nils-herrmann/clean_scirepeval huggingface dataset:
Mid-Carboniferous deglaciation of the Protoprecordillera, Argentina recorded in the Agua de Jagüel palaeovalley

The Agua de Jaguel Formation near Uspallata, Mendoza Province, Argentina, was deposited within a palaeovalley along the southeastern margin of the Calingasta–Uspallata Basin adjacent to the Protoprecordillera. The basal glacigenic sequence of the formation was deposited in the Serpukhovian–Early Bashkirian, near the beginning of the late Palaeozoic ice age. The sequence is composed of diamictite, conglomerate, sandstone, and mudrock and records four depositional stages within a palaeofjord: 1. morainal bank deposition by a wet-based tidewater glacier, 2. glacial retreat succession where ice retreated up the fjord out of the immediate area, allowing iceberg deposition of dropstones and dump deposits, 3. continued glacial retreat with ice receding onto land, allowing a shoreface to develop within the palaeovalley, and 4. transgression across the shoreface and resumption of iceberg deposition. The thickness and facies of this succession are similar to deposits within modern Alaskan fjords housing temperate tidewater glaciers. Comparison of the Agua de Jaguel Formation with Alaskan fjords indicates that sequence stratigraphy used for low latitude deposits must be applied with caution, as glacimarine ice retreat within a fjord produces strata surfaces that are easily misidentified as flooding surfaces resulting from changes in water depth. Likewise, the transgression during stage 4 is significant as it indicates a rise in sea level that occurred during glaciation of the Protoprecordillera, thus suggesting that the transgression between stages 3 and 4 was not driven by input of glacial meltwater. Additionally, the sediment geochemistry suggests that the bottom waters of the palaeovalley were anoxic, which may help explain the absence of bioturbation in the sequence as well as in other ancient glacimarine palaeovalleys. The deglaciation succession and transgression are also recorded in the nearby Hoyada Verde and Tramojo Formations, so it is proposed that all three formations record one glacial event in the Protoprecordillera. Overlying fluvial and shallow marine strata in the Agua de Jaguel, Hoyada Verde, and Tramojo Formations show no indication of continued glaciation in the Protoprecordillera following stage 4 and equivalent strata. The deglaciation succession of the Agua de Jaguel Formation affirms the emerging concept that the late Palaeozoic ice age was characterized by alpine glaciers, ice caps, and small ice sheets that were not massive enough to have driven eustatic fluctuations of 100 m+ as previously understood, and that ice never covered westernmost Gondwana during later LPIA events.

Field of study: Geology
Cenozoic palaeogeographic development of northern Tunisia, with special reference to the stratigraphic record in the miocene trough

Cenozoic deposits are present in five northeast-trending provinces of northern Tunisia, from northwest to southeast: the Numidian belt, the western (Brjaoua) and eastern (Bou Sefra) parts of the Miocene Trough, the Fortuna Basin, and the Eastern Platform. The critical Bou Sefra sequence is an essentially complete fossiliferous Miocene succession. These Cenozoic deposits record six episodes: (1) Widespread Paleocene and Eocene Tethyan transgression flooded the entire region. (2) During Oligocene time the inner part of the northwestern cratonic margin was uplifted and eroded while a pelagic facies filled a northeast-trending precursor of the Fortuna Basin. At the same time a shallow marine facies prevailed to the east, south, and west. (3) Increased Early Miocene deformation in the Fortuna Basin area led to accumulation of thick, conglomeratic deltaic to alluvial sandstone which graded laterally into shallow marine deposits on the Eastern Platform. Neritic sediments also accumulated along much of the Miocene Trough to the west, and later spread eastward over the Fortuna Formation. Farther northwest a thick succession of sandy Numidian turbidites was deposited along the outer continental margin of north Africa. (4) In Middle Miocene time Numidian nappes were emplaced in the northwest while deformation and local uplift within the Miocene Trough was accompanied first by marine marl and mud and then by accumulation of a muddy flyschoid facies that graded into neritic to paralic deposits farther east. (5) During late Miocene time uplift and erosion prevailed in the far northwest while a shallow marine facies in the Miocene Trough was succeeded by evaporite-bearing neritic to paralic deposits before the end of the Miocene Epoch. Neritic to paralic facies dominated the eastern part of the Fortuna Basin area and the Eastern Platform throughout this episode. (6) Intense deformation at the end of Miocene time produced uplifts in the northwest and along the Tunisian Atlas flanked by coarse-grained nonmarine Pliocene deposits, as well as local subsidence and marine basin fill in the Bizerte area in the northeast and on Cap Bon Peninsula to the east.

