional terraces are common below mountain-front canyon mouths where streams drop their load in response to abrupt flattening of gradients and expansion of channel banks, and they extend down the piedmont along Josephine Canyon Wash. Gravel in depositional terraces also has sorting coefficients typical of streamflood deposits. Sedimentary features in both types of terraces are consistent with deposition by flash floods in ephemeral streams, suggesting the climate was arid. Bedding and clast armor are weakly developed, clast clusters and imbrication are common, and crossbedding is generally absent. Debris-flow deposits, even near the mountain front, are surprisingly rare. On the tectonically stable piedmont of southeastern Arizona, stream piracy and climate change are the most likely agents of terrace formation. Both piracy and climate change can cause rapid changes in discharge and sediment supply, which initiate cycles of incision, lateral cutting, and aggradation. Increased stream discharge initiates downcutting, but increased sediment supply interrupts downcutting and causes streams to cut laterally and aggrade. At times, on Madera Canyon Wash and Montosa Canyon Wash, stream piracy affected stream discharge and sediment supply, but on Cottonwood Canyon Wash and Josephine Canyon Wash, only climate change could have initiated terrace cutting. Terraces probably formed during extended arid intervals when sparse vegetation and flashy stream discharge combined to increase sediment supply. In most cases, sediment supply was sufficient to promote lateral cutting but not long-term aggradation. Thus, most streams formed erosional terraces. The middle Pleistocene Josephine Canyon Wash formed a depositional terrace because it had a source of abundant unconsolidated sediment.

Contingency table analysis of pebble lithology and roundness is an effective way to identify the source terrane of a drainage basin and to distinguish changes in basin size, piracy, tectonism, and other events. First, the analysis to terrace gravel deposited by the Huangshui River, northeastern Tibet Plateau, China, shows statistically contrasting pebble populations for the oldest terrace (T7, Dadongling, 1.2Ma) and the youngest terraces (T0–T3, ≤0.15Ma). Two fluvial processes are considered to explain the contrast in correlation between lithology and roundness in T7 gravel versus T0–T3 gravel: 1) reworking of T7 gravel into T0–T3 gravel and 2) growth in the size of the river basin between T7 and T0–T3 times. We favor growth in basin size as the dominant process, from comparison of pebble counts and contingency tables. Second, comparison of results from Huangshui River of China to three piedmont streams of the Rocky Mountains, USA highlights major differences in source terrane and history. Like Rocky Mountain piedmont gravel from Colorado examples, the Huangshui gravels show a preference (observed versus expected frequency) for rounded granite. But unlike Rocky Mountain gravel, Huangshui gravel shows a preference for angular quartzite and for rounded sandstone. In conclusion, contrasting behavior of lithologies during transport, not always apparent in raw pebble counts, is readily analyzed using contingency tables to identify the provenance of individual lithologies, including recycled clasts. Results of the analysis may help unravel river history, including changes in basin size and lithology.

Clast populations in piedmont fluvial systems are products of complex histories that complicate provenance interpretation. Although pebble counts of lithology are widely used, the information provided by a pebble count has been filtered by a potentially large number of processes and circumstances. Counts of pebble lithology and roundness together offer more power than lithology alone for the interpretation of provenance.In this study we analyze pebble counts of lithology and roundness in two contrasting fluvial systems of Pleistocene age to see how provenance varies with drainage size. The two systems are 1) a group of small high-gradient incised streams that formed alluvial fans and terraces and 2) a piedmont river that formed terraces in response to climate-driven cycles of aggradation and incision. We first analyze the data from these systems within their geographic and geologic context. After this is done, we employ contingency table analysis to complete the interpretation of pebble provenance.Small tributary streams that drain rugged mountains on both sides of the Santa Cruz River, southeast Arizona, deposited gravel in fan and terrace deposits of Pleistocene age. Volcanic, plutonic and, to a lesser extent, sedimentary rocks are the predominant pebble lithologies. Large contrasts in gravel lithology are evident among adjacent fans. Subangular to subrounded pebbles predominate. Contingency table analysis shows that hard volcanic rocks tend to remain angular and, even though transport distances have been short, soft tuff and sedimentary rocks tend to become rounded.The Wind River, a major piedmont stream in Wyoming, drains rugged mountains surrounding the northwest part of the Wind River basin. Under the influence of climate change and glaciation during the Pleistocene, the river deposited an extensive series of terrace gravels. In contrast to Santa Cruz tributary gravel, most of the Wind River gravel is relatively homogenous in lithology and is rounded to well-rounded. Detailed analysis reveals a multitude of sources in the headwaters and the basin itself, but lithologies from these sources are combined downstream. Well-rounded volcanic and recycled quartzite clasts were derived from the headwaters. Precambrian igneous and metamorphic clasts were brought down tributary valleys to the Wind River by glaciers, and sandstone was added where the river enters the Wind River structural basin. Published by Elsevier B.V.

