scholarly journals The Kultuma Au–Cu–Fe-Skarn Deposit (Eastern Transbaikalia): Magmatism, Zircon Geochemistry, Mineralogy, Age, Formation Conditions and Isotope Geochemical Data

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 12
Author(s):  
Yury O. Redin ◽  
Anna A. Redina ◽  
Viktor P. Mokrushnikov ◽  
Alexandra V. Malyutina ◽  
Vladislav F. Dultsev
Keyword(s):  
Low Temperature ◽  
Isotope Composition ◽  
Geochemical Data ◽  
Type I ◽  
Skarn Deposit ◽  
Potassic Alteration ◽  
Magmatic Rocks ◽  
Eastern Transbaikalia ◽  
Propylitic Alteration ◽  
Host Rocks

The Kultuma deposit is among the largest and most representative Au–Cu–Fe–skarn deposits situated in Eastern Transbaikalia. However, its genetic classification is still a controversial issue. The deposit is confined to the similarly named massif of the Shakhtama complex, which is composed mainly of quartz monzodiorite-porphyry and second-phase monzodiorite-porphyry. The magmatic rocks are characterized by a low Fe2O3/FeO ratio, low magnetic susceptibility and belong to meta-aluminous, magnesian high-potassic calc-alkalic reduced granitoids of type I. The results of 40Ar-39Ar and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating showed that the formation of magmatic rocks proceeded during the Late Jurassic time: 161.5–156.8 Ma. Relatively low Ce/Ce*, Eu/Eu* and Dy/Yb ratios in the zircons indicate that the studied magmatic rocks were formed under relatively reduced conditions and initially contained a rather low amount of magmatic water. A mineralogical–geochemical investigation allowed us to outline five main stages (prograde skarn, retrograde skarn, potassic alteration, propylitic (hydrosilicate) alteration and late low-temperature alteration) of mineral formation, each of them being characterized by a definite paragenetic mineral association. The major iron, gold and copper ores were formed at the stage of retrograde skarn and potassic alteration, while the formation of polymetallic ores proceeded at the stage of propylitic alteration. The obtained timing of the formation of retrograde skarn (156.3 Ma) and magmatic rocks of the Shakhtama complex, along with the direct geological observations, suggest their spatial–temporal and genetic relationship. The data obtained on the age of magmatic rocks and ore mineralization are interpreted as indicating the formation of the Kultuma deposit that proceeded at the final stages of collision. Results of the investigation of the isotope composition of S in sulfide minerals point to their substantial enrichment with the heavy sulfur isotope (δ34S from 6.6 to 16‰). The only exclusion with anomalous low δ34S values (from 1.4 to 3.7‰) is pyrrhotite from retrograde skarns of the Ochunogda region. These differences are, first of all, due to the composition of the host rocks. Results of the studies of C and O isotope composition allow us to conclude that one of the main sources of carbon was the host rocks of the Bystrinskaya formation, while the changes in the isotope composition of oxygen are mainly connected with decarbonization processes and the interactions of magmatic fluids, host rocks and meteoric waters. The fluids that are responsible for the formation of the mineral associations of retrograde skarns and the zones of potassic alteration at the Kultuma deposit were reduced, moderately hot (~360–440 °С) and high-pressure (estimated pressure is up to 2.4 kbar). The distinguishing features of the fluids in the zones of potassic alteration at the Ochunogda region are a lower concentration and lower estimated pressure values (~1.7 kbar). The propylitic alteration took place with the participation of reduced lower-temperature (~280–320 °C) and lower-pressure (1–1.2 kbar) fluids saturated with carbon dioxide, which were later on diluted with meteoric waters to become more water-rich and low-temperature (~245–260 °C). The studies showed that the main factors that affected the distribution and specificity of mineralization are magmatic, lithological and structural–tectonic ones. Results of the studies allow us to classify the Kultuma deposit as a Au–Cu–Fe–skarn deposit related to reduced intrusion.

scholarly journals Genome-wide identification and expression pattern analysis of lipoxygenase gene family in banana

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fan Liu ◽  
Hua Li ◽  
Junwei Wu ◽  
Bin Wang ◽  
Na Tian ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Pcr Analysis ◽  
Type I ◽  
Segmental Duplications ◽  
Expression Levels ◽  
Genome Wide ◽  
Encoded Proteins ◽  
Gene Structures ◽  
Lipoxygenase Gene Family

