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At least 1,441 records · Page 80Linked to original sources
USGS2001

The Cretaceous-Tertiary boundary interval in Badlands National Park, South Dakota

A marine K-T boundary interval has been identified throughout the Badlands National Park region of South Dakota. Data from marine sediments suggest that deposits from two asteroid impacts (one close, one far away) may be preserved in the Badlands. These impact-generated deposits may represent late Maestrichtian events or possibly the terminal K-T event. Interpretation is supported by paleontological correlation, sequence stratigraphy, magnetostratigraphy, and strontium isotope geochronology. This research is founded on nearly a decade of NPS approved field work in Badlands National Park and a foundation of previously published data and interpretations. The K-T boundary occurs within or near the base of a stratigraphic interval referred to as the "Interior Zone." We interpret the stratigraphy of the Interior Zone as a series of distinct, recognizable lithologic members and units from oldest to youngest, an upper weathered interval of the Elk Butte Member of the Pierre Shale (early late Maestrichtian), a complete (albeit condensed) interval of Fox Hill Formation, a pedogenically altered K-T Boundary "Disturbed Zone," and a generally unresolved sequence of marine to marginal marine units ranging in age from possibly latest Maestrichtian to late Paleocene (the "Yellow Mounds"), that underlie a basal red clay unit (the late Eocene overbank channel facies of the Chamberlain Pass Formation at the base of the White River Group). Within this sequence is a series of unconformities that all display some degree of subaerial weathering and erosion. The dating of marine fossils above and below these unconformities are in line with generally accepted global sea-level changes recognized for the late Campanian through early Eocene. Within the greater framework of regional geology, these findings support that the Western Interior Seaway and subsequent Cannonball Seaway were dependently linked to the changing base-level controlled by sea-level of the global ocean through the Gulf of Mexico and possibly the Arctic Ocean. The variation of facies preserved in Late Cretaceous strata in the Badlands National Park area were in part controlled by local or regional tectonic blocks that were either rising or sinking contemporaneous with deposition.

South Dakota↗
USGS1973

Shale, mudstone, and claystone as potential host rocks for underground emplacement of waste

In this report, the suitability of the argillaceous formations in the conterminous United States as host rocks for underground waste emplacement is reviewed in terms of available geologic information. The strata are considered mainly according to their dimensions, Depth, composition, permeability, structural and seismic history, and to the extent of drilling in the area. Shale, mudstone, and claystone of marine origin in areas of little structural deformation and seismic risks are generally the most promising. These include the Ohio Shale of Devonian age in northern Ohio and the Devonian-Mississippian Ellsworth Shale and Mississippian Coldwater Shale in Michigan. In-the Rocky Mountain states, the Pierre Shale and other thick shales of Late Cretaceous age are also potential host rocks.

Open-File Report↗
USGS2010

Sedimentation Survey of Lago Patillas, Puerto Rico, March 2007

Lago Patillas is a reservoir located on the confluence of Rio Grande de Patillas and Rio Marin, in the municipality of Patillas in southern Puerto Rico, about 3 kilometers north of the town of Patillas and about 8 kilometers northeast of the town of Arroyo (fig. 1). The dam is owned and operated by the Puerto Rico Electric Power Authority (PREPA) and was constructed in 1914 for the irrigation of croplands in the southern coastal plains of Puerto Rico along the towns of Arroyo, Guayama, Patillas, and Salinas. Irrigation releases are made through the outlet works into the Patillas Irrigation Canal that extends 32.2 kilometers from the Patillas dam to Rio Salinas. The dam is a semi-hydraulic earthfill with a structural height of 44.80 meters, a top width of 4.57 meters, a base width of 190.49 meters, and a crest length of 325.21 meters. The spillway structure is physically separated from the earthfill dam, has an elevation of 58.21 meters above mean sea level, and has three radial arm gates (Puerto Rico Electric Power Authority, 1979). The reservoir impounds the waters of the Rio Grande de Patillas and Rio Marin. The reservoir has a drainage area of 66.3 square kilometers. Additional information and operational procedures are listed in Soler-Lopez and others (1999). During March 14-15, 2007, the U.S. Geological Survey (USGS), Caribbean Water Science Center (CWSC), in cooperation with the PREPA conducted a bathymetric survey of Lago Patillas to update the reservoir storage capacity and update the reservoir sedimentation rate by comparing the 2007 bathymetric survey data with previous 1997 data. The purpose of this report is to update the reservoir storage capacity, sedimentation rates, and areas of substantial sediment accumulation since April 1997.