A unit of the Mesoproterozoic Apple Creek Formation of the Lemhi Range previously was correlated with part of the lower subunit of the Mesoproterozoic Yellowjacket Formation in the Salmon River Mountains. Strata currently assigned to the middle subunit of the Yellowjacket Formation lie conformably above the Apple Creek unit in the Salmon River Mountains, and are here renamed the banded siltite unit and reassigned to the Apple Creek Formation. Almost all of the banded siltite unit is preserved within the Salmon River Mountains, where it grades upward into clastic rocks that currently are assigned to the upper subunit of the Yellowjacket Formation and that here are reassigned to the Gunsight Formation. The banded siltite unit of the Apple Creek Formation is composed of a turbidite sequence, as recognized by previous workers. Uppermost strata of the unit were reworked by currents, possibly storm generated, and adjusted to a high water content by developing abundant soft-sediment deformation features. Basal strata of the overlying Gunsight Formation in the Salmon River Mountains display abundant hummocky crossbeds, storm-generated features deposited below fair-weather wave base, that are conformable above the storm-reworked deposits. The hummocky crossbedded strata grade upward into marine shoreface strata deposited above fair-weather wave base, which in turn are succeeded by fluvial strata. Hummocky and shoreface strata are absent from the Gunsight Formation in the Lemhi Range. The major thickness of the Gunsight Formation in both the Salmon River Mountains and the Lemhi Range is composed of fluvial rocks, transitional in the upper part into marine rocks of the Swauger Formation. The fluvial strata are mainly characterized by stacked sheets of metasandstone and coarse siltite; they are interpreted as deposits of braided rivers. The Poison Creek thrust fault of the Lemhi Range extends northwestward through the study area in the east-central part of the Salmon River Mountains. The Apple Creek and Gunsight Formations on the southwest side of the thrust fault were transported to the northeast as part of the Poison Creek thrust sheet. A segment of the thrust fault within the Gunsight Formation in the Salmon River Mountains subsequently underwent normal displacement. Along this segment, lower Gunsight strata on the southwest were juxtaposed against upper Gunsight and Swauger strata on the northeast.

Introduction This publication contains four descriptive models and four grade-tonnage models for sediment hosted copper deposits. Descriptive models are useful in exploration planning and resource assessment because they enable the user to identify deposits in the field and to identify areas on geologic and geophysical maps where deposits could occur. Grade and tonnage models are used in resource assessment to predict the likelihood of different combinations of grades and tonnages that could occur in undiscovered deposits in a specific area. They are also useful in exploration in deciding what deposit types meet the economic objectives of the exploration company. The models in this report supersede the sediment-hosted copper models in USGS Bulletin 1693 (Cox, 1986, and Mosier and others, 1986) and are subdivided into a general type and three subtypes. The general model is useful in classifying deposits whose features are obscured by metamorphism or are otherwise poorly described, and for assessing regions in which the geologic environments are poorly understood. The three subtypes are based on differences in deposit form and environments of deposition. These differences are described under subtypes in the general model. Deposit models are based on the descriptions of geologic environments and physical characteristics, and on metal grades and tonnages of many individual deposits. Data used in this study are presented in a database representing 785 deposits in nine continents. This database was derived partly from data published by Kirkham and others (1994) and from new information in recent publications. To facilitate the construction of grade and tonnage models, the information, presented by Kirkham in disaggregated form, was brought together to provide a single grade and a single tonnage for each deposit. Throughout the report individual deposits are defined as being more than 2,000 meters from the nearest adjacent deposit. The deposit models are presented here as a PDF file. The database can be most conveniently read in FileMaker Pro. For those who do not have the FileMaker application, Microsoft-Excel, tab-delimited-ASCII and comma-separated-value files are included. The reader may be interested in a similar publication on porphyry copper deposits (Singer and others, 2005) also available online. The Google Earth image is not intended to be viewed at the highest possible magnification because the resolution of the database is plus or minus two kilometers. At extreme zoom settings, the deposit locations may not coincide with the Google-Earth images of the mine workings.

