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Thermal springs in the United States

The earliest extensive studies of thermal springs in the United States were made by physicians. In 1831 Dr. John Bell issued a book entitled "Baths and Mineral Waters" in which he listed 21 spring localities. In the edition of his work published in 1855 the number was increased to 181. The earliest report on a geologic study of thermal springs was that of W. B, Rogers in 1840 on the thermal springs of Virginia. In 1875 G. K. Gilbert published a map and table showing thermal springs in the United States and pointed out that they are present chiefly in the mountainous areas of folded and faulted rocks. Early geologic study of them was principally inspired by the information which they afford at a few places on the deposition of minerals. The relation of hot springs to volcanic action has been studied in the Yellowstone National Park and near Lassen Peak in California. Studies in recent years have been concerned with the source of the water as well as of its heat. All the notable thermal springs in the eastern United States are in the Appalachian Highlands, principally in the region of folded rocks. The Atlantic Coastal Plain contains no appreciably warm springs. In Florida there are large springs whose water rises from a depth of a few hundred feet and is about 5° above the mean annual temperature, but they are not usually classed as thermal. The only warm springs in the great Interior Plains region are at and near Hot Springs, S. Dak., in the vicinity of the Black Hills uplift of crystalline rocks. In the Interior Highlands thermal springs occur only in the Ozark region, the largest group being at Hot Springs, Ark. The Rocky Mountain System includes the Yellowstone National Park, with its world-famous hot springs and geysers (see pis. 7,12), and there are many other hot springs within this great mountainous region. In the Intermontane areas of great lava plains and faulted lava mountains in Utah, Nevada, southern Idaho, and eastern Oregon there are many hot springs, closely associated with the larger faults. In the Pacific Mountain System, including the Cascade Range and Sierra Nevada, there are many warm and hot springs, some of which issue in areas of granite, and others in areas of lava. In the Coast Ranges of California many thermal springs issue from different geologic formations. Of the total of more than 1,000 thermal-spring localities listed in this paper more than half are situated in the three States of Idaho, California, and Nevada, each of which contains more than 150 thermal-spring localities. Wyoming, including the Yellowstone National Park, contains more than 100 hot-spring localities. Oregon, Utah, Colorado, Montana, and New Mexico contain several dozen thermal springs each, of which the principal ones are developed as resorts. The other thermal springs are scattered through 12 States, of which Massachusetts, New York, Pennsylvania, and North Carolina contain one spring or group each. More than half of the total number are developed as resorts or used for irrigation or water supply, but many have remained undeveloped because they are not easily accessible.

Water Supply Paper↗

Understanding contaminants associated with mineral deposits

Interdisciplinary studies by the U.S. Geological Survey (USGS) have resulted in substantial progress in understanding the processes that control the release of metals and acidic water from inactive mines and mineralized areas, the transport of metals and acidic water to streams, and the fate and effect of metals and acidity on downstream ecosystems. The potential environmental effects associated with abandoned and inactive mines, resulting from the complex interaction of a variety of chemical and physical processes, is an area of study that is important to the USGS Mineral Resources Program. Understanding the processes contributing to the environmental effects of abandoned and inactive mines is also of interest to a wide range of stakeholders, including both those responsible for managing lands with historically mined areas and those responsible for anticipating environmental consequences of future mining operations. The recently completed (2007) USGS project entitled 'Process Studies of Contaminants Associated with Mineral Deposits' focused on abandoned and inactive mines and mineralized areas in the Rocky Mountains of Montana, Colorado, New Mexico, Utah, and Arizona, where there are thousands of abandoned mines. Results from these studies provide new information that advances our understanding of the physical and biogeochemical processes causing the mobilization, transport, reaction, and fate of potentially toxic elements (including aluminum, arsenic, cadmium, copper, iron, lead, and zinc) in mineralized near-surface systems and their effects on aquatic and riparian habitat. These interdisciplinary studies provide the basis for scientific decisionmaking and remedial action by local, State, and Federal agencies charged with minimizing the effects of potentially toxic elements on the environment. Current (2007) USGS research highlights the need to understand (1) the geologic sources of metals and acidity and the geochemical reactions that release them from their sources, (2) the pathways that facilitate transport from those sources, and (3) the processes that control the fate of the elements once released from the sources. Experts in the fields of economic geology, structural geology, mineralogy, geophysics, geochemistry, hydrology, ground-water modeling, microbiology, and toxicology came together for a series of studies that address these relationships on scales ranging from the microscopic to the watershed. This Circular presents results and highlights from the detailed, interdisciplinary studies that include investigations in both mining-affected areas and mineralized but unmined areas. The first section of the Circular describes laboratory and site-scale field investigations that primarily focus on mineralogic and biologic controls on the source and release of metals and acidity from mine-waste rock and hydrothermally altered areas. The second section describes a set of basin- to watershed-scale studies that not only investigate the source and release of metals and acidity but also the transport of these constituents away from the source areas. The third section is a summary of results from postremediation ecosystem monitoring. For more information on these and other project-related studies, please visit the project Web site at http://minerals.cr.usgs.gov/projects/contaminants/index.html. The Web site includes a complete bibliography and detailed descriptions of each interdisciplinary study.

