Miracle-dz/UniFAR-FTUs huggingface dataset:
Structural, petrological and thermal evolution of a tertiary ductile strike-slip shear zone, Diancang Shan, Yunnan

The Diancang Shan, a horst massif within the Red River fault zone in Yunnan, People's Republic of China, preserves a structural, petrological, and thermal record of two distinct phases of tectonic activity: a left-lateral ductile shear that terminated between 20 and 17 Ma and a ductile-to-brittle phase of normal faulting which began at 4.7 Ma and remains active. Mylonitic rocks in the core of the range display an early, steep, high-temperature (HT), schistosity and a horizontal stretching lineation that are both parallel to the trend of the belt. Kinematic indicators indicate that shear was left-lateral. The complex shape of the HT schistosity at the southern termination of the massif likely results from a large-scale, oblique, left-lateral C' shear plane that dismembered the shear zone and separated the Ailao Shan and the Diancang Shan as left-lateral deformation terminated. Thermochronological and thermobarometric results suggest that the gneisses were partially unroofed during this event. Along the eastern edge of the Diancang Shan, the HT fabrics were overprinted by low-temperature structures during activation of east dipping normal faults. Cooling associated with this normal/right-lateral faulting along the Diancang Shan (and perhaps activation of the right-lateral/normal movement on the Range Front fault farther south along the Ailao Shan) began at 4.7±0.1 Ma. These results tend to support the view that extrusion of Indochina occurred along the left-lateral Red River shear zone between 35 and 19–17 Ma. Initiation of right-lateral/normal slip during the late Miocene may relate to eastward extensional collapse of the thickened Tibetan crust or, more probably, to initiation of the second phase of extrusion.
Pitfalls in synthetics

The primary goal of seismic interpretation is to make maps that provide geologic information (reservoir depth structure, thickness, porosity, etc.). However, even ideally acquired/processed seismic data provide only an image of the subsurface. For geologic information, nearby wells must be correlated to seismic reflectors. Synthetic seismograms (synthetics) provide this link by converting rock properties from well logs to a synthetic trace.
Microbial ecosystems of Antarctica

Preface 1. Introduction 2. Snow and ice ecosystems 3. Sea-ice ecosystems 4. The marginal-ice zone 5. The open ocean 6. Benthic marine environments 7. Lakes and streams 8. Soil ecosystems 9. Lithic ecosystems: the rock environments 10. Microbial strategies in Antarctica 11. Microbes and humans in Antarctica Glossary Appendixes References Index.
First measurements and modeling of Δ17O in atmospheric nitrate

Atmospheric nitrate is anomalously enriched in both the 18O/16O and 17O/16O isotopic ratios, with Δ17O = 20–30.8‰ (Δ17O = δ17O − .52 × δ18O). We have modeled the seasonal variation in Δ17O by utilizing the transfer of Δ17O from ozone to HNO3 during NOx oxidation reactions and by evaluating the relative source strengths of heterogeneous and homogenous HNO3 production. The implications for new insights into the global nitrogen cycle, N2O production and paleoclimate studies are discussed.
Shear wave anisotropy in the upper mantle beneath the Nazca Plate in northern Chile