The principal purpose of this report is to provide a reference archive for results of a statistical analysis of geochemical data for metasedimentary rocks of Mesoproterozoic age of the Salmon River Mountains and Lemhi Range, central Idaho. Descriptions of geochemical data sets, statistical methods, rationale for interpretations, and references to the literature are provided. Three methods of analysis are used: R-mode factor analysis of major oxide and trace element data for identifying petrochemical processes, analysis of variance for effects of rock type and stratigraphic position on chemical composition, and major-oxide ratio plots for comparison with the chemical composition of common clastic sedimentary rocks.

Construction and maintenance of the infrastructure is dependent on such raw materials as aggregate (crushed stone, sand, and gravel). Despite this dependence, urban expansion often works to the detriment of the production of those essential raw materials. The failure to plan for the protection and extraction of aggregate resources often results in increased consumer cost, environmental damage, and an adversarial relation between the aggregate industry and the community. As an area grows, the demand for aggregate resources increases, and industries that produce these materials are established. Aggregate is a low-cost commodity, and to keep hauling costs at a minimum, the operations are located as close to the market as possible. As metropolitan areas grow, they encroach upon established aggregate operations. New residents in the vicinity of pits and quarries object to the noise, dust, and truck traffic associated with the aggregate operation. Pressure is applied to the local government to limit operation hours and truck traffic. In addition to encroaching on established aggregate operations, urban growth commonly covers unmined aggregate resources. Frequently urban growth occurs without any consideration of the resource or an analysis of the impact of its loss. The old idea that aggregate resources can be found anywhere is false. New aggregate operations may have to be located long distances from the markets. The additional expense of the longer transport of resources must be passed on to consumers in the community. In many instances, the new deposit is of inferior quality compared with the original source, yet it is used to avoid the expense of importing high-quality material from a more-distant source. Some governmental, including city, provincial or state, and national, agencies, have enacted regulations to help maintain access to prime aggregate resources. Although regulations have met with variable success, some policy or regulation to protect aggregate resources is worth consideration. A basic requirement of any aggregate resource policy or regulation is the knowledge of the geographic distribution, volumes, and quality of aggregate resources. This knowledge commonly is obtained through geologic mapping and characterization of aggregate resources. Geographic Information Systems (GIS) and Decision Support Systems (DSS) provide excellent tools to help present and evaluate the information in a manner that is understandable by public decisionmakers.

