Geologic Structure, Mineralogy, and Geochemistry of the Nerunda Gold Ore Field (Northern Transbaikalia)

2021 ◽  
Vol 62 (10) ◽  
pp. 1139-1156
Author(s):  
I.V. Chetvertakov ◽  
V.A. Vanin ◽  
I.A. Demin
Keyword(s):  
Early Stage ◽  
Gold Deposits ◽  
Geologic Structure ◽  
Gold Ore ◽  
Northern Transbaikalia ◽  
Ore Mineralization ◽  
Two Stages ◽  
Geochemical Studies ◽  
Ore District ◽  
Erosion Zone

Abstract —We consider the geologic structure of the Nerunda gold ore field located in the Nerunda–Mama ore district in northern Transbaikalia. Gold–quartz low-sulfide formation and ore-bearing carbonate-terrigenous strata and intrusive complexes are briefly described. An ore complex of beresite–listvenite metasomatites hosting carbonate–quartz veins and vein–veinlet zones is characterized. Two stages of ore formation have been recognized. Anomalous geochemical associations and the composition of ore mineralization typical of these stages have been established. Mineralogical and geochemical studies of gold-bearing metasomatites of the Nerunda ore field were carried out. The known geochemical and mineralogical search criteria used for the assessment of the erosion zone level of gold deposits were applied to the geologic conditions of the Nerunda ore field and the Nerunda–Mama gold ore district as a whole. The emphasis was made on the express assessment of the erosion zone level at the early stage of prospecting. We draw a conclusion about the gold potential of the poorly studied ore objects at depth and give guidelines for the following geological prospecting.

scholarly journals GEOLOGY AND ORE MINERALISATION OF NEOGENE SEDIMENTARY ROCK HOSTED LS EPITHERMAL GOLD DEPOSIT AT PANINGKABAN, BANYUMAS REGENCY, CENTRAL JAVA, INDONESIA

2015 ◽  
Vol 7 (2) ◽  
pp. 75
Author(s):  
Arifudin Idrus ◽  
Fahmi Hakim ◽  
I Wayan Warmada ◽  
Mochammad Aziz ◽  
Jochen Kolb ◽  
...  
Keyword(s):  
Base Metal ◽  
Gold Mineralization ◽  
Early Stage ◽  
Gold Deposits ◽  
Epithermal Gold ◽  
Central Java ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Miners

Low suphidation (LS) epithermal gold deposits were recently found in the Paningkaban area, Central Java province, Indonesia, with more than five hundred artisanal gold miners currently operating in the area. This study is aimed to understand the geological factors controlling the gold mineralization and to characterize the alteration and ore mineralogy of the deposit. Several epithermal veins/veinlets trending N–S, NW–SE, and NE–SW are hosted by Tertiary turbiditic volcanoclastic sedimentary rocks of the Halang formation. This formation is composed of looping gradation of sandstone and siltstone units. Pre- and syn-mineralization structures such as extension joints, normal sinitral fault and sinitral fault control the gold mineralization. Fault movements formed dilational jogs manifested by NW-SE-trending en-echelon tension gash veins. Four main alteration zones are identified: (a) phyllic, (b) argillic, (c) sub propylitic and (d) weak subpropylitic. Ore minerals consist of native gold, electrum, native silver, pyrite, chalcopyrite, sphalerite, galena, arsenopyrite, cubanite, marcasite, covellite and tennantite, which are commonly associated withargillic alteration. Vein structures such as massive, swarm and low angle veins, stockwork and veins dispersed in diatreme breccia are present. Normal banded, cockade, crustiform, bladed carbonates as well as, comb and saccharoidal features are the typical vein textures. It is noteworthy that the veins are basically composed of carbonate with minor quartz at gold grades of up to 83 g/t Au. Based on the vein structures and textures, four stages of ore mineralization were developed consisting of (a) early stage (fluidized breccia and quartz vein), (b) middle stage (carbonate base metal), (c) late stage (late carbonate), and supergene stage. Gold mineralization originated mainly during middle and late stages, particularly in association with cockade, crustiform, bladed carbonate base metal veins. Based on those various features, the LS epithermal deposit in the study area is categorized as carbonate-base metalgold mineralization type.

