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At least 37 records · Page 2Linked to original sources
USGS2013

Significance of exchanging SSURGO and STATSGO data when modeling hydrology in diverse physiographic terranes

The Water Availability Tool for Environmental Resources (WATER) is a TOPMODEL-based hydrologic model that depends on spatially accurate soils data to function in diverse terranes. In Kentucky, this includes mountainous regions, karstic plateau, and alluvial plains. Soils data are critical because they quantify the space to store water, as well as how water moves through the soil to the stream during storm events. We compared how the model performs using two different sources of soils data--Soil Survey Geographic Database (SSURGO) and State Soil Geographic Database laboratory data (STATSGO)--for 21 basins ranging in size from 17 to 1564 km 2 . Model results were consistently better when SSURGO data were used, likely due to the higher field capacity, porosity, and available-water holding capacity, which cause the model to store more soil-water in the landscape and improve streamflow estimates for both low- and high-flow conditions. In addition, there were significant differences in the conductivity multiplier and scaling parameter values that describe how water moves vertically and laterally, respectively, as quantified by TOPMODEL. We also evaluated whether partitioning areas that drain to streams via sinkholes in karstic basins as separate hydrologic modeling units (HMUs) improved model performance. There were significant differences between HMUs in properties that control soil-water storage in the model, although the effect of partitioning these HMUs on streamflow simulation was inconclusive.

Kentucky↗
USGS1998

Inexpensive automated paging system for use at remote research sites

The use of a flow-activated automatic sampler at a remote research site required personnel to periodically visit the site to collect samples and reset the automatic sampler. To reduce site visits, a cellular telephone was modified for activation by a datalogger. The purpose of this study was to demonstrate the use and benefit of the modified telephone. Both the power switch and the speed-dial button on the telephone were bypassed and wired to a relay driver. The datalogger was programmed to compare values of a monitored environmental parameter with a target value. When the target value was reached or exceeded, the datalogger pulsed a relay driver, activating power to the telephone. A separate relay activated the speed dial, dialing the number of a tone-only pager. The use of this system has saved time and reduced travel costs by reducing the number of trips to the site, without the loss of any data.The use of a flow-activated automatic sampler at a remote research site required personnel to periodically visit the site to collect samples and reset the automatic sampler. To reduce site visits, a cellular telephone was modified for activation by a datalogger. The purpose of this study was to demonstrate the use and benefit of the modified telephone. Both the power switch and the speed-dial button on the telephone were bypassed and wired to a relay driver. The datalogger was programmed to compare values of a monitored environmental parameter with a target value. When the target value was reached or exceeded, the datalogger pulsed a relay driver, activating power to the telephone. A separate relay activated the speed dial, dialing the number of a tone-only pager. The use of this system has saved time and reduced travel costs by reducing the number of trips to the site, without the loss of any data.

Soil Science Society of America Journal↗
USGS2001

Digital terrain modelling and industrial surface metrology - Converging crafts

Quantitative characterisation of surface form, increasingly from digital 3-D height data, is cross-disciplinary and can be applied at any scale. Thus, separation of industrial-surface metrology from its Earth-science counterpart, (digital) terrain modelling, is artificial. Their growing convergence presents an opportunity to develop in surface morphometry a unified approach to surface representation. This paper introduces terrain modelling and compares it with metrology, noting their differences and similarities. Examples of potential redundancy among parameters illustrate one of the many issues common to both disciplines. ?? 2001 Elsevier Science Ltd. All rights reserved.