Circular↗

RV Ocean Surveyor Cruise O1-02-GM; bathymetry and acoustic backscatter of selected areas of the Outer Continental Shelf, northwestern Gulf of Mexico; June 8, through June 28, 2002; Iberia, LA to Iberia, LA

Following the publication of high-resolution multibeam echosounder (MBES) images and data of the Flower Gardens area of the northwest Gulf of Mexico outer continental shelf (Gardner et al., 1998), the Flower Gardens Banks National Marine Sanctuary (FGBNMS) and the Minerals Management Service (MMS) have been interested in additional MBES data in the area. A coalition of FGBNMS, MMS, and the US Geological Survey (USGS) was formed to map additional areas of interest in the northwestern Gulf of Mexico in 2002. The areas were chosen by personnel of the FGBNMS and the choice of MBES was made by the USGS. MMS and FGBNMS funded the mapping and the USGS organized the ship and multibeam systems through a Cooperative Agreement between the USGS and the University of New Brunswick. The University of New Brunswick (UNB) contracted the RV Ocean Surveyor and the EM1000 MBES system from C&C Technologies, Inc., Lafayette, LA. C&C personnel oversaw data collection whereas UNB personnel conducted the cruise and processed all the data. USGS personnel were responsible for the overall cruise including the final data processing and digital map products.

Louisiana↗

Water-quality, bed-sediment, and discharge data for the Mississippi River-Gulf Outlet and adjacent waterways, southeastern Louisiana, August 2008 through December 2009

The Mississippi River-Gulf Outlet navigation channel (MRGO) was constructed in the early 1960s to provide a safer and shorter route between the Gulf of Mexico and the Port of New Orleans for deep-draft, ocean-going vessels and to promote the economic development of the Port of New Orleans. In 2006, the U.S. Army Corps of Engineers developed a plan to de-authorize the MRGO. The plan called for a rock barrier to be constructed across the MRGO near Bayou La Loutre. In 2008, the U.S. Geological Survey, in cooperation with the Louisiana Coastal Area Science and Technology Program began a study to document the impacts of the rock barrier on water-quality and flow before, during, and after its construction. Water-quality, bed-sediment, and discharge data were collected in the MRGO and adjacent water bodies from August 2008 through December 2009.

Louisiana↗

U. S. GEOLOGICAL SURVEY'S RESEARCH PROGRAM IN THE NEWLY PROCLAIMED EXCLUSIVE ECONOMIC ZONE.

The U. S. Geological Survey (USGS) has been developing a program which would emphasize broad-scale surveys of the continental margin and intensive studies of 'baseline corridors' in various areas of the U. S. EEZ to gather energy and mining information in this new frontier as quickly as possible. Of twelve baseline corridors identified to date along the east and west coasts and the Gulf of Mexico, the highest priority would be placed on areas off the west coast, including Juan De Fuca and Gorda Ridges and off Hawaii. Each corridor assessment will involve collection of multi-channel and high resolution geophysical data, bottom relief and sampling, and production of reports and cartographic products displaying the scientific findings of the assessments.

Conference Paper↗

Front matter: Preface, acknowledgements, table of contents

This volume is the fifth in a series of reports by the U.S. Geological Survey (USGS) on the assessment of the quantity and quality of the nation’s coal deposits that potentially could be mined during the next few decades. For eight years (1995-2003), geologic, geochemical, and resource information was collected and compiled for the five major coal-producing regions of the United States: the Appalachian Basin, Illinois Basin, Northern Rocky Mountains and Great Plains, Colorado Plateau, and the western part of the Gulf of Mexico Coastal Plain (Gulf Coast) region. The results of these other USGS coal assessments may be found at: http://energy.cr.usgs.gov/coal/coal_assessments/ index.html and a summary of the results from all assessment areas can be found in Ruppert et al. (2002) and Dennen (2009). This volume contains the assessment results for the Gulf Coast region. The contents of this volume were compiled mainly during the eight-year period mentioned above. However, every effort has been made to update the references and text to incorporate new work that has been completed since the original compilation period.

AAPG Studies in Geology↗

Geophysical Interpretations of the Southern Espanola Basin, New Mexico, That Contribute to Understanding Its Hydrogeologic Framework

The southern Espanola basin consists of a westward- and northward-thickening wedge of rift fill, composed primarily of Santa Fe Group sediments, that serves as an important aquifer for the city of Santa Fe and surrounding areas. Detailed aeromagnetic surveys were flown to better understand ground-water resources in this aquifer. This report presents a synthesis of these data with gravity data and other constraints. The interpretations were accomplished using qualitative interpretation, state-of-art data analysis techniques, and two- and three-dimensional modeling. The results depict the presence of and depth to many geologic features that have hydrogeologic significance, including shallow faults, different types of igneous units, and basement rocks. The results are presented as map interpretations, geophysical profile models, and a digital surface that represents the base and thickness of Santa Fe Group sediments, as well as vector files of some volcanic features and faults.

