Metasomatism and ore formation at contacts of dolerite with saliferous rocks in the sedimentary cover of the southern Siberian platform

2007 ◽  
Vol 49 (4) ◽  
pp. 271-284 ◽  
Author(s):  
M. P. Mazurov ◽  
S. N. Grishina ◽  
V. E. Istomin ◽  
A. T. Titov
Minerals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 354
Author(s):  
Anatoly M. Sazonov ◽  
Aleksei E. Romanovsky ◽  
Igor F. Gertner ◽  
Elena A. Zvyagina ◽  
Tatyana S. Krasnova ◽  
...  

The gold and platinum-group elements (PGE) mineralization of the Guli and Kresty intrusions was formed in the process of polyphase magmatism of the central type during the Permian and Triassic age. It is suggested that native osmium and iridium crystal nuclei were formed in the mantle at earlier high-temperature events of magma generation of the mantle substratum in the interval of 765–545 Ma and were brought by meimechite melts to the area of development of magmatic bodies. The pulsating magmatism of the later phases assisted in particle enlargement. Native gold was crystallized at a temperature of 415–200 °C at the hydrothermal-metasomatic stages of the meimechite, melilite, foidolite and carbonatite magmatism. The association of minerals of precious metals with oily, resinous and asphaltene bitumen testifies to the genetic relation of the mineralization to carbonaceous metasomatism. Identifying the carbonaceous gold and platinoid ore formation associated genetically with the parental formation of ultramafic, alkaline rocks and carbonatites is suggested.


2021 ◽  
Vol 62 (03) ◽  
pp. 377-387
Author(s):  
B.B. Kochnev ◽  
A.B. Kuznetsov ◽  
D.R. Sitkina ◽  
A.Yu. Kramchaninov

Abstract —The least altered limestones of the Ukta and Eselekh formations in the Precambrian section of the Kharaulakh uplift have a minimum 87Sr/86Sr ratio of 0.70673–0.70715. The lowest 87Sr/86Sr ratio of the overlying Neleger and Sietachan formations is 0.70791–0.70817. Based on these data, along with the earlier obtained positive δ13С values (up to 8‰) for the Kharaulakh section, we have estimated the age of the Ukta and Eselekh formations at 800–670 Ma and the age of the Neleger and Sietachan formations at ~640–580 Ma. The Pb–Pb isochron age of the least altered limestones of the Eselekh Formation calculated from eight samples is 720 ± 30 Ma. This age permits us to define the lower part of the Kharaulakh section of the Ukta and Eselekh formations to be the late Tonian of the International Chronostratigraphic Chart or to the Upper Riphean of the General Stratigraphic Scale of Russia. The presence of reliably dated Upper Riphean sediments in the Kharaulakh uplift indicates a more complex structure of the Precambrian sedimentary cover on the Arctic margin of the Siberian Platform than assumed earlier.


2021 ◽  
Author(s):  
Tatyana Bagdasaryan ◽  
Roman Veselovskiy ◽  
Viktor Zaitsev ◽  
Anton Latyshev

<p>The largest continental igneous province, the Siberian Traps, was formed within the Siberian platform at the Paleozoic-Mesozoic boundary, ca. 252 million years ago. Despite the continuous and extensive investigation of the duration and rate of trap magmatism on the Siberian platform, these questions are still debated. Moreover, the post-Paleozoic thermal history of the Siberian platform is almost unknown. This study aims to reconstruct the thermal history of the Siberian platform during the last 250 Myr using the low-temperature thermochronometry. We have studied intrusive complexes from different parts of the Siberian platform, such as the Kotuy dike, the Odikhincha, Magan and Essey ultrabasic alkaline massifs, the Norilsk-1 and Kontayskaya intrusions, and the Padunsky sill. We use apatite fission-track (AFT) thermochronology to assess the time since the rocks were cooled below 110℃. Obtained AFT ages (207-173 Ma) are much younger than available U-Pb and Ar/Ar ages of the traps. This pattern might be interpreted as a long cooling of the studied rocks after their emplacement ca. 250 Ma, but this looks quite unlikely because contradicts to the geological observations. Most likely, the rocks were buried under a thick volcanic-sedimentary cover and then exhumed and cooled below 110℃ ca. 207-173 Ma. Considering the increased geothermal gradient up to 50℃/km at that times, we can estimate the thickness of the removed overlying volcanic-sedimentary cover up to 207-173 Ma as about 2-3 km.</p><p>The research was carried out with the support of RFBR (grants 20-35-90066, 18-35-20058, 18-05-00590 and 18-05-70094) and the Program of development of Lomonosov Moscow State University.</p>


2020 ◽  
Vol 11 (1) ◽  
pp. 75-87
Author(s):  
M. S. Myshenkova ◽  
V. A. Zaitsev ◽  
S. Thomson ◽  
A. V. Latyshev ◽  
V. S. Zakharov ◽  
...  

