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51.
Buylaert, J.‐P., Huot, S., Murray, A.S. & Van den haute, P.: Infrared stimulated luminescence dating of an Eemian (MIS 5e) site in Denmark using K‐feldspar. Boreas, 10.1111/j.1502‐3885.2010.00156.x. ISSN 0300‐9483. Infrared stimulated luminescence (IRSL) dating of K‐feldspars may be an alternative to quartz optically stimulated luminescence (OSL) dating when the quartz OSL signal is too close to saturation or when the quartz luminescence characteristics are unsuitable. In this paper, Eemian (MIS 5e) coastal marine sands exposed in a cliff section on the coast of southern Jutland (Denmark) are used to test the accuracy and precision of IRSL dating using K‐feldspars. This material has been used previously to test quartz OSL dating ( Murray & Funder 2003 ): a small systematic underestimation of <10% compared to the expected age of ~130 ka was reported. In our study, a single‐aliquot regenerative‐dose (SAR) IRSL protocol is used to determine values of equivalent dose (De) and the corresponding fading rates (g values). A significant age underestimation (of up to ~35%) is observed; this is attributed to anomalous fading. Using a single site‐average fading rate of 3.66 ± 0.09%/decade to correct the IRSL ages for all samples provides good agreement between the average fading‐corrected K‐feldspar age (119 ± 6 ka) and the independent age control (132–125 ka). This is despite the reservations of Huntley & Lamothe (2001) that their fading correction method is not expected to work on samples older than ~20–50 ka. This fading‐corrected feldspar result is not significantly different from the overall revised quartz age (114 ± 7 ka) also presented here. We conclude that fading‐corrected IRSL ages measured using K‐feldspar may be both precise and accurate over a greater age range than might be otherwise expected.  相似文献   
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The imminent return of the Genesis Sample Return Capsule (SRC) from the Earth’s L1 point on September 8, 2004, represents the first opportunity since the Apollo era to study the atmospheric entry of a meter-sized body at or above the Earth’s escape speed. Until now, reentry heating models are based on only one successful reentry with an instrumented vehicle at higher than escape speed, the 22 May 1965 NASA “FIRE 2” experiment. In preparation of an instrumented airborne and ground-based observing campaign, we examined the expected bolide radiation for the reentry of the Genesis SRC. We find that the expected emission spectrum consists mostly of blackbody emission from the SRC surface (T∼ ∼2630 K@peak heating), slightly skewed in shape because of a range of surface temperatures. At high enough spectral resolution, shock emission from nitrogen and oxygen atoms, as well as the first positive and first negative bands of N2+, will stand out above this continuum. Carbon atom lines and the 389-nm CN band emission may also be detected, as well as the mid-IR 4.6-μm CO band. The ablation rate can be studied from the signature of trace sodium in the heat shield material, calibrated by the total amount of matter lost from the recovered shield. A pristine collection of the heat shield would also permit the sampling of products of ablation.  相似文献   
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This article describes the development and performance of an integrated optical sensor system that has been designed for rapid analysis of split sediment cores. The primary aim of the system is to obtain information based on optically stimulated luminescence (OSL) techniques; these provide a record of the accrued radiation dose of material since deposition. Particularly after suitable normalization, the luminescence signal recorded along the length of the core will provide information on the relative age of the sediment. Two wavelengths of stimulation are used (infra-red and green) and these probe the feldspar, and combined feldspar and quartz components of the sediment respectively; the ratio of the two signals can thus provide some indication of relative changes in the silicate mineralogy. A secondary use of the system is for optical reflectance measurements. With the addition of a monochromator, optical reflectance spectroscopy can be applied to obtain additional information on down-core mineralogical changes. In this article we describe technical aspects of the sensor system, discuss measurement techniques and consider the relevance of data obtained. Two examples of sediment cores are presented, which demonstrate the applicability of the instrument.  相似文献   
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Geology in the Falkland Islands   总被引:2,自引:0,他引:2  
In the next few years we are likely to hear and learn much about the offshore geology of the Falkland Islands as exploratory drilling for hydrocarbons begins. The offshore geology may become better known than the onshore, of which there has been little detailed investigation in the 200+ years since settlements were established. Here we outline the history of geological investigations and present information gathered during recent fieldwork.  相似文献   
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