scholarly journals Lithochemical Stream Sediments of the Dukat Gold–Silver Ore-Forming System (North–East of Russia)

Minerals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 789
Author(s):  
Artem S. Makshakov ◽  
Raisa G. Kravtsova ◽  
Vasiliy V. Tatarinov

The composition, structure and formation features of the exogenous anomalous geochemical fields (AGFs) identified by lithochemical stream sediments (LSSs) are considered using the examples of the Dukat gold–silver ore-forming system and the deposit with the same name. The research was carried out in the Balygychan–Sugoy trough (Magadan region, north–east of Russia). Areal geochemical surveys on the 1:200,000 and 1:50,000 scales were conducted. Exogenous AGFs of basic element indicators of all known mineralization types were studied. It is shown that the surveys on the 1:200,000 scale are characterized by simplicity, relative depth and the possibility to obtain information operatively about the metallogeny of the area as a whole. At the same time, the anomalies were revealed as a result of surveys often making a relatively poor component composition and low contrast compared with ores. The violation of quantitative and sometimes qualitative relationships can be seen between elements, especially those related to gold–silver mineralization. In this situation, the most informative are surveys of LSSs on the 1:50,000 scale. The AGFs were revealed as a result of their performance to have a richer component composition and high contrast, conforming to different ore types. It is shown that, while prospecting for gold–silver mineralization with LSSs in cryolithogenesis zone conditions, the binding forms study of mineralization element indicators is effective. In watercourse heads, where alluvium is practically absent, mosses are proposed for sampling, as they hold the sandy silt material firmly. The obtained results are recommended for use at all stages of prospecting, not only in the north–east of Russia but also in other similar climatic regions.

Author(s):  
V. A. Stepanov ◽  

Information on the geological and isotopic age of the Kubaka gold-silver deposit in the Omolon middle massif in the North-East of Russia is presented. It has been established that the Kubaka deposit geological age lies in between the Late Devonian age of the Kedon series volcanites, containing the gold-silver mineralization, and the Early Carboniferous age of the Korbinsky suite terrigenous rocks, overlapping the volcanites and the mineralization. The post-ore nature of the Omolon complex dykes, which produce no significant impact on the distribution of gold mineralization in ore bodies, is shown. According to isotope dating, the following stages of the Kubaka deposit formation are distinguished: the accumulation of the Kubaka suite tuffs (369 Ma); the introduction of subvolcanic intrusions (344 and 337 Ma); the formation of ore metasomatites (335±5 Ma); the formation of gold-silver mineralization (330 and 334 - 324 Ma); the introduction of post-ore dikes (179±8 - 176±10 Ma).


2020 ◽  
Vol 9 (4) ◽  
pp. 142-148
Author(s):  
Nadezhda Vasilyevna Portnyagina ◽  
Vasiliy Vitalyevich Punegov ◽  
Elmira Elizbarovna Echishvili ◽  
Marina Gennadyevna Fomina ◽  
Ivan Vladimirovich Gruzdev

The paper presents the results of the research on the growth, development, and biochemical evaluation of introduced Pyrethrum majus plants in the middle taiga subzone of the Komi Republic. It is established that in the conditions of culture the species is characterized by a high stability and winter hardiness. The phenology and dynamics of plant growth were studied. Morphological parameters of vegetative and generative shoots were determined. The yield of essential oil from the aboveground phytomass of P. majus and its component composition were studied. It was found that the content of essential oil of flowering plants varied over the years of research from 0,25 to 1,41% and depended on the weather conditions of the growing season. More than 190 components were found in the essential oil of P. majus plants using the method of GLC analysis, 48 of them were identified. The main terpenoids in the essential oil were S-(+) carvone (5465%), -tuyon (610%), TRANS-and CIS-p-Menta-2,8-dienols (2,32,8%), 1,8-Cineol (1,42,9%), CIS Menta-1(7)8-Dien-2ol (1,52,1%), germacrene d (1,21,8%) -cadinol (0,51,5%), -muurolol (0,22,6%). It was found that the component composition of the essential oil from perennial plants P. majus corresponds to the carvone-Tuyon chemotype and did not change significantly due to the meteorological conditions of the environment. Taking into account a high adaptation of plants of this species to the conditions of the middle taiga subzone of the Komi Republic, high indicators of aboveground phytomass with a sufficient content of essential oil, P. majus can be successfully cultivated in the North as a promising spicy-aromatic medicinal and ornamental plant.


Antiquity ◽  
1976 ◽  
Vol 50 (200) ◽  
pp. 216-222
Author(s):  
Beatrice De Cardi

Ras a1 Khaimah is the most northerly of the seven states comprising the United Arab Emirates and its Ruler, H. H. Sheikh Saqr bin Mohammad al-Qasimi, is keenly interested in the history of the state and its people. Survey carried out there jointly with Dr D. B. Doe in 1968 had focused attention on the site of JuIfar which lies just north of the present town of Ras a1 Khaimah (de Cardi, 1971, 230-2). Julfar was in existence in Abbasid times and its importance as an entrep6t during the sixteenth and seventeenth centuries-the Portuguese Period-is reflected by the quantity and variety of imported wares to be found among the ruins of the city. Most of the sites discovered during the survey dated from that period but a group of cairns near Ghalilah and some long gabled graves in the Shimal area to the north-east of the date-groves behind Ras a1 Khaimah (map, FIG. I) clearly represented a more distant past.


1999 ◽  
Vol 110 (5-6) ◽  
pp. 455-463 ◽  
Author(s):  
S. Güvenç ◽  
Ş Öztürk
Keyword(s):  

Author(s):  
Valentina Tagliapietra ◽  
Flavia Riccardo ◽  
Giovanni Rezza

Italy is considered a low incidence country for tick-borne encephalitis (TBE) in Europe. Areas at higher risk for TBE in Italy are geographically clustered in the forested and mountainous regions and provinces in the north east part of the country, as suggested by TBE case series published over the last decade.


Italy is considered a low-incidence country for tick-borne encephalitis (TBE) in Europe.1 Areas at higher risk for TBE in Italy are geographically clustered in the forested and mountainous regions and provinces in the north east part of the country, as suggested by TBE case series published over the last decade.2-5 A national enhanced surveillance system for TBE has been established since 2017.6 Before this, information on the occurrence of TBE cases at the national level in Italy was lacking. Both incidence rates and the geographical distribution of the disease were mostly inferred from endemic areas where surveillance was already in place, ad hoc studies and international literature.1


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