Professional Paper↗

Multi-resource analysis: A proof of concept study of natural resource tradeoffs in the Piceance Basin, Colorado, using the net resources assessment (NetRA) decision support tool

Executive Summary The U.S. Geological Survey (USGS) is developing a multi-resource analysis (MRA) line of products to inform land-use decision makers. Specifically, MRA products will integrate scientific information, include considerations for natural resource interrelations, and quantify the effects of resource management decisions in biophysical, economic, and societal terms. As part of the establishment of the MRA, the USGS, in collaboration with the University of New Mexico, has developed the Net Resources Assessment (NetRA) decision support tool. As a proof of concept analysis, the NetRA was applied to the Piceance basin in Colorado in a hypothetical example to illustrate how resource managers could use the NetRA to consider tradeoffs of natural resources among alternative development plans and land cover patterns within a geographic region. The NetRA is a policy-relevant approach to assess the availability of multiple natural resources. It is an analytical toolset that may be used to examine the spatiotemporal relations between development of energy and mineral resources and delivery of biological natural resources. The NetRA operates at multiple map scales and contains a set of integrated, compatible submodels with specific data requirements for natural resource stocks, engineering economics, biophysical, and ecological data for ecosystem services stocks, market prices, regulations, and nonmarket values. The NetRA includes an explicit process to consider the interdependence between development and conservation, which is a crucial consideration in land-management and land-use decisions. The NetRA is used to estimate an expected net resource value (NRV). The NRV is the expected, present value, economic benefit from the extraction of a resource (for example, natural gas) minus the total cost of production, which is the aggregation of the development, production, and social costs. Social costs include private costs plus any external costs. There can be external social benefits associated with natural gas production, such as increased demand for locally produced goods and increased employment in the local area through backward and forward linkages of natural gas production. The NRV is used to compare development outcomes (scenarios) from a range of exploration and development plans for cumulative energy production. The Piceance basin application of the NetRA uses the NRV to assess the tradeoff between continuous natural gas extraction and the effects to the local populations of Odocoileus hemionus (mule deer) and aquatic species and to consumptive water uses for an area the size and resolution of a USGS energy resource assessment unit. In the proof of concept simulation, the 2.9-square-mile-area of USGS oil and gas assessment unit 50200263 (Piceance basin continuous gas unit of the Mesaverde Total Petroleum System) was gridded into 588 cells. From this area, seven clusters with potential for development and three that cannot be developed were identified; the three clusters that cannot be developed were identified as wilderness study areas, areas of critical environmental concern, and national forests. On the basis of these criteria, there are 118 cells unsuitable for development in the oil and gas assessment unit: 84 are in national forests, 23 are areas of critical environmental concern, and 11 are wilderness study areas. The remaining cells in the oil and gas assessment unit can be developed on both private and public lands. Two scenarios were considered that are distinguished as plan 1 and plan 2. Plan 1 keeps the amount of land disturbance unchanged and limits the number of development locations to 140 grid cells for the production period, which constrains the amount of the energy resources available for development; the plan requires the usage of the Bureau of Land Management (BLM) unsuitability criteria. Plan 2 also limits the number of development locations to 140 grid cells for the production period but provides a constant volume of energy production by increasing the density of well pads within the cells. The effects of plan 2 to the NRV when there are five wells per pad and five pads per square mile happen mostly in the first 5 years of development, even though the effects on the population of mule deer continue in later years. This outcome is the result of the upfront development and investment costs and the initial effect to the ecosystem services.

Colorado↗

Background and geologic model for the 2024 U.S. Geological Survey assessment of undiscovered conventional petroleum resources in the Norphlet Formation, U.S. Gulf Coast

The Upper Jurassic Norphlet Formation is a stratigraphic unit located in the subsurface of the United States Gulf coastal plain and offshore Gulf of America (Gulf of Mexico). The Norphlet consists of clastic sediments derived from the southern Appalachian highlands, and was deposited in a continental dryland setting on the margins of the early Gulf of America rift basin. The formation contains a variety of sedimentary facies, including facies representing updip alluvial fans, wadis, red beds, and a widespread erg, or eolian sand sea. The erg facies form the primary reservoirs from which hydrocarbons sourced from the overlying Smackover Formation are produced. Development of the Norphlet began in earnest in the late 1960s, with new discoveries, including large fields at Flomaton, Hatters Pond, and Mobile Bay, continuing through the 2000s–2010s with the discovery of major oil fields in the offshore Desoto Canyon area. Onshore, Norphlet hydrocarbon traps typically are faulted salt anticlines, although many fields also have a stratigraphic trapping component because of the preservation of dune-scale bedforms. Thermal maturity across the Norphlet play varies significantly with depth, resulting in oil production transitioning downdip to natural gas liquids production, then dry gas production; production depths reach to greater than 21,000 feet. A 2024 U.S. Geological Survey assessment divided the Norphlet into four conventional assessment units defined by the type and frequency of trapping mechanisms, sedimentology, and thermal maturity of each area, with little potential for hydrocarbon development observed west of the Mississippi River. Although petroleum resources in the Norphlet were revised downward, it is probable that significant resources remain to be discovered.