Data from the Projecto de Investigacion Sismologica de la Cordillera Occidental (PISCO) seismic network and from six broadband seismographs that were operating in northern Chile were used to investigate the mantle in the convergent boundary zone between Nazca plate and the South American continent for the presence of anisotropy. Broadband data as well as long-period filtered data of teleseismic SKS and PKS phases were analyzed for the presence of shear wave splitting as a possible indicator for seismic anisotropy in the mantle beneath the PISCO network. Measurable shear wave splitting was observed with maximum delay times between the slow and fast split wave of the order of 1 s. Splitting of S waves from intermediate-depth events located directly beneath the PISCO network in the descending Nazca plate is generally associated with small delay times of the order of 0.1 s, a value typical for the continental crust. Near-vertical ScS reflections from two deep earthquakes in Argentina and one nearby intermediate-depth earthquake have similar splitting parameters as the SKS phases. This means that the anisotropic zone causing the splitting of the core phases can be constrained to the Pacific mantle underlying the subducting Nazca plate. It probably does not extend deeper than about 260 km. The majority of the anisotropy directions inferred from the core phases are parallel to the absolute plate motion (APM) direction of the Nazca plate, which is about N80°E. At some stations, however, the fast polarization direction is pointing N160°E, nearly parallel to the strike of the trench and the Andes which would be compatible with the trench-parallel flow model for South America proposed by Russo and Silver [1994]. This direction is observed over an approximately 100-km-wide band to the west of the active volcanic zone. It may represent either a second anisotropy regime in the mantle, a small-scale diversion of slab-entrained mantle flow, or a relatively small area where slab entrainment of mantle flow is reduced or ceases to exist. The large number of observed APM-parallel fast directions suggests, however, that the mantle beneath the descending Nazca plate in northern Chile deforms mainly as the result of slab-entrained mantle flow. The large variations of anisotropy directions in the Andean subduction zone indicate that asthenospheric flow in the Pacific mantle has a complex pattern which may vary over scale lengths of a few hundred kilometers and which may be governed by slab morphology.
Low-flow characteristics of streams in the St. Croix River basin, Wisconsin

The purpose of this report is to describe low-flow characteristics of streams in the St. Croix River basin where streamflow data have been collected and to present equations for estimating low-flow characteristics at ungaged sites. Included are estimates of low-flow frequency and flow duration at 7 gaging stations, and low-flow frequency characteristics at 26 low-flow partialrecord stations and 75 miscellaneous sites. Four equations are provided to estimate low-flow characteristics at ungaged sites and at sites where one base-flow discharge measurement is available. The low-flow characteristics determined were the annual minimum 7-day mean flow below which the flow will fall on an average of once in 2 years (Q7 9 2) and once in 10 years (Q7 s io)« The equations were determined from multiple-regression analyses that related the low-flow characteristics at gaging stations and lowflow partial-record stations to basin characteristics. Drainage area (A) was the most significant characteristic in explaining the variations in low flow for ungaged sites. The equations and standard error of estimates (SE) for ungaged sites are: 2 = 3.75X10"2A1 * 3° SE 2 = 110 percent nn = 1.05x10"" A * ' SE^ __ = 150 percent 10 7»io For sites where one base-flow measurement has been made drainage area (A) and base-flow index (Bf) were the most significant characteristics. The equations and standard error of estimate are: QT 2 = O.U92A1 Bf1 ' 01 SE 2 = 38 percent _ = 0.235A1 ' 28Bf1 ' 21 SEV nn = 52 percent
Factors controlling the flux of organic carbon to the bathypelagic zone of the ocean

Particle fluxes measured with time series sediment traps deployed below 2000 m at 68 sites in the world ocean are combined with satellite‐derived estimates of export production from the overlying water to assess the factors affecting the transfer of particulate organic matter from surface to deep water. Multiple linear regression is used to derive an algorithm suggesting that the transfer efficiency of organic carbon, defined as the settling flux of organic carbon normalized to export production, increases with the flux of carbonate and decreases with water depth and seasonality. The algorithm predicts >80% of the organic carbon transfer efficiency variability in diverse oceanic regions. The influence of the carbonate flux suggests that the ballasting effect of this biogenic mineral may be an important factor promoting export of organic carbon to the deep sea by increasing the density of settling particles. However, the lack of a similar effect for biogenic opal suggests that factors other than particle density also play a role. The adverse effect of increasing seasonality on the transfer efficiency of carbon to the deep sea is tentatively attributed to greater biodegradability of organic matter exported during bloom events. In high latitude opal‐dominated regions with high f‐ratios and seasonality, while a higher fraction of net production is exported, a higher fraction of the exported organic matter is remineralized before reaching bathypelagic depths. On the other hand, in warm, low latitude, carbonate‐dominated regions with low f‐ratios and seasonality, a higher fraction of the exported organic matter sinks to the deep sea.
Production of the greenhouse gases CH4 and CO2 by hydroelectric reservoirs of the boreal region

