Modeling optical contrast for thin organic films on the sea surface     

K. A. Shmirko  O. G. Konstantinov  Yu. N. Kul’chin  S. Yu. Stolyarchuk  A. N. Pavlov  M. Yu. Korenskii 《Izvestiya Atmospheric and Oceanic Physics》2017,53(3):373-381

A continuation of the work dedicated to the study of slicks and film formations on the sea surface is presented. A vector model for the calculation of reflected radiation by the wavy sea surface with respect to the contribution of upwelling radiation from under the sea surface (the second type of waters) is described briefly in [5]. This work contains an analysis of numerical calculations according to the developed procedure and the search for optimal conditions of slick detection. The best conditions for detecting slicks on the sea surface are reached when a P-polarization component of reflected radiation is recorded. In this case, the value of contrast between a slick and a clean surface is 30% higher on average than in recording a contrast without using a polarization filter and is 50% higher than in the case of recording a contrast with a filter oriented to the maximum transmission of S polarization component of reflected radiation. It is shown that, under clear sky conditions, the optimal condition for recording slicks on a sea surface is videotaping in the plane of solar vertical at viewing angles sliding towards the sea surface and when a polarization filter that identifies the Р polarization component of sea radiation is used. In contrast, under overcast sky conditions, it is best to perform observations in the plane that has a wind velocity vector.  相似文献   

Geochronology and paleomagnetism of mafic igneous rocks in the Olenek Uplift, northern Siberia: Implications for Mesoproterozoic supercontinents and paleogeography     

Michael T.D. Wingate  Sergei A. Pisarevsky  Dmitry P. Gladkochub  Tatiana V. Donskaya  Konstantine M. Konstantinov  Anatoly M. Mazukabzov  Arkady M. Stanevich 《Precambrian Research》2009,170(3-4):256-266

We present a new, reliably dated Mesoproterozoic paleopole for Siberia, based on a combined geochronological and paleomagnetic study of mafic rocks within the Mesoproterozoic Sololi Group of the Olenek Uplift in northern Siberia. Ion microprobe (SHRIMP) U–Pb analysis yields crystallisation ages of 2036 ± 11 Ma for zircon from a basement granite and 1473 ± 24 Ma for baddeleyite from a large dolerite sill within the Kyutingde Formation. The baddeleyite result indicates that the lower Sololi Group is significantly older than was suggested by previous K–Ar results. Paleomagnetic analysis of the dolerite sill and related mafic intrusive rocks yields a paleopole at 33.6°N, 253.1°E, A₉₅ = 10.4°. A positive baked-contact test between the Kyutingde sill and sedimentary country rocks shows that the magnetisation is primary. Comparison of this paleopole with coeval results for Laurentia provides a revised reconstruction between Siberia and Laurentia, and implies that these two continents were parts of a single Mesoproterozoic supercontinent since at least 1473 Ma. We argue that Siberia, Laurentia, and Baltica belonged to the same supercontinent between 1473 Ma and mid-Neoproterozoic time.  相似文献   

Stage boundaries of the Triassic in Northeast Asia     

A. G. Konstantinov  T. V. Klets 《Stratigraphy and Geological Correlation》2009,17(2):173-191

The International Union of Geological Science approved the stage boundaries suggested by the international working groups for the Tethyan Triassic. In this work we estimate the possibility of their establishment and correlation in the Boreal sections of Northeast Asia, based on the analyzed distribution of ammonoids and conodonts. As the conodonts of the Induan Stage have not been identified for sure in the region under study, the lower boundary of the Triassic System is defined here at the base of the Otoceras concavum Zone of the ammonoid scale. In addition to the ammonoids Hedenstroemia hedenstroemi (Keyserling), the first occurrence of the conodonts Pseudogondolella nepalensis (Kozur et Mostler) is suggested to be the biomarker of the Olenekian Stage base. The lower boundaries of the Anisian and Ladinian stages, defined respectively at the basal levels of the Paracrochordiceras-Japonites Beds in Northern Dobrogea and the Eoprotrachyceras curionii Zone in the Brescian Prealps are recognizable, though with some reservations, at the base of the Grambergia taimyrensis and Eonathorstites oleshkoi zones in Northeast Asia. According to the priority principle and similarity between the ammonoid faunas of the Daxatina cf. canadensis Subzone and Frankites regoledanus Zone, the lower boundary of the Carnian Stage is defined at the base of the Alpine Trachyceras aon Zone. In Northeast Asia, this boundary is established at the base of the “Protrachyceras” omkutchanicum Zone, as we take into account the fact that the Daxatina and Stolleyites ammonoid genera occur in sections of British Columbia below the stratigraphic level of the Trachyceras forms. The lower boundary of the Norian Stage is concurrent with the base of the Guembelites jandianus Zone in the Alps and equivalent Stikinoceras kerri Zone in North America and Striatosirenites kinasovi Zone in Northeast Asia. The conodont species Norigondolella navicula (Huckriede) that is most important for the Boreal-Tethyan correlation cannot be used as a biomarker of the Norian lower boundary because of its problematic diagnosis and rare occurrence in the Boreal sections. The Rhaetian Stage base is defined at the appearance level of the Misikella conodont genus in the Hallstatt region, Austria, that is simultaneously the disappearance level of the characteristic Norian bivalves (Monotis) and ammonoids (Metasibirites). In Northeast Asia, this boundary is established at the top of the Monotis ochotica Zone. The correlation between the biostratigraphic units of the Middle-Upper Triassic conodont scale established in Northeast Asia and standard ammonoid zonation is verified.  相似文献   

