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31.
I. V. Kudryavtsev D. M. Volobuev V. A. Dergachev Yu. A. Nagovitsyn M. G. Ogurtsov 《Geomagnetism and Aeronomy》2016,56(7):858-862
Data on the content of the 14C cosmogenic isotope in tree rings, which were obtained as a result of laboratory measurements, are often used when solar activity (SA) is reconstructed for previous epochs, in which direct observations are absent. However, these data contain information not only about SA variations but also about changes in the Earth climatic parameters, such as the global temperature and the CO2 content in the Earth’s atmosphere. The effect of these variations on the 14C isotope content in different natural reservoirs after the last glacial termination to the middle of the Holocene is considered. The global temperature and the CO2 content increased on this time interval. In this case the 14C absolute content in the atmosphere increased on this time interval, even though the 14С to 12С isotope concentration ratio (as described by the Δ14С parameter) decreased. These variations in the radiocarbon absolute content can be caused by its redistribution between natural reservoirs. It has been indicated that such a redistribution is possible only when the rate of carbon exchange between the ocean and atmosphere depends on temperature. The values of the corresponding temperature coefficient for the 17–10 ka BC time interval, which make it possible to describe the carbon redistribution between the ocean and atmosphere, have been obtained. 相似文献
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O. M. Raspopov E. V. Lopatin T. Kolström V. A. Dergachev P. B. Dmitriev H. -P. Kahle H. Spiecker 《Izvestiya Atmospheric and Oceanic Physics》2013,49(8):799-811
Spectral analysis of tree ring data sets of Siberian spruce (Picea obovata) and Scots pine (Pinus sylvestris L.) was carried out to study the effects of climatic factors on the conifer tree radial growth in the territory of the Komi Republic. Analyses were performed for different natural subzones in the Komi Republic: the forest-tundra transition zone and the northern, middle, and southern taiga. The results show that several groups of periodicities can be found in the tree radial growth. One from groups of periodicities is related to internal processes in the atmosphere-ocean system; the other is related to the fluctuations in solar activity. 相似文献
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O. M. Raspopov V. A. Dergachev G. I. Zaitseva M. G. Ogurtsov 《Geomagnetism and Aeronomy》2013,53(8):917-921
It is shown that, over the past ~10000 years (the Holocene), deep Maunder type solar minima have been accompanied by sharp climate changes. These minima occurred every 2300–2400 years. It has been established experimentally that, at ca 4.0 ka BP, there occurred a global change in the structure of atmospheric circulation, which coincided in time with the discharge of glacial masses from Greenland to North Atlantic and a solar activity minimum. The climate changes that took place at ca 4.0 ka BP and the deep solar activity minimum that occurred at ca 2.5 ka BP affected the development of human society, leading to the degradation and destruction of a number of ancient civilizations. 相似文献
34.
O.M. Raspopov V.A. Dergachev M.G. Ogurtsov T. Kolström H. Jungner P.B. Dmitriev 《Journal of Atmospheric and Solar》2011,73(2-3):388-399
Unique palaeoclimatic data with annual time resolution as tree ring widths and annual varve deposits are analyzed in order to reveal periodicities in climatic processes at tens to hundreds of million years ago. The climatic periodicities thus found are compared with the solar and climatic periodicities observed at present. 相似文献
35.
Phanerozoic volcanic-associated massive sulfide deposits (VMSD) were subdivided into the Kuroko, Besshi, Cyprus, and Ural types, which differ in their ore geochemistry and mineralogy, in their composition of volcanic ore-hosting rock associations, and in the proportions of felsic and basaltic volcanics and sedimentary rocks in the volcanic successions. The earliest deposits that can be reliably attributed to the above types originated during the Neoproterozoic during the Pangea supercontinental cycle. Archean and Paleoproterozoic VMSD can be accepted as analogues of these types, resembling them in many respects, although differing from the classic deposits of these types in some characteristics. The formation history of Cyprus-type VMSD is traceable to the Paleoproterozoic when deposits in the Outocumpu area dated at approximately 1970 Ma originated during the early stage of Pangea-I amalgamation, whereas the most ancient Besshi-type deposits 1440 million years old originated during the breakup of that supercontinent. Most of the Neoarchean and Paleoproterozoic VMSD are similar in some of their principal features to those of the Ural and Kuroko types. Deposits of both these types and their ancient analogues evolved in the process of the Earth’s evolution and demonstrated unidirectional changes in their ore composition. 相似文献
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Geomagnetism and Aeronomy - A study of glacial−interglacial periods shows that, once ice sheets reach a critical maximal mass, the glaciation period changes to an interglacial one; the latter... 相似文献
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S. S. Vasiliev V. A. Dergachev O. M. Raspopov H. Jungner 《Geomagnetism and Aeronomy》2012,52(1):121-128
A spectral analysis of data on the flux of cosmogenic 10Be in ice core samples from the Central Greenland (project GRIP) over the last 10 thousand years have been carried out. It
has been shown that the 10Be flux varies cyclically; the most significant cycle is of about 2300 years. Variations in the position of the virtual geomagnetic
pole over 8000 years have been analyzed. Significant components, pointing to the cyclic variation in the position of the geomagnetic
pole with a period of about 2300 years, have been revealed in a periodogram of the virtual geomagnetic pole longitude. In
addition to the nearly 2300-year-long cycle, some lines are observable in the 10Be flux periodogram, which can be considered as a manifestation of the 1000-year-long cycle of the 10Be deposition rate on the ice surface. The relationship between the cyclicity of the geomagnetic pole position and the 10Be flux is discussed. 相似文献
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Geomagnetism and Aeronomy - The causes of climatic effects associated with a change in orbital parameters at decennial–centennial scales are still being debated in the scientific community.... 相似文献