Phosphorus in alkali feldspars as an indicator for prospecting for pegmatite-type rare-metal ore deposits in Altay, NW China

2013 ◽  
Vol 13 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Tang Yong ◽  
Zhang Hui ◽  
Su Guizhen
2019 ◽  
Vol 10 (2) ◽  
pp. 375-404 ◽  
Author(s):  
N. G. Murzintsev ◽  
I. Yu. Annikova ◽  
A. V. Travin ◽  
A. G. Vladimirov ◽  
B. A. Dyachkov ◽  
...  

The article presents an event correlation of the Permian‐Triassic granites of the Altai collision system, which are associated with industrial ore deposits and occurrences (Mo‐W, Sn‐W, Li‐Ta‐Be). The multi‐system and multi‐mineral isotope datings of igneous rocks and ore bodies (U/Pb, Re/Os, Rb/Sr, Ar/Ar‐methods) suggest the postcollisional (intraplate) formation of ore‐magmatic systems (OMS), the duration of which depended on the crustmantle interaction and the rates of tectonic exposure of geoblocks to the upper crustal levels.Two cases of the OMS thermal history are described: (1) Kalguty Mo‐W deposit associated with rare‐metal granite‐leucogranites and ongonite‐ elvan dykes, and (2) Novo‐Akhmirov Li‐Ta deposit represented by topaz‐zinnwaldite granites and the contemporary lamprophyre and ongonit‐elvan dykes. For these geological objects, numerical modeling was carried out. The proposed models show thermal cooling of the deep magmatic chambers of granite composition, resulting in the residual foci of rare‐metal‐granite melts, which are known as the petrological indicators of industrial ore deposits (Mo‐W, Sn‐W, Li‐Ta‐Be). According to the simulation results concerning the framework of a closed magmatic system with a complex multistage development history, the magmatic chamber has a lower underlying observable massif and a reservoir associated with it. A long‐term magmatic differentiation of the parental melt (a source of rare‐metal‐granite melts and ore hydrothermal fluids) takes place in this reservoir.


2015 ◽  
Vol 27 (3) ◽  
pp. 433-457 ◽  
Author(s):  
Qifeng Zhou ◽  
Kezhang Qin ◽  
Dongmei Tang ◽  
Chunlong Wang ◽  
Ye Tian ◽  
...  
Keyword(s):  

Minerals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1166
Author(s):  
Leonid A. Neymark ◽  
Anatoly M. Larin ◽  
Richard J. Moscati

This paper investigates applicability of cassiterite to dating ore deposits in a wide age range. We report in situ LA-ICPMS U-Pb and Pb-Pb dating results (n = 15) of cassiterite from six ore deposits in Russia ranging in age from ~1.85 Ga to 93 Ma. The two oldest deposits dated at ~1.83–1.86 Ga are rare metal Vishnyakovskoe located in the East Sayan pegmatite belt and tin deposits within the Tuyukan ore region in the Baikal folded region. Rare metal skarn deposits of Pitkäranta ore field in the Ladoga region, Fennoscandian Shield are dated at ~1.54 Ga. Cassiterite from the Mokhovoe porphyry tin deposit located in western Transbaikalia is 810 ± 20 Ma. The youngest cassiterite was dated from the deposits Valkumei (Russian North East, 108 ± 2 Ma) and Merek (Russian Far East, 93 ± 2 Ma). Three methods of age calculations, including 208Pb/206Pb-207Pb/206Pb inverse isochron age, Tera-Wasserburg Concordia lower intercept age, and 207Pb-corrected 206Pb*/238U age were used and the comparison of the results is discussed. In all cases, the dated cassiterite from the ore deposits agreed, within error, with the established period of magmatism of the associated granitic rock.


2021 ◽  
Author(s):  
Brian Nharara ◽  
Eugenia Airiyants ◽  
Ol'ga Kiseleva ◽  
Dmitriy Belyanin ◽  
Petr Roshchektaev ◽  
...  

