Biomorphic microstructures of ferromanganese stromatolites     

V. V. Avdonin  N. I. Yeryomin  E. A. Zhegallo  N. E. Sergeyeva 《Doklady Earth Sciences》2016,471(1):1131-1133

It was found as a result of detailed study of ferromanganese stromatolites that columnar formations, i.e., fossilized stratified bacterial tufts with rhythmically alternating layers of glycocalyx, accumulations of filamentous bacteria, and lens-shaped two-layered (alternation of homogeneous microlayers with porous ones containing filamentous bacteria trichomes) packages, serve as the basis for stromatolite buildup.  相似文献   

The Ozernoye meteorite: New data on mineralogy     

Yu. V. Erokhin  V. A. Koroteev  V. V. Khiller  E. V. Burlakov  K. S. Ivanov  D. A. Kleimenov 《Doklady Earth Sciences》2016,471(2):1273-1276

New data on the mineral composition of the Ozernoye meteorite, found in the Kurgan region in 1983, are presented. It has been found that that the meteorite’s matter is composed of olivine (chrysolite), orthopyroxene (bronzite), clinopyroxene (augite), maskelynite, chromite, ilmenite, metals Fe and Ni (kamasite, taenite), sulfides (troilite, pentlandite), chlorapatite, and merrillite. Augite, taenite, pentlandite, and merrillite were identified in the Ozernoye meteorite for the first time. The chemical compositions are given for all these minerals. The meteorite itself is an ordinary chondrite stone belonging to petrological type L5.  相似文献   

New data on the composition of jordanite–geocronite Pb–Sb–As sulfosalts at the Berezitovoe deposit (Upper Amur Region,Russia)     

A. S. Vakh  O. V. Avchenko  N. A. Goryachev  V. I. Gvozdev  A. A. Karabtsov 《Doklady Earth Sciences》2016,467(2):402-407

New data on the composition of jordanite–geocronite Pb–Sb–As sulfosalts in the vein–disseminated gold ore at the Berezitovoe deposit were provided. Within the studied quartz–sulfide sample, some grains of Pb–Sb–As sulfosalts, uniform in composition and azonal, are drastically different from each other in As and Sb contents forming a quasi-continuous range of solid compounds from jordanite to geocronite. Jordanite–geocronite minerals at the Berezitovoe deposit (relative to the Darasun deposit) are characterized by a higher Pb concentration with a low polymetal total. It is assumed that such typomorphic features of the composition of Pb–Sb–As sulfosalts are indicative of specific formation conditions of gold mineralization in polymetallic ores at the Berezitovoe deposit.  相似文献   

The area and absolute magnetic flux of sunspots over the past 400 years     

Yu. A. Nagovitsyn  A. G. Tlatov  E. Yu. Nagovitsyna 《Astronomy Reports》2016,60(9):831-838

A new series of yearly-mean relative sunspot numbers SN ₂ that has been extrapolated into the past (to 1610) is presented. The Kislovodsk series with the scale factor b = 1.0094 ± 0.0059 represents a reasonable continuation of the mean-monthly and mean-yearly total sunspot areas of the Greenwich series after 1976. The second maximum of the 24th solar-activity cycle was not anomalously low, and was no lower than 6 of the past 13 cycles. A series A ₂ of values for the total sunspot area in 1610–2015 has been constructed, and is complementary to new versions of the series of the relative number of sunspots SN ₂ and the number of sunspot groups GN ₂. When needed, this series can be reduced to yield a quantity having a clear physical meaning—the spot absolute magnetic flux Φ _Σ(t)[Mx] = 2.16 × 10¹⁹ A(t) [mvh]. The maximum sunspot area during the Maunder minimum is much higher in the new series compared to the previous version. This at least partially supports the validity of arguments that cast doubt on the anomalously low ampltude of the solar cycles during the Maunder minimum that has been assumed by many researchers earlier.  相似文献   

Middle Paleozoic kimberlite magmatism in the northeastern Siberian craton     

E. O. Egorova  V. P. Afanas’ev  N. P. Pokhilenko 《Doklady Earth Sciences》2016,470(2):1023-1026

The mineral chemistry and crystal morphology of kimberlite pyropes from the Billyakh River placer in the northeastern Siberian craton are characterised in terms of the placer history. The pyropes bear signatures of chemical weathering (dissolution), presumably in a Middle Paleozoic laterite profile, and therefore were originally hosted by Middle Paleozoic kimberlites. The broad occurrence of placer pyropes with lateritic dissolution signatures points to the presence of Middle Paleozoic diamond-bearing kimberlites in the study area.  相似文献   