Lago Patillas;Puerto Rico↗
USGS1998

Mapping the Gulf of Maine with side-scan sonar: A new bottom-type classification for complex seafloors

The bedrock-framed seafloor in the northwestern Gulf of Maine is characterized by extreme changes in bathymetric relief and covered with a wide variety of surficial materials. Traditional methods of mapping cannot accurately represent the great heterogeneity of such a glaciated region. A new mapping scheme for complex seafloors, based primarily on the interpretation of side-scan sonar imagery, utilizes four easily recognized units: rock, gravel, sand and mud. In many places, however, the seafloor exhibits a complicated mixture or extremely 'patchy' distribution of the four basic units, which are too small to map individually. Twelve composite units, each a two-component mixture of the basic units, were established to represent this patchiness at a small scale (1:100,000). Using a geographic information system, these and all other available data (seismic profiles, grab samples, submersible dives and cores) were referenced to a common geographic base, superimposed on bathymetric contours and then integrated into surficial geologic maps of the regional inner continental shelf. This digital representation of the seafloor comprises a multidimensional, interactive model complete with explicit attributes (depth, bottom type) that allow for detailed analysis of marine environments.

Journal of Coastal Research↗
USGS2001

Geological and geochemical characteristics of high arsenic coals from endemic arsenosis areas in southwestern Guizhou Province, China

Southwest Guizhou Province is one of the most important areas of disseminated, sediment-hosted-type Au deposits in China and is an important area of coal production. The chemistry of most of the coals in SW Guizhou is similar to those in other parts of China. Their As content is near the Chinese coal average, but some local, small coal mines contain high As coals. The highest As content is up to 3.5 wt.% in the coal. The use of high As coals has caused in excess of 3000 cases of As poisoning in several villages. The high As coals are in the Longtan formation, which is an alternating marine facies and terrestrial facies. The coals are distributed on both sides of faults that parallel the regional anticlinal axis. The As content of coal is higher closer to the fault plane. The As content of coal changes greatly in different coal beds and different locations of the same bed. Geological structures such as anticlines, faults and sedimentary strata control the distribution of high As coals. Small Au deposits as well as Sb, Hg, and Th mineralization, are found near the high As coals. Although some As-bearing minerals such as pyrite, arsenopyrite, realgar (?), As-bearing sulfate, As-bearing clays, and phosphate are found in the high As coals, their contents cannot account for the abundance of As in some coals. Analysis of the coal indicates that As mainly exists in the form of As5+ and As3+, perhaps, combined with organic compounds. The occurrence of such exceptionally high As contents in coal and the fact that the As is dominantly organically associated are unique observations. ?? 201 Elsevier Science Ltd.

Conference Paper↗
USGS2024

Field geology under the sea with a remotely operated vehicle: Mona Rift, Puerto Rico

We implemented concepts of field geology at great ocean depths by constructing virtual outcrops from a string of overlapping video frames collected by remotely operated vehicles (ROVs). This lower-cost alternative to drilling boreholes allows stratigraphic extension into the offshore and regional interpretation of marine seismic profiles. The imagery was collected along a dive transect on the western wall of Mona Rift, a deep and narrow rift northwest of Puerto Rico, between water depths of 1560 m and 3927 m. The northern coast of Puerto Rico and its large offshore area are underlain by a mid-Eocene and younger forearc basin topped by a thick carbonate platform. There are no drill holes offshore, and tying seismic lines across the shoreline there is problematic. We describe our virtual outcrop and constrain its age and stratigraphy using seven rock samples collected by ROV and compare the outcrop's stratigraphy to deep boreholes and outcrops on land. Our formation descriptions and ages agree, for the most part, with those on land, but we identified a 100-m-thick section that is represented on land by an unconformity. Our stratigraphic interpretation indicates lateral variations in formation thicknesses and establishes a cross-section for additional sampling of the Eocene–Pliocene geology. It also suggests that Mona Rift has formed since the mid-Pliocene. The presence or absence of ferromanganese (Fe-Mn) crust on rocks along the transect may be correlated with the smoothness of the rock surface.