The emission fluxes and the distribution of dissolved methane (CH4) and carbon dioxide (CO2) were determined for 11 sampling stations in two hydroelectric reservoirs (flooded since 1978 and 1993) located in the James Bay territory of northern Quebec. The measured benthic fluxes for the two greenhouse gases were found to be either higher or similar to those determined at the water-air interface during the ice-free sampling periods. For the 2 year duration of the study, emission fluxes of CH4 to the atmosphere generally varied between 5 and 10 mg m−2 d−1, while those for CO2 ranged from 500 to 1100 mg m−2 d−1. Furthermore, through the use of static chambers at the water-air interface, we determined that the emission fluxes for the gases are controlled by molecular diffusion. Our calculated fluxes have been separated into two groups: (1) regular emission fluxes and (2) above-average emission fluxes. The first type comprises the majority of fluxes measured during the sampling periods (i.e., 88% for CH4 and 87% for CO2). The second group reflects unusual sampling conditions (e.g., strong winds, water column depths of less than 1 m, or flooded peatland mats floating at the surface). Although data for this group are limited, our preliminary results suggest that they may be an important component in an atmospheric emissions budget for large reservoirs. Concentration profiles for CH4 and CO2 dissolved in the water column clearly show that oxidation and/or horizontal advection of these gases are controlling factors in their subsequent release to the atmosphere. Most of the CH4 is oxidized within the first 25 cm above the flooded soil-water interface. Consequently, neither benthic emissions of CH4 and CO2 nor the type of flooded soil appear to control atmospheric emissions of these gases from hydroelectric reservoirs.
Binge/purge oscillations of the Laurentide Ice Sheet as a cause of the North Atlantic's Heinrich events

Ice-rafted debris in sediment cores from the North Atlantic suggests that the Laurentide ice sheet (LIS) periodically disgorged icebergs in brief but violent episodes which occurred approximately every 7,000 years. Here, I propose that Heinrich events (i.e., what these episodes are called) were caused by free oscillations in the flow of the Laurentide ice sheet which arose because the floor of Hudson Bay and Hudson Strait is covered with soft, unconsolidated sediment that forms a slippery lubricant when thawed. The proposed Heinrich event cycle has two phases. The growth phase occurs when the sediment is frozen and the LIS is stranded (immobile) on a rigid bed. The volume of the LIS slowly grows during this phase at a rate dictated by snow accumulation. The purge phase occurs when the basal sediment thaws and a basally lubricated discharge pathway (i.e., an ice stream such as those which occur in West Antarctica today) developes through Hudson Strait. The volume of the LIS rapidly equilibrates to the reduced basal friction during this phase by dumping icebergs into the Labrador Sea. The periodicity T=π/κ(−kθsl2G∼)2≈7000 years of the proposed Heinrich event cycle is a function of the thermal conductivity and diffusivity of ice, k and κ, respectively, the atmospheric sea level temperature θsl (in degrees Celsius), and the excess geothermal heat flux defined by G∼=G−kΓ where Γ is the atmospheric lapse rate, and G is the geothermal heat flux. Agreement between the predicted T and the apparent periodicity implied by the marine record is the main virtue of the free oscillation mechanism I propose. An alternative mechanism in which Heinrich events are forced by periodic variations in external climate is implausible, because periodic atmospheric temperature perturbations are strongly attenuated with depth in an ice sheet.
The Pachuca obsidian source, Hidalgo, Mexico: A geoarchaeological perspective

Sierra Las Navajas, known to archaeologists as “the Pachuca obsidian source,” has been a major source of obsidian to Mesoamerican societies for more than 3000 years, producing a fine green obsidian unique in Middle America. It was the primary source of the obsidian that formed the economic backbone of the major sociopolitical centers of Classic period Teotihuacán, epi‐Classic Toltec Tula, and Aztec Tenochtitlán. In this paper, the obsidian of Sierra Las Navajas is discussed in the following contexts: (1) geologically, because the extraordinary quality of the Pachuca obsidian, its ease of extraction, and its distinctive color and chemistry are a direct result of its geologic emplacement; (2) locally, as the different mining localities within Sierra Las Navajas reflect the varying needs of the cultures working them; and (3) globally, as the obsidians of Las Navajas were used in concert with obsidians from other sources, and were traded great distances across Mesoamerica. © 2004 Wiley Periodicals, Inc.
East Asia: China, Japan, Korea, Vietnam : geography of a cultural region