International Journal of Machine Tools and Manufac↗
USGS1954

U.S. Geological Survey Trace Elements and related reports through 1953

This report combines and brings up-to-date the information previously given in Trace Elements Investigations Report 325, "Numerical list of U.S. Geological Survey Trace Elements Reports to April 30, 1953," and Trace Elements Investigations Report 301, "Topical index and bibliography of U.S. Geological Survey Trace Elements and related reports." Part I is a numerical list of U.S. Geological Survey Trace Elements Investigations and Memorandum reports. It supersedes TEI-325. This part lists not only reports (followed by a date) that have been transmitted to the U.S. Atomic Energy Commission, but also reports in preparation (followed by an asterisk) for which tentative titles were available on December 31, 1953. Reports that have been published are indicated by the abbreviation of the medium of publication. (See also part II.) Part II is a reference guide to Trace Elements and related reports that are available to the public; this part supersedes Part 2 of the TEI-301 (published as Geological survey Circular 281). These reports are grouped according to the type of publication or release. Abstracts published in Nuclear Science Abstracts are not included in Part II, although certain TEI and TEM reports, the abstracts of which have been published in NSA, are so indicated in Part I. Publications in process on December 31, 1953, are designated by an asterisk. Part III is a finding list of states, areas, and subjects. It is based on information derived mostly from the titles of reports and, where titles are of a general nature, from a cursory review of the reports. This list is not a complete index of the information given in Trace Elements and related reports, but is designed to find subjects of major interest. Because of the numerous entries for Colorado and Utah, information has been listed by counties and, where possible, by subject under these states. Other states have county listings only if a county is included in the title of a report; otherwise, areas may be listed separately under the state. Major subjects are listed separately in the index and also where appropriate under states. Analytical methods and subjects related to analytical research are listed under Analytical Methods and Research, but not separately throughout the index. Most mineralogic studies are included under the heading Mineralogy, but are not necessarily listed according to location. Part IV is a finding list of authors. The words “with” and “and” are used to indicate seniority of authorship. For example, a listing of Jones and Brown indicates that Jones is the senior author. A listing of Jones with Brown indicates that Brown is the senior author. In both parts III and IV all Trace Elements reports are listed, as well as other related reports that have not been issued as Trace Elements reports. The following standard abbreviations have been used: TEI, Trace Elements Investigations report; TEM, Trace Elements Memorandum report; P, Professional Paper; B, Bulletin; C, Circular; J, Journal; OF, open file; TIS, Technical Information Service release; NSA, Nuclear Science Abstracts; QM, Quadrangle Map Series; and OM, Oil and Gas map or Mineral Investigations map or report.

Trace Elements Investigations↗
USGS1955

U.S. Geological Survey Trace Elements and related reports through 1954

This report supersedes TEI-400, "U.S. Geological Survey Trace Elements and related reports through 1953." Part I is a numerical list of U.S. Geological Survey Trace Elements Investigations and Memorandum reports. This part lists not only reports (followed by a date) that have been transmitted to the U.S> Atomic Energy Commission, but also reports in preparation (followed by an asterisk) for which tentative titles were available on December 31, 1954. If a report, or portion of a report, has been published, the fact is indicated by the abbreviation of the medium of publication. (See also Part II.) Part II is a reference guide to Trace Elements and related reports that are available to the public (this part supersedes Part I of Bulletin 1019-B). These reports are grouped according to the type of publication or release. If a report, or portion of the report, has been published in more than one form, appropriate cross-references are given to indicate the other forms of publication. Abstracts published in Nuclear Science Abstracts are not included in Part II; however, if the abstract of a Trace Elements report has been published in NSA, the fact is indicated in Part I. Publications in process on December 31, 1954, are designated by an asterisk. Part III is a finding list of states, areas, and subjects and supersedes Part II of Bulletin 1019-B. It is based on information derived mostly from the titles of reports and, where titles are of general nature, from a cursory review of the reports. This list is not a complete index of the information given in Trace Elements and related reports, but is designed to find subjects of major interest, Because of the numerous entries for Colorado and Utah, information has been listed by counties and, where possible, by subject under these states. Other states have county listings only if a county is included in the title of a report; otherwise, area may be listed separately under the state. Major subjects are listed separately in the index and also, where appropriate under states. Analytical methods and subjects related to analytical research are listed under Analytical Methods and Research, but not separately throughout the index. Most mineralogic studies are included under the heading Mineralogy, but are not necessarily listed according to location. Part IV is an author index. The words “with” and “and” are used to indicate seniority of authorship. For example, a listing of Smith and Brown indicated that Smith is the senior author. A listing of Smith with Brown indicates that Brown is the senior author. In both parts III and IV all Trace Elements reports are listed, as well as other related reports that have not been issued as Trace Elements reports. The following abbreviations have been used: TEI, Trace Elements Investigations report; TEM, Trace Elements Memorandum report; OF, open file; TIS, Technical Information Service release; C, Circular; B, Bulletin; P, Professional Paper; MC, Maps and Charts; J, Journal; and NSA, Nuclear Science Abstracts.

