Miracle-dz/UniFAR-FTUs huggingface dataset:
The origin and diagenesis of cherts from Cyprus

The Troodos Massif of Cyprus is overlain by a variety of cherts in pelagic chalks, volcanogenic sediments, radiolarites and radiolarian mudstones, all of Campanian to Upper Eocene age. There are two chert types, granular chert and vitreous chert. X-ray diffraction (XRD) reveals the silica polymorphs, disordered cristobalite and quartz. Silicification of the chalks varies from incipient, to bedded, granular cherts, all with disordered cristobalite as the main silica phase. Quartzitic cherts are restricted to the base of Upper Palaeocene and Lower Eocene calciturbidite beds. Disordered cristobalite predominates in the radiolarian mudstones at the foot of the sequence. The form of disordered cristobalite in cavities ranges from microspherules of radiating bladed crystals, the ‘lepispheres’ of the Deep Sea Drilling Project (DSDP) to bladed overgrowths, and fibrous silica. In contrast, within the fine grained matrix, the disordered cristobalite takes the form of partly coalescent crude microgranules and microspherules. Most of the chalcedonic quartz in Cyprus is derived by recrystallization of previously inorganically precipitated disordered cristobalite rather than by direct precipitation. According to the concept of impurity-controlled maturation the composition of host sediment controls the incorporation of exchangeable cations and other impurities into inorganically precipitated disordered cristobalite. With time (up to 100 million years) internal solid state reorganization of the disordered cristobalite is accompanied by gradual expulsion of impurities, until the cristobalite dissolves followed by quartz precipitation. Complete conversion to quartz takes place first in porous calcareous sediments free of impurities, as in the Cyprus calciturbidites; in fine grained clay-rich sediments, like Cyprus radiolarian mudstones, disordered cristobalite persists much longer. Impurity-controlled maturation also helps explain the diagenesis of Cyprus chert nodules.
Contribution of atmospheric internal processes to the interannual variability of the South Asian summer monsoon

Apart from the external forcings, the interannual variability of the South Asian summer monsoon can arise from atmospheric internal dynamics, although its mechanism has not been fully understood. Based on a three‐dimensional mean kinetic energy (MKE) budget equation, the contributions of internally generated processes associated with mean flow–transient eddy interaction and circulation–heating feedback to the interannual variability of the South Asian summer monsoon were diagnosed using two reanalysis data sets. In years with enhanced convections over South Asia, a strengthened low (high)‐level MKE related to southwesterly (easterly) jet is observed over the Arabian Sea. The enhancement of MKE at the low level is maintained by both the anomalous barotropic energy conversion between eddy kinetic energy (EKE) and MKE and the baroclinic energy conversion from mean available potential energy (MAPE) to MKE. Among the three‐dimensional barotropic energy conversion processes, the vertical eddy momentum flux interacting with the monsoon vertical wind shear anomaly plays a leading role in supporting the MKE anomaly. Moreover, the contribution of eddy activities related to the intraseasonal oscillation (ISO) of 20–90 days is larger than that of high‐frequency (<20 days) disturbances. This mean flow–ISO interaction dominates the atmospheric energy conversion processes and external boundary factors that may exert the interannual variations of monsoonal MKE in the lower troposphere. Different from the low‐level dynamics, scale interaction between eddies and the mean flow shows an insignificant contribution to the strengthening of the easterly jet in the higher troposphere. The Niño3. 4 sea surface temperature anomaly appears to be a key factor modulating the interannual variations of the high‐level monsoon easterly.
Geometry and grain‐size sorting of ripples on low‐energy sandy beaches: field observations and model predictions