Palaeomagnetic study of Vendian and Early Cambrian rocks of South Siberia and Central Mongolia: was the Siberian platform assembled at this time?   总被引：1，自引：0，他引：1  

V. A. Kravchinsky  K. M. Konstantinov  J. -P. Cogn 《Precambrian Research》2001,110(1-4)

A palaeomagnetic study of Vendian and Early Cambrian sediments from the Angara block of the Siberian platform: Shaman (52.08°N, 108.83°E) and Minya (58.0°N, 110.0°E) Formations, and the Tuva-Mongolian block: Tsagan-Olom and Bayan-Gol Formations (46.76°N, 96.37°E) isolated three different components of magnetization through thermal demagnetization. The stable high-temperature characteristic remanence directions show both normal and reverse polarities. The mean palaeopoles computed after these high-temperature components are: 32.0°S/71.1°E (dp/dm=6.9°/13.8°) for the Vendian Shaman Formation (10 sites, 80 samples), 33.7°S/37.2°E (dp/dm=8.6°/14.7°) for the Vendian Minya Formation (12 samples), 22.8°S/28.4°E (dp/dm=10.8°/21.6°) for the Vendian Tsagan-Olom Formation (4 sites, 25 samples) and 21.4°S/167.1°E (dp/dm=9.6°/19.1°) for the Early Cambrian Bayan-Gol Formation (6 sites, 49 samples). From a compilation of Vendian and Early Cambrian palaeopoles from the Anabar, Angara and Aldan blocks of the Siberian platform and Tuva-Mongolia block, we propose a model where these blocks were situated in an equatorial to low south palaeolatitude position, with their present-day southern boundaries facing the north pole. From the analysis of the scatter of these poles, we conclude that the Siberian platform might not have fully amalgamated by this time, and that significant rotations occurred after the Early Cambrian. Our new palaeopoles for the Tuva-Mongolia block, together with previously published ones, show that this block was already adjacent to Siberia by the Vendian and Early Cambrian. We propose that the large counterclockwise rotation of the Tuva-Mongolia block with respect to Angara block could mark the end of the closure of the part of the Palaeo-Asian ocean separating these two blocks, and could account for the occurrence of Vendian-Early Cambrian ophiolites in the region.  相似文献   

Computer Expert System for Epithermal Gold-Silver Deposit Prognostication (Okhotsk–Chuckchee Volcanic Belt,Northeast Russia)     

Strujkov  Sergey F.  Chizhova  Irina A.  Konstantinov  Michael M. 《Natural Resources Research》1999,8(4):315-343

The Okhotsk–Chuckchee volcanic belt (OCVB) represents a world class gold–silver province, being a well-studied part of the Circum-Pacific Rim. Extensive research, preceding the system compilation, included collection of various data on major gold–silver, silver–lead–zinc, and tin–silver ore fields (with some data on minor gold–quartz, gold–sulfide, and gold–rare-metal sites). The database consists of 129 ore fields of the OCVB and comprises 433 geological, mineralogical, geochemical, and geophysical indicators. Using the original pattern recognition programs (accounting the frequencies and correlation of the indicators), the most informative indicators were selected, their weights (both positive and negative) were identified, and an expert system (solution tree) was compiled. The computer system is intended to be an assistance to an expert in the ore field potential evaluation. The system includes several blocks of questions with a goal of classifying the geochemical type and size of the analyzed ore field. The questions have an indirect character, so they could be answered by an expert at early stages of exploration (before drilling). The level of recognition of sizes of the ore sites in the control populations is 95% or higher. The aim of the expert system is to reestimate a large number of known ore sites in a relatively brief period of time with the aid of the personal computer. The revealed patterns could be used in other less studied parts of the Circum-Pacific belt.  相似文献   