Ore Mineralization in Adular-Fluorite Metasomatites: Evidence of the Podgolechnoe Alkalic-Type Epithermal Gold Deposit (Central Aldan Ore District, Russia)

2017 ◽  
Vol 743 ◽  
pp. 417-421 ◽  
Author(s):  
Vasilii Ivanovich Leontev ◽  
Yackov Yur’evich Bushuev
Keyword(s):  
Ore Deposits ◽  
Epithermal Gold ◽  
Gold Ore ◽  
Ore Bodies ◽  
Epithermal Gold Deposit ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Ore Deposit ◽  
Host Rocks ◽  
Ore District

The Podgolechnoe deposit, which belongs to the alkalic-type (A-type) epithermal gold-ore deposits, lies in the Central Aldan ore district (Russia). Gold-ore mineralization is associated with a volcano-plutonic complex made of rocks of the monzonite-syenite formation (J3–K1). The ore bodies are localized in the crushing zones developed after crystalline schists, gneisses, and granites of the crystalline basement complexes (Ar–Pr). Metasomatic alterations in host rocks have potassic specialization. Vein ore minerals are adular, fluorite, roscoelite, sericite, and carbonate. Ore minerals are pyrite, galena, sphalerite, cinnabar, brannerite, monazite, bismuth telluride, stutzite, hessite, petzite, montbraite, and native gold. The deposit has been explored as a gold-ore deposit, however, due to complex composition of ores there is a need to reveal the possibilities of the integrated development of this deposit. This could provide for a reserve increment and an increase in the gross recoverable value of ores due to the extraction of associated components.

scholarly journals NEW DATA ON GEOLOGY AND GOLDENCE OF THE PROSPECTIVE AREAS «TAEZHKA» AND «UTRENNAYA» IN THE DAMBUKINSKY ORE DISTRICT (UPPER AMUR PRIAMURYE)

2020 ◽  
pp. 72-80
Author(s):  
ANTON VLADIMIROVICH MELNIKOV ◽  
◽  
PAVEL IVANOVICH ROMANOV ◽  
TATIANA VLADISLAVOVNA ROMANOVA ◽  
◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Structure Formation ◽  
Deep Structure ◽  
Gold Deposits ◽  
Structural Position ◽  
Gold Ore ◽  
Ore Minerals ◽  
Real Composition ◽  
Ore District ◽  
Gold Bearing

Information is given on the gold bearing of the ore-prospective areas «Tayezhka» and «Utrenniya» of the Dambukinsky Оre District of the Upper Priamurye/ Taking into account new data on geology, geochemistry, real composition of ores, description and comparative analysis of gold-ore manifestations are given. The prerequisites for the formation and criteria for the forecast and search of industrial gold deposits in this area of Upper Priamurya are described: geotectonic and structural position, deep structure, formation features, hydrothermal changes of rocks, mineral and geochemical associations, tipomorphism of gold and ore minerals, etc.

Ore Mineralization of the Epithermal Samolazovskoe Gold-Ore Deposit, Aldan Shield (Russia)

2018 ◽  
Vol 769 ◽  
pp. 213-219 ◽  
Author(s):  
Vasilii Ivanovich Leontev ◽  
Konstantin Chernigovtsev
Keyword(s):  
Aldan Shield ◽  
Crystalline Basement ◽  
Linear Type ◽  
Ore Deposit ◽  
Gold Ore ◽  
Ore Minerals ◽  
Ore Mineralization ◽  
Gold Ore Deposit ◽  
Full Volume ◽  
Ore District

The Samolazovskoe gold-ore deposit is located in the Central Aldan ore district (Russia) within the Yukhta multiphase volcano-plutonic massif, consisted of rocks of the monzonite-syenite formation (J3–K1). Four hydrothermal-metasomatic mineral parageneses are distinguished in the deposit: skarn, developed at the contact of syenites and rocks of the carbonate cover (V–Є); gumbeite, superimposed on the rocks of the intrusive massif; feldspatholite, developed in granite gneisses of the crystalline basement (PR) at their contact with the intrusive massif; ore-bearing fluorite–roscoelite–carbonate–quartz, superimposed on all above-mentioned types of mineralization. The main types of mineralization in the Samolazovskoe deposit are the following: (1) vein-disseminated linear type (now recovered in full volume); (2) vein-disseminated stockwork type; and (3) breccia-like type. Vein-filling minerals of the ores are quartz, fluorite, roscoelite, and carbonate. The main ore minerals are pyrite and marcasite; the secondary ones are bournonite, fahlore, sphalerite, galena, and chalcopyrite. Coloradoite and calaverite are less common; native gold occurs very rarely. Pyrite and marcasite are characterized by the following impurities (wt%): Sb (0.64–1.90), As (0.94–5.25), Te (1.02–3.82), and V ( 0.21–0.31).

scholarly journals AGE CONSTRAINTS AND METALLOGENIC PREDICTION OF GOLD DEPOSITS IN THE AKZHAL-BOKO-ASHALIN ORE ZONE (ALTAI ACCRETION-COLLISION SYSTEM)

