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581.
Olivier Jacquat Claire Rambeau Andreas Voegelin Natalia Efimenko André Villard Karl B. Föllmi Ruben Kretzschmar 《Swiss Journal of Geoscience》2011,104(3):409-424
In order to better understand the origin and enrichment mechanisms leading to elevated Zn concentrations in Jurassic limestone
of the Jura mountain range (JMR) and the Burgundy (B), we investigated four locations of Bajocian age (JMR: Lausen–Schleifenberg,
Gurnigel; B: Vergisson–Davayé, Lucy-le-Bois) and two locations of Oxfordian age (JMR: Dornach, Pichoux) for their Zn distribution
and speciation. Measurements of the acid-extractable and bulk Zn contents showed that Zn is stratigraphically and spatially
heterogeneously distributed, in association with permeable carbonate levels. Up to 3,580 and 207 mg/kg Zn was detected in
Bajocian and Oxfordian limestone, respectively, with numerous limestone samples having Zn contents above 50 mg/kg. Using X-ray
absorption near edge structure spectroscopy and micro-X-ray fluorescence spectrometry, the speciation and micro-scale distribution
of Zn was investigated for selected limestone samples. In Bajocian limestone sphalerite and/or Zn-substituted goethite and
a minor fraction of Zn-bearing carbonates were identified. In contrast, Zn-bearing carbonates (Zn-substituted calcite and
hydrozincite) were accounting for most of the total Zn in Oxfordian limestone. The micro-scale distribution of Zn for Bajocian
and Oxfordian limestone was however similar with localized Zn-rich zones in the limestone cement and at the rim of oolites.
The stratigraphic sporadicity and microscale heterogeneity of the Zn distribution together with the Zn speciation results
point to a hydrothermal origin of Zn. Occurence of Zn-goethite is probably linked to the oxidative transformation of framboidal
pyrite and hydrothermal sphalerite in contact with meteoritic waters. Difference in speciation between Bajocian limestone
and Oxfordian limestone may be related to differences in rock permeability and/or to various hydrothermal events. Isotopic
dating of the different mineralizations will be needed to decipher differences in Zn speciation and the precise chronology
of hydrothermal episodes. 相似文献
582.
Shaun Cole Will J. Percival John A. Peacock Peder Norberg Carlton M. Baugh Carlos S. Frenk Ivan Baldry Joss Bland-Hawthorn Terry Bridges Russell Cannon Matthew Colless Chris Collins Warrick Couch Nicholas J. G. Cross Gavin Dalton Vincent R. Eke Roberto De Propris Simon P. Driver George Efstathiou Richard S. Ellis Karl Glazebrook Carole Jackson Adrian Jenkins Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Bruce A. Peterson Will Sutherland Keith Taylor 《Monthly notices of the Royal Astronomical Society》2005,362(2):505-534
583.
Ignazio Ciufolini Erricos C. PavlisAntonio Paolozzi John RiesRolf Koenig Richard MatznerGiampiero Sindoni Karl Hans Neumayer 《New Astronomy》2012,17(3):341-346
In this paper we respond to the criticisms of “Phenomenology of the Lense-Thirring effect in the Solar System” by Iorio et al. about the general relativistic phenomena of gravitomagnetism and frame-dragging. The claims of the paper by Iorio et al. are not reproducible in any of our independent analyses. 相似文献
584.
The Zweikofel Formation of the Rattendorf Group in the Carnic Alps (Austria) is 95–102 m thick and consists of a cyclic succession of thin‐ to thick‐bedded fossiliferous limestone and intercalated thin intervals of siliciclastic sediment. The siliciclastic intervals were deposited in a shallow marine nearshore environment. The variety of carbonate facies indicates deposition in a shallow neritic, normal‐saline, low‐ to high‐energy environment. The Zweikofel Formation is characterized by a paracyclic vertical arrangement of facies and represents sedimentary sequences that are not well understood elsewhere in the Tethys. Fusulinids and conodonts from the upper Grenzland and Zweikofel formations in the Carnic Alps clearly suggest that what has been called ‘Sakmarian’ in the Tethys includes both the Sakmarian and Artinskian stages of the Global Time scale. Fusulinids from the lower part of the Zweikofel Formation at Zweikofel closely resemble those of the Grenzland Formation and approximately correlate with the upper part of the Sakmarian and lower part of the Artinskian of the Global Time scale. The upper part of the Zweikofel Formation correlates approximately with the lower‐middle (?) parts of the Artinskian Stage of the Global Time scale. A new regional Hermagorian Stage of the Tethyan scale is proposed between the Asselian and Yakhtashian. The lower boundary of the Hermagorian Stage is proposed to be located at the base of bed 81 in the 1015 section of Darvaz (Tadzhikistan). The boundary between the Hermagorian and Yakhtashian stages is placed at the base of bed 73 in the Zweikofel section at Zweikofel, Carnic Alps. In the Darvaz region, Tadzhikistan, the type area for the Yakhtashian Stage, this boundary has never been precisely defined. The entire fusulinid assemblage of the upper part of the Grenzland and Zweikofel formations reported herein includes 62 species of 18 genera, of which one subgenus and 12 species and subspecies are new. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
585.
