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Loss on ignition: a qualitative or quantitative method for organic matter and carbonate mineral content in sediments? 总被引:5,自引:7,他引:5
Juan I. Santisteban Rosa Mediavilla Enrique López-Pamo Cristino J. Dabrio M. Blanca Ruiz Zapata M. José Gil García Silvino Castaño Pedro E. Martínez-Alfaro 《Journal of Paleolimnology》2004,32(3):287-299
Since the publication of the paper of , loss on ignition (LOI) has been widely used as a method to estimate the amount of organic matter and carbonate mineral content (and indirectly of organic and inorganic carbon) in sediments. The relationships between LOI at 550 °C (LOI550) and organic carbon (OC) content and between LOI at 950 °C (LOI950) and inorganic carbon (IC) content are currently accepted as a standard. However, the comparison of 150 analyses of samples of diverse lithologies, collected from a single core, reveals that these relationships are affected by sediment composition (presence of clays, salts, and the variable content of organic carbon). This results in an incremental error on the estimation of carbon content from LOI values that invalidates the use of LOI values as a quantitative method for estimating carbon content. Conversely, the general trends of LOI550 and LOI950 show a good correlation with carbon content (both organic and inorganic) allowing use of LOI as a qualitative test for carbon content. Similarly, in our case, LOI at 105 °C (LOI105) is a good qualitative proxy for the trends in gypsum content. 相似文献
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B. Garcia-Lorenzo E. Mediavilla S. Arribas C. Del Burgo 《Astrophysics and Space Science》1997,248(1-2):43-49
We present the velocity field of the stars in the central 25″ × 22″ of NGC 1068 derived from 2-D spectroscopy of the Ca II
triplet. A preliminary analysis provides evidence for two distinct stellar systems in the centre of NGC 1068. In the outer
regions (say r > 10″), the mean stellar velocity field seems coupled to those of the ionized and molecular gas, indicating
aproximately regular rotation with the kinematic minor axis at PA ~ 0°. However, in the inner region, the stars are rotating,
whereas the ionized gas is outflowing in the NE-SW direction probably due to the effects of the nuclear activity, and the
molecular gas is responding to the bar potential.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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On the basis of the current knowledge about the size of the neutron, the nucleon-nucleon interaction, and the limit on the ratioGm/c
2
R<4/9 imposed by General Relativity, we find an upper limit of about 2M
, for stars of uniform density in the neutron phase. The importance of an accurate determination of the neutron radius for neutron stars studies is pointed out. 相似文献
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A. Ullán L. J. Goicoechea J. A. Muñoz E. Mediavilla M. Serra-Ricart E. Puga D. Alcalde A. Oscoz R. Barrena 《Monthly notices of the Royal Astronomical Society》2003,346(2):415-423
The Gravitational Lenses International Time Project (GLITP) collaboration observed the first gravitational lens system (QSO 0957+561) from 2000 February 3 to March 31. The daily VR observations were made with the 2.56-m Nordic Optical Telescope at Roque de los Muchachos Observatory, La Palma, Spain. We have derived detailed and robust VR light curves of the two components Q0957+561A and Q0957+561B. In spite of the excellent sampling rate, we have not found evidence in favour of true daily variability. With respect to variability on time-scales of several weeks, we measure VR gradients of about −0.8 mmag d−1 in Q0957+561A and +0.3 mmag d−1 in Q0957+561B. The gradients are very probably originated in the far source. Thus, adopting this reasonable hypothesis (intrinsic variability), we compare them to the expected gradients during the evolution of a compact supernova remnant at the redshift of the source quasar. The starburst scenario is roughly consistent with some former events, but the new gradients do not seem to be caused by supernova remnant activity. 相似文献
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Sebastin F. Snchez Begoa García-Lorenzo Knud Jahnke Evencio Mediavilla Jos Ignacio Gonzlez-Serrano Lise Christensen Lutz Wisotzki 《New Astronomy Reviews》2006,49(10-12):501
We have developed a new technique to decouple the spectra of the host and the nucleus of type I AGNs using integral field spectroscopy data. The technique is a simple extension of methods widely tested in 2D imaging. We present here the results from applying the technique to data taken with INTEGRAL at the 4.2 m William Herschel Telescope on the Seyfert 1 radio-galaxy 3C 120. We obtained, for the first time, a clean spectrum of the host galaxy, without contamination from the nuclear source. 相似文献
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We summarize the main conclusions derived from integral field spectroscopy, with optical fibres, of six Seyfert galaxies.
More than 95 spectra around the active nucleus have been obtained showing asymmetric emission-line profiles at different positions.
Continuum and emission-line intensity maps and ionized gas velocity fields have been derived for these six galaxies. We also
present the stellar velocity field for NGC 1068, NGC 3516 and NGC 985.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献