This investigation was conducted to provide information on the aggregate potential of alluvial fan sediments in the Santa Cruz River valley.Pebble lithology, roundness, and particle size were determined in the field, and structures and textures of alluvial fan sediments were photographed and described.Additional measurements of particle size on digital photographs were made on a computer screen.Digital elevation models were acquired and compiled for viewing the areal extent of selected fans.Alluvial fan gravel in the Santa Cruz River valley reflects the lithology of its source.Gravel derived from granitic and gneissic terrane of the Tortolita, Santa Catalina, and Rincon Mountains weathers to grus and is generally inferior for use as aggregate.Gravel derived from the Tucson, Sierrita, and Tumacacori Mountains is composed mostly of angular particles of volcanic rock, much of it felsic in composition.This angular volcanic gravel should be suitable for use in asphalt but may require treatment for alkalisilica reaction prior to use in concrete.Gravel derived from the Santa Rita Mountains is of mixed plutonic (mostly granitic rocks), volcanic (mostly felsic rocks), and sedimentary (sandstone and carbonate rock) composition.The sedimentary component tends to make gravel derived from the Santa Rita Mountains slightly more rounded than other fan gravel.The coarsest (pebble, cobble, and boulder) gravel is found near the heads (proximal part) of alluvial fans.At the foot (distal part) of alluvial fans, most gravel is pebble-sized and interbedded with sand and silt.Some of the coarsest gravel was observed near the head of the Madera Canyon, Montosa Canyon, and Esperanza Wash fans.The large Cienega Creek fan, located immediately south and southeast of Tucson, consists entirely of distal-fan pebble gravel, sand, and silt.

Pebble count data from Quaternary gravel deposits north of Denver, Colo., were analyzed by multivariate statistical methods to identify lithologic factors that might affect aggregate quality. The pebble count data used in this analysis were taken from the map by Colton and Fitch (1974) and are supplemented by data reported by the Front Range Infrastructure Resources Project. This report provides data tables and results of the statistical analysis. The multivariate statistical analysis used here consists of log-contrast principal components analysis (method of Reyment and Savazzi, 1999) followed by rotation of principal components and factor interpretation. Three lithologic factors that might affect aggregate quality were identified: 1) granite and gneiss versus pegmatite, 2) quartz + quartzite versus total volcanic rocks, and 3) total sedimentary rocks (mainly sandstone) versus granite. Factor 1 (grain size of igneous and metamorphic rocks) may represent destruction during weathering and transport or varying proportions of rocks in source areas. Factor 2 (resistant source rocks) represents the dispersion shadow of metaquartzite detritus, perhaps enhanced by resistance of quartz and quartzite during weathering and transport. Factor 3 (proximity to sandstone source) represents dilution of gravel by soft sedimentary rocks (mainly sandstone), which are exposed mainly in hogbacks near the mountain front. Factor 1 probably does not affect aggregate quality. Factor 2 would be expected to enhance aggregate quality as measured by the Los Angeles degradation test. Factor 3 may diminish aggregate quality.

This trip will cross the northern Sangre de Cristo Range, from Westcliffe to Crestone, Colorado, by way of the Hermit Pass Road and the Rito Alto pack trail (Fig. 1 below; road and trail shown on Fig. 2). The traverse is designed to give the geologist a sample of the structure and stratigraphy of this part of the range. Emphasis will be on the relationship between the horst of the Sangre de Cristo Range and adjacent down-dropped valleys, on the Laramide thrusted structure of the range, and on the stratigraphy and depositional environments of Pennsylvanian and Permian sedimentary rocks in the range.The northern Sangre de Cristo Range is composed mostly of Early and Middle Proterozoic crystalline rocks and Paleozoic clastic sedimentary rocks (see geologic map, Fig. 2). Proterozoic rocks, mostly gneiss and quartz monzonite, are overlain on the west side of the range by about 100 m of early Paleozoic quartzite, dolomite, limestone, and shale. Early Paleozoic rocks are in turn unconformably overlain by Pennsylvanian and Permian clastic rocks. Southeast of the range, in Huerfano Park, Paleozoic rocks are overlain by Jurassic and Cretaceous rocks of the Raton basin.