AbstractThe LOX genes have been identified and characterized in many plant species, but studies on the banana LOX genes are very limited. In this study, we respectively identified 18 MaLOX, 11 MbLOX, and 12 MiLOX genes from the Musa acuminata, M. balbisiana and M. itinerans genome data, investigated their gene structures and characterized the physicochemical properties of their encoded proteins. Banana LOXs showed a preference for using and ending with G/C and their encoded proteins can be classified into 9-LOX, Type I 13-LOX and Type II 13-LOX subfamilies. The expansion of the MaLOXs might result from the combined actions of genome-wide, tandem, and segmental duplications. However, tandem and segmental duplications contribute to the expansion of MbLOXs. Transcriptome data based gene expression analysis showed that MaLOX1, 4, and 7 were highly expressed in fruit and their expression levels were significantly regulated by ethylene. And 11, 12 and 7 MaLOXs were found to be low temperature-, high temperature-, and Fusarium oxysporum f. sp. Cubense tropical race 4 (FocTR4)-responsive, respectively. MaLOX8, 9 and 13 are responsive to all the three stresses, MaLOX4 and MaLOX12 are high temperature- and FocTR4-responsive; MaLOX6 and MaLOX17 are significantly induced by low temperature and FocTR4; and the expression of MaLOX7 and MaLOX16 are only affected by high temperature. Quantitative real-time PCR (qRT-PCR) analysis revealed that the expression levels of several MaLOXs are regulated by MeJA and FocTR4, indicating that they can increase the resistance of banana by regulating the JA pathway. Additionally, the weighted gene co-expression network analysis (WGCNA) of MaLOXs revealed 3 models respectively for 5 (MaLOX7-11), 3 (MaLOX6, 13, and 17), and 1 (MaLOX12) MaLOX genes. Our findings can provide valuable information for the characterization, evolution, diversity and functionality of MaLOX, MbLOX and MiLOX genes and are helpful for understanding the roles of LOXs in banana growth and development and adaptations to different stresses.

Dissolution and recrystallization in modern shelf carbonates: evidence from pore water and solid phase chemistry

1993 ◽  
Vol 344 (1670) ◽  
pp. 27-36 ◽  
Keyword(s):  
Organic Matter ◽  
Pore Water ◽  
Solid Phase ◽  
Chemical Exchange ◽  
Isotope Composition ◽  
Geochemical Data ◽  
Carbonate Sediments ◽  
Pore Waters ◽  
Carbonate Minerals ◽  
Carbonate Production

We present an overview of geochemical data from pore waters and solid phases that clarify earliest diagenetic processes affecting modern, shallow marine carbonate sediments. Acids produced by organic matter decomposition react rapidly with metastable carbonate minerals in pore waters to produce extensive syndepositional dissolution and recrystallization. Stoichiometric relations among pore water solutes suggest that dissolution is related to oxidation of H 2 S which can accumulate in these low-Fe sediments. Sulphide oxidation likely occurs by enhanced diffusion of O 2 mediated by sulphide-oxidizing bacteria which colonize oxic/anoxic interfaces invaginating these intensely bioturbated sediments. Buffering of pore water stable isotopic compositions towards values of bulk sediment and rapid 45 Ca exchange rates during sediment incubations demonstrate that carbonate recrystallization is a significant process. Comparison of average biogenic carbonate production rates with estimated rates of dissolution and recrystallization suggests that over half the gross production is dissolved and/or recrystallized. Thus isotopic and elemental composition of carbonate minerals can experience significant alteration during earliest burial driven by chemical exchange among carbonate minerals and decomposing organic matter. Temporal shifts in palaeo-ocean carbon isotope composition inferred from bulk-rocks may be seriously compromised by facies-dependent differences in dissolution and recrystallization rates.

AusGeochem and Big Data Analytics in Low-Temperature Thermochronology

2021 ◽  
Author(s):  
Samuel Boone ◽  
Fabian Kohlmann ◽  
Moritz Theile ◽  
Wayne Noble ◽  
Barry Kohn ◽  
...  
Keyword(s):  
Big Data ◽  
Low Temperature ◽  
Data Analytics ◽  
Big Data Analytics ◽  
Application Programming Interface ◽  
Large Datasets ◽  
Geochemical Data ◽  
Advisory Group ◽  
New Era ◽  
Analytical Instruments

<p>The AuScope Geochemistry Network (AGN) and partners Lithodat Pty Ltd are developing AusGeochem, a novel cloud-based platform for Australian-produced geochemistry data from around the globe. The open platform will allow laboratories to upload, archive, disseminate and publish their datasets, as well as perform statistical analyses and data synthesis within the context of large volumes of publicly funded geochemical data. As part of this endeavour, representatives from four Australian low-temperature thermochronology laboratories (University of Melbourne, University of Adelaide, Curtin University and University of Queensland) are advising the AGN and Lithodat on the development of low-temperature thermochronology (LTT)-specific data models for the relational AusGeochem database and its international counterpart, LithoSurfer. These schemas will facilitate the structured archiving of a wide variety of thermochronology data, enabling geoscientists to readily perform LTT Big Data analytics and gain new insights into the thermo-tectonic evolution of Earth’s crust.</p><p>Adopting established international data reporting best practices, the LTT expert advisory group has designed database schemas for the fission track and (U-Th-Sm)/He methods, as well as for thermal history modelling results and metadata. In addition to recording the parameters required for LTT analyses, the schemas include fields for reference material results and error reporting, allowing AusGeochem users to independently perform QA/QC on data archived in the database. Development of scripts for the automated upload of data directly from analytical instruments into AusGeochem using its open-source Application Programming Interface are currently under way.</p><p>The advent of a LTT relational database heralds the beginning of a new era of Big Data analytics in the field of low-temperature thermochronology. By methodically archiving detailed LTT (meta-)data in structured schemas, intractably large datasets comprising 1000s of analyses produced by numerous laboratories can be readily interrogated in new and powerful ways. These include rapid derivation of inter-data relationships, facilitating on-the-fly age computation, statistical analysis and data visualisation. With the detailed LTT data stored in relational schemas, measurements can then be re-calculated and re-modelled using user-defined constants and kinetic algorithms. This enables analyses determined using different parameters to be equated and compared across regional- to global scales.</p><p>The development of this novel tool heralds the beginning of a new era of structured Big Data in the field of low-temperature thermochronology, improving laboratories’ ability to manage and share their data in alignment with FAIR data principles while enabling analysts to readily interrogate intractably large datasets in new and powerful ways.</p>