In-bearing potential of tin‒sulfide mineralization in ore deposits of the Russian Far East     

G. G. Pavlova  A. G. Vladimirov  V. I. Gvozdev  P. G. Korostelev  B. I. Semenyak  V. G. Gonevchuk  P. A. Tishin 《Doklady Earth Sciences》2016,471(1):1118-1122

The increased demand for indium has made it necessary to revise prospects of In-bearing tin ore deposits in the Russian Far East on the basis of geological data and results of recent analytical methods (X-ray fluorescence with synchrotron radiation, atomic absorption, and ICP-MS). The average In contents in ores of the Tigrinoe and Pravourmiiskoe deposits vary from 55 to 70 ppm, which allows tin ore deposits with Sn?sulfide mineralization to be considered as quite promising with respect to In production from ores of Russian deposits. By their estimated In reserves, the Tigrinoe and Pravourmiiskoe deposits may be attributed to large ore objects.  相似文献   

Chemical composition,isotopic U–Pb age,and source of zircon from polymineralic ichet’yu occurrence,Mobile Timan     

A. B. Makeev  T. B. Bayanova  S. E. Borisovsky  O. M. Zhilicheva 《Geology of Ore Deposits》2016,58(8):646-652

This study focuses on the morphological features, color cathodoluminescence, chemical composition, age, and source of zircons from the Ichet’yu occurrence. The isotopic U–Pb age of Paleo–Mezoproterozoic zircon grains varies within an interval of ~700 Ma from 2247 to 1478 Ma. The average roundness and well-preserved integrity of zircon grains allow us to suggest their proximal source. The available data show that the basement of the Middle Timan, composed of continental Paleo–Mezoproterozoic igneous rocks, is the most probable source of zircon in the Ichet’yu occurrence. These rocks are apparently a continuation of the Archean–Proterozoic Arkhangel’sk Mobile Belt.  相似文献   

Abnormal composition of carbon isotopes in underground alkaline waters of Kuzbass     

S. L. Shvartsev  O. E. Lepokurova  V. A. Ponomarchuk  E. V. Domrocheva  D. A. Sizikov 《Doklady Earth Sciences》2016,469(2):877-881

The first data on abnormally high δ¹³С values in hydrocarbonates (НСО ₃^-) dissolved in underground waters of coal deposits of Kuzbass (up to +30.9‰) are reported. It is shown that such an unusual isotope composition of waters results from the long, strictly directed interaction in the water–rock–gas–organic material system occurring under the conditions of hindered water exchange. Extensive fractionation of C isotopes is the result of the evolution of the water–rock–gas–coal system after penetration of infiltration waters into the coal deposits and their long interaction with all these components, rather than metamorphism of organic material upon its transformation into coal. With respect to such an approach, the isotope composition of dissolved C may indicate the duration of the evolution in the water–rock–gas–organic material system.  相似文献   

Influence of long-period oscillations on the development of droughts in Northern Eurasia     

Semenov  V. A.  Chernokulskii  A. V.  Solomina  O. N. 《Doklady Earth Sciences》2016,471(1):1217-1220

Doklady Earth Sciences - Estimates of the influence of the Atlantic long-period oscillation (ALO) on the formation of droughts in Northern Eurasia were obtained using the results of numerical...  相似文献   

Ionospheric response to a rocket launch from the Vostochnyi Cosmodrome     

G. A. Zherebtsov  N. P. Perevalova 《Doklady Earth Sciences》2016,471(2):1280-1283

The atmospheric disturbances caused by the first rocket launch from the Vostochnyi Cosmodrome on April 28, 2016, were registered 10–24 min after the launch using the signals of the GPS/GLONASS global navigation satellite systems. The analysis of the spatial distribution of the disturbances allowed the conclusion that the launch vehicle moved northwest from the cosmodrome, which corresponds to a trajectory of the satellite movement to the orbit with an inclination of 98º.  相似文献