New Data on Geochronology of the Upper Quaternary Loess–Soil Series in the Terek–Kuma Lowland     

Sychev  N. V.  Konstantinov  E. A.  Zakharov  A. L.  Frechen  M.  Tsukamoto  S. 《Lithology and Mineral Resources》2022,57(4):336-347

Lithology and Mineral Resources - Drilling recovered the upper part (23 m) of the upland loess–paleosol series (LPS) on the right bank of the Kuma River near the Otkaznoe Settlement....  相似文献   

The Glaciolacustrine Terrace in the Izborsk-Malskaya Valley (the North-West of Russia): Composition,Age, and Origin     

Karpukhina  N. V.  Makkaveyev  A. N.  Zakharov  A. L.  Konstantinov  E. A.  Kurbanov  R. N.  Bricheva  S. S.  Sychev  N. V.  Baranov  D. V. 《Doklady Earth Sciences》2022,506(1):S73-S83

Doklady Earth Sciences - Studying the Izborsk-Malskaya Valley, the authors focus on the origin of glaciolacustrine terraces in overdeepened valleys widespread in the Late Valdai (Ostashkov,...  相似文献   

Response of permafrost landscapes of Central Yakutia to current changes of climate,and anthropogenic impacts     

A.N. Fedorov  P.Ya. Konstantinov 《Geography and Natural Resources》2009,30(2):146-150

We discuss the state of permafrost landscapes of Central Yakutia under the influence of current changes of climate and anthropogenic impacts. This study uses the data from the monitoring stations operated by the Permafrost Institute SB RAS, and from the Yakutsk and Pokrovsk meteorological stations. It is found that there is a rather good correlation between the data from the monitoring stations and from the Pokrovsk meteorological station. The last decade saw a considerable rise in temperatures of earth materials. The most sensitive to cliate change are the disturbed landscapes, primarily treeless landscapes such as anthropogenic complexes, and burned-out forests.  相似文献   

Geoarchaeological investigations at Studenoe,an Upper Paleolithic site in the Transbaikal Region,Russia     

Ian Buvit  Michael R. Waters  Mikhail V. Konstantinov  Aleksander V. Konstantinov 《Geoarchaeology》2003,18(6):649-673

In 1998, geoarchaeological research was carried out at the Upper Paleolithic site of Studenoe in the Transbaikal Region of Russia. The site is divided into three loci situated on two terraces overlooking the Chikoi River. Alluvial sediments beneath the oldest terrace (T₂) consist of two depositional units. Radiocarbon ages indicate that aggradation of the T₂ fill began before 18,000 yr B.P. Alluvial sediments beneath the lower terrace (T₁) range in age from 13,000 to 10,000 yr B.P. and are divided into three depositional units. Both terraces are overlain by Holocene colluvium. Archaeological materials at Studenoe 1/1, 1/2, and 2 include dwellings, hearths, and thousands of bone and stone artifacts assigned to the late Upper Paleolithic through the Bronze Age. Evidence of microblade technology is present in all components of the site. Material from recent excavations of Paleolithic levels in the T₂ fill at Studenoe includes mobiliary art, bone needles, and a large dwelling with four hearth features. © 2003 Wiley Periodicals, Inc.  相似文献   

Radionuclides in soils at the Semipalatinsk test site 40 years after excavation nuclear explosions     

E. V. Kvasnikova  S. K. Gordeev  S. V. Konstantinov 《Russian Meteorology and Hydrology》2008,33(1):27-33

Radionuclide composition of soils near craters produced by excavation explosions “1003” and “1004” in 1965 at the Semipalatinsk test site is characterized as of 2005. A conclusion is made that radionuclides ¹³⁷Cs, ¹⁵²Eu, ¹⁵⁴Eu, ¹⁵⁵Eu, ²⁴¹Am, and ⁶⁰Co do not penetrate deeper than the upper 2 cm of the chestnut solonetz-like soil. The patterns after the explosions studied can be traced over the terrain near the crater ejecta to present. Contamination levels rapidly decrease with the distance from the ground zero. It is demonstrated that technogenic soils in the region of nuclear tests in a dry-steppe zone can be a source of dust and secondary air contamination.  相似文献