Trace Elements Investigations↗
USGS2024

Wildlife stewardship on Tribal lands: Our place is in our soul By Serra J. Hoagland and Steven Albert (Eds.), Baltimore, Maryland: Johns Hopkins University Press. 2023. pp. 432. $59.95 (hardcover). ISBN 978-1-4214-4657-8

Despite thousands of years of land stewardship by Indigenous Peoples, Western ideology and science predominantly influences wildlife management in North America today. Indigenous science and Traditional Ecological Knowledge (TEK) extend beyond the scope of Western science and ecological understanding to include knowledge derived from generations of people living as part of ecosystems (Rinkevich 2008 ). Historically, Western science and TEK have operated separately, resulting in the exclusion of Indigenous Peoples and TEK in wildlife science and management, which has led to significant knowledge gaps in Western science. Today, many practitioners are seeking ways to study and manage wildlife in more inclusive ways that integrate multiple perspectives, including those from Indigenous communities, wildlife managers, researchers, and academics.

Journal of Wildlife Management↗
USGS1993

Petrology and isotopic composition of Quaternary basanites dredged from the Bering Sea continental margin near Navarin Basin

Quaternary basanites were recovered from shallow water depth from the continental margin of the Bering Sea (58°39.0′N, 177°12.9′W) near Navarin Basin. The basanites are highly vesicular flow rock and hyaloclastites similar to other alkalic volcanic rocks erupted repeatedly during the late Cenozoic on islands in the Bering Sea region and in mainland Alaska. K–Ar ages for the basanites indicate at least two episodes of volcanism at about 1.1 and 0.4 Ma. Similar alkalic volcanism occurred sporadically at geographically widely separated centers in the Bering Sea region for at least the past 6 Ma. Chemically, these alkalic lavas are intraplate basalts similar to those erupted from oceanic islands and in some continental settings. Trace-element data indicate these alkalic lavas have been generated by small, but variable, amounts of partial melting of a meta-somatized lherzolite source. The relatively primitive compositions (MgO > 9%), presence of mantle-derived xenoliths in some alkalic lavas, and presence of forsteritic olivine with low CaO and high NiO suggest that magma rose rapidly from greath depth without spending time in large, long-lived magma chambers. Although lavas from different volcanic centers in the Bering Sea region are similar with respect to major elements and many trace-element ratios, isotopic compositions indicate heterogeneities in the source. The Navarin basanites have higher 87 Sr/ 86 Sr and lower 143 Nd/ 144 Nd values than any other lavas so far reported from this region. The 207 Pb/ 204 Pb isotopic ratios indicate involvement of a crustal component, which may have resulted from metasomatism associated with subduction-related magmatic activity during the Early Eocene in this region. Although some volcanic episodes appear to have occurred roughly synchronously at geographically widely separated centers, no large-scale regional extension nor presence of large mantle plumes are indicated. Instead, alkalic volcanism apparently resulted from upwelling and decompressional melting of small isolated mantle diapirs in response to local lithospheric attenuation associated with jostling of blocks during adjustment to regional stresses.

Alaska↗
USGS2012

Studying biodiversity: is a new paradigm really needed?

Authors in this journal have recommended a new approach to the conduct of biodiversity science. This data-driven approach requires the organization of large amounts of ecological data, analysis of these data to discover complex patterns, and subsequent development of hypotheses corresponding to detected patterns. This proposed new approach has been contrasted with more-traditional knowledge-based approaches in which investigators deduce consequences of competing hypotheses to be confronted with actual data, providing a basis for discriminating among the hypotheses. We note that one approach is directed at hypothesis generation, whereas the other is also focused on discriminating among competing hypotheses. Here, we argue for the importance of using existing knowledge to the separate issues of (a) hypothesis selection and generation and (b) hypothesis discrimination and testing. In times of limited conservation funding, the relative efficiency of different approaches to learning should be an important consideration in decisions about how to study biodiversity.