Mona Rift, Puerto Rico↗
USGS1999

Clathrate eustasy: Methane hydrate melting as a mechanism for geologically rapid sea-level fall

Although submarine methane hydrates or clathrates have been highlighted as potential amplifiers of modern global climate change and associated glacio-eustatic sea-level rise, their potential role in sea-level fall has not been appreciated. Recent estimates of the total volume occupied by gas hydrates in marine sediments vary 20-fold, from 1.2 × 10 14 to 2.4 × 10 15 m 3 . Using a specific volume change on melting of −21%, dissociation of the current global inventory of hydrate would result in a decrease of submarine hydrate volume of 2.4 × 10 13 to 5.0 × 10 14 m 3 . Release of free gas bubbles present beneath hydrates would increase these volumes by 1.1–2.0 × 10 13 m 3 . The combined effects of hydrate melting and subhydrate gas release would result conservatively in a global sea-level fall of 10–146 cm. Such a mechanism may offset some future sea-level rise associated with thermal expansion of the oceans. It could also explain anomalous sea-level drops during ice-free periods such as the early Eocene, the Cretaceous, and the Devonian.

Geology↗
USGS2017

Stratigraphic cross sections of the Niobrara interval of the Cody Shale and associated rocks in the Wind River Basin, central Wyoming

The Wind River Basin in Wyoming is one of many structural and sedimentary basins that formed in the Rocky Mountain foreland during the Laramide orogeny. The basin is nearly 200 miles long, 70 miles wide, and encompasses about 7,400 square miles in central Wyoming. The basin is bounded by the Washakie Range, Owl Creek uplift, and southern Bighorn Mountains on the north, the Casper arch on the east, the Granite Mountains on the south, and Wind River Range on the west. Many important conventional oil and gas fields producing from reservoirs ranging in age from Mississippian through Tertiary have been discovered in this basin. In addition, an extensive unconventional overpressured basin-centered gas accumulation has been identified in Cretaceous and Tertiary strata in the deeper parts of the basin. It has long been suggested that various Upper Cretaceous marine shales, including the Cody Shale, are the principal hydrocarbon source rocks for many of these accumulations. With recent advances and success in horizontal drilling and multistage fracture stimulation, there has been an increase in exploration and completion of wells in these marine shales in other Rocky Mountain Laramide basins that were traditionally thought of only as hydrocarbon source rocks. The two stratigraphic cross sections presented in this report were constructed as part of a project carried out by the U.S. Geological Survey to characterize and evaluate the undiscovered continuous (unconventional) oil and gas resources of the Niobrara interval of the Upper Cretaceous Cody Shale in the Wind River Basin in central Wyoming. The primary purpose of the cross sections is to show the stratigraphic relationship of the Niobrara equivalent strata and associated rocks in the lower part of the Cody Shale in the Wind River Basin. These two cross sections were constructed using borehole geophysical logs from 37 wells drilled for oil and gas exploration and production, and one surface section along East Sheep Creek near Shotgun Butte in the northwestern part of the basin. Both lines originate at the East Sheep Creek surface section and end near Clarkson Hill in the extreme southeastern part of the basin. The stratigraphic interval extends from the upper part of the Frontier Formation to the middle part of the Cody Shale. The datum is the base of the “chalk kick” marker bed, a distinctive resistivity peak or zone in the lower part of the Cody Shale. A gamma ray and (or) spontaneous potential (SP) log was used in combination with a resistivity log to identify and correlate units. Marine molluscan index fossils collected from nearby outcrop sections were projected into the subsurface to help determine the relative ages of the strata and aid in correlation.

Wyoming↗
USGS1984

Regional variations in the fluvial Upper Devonian and Lower Mississippian(?) Kanayut Conglomerate, Brooks Range, Alaska