<p>Vladimirskoe gold-rare metal deposits are located in the Urik-Kitoiskaya gold zone, at the edges of the Neoarchean age Gargan microcontinent, in the southeastern part of the Eastern Sayan. Gold mineralization is localized in sheared, beresitised mineralized zones among granite gneiss of the Gargan Group (NARg). The width of the zones is 3-10 m and the length is up to 800 m. The material composition of the ores is sulfide-carbonate-quartz. The main ore minerals are pyrite, chalcopyrite, pyrrhotite, galena, sphalerite, as well as tellurides and sulfosalts of silver, lead, and bismuth. The main minerals at the deposit are gold, associated - silver, and bismuth, associated with sulfide mineralization. Average gold grades in ores are 7-12 g / t.</p><p>Mineralized ore zones are associated with faults, and are often localized at their intersection with dike complexes. Several fault systems are identified in the deposit. The first-order fault system is a right-lateral dip-slip with a submeridional strike. The second-order system has a northwest strike and represents zones of viscous faults, expressed by zones of cleavage, beresitisation, silicification, and sulfidization, which are associated with gold mineralization.</p><p>There are two types of dike complexes within the region. The first dike complex of the barun-holba subvolcanic complex (O-S) has basic composition. Dikes are widespread throughout the entire area and are characterized by diabase porphyrites, metabasalts, and more rarely, basaltic andesite porphyrites. The rocks have a porphyry structure with phenocrysts (1-3 cm) characterized by plagioclase, altered to form epidote and muscovite. Large porphyry segregations up to 10 cm, bearing traces of deformation processes are observed in some cases. The groundmass has a fine-grained, microlepidogranoblastic structure and is composed of a secondary epidote-chlorite-albite aggregate.</p><p>The second dike complex is less pronounced and is characterized by felsic dikes belonging to the Early Paleozoic Holba complex. It is located in the southeastern part of the region and is characterized by granite-porphyries, leucocratic pegmatoid granites, and dacites. Dikes of felsic composition have a felsic structure caused by microliths of albitised plagioclase, biotite, and secondary minerals (chlorite, epidote, amphibole, calcite).</p><p>Dikes and dike belts are the ore-controlling structures of gold mineralization. In intersecting zones of a northwestern strike, gold mineralization is concentrated near dikes and gradually fades away as we move from them. The greatest development of mineralized zones and the associated quartz-vein ore mineralization can be observed at the intersection of fault zones with dikes. In this case, ore columns with a thickness of 20-50 m formed, extending to a depth of 3 km. Vladimirskoe deposits belong to vein-dike ore-magmatic systems, their source of ore matter is of deep origin.</p><p>This work is supported by RFBR grants: No. 19-05-00764 and the Russian Ministry of Education and Science. </p><p>References:</p><p>Gordienko I.V. et al., // Geology Ore Deposits. 2016. V. 58, № 5, P. 405-429.</p><p>Seminsky Zh. V. et al. // Proceedings of the Siberian Branch of the Section of Earth Sciences of the Russian Academy of Sciences. T. 45, N. 2. 2014. P. 19-34.</p>


2019 ◽  
Vol 487 (4) ◽  
pp. 424-427
Author(s):  
L. N. Kogarko

Detailed studies have shown that changing the forms of eudialyte release (and the time of its crystallization) is a new geochemical criterion for the ore - bearing of alkaline magmas for rare metal (eudialyte ores). A new ore-bearing principle of alkaline magmas has been formulated: a prerequisite for the formation of an ore deposit is the early saturation of alkaline magmas with respect to the ore mineral. If the concentration of the ore component is significantly lower than the cotectic concentration (saturation), then the melt saturation and crystallization of the ore mineral will be carried out at the later stages of rock formation in a small volume of interstitial melt, when the phenomena of convective-gravity differentiation and segregation of mineral phases in the form of ore deposits are hampered. This leads to the dispersion of ore components in the form of xenomorphic forms of accessory minerals. Rocks of the differentiated complex (lower zone of the Lovozero deposit), and of the Khibiny massif, containing xenomorphic eudialyte, are not promising for eudialyte ores. Eudialyte deposits are associated with the upper zone of the Lovozero intrusion containing idiomorphic early eudialyte. The saturation of the initial magma in relation to eudialyte occurs after crystallization of about 80% of the intrusion. The proposed criterion is applicable to the largest alkaline massifs in the world. With the Ilimaussaksky massif (Greenland), in the rocks of which early, crystallized, idiomorphic eudialyte, there is a superlarge eudialyte ore deposit while in the Khibiny eudialyte ore is absent.


Sign in / Sign up

Export Citation Format

Share Document