Reconstructing deep‐time histories from integrated thermochronology: An example from southern Baffin Island,Canada     

Kalin T. McDannell  David A. Schneider  Peter K. Zeitler  Paul B. O'Sullivan  Dale R. Issler 《地学学报》2019,31(3):189-204

We present a multi‐chronometric approach for reconstructing deep‐time thermal histories using southern Baffin Island as a case study. This continuous thermal history begins with the Palaeoproterozoic Trans‐Hudson Orogeny and is derived from inverse and forward models that integrate thermochronometers spanning some 500°C: new apatite U–Pb ages and K‐feldspar ⁴⁰Ar/³⁹Ar multi‐diffusion domain data, published (U–Th)/He zircon ages and new multi‐kinetic fission‐track results. Integration of data from a wider temperature range reduces ambiguities in thermal‐history modelling and permits us to constrain the timing of geological processes including, extended post‐orogenic cooling, enhanced later Proterozoic cooling, and then episodic burial and exhumation in the Palaeozoic–Mesozoic.  相似文献   

Comparing the Validity and Reliability of Place Attachment Across Cultures     

Christopher J. Wynveen  Ingrid E. Schneider  Stuart Cottrell  Arne Arnberger  Alexander C. Schlueter  Eick Von Ruschkowski 《社会与自然资源》2017,30(11):1389-1403

Researchers often measure human–place bonds via place attachment scales across a variety of settings. However, scale use does not always include an evaluation of the scales’ psychometric properties, especially in multisite studies. Failure to consider a place attachment scale’s measurement properties makes both validity and reliability assumptions and may lead to improper data interpretation. Hence, this investigation assessed a place attachment scale across three sites via data collected on site in natural resource protected areas in Colorado, Minnesota, and Germany. A series of confirmatory factor analyses assessed the hypothesized two-dimensional (i.e., place identity and place dependence) model, Cronbach’s alphas calculated a measure of internal consistency, and a multigroup procedure cross-validated the scale. Some items did not load on the hypothesized dimension and the pattern of factor loadings was not equivalent across settings, suggesting assessment of place attachment scales may be necessary when used in new contexts.  相似文献   

Microcrater populations on Apollo 17 rocks     

E. Schneider  F. Hörz 《Icarus》1974,22(4):459-473

Approximately 6000 microcrates were investigated using binocular microscope techniques on Apollo 17 rocks 70215, 72215, 72235, 72395, 72435, 73216, 73218, 73275, 74275, 76135, 76136 and 79155. The crater populations observed have identical characteristics to those obtained from previous missions.Special emphasis was placed on assessing the influence of target properties on the observable crater populations. Although these properties cannot be quantitatively evaluated at present, the empirical results indicate that crater populations on glass, breccia, and crystalline rock surfaces may differ fundamentally. As a consequence, lunar surface exposure ages of individual rocks based on micrometeoroid craters may be subject to criticism.  相似文献   

Cosmic-ray positrons: are there primary sources?     

Stphane Coutu  Steven W. Barwick  James J. Beatty  Amit Bhattacharyya  Chuck R. Bower  Christopher J. Chaput  Georgia A. de Nolfo  Michael A. DuVernois  Allan Labrador  Shawn P. McKee  Dietrich Müller  James A. Musser  Scott L. Nutter  Eric Schneider  Simon P. Swordy  Gregory Tarl  Andrew D. Tomasch  Eric Torbet 《Astroparticle Physics》1999,11(4):208-435

Galactic cosmic rays consist of primary and secondary particles. Primary cosmic rays are thought to be energized by first order Fermi acceleration processes at supernova shock fronts within our Galaxy. The cosmic rays that eventually reach the Earth from this source are mainly protons and atomic nuclei, but also include electrons. Secondary cosmic rays are created in collisions of primary particles with the diffuse interstellar gas. They are relatively rare but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, positrons and antiprotons. In addition, positrons and antiprotons may also come from unusual sources and possibly provide insight into new physics. For instance, the annihilation of heavy supersymmetric dark matter particles within the Galactic halo could lead to positrons or antiprotons with distinctive energy signatures. With the High-Energy Antimatter Telescope (HEAT) balloon-borne instrument, we have measured the abundances of positrons and electrons at energies between 1 and 50 GeV. The data suggest that indeed a small additional antimatter component may be present that cannot be explained by a purely secondary production mechanism. Here we describe the signature of the effect and discuss its possible origin.  相似文献   

A simultaneous maximum likelihood approach for galaxy--galaxy lensing and cluster lens reconstruction     

Bernhard Geiger  Peter Schneider 《Monthly notices of the Royal Astronomical Society》1999,302(1):118-130

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Gravitational wave background from a cosmological population of core-collapse supernovae     

Valeria Ferrari  Sabino Matarrese  Raffaella Schneider 《Monthly notices of the Royal Astronomical Society》1999,303(2):247-257

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沈北煤田煤中琥珀的植物来源和稳定同位素的古环境意义     

刘帮军  田泽奇  李鸿豆  郭旭  赵巧静  石志祥  郭文牧  张宁  Achim BECHTEL  Maksim G BLOKHIN  孙玉壮  赵存良 《地质学报》2023,97(8):2445-2458