Alabama, Florida, Mississippi↗

Preface: Marine gas hydrate reservoir systems along the eastern continental margin of India: Results of the National Gas Hydrate Program Expedition 02

The 2015 India National Gas Hydrate Program (NGHP) Expedition 02 was conducted to obtain new information on the occurrence of gas hydrate systems and to advance the understanding of geologic controls on the formation of gas hydrate accumulations in the offshore of India. The ultimate goal of the NGHP effort is to assess the energy resource potential of marine gas hydrates in India. The Guest Editors for this special thematic issue of the Journal of Marine and Petroleum Geology (JMPG) have worked with more than 100 scientists and engineers to prepare the 45 individual reports included in this special issue to address the operational and technical contributions of the NGHP-02 Expedition. This thematic issue on natural gas hydrates in the offshore of India is built on the foundation of five previous JMPG thematic issues that focused on the scientific results of other marine gas hydrate expeditions. These foundational contributions include: (1) the “Scientific Results of the 2005 USDOE-Chevron JIP Drilling for Methane Hydrates Objectives in the Gulf of Mexico” (Volume 25, Issue 9, November 2008), (2) the “Resource and Hazard Implications of Gas Hydrates in the Northern Gulf of Mexico: Results of the 2009 Joint Industry Project Leg II Drilling Expedition” (Volume 34, Issue 1, June 2012), (3) the “Scientific Results of the Second Gas Hydrate Drilling Expedition in the Ulleung Basin (UBGH2), East Sea of Korea” (Volume 47, November 2013), (4) “Geologic Implications of Gas Hydrates in the Offshore of India: Results of the National Gas Hydrate Program Expedition 01” (Volume 58, Part A, December 2014), and (5) “Gas Hydrate Drilling in Eastern Nankai” (Volume 66, Part 2, September 2015). The NGHP-02 Expedition was conducted from 03-March- 2015 to 28-July- 2015 off the eastern coast of India. The first two months of the expedition were dedicated to establishing 25 new research sites that featured the drilling of a dedicated downhole logging hole at each site. The next three months of the NGHP-02 Expedition were dedicated to sediment coring and other downhole measurement operations at 10 of the sites established during the expedition’s first phase. The results of downhole logging, coring and formation pressure testing operations during NGHP-02 have confirmed the presence of large, highly concentrated gas hydrate accumulations in coarse-grained, sand-rich depositional systems throughout large portions of the Krishna-Godavari Basin. Post expedition research and reporting efforts included collaborative analysis of the unprecedented number of shipboard acquired data sets and core samples obtained during NGHP-02. The presentation of the scientific results of the NGHP-02 Expedition has culminated in the publication of the NGHP Expedition 02 Scientific Results Volume, which is represented by this Special Issue of the Journal of Marine and Petroleum Geology. This Special Issue features a series of four reports that summarize the operational and scientific results of NGHP-02 Expedition that are presented in the 41 technical reports included this Special Issue. The first summary report, “India National Gas Hydrate Program Expedition 02: Operational and Technical Summary,” focuses on reviewing the tools and operational procedures for the NGHP-02 Expedition that led to the acquisition of an unprecedented amount of high-quality downhole logging and core data from numerous pore-filling, fracture-filling, and sediment-displacement type gas hydrate occurrences. The summary report titled “India National Gas Hydrate Program Expedition 02 Summary of Scientific Results: Gas Hydrate Systems Along the Eastern Continental Margin of India” documents gas hydrate occurrences discovered during the NGHP-02 Expedition and examines geologic controls on the gas hydrate systems along the Eastern Continental Margin of India.

Journal of Marine and Petroleum Geology↗

Assessment of soil and water resources in the Organ Mountains-Desert Peaks National Monument, New Mexico

The Organ Mountains-Desert Peaks National Monument (Monument) in southern New Mexico was established in 2014. Given anticipated future demands in the Monument for recreation, livestock grazing, and maintenance of rights-of-way (for example, pipelines and powerlines), the Bureau of Land Management (BLM) needs a better understanding of the current soil and water resources and how infrastructure improvements could affect these resources and the watershed. Specifically, the BLM is concerned with infiltration and erosion and their relations to existing or planned infrastructure, such as roads, campgrounds, location of livestock grazing, and rights-of-way. Alternatives to the current land-use conditions, land-management practices, and infrastructure will be assessed by BLM to best protect Monument resources. The U.S. Geological Survey, in cooperation with the BLM, conducted a study to assess the soil and water resources within the Monument to provide an inventory and compilation of natural-resource information needed by resource managers for the BLM’s land-use planning process for this new national monument. The overall objectives of this study were to (1) compile and interpret existing soil- and water-resource data for the Monument and (2) provide a basic assessment of the surface hydrological effects of selected alternatives to current land use and infrastructure. Data were compiled by using geographic information system software and evaluated for hydrologic and landscape properties that influence infiltration, runoff, and erosion. The effects of changing vegetation were simulated by using different scenarios in the Rangeland Hydrology and Erosion Model. Results of this model indicate areas where soil loss or runoff may occur.