Field of study: Geology
Introduction to this special section: Borehole geophysics and sonic logging

Sonic logs are most frequently used to tie surface and borehole seismic amplitude measurements to P- and S-wave velocities encountered along wellbore trajectories. Other common uses of sonic logs include the estimation of dynamic elastic properties for geomechanical analysis, such as wellbore stability studies and the design and planning of hydrofracturing operations. Modern sonic logs are acquired with multiple transmitters and an array of closely spaced receivers (anywhere between eight and 13 receivers) in the form of time waveforms. Sonic transmitters can come in the form of monopole, dipole, and quadrupole actuators. By design, sonic transmitters are immersed in a fluid — the borehole mud — whereby formation shear waves can be detected and quantified only by the elastic coupling that exists between wave motion taking place in the borehole fluid and in the surrounding rock formations. Such an elastic coupling gives rise to markedly frequency-dispersive behavior of the detected waves that presents some technical challenges when one interprets their speeds.

Field of study: Geology, Physics
Field Water Drainage under Traditional and Improved Irrigation Schedules for Corn in Central Spain

Traditional irrigation schedules used by farmers in central Spain may result in overirrigation and deep percolation. The objective of this research was to test whether an improved irrigation schedule based on restoring field capacity in the 0- to 0.5-m soil layer could save irrigation water and reduce drainage (D) without impairing grain yield. A 4-yr field experiment was conducted near Madrid, Spain. A neutron probe and tensiometers were used to measure water in storage and flux in a sandy-loam soil (Typic Xerofluvent) with a corn (Zea mays L.)-wheat (Triticum aestivum L.)-corn-oat (Avena sativa L.) crop rotation common in the area. Crop water consumption and D were estimated with the zero flux plane-water balance equation. The improved irrigation schedule, only applied to the two corn crops, saved 170 mm of irrigation water, or 15% of the irrigation water used for traditionally irrigated plots. Drainage during the experiment was reduced from 235 mm in traditional to 11 9 mm in improved treatment. The cumulative grain yield for subsequent crops was unaffected by the irrigation treatments (31 230 ± 3900 vs. 30 770 ± 3430 kg ha -1 ). Grouped across the 4-yr period, variation of evapotranspiration (ET) between individually instrumented sites (4%) was lower than the variation of D (30%). When daily ET and D estimates were grouped for cropping and intercultivation periods and compared with changes in water storage added to irrigation and rainfall, the mass balance principle was satisfied. Experienced corn farmers may apply this improved schedule by assessing soil depth of wetting.

Field of study: Agricultural and Food sciences
Principes et methodes d'une paleoichthyologie bathymetrique

Although devoted to the study of mobile animals, palaeoichthyology is considered a relatively precise tool for determining the depth of deposition of ancient sediments. According to the composition and the geological age of the faunas to be analyzed, two palaeoautoecological methods may be used. The comparative bathymetrical method uses the bathymetrical distribution of Recent Fishes most closely related to the fossils studied. When the latter differ too greatly from Recent fishes, the use of morpho-functional analysis permits interpretation of their palaeoenvironment. Some examples are discussed.

Field of study: Geology
Challenges in groundwater resource management in coastal aquifers of East Africa: Investigations and lessons learnt in the Comoros Islands, Kenya and Tanzania