琥珀是由古代植物代谢产生的树脂聚合物形成的化石。琥珀中的有机质保存环境稳定、封闭,能很好地记载其形成时期的古植物和古环境等信息。本次研究运用气象色谱质谱联用仪（GC-MS）和元素分析稳定同位素质谱仪（EA-IRMS）等测试方法,研究了沈北煤田煤中琥珀的有机地球化学组成、稳定同位素和化合物单体碳同位素特征。结果表明,琥珀中的饱和烃以二萜化合物为主（占73.45%）,芳香烃以松香烷型化合物为主（56.17%）;高含量的贝壳杉烷、雪松烷、扁枝烷和松香烷型化合物指示琥珀来源于松柏类植物,且以柏科植物为主。沈北琥珀的δ13C值为-22.8‰ ~ -21.2‰,与同时期其他地区琥珀的δ13C值相似;氢同位素变化范围较小（-297.2‰ ~ -276.0‰）,氧同位素值为17.4‰ ~ 31.6‰。琥珀的稳定同位素组成（碳、氢和氧）进一步证明琥珀来源于裸子植物。琥珀的δ13C值主要与其形成时的全球气温变化和大气组成有关。沈北琥珀的氢和氧同位素组成主要受植物种类（松柏类）以及植物生长的局部气温和降水条件有关。琥珀稳定碳同位素有望成为研究古气候和古大气组成的良好载体,琥珀的氢和氧同位素可以反映形成时期的古环境条件,但仍需进一步深入研究。  相似文献   

GPCC's new land surface precipitation climatology based on quality-controlled in situ data and its role in quantifying the global water cycle   总被引：10，自引：3，他引：10  

Udo Schneider  Andreas Becker  Peter Finger  Anja Meyer-Christoffer  Markus Ziese  Bruno Rudolf 《Theoretical and Applied Climatology》2014,115(1-2):15-40

In 1989, the need for reliable gridded land surface precipitation data sets, in view of the large uncertainties in the assessment of the global energy and water cycle, has led to the establishment of the Global Precipitation Climatology Centre (GPCC) at Deutscher Wetterdienst on invitation of the WMO. The GPCC has calculated a precipitation climatology for the global land areas for the target period 1951–2000 by objective analysis of climatological normals of about 67,200 rain gauge stations from its data base. GPCC's new precipitation climatology is compared to several other station-based precipitation climatologies as well as to precipitation climatologies derived from the GPCP V2.2 data set and from ECMWF's model reanalyses ERA-40 and ERA-Interim. Finally, how GPCC's best estimate for terrestrial mean precipitation derived from the precipitation climatology of 786 mm per year (equivalent to a water transport of 117,000 km³) is fitting into the global water cycle context is discussed.  相似文献   

Impact of rock-water interactions and recharge on water resources quality of the Agadir-Essaouira basin,southwestern Morocco     

Al Yacoubi Latifa  Bouchaou Lhoussaine  Jaillard Etienne  Masrour Moussa  Ait Brahim Yassine  El Mouden Ahmed  Schneider Jana  Reichert Barbara 《Arabian Journal of Geosciences》2017,10(7):169

The Agadir-Essaouira area in the occidental High Atlas Mountains of Morocco is characterized by a semi-arid climate. The scarcity and quality of water resources, exacerbated by long drought periods, constitute a major problem for a sustainable development of this region. Groundwater resources of carbonate units within Jurassic and Cretaceous aquifers are requested for drinking and irrigation purposes. In this study, we collected 84 samples from wells, boreholes, springs, and rivers. Hydrochemical and isotopic data were used to examine the mineralization and origin of water, which control groundwater quality. The chemical composition of water seems to be controlled by water-rock interactions, such as dissolution of carbonates (calcite and dolomite), weathering of gypsum, as well as ion exchange processes, which explain the observed variability. Stable isotopes results show that groundwater from the mainly marly Cretaceous aquifer are submitted to an evaporation effect, while samples from the chiefly calcareous Jurassic aquifer indicate a meteoric origin, due to a rapid infiltration of recharge runoff through the karstic outcrops. The low values of δ¹⁸O and δ²H suggest a local recharge from areas with elevations ranging from 400 to 1200 m for the Cretaceous aquifer and from 800 to 1500 m for the Jurassic units.  相似文献   

Could CoRoT-7b and Kepler-10b be remnants of evaporated gas or ice giants?     

Leitzinger M  Odert P  Kulikov YN  Lammer H  Wuchterl G  Penz T  Guarcello MG  Micela G  Khodachenko ML  Weingrill J  Hanslmeier A  Biernat HK  Schneider J 《Planetary and Space Science》2011,59(13):1472-1481

We present thermal mass loss calculations over evolutionary time scales for the investigation if the smallest transiting rocky exoplanets CoRoT-7b (∼1.68R_Earth) and Kepler-10b (∼1.416R_Earth) could be remnants of an initially more massive hydrogen-rich gas giant or a hot Neptune-class exoplanet. We apply a thermal mass loss formula which yields results that are comparable to hydrodynamic loss models. Our approach considers the effect of the Roche lobe, realistic heating efficiencies and a radius scaling law derived from observations of hot Jupiters. We study the influence of the mean planetary density on the thermal mass loss by placing hypothetical exoplanets with the characteristics of Jupiter, Saturn, Neptune, and Uranus to the orbital location of CoRoT-7b at 0.017 AU and Kepler-10b at 0.01684 AU and assuming that these planets orbit a K- or G-type host star. Our findings indicate that hydrogen-rich gas giants within the mass domain of Saturn or Jupiter cannot thermally lose such an amount of mass that CoRoT-7b and Kepler-10b would result in a rocky residue. Moreover, our calculations show that the present time mass of both rocky exoplanets can be neither a result of evaporation of a hydrogen envelope of a “Hot Neptune” nor a “Hot Uranus”-class object. Depending on the initial density and mass, these planets most likely were always rocky planets which could lose a thin hydrogen envelope, but not cores of thermally evaporated initially much more massive and larger objects.  相似文献