Miracle-dz/UniFAR-FTUs huggingface dataset:
U-series Constraints on Intraplate Basaltic Magmatism

Intraplate magmatism represents approximately one tenth of the flux of magma to the Earth’s surface (Sleep 1990). This type of magmatism has received considerable attention from petrologists and geochemists as it generally exhibits a wider range of chemical compositions than the more uniform mid-ocean ridge basalts. Hence, it is rather paradoxical that our understanding of intraplate magmatism is rather poor. In this chapter, we review the insights that have been gained from using U-series measurements (combined with other chemical and isotopic constraints) to better understand the sources and processes related to intraplate volcanism. Several unique constraints can be obtained from measurement of U-series disequilibria in basalts. First, U-series fractionation can tell us about the residual phases present during melting as small differences in partitioning behavior between the nuclides will induce distinct signatures. Second, as has been shown by the earlier work of Allegre and Condomines (1982), Th isotope ratios can be used to infer the Th/U ratio of the mantle source providing another useful probe for mapping mantle heterogeneities. Lastly, as detailed below, the time-dependence of U-series fractionation during melting and melt migration can place constraints on several rate-dependent parameters such as the melt production rate, and melt velocities. An important feature of hotspot magmatism is that in many cases, the timing of hotspot activity seems to be decoupled from the motion of the lithospheric plate. This observation, which has been the basis for proposing the existence of mantle plumes, suggests that magmas erupted at hotspots should reveal something about the nature of the deeper mantle. Understanding the processes of hotspot magmatism should also tell us about the nature of convective motion responsible for hotspots. In the following section, we first review some of the outstanding issues that need to be resolved to better understand intraplate magmatism. We then …
Globalization, Frontier Masculinities and Violence: Booze, Blokes and Brawls

Over the last two decades, two new trajectories have taken hold in criminology-the study of masculinity and crime, after a century of neglect, and the geography of crime. This article brings both those fields together to analyse the impact of globalization in the resources sector on frontier cultures of violence. This paper approaches this issue through a case study of frontier masculinities and violence in communities at the forefront of generating resource extraction for global economies. This paper argues that the high rates of violence among men living in work camps in these socio-spatial contexts cannot simply be understood as individualized expressions of psycho-pathological deficit or social disorganization. Explanations for these patterns of violence must also consider a number of key subterranean convergences between globalizing processes and the social dynamics of male-on-male violence in such settings.
Computed tomography for rock-property determination and fluid-flow visualization

This paper discusses the development and application of X-ray computed tomography (CT) for the determination of rock properties and the study of miscible displacements in laboratory cores. Saturation (relative permeability) and porosity measurements by CT scanning are described, and the results are compared to those of conventional methods. Results of corefloods with miscible fluids show the influence of rock heterogeneities (bedding planes) and mobility ratio on volumetric sweepout. The corefloods also illustrate a new display technique that combines a series of two-dimensional (2D) CT slices into three-dimensional (3D) perspective views.
Distribution of seismicity across strike‐slip faults in California

[1] The distribution of seismicity about strike-slip faults provides measurements of fault roughness and damage zone width. In California, seismicity decays with distance from strike-slip faults according to a power law ∼(1 + x2/d2)−γ/2. This scaling relation holds out to a fault-normal distance x of 3–6 km and is compatible with a “rough fault loading” model in which the inner scale d measures the half width of a volumetric damage zone and the roll-off rate γ is governed by stress variations due to fault roughness. According to Dieterich and Smith's 2-D simulations, γ approximates the fractal dimension of along-strike roughness. Near-fault seismicity is more localized on faults in northern California (NoCal, d = 60 ± 20 m, γ = 1.65 ± .05) than in southern California (SoCal, d = 220 ± 40 m, γ = 1.16 ± .05). The Parkfield region has a damage zone half width (d = 120 ± 30 m) consistent with the SAFOD drilling estimate; its high roll-off rate (γ = 2.30 ± .25) indicates a relatively flat roughness spectrum: ∼k−1 versus k−2 for NoCal, k−3 for SoCal. Our damage zone widths (the first direct estimates averaged over the seismogenic layer) can be interpreted in terms of an across-strike “fault core multiplicity” that is ∼1 in NoCal, ∼2 at Parkfield, and ∼3 in SoCal. The localization of seismicity near individual faults correlates with cumulative offset, seismic productivity, and aseismic slip, consistent with a model in which faults originate as branched networks with broad, multicore damage zones and evolve toward more localized, lineated features with low fault core multiplicity, thinner damage zones, and less seismic coupling. Our results suggest how earthquake triggering statistics might be modified by the presence of faults.
Improvement of fire danger modelling with geographically weighted logistic model