Coastal areas of Kenya (Kilifi County), Tanzania (Kilwa district) and Comoros (Ngazidja island), East Africa. Study focus Research aimed to understand the physical and societal drivers of groundwater accessibility and identify critical aspects of groundwater access and knowledge gaps that require further monitoring and research. Interdisciplinary societal, environmental and hydrogeological investigations were consistently undertaken in the three areas considered as exemplars of the diversity of the coastal fringes of the wider region. This paper focuses on the hydrogeological outcomes of the research, framed within the principal socio-environmental issues identified. New hydrological insights Results confirm the fundamental importance of coastal groundwater resources for the development of the region and the urgent need to match groundwater development with demographic and economic growth. Hydrogeological knowledge is fragmented, groundwater lacks a long-term monitoring infrastructure and information transfer from stakeholders to users is limited. Current trends in demography, climate, sea-level and land-use are further threatening freshwater availability. Despite possessing high-productivity aquifers, water quality from wells and boreholes is generally impacted by saltwater intrusion. Shallow large-diameter wells, following the traditional model of these areas, consistently prove to be less saline and more durable than deeper small-diameter boreholes. However, promoting the use of large numbers of shallow wells poses a significant challenge for governance, requiring coherent management of the resource at local and national scales and the engagement of local communities.

Field of study: Agricultural and Food sciences, Geography
Discussion on the Paper by A. Ziolkowski

The paper by A. Ziolkowski which appeared in the February issue of Geophysics has generated a great deal of interest. For our readers’ convenience, we are reprinting here two letters that appeared in The Leading Edge (July 1991 TLE, p. 8), followed by three discussions on the paper and a reply to each by the author. Every once in a great while, a paper appears in Geophysics which is more significant than first meets the eye and mind. These papers, like too many others, are barely scanned and forgotten or brushed aside, or even criticized for incidental reasons (disagrees with our own ideas, isn’t written in an acceptable “tone,” etc.). I think Ziolkowski’s paper in the February 1991 issue (Why don’t we measure seismic signatures?) is possibly one of these.

Field of study: Geology
Geodynamics and petroleum formation in the sedimentary basins of Southeast Asia

An interesting overview of the region is presented, emphasizing some aspects not usually considered by Western geologists as closely involved in petroleum generation. Southeast Asia corresponds in the geological sense to the Indo-Pacific region, which has a unique variety of structures, the formation of which was determined by processes in the boundary zone between the Eurasian and Australian cratons and the pacific and Indian thalassogens. The most recent published sources of geological and geophysical information are reviewed to provide a model for the formation of the sedimentary basins in craton-thalassogen boundary zones. 15 references, 2 figures.

Field of study: Geology
Application of Large-scale Satellite Image in Land Use Dynamic Monitoring of Xuzhou Urban Area

With Xuzhou urban area as monitoring range,the current status of land use in Xuzhou city was interpreted and investigated by using false color composite image.Compared with historical data,dynamic change status of land utilization in this city was monitored.And the feasibility of this method,the changes of land type in this city and the monitoring results were analyzed.

Field of study: Geography
Surface microtextures of quartz grains from the central coast of Tamil Nadu

Quartz grain surface micro textures of 12 samples collected from the beach were examined under scanning electron microscopy to understand the role of coastal processes on their transportation and deposition. The study area has been divided into three sectors on the basis of drainage, geomorphology and nature of the beach and shelf topography. Surface textures of the northern sector display an array of mechanical features like conchoidal fracture, V marks and impact pits, indicating the dominance of mechanical processes. However, silica precipitation in the form of globules indicates an added influence of chemical processes in the Northern sector. The presence of chemical features in northern sector, where energy level is high, corroborates the addition of quartz grains from paleo-sediments, from the nearby Tertiary and Cretaceous formations. Central sector quartz grains display the signatures of chemical and mechanical processes. The presence of step like furrows in southern sector is an indicator of fluvial low energy conditions, and supplements the role of littoral currents in depositing the quartz grains along the coastal region.

Field of study: Geology
Mapping raster imagery to the Interrupted Goode Homolosine projection

Because of the increasing emphasis on global monitoring, processing remotely-sensed raster image data onto global map projections has become an important issue. One class of map projections, interrupted equal-area projections, is especially useful for this purpose. The use of the Interrupted Goode Homolosine map projection for the Global Land Advanced Very High Resolution Radiometer (AVHRR) 1 km project and the AVHRR Pathfinder project has produced a map that is both attractive to the viewer and useful for data analysis. This interrupted, composite, equal-area map projection uses the Sinusoidal projection for low latitudes and the Mollweide projection for high latitudes and is broken into 12 regions, each with its own central meridian. This combination of projections helps to preserve the shape of the land masses and results in a map that has less distortion than an uninterrupted global map. The use of the interrupted projection also simplifies the processing and management of larger data sets, b...