We present the first results of fission-track dating of apatite monofractions from two rock samples taken from the Southern carbonatite massif of the world’s largest alkaline ultrabasic Guli pluton (~250 Ma), located within the Maymecha-Kotuy region of the Siberain Traps. Based on the apatite fission-track data and computer modeling, we propose two alternative model of the Guli pluton's tectonothermal history. The models suggest (1) rapid post-magmatic cooling of the studied rocks in hypabyssal conditions at depth about 1.5 km, or (2) their burial under a 2-3 km thick volcano-sedimentary cover and reheating above 110°C, followed by uplift and exhumation ca. 218 Ma.


2020 ◽  
pp. 68-84
Author(s):  
S. M. Makeev ◽  
E. A. Muromtsev ◽  
V. A. Makarov ◽  
G. V. Belokonov

Information collected on deposits, ore occurrences, and lead and zinc mineralization points known within the Yenisei Ridge is provided. A summary of the latest data on the geology and metallogeny of lead and zinc in the region is presented. A brief description of the deposits is given and their ore formation typification is carried out. The position of deposits in a stratigraphic section, the relationship with geological formations and tectonic structures, and subsequent conclusions about deposit location patterns and metallogenic zonality of the area were examined. The position analysis of polymetallic mineralization in regional geophysical and geochemical field revealed the presence of lead → zinc → barium trend from the Ishimbinsk fault towards the Siberian platform and the potential discovery of economically significant polymetallic mineralization in the eastern Yenisei Ridge.


Lithosphere ◽  
2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Xunyu Hu ◽  
Xiaohui Li ◽  
Feng Yuan ◽  
Simon M. Jowitt ◽  
Alison Ord ◽  
...  

Abstract Recent exploration has identified a series of Cu-Mo skarn deposits within the Xuancheng-Magushan orefield. The orefield forms part of the Nanling-Xuancheng mining district, which is located within the Middle-Lower Yangtze River Metallogenic Belt (MLYRMB) of central-eastern China. However, this area contains thick and widespread unprospective sedimentary cover sequences that have impeded traditional approaches to mineral exploration. This study presents the results of 3D numerical simulation modeling that identifies possible mineral exploration targets within the entire Xuancheng-Magushan orefield. This modeling enables the identification of unexplored areas with significant exploration potential that are covered by thick sedimentary sequences that cannot be easily explored using traditional exploration approaches. This study outlines the practical value of 3D numerical simulation-based targeting in areas with thick sedimentary cover sequences and uses the Flac3D software package to couple processes involved in ore formation such as stress, pressure, and heat transfer. Here, we use volumetric strain increments calculated during numerical modeling as the thermodynamic representation of the generation of space during prograde skarn formation, with this space filed by sulfides either penecontemporaneously or soon after magmatism. This process occurred during retrograde hydrothermal ore formation and the genesis of the skarn-type mineralization in this area. The results of the volumetric strain increment calculated during this numerical modeling study matches the distribution of known mineralization as well as delineating eight potential targets that have not yet been explored but represent areas of significant exploration potential within the Xuancheng-Magushan orefield, indicating these targets should be considered prospective for future mineral exploration. One of these targets was also identified during our previous Comsol-based numerical modeling of the formation of the Magushan Cu-Mo skarn deposit. The fact that this area has been identified as prospective using two different numerical modeling methods indicates that this area should be prioritized for future exploration and also validates the numerical modeling approaches used here and in our previous research that more specifically focused on the Magushan skarn deposit. Overall, our study indicates that prospectivity modeling using 3D numerical simulation-based approaches can be both effective and economical and should be considered an additional tool for future mineral exploration to reduce exploration risks when targeting mineralization in areas with thick and unprospective sedimentary cover sequences.


2020 ◽  
Vol 15 (4) ◽  
Author(s):  
V.A. Kontorovich ◽  
◽  
A.Yu. Kalinin ◽  
L.M. Kalinina ◽  
M.V. Solov'ev ◽  
...  

The work is devoted to the analysis of the geological structure of the northern continental margin of the Siberian Platform and the western part of the Laptev Sea. In terms petroleum geological zoning, the study area covers the Anabar-Khatanga and Lena-Anabar petroleum bearing areas of the Lena-Tunguska petroleum province and the West Laptev Sea promising petroleum province. Seismogeological models of sedimentary stratum on the continent and in the water area are considered; the conclusion was made that the Northern Siberian and Laptev Sea basins are separated by a large basement high that extends from the Taimyr Peninsula along the coastline to the Lena River issue. A complex analysis of geological and geophysical data made it possible to conclude that the most probable model is that the western part of the Laptev Sea is a continuation of the Siberian Platform with an Archaean-Proterozoic basement and an Upper Proterozoic-Phanerozoic sedimentary cover.


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