BioScience↗
USGS2004

Mapping saline groundwater beneath the Sea Galilee and its vicinity using time domain electromagnetic (TDEM) geophysical technique

An extensive time domain electromagnetic (TDEM) survey covering the Sea of Galilee with a dense grid of points has been recently carried out. A total of 269 offshore and 33 supplementary onshore TDEM soundings were performed along six N-S and ten W-E profiles and at selected points both offshore and onshore along the whole coastal line. The interpreted resistivities were calibrated with the direct salinity measurements in the Haon-2 borehole and relatively deep (5 m) cores taken from the lake bottom. It was found that resistivities below 1 ohm-m are solely indicative of groundwater salinity exceeding 10,000 mg Cl/l. Such low resistivities (high salinities) were detected at depths greater than 15 m below almost the entire bottom of the lake. At some parts of the lake, particularly in the south, the saline water was detected at shallower depths, sometimes at a few meters below the bottom. Relatively high resistivity (fresh groundwater) was found along the margins of the lake down to roughly 100 m, the maximum exploration depth of the system. The detected sharp lateral contrasts at the lake margin between high and low resistivities coincide with the faults separating the carbonate and clastic units, respectively. The geometry of the fresh/saline groundwater interface below the central part of the lake is very similar to the shape of the lake bottom, probably due to the diffusive salt transport from the bottom sediments to the lake water. The above geophysical observations suggest differentsalt transport mechanisms from the sediments to the central part of the lake (diffusion) and from regional aquifers to the margins of the lake (advection). ?? 2004 Science From Israel/LPPLtd.

Israel Journal of Earth Sciences↗
USGS2018

Shear failure of a granite pin traversing a sawcut fault

Fault heterogeneities such as bumps, bends, and stepovers are commonly observed on natural faults, but are challenging to recreate under controlled laboratory conditions. We study deformation and microseismicity of a 76 mm-diameter Westerly granite cylinder with a sawcut fault with known frictional properties. An idealized asperity is added by emplacing a precision-ground 21 mm-diameter solid granite dowel that crosses the center of the fault at right angles. This intact granite ‘pin’ provides a strength contrast that resists fault slip. Upon loading to 80 MPa in a triaxial machine, we first observed a M -4 slip event that ruptured the sawcut fault, slipped 40 µm, but was halted by the granite pin. With continued loading, the pin failed in a swarm of thousands of M -6 to M -8 events known as acoustic emissions (AEs). Once the pin was fractured to a critical point, it permitted complete rupture events (M -3) on the sawcut fault (stick-slip instabilities). Subsequent slip events were preceded by clusters of foreshock-like AEs, all located on the fault plane, and the spatial extent of the foreshock clusters is consistent with our estimate of a critical nucleation dimension h*. We also identified an aseismic zone on the fault plane surrounding the fractured rock pin. A post-mortem analysis of the sample showed a thick gouge layer where the pin intersected the fault, suggesting that dilatancy of this gouge propped open the fault and prevented microseismic events in its vicinity. Recorded microseismicity separates into three categories: slip on the sawcut fault, fracture of the intact rock pin, and off-fault seismicity associated with pin-related rock joints. We found that pin fracture events were exclusively implosive (anticrack) even though the shear process zone was overall dilatant. This shows how aseismic effects can lead to unexpected seismic manifestations of certain faulting processes.