New Mexico↗

Geophysical constraints on Rio Grande rift structure in the central San Luis Basin, Colorado and New Mexico

Interpretation of gravity, aeromagnetic, and magnetotelluric (MT) data reveals patterns of rifting, rift-sediment thicknesses, distribution of pre-rift volcanic and sedimentary rocks, and distribution of syn-rift volcanic rocks in the central San Luis Basin, one of the northernmost major basins that make up the Rio Grande rift. Rift-sediment thicknesses for the central San Luis Basin determined from a three-dimensional gravity inversion indicate that syn-rift Santa Fe Group sediments have a maximum thickness of ~2 km in the Sanchez graben near the eastern margin of the basin along the central Sangre de Cristo fault zone, and reach nearly 1 km within the Monte Vista graben near the western basin margin along the San Juan Mountains. In between, Santa Fe Group thickness is negligible under the San Luis Hills and estimated to reach ~1.1 km under the Costilla Plains (although no independent thickness constraints exist, and a range of thicknesses of 600 m to 2 km is geophysically reasonable). From combined geophysical and geologic considerations, pre-rift, dominantly sedimentary rocks appear to increase in thickness from none in the Sanchez graben on the east to perhaps 800 m under the San Luis Hills on the west. The pre-rift rocks are most likely early Tertiary in age, but the presence of Mesozoic and Paleozoic sedimentary rocks cannot be ruled out. Geophysical data provide new evidence that an isolated exposure of Proterozoic rocks on San Pedro Mesa is rooted in the Precambrian basement. This narrow, north-south–trending basement high has ~2 km of positive relief with respect to the base of the Sanchez graben, and separates the graben from the structural depression beneath the Costilla Plains. A structural high composed of pre-rift rocks, long inferred to extend from under the San Luis Hills to the Taos Plateau, is confirmed and found to be denser than previously believed, with little or no overlying Santa Fe Group sediments. Major faults in the study area are delineated by geophysical data and models; these faults include significant vertical offsets (≥1 km) of Precambrian rocks along the central and southern zones of the Sangre de Cristo fault system. Other faults with similarly large offsets of the Santa Fe Group include a fault bounding the western margin of San Pedro Mesa, and other faults that bound the Monte Vista graben in an area previously assumed to be a simple hinge zone at the western edge of the San Luis Basin. A major north-south–trending structure with expression in gravity and MT data occurs at the boundary between the Costilla Plains and the San Luis Hills structural high. Although it has been interpreted as a down-to-the-east normal fault or fault zone, our modeling suggests that it also is likely related to pre-rift tectonics. Aeromagnetic anomalies over much of the area are interpreted to mainly reflect variations of remanent magnetic polarity and burial depth of the 5.3–3.7 Ma Servilleta Basalt of the Taos Plateau volcanic field. Magnetic-source depth estimates are interpreted to indicate patterns of subsidence following eruption of the basalt, with maximum subsidence in the Sanchez graben.

Colorado, New Mexico↗

Twenty-Sixth Annual Report of the Director of the United States Geological Survey, 1904-1905

Introduction Remarks on the work of the year Branches of work The United States Geological Survey was created in 1879 for the purpose—as its name implies—of examining and reporting on the geologic structure and mineral resources and products of the national domain. To the adequate description of geologic formations and structure cartography is essential, and Congress early recognized this fact by making appropriations for the preparation of a geologic map of the United States. The topographic base map, in order to show with sufficient precision the relations of the geologic formations and the intricacies of the structure, must have a rather large scale and present considerable detail. No such map of this country existed in 1879, and its preparation was immediately begun. The waters of the country are of vast importance, and in a broad sense may be regarded as one of its greatest mineral resources. Hence, in the evolution of the work of the Survey, and especially in view of the great importance of the subject to the irrigation interests, Congress early began making appropriations for ascertaining the amount and quality of the surface and underground waters and when, in 1902, the service for the reclamation of arid lands was organized, that work naturally was placed in the hands of the Secretary of the Interior and by him intrusted to the Director of the Survey. The three great branches of work carried on by the Geological Survey are, therefore, the geologic, the topographic, and the hydrographic, and with these, more especially the latter, is conjoined the Reclamation Service ; publication and administration constitute necessary auxiliary branches. Along these great lines the work of the Survey has progressed without essential variation for many years. The changes made have been due to normal expansion rather than to radical departure in object or plan. State cooperation During the last fiscal year, State cooperation, as explained in previous reports, continued. Arrangements for cooperation in geologic work were made with five States, the total amount contributed by them being about \$8,000, and arrangements for cooperative topographic surveys were made with eleven States, the amount available for such surveys being thus increased by more than \$100,000. Reclamation service The work of the Reclamation Service during the last fiscal year was advanced as rapidly as was thought consistent with thoroughness and accuracy. Actual construction is now in progress on eight projects, as follows : Salt River, Arizona; Truckee-Carson, Nevada; Hondo, New Mexico ; Uncompahgre Valley, Colorado; Minidoka, Idaho; Belle Fourche, South Dakota ; North Platte, Wyoming and Nebraska ; and Shoshone, Wyoming. Proposals were received for work on the Laguna dam, Yuma project, California and Arizona; Huntley project, Montana, and the Fort Buford project, North Dakota and Montana. In several other States operations are at a point where advertisements for bids only await the removal of certain legal obstacles, the settlement of international difficulties, or the termination of delays on the part of local organizations or individuals. The organization of the body of men constituting the personnel of the Reclamation Service, whose field of operations covers so large a territory, though necessarily difficult, has been satisfactorily accomplished, and precedents have been established along approved lines. The general allotment of funds has been made with a view to the greatest benefit to the greatest number, and from the broad standpoint of the welfare of the country as a whole. One of the important features in the evolution of the irrigation work is the development of power, which the numerous dams and, drops in canals make possible. Plans were made to transmit the power being developed in many sections of the arid regions, by means of electricity, to points more or less distant, there to be used for raising underground waters, pumping waters lying above the line of gravity canals, or for various other purposes, and attention was also given to the character of the soils and of the water to be used upon them, the materials used in the construction of the works, and numerous other details incident to reclamation by irrigation. Coal-testing plant Under two special appropriations of \$30,000 each, carried by the urgent deficiency bill approved February 18, 1904, and the general deficiency bill approved April 27, 1904, the Director of the Geological Survey was authorized to construct and operate at the Louisiana Purchase Exposition a plant for testing the coals and lignites of the United States, in order to determine their fuel values and the most economic method of their utilization for different purposes, it being provided that all testing machinery and all coals and lignites to be tested 'should be contributed free of charge to the Government. For carrying out the provisions of these acts the Director appointed a committee, consisting of Edward W. Parker, Joseph A. Holmes, and Marius R. Campbell, to direct the construction and operation of the plant. This committee received the heartiest cooperation from the manufacturers of such equipment as was needed for the installation of the plant, from the railroad companies in freight concessions and transportation for the experts and their assistants, and from the coal operators in the furnishing of coal in carload lots for testing purposes. Although the utmost expedition was used in the construction of the plant, it was not until the first of September that the testing work actually began. Between the first of September and the close of the exposition 65 carload samples of coal for testing purposes were received, and the results of the investigation were published in a preliminary report issued as Geological Survey Bulletin No. 261. The coals tested were received from 17 States and Territories, and much valuable information regarding the best uses to which the different coals may be put was obtained. One of the most important facts developed during this investigation is the possibility of utilizing the vast lignite resources of the West in the manufacture of producer gas, it having been shown that a higher grade of this gas can be obtained from lignite than from ordinary bituminous and anthracite coal. The investigation also showed that the slack or fine coal produced at the dry, noncoking bituminous coal mines of the middle West, large quantities of which are now being wasted, can be profitably utilized by briquetting.

