Glacial-interglacial excursion in the concentration of atmospheric CO₂: effect in the ¹³C/¹²C ratio in wood cellulose     

R. V. KRISHNAMURTHY  S. EPSTEIN 《Tellus. Series B, Chemical and physical meteorology》1990,42(5):423-434

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Glacigenic deposits of the Central Deep: a key to the Late Quaternary evolution of the eastern Barents Sea   总被引：2，自引：0，他引：2  

VALERY GATAULLIN  LEONID POLYAK  OLEG EPSTEIN  BORIS ROMANYUK 《Boreas: An International Journal of Quaternary Research》1993,22(1):47-58

Sparker and shallow drilling data indicate that the Quaternary deposits in the Central Deep of the Barents Sea are mainly composed of glacigenic sediments. They comprise basal till and proximal and distal glaciomarine sediments deposited during the last glacial cycle. Apparent glaciotectonic features imply strong glacial erosion of Mesozoic bedrock. The general ice movement is assumed to have been from off Novaya Zemlya and it is concluded that the whole eastern Barents Sea was covered by the Late Weichselian ice-sheet.  相似文献   

O18/O16 Ratios in Rocks and Coexisting Minerals of the Skaergaard Intrusion, East Greenland     

TAYLOR  H. P.  Jr.; EPSTEIN  S. 《Journal of Petrology》1963,4(1):51-74

The Skaergaard intrusion of East Greenland is a gravitationallystratified gabbroic mass that has undergone extreme fractionalcrystallization. Oxygen-isotopic analyses have been obtainedfor the various rock types of this intrusion and for severalcoexisting minerals of these rocks. The general relationshipsamong the O¹⁸/O¹⁶ ratios of the minerals are the same as havebeen found for other igneous rocks, but the isotopic fracticnationsare smaller, probably as a result of the higher temperatureof formation of the Skaergaard rocks. The later differentiatesare progressively depleted in O¹⁸ to a marked degree relativeto the earlier-formed portions of the layered series; the late-stagegranophyres are 4–5 per mil lower in O¹⁸/O¹⁶ than thelayered Lower Zone gabbros, and are 7–9 per mil lowerthan normal granitic rocks from other localities. This progressivedepletion in O¹⁸ is a result of crystallization and settlingout of minerals that are, on the whole, about 1 per mil higherin O¹⁸/O¹⁶ than the magma liquid. Calculations based on a simplecrystallization model are in agreement with the experimentalresults.  相似文献   

Internal calibration device for the infrared imager of ISO     

SAINT-PÉ  O.  PUGET  P.  ROUAN  D.  EPSTEIN  G.  COMBES  M. 《Experimental Astronomy》1994,4(3-4):195-211

The imager of the infrared satellite ISO will allow spectral imaging under very low flux conditions in the two to-eighteen-microns range, close to the fundamental limit of the zodiacal background photon noise. To optimize the performance of the imager, we must use an internal calibration device, mainly to track changes in the responsivity of the pixels of the detectors arrays, the limit of detection greatly depending upon the quality of the flat field corrections in certain cases.The first section introduces ISO and its infrared imager and emphasizes the necessity of in-flight calibration. The following chapter presents the specifications for the internal calibration device. The chosen design for the flight model which consists of an infrared emitter and two integrating spheres, is presented in the third chapter. The last part describes the cryogenic bench dedicated to relative photometric tests, the absolute calibration is made in the camera. Endly we present the results obtained with this facility and final tests to achieve the qualification of the device.  相似文献