International Journal of Rock Mechanics and Mining↗
USGS2016

Comments to Middle Miocene closure of the Central American Seaway

In a recent paper proposing an early (mid-Miocene) closure of the Central American Seaway (CAS), Montes et al. 2015 (1) disregard existing paleogeographic data that invalidate Panama as a source for zircons, and inappropriately ignore the evidence for trans-isthmian marine connections until 4-3 Ma. They also fail to cite previous work (2, 3), that had reconstructed the Central American arc already docked with South America by 12 Ma. Montes et al. 2015 (1) (Fig. 1) disregard the Atrato-San Juan sedimentary basin (3), a shallowing Oligocene to Pliocene, Pacific to Caribbean seaway (3, 4, 5). This deep graben (6) is filled with thousands of meters of Pre-Pliocene marine sediments (3, 5, 6) that now occupy a lowland between the Baudo uplift to the west and the Western Cordillera to the east. The Mande Batholith and numerous Eocene and younger volcanic rocks (4), the most proximal source of the zircons, are situated to the east of this seaway and would have shed zircons eastward towards the Cordillera Central. There is no evidence for any rivers crossing the seaway (3, 5), and thus no Panamanian source of zircons. Instead this seaway is evidence of a significant marine connection between the Pacific and Atlantic oceans into the Pliocene. The authors assume that the middle Miocene closure of the CAS effectively creates a continuous land bridge connecting North and South America and separating the Atlantic from the Pacific. They acknowledge, but then discount, marine connections across the Isthmus until 4-3 Ma even though these satisfactorily explain (Coates and Stallard, 2014 (6)) the oceanographic, molecular and Great American Biological Interchange events ignore unexplained by Montes et al. 2015. Only by conspicuously ignoring these events can they imply that the Isthmus was formed at 15-13 Ma. References 1. C. Montes et al., Middle Miocene closure of the Central American Seaway. Science 348, 226-229 (2015). 2. A. G. Coates, R. F. Stallard, How old is the Isthmus of Panama? B Mar Sci 89, 801-813 (2013). 3. H. Duque-Caro, The Choco Block in the northwestern corner of South America: Structural, tectonostratigraphic, and paleogeographic implications. Journal of South American Earth Sciences 3, 71-84 (1990). 4. H. Duque-Caro, Neogene stratigraphy, paleoceanography and paleobiogeography in northwest South America and the evolution of the Panama Seaway. Pal

Science↗
USGS1993

Dissolved inorganic nitrogen composition, transformation, retention, and transport in naturally phosphate-rich and phosphate-poor tropical streams

The composition, transformation, and transport of dissolved inorganic nitrogen (DIN) was compared in waters associated with two lowland streams in Costa Rica. The Salto River is enriched by geothermal-based soluble reactive phosphorus (SRP), which raises the concentration up to 200 μg/L whereas Pantano Creek, an unimpacted tributary, has an SRP concentration <10 μg/L. Ammonium concentration in springs adjacent to the Salto and Pantano was typically greater than channel water (13 of 22 locations) whereas nitrate concentration was less (20 of 22 locations). Ground waters were typically high in ammonium relative to nitrate whereas channel waters were high in nitrate relative to ammonium. Sediment slurry studies indicated nitrification potential in two sediment types, firm clay (3.34 μg N∙cm −3 ∙d −1 ) and uncompacted organic-rich sediment (1.76 μg N∙cm −3 ∙d −1 ). Ammonium and nitrate amendments to each stream separately resulted in nitrate concentrations in excess of that expected after correction for dilution using a conservative tracer. SRP concentration was not affected by DIN amendment to either stream. SRP concentration in the Pantano appeared to be regulated by abiotic sediment exchange reactions whereas DIN composition and concentration were regulated by a combination of biotic and abiotic processes.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS2000

Metalliferous coals of the Westphalian A Joggins Formation, Cumberland basin, Nova Scotia, Canada: Petrology, geochemistry, and palynology