Annual Report↗

Field-trip guide to continental arc to rift volcanism of the southern Rocky Mountains—Southern Rocky Mountain, Taos Plateau, and Jemez Mountains volcanic fields of southern Colorado and northern New Mexico

The southern Rocky Mountains of northern New Mexico and southern Colorado preserve the Oligocene to Pleistocene record of North American continental arc to rift volcanism. The 35–23 million year old (Ma) southern Rocky Mountain volcanic field (SRMVF), spectacularly preserved in the San Juan Mountains of southern Colorado, records the evolution of large andesitic stratovolcanoes to complex caldera clusters, from which at least 22 major ignimbrite sheets (each 150–5,000 cubic kilometers) were erupted. Outflow deposits of the SRMVF preserved along the broadly uplifted northwest flank of the northern Rio Grande rift basin (the San Luis Valley) provide critical structural and temporal constraints on the inception of crustal extension. Coincident with waning stages of SRMVF caldera-forming volcanism (~25.4 Ma), extensional tectonism was accompanied by a transition from bimodal early Miocene to intermediate-composition late Miocene and dominantly basaltic Pliocene rift volcanism of the Taos Plateau in the southern San Luis Basin. Concomitant rift volcanism in the Española Basin and bordering Jemez Mountains of northern New Mexico records a similar Miocene eruptive history dominated by intermediate-composition volcanism that transitioned locally to Pliocene rift-related basaltic volcanism of the Cerros del Rio volcanic field and culminated in eruptions of the iconic rhyolitic Pleistocene Bandelier Tuff and formation of the Valles Caldera along the northwestern rift-basin margin. This 6-day, 7-night field trip will focus, in broadly equal proportions, on rift-related extensional volcanism of the Jemez Mountains and Taos Plateau regions during the first half of the trip, and on caldera-forming volcanism of the southern Rocky Mountain volcanic field during the second half of the trip. The 35-million-year volcanic history of the region highlighted by new geologic mapping, high-resolution geochronology, petrologic, geochemical, and geophysical data facilitates discussion of (1) the magmatic response to the tectonic transition from subducted-slab arc to continental-rift volcanism; (2) the nature and temporal evolution of rift magmas; (3) fault controls on the spatial evolution of rift magmatism; (4) the diversity of continental-arc ignimbrite volcanism and associated lavas; (5) ignimbrite caldera structure and associated intrusions in three-dimension; (6) the role of recycled crystal mush and magmatic cumulates during growth of Cordilleran batholiths; and (7) high-precision geochronologic contributions to interpretation of relations between regional tectonic and volcanic processes. Most stops will be along roads, but there will be moderate hikes on trails of less than 1-hour duration covering 1–2 kilometers (0.6–1.2 miles) with modest elevation gain of <150 meters (<492 feet). The route will progress in reverse stratigraphic order, starting in the Jemez Mountains of New Mexico and proceed northward to San Luis Basin and San Luis Hills before turning west to the southeast and central San Juan Mountains. Our last full day takes us to the little-visited and only recently mapped, Bonanza caldera of the northeastern San Juan Mountains and on the final day, we leave the San Luis Valley to briefly explore the Tertiary subvolcanic plutons of the Collegiate Range along the west side of the Arkansas Valley rift valley, en route to Denver. The authors of all daily contributions acknowledge the helpful reviews by Amy Gilmer and Joe Colgan and thank Christine Chan and Jeremy Havens for assistance with figures, tables, and guidebook text.