These strictures are made with real regret: the reviewer still remembers warmly the excitement with which he reviewed the first edition 17 years ago. By no means all of the bright insights of 1954 are sadly faded by 1971; but too many of them are, and not a great deal of new insight has been gained from the experience of the last two decades—or at least it has not been presented here. For that, the conditions of American academic publishing rather than the authors may really be responsible. There is still a great deal of value in this edition of Asia, east by south, but there is also too much that has become dead wood in these last turbulent years, and that should have been excised. One cannot, unfortunately, escape the feeling that an opportunity has been missed: that the potential of the authors, which is very considerable, has been dissipated in a routine revision of a book which needed and deserved a more liberal and forward-looking treatment. As an introduction to Asian themes for the college student, the book can still be recommended; but not, alas, with the old enthusiasm. The Australian National University o. H. K. SPATE
¿Cómo influyen la edad y el género en la capacidad de cambiar de dirección en alumnos de educación primaria? (How does the age and gender influence the ability to change direction in primary school children?)

The main objective of this study was to determine the influence of age and gender on the ability to change direction (CODA) in primary education children's. This study involved 343 children (8.2 ± 1.1 years, 143.2 ± 8.7 cm, 37.8 ± 9.9 kg) students in first, second, third and fourth year of primary education. To evaluate the change of direction ability (CODA) the Modified Agility Test (MAT) was use. The results showed significant differences (F(3) = 56.25, p = 0.000) between the age groups. Differences in CODA between boys and girls have not manifested through the fourth grade (t(56) = -2.30, p = 0.02) in primary education students. By age and gender, the development of boys and girls was different. These results may lead us to think about the need to implement specific programs to improve the CODA at different times depending on age and gender.
Mélange rheology and seismic style

Shear displacements in crustal fault zones are accommodated by a range of seismic styles, including standard earthquakes, non-volcanic tremor, and continuous and transitory aseismic slip. Subduction channel shear zones, containing highly sheared, fluid-saturated trench-fill sediments intermingled with fragments of oceanic crust, are commonly inferred to occur along active subduction megathrusts. If this interpretation is correct, these plate boundary faults are not discrete planes, but may resemble the melange shear zones commonly found in exhumed subduction-related rock assemblages. Melange deformation appears to depend critically on the ratio of competent to incompetent material, with shear surfaces localized along lithological contacts or within competent domains, while matrix flow accommodates shearing by distributed strain. If the style of strain and/or displacement accommodation in a melange reflects the partitioning between aseismic and seismic slip, the proportion of competent material seems likely to be a significant factor affecting seismic style within subduction channel shear zones, and along comparable mixed-lithology fault zones.
Hydrological influences on spatiotemporal variations of δ15N and δ18O of nitrate in a forested headwater catchment in central Japan: Denitrification plays a critical role in groundwater

[1] To elucidate the internal nitrogen cycle and nitrogen input and output, we measured δ15N-NO3−, δ18O-NO3−, and NO3− concentrations in rainfall, soil water from an unsaturated soil horizon, groundwater, and stream water at a small forested headwater catchment. In soil water, the mean NO3− concentration did not decrease concomitantly with soil depth, despite a drastic decrease of δ18O-NO3− with soil depth, indicating immediate consumption of atmospheric NO3− and production of nitrified NO3−. The spatiotemporal distribution of δ15N-NO3− and δ18O-NO3− in soil water indicated that plant uptake contributed mainly to NO3− consumption and that denitrification was negligible. In contrast, denitrification played a critical role in groundwater in decreasing the NO3− concentration. Fluctuations of δ15N-NO3−, δ18O-NO3−, and NO3− concentration in groundwater, however, differed from expectations for occurrence resulting from denitrification only. A plausible explanation for the lack of a concurrent increase in δ15N and δ18O of NO3− is that nitrification and denitrification occur concurrently in groundwater and that denitrification is more important than nitrification. The amount of denitrification in the groundwater body was controlled primarily by groundwater residence time. The combination of hydrological flow path from groundwater to stream water and denitrification in the groundwater critically control the amount of leaching of NO3− and temporal distribution of NO3− concentration in stream water. The possibility exists that denitrification in groundwater strongly influences nitrogen leaching in forests because denitrification occurred even in this catchment, which consists of weathered granitic bedrock and predominantly typic udipsamment, with low organic matter content in the soil.
Testing solar forcing of pervasive Holocene climate cycles