Tore O. Vorren Karl‐Dag Vorren Odd Aasheim K. I. Torbjørn Dahlgren Matthias Forwick Kristian Hassel 《Boreas: An International Journal of Quaternary Research》2013,42(4):876-895
The stratigraphy of lake Endletvatn on northern Andøya, northern Norway, has been revisited to improve the understanding of the palaeoenvironment in the region during the Last Glacial Maximum (LGM). Four high‐quality cores were analysed with respect to various lithological parameters and macrofossil content, supplemented by 47 AMS radiocarbon dates. The sediments indicate a low‐energy environment with a mean sedimentation rate of 0.5 mm a?1. We infer perennially frozen ground in the surroundings during the LGM. Climate proxies indicate a high arctic climate (i.e. July mean temperatures between 0 and 3°C) throughout most of the LGM. The warmest periods are marked by a rise in seed, moss and animal fossils, and often also by higher organic production in the lake. These periods took place from 21.4 to 20.1, from 18.8 to 18.1, around 17 and from 16.4 cal. ka BP onwards. The shifts between the different climatic regimes occurred rapidly – probably during one or two decades. The present data do not support recently published conclusions stating that Picea, Pinus and Betula pubescens grew on Andøya during parts of the LGM. The highest relative sea level after the final deglaciation on northern Andøya is bracketed between 36 and 38 m a.s.l. It occurred between 21.0 and 20.3 cal. ka BP, peaking around 20.7 cal. ka BP. The final deglaciation of the northern tip of Andøya occurred 22.2 cal. ka BP. Then the western margin of the Andfjorden ice stream receded to the Kjølhaugen Moraine and shortly thereafter to the Endleten Moraine. Our research confirms that northern Andøya is a key location for understanding the natural environment in northwestern Europe during the LGM. 相似文献
586.
587.
Anette K. Mortensen Matthias Bigler Karl Grnvold Jrgen P. Steffensen Sigfús J. Johnsen 《第四纪科学杂志》2005,20(3):209-219
The tephrochronological record of the 1400–1640 m depth (~10 000–16 000 calendar ice core years before present) of the NGRIP ice core has been established by particle screening of selected samples. Ash was identified in 20 samples. Correlation with ice, marine and terrestrial records from volcanic source regions in the northern hemisphere positively identifies the Saksunarvatn Ash and the Vedde Ash (Ash Zone 1). Major element chemistry of the remaining identified ash layers mainly points towards an Icelandic origin. This tephrochronological record provides new important marker horizons for correlating the timing of the climatic changes associated with the Last Glacial Termination within the North Atlantic region, as well as outlining more details concerning the frequency and composition of volcanic eruptions occurring at this deglaciation. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
588.
Mars: a geologically active planet 总被引:1,自引:0,他引:1
Karl L Mitchell and Lionel Wilson summarize the case for martian geological activity in recent times. 相似文献
589.
The calibrations of the SORCE Total Irradiance Monitor (TIM) are detailed and compared against the designed uncertainty budget.
Several primary calibrations were accomplished in the laboratory before launch, including the aperture area, applied radiometer
power, and radiometer absorption efficiency. Other parameters are calibrated or tracked on orbit, including the electronic
servo system gain, the radiometer sensitivity to background thermal emission, and the degradation of radiometer efficiency.
The as-designed uncertainty budget is refined with knowledge from the on-orbit performance. 相似文献
590.
Nicholas Cross Simon P. Driver Warrick Couch Carlton M. Baugh Joss Bland-Hawthorn Terry Bridges Russell Cannon Shaun Cole Matthew Colless Chris Collins Gavin Dalton Kathryn Deeley Roberto De Propris George Efstathiou Richard S. Ellis Carlos S. Frenk Karl Glazebrook Carole Jackson Ofer Lahav Ian Lewis Stuart Lumsden Steve Maddox Darren Madgwick Stephen Moody Peder Norberg John A. Peacock Bruce A. Peterson Ian Price Mark Seaborne Will Sutherland Helen Tadros Keith Taylor 《Monthly notices of the Royal Astronomical Society》2001,324(4):825-841