Five coals of Westphalian A (early Middle Pennsylvanian) age were sampled from the Joggins Formation section exposed along Chignecto Bay at Joggins, Nova Scotia. Coal beds along the bay were mined beginning in the early 17th century, yet there have been few detailed published investigation of the coal beds of this classic section. The lowermost coal, the Upper Coal 28 (Upper Fundy), is a high-vitrinite coal with a spore assemblage dominated by arboreous lycopsid spores with tree ferns subdominant. The upper portions of the coal bed have the highest ratio of well-preserved to poorly-preserved telinite of any of the coals investigated. Coal 19 ('clam coal') has 88% total vitrinite but, unlike the Fundy coal bed, the telinite has a poor preservation ratio and half the total vitrinite population comprises gelocollinite and vitrodetrinite. The latter coal bed is directly overlain by a basin-wide limestone bed. The Lower Kimberly coal shows good preservation of vitrinite with relatively abundant telinite among the total vitrinite. The Middle Kimberly coal, which underlies the tetrapod-bearing lycopsid trees found by Lyell and Dawson in 1852, exhibits an upward decrease in arboreous lycopod spores and an upward increase in the tree fern spore Punctatisporites minutus. Telinite preservation increases upwards in the Middle Kimberly but overall is well below the preservation ratio of the Upper Fundy coal bed. The coals all have high sulfur contents, yielding up to 13.7% total sulfur for the lower lithotype of the Upper Fundy coal bed. The Kimberly coals are not only high in total and pyritic sulfur, but also have high concentrations of chalcophile elements. Zinc, ranging up to 15,000 ppm (ash basis), is present as sphalerite in fusain lumens. Arsenic and lead each exceed 6000 ppm (ash basis) in separate lithotypes of the Kimberly coals. Together these data are consistent with elevated pH in planar mires. The source of the elemental enrichment in this presumed continental section is enigmatic. (C) 2000 Elsevier Science B.V. All rights reserved.Five coals of Westphalian A (early Middle Pennsylvanian) age were sampled from the Joggins Formation section exposed along Chigneto Bay at Joggins, Nova Scotia. All the coals were found to have high sulfur contents. Overall, the data obtained are consistent with elevated pH in planar mires.

International Journal of Coal Geology↗
USGS2015

What lies beneath: geophysical mapping of a concealed Precambrian intrusive complex along the Iowa–Minnesota border

Large-amplitude gravity and magnetic highs over northeast Iowa are interpreted to reflect a buried intrusive complex composed of mafic–ultramafic rocks, the northeast Iowa intrusive complex (NEIIC), intruding Yavapai province (1.8–1.72 Ga) rocks. The age of the complex is unproven, although it has been considered to be Keweenawan (∼1.1 Ga). Because only four boreholes reach the complex, which is covered by 200–700 m of Paleozoic sedimentary rocks, geophysical methods are critical to developing a better understanding of the nature and mineral resource potential of the NEIIC. Lithologic and cross-cutting relations interpreted from high-resolution aeromagnetic and airborne gravity gradient data are presented in the form of a preliminary geologic map of the basement Precambrian rocks. Numerous magnetic anomalies are coincident with airborne gravity gradient (AGG) highs, indicating widespread strongly magnetized and dense rocks of likely mafic–ultramafic composition. A Yavapai-age metagabbro unit is interpreted to be part of a layered intrusion with subvertical dip. Another presumed Yavapai unit has low density and weak magnetization, observations consistent with felsic plutons. Northeast-trending, linear magnetic lows are interpreted to reflect reversely magnetized diabase dikes and have properties consistent with Keweenawan rocks. The interpreted dikes are cut in places by normally magnetized mafic–ultramafic rocks, suggesting that the latter represent younger Keweenawan rocks. Distinctive horseshoe-shaped magnetic and AGG highs correspond with a known gabbro, and surround rocks with weaker magnetization and lower density. Here, informally called the Decorah complex, the source body has notable geophysical similarities to Keweenawan alkaline ring complexes, such as the Coldwell and Killala Lake complexes, and Mesoproterozoic anorogenic complexes, such as the Kiglapait, Hettasch, and Voisey’s Bay intrusions in Labrador. Results presented here suggest that much of the NEIIC is composed of such complexes, and broadly speaking, may be a discontinuous group of several intrusive bodies. Most units are cut by suspected northwest-trending faults imaged as magnetic lineaments, and one produces apparent sinistral fault separation of a dike in the eastern part of the survey area. The location, trend, and apparent sinistral sense of motion are consistent with the suspected faults being part of the Belle Plaine fault zone, a complex transform fault zone within the Midcontinent rift system that is here proposed to correspond with a major structural discontinuity.