The wholly allochthonous Upper Devonian and Lower Mississippian(?) Kanayut Conglomerate is one of the most extensive fluvial deposits in North America. It crops out for 950 km along the crest of the Brooks Range in a series of thrust plates and is as thick as 2615 m. The Kanayut forms the fluvial part of a large, coarse-grained delta. The lower part of the Kanayut (the Ear Peak Member) overlies marginal-marine and prodelta turbidite deposits and consists of fining-upward meandering-stream-channel cycles of conglomerate and sandstone within black to maroon floodplain shale deposits. The middle part of the Kanayut (the Shainin Lake Member) lacks shale and consists of fining-upward couplets of channelized conglomerate and parallel- to cross-stratified sandstone interpreted as braidplain deposits. These deposits contain the largest clasts (23 cm) and were deposited during maximum progradation of the fluvial sequence. The upper part of the Kanayut (the Stuver Member), which consists of fining-upward meandering stream cycles similar to those of the lower part, grades upward into overlying Lower Mississippian tidal and marginal-marine deposits. Paleocurrent data and distribution of largest clasts indicate that the Kanayut was deposited by southwest-flowing streams fed by at least two major trunk streams that drained a mountainous region to the north and east. Comparison of stratigraphic and sedimentologic data collected at three selected locations representative of proximal, intermediate and distal parts of the Kanayut basin reveal regional variations in its fluvial character. These include a decrease in total thickness of fluvial strata, an increase in total thickness of associated marine sandstone, the pinch-out of the coarse-grained middle part of the Kanayut and decreases in the conglomerate/sandstone and sandstone/shale ratios from proximal to distal areas of the basin. The coarse-grained parts of the fluvial cycles decrease in thickness and lateral extent from proximal to distal areas of the basin. In more distal areas of sedimentation, the middle parts of some fluvial cycles consist of calcareous and bioturbated marine sandstone. Although thinner than in more proximal areas, the associated fine-grained upper parts of some cycles also contain marine features and suggest that these strata represent the deposits of interdistributary bays. These features are interpreted to indicate that the proximal deposits of the Kanayut Conglomerate were deposited by large, stable fine-grained meandering rivers (the Ear Peak and Stuver Members) and gravelly braided rivers (Shainin Lake Member) on the upper delta plain of the Kanayut delta. Sedimentation in more distal locations, interpreted to represent lower delta plain deposits, was by smaller distributary rivers with characteristics of both braided and meandering streams. Near their interface with marginal marine deposits the fluvial deposits were locally strongly influenced by tidal or estuarine conditions. ?? 1984.

Sedimentary Geology↗
USGS2017

Geochronology and paleoenvironment of pluvial Harper Lake, Mojave Desert, California, USA

Accurate reconstruction of the paleo-Mojave River and pluvial lake (Harper, Manix, Cronese, and Mojave) system of southern California is critical to understanding paleoclimate and the North American polar jet stream position over the last 500 ka. Previous studies inferred a polar jet stream south of 35°N at 18 ka and at ~ 40°N at 17–14 ka. Highstand sediments of Harper Lake, the upstream-most pluvial lake along the Mojave River, have yielded uncalibrated radiocarbon ages ranging from 24,000 to > 30,000 14 C yr BP. Based on geologic mapping, radiocarbon and optically stimulated luminescence dating, we infer a ~ 45–40 ka age for the Harper Lake highstand sediments. Combining the Harper Lake highstand with other Great Basin pluvial lake/spring and marine climate records, we infer that the North American polar jet stream was south of 35°N about 45–40 ka, but shifted to 40°N by ~ 35 ka. Ostracodes ( Limnocythere ceriotuberosa ) from Harper Lake highstand sediments are consistent with an alkaline lake environment that received seasonal inflow from the Mojave River, thus confirming the lake was fed by the Mojave River. The ~ 45–40 ka highstand at Harper Lake coincides with a shallowing interval at downstream Lake Manix.

California↗
USGS1999

Connecting onshore and offshore near-surface geology: Delaware's sand inventory project