Global models dominate historical documents on fire danger modelling. However, local variations may exist in the relationships between fire presence and fire-influencing factors. In this study, 50 fire danger models (10 global logistic models and 40 geographically weighted logistic models, i.e. local models), were developed to model daily fire danger in Heilongjiang province in north-east China and cross-validation was performed to evaluate the predictive performance of the various developed models. In modelling, multi-temporal spatial sampling and repeated random sub-sampling were applied to obtain 10 groups of training sub-samples and inner testing sub-samples. For each of the 10 groups of training sub-samples, principal component analysis, in which muticollinearity among variables can be removed, was used to create nine principal components that were then employed as covariates to develop one global logistic model and four geographically weighted logistic models. Compared to global models, all local models showed better model fitting, less spatial autocorrelation of residuals and more desirable modelling of fire presence. In particular, not only was local spatial variation in fire–environment relationships accounted for in the adaptive Gaussian geographically weighted logistic models, but spatial autocorrelation of residuals was significantly reduced to acceptable levels, indicating strong inferential performance.
Geosynclinal Compositions and the New Global Tectonics

ABSTRACT The lithological composition of several geosynclinal sequences estimated from published measured sections in the Appalachian and Cordilleran belts shows that sedimentary rock type is not a diagnostic attribute of geosynclinal assemblages. However, though no sedimentary rock types are excluded from geosynclinal assemblages, some are generally rare (evaporite), others are particularly common in either the miogeosyncline (carbonate) or eugeosyncline (graywacke), and still others are common throughout (shale). The chemical composition of individual sequences, estimated using analyses of specific stratigraphic units and average compositions for major sedimentary and volcanic rock types reveals chemical contrasts between miogeosynclinal and eugeosynclinal assemblages, and between ancient geosynclinal assemblages and the sedimentary successions which have accumulated in the deep ocean basins and along the present-day continental margins. Miogeosynclinal and eugeosynclinal assemblages differ chemically because of the respective predominance of carbonate and volcanic rocks; both contain chemically similar, highly siliceous clastics. If miogeosynclines and eugeosynclines are the respective ancient analogues of present-day continental shelf and rise areas, their contrasting compositions may reflect long-term secular changes in the mode and locus of sedimentation as a result of organic evolution and changes in the relief, volume, and location of continental blocks, ocean basins, and plate margins during and since the Paleozoic.
Seismic velocity studies of a gas hydrate bottom-simulating reflector on the northern Cascadia continental margin: Amplitude modeling and full waveform inversion

On the northern Cascadia subduction margin, the multichannel seismic amplitude-versus-offset (AVO) behavior of a bottom-simulating reflector (BSR) suggests a P wave velocity change from high-velocity hydrate-bearing sediment to lower velocity sediment containing a small amount of free gas. The observed nonlinear AVO behavior, constant or slightly decreasing amplitudes at near-to-mid offsets and a large-amplitude increase at far offsets, can be reproduced in the models if an S wave velocity enhancement is assumed as expected from hydrate cementation. The AVO behavior of the hydrate BSR is found not to be as useful as was earlier thought for determining the amount of free gas below the BSR. This is because Poisson's ratio change below the BSR due to gas is likely very small in high-porosity unconsolidated sediments. The uncertainty in the models is large, as there is no reliable S wave velocity information for the sediments containing hydrate or gas. AVO modeling alone is not sufficient to distinguish different velocity models across the BSR. Our interpretation of the BSR amplitude behavior is that a P wave velocity increase above the BSR is the main cause of the BSR reflection amplitude increase at large incidence angles. Caution must be taken in applying AVO analysis, as little is known about S wave velocities. However, subtle differences in BSR amplitude behavior and reflection waveform can provide constraints through very careful full waveform inversion. A well-defined reference velocity-depth profile is also required to represent water-saturated sediment unaffected by either hydrate or free gas. Using full waveform velocity inversion, a high-resolution velocity model for the hydrate BSR has been derived. The best fit model for the seismic data near the Ocean Drilling Program (ODP) sites 889/890 consists of a high-velocity zone above the BSR and a thin low-velocity layer below, in agreement with the ODP downhole velocity data.
Aggregation and Sedimentation of Iron, Phosphorus and Organic Carbon in Experimental Mixtures of Freshwater and Estuarine Water