Field of study: Geography
An investigation of breakage behaviour of single sand particles using a high-speed microscope camera

Much research has focused on the micro-mechanics of sand particles. The single particle uniaxial compression test is a common way to study breakage behaviour. However, there is still little agreement on particle breakage criteria and the mechanisms of breakage remain uncertain, partly because of the often rapid brittle failure of sand particles. In this study, a series of single particle uniaxial compression tests on different kinds of sand particles were carried out, using a high-speed microscope camera to capture the processes of breakage. This enabled a maximum of 2000 frames to be obtained per second to identify clearly the failure processes and crack propagation. Four failure modes have been proposed based on the rapidity of failure and the size and number of particle fragments created during the breakage: splitting, explosive, explosive–splitting and chipping. The relationship between the particle strength and the breakage mode has then been explored, investigating also whether immersion would affec...

Field of study: Materials science
Changes in Seawater 87 Sr/ 86 Sr Curve during Early Miocene to Early Late Miocene: Implications of ODP Site 758A Record

A seawater 87 Sr/ 86 Sr record is generated for early Miocene to early late Miocene based on measurements of 114 samples of cleaned planktonic foraminifera from Ocean Drilling Program site 758 (Hole 758A) in the eastern Indian Ocean. Age model for this Site is based on nannofossil events and interpolated numerical ages are compared with Sr Isotopically-Derived ages, There is a fairly good agreement between the two stratigraphic tools (<±1.5 Ma). 87 Sr/ 86 Sr ratio during ∼23.7 Ma to ∼8.1 Ma increased from 0.70828 to 0.70895, with variations in the rate of 87 Sr/ 86 Sr increase. Seventh-Order polynomial fit curve shows the 87 Sr/ 86 Sr increase rates of 44 ×10 -6 m .y. -1 for -23.7 to ∼19.2 Ma, 41 × 10 -6 m.y. -1 for -18.2 to - 10.8 Ma, and 25 × 10 -6 m.y. -1 for ∼10.8 to ∼8.1 Ma. These rates are broadly consistent with the growth rates of 87 Sr/ 86 Sr reported from other DSDP and ODP sites with some minor differences. A composite Sr isotope curve constructed for the 24-8 Ma is broken into three linear segments with a different linear regression equation. The overall rate of 87 Sr/ 86 Sr increase for ∼24-8 Ma at site 758A (40 x 10 -6 m.y. -1 ) is in agreement with the rate of 87 Sr/ 86 increase of the composite curve (42 x 10 -6 m.y. -1 ).

Field of study: Geology
Study of Multipurpose Integration of Urban and Rural Cadastral Management Information System Design Based on GIS

Multipurpose integration of urban and rural cadastral management information system(M-ICMIS) was pointed out in this article.M-ICMIS was based on the basic geographic information database.Detailedly,the system design project including system design object,data base structure,system architecture of M-ICMIS was explored on the basis of urban and rural areas integrating land management operation flow design.Finally,the developing trend of M-ICMIS by basic geographic information data was discussed.

Field of study: Engineering, Geography
Terrestrial sedimentary responses to astronomically forced climate changes during the Early Paleogene in the Bohai Bay Basin, eastern China

High-resolution measurements of magnetic susceptibility (MS) (8029 samples) and X-ray fluorescence (XRF) elements (4367 samples) were performed on the ~403-m-thick Shahejie Formation in the Bohai Bay Basin, eastern China. The power spectral and fast Fourier transform (FFT) spectrogram analyses of the MS series reveal that the wavelength ratios of the stratigraphic cycles are ~20:5:2:1, which is consistent with the period ratios of astronomical cycles (long eccentricity, short eccentricity, obliquity, and precession). A floating-point time scale (FPTS) was developed by tuning the magnetostratigraphic susceptibility (MSS) zonation to the standard reference zonation (SRZ) established by using the same interval of semi-long eccentricity (200 kyr). The depositional durations of the lower third member (Es3l) and upper fourth member (Es4u) of the Eocene Shahejie Formation were estimated to be 2.03 ± 0.2 Myr and 1.97 ± 0.2 Myr, respectively. The sedimentary accumulation rates (SARs) during different stages were calculated based on the FPTS; the SAR of the deep to semi-deep lacustrine deposits was generally lower than 10 cm/kyr, while that of the shallow lacustrine deposits was higher than 10 cm/kyr. The significant ~1.2-Myr cycles, which were related to the planetary secular frequencies s4-s3, were coincident with the periodic climatic variation in the study area, while the ~0.84-Myr cycles may have been long-period astronomical cycles unique to the Dongying Sag. Furthermore, both of these cycles may have controlled the enrichment of the hydrocarbon source rocks in eastern China.