Beginning in 1988, the Delaware Geological Survey began a program to inventory on-land sand resources suitable for beach nourishment. The inventory included an assessment of the native beach textures using existing data and developing parameters of what would be considered suitable sand textures for Delaware's Atlantic beaches. An assessment of the economics of on-land sand resources was also conducted, and it was determined that the cost of the sand was competitive with offshore dredging costs. In addition, the sand resources were put into a geologic context for purposes of predicting which depositional environments and lithostratigraphic units were most likely to produce suitable sand resources. The results of the work identified several suitable on-land sand resource areas in the Omar and Beaverdam formations that were deposited in barrier-tidal delta and fluvial-estuarine environments, respectively. The identified on-land resources areas have not been utilized due to difficulties of truck transport and development pressures in the resource areas. The Delaware Geological Survey's participation in years 8, 9, and 10 of the Continental Margins Program was developed to extend the known resource areas onshore to offshore Delaware in order to determine potential offshore sand resources for beach nourishment. Years 8 and 9 involved primarily the collection of all available data on the offshore geology. These data included all seismic lines, surface grab samples, and cores. The data were filtered for those that had reliable locations and geologic information that could be used for geologic investigations. Year 10 completed the investigations onshore by construction of a geologic cross-section from data along the coast of Delaware from Cape Henlopen to Fenwick. This cross section identified the geologic units and potential sand resource bodies as found immediately along the coast. These units and resources are currently being extended offshore and tied to known and potential sand resources as part of the continuing cooperative effort between the Delaware Geological Survey and the Minerals Management Service's INTERMAR office as sand resources are identified in federal waters off Delaware. Offshore sand resources are found in the Pliocene Beaverdam Formation offshore where overlying Quaternary units have been stripped, in the tidal delta complexes of several Quaternary units likely equivalent to the onshore Omar Formation, and in late Pleistocene- and Holocene-age shoal complexes. Onshore lithostratigraphic units can be traced offshore and show another reason for continued geologic mapping both onshore and offshore.The Delaware Geological Survey's participation in years 8, 9, and 10 of the Continental Margins Program was developed to extend the known resource areas onshore to offshore Delaware in order to determine potential offshore sand resources for beach nourishment. Years 8 and 9 involved primarily the collection of all available data on the offshore geology. These data included all seismic lines, surface grab samples, and cores. The data were filtered for those that had reliable locations and geologic information that could be used for geologic investigations. Year 10 completed the investigations onshore by construction of a geologic cross-section from data along the coast of Delaware from cape Henlopen to Fenwick.

Marine Georesources and Geotechnology↗
USGS2019

Estimating the degree to which distance and temperature differences drive changes in fish community composition over time in the upper Mississippi River

Similarity in community composition declines as distance between locations increases, a phenomenon that has been observed in a wide variety of freshwater, marine and terrestrial ecosystems. One driver of the distance-similarity relationship is the presence of environmental gradients that alter the suitability of sites for particular species. Although some environmental gradients, such as geology, do not change on a year-to-year basis, others, such as temperature, vary annually and over longer time periods. Here, we used a 21-year dataset of fish communities in the upper Mississippi River to identify the effect of distance on variation in community composition and to assess whether the effect of distance is primarily due to its effect on thermal regime. Because the Mississippi River is aligned mostly north-to-south, larger distances along the river roughly correspond to larger differences in latitude and therefore temperature. As expected, there was a moderate distance-similarity relationship, suggesting greater distance leads to less similarity. The effect of distance appeared to increase slightly over time. Using a subset of data for which air temperature was available, we found that difference among sites in degree days (a surrogate for thermal regime) was more strongly associated with similarity in community composition than physical distance (river km). Although physical distance presumably incorporates more environmental gradients than just temperature (and other potential mechanisms), temperature alone appears to be more strongly associated with differences in the Mississippi River fish community.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗
USGS1998

Areas contributing ground water to the Peconic Estuary, and ground-water budgets for the north and south forks and Shelter Island, eastern Suffolk County, New York