Abstract The importance of salinity and suspended minerogenic particles on the aggregation and sedimentation processes of iron, phosphorus and organic carbon was studied in experimental procedures with waters from the River Ore and from the Ore Estuary, northern Sweden. The aggregation of dissolved iron and phosphorus reached at least 40–90% and 30–60%, respectively, at salinities between 4 and 6. Only a few percent, less than 10%, of the dissolved organic carbon aggregated. Rapid and nearly complete sedimentation of iron and phosphorus aggregates was found at high salinities (4–5) and in the presence of clay particles. Mineral particles increase sedimentation by sorption of formed iron and phosphorus aggregates. Only a small amount of the organic carbon sedimented.
Polar patches: Auroral zone precipitation effects

[1] We look at patches observed by digital ionosondes in the northern polar cap. These observations show that patches have the following properties. (1) Patches are relatively large, typically ∼500 km in the sunward-antisunward direction and ∼1000 km in the dawn-dusk direction. (2) When the IMF Bz has abnormally large positive-negative swings the patches show correlation with the IMF Bz swings. (3) For typical days the patches show no average correlation with IMF By and only weak correlation with negative IMF Bz. (4) Patches are slightly weaker in summer. The typical patch max-to-min Ne variation in winter is ∼2 × 1011 el/m3 and in summer it is ∼1.5 × 1011 el/m3. (5) There is restructuring of patches, particularly the small-scale structures, as the patches convect across the polar cap. (6) Patches are formed prior to entering the polar cap and their properties stay about the same thereafter. We explain the patch generation and most of these properties by low-energy precipitation into the returning flow from the nightside to the dayside around the dawn convection cell.
Strain-rate effects in pressuremeter testing using a cuboidal shear device: experiments and modeling

The objective of the present research was to study the effect of rate of probe expansion in pressuremeter testing for cohesive soil. Emphasis in this paper was given to quantifying and modeling the effect of strain rate on the undrained shear strength. The strain path followed by an element of clay adjacent to the expanding probe was simulated using an automated flexible boundary cuboidal shear device (CSD) typically up to a magnitude of strain level of 10%. Two types of soil (kaolin, kaolin-silica mix) were used consistently for all the testing. Repeatable cubical cohesive specimens were obtained from a high water content slurry consolidation technique. K0 consolidation was performed by using a constant vertical stress - zero lateral strain boundary condition using a closed-loop pneumatic system. A series of strain-controlled tests with increasing strain rates from 0.01 to 5%/min was performed under undrained conditions. The effects of increase of strain rate on shear stress - strain behavior and undrain.
Effect of Different Levels of Applications of Illite on the Growth of Red Pepper in Soil