ABSTRACT There are very few field measurements of nearshore bedforms and grain‐size distribution on low‐energy microtidal beaches that experience low‐amplitude, long‐period waves. Field observations are needed to determine grain‐size distribution over nearshore bedforms, which may be important for understanding the mechanisms responsible for ripple development and migration. Additional nearshore field observations of ripple geometry are needed to test predictive models of ripple geometry. Ripple height, length and sediment composition were measured in the nearshore of several low‐energy beaches with concurrent measurements of incident waves. The distribution of sediment sizes over individual ripples was investigated, and the performance of several models of ripple geometry prediction was tested both spatially and temporally. Sediment samples were collected from the crest and trough of 164 ripples. The sand‐sized sediment was separated from the small amount (generally <3%) of coarser material (>2 mm) that was present. Within the sand‐sized fraction, the ripple crests were found to be significantly coarser, better sorted and more positively skewed than the troughs. Overall, the troughs were finer than the crests but contained a greater proportion of the small fraction of sediment larger than 2 mm. The field model of Nielsen (1981 ) and the model of Wiberg & Harris (1994 ) were found to be the most accurate models for predicting the wavelength of parallel ripples in the nearshore of the low‐energy microtidal environments surveyed. The Wiberg & Harris (1994 ) model was also the most accurate model for predicting ripple height. Temporal changes in ripple wavelength appear to be dependent on the morphological history of the bed.
Theory and Evidence

Two puzzling facts of international migration are that only a small share of a sending country’s population emigrates and that net migration rates tend to cease over time. This paper addresses these issues in a migration model with heterogeneous agents that features temporary migration. In equilibrium a positive relation exists between the stock of migrants and the income differential, while the net migration flow becomes zero. Consequently, empirical migration models, estimating net migration flows instead of stocks, may be misspecified. This suspicion appears to be confirmed by our empirical investigation of cointegration relationships of flow and stock migration models.
China offshore wind energy resources assessment with the QuikSCAT data

With the data, which were obtained from the SeaWinds scatterometer on board the National Aeronautics and Space Administration (NASA) QuikSCAT satellite (12.5km*12.5km available from 1999 to current daily orbit swath), the China offshore region were studied (105-135° E 15-45° N). Because swath location is not fixed, interpolation was applied to get a fixed grid with 0.1° resolution. We calculate and analysis China offshore wind resources effective density of wind energy (EDWE) at 10 meters high above the sea level. And find that EDWE is rich in offshore area. The highest EDWE is in Taiwan Strait and North and South of the strait, with the EDWE 600-800W/m2, the next highest is East China Sea and South China Sea. The lowest EDWE is Yellow Sea and Bohai bay, less than 400W/m2. And several other wind energy resource-rich areas are: 1)the north of Bohai Bay, with wind power density more than 800 w/m2 decline to the south, 2)the East China Sea area the power density above 400 w/m2 increase to the southward. Guangdong coastal waters are rich in wind resources energy.
Fluid flow during exhumation of deeply subducted continental crust: zircon U‐Pb age and O‐isotope studies of a quartz vein within ultrahigh‐pressure eclogite

Quartz veins in high‐pressure to ultrahigh‐pressure metamorphic rocks witness channelized fluid flow that transports both mass and heat during collisional orogenesis. This flow can occur in the direction of changing temperature/pressure during subduction or exhumation. SHRIMP U‐Pb dating of zircon from a kyanite‐quartz vein within ultrahigh‐pressure eclogite in the Dabie continental collision orogen yields two age groups at 212 ± 7 and 181 ± 13 Ma, which are similar to two groups of LA‐ICPMS age at 210 ± 4 and 180 ± 5 Ma for the same sample. These ages are significantly younger than zircon U‐Pb ages of 224 ± 2 Ma from the host eclogite. Thus the two age groups from the vein date two episodes of fluid flow involving zircon growth: the first due to decompression dehydration during exhumation, and the second due to heating dehydration in response to a cryptic thermal event after continental collision. Laser fluorination O‐isotope analyses gave similar δ18O values for minerals from both vein and eclogite, indicating that the vein‐forming fluid was internally derived. Synchronous cooling between the vein and eclogite is suggested by almost the same quartz–mineral fractionation values, with regularly decreasing temperatures that are in concordance with rates of O diffusion in the minerals. While the quartz veining was caused by decompression dehydration at 700–650 °C in a transition from ultrahigh‐pressure to high‐pressure eclogite‐facies retrogression, the postcollisional fluid flow was retriggered by heating dehydration at ∼500 °C without corresponding metamorphism. In either case, the kyanite–quartz vein formed later than the peak ultrahigh‐pressure metamorphic event at the Middle Triassic, pointing to focused fluid flow during exhumation rather than subduction. The growth of metamorphic zircon in the eclogite appears to have depended on fluid availability, so that their occurrence is a type of geohygrometer besides geochronological applicability to dating of metamorphic events in orogenic cycles.
Snowmelt and Atmospheric Heating Processes over Eastern Mongolia