Colorado, New Mexico↗

Colorado Plateau

Field studies in the Colorado Plateau occupy an honored place in the development of geomorphic theory. The purpose of this chapter is to briefly review the foundational, regional, and process-oriented studies in the region, and to provide a review of promising threads of inquiry set in a context of more than a century of geomorphologic research in the region. The Colorado Plateau has sharply defined boundaries that separate it from neighboring geomorphic provinces (Fig. 1; for details see Thornbury, 1965). On the west, faults and the perimeters of volcanic plateaus mark the boundary between the Colorado Plateau and the Basin and Range Province. The boundary extends across the southern edge of the plateau where it is less radically defined, but is nonetheless visible on the surface in the form of an uplifted edge of sedimentary rocks known as the Mogollon Rim, which extends from northwest Arizona diagonally into north-central New Mexico. The eastern and northern boundaries are delineated by the contact between sedimentary rocks and upthrust or folded crystalline rocks of the Rocky Mountains. The plateau is a definable tectonic unit relatively easily separated from other provinces, but it shows considerable internal variation (Fig. 1; for details see Hunt, 1974a). The interior of the kidney-shaped Colorado Plateau Province reveals a series of subsections that depend on geologic and geomorphologic definition. The centrally located Canyon Lands Section is dominated by gently folded sedimentary rocks, while the western High Plateaus Section reveals widespread accumulations of volcanic materials.

Arizona, Colorado, New Mexico, Utah↗

Evidence for the recovery of terrestrial ecosystems ahead of marine primary production following a biotic crisis at the Cretaceous-Tertiary boundary

The fossil record demonstrates that mass extinction across the Cretaceous–Tertiary (K–T) boundary is more severe in the marine than the terrestrial realm. We hypothesize that terrestrial ecosystems were able to recover faster than their marine counterparts. To test this hypothesis, we measured sedimentary δ 13 C as a tracer for global carbon cycle changes and compared it with palaeovegetational changes reconstructed from palynomorphs and cuticles across the K–T boundary at Sugarite, New Mexico, USA. Different patterns of perturbation and timescales of recovery of isotopic and palaeobotanical records indicate that the δ 13 C excursion reflects the longer recovery time of marine versus terrestrial ecosystems.

New Mexico↗

Geology along Mosca Pass Trail, Great Sand Dunes National Park and Preserve, Colorado

Mosca Pass Trail takes the hiker on a journey into the Earth's crust. Here you can see the results of tremendous tectonic forces that bend and tear rocks apart and raise mountain ranges. The trail begins near the Sangre de Cristo fault, which separates the Sangre de Cristo Range from the San Luis Valley. The valley is part of the Rio Grande rift, a series of fault basins extending from southern New Mexico to central Colorado, wherein the Earth's crust has been pulled apart during the last 30 million years. Thousands of feet of sediment, brought by streams mostly from the Sangre de Cristo Range, fill the San Luis Valley beneath the Great Sand Dunes. The trail ends at Mosca Pass overlooking Huerfano Park. The park is part of the larger Raton Basin, formed by compression of the Earth's crust during the Laramide orogeny, which occurred 70&ndash;40 million years ago. Massive highlands, the remnants of which are preserved in the Sangre de Cristo Range, were uplifted and pushed over the western side of the Raton Basin. Streams eroded the highland as it rose and filled the Raton Basin with sediment. After the sediment was compacted and cemented to form sedimentary rock, the Huerfano River and other streams began to excavate the basin. Over an unknown but long timespan that probably lasted millions of years, relatively soft sedimentary rocks were removed by the river to form the valley we call "Huerfano Park." Between the ends of the trail, the hiker walks through an erosional "window," or opening, into red sedimentary rocks overridden by gneiss, a metamorphic rock, during the Laramide orogeny. This window gives the hiker a glimpse into the Laramide highland of 70&ndash;40 million years ago that preceded the present-day Sangre de Cristo Range. The window is the focus of this trail guide. At the east end of the trail, near Mosca Pass, another trail follows the ridgeline south to Carbonate Mountain. Immediately after reaching the first summit above tree line, this trail crosses a narrow valley where red rocks mark an extension of the window across the range. Stunning vistas of the Sangre de Cristo Range extend north to the horizon. The uplifted range stands in sharp contrast to the San Luis Valley on the west and Huerfano Park on the east.