This study was performed to examine the effect of the clay mineral illite on the improvement of soil and plant growth. Red pepper (Capsicum annuum L.) was used as a test vegetable crop. The experiment was performed during six weeks in the plantation of the Chungbuk National University. Its seedlings were cultivated in the soil normally used for horticultural purpose. Among the seedlings germinated the healthy and regular size of seed were selected and cultivated in the plantation. They were treated with two forms of illite, particulate (PA) and powder (PW), at the following application rates: standard application[P1 (PA1, PW1), soil: illite = 1:20 (w/w)] and two times [P2 (PA2, PW2), 1:10 (w/w)] of standard application. Untreatment (P0) was used as a control soil. At six weeks of cultivation, their growth lengths were correspondingly increased as the application rate was increased ranging from P0, P1, and P2. Their growth length was a little greater with the application of powder illite (PW) than with the particulate illite (PA). Based on the plant analysis of root, leaf, and stem of red pepper, the uptake amounts of K, Ca, and Mg, were correspondingly increased, as the application rate was increased ranging from P0, P1, and P2 respectively. At the same application rate, their amounts taken up in the respective parts were higher with the application of PW illite than on the PA one. Especially the amounts of Ca and Mg were higher in the stem and leaf than root. Consequently, it appears that the illite treatment, especially, PW form of illite, enhance the growth of red pepper in the plantation during the six weeks of experiment.
Predicting the Probability of Elevated Nitrate Concentrations in the Puget Sound Basin: Implications for Aquifer Susceptibility and Vulnerability

The occurrence and distribution of elevated nitrate concentrations (≥ 3 mg/l) in ground water in the Puget Sound Basin, Washington, were determined by examining existing data from more than 3000 wells. Models that estimate the probability that a well has an elevated nitrate concentration were constructed by relating the occurrence of elevated nitrate concentrations to both natural and anthropogenic variables using logistic regression. The variables that best explain the occurrence of elevated nitrate concentrations were well depth, surficial geology, and the percentage of urban and agricultural land within a radius of 3.2 kilometers of the well. From these relations, logistic regression models were developed to assess aquifer susceptibility (relative ease with which contaminants will reach aquifer) and ground‐water vulnerability (relative ease with which contaminants will reach aquifer for a given set of land‐use practices). Both models performed well at predicting the probability of elevated nitrate concentrations in an independent data set. This approach to assessing aquifer susceptibility and ground‐water vulnerability has the advantages of having both model variables and coefficient values determined on the basis of existing water quality information and does not depend on the assignment of variables and weighting factors based on qualitative criteria.
QUATERNARY GEOLOGY OF THE BENGAL BASIN, EAST PAKISTAN AND INDIA

Reconnaissance of the Bengal provinces of East Pakistan and India indicates that structural activity, primarily faulting, has significantly influenced Quaternary geology. Two areas of Pleistocene terrace border the Bengal basin on the east and west and flank Tertiary and older hills of India. Two large inliers of Pleistocene sediments within the basin are surrounded by Recent flood-plain deposits of the Ganges and Brahmaputra rivers and their combined deltaic plain. Block faulting and echelon faulting have so disturbed the topography of the Pleistocene terrace that the reconnaissance was insufficient to permit determination of whether multiple terraces are present within the basin. Faulting and structural uplift have continued into the Recent epoch, necessitating a physiographic subdivision into an early and a late phase. Changes in the courses of the Ganges and Brahmaputra rivers through Bengal during the last few hundred years can be attributed to faulting and resultant tilting of fault blocks. These changes have caused the Ganges to abandon numerous western distributaries in favor of joining the Brahmaputra-Meghna system to the southeast. At present about 12,000 square miles of former Ganges deltaic plain in southwest Bengal has been abandoned. A series of surface echelon faults plus evidence of structural control of stream courses suggest the presence of a subsiding structural trough or major fault at depth. This active structural zone apparently has controlled both the Brahmaputra and Ganges rivers in their lower reaches. Subsurface information is lacking, but this subsiding trough may possibly be related to the arcuate chain of mountains in adjacent Burma.
Summer synoptic‐scale waves over West Africa observed by TRMM