A shallow snowpack, such as that seen in Mongolia, easily melts through heating by the atmosphere. In turn, a snow-free surface without much meltwater heats the atmosphere quickly through heat fluxes at the surface. The present study investigated the snowmelt processes over eastern Mongolia during 2005−2007, using ground-observed temperature, snow depth, albedo, and radiation data. Moreover, we explored atmospheric influences on the snowmelt through the heat budget analysis of reanalysis data provided by the National Centers for Environmental Prediction. The results show that atmospheric heating over eastern Mon- golia during the snowmelt season is caused by the combination of vertical adiabatic heating in a traveling anticyclone and one-day- lagging horizontal advection after the passage of the anticyclone. These synoptic processes lead to a drastic increase in temperature and finally to substantial snowmelt under certain atmospheric conditions: the daily-mean surface air temperature exceeding −10 °C and downward longwave radiation exceeding 194 W m −2 under clear sky conditions.
Wind-Wave-Induced Disturbances in the Marine Surface Layer

Abstract Measurements of velocity and scalar fluctuations were made using a stable platform in Bass Strait at a height of ∼5 m above the mean surface of the ocean. These measurements were obtained over a period of time where the wind velocity increased steadily before reaching an approximately constant value that was maintained for a duration of ∼10 h. During the initial period of the experiment, induced wave fluctuations, centered about the dominant wave frequency, are observed an spectra of the longitudinal u and vertical w velocity fluctuations, and on the uw cross spectrum. The cross spectrum indicates a relatively important transfer of momentum in the direction sea to air, at the wave frequency. No measurable wave influence is detected on either temperature θ or humidity q spectra, but wθ and wq cross spectra are either negligible or show a change of sign at the wave frequency. Although the effect on w persists, wave-induced disturbances on the cross spectra are small enough to be neglected when the .
Spatial and temporal variability of surface water repellency in sandy loam soils of NW Spain under Pinus pinaster and Eucalyptus globulus plantations

This work was undertaken for two main purposes. One was to examine spatial and temporal variability in surface water repellency under field conditions in sandy loam forest soils of NW Spain, and its relationship to weather and soil moisture conditions. The other purpose was to get further inside in the dynamics of soil water repellency by studying a wetting–drying cycle under controlled laboratory conditions. Both for the field and laboratory study, water repellency was determined using the Water Drop Penetration Time test. Soil water repellency under field conditions was found to exhibit a seasonal pattern, i.e. it peaked during the summer and was absent between November and May. The time required for repellency to become re‐established during the spring was shorter under eucalyptus than under pine. Spatial variability peaked at an early stage of soil drying and was minimal during the wet period when soils were hydrophilic as well as at the end of the summer, when repellency was strongest. Spatial and temporal variability in water repellency was found to be negatively correlated with soil moisture and, to a lesser extent, with antecedent rainfall. The moisture range of the so‐called transition zone (below which the soil is hydrophobic and also above which it is hydrophobic) differed for the pine (21–50%) and eucalyptus plantations (17–36%). The lower and upper bounds of the transition zone agreed well with the soil moisture contents at the permanent wilting point and at field capacity, respectively. The laboratory results with samples in the wetting phase confirmed those of the field tests. Water repellency increased slightly during the drying phase, but not so much as in the field. Copyright © 2011 John Wiley & Sons, Ltd.
Can we distinguish flood frequency and magnitude in the sedimentological record of rivers