Iowa, Minnesota↗
USGS1965

A recent occurrence of thermal stratification and low dissolved oxygen in western Lake Erie

Instances of thermal stratification have been detected only occasionally in western Lake Erie during the past 40 years, but when it does occur it is of considerable importance because of associated dissolved oxygen (DO) depletion in the hypolimnion. Data collected in June of 1963 give an indication of the meteorological conditions necessary to produce this thermal stratification. These conditions are: daily wind speed of less than 3.1 m/sec (7 mph); highest wind speed of less than 6.7 m/sec (15 mph); and an average daily temperature of more than 18.5 C for approximately 5 consecutive days. Weather records for Sandusky, Ohio, show these conditions to have occurred on 33 separate occasions between 1953 and 1963. These data suggest stable thermal stratification occurs more frequently than heretofore suspected. The 1963 data also show that in only 5 days of stratification DO in the hypolimnion was reduced to less than 3 ppm, whereas 28 days were required in 1953. This increased rate of DO depletion is probably due to an increase in the oxygen demand of the bottom sediment in recent years.

Ohio Journal of Science↗
USGS1992

Food of the alewife ( Alosa pseudoharengus ) in Lake Ontario before and after the establishment of Bythotrephes cederstroemi

Diets and length&ndash;weight relationships of Lake Ontario alewife ( Alosa pseudoharengus ) in 1972 differed from those in 1988; the large cladoceran Bythotrephes cederstroemi colonized the lake during the mid-1980's. Micro-crustacean zooplankton were the dominant prey of alewife during April&ndash;October in 1972 and 1988. Although Bythotrephes was not found in 1988 net samples, it replaced other zooplankters in the alewife's diet. Typically, tailspines were the only part of Bythotrephes in alewife stomachs; their frequency was high in April&ndash;May, diminished rapidly in summer and was very low by fall. In spring 1988, alewife were in better condition than in spring 1972 and this may have been due to larger fish feeding more heavily on Bythotrephes . Variation in diet among widely separated sampling sites was due to differences in alewife abundance, stability of thermal structure, progress of zooplankton community development and distance to the mouth of the Niagara River (through which Bythotrephes probably enter the lake in summer and fall). In the Great Lakes, inter- and intralake differences in diet clearly exist, and these must be incorporated into models of alewife planktivory to gain an accurate understanding of energy flow between trophic levels.

Canadian Journal of Fisheries and Aquatic Sciences↗
USGS1978

Megalineament in southeastern Alaska marks southwest edge of Coast Range batholithic complex

The Coast Range megalineament is a prominent, nearly continuous topographic and structural feature that extends southeastward about 550 km (330 mi) from its junction with the Chatham Strait – Lynn Canal fault at Point Sherman to Tongass Passage near the mouth of Pearse Canal where it leaves southeastern Alaska. It probably extends still further southeastward into British Columbia along Work Channel and Chatham Sound – Grenville Channel.The megalineament is a zone a few hundred metres to 10 km (6 mi) wide in which closely spaced joints, foliation, compositional layering, and small faults define the megalineament trend. The zone usually coincides with topographic depressions apparently caused by selective fluvial and glacial erosion of the less resistant rocks of the zone.Studies in the Juneau, Endicott Arm, and Behm Canal areas indicate that the megalineament (1) is locally the site of lateral and (or) vertical separations of no greater than several kilometres; (2) does not mark a major structural or metamorphic discontinuity in the near-surface rocks; (3) may be located near a pre-metamorphic and pre-intrusive discontinuity; (4) is consistently associated with and parallel to steep gradients in both the gravity and aeromagnetic fields; and (5) probably is the surface expression of the western contact, at depth, of the intrusive rocks and gneisses of the Coast Range batholithic complex with the schists to the southwest.

Alaska↗
USGS1992

Uranium-series isochron dating at El Castillo Cave (Cantabria, Spain): The "Acheulean"/"Mousterian" question

A massive flowstone layer, Level 23, near the base of the stratigraphic sequence in El Castillo Cave (Cantabria, Spain), is dated by the uranium-series isochron method to 89+11/−10 ka bp. The flowstone separates cultural layers traditionally labelled “Mousterian” (above) and “Acheulean” (below). The date reported here, in association with other recent age determinations for “Mousterian” and “Acheulean” artifact assemblages in Western Europe, calls into question the temporal significance of these archaeological designations. In addition, it further underlies the importance of the Castillo cultural sequence and allows tentative discussion of changing rates of sedimentation in the vestibule of the cave, where some 18 m of cultural and geological deposits were laid down during the course of the Upper Pleistocene.

Journal of Archaeological Science↗