The Peconic Estuary, at the eastern end of Long Island, has been plagued by a recurrent algal bloom, locally referred to as ?Brown Tide,? that has caused the severe decline of local marine resources. Although the factors that trigger Brown Tide blooms remain uncertain, groundwater discharge has previously been shown to affect surface-water quality in the western part of the estuary. A U.S. Geological Survey groundwater- flow model of the main body of Long Island indicates that a total of about 7.5 x 106 ft3/d (cubic feet per day) of freshwater discharges to the western part of the estuary, but the model does not include the ground-water flow systems on the North and South Forks and Shelter Island, which contribute significant amounts of freshwater to the central and eastern parts of the estuary. The need for information on freshwater discharge to the entire estuary prompted the U.S. Geological Survey to evaluate ground-water discharge from the North and South Forks and Shelter Island. Source areas that contribute ground water to the Peconic Estuary were delineated, and groundwater budgets for these areas were developed, to evaluate the distribution and magnitude of ground-water discharge to the central and eastern parts of the estuary. Contributing-area boundaries that were delineated coincide with the hydraulic boundaries of the fresh ground-water-flow systems of the North and South Forks and Shelter Island; these boundaries are of two types? external (saltwater bodies) and internal (groundwater divides). Hydrologic components that were evaluated include recharge from precipitation, public-supply withdrawal and return flow, and agricultural withdrawal. Values for each of these components were calculated or estimated for the individual freshwater flow subsystems that form each ground-water-budget area, then summed to obtain the total discharge of fresh ground water to tidewater. Ground-water discharge to the Peconic Estuary is about 3.8 x 106 ft3/d from the North Fork, 11 x 106 ft3/d from the South Fork, and 1.7 x 106 ft3/d from Shelter Island. The total contribution to the estuary from these areas is about 16 x 106 ft3/d?roughly twice the total contribution from the main body of Long Island. In contrast to the freshwater contribution from the main body of Long Island, which is concentrated near the head of the estuary, the contributions from the North and South Forks and Shelter Island are distributed along the east-west length of the estuary. Changes in water-table altitude and the resulting changes in total discharge to the Peconic Estuary were estimated from the relative changes in annual mean water level at observation wells. The 1985-95 interval included 7 years (1985-88, 1991- 92, 1995) of generally below-average water-table altitudes that presumably caused similar decreases in ground-water discharge to the estuary; intense Brown Tide blooms coincided with six of these years (1985-88, 1991, 1995), and localized blooms coincided with the remaining year (1992). Watertable altitudes in the remaining 4 years of the 1985-95 interval (1989-90, 1993-94) were nearly average or above average, and presumably produced comparably near-average or increased amounts of ground-water discharge to the estuary; none of these years saw any widespread Brown Tide blooms. Fluctuations in the amounts of ground-water discharge to the estuary appear to affect the occurrence of Brown Tide blooms, although the factors that trigger the blooms have not been determined.

Water-Resources Investigations Report↗
USGS2009

Stratigraphy and conodont biostratigraphy of the uppermost Carboniferous and Lower Permian from the North American Midcontinent

Part A The uppermost Wabaunsee, Admire, Council Grove, and lower Chase Groups of Kansas, Oklahoma, and Nebraska are placed into three third-order depositional sequences: a Gzhelian late-highstand sequence set, a Council Grove transgressive and highstand sequence set, and a Chase transgressive sequence set. Sequences are defined by bounding maximum-exposure surfaces and are placed within the zone of exposure surfaces (typically, stacked paleosols). Conodonts are abundant in open-marine deposits and most marine units have a differing and characteristic faunal make-up. Eleven species are described as new: Streptognathodus binodosus , S. denticulatus , S. elongianus , S. florensis , S. lineatus , S. nevaensis , S. postconstrictus , S. postelongatus , S. robustus , S. translinearis , and S. trimilus . Part B Maximum-marine flooding levels and marine-condensed sections from uppermost Carboniferous and Lower Permian fourth-order (0.1-1 m.y.) depositional sequences of the North American midcontinent reveal a rich stratigraphic succession of species of Streptognathodus and Sweetognathus conodonts that permits high-precision correlation of the Carboniferous-Permian boundary as well as the Asselian-Sakmarian and Sakmarian-Artinskian boundaries. Eleven new species of Streptognathodus are described: Streptognathodus binodosus , S. denticulatus , S. elongianus , S. florensis , S. lineatus , S. nevaensis , S. postconstrictus , S. postelongatus , S. robustus , S. translinearis , and S. trimilus . Seventeen species are redescribed and clarified and include Streptognathodus alius , S. barskovi , S. bellus , S. brownvillensis , S. conjunctus , S. constrictus , S. elongatus , S. farmeri , S. flexuosus , S. fuchengensis , S. fusus , S. invaginatus , S. isolatus , S. longissimus , S. minacutus , S. nodulinearis , and S. wabaunsensis . The correlated level of the Carboniferous-Permian boundary is recognized in the lower part of the Red Eagle Depositional Sequence based on the introduction of Streptognathodus isolatus Chernykh, Ritter, and Wardlaw; Streptognathodus minacutus Barskov and Reimers; Streptognathodus invaginatus Reshetkova and Chernykh; Streptognathodus fuchengensis Zhao; and Streptognathodus nodulinearis Reshetkova and Chernykh. The correlated Carboniferous-Permian boundary occurs in the depositional sequence that represents the maximum-marine highstand of the Council Grove Composite Third Order Sequence. This level represents a significant marine-flooding event that should be correlatable in numerous shelfal sections throughout the world. Although the Asselian-Sakmarian boundary has not been rigorously defined, Sweetognathus merrilli has been informally utilized as a Sakmarian indicator. Due to the ecologically controlled distribution of species of Sweetognathus , we prefer to use a species of Streptognathodus as a defining species. We propose that Streptognathodus barskovi (Kozur) Reshetkova be considered as a potentially defining or ancillary defining species for the Sakmarian Stage. In the North American midcontinent, Streptognathodus barskovi appears in the same depositional sequence with Sweetognathus merrilli in the Eiss (Lower Bader) Depositional Sequence. Historically, Sweetognathus whitei has been used to mark the Sakmarian-Artinskian boundary. In our succession Sweetognathus whitei and Streptognathodus florensis appear in the basal part of the Barneston Depositional Sequence. We suggest that Streptognathodus florensis be further investigated as a possible defining or ancillary defining taxon for the base of the Artinskian Stage. This depositional sequence also forms the maximum-marine highstand of the Chase Third-Order Composite Depositional Sequence suggesting that this level is a significant marine-flooding event that should be widely traceable in numerous shelfal sections.