Consideration of the origin of alluvial deposits and their paleoenvironmental interpretation has traditionally involved two schools of thought: that they are either the result of processes that, on average, have acted uniformly through time, or that they are related to exceptional events that occur infrequently. Despite the long-running debate of gradualism versus catastrophism within the Earth Sciences, there are surprisingly few quantitative data to assess the magnitude of events that produce alluvial sedimentary successions. This paper reports on a unique ‘natural experiment’ where surface (digital elevation model, DEM) and subsurface (ground penetrating radar, GPR) data were taken immediately prior to, and after, a large (1-in-40 yr) flood event on the sandy, braided, South Saskatchewan River, Canada. Results show that although this high-magnitude flood reworked the entire braidplain, the scale of scour and style of deposition was similar to that associated with lower-magnitude, annual, floods. The absence of a distinct imprint of this large flood within the deposits is related to the fact that as river discharge rises, and begins to flow overbank, channel width increases at a much faster rate than flow depth, and thus the rate of increase in channel bed shear stress declines. Hence, rather than being a product of either frequent or rare events, alluvial deposits will likely be created by a range of different magnitude floods, but discriminating between these different scale events in the rock record may be extremely difficult.
High heat flow from Enceladus' south polar region measured using 10–600 cm−1 Cassini/CIRS data

[1] Analysis of 2008 Cassini Composite Infrared Spectrometer (CIRS) 10 to 600 cm−1 thermal emission spectra of Encleadus shows that for reasonable assumptions about the spatial distribution of the emission and the thermophysical properties of the solar-heated background surface, which are supported by CIRS observations of background temperatures at the edge of the active region, the endogenic power of Enceladus' south polar terrain is 15.8 ± 3.1 GW. This is significantly higher than the previous estimate of 5.8 ± 1.9 GW. The new value represents an improvement over the previous one, which was derived from higher wave number data (600 to 1100 cm−1) and was thus only sensitive to high-temperature emission. The mechanism capable of producing such a high endogenic power remains a mystery and challenges the current models of proposed heat production.
Europe (in Theory)

Europe (in Theory) is an innovative analysis of eighteenth- and nineteenth-century ideas about Europe that continue to inform thinking about culture, politics, and identity today. Drawing on insights from subaltern and postcolonial studies, Roberto M. Dainotto deconstructs imperialism not from the so-called periphery but from within Europe itself. He proposes a genealogy of Eurocentrism that accounts for the way modern theories of Europe have marginalized the continent’s own southern region, portraying countries including Greece, Italy, Spain, and Portugal as irrational, corrupt, and clan-based in comparison to the rational, civic-minded nations of northern Europe. Dainotto argues that beginning with Montesquieu’s The Spirit of Laws (1748), Europe not only defined itself against an “Oriental” other but also against elements within its own borders: its South. He locates the roots of Eurocentrism in this disavowal; internalizing the other made it possible to understand and explain Europe without reference to anything beyond its boundaries. Dainotto synthesizes a vast array of literary, philosophical, and historical works by authors from different parts of Europe. He scrutinizes theories that came to dominate thinking about the continent, including Montesquieu’s invention of Europe’s north-south divide, Hegel’s “two Europes,” and Madame de Stael’s idea of opposing European literatures: a modern one from the North, and a pre-modern one from the South. At the same time, Dainotto brings to light counter-narratives written from Europe’s margins, such as the Spanish Jesuit Juan Andres’s suggestion that the origins of modern European culture were eastern rather than northern and the Italian Orientalist Michele Amari’s assertion that the South was the cradle of a social democracy brought to Europe via Islam.
The thermal regime of a retrogressive thaw slump near Mayo, Yukon Territory