Sources of the magmatic rocks of the Mendeleev Rise, Arctic Ocean: Evidence from isotope-geochemical data

2015 ◽  
Vol 53 (6) ◽  
pp. 487-500 ◽  
Author(s):  
A. A. Kremenetskii ◽  
Yu. A. Kostitsyn ◽  
A. F. Morozov ◽  
P. V. Rekant
Keyword(s):  
Arctic Ocean ◽  
Geochemical Data ◽  
Magmatic Rocks

scholarly journals Petrogeochemical and isotopic characteristics, connection with magmatism of tungsten deposits of Aginskaya and Argunskaya structural-formation zones of the Eastern Transbaikalia

LITOSFERA ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 262-272
Author(s):  
B. N. Abramov ◽  
V. F. Posokhov
Keyword(s):  
Oxygen Isotope ◽  
Inductively Coupled Plasma ◽  
Isotope Composition ◽  
Close Correlation ◽  
Infrared Region ◽  
Emission Analysis ◽  
Structural Formation ◽  
Geological Institute ◽  
Eastern Transbaikalia ◽  
Tungsten Deposits

Research subject. Tungsten deposits of the Aginsky and Argunsky structural-formation zones in the Eastern Transbaikalia. The aim was to clarify the sources and conditions for the formation of tungsten mineralisation, as well as to clarify a relationship between magmatism and tungsten mineralisation. The conditions of deposit formation were studied using data on the chemical composition of rocks and ores and the oxygen isotopic composition of the ore veins of tungsten deposits.Methods. The elemental composition of rocks was determined by the methods of X-ray fluorescence and standard chemical analysis; the concentration of rare-earth elements was determined by sorption-atomic emission analysis with inductively coupled plasma (Geological Institute SB RAS, Ulan-Ude). The examination of oxygen isotope composition was carried out at the Geological Institute of SB RAS (Ulan-Ude) using a MIR 10-30 system of laser heating with a 100W CO2 laser and 10.6 microns wavelength in the infrared region in the presence of a BrF5 reagent (analyst V.F. Posokhov).Results and conclusions. It was established that granites in the Kukulbey complex of the Antonovogorsky and Bukukinsky tungsten deposits correspond to granites of an ilmenite series, while the ores in the Spokoininsky deposit are associated with the granites of a magnetite series. A close correlation was established between W with Ta, Nb, Hf and As, indicating similar compositions of ore-bearing sources of the tungsten deposits. For Barun-Shiveinsky, Antonovogorsky and Bukukinsky deposits, the oxygen isotope compositions in the fluid in equilibrium with quartz of the productive stage was calculated, indicating the magmatic sources of mineralisation.

scholarly journals An Overview of the Tectonic Evolution of the Indochina block and Granitoid Emplacement, particularly in the central and south Vietnam

2020 ◽  
Vol 23 (3) ◽  
pp. First
Author(s):  
Tuan Anh Nguyen ◽  
Ngo Tran Thien Quy ◽  
Vu Thi Hao ◽  
Pham Minh
Keyword(s):  
Geochemical Data ◽  
Language Program ◽  
R Language ◽  
Magmatic Rocks ◽  
South Vietnam ◽  
Granitic Magmatism ◽  
Granitoid Emplacement ◽  
Rock Analysis ◽  
Geochemical Data Analysis ◽  
Southwest Part

Introduction: Vietnam is mainly located within the Indochina block in Southeast Asia. Asmall northern part of Vietnam belongs to the South China block, the southwest part liesadjacent to the Sibumasu block and opens to the East Sea on the east side. Tectonicactivities in Vietnam were very complicated they relate to intense interactions betweenmany geological blocks at different times. Magmatic emplacement is the final and instantproduct of tectonic activities. Methods: Geochemical data analysis from rock samples withinVietnam collected by other researchers has been reused in the scope of this study to verifythe relation between tectonic evolutions and their granitic magmatism. GCD (GeochemicalData Toolkit), an R language program for handling and recalculation of geochemical data. Results: Geochronology and geotectonic model derived from rock analysis have beenascertained main tectonic evolutions of the Indochina. The current granitoidclassification in Vietnam mostly based on petrographical studies. The Nui Cam granitoid isbeing classified as Deo Ca, Dinh Quan granitoid. However, based on trace elements, they aredifferent. They may belong to different granitoid system. Conclusion: Major tectonic eventswithin the Indochina block are well supported by the nature of granitoid emplacements. Petrological studies of these magmatic rocks would bring out valuable information toconfirm