Kansas;Nebraska;Oklahoma↗
USGS1980

Miocene stratigraphy and fossils, Cape Blanco, Oregon.

A summary of the stratigraphic occurrence of the Miocene molluscan faunas exposed in marine sandstone seacliffs on the SW Oregon coast. The more common and biostratigraphically significant species are illustrated. - Philip Harris

Oregon Geology↗
USGS2025

Preprint: Simulated seasonal loads of total nitrogen and total phosphorus by major source from watersheds draining to Washington waters of the Salish Sea, 2005 through 2020

The U.S. Geological Survey (USGS) and the Washington State Department of Ecology (Ecology) have developed watershed models of seasonal load estimates of total nitrogen (TN) and total phosphorus (TP) discharging into the Washington waters of the Salish Sea from 2005 through 2020. The modeling approach used was dynamic SPARROW (SPAtially Referenced Regressions On Watershed attributes), a statistical-physical watershed modeling technique, initially applied at large spatial scales to represent long-term average stream loads throughout a stream network, refined here to estimate seasonal TN and TP loads across watersheds to clarify upstream contributions from discernable point and nonpoint sources delivered to marine waters at surface water confluences along the shoreline and quantify when, where, and why they were high or low. Upstream contributing sources included permitted treated wastewater facilities, crop fertilizer, animal feeding operations, septic systems, urban land and stormwater, atmospheric deposition (TN only), nitrogen fixation by Red Alder Alnus rubra trees (TN only), and background geologic material (TP only). Instream load magnitudes and their source compositions varied widely across watersheds, and even within each watershed, yet the largest loads typically occurred in the large rivers during winter and fall when streamflow was highest. Likewise, instream loads were typically lowest in summer during low streamflow, yet the relative instream aquatic decay was highest. The seasonal storage lag component of those nonpoint sources was estimated to contribute a quarter of the seasonal instream load during winter and fall high streamflow and sometimes half of the instream load during summer low streamflow. A key aspect of Ecology’s current Puget Sound Nutrient Source Reduction Project is consideration of upstream watershed contributions of nutrients to their marine-water discharge points. Simulated seasonal loads carried by streams to 63 river mouth marine discharge points 9 ranged by several orders-of-magnitude for both TN and TP due to the spatial and seasonal differences in hydrologic flows, magnitude and timing of contributing sources, and in-stream decay. The Snohomish and Skagit Rivers discharged the largest TN and TP loads, yet the Samish River was shown to have some of the highest TN and TP yields and concentrations. Additionally, a reference scenario was developed to provide an estimate of the pre-industrial local and regional loads.

