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971.
Y. Quesnel W. Zylberman P. Rochette M. Uehara J. Gattacceca G. R. Osinski P. Dussouillez C. Lepaulard C. Champollion 《Meteoritics & planetary science》2020,55(3):480-495
In 2011, the discovery of shatter cones confirmed the 28 km diameter Tunnunik complex impact structure, Northwest Territories, Canada. This study presents the first results of ground‐based electromagnetic, gravimetric, and magnetic surveys over this impact structure. Its central area is characterized by a ~10 km wide negative gravity anomaly of about 3 mGal amplitude, roughly corresponding to the area of shatter cones, and associated with a positive magnetic field anomaly of ~120 nT amplitude and 3 km wavelength. The latter correlates well with the location of the deepest uplifted strata, an impact‐tilted Proterozoic dolomite layer of the Shaler Supergroup exposed near the center of the structure and intruded by dolerite dykes. Locally, electromagnetic field data unveil a conductive superficial formation which corresponds to an 80–100 m thick sand layer covering the impact structure. Based on the measurements of magnetic properties of rock samples, we model the source of the magnetic anomaly as the magnetic sediments of the Shaler Supergroup combined with a core of uplifted crystalline basement with enhanced magnetization. More classically, the low gravity signature is attributed to a reduction in density measured on the brecciated target rocks and to the isolated sand formations. However, the present‐day fractured zone does not extend deeper than ~1 km in our model, indicating a possible 1.5 km of erosion since the time of impact, about 430 Ma ago. 相似文献
972.
Astronomy Letters - Based on SDSS data, we consider the fraction of active galactic nuclei among polar-ring galaxies. We have found evidence for an excess of Seyfert galaxies and LINERS among... 相似文献
973.
Khamitov I. M. Bikmaev I. F. Burenin R. A. Glushkov M. V. Melnikov S. S. Lyapin A. R. 《Astronomy Letters》2020,46(1):1-11
Astronomy Letters - An example of simultaneous spectroscopic redshift measurements for a large number of galaxies in a cluster by multiobject spectroscopy with the medium- and low-resolution TFOSC... 相似文献
974.
Astronomy Letters - Based on an analysis of the dynamic spectra for solar flares in the meter wavelength range obtained with the ground-based Radio Solar Telescope Network, we consider the... 相似文献
975.
Natural Resources Research - Sand failure and production occurs when the formation stress exceeds the strength of the formation, which is derived majorly from the natural material that cements the... 相似文献
976.
977.
Izvestiya, Atmospheric and Oceanic Physics - We analyze our concepts about ocean dynamics and, in particular, internal waves. Our concepts have changed over the 50 years after the Polygon-70... 相似文献
978.
Yermakov A. N. Aloyan A. E. Arutyunyan V. O. 《Izvestiya Atmospheric and Oceanic Physics》2020,56(1):72-78
Izvestiya, Atmospheric and Oceanic Physics - The effect of ammonium sulfate ((NH4)2SO4) on the condensation of low-volatile organic compounds in atmospheric aerosol is considered. Using the UNIFAC... 相似文献
979.
Izvestiya, Atmospheric and Oceanic Physics - The minimum energy consumption in cities of the Russian Plain is largely determined by climatic conditions, because residential heating in winter is a... 相似文献
980.
Oceanology - A new area of oceanography, operational oceanography, involves a comprehensive assessment and forecast of the variability of the state of the marine environment. This requires... 相似文献