The development of a retrogressive thaw slump near Mayo, Yukon Territory, has been traced from initiation by bank erosion (~1949) of the Stewart River to stabilization in 1993-1994. The stabilized headwall of the slump is 450 m from the river, and the slope of the slump floor is 3°. A transect of the slump from the river to the stabilized headwall was drilled in July 1995, to determine the extent and rate of permafrost degradation in the slump floor. Thermistors were placed in access tubes to 12 m depth at five sites, four near the transect and one in undisturbed terrain, to determine the magnitude of thermal disturbance due to slump development. Data loggers at the sites recorded the ground temperature at 1 m depth for two years from August 1995. The annual mean ground temperatures measured by the data loggers varied between 1.2° and 1.8°C in the slump, compared with -2.4°C in undisturbed ground, indicating a disturbance of about 4°C due to slumping. The depth of thaw in the slump floor is consistent wit.
Nitrogen and carbon solution chemistry of an old growth coniferous forest watershed before and after cutting

Dissolved Kjeldahl N and nitrate concentrations were monitored for 1 to 2 years before and for 3 years after clearcutting of a 10.2-ha, Douglas-fir dominated watershed in the Oregon Cascade Mountains. Dissolved organic C (DOC) and ammonium concentrations were monitored after cutting. We sampled throughfall, litter leachate, and soil solution (at four depths in and below the rooting zone) at four locations along a transect up and down the slope. We also sampled precipitation, streamwater, and seepage water. A site just off of the watershed served as the control for all positions in the water profile except for streamwater, for which a similar, nearby watershed was the control. Objectives were (1) to document effects of clearcutting on solution chemistry and (2) to provide data from which to calculate ecosystem nutrient cycling budgets before and after cutting. Beginning 7–18 months after clearcutting, nitrate concentrations increased 3–100 times on the cut watershed but remained nearly unchanged on an adjacent, uncut, control area. Increases were greater at 2.0-m depth than at other positions along the water profile and least in seepage and streamwater. Greatest nitrate levels were detected near the bottom of the slope. At the uppermost site, about 50 m below the ridgetop, nitrate values remained the same as at the control site. Concentrations of Kjeldahl N (organic N plus ammonium) increased much less than those of nitrate (only 50–100% over precut levels) but were greater than nitrate concentrations at most profile positions both before and after cutting. Even after cutting, nitrate dominated only at 2.0-m depth and in seepage water. DOC concentrations were slightly greater on the cutover area than on the control. However, they increased as much as 3 times from year 2 to year 3 after cutting at both treated and control sites, whereas nitrate decreased from year 2 to 3, and Kjeldahl N increased little or remained the same. DOC concentrations decreased consistently with depth in the soil profile. The study showed (1) that dissolved organic N must be measured if total N transfers are to be calculated at most sites, (2) that patterns of nitrate appearance can be explained in part on the basis of decreased availability of oxidizable C, (3) that patterns of nitrate appearance after devegetation vary greatly with depth in the soil and with slope position, and (4) that loss of dissolved N after cutting was small (<2.0 kg ha−1 yr−1) compared with nearly 400 kg N ha−1 removed in tree boles.
A glacial stage spanning the antarctic cold reversal in torres del paine (51°s), chile, based on preliminary cosmogenic exposure ages

ABSTRACT. Initial cosmogenic 10Be results from a former ice limit in Torres del Paine indicate a shortlived stillstand or readvance of Patagonian ice culminating at 12–15 kyr BP with a mean age of 13.2 ± 0.8 kyr BP. The glacier extended some 40 km beyond the present ice margin and was within 15 km of the presumed Last Glacial Maximum limits. The timing of the glacier stage spans the cooling event recorded in Antarctic ice cores, termed the Antarctic Cold Reversal (14.5–12.9 kyr BP). This result implies that glaciers at these latitudes were out of phase with those in the northern hemisphere; instead they mirrored the climate structure of Antarctica during the last glacial to interglacial transition.