2021 ◽  
Vol 12 (2) ◽  
pp. 392-408
Author(s):  
Yu. A. Kalinin ◽  
K. R. Kovalev ◽  
A. N. Serdyukov ◽  
A. S. Gladkov ◽  
V. P. Sukhorukov ◽  
...  
Keyword(s):  
Gold Mineralization ◽  
Gold Deposits ◽  
Igneous Rocks ◽  
Isotope Geochronology ◽  
Ore Formation ◽  
Gold Ore ◽  
Ore Mineralization ◽  
East Kazakhstan ◽  
Age Constraints ◽  
Gold Bearing

We present new age constraints for igneous rocks and ore-metasomatic formations of the gold deposits in the Akzhal-Boko-Ashalin ore zone. In terms of their ore formation, these deposits correspond mainly to the orogenic type, which generally reflects specific metallogeny of the West Kalba gold-bearing belt in East Kazakhstan. Gold-quartz veins and mineralized zones of the gold-sulphide formation are confined to fractures feathering regional NW-striking and sublatitudinal faults. Their common features include the following: gold-bearing veinlet-disseminated pyrite-arsenopyrite ores that are localized in carbonaceous-sandy-schist and turbidite strata of different ages; structural-tectonic control of mineralization, numerous dikes of medium-basic compositions in ore-control zones; and the presence of post-orogenic heterochronous granite-granodiorite rocks, although their relation to gold-ore mineralization is not obvious. Igneous rocks of the study area have similar ages in a narrow range from 309.1±4.1 to 298.7±3.2 Ma, which is generally consistent with the previously determined age of granitoid massifs of gold-ore fields in East Kazakhstan. A younger age (292.9±1.3 to 296.7±1.6 Ma) is estimated for felsic rocks of the dyke complex. For the ore mineralization, the 40Ar/39Ar dating of sericite from near-ore metasomatites yields two age intervals, 300.4±3.4 Ma and 279.8±4.3 Ma. A gap between of the ages of the ore mineralization and the igneous rocks is almost 20 Ma, which may indicate that the processes of ore formation in the ore field continued in an impulse-like pattern for at least 20 Ma. Nevertheless, this confirms a relationship between the hydrothermal activity in the study area and the formation and evolution of silicic igneous rocks of the given age interval, which belong to the Kunush complex, according to previous studies. This interpretation is supported by reconstructed tectonic paleostress fields, showing that directions of the main normal stress axes changed during the ore mineralization stage, which is why the ore bodies significantly differ in their orientations. The above-mentioned data are the first age constraints for the study area. Additional age determinations are needed to further improve understanding of the chronology of ore-forming processes. Actually, all the features characterizing the gold mineralization of the Akzhal, Ashalin and Dauba ore fields, including the data on lithology, stratigraphy, structural tectonics, magmatism, isotope geochronology, mineralogy and geochemistry, can be used as criteria when searching for similar ore fields in East Kazakhstan.

scholarly journals High Fat Diet Induces Adhesion of Platelets to Endothelium in Two Models of Dyslipidemia

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Jaime Gonzalez ◽  
Wendy Donoso ◽  
Natalia Díaz ◽  
María Eliana Albornoz ◽  
Ricardo Huilcaman ◽  
...  
Keyword(s):  
High Fat Diet ◽  
Early Stage ◽  
Endothelial Activation ◽  
Mice Model ◽  
High Fat ◽  
Early Stages ◽  
Endothelial Surface ◽  
Two Stages ◽  
Adhesion Of Platelets

Cardiovascular diseases (CVD) represent about 30% of all global deaths. It is currently accepted that, in the atherogenic process, platelets play an important role, contributing to endothelial activation and modulation of the inflammatory phenomenon, promoting the beginning and formation of lesions and their subsequent thrombotic complications. The objective of the present work was to study using immunohistochemistry, the presence of platelets, monocytes/macrophages, and cell adhesion molecules (CD61, CD163, and CD54), in two stages of the atheromatous process. CF-1 mice fed a fat diet were used to obtain early stages of atheromatous process, denominated early stage of atherosclerosis, and ApoE−/−mice fed a fat diet were used to observe advanced stages of atherosclerosis. The CF-1 mice model presented immunostaining on endothelial surface for all three markers studied; the advanced atherosclerosis model in ApoE−/−mice also presented granular immunostaining on lesion thickness, for the same markers. These results suggest that platelets participate in atheromatous process from early stages to advance d stages. High fat diet induces adhesion of platelets to endothelial cellsin vivo. These findings support studying the participation of platelets in the formation of atheromatous plate.

scholarly journals Observations on the Nutrition of Maggots of Australian Blow-Flies

1933 ◽  
Vol 10 (3) ◽  
pp. 237-246
Author(s):  
M. J. MACKERRAS ◽  
M. R. FRENEY
Keyword(s):  
Early Stage ◽  
Wool Fibre ◽  
Initial Growth ◽  
Full Development ◽  
Adequate Food ◽  
Acid Reaction ◽  
Keratin Hydrolysis ◽  
The Moment ◽  
The Masses ◽  
Two Stages