Colorado↗

Geochemical, modal, and geochronologic data for 1.4 Ga A-type granitoid intrusions of the conterminous United States

Introduction The purpose of this report is to present available geochemical, modal, and geochronologic data for approximately 1.4 billion year (Ga) A-type granitoid intrusions of the United States and to make those data available to ongoing petrogenetic investigations of these rocks. A-type granites, as originally defined by Loiselle and Wones (1979), are iron-enriched granitoids (synonymous with the ferroan granitoids of Frost and Frost, 2011) that occur in an anorogenic, within-continent setting. Relative to other granitic rocks, A-type granites have high FeO*/(FeO*+MgO), high K 2 O and K 2 O/Na 2 O, are metaluminous to weakly peraluminous, and are enriched in incompatible trace elements. Loiselle and Wones (1979) further suggested that A-type granites are relatively anhydrous. Anderson (1983) provides an early compilation of data for the products of 1.4 Ga magmatism in North America and notes the spatial and temporal association of a trio of rock types, which includes gabbro to anorthosite, intermediate composition mangerite, and granitic rapakivi rocks. In North America, the majority of known A-type intrusions were emplaced between 1.5 and 1.3 Ga and are predominantly of the granitic variety (Anderson, 1983). This report addresses the broadly Mesoproterozoic-age granitic rocks of the conterminous United States. Constituents of this group of intrusive rocks were defined using a variety of spatial, compositional, and geochronologic metrics. Thomas and others (2012) provided an updated synthesis, largely based on new isotopic and geochronologic data (for example, Fisher and others, 2010), for the large-scale geologic and tectonic evolution of the eastern United States. Their findings suggest that the basement rocks of the central and southern Appalachian region are allochthonous relative to the remainder of Laurentia and were accreted along the Grenville front between 1.25 and 1.0 Ga. Accordingly, Mesoproterozoic rocks east of the Grenville front and south of the approximate latitude of New York City do not represent North American magmatism. Consequently, geochemical, modal, and geochronologic data for these rocks are not included in the compilation described herein. Further, the structural styles and compositions of granitoid rocks east of the Grenville front, mostly highly deformed gneissic rocks, are dissimilar to those characteristic of the A-type granitoid rocks described herein. A variety of compositional and age information further characterizes the 1.4 Ga A-type granitoid rocks in the conterminous United States. Most samples included in this compilation have felsic compositions, although some extend to intermediate compositions. SiO2 contents range from 56 to almost 78 weight percent, and median and mean SiO2 contents are 72.0 and 71.1 weight percent, respectively. The majority of these rocks for which modal data are available are composed of monzogranite (Streckeisen, 1976), although the dataset also contains many samples composed of granodiorite and syenogranite. A smaller group of the granitoid rocks in this dataset are composed of quartz monzodiorite and quartz monzonite, and a very small subset of samples is composed of alkali-feldspar granite, tonalite, alkali-feldspar quartz syenite, and quartz syenite (fig. 1). Many of the 1.4 Ga granitoid rocks are further characterized by medium- to coarse-grain size and are also conspicuously porphyritic; alkali feldspar phenocrysts or megacrysts (2&ndash;10 cm), often with rapakivi overgrowths, are a common feature of many of these rocks (Anderson, 1983; Anderson and Bender, 1989; Anderson and Cullers, 1978; Condie and Budding, 1979). The age of A-type magmatism in North America ranges from about 1.8 to 1.0 Ga, although Anderson (1983) suggests that more than 70 percent (by volume) of A-type magmatism in this region occurred between 1.49 and 1.41 Ga. In the conterminous United States, ages of A-type granitoid rocks are restricted to the period between about 1.49 and 1.33 Ga (Anderson, 1983; Bauer and Pollock, 1993; Bickford and Mose, 1975; Bickford, Harrower, and others, 1981; Bickford and others, 1989; Dewane and Van Schmus, 2007; Hoppe and others, 1983; Peterman and Hedge, 1968; Van Schmus and Bickford, 1981; Van Schmus and others, 1975). Using these recognition criteria, we identified A-type granitoid intrusions of the conterminous United States; for those intrusions, we compiled available geochemical, modal, isotopic (Sr and Nd) and geochronologic data for inclusion in the databases described herein. The significance of 1.4 Ga granitoid rocks relative to the geologic evolution of the conterminous United States remains unclear, despite Anderson&rsquo;s (1983) compilation and synthesis of compositional data pertinent to these rocks. The large-volume magmatic events indicated by these rocks, as well as their broad geographic distribution, tectonic significance, and association with mineral deposits, underscore their importance. The broad distribution of these rocks, from the northern mid-continent to the southwestern United States (in New Mexico, Arizona, California, and southernmost Nevada), throughout the Rocky Mountains in New Mexico and Colorado (and sporadically in southern Wyoming and central Idaho), and beneath much of the Plains region (as indicated by drilling), has led to the large-scale tectonic and magmatic processes responsible for genesis of the associated magmas being actively studied. In addition, Kisvarsanyi (1972) suggests that iron-copper deposits in the St. Francois Mountains of southeastern Missouri are petrogenetically associated with 1.4 Ga A-type granitoids that occur in that region. Similarly, Dall&rsquo;Agnol and others (2012) summarize important global associations between A-type granitoid rocks and a variety of important ore deposit types, particularly tin, high-field-strength elements (Zr, Hf, Nb, Ta), rare-earth elements, and iron oxide-copper-gold deposits. Consequently, the need to better understand relations between A-type granitoid rocks, tectonic setting, and magma petrogenesis, as well as their genetic associations with important types of ore deposits, suggests that developing a definitive geochemical, modal, and geochronologic database for these rocks in the conterminous United States is of considerable value.

Data Series↗