The temporal and spatial extent of Holocene climate change is an area of considerable uncertainty, with solar forcing recently proposed to be the origin of cycles identified in the North Atlantic region. To address these issues we have developed an annually resolved record of changes in Irish bog tree populations over the last 7468 years which, together with radiocarbon‐dated bog and lake‐edge populations, extend the dataset back to ∼9000 yr ago. The Irish trees underpin the internationally accepted radiocarbon calibration curve, used to derive a proxy of solar activity, and allow us to test solar forcing of Holocene climate change. Tree populations and age structures provide unambiguous evidence of major shifts in Holocene surface moisture, with a dominant cyclicity of 800 yr, similar to marine cycles in the North Atlantic, indicating significant changes in the latitude and intensity of zonal atmospheric circulation across the region. The cycles, however, are not coherent with changes in solar activity (both being on the same absolute timescale), indicating that Holocene North Atlantic climate variability at the millennial and centennial scale is not driven by a linear response to changes in solar activity. Copyright © 2005 John Wiley & Sons, Ltd.
Reynolds Stresses and Velocity Distributions in a Wave-Current Coexisting Environment

To investigate changes in the mean velocity profile owing to the interaction between waves and a current, the horizontal and vertical velocity components in the oscillating fluid were measured by a two-dimensional laser anemometer in a recirculating wave tank. The observed instantaneous velocity data concerning waves following and opposing a current were analyzed to obtain the Eulerian-mean velocity, the wave-current Reynolds stress, and the wave-current turbulent intensities. The wave-current Reynolds stress behaves differently when current direction changes. The general characteristic of the Eulerian-mean velocity is greatly affected by the wave-current Reynolds stress. The mean velocity for waves following (opposing) a current is reduced (increased) towards the free surface, when compared with the logarithmic profile. These velocity data were used to verify the results by velocity equations based on the phase-averaged Prandtl momentum-transfer theory. In addition, measurement of water-surface elevations revealed that the phase-averaged waveform for a pure wave is peaked near the crest but flatter near the trough and the variation of the water surface is well predicted by the third-order Stokes wave equation. The original pattern of the waveform varies due to the wave-current interaction, but the current direction only minimally affects the attenuation of the surface waves.
Atmospheric versus vegetation controls of Amazonian tropical rain forest evapotranspiration: Are the wet and seasonally dry rain forests any different?

[1] This study analyzes evapotranspiration data for three wet and two seasonally dry rain forest sites in Amazonia. The main environmental (net radiation, vapor pressure deficit, and aerodynamic conductance) and vegetation (surface conductance) controls of evapotranspiration are also assessed. Our research supports earlier studies that demonstrate that evapotranspiration in the dry season is higher than that in the wet season and that surface net radiation is the main controller of evapotranspiration in wet equatorial sites. However, our analyses also indicate that there are different factors controlling the seasonality of evapotranspiration in wet equatorial rain forest sites and southern seasonally dry rain forests. While the seasonality of evapotranspiration in wet equatorial forests is driven solely by environmental factors, in seasonally dry forests, it is also biotically controlled with the surface conductance varying between seasons by a factor of approximately 2. The identification of these different drivers of evapotranspiration is a major step forward in our understanding of the water dynamics of tropical forests and has significant implications for the future development of vegetation-atmosphere models and land use and conservation planning in the region.