A 5‐year daily rainfall dataset (3B42) from TRMM is used to investigate the activity and properties of westward‐propagating synoptic‐scale waves [i.e., African easterly waves (AEW)] over tropical West Africa. Evident wave signals appearing in wavenumber‐frequency space show their modulations on the surface rainfall pattern during the boreal summer. Interannual variability exists in both their intensity and spectral properties, i.e., dominant frequency and wavenumber ranges. These variabilities can be ascribed in part to year‐to‐year variations of their embedded large‐scale environment, especially the mid‐tropospheric African easterly jet (AEJ). Generally, a stronger (weaker) AEJ indicates more (less) instability energy, yielding a stronger (weaker) wave activity season. Both seasonal mean rainfall and AEWs were weak in 2001 but not in 1999. Consequently, there may exist a nonlinear relationship between the AEJ, AEWs and mean rainfall. To fully understand interannual variability of synoptic‐scale waves over tropical West Africa, including the variability in the waves' preferred frequencies and wavenumbers, it is necessary to examine possible intra‐seasonal variations in both wave activity and large‐scale fields, in addition to their structure, propagation, and associated convection.
Two‐dimensional simulations of gradient‐drift turbulence in the daytime equatorial electrojet

Two-dimensional numerical simulations of type II irregularities, attributed to gradient-drift instabilities, are carried out with observed profiles in the daytime equatorial electrojet. Earlier work has shown that these profiles are linearly unstable to gradient-drift modes with peak growth rates at wavelengths of the order of 1 km. The nonlinear evolution of these instabilities leads to saturated turbulent structures, with the linear drive at kilometer-scale wavelengths quenched by a direct energy cascade to short wavelengths that are effectively damped by velocity shear and diffusion. The saturated turbulent structures show quasi-steady 1 – 2 km horizontal waves, and appear to be quite isotropic in the plane perpendicular to the ambient magnetic field. The electron vertical velocity spectra, constructed from the simulation output, show 1–2 km vertical structures which are qualitatively in accord with recent high-resolution radar observations at the Jicamarca Observatory in Peru.
Provenance of the Upper Cretaceous–Eocene Deep-Water Sandstones in Sangdanlin, Southern Tibet: Constraints on the Timing of Initial India-Asia Collision

The first arrival of sedimentary material from Asia onto the Indian continental margin provides a minimum constraint on the timing of initial India-Asia collision. A combination of petrology, detrital Cr-spinel geochemistry, and zircon U-Pb dating of the Upper Cretaceous to Eocene deep-water succession at the Sangdanlin section, southern Tibet, provides evidence for major provenance change within the strata. The Upper Cretaceous–Paleocene Denggang Formation quartzarenites contain zircons with dominant Proterozoic-Ordovician U-Pb ages, with an additional age peak of Early Cretaceous, which we interpret to be derived from the northern Indian margin. By contrast, the lithic sandstones of the Early to Middle Eocene Sangdanlin and Zheya formations are dominated by zircons younger than 200 Ma, showing one major peak at ∼80–125 Ma and two subdominant peaks at ∼54–70 and ∼180–196 Ma, comparable to those from the Gangdese magmatic arc. Cr-spinels in the Sangdanlin and Zheya formations are abundant and characterized by extremely low TiO2 wt%, indicating an ophiolitic source. We consider the Sangdanlin and Zheya formations syncollisional, deposited in a foredeep basin, with the provenance being the Gangdese arc and the Yarlung Zangbo suture zone. The abrupt sedimentary provenance change between the Denggang and Sangdanlin formations denotes the onset of India-Asia continental collision occurring before the late Ypresian (∼50 Ma). Comparison of our data with those from coeval strata along the Himalaya suggests limited diachroneity in the India-Asia continental collision process.
Vertical roughness of Mars from the Mars Orbiter Laser Altimeter

The vertical roughness of the martian surface at ∼250 m spatial scales has been determined in two global latitude bands: an equatorial and a high northern band acquired from 18 tracks of data by the Mars Orbiter Laser Altimeter (MOLA) during the Fall of 1997. The distribution of RMS vertical roughness, as derived from MOLA pulse widths, for the equatorial band is non‐gaussian, with an overall mean of 2.8 m RMS, but with secondary populations at 1.5 m and 2–6 m RMS. The higher latitude northern plains of Mars are almost uniformly ∼1 m RMS in their vertical roughness characteristics, suggesting that they are smoother than virtually any terrestrial deserts. We suggest that dust mantling has muted the local topography of Mars, rendering it as smooth as 1–2 m RMS. Heavily cratered uplands near the martian equator are noticeably rougher, indicating more rugged and less‐mantled local topography.