ESS Open Archive↗
USGS2009

Geologic Map of the Santa Barbara Coastal Plain Area, Santa Barbara County, California

This report presents a newly revised and expanded digital geologic map of the Santa Barbara coastal plain area at a compilation scale of 1:24,000 (one inch on the map to 2,000 feet on the ground)1 and with a horizontal positional accuracy of at least 20 m. The map depicts the distribution of bedrock units and surficial deposits and associated deformation underlying and adjacent to the coastal plain within the contiguous Dos Pueblos Canyon, Goleta, Santa Barbara, and Carpinteria 7.5' quadrangles. The new map supersedes an earlier preliminary geologic map of the central part of the coastal plain (Minor and others, 2002; revised 2006) that provided coastal coverage only within the Goleta and Santa Barbara quadrangles. In addition to new mapping to the west and east, geologic mapping in parts of the central map area has been significantly revised from the preliminary map compilation - especially north of downtown Santa Barbara in the Mission Ridge area - based on new structural interpretations supplemented by new biostratigraphic data. All surficial and bedrock map units, including several new units recognized in the areas of expanded mapping, are described in detail in the accompanying pamphlet. Abundant new biostratigraphic and biochronologic data based on microfossil identifications are presented in expanded unit descriptions of the marine Neogene Monterey and Sisquoc Formations. Site-specific fault kinematic observations embedded in the digital map database are more complete owing to the addition of slip-sense determinations. Finally, the pamphlet accompanying the present report includes an expanded and refined summary of stratigraphic and structural observations and interpretations that are based on the composite geologic data contained in the new map compilation. The Santa Barbara coastal plain is located in the western Transverse Ranges physiographic province along an east-west-trending segment of the southern California coastline about 100 km (62 mi) northwest of Los Angeles. The coastal plain surface includes several mesas and hills that are geomorphic expressions of potentially active folds and partly buried oblique and reverse faults of the Santa Barbara fold and fault belt (SBFFB) that transects the coastal plain. Strong earthquakes have occurred offshore within 10 km of the Santa Barbara coastal plain in 1925 (6.3 magnitude), 1941 (5.5 magnitude), and 1978 (5.1 magnitude). These and numerous smaller seismic events located beneath and offshore of the coastal plain, likely occurred on reverse-oblique-slip faults that are similar to, or continuous with, Quaternary reverse faults crossing the coastal plain. Thus, faults of the SBFFB pose a significant earthquake hazard to the approximately 200,000 people living within the major coastal population centers of Santa Barbara, Goleta, and Carpinteria. In addition, numerous Quaternary landslide deposits along the steep southern flank of the Santa Ynez Mountains indicate the potential for continued slope failures and mass movements in developed areas. Folded, faulted, and fractured sedimentary rocks in the subsurface of the coastal plain and adjacent Santa Barbara Channel are sources and form reservoirs for economic deposits of oil and gas, some of which are currently being extracted offshore. Shallow, localized sedimentary aquifers underlying the coastal plain provide limited amounts of water for the urban areas, but the quality of some of this groundwater is compromised by coastal salt-water contamination. The present map compilation provides a set of uniform geologic digital coverages that can be used for analysis and interpretation of these and other geologic hazards and resources in the coastal plain region.

Scientific Investigations Map↗
USGS2014

U.S. Geological Survey unconventional petroleum systems research in south Mississippi: Observations on burial history and thermal maturity in the Cretaceous

Shale hydrocarbon ‘resource’ plays have revolutionized the United States energy mix over the last 5 years. These plays are diverse in lithology and age but share the common feature of occurring in ‘tight’ formations which require hydraulic (hydro-) fracturing for economic flow rates. In general, economic success requires an organic-rich reservoir with a quartz- or carbonate-rich mineralogy that responds to artificial stimulation by fracturing. The U.S. Geological Survey (USGS) is tasked with estimating the quantity and quality of undiscovered hydrocarbons reservoired in shales. In support of that mission, we began an investigation of unconventional petroleum systems in the southern part of the Mississippi Salt Basin in 2012, building on earlier reconnaissance work that identified this area as potentially prospective for ‘shale’ gas (Enomoto et al., 2012). While our recent studies (Valentine et al., 2014a; Hackley et al., 2014) have suggested poor ‘shale’ gas prospectivity (due to low organic content, low porosity, high clay content, and significant depth), at least for the Aptian section, they also have generated a wealth of new information about thermal maturity in the Cretaceous of south Mississippi. In addition, our work to-date has set the stage for future USGS evaluation of unconventional hydrocarbons reservoired in the Upper Cretaceous Tuscaloosa Marine Shale (TMS). Here, we summarize recent USGS thermal maturity studies in the south Mississippi Salt Basin.

Mississippi↗