Field of study: Environmental science, Geology
Foraminiferal assemblages from ice-proximal paleo-settings in the Whales Deep Basin, eastern Ross Sea, Antarctica

Reconstructions of Ross Sea paleoenvironments based on foraminifera are hindered by the dearth of actualistic data, especially from below the Ross Ice Shelf. To fill this gap, we used a recently developed well-resolved deglaciation record from the Whales Deep Basin of the eastern Ross Sea to understand the ecological affinities of different foraminiferal assemblages. During open-water conditions similar to the present, two benthic foraminiferal communities are strongly dominated by agglutinated species. However, in the underlying sediments that represent sub-ice-shelf and grounding-zone proximal settings on the outer continental shelf, we identified five different assemblages of calcareous foraminifera. By Antarctic margin standards, these calcareous assemblages are periodically truly abundant. Along with assemblages dominated by benthic calcareous species that are well known from many Antarctic settings, i.e. , Globocassidulina biora , Trifarina earlandi , and Astrononion echolsi , two important assemblages are dominated by a heretofore undescribed pustulose morphotype of G. biora and poorly known spinose morphotype of T. earlandi . Based on our correlations to the deglacial record, these two assemblages live near the grounding line or in environments with especially intense bottom water currents. As grounded and floating ice retreated south to the middle continental shelf, these later sub-ice-shelf and grounding-zone proximal settings were largely devoid of calcareous foraminifera and instead were inhabited by agglutinated taxa. This improved understanding of foraminiferal assemblage distributions from a variety of environments within the eastern Ross Sea may contribute to better use of foraminiferal data to investigate the evolution of environmental changes in grounding-line proximal environments.

Field of study: Geology
Gelation and Fusion Characteristics of PVC Resins in Plastisol by Determination of Their Viscoelasticity

A method of characterizing gelation and fusion behavior by viscoelastic measurements has been developed previously1. The present work is an application of this method for finger-printing the gelation and fusion profiles of commercial dispersion resins. The Rheometrics Mechanical Spectrometer was used in the dynamic oscillatory mode at 1 Hz with a programmed increase of temperature. The elastic modulus, G′, loss modulus, G″ and the complex viscosity |η*| were recorded as functions of temperature. Two temperature profiles were used: one was 20°C/min. to simulate a process, i.e., a heating rate in an oven, and the other was 5°C/min., a slower heating for a better characterization of gelation behavior.

Field of study: Materials science
Introduction of silica into thermo-responsive poly(N-isopropyl acrylamide) hydrogels : A novel approach to improve response rates

The response rates of novel thermo-responsive poly( N -isopropyl acrylamide) (PNIPAM) hybrid hydrogels are compared to those of conventional chemically crosslinked PNIPAM hydrogels. The former materials were obtained by applying the sol–gel technology, in which the inorganic silica particles act as physical crosslinks for the organic polymer chains, leading to a semi-interpenetrating polymer network structure. In situ modulated temperature DSC shows that the introduction of hydrophilic silica improves the thermal response rate of the hybrid hydrogels to a great extent as compared to aqueous PNIPAM solutions and conventional PNIPAM hydrogels. Ex situ gravimetrical measurements also illustrate that the shrinking/swelling rate of the hybrid hydrogels is largely improved. It is assumed that the uniform distribution of the SiO 2 units, as demonstrated by cryo-field emission scanning electron microscopy, causes the silica to act as nano-sized water reservoirs, which reduce the characteristic diffusion length of water in the PNIPAM matrix so that it can be transported faster within the hybrid PNIPAM nano-composite.

Field of study: Materials science