This report describes the mineral and chemical composition of immature, arkosic sandstones of the Pennsylvanian Minturn and Pennsylvanian and Permian Sangre de Cristo Formations, which were derived from the Ancestral Rocky Mountains. Located in the Sangre de Cristo Range of southern Colorado, the Minturn and Sangre de Cristo Formations contain some of the most immature, sodic arkoses shed from the Ancestral Rocky Mountains. The Minturn Formation was deposited as fan deltas in marine and alluvial environments; the Sangre de Cristo Formation was deposited as alluvial fans. Arkoses of the Minturn and Sangre de Cristo Formations are matrix-rich and thus may be properly considered arkosic wackes in the terminology of Gilbert (Williams and others, 1954). In general, potassium feldspar and plagioclase are subequal in abundance. Arkose of the Sangre de Cristo Formation is consistently plagioclase-rich; arkose from the Minturn Formation is more variable. Quartz and feldspar grains are accompanied by a few percent rock fragments, consisting mostly of intermediate to granitic plutonic rocks, gneiss, and schist. All of the rock fragments seen in sandstone are present in interbedded conglomerate, consistent with derivation from a Precambrian terrane of gneiss and plutonic rocks much like that exposed in the present Sangre de Cristo Range. Comparison of mineral and major oxide abundances reveals a strong association of detrital quartz with SiO2, all other detrital minerals (totaled) with Al2O3, potassium feldspar plus mica with K2O, and plagioclase with Na2O. Thus, major oxide content is a good predictor of detrital mineralogy, although contributions from matrix and cement make these relationships less than perfect. Detrital minerals and major oxides tend to form inverse relationships that reflect mixtures of varying quantities of minerals; when one mineral is abundant, the abundance of others declines by dilution. In arkose of the Minturn and Sangre de Cristo Formations, the abundance of quartz (and SiO2) is enhanced by weathering and transport, which destroys feldspar and rock fragments. Weathering also preferentially destroys plagioclase (and removes Na2O) over potassium feldspar. Thus, as fresh sodic arkose detritus is weathered and transported in the fluvial environment, it becomes potassic and quartz-rich. Stratigraphic profiles of mineral and major oxide abundance reveal that weathering and transport, including reworking by marine currents, was most effective in reducing plagioclase and enhancing quartz content of arkosic sediment in the Minturn Formation near Marble Mountain. In general, the quartz-poor, sodic arkoses of the Sangre de Cristo Formation indicate little weathering in the source area or during transport. Iron-titanium oxides and other heavy minerals, notably zircon and sphene, tend to be most abundant in the Sangre de Cristo Formation. Although concentrated locally as fluvial placers, the overall abundance of heavy minerals probably reflects lack of weathering and proximity to source. The degree of weathering and destruction of unstable grains (feldspar and rock fragments) in the Minturn and Sangre de Cristo Formations of the Sangre de Cristo Range was dependent on rates of uplift and erosion as much as climate (wet versus dry). Reworking by marine currents further reduced the proportion of unstable grains during Minturn time. Sodic (plagioclase-rich), quartz-poor arkose in the coarse, conglomeratic Sangre de Cristo Formation is the product of rapid uplift and erosion.

The U.S. Geological Survey initiated the Front Range Infrastructure Resources Project in October 1995, to collect, compile, and analyze new and existing data on aggregate, water, and energy resources along the Colorado Front Range. Data collection and methods development primarily were restricted to a demonstration area consisting of the Denver metropolitan area and the rapidly growing areas to the north. Project results to date on aggregate resources include digital aggregate resource maps; developing aggregate deposit resource models, formulation of field tools, geophysical and remote sensing techniques, computer processing and display of data including geographic information systems and decision support systems; and investigating human related aspects such as sterilization, supply and demand, and mined-land reclamation. The aggregate studies of this project are being conducted in cooperation with the Colorado Geological Survey, and with industry organizations including the National Stone Association and the Colorado Rock Products Association.

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. This report can be downloaded via ‘anonymous ftp’ from a USGS system named greenwood.cr.usgs.gov (136.177.21.122). The file is located in a directory named /pub/open-filereports/ofr-97-0451.

Crushed stone and sand and gravel are the main types of natural aggregate used in the United States. Aggregate is used in nearly all residential, commercial, and industrial building construction, and in most public works projects including roads and highways, bridges, railroad and light rail beds, airports, water and sewer systems, and tunnels. Much of the infrastructure built during the 1950s and 1960s has deteriorated to a point that requires extensive repair or replacement. All this construction requires enormous amounts of aggregate. In Colorado, for example, nearly 45 million tons of aggregate, or about 12 tons per person, were produced during 1994.