1. Larvae of L. cuprina and Ch. rufifacies are capable of liquefying and digesting protein media without the intervention of bacteria. Both species and L. sericata secrete tryptic and peptic enzymes and at least L. cuprina does so from the moment of hatching. Tryptase is more abundant than peptase. Predatory activity, though a normal habit of Ch. rufifacies, is not necessary for any of these species and did not occur in the masses of Lucilia larvae used for extraction of the enzymes, although they were kept for periods up to 24 hours without food. 2. Partial development of larvae occurred in sheep dung, faeces-stained wool and in the products of keratin hydrolysis. Complete development took place in wool containing a "gummy crust" of dried exudate and in some samples of faeces-stained wool. Some of the samples of faeces-stained wool and those containing a "crust" have been demonstrated serologically by Dr I. M. Mackerras to have an increased content of soluble sheep protein as compared with normal wool. A marked increase of soluble protein has been demonstrated in struck wool both chemically and serologically. 3. Moisture, warmth, shelter and aeration are essential physical conditions for larval development. In addition, an alkaline reaction is relatively favourable and an acid reaction relatively unfavourable. 4. There are normally two stages in the development of a primary strike, the first stage being from hatching up to the time the larvae attack the skin, the outer layer or epidermis of which is approximately 36µ thick (Whitnall, 1931). During this stage they must feed, if at all, on materials already present. The second stage is from the commencement of an actual skin lesion up to full development of the maggots. During this stage there is a more or less copious serous exudation, which has been shown to be an adequate food for the full development of the maggots. Faeces-staining, presence of exudate due to a prior lesion, and products of wool hydrolysis have been shown to be adequate to carry the larvae through the first stage. Wool hydrolysis on the living sheep is probably not an important factor, judging by an examination of wool samples, but we have isolated organisms which, when growing on a nutrient medium, are capable of disintegrating wool fibre. 5. The rôle of bacterial activity in strike is complex and appears to be substantially as follows: (a) to produce substances which attract the flies and stimulate them to oviposit; (b) to provide food for the initial growth of the maggots, either by rendering assimilable the inert proteins, or by causing a skin reaction with a serous exudation. 6. The immediate work for the future is a more exact determination of: (a) the nature of the food of the larvae in the early stage of growth on the living sheep; (b) the factors which influence its production; and (c) the mechanism by which the larvae invade the skin.

scholarly journals A NEW GOLD ORE REGION IN TANZANIA

2018 ◽  
pp. 55-59
Author(s):  
V. Mykhailov ◽  
А. Tots
Keyword(s):  
Gold Deposit ◽  
Shear Zone ◽  
Gold Mineralization ◽  
Lake Victoria ◽  
Gold Deposits ◽  
Mobile Belt ◽  
Gold Content ◽  
Gold Ore ◽  
Metallogenic Zone ◽  
The Republic

Tanzania is one of the leading gold mining countries in the world and the discovery of new gold resources on its territory is an actual task. Known gold deposits are concentrated mainly in the northwest of the country, in the metallogenic zone of Lake Victoria, where they are associated with the Archean greenstone belts, and to a lesser extent – in the southwest, in the ore regions of Lupa and Mpanda, confined to the Ubendian Paleoproterozoic mobile belt. With regard to the eastern regions of Tanzania, where the Proterozoic structures of the Uzagaran mobile belt are developed, until recently in this region any significant manifestations of gold mineralization were not known. As a result of our research in the northern part of the Morogoro province of the Republic of Tanzania, a new previously unknown gold deposit Mananila was discovered. It is represented by a large volume, up to 400–450 m long, up to 60–80 m thick, mineralized shear zone over intensely leached and schistosed migmatites, gneisses, amphibolites, penetrated by echelon systems of quartz veins and veinlet, steeply dipping bodies of quartz breccia up to 1.0–1.5 m thick. Gold contents range from 0.61 to 8.11 g/t, the average zone content is 2.5–3.0 g/t. Parallel to the main zone, similar structures are developed on the site, although they are of lower thickness. The forecast resources of the deposit are estimated at 20 tons of gold. 2.8 km to the east from the Mananila field, the recently discovered Mazizi gold deposit is located, and a number of small occurrences of gold are also known in the region. All these objects are located within a large shear zone of the northeastern strike, up to 4–5 km width, over 20 km in length. This serves as the basis for the identification of a new gold ore region in the northern part of the Morogoro province of the United Republic of Tanzania, within the Proterozoic mobile belt of Usagaran, the possible gold content of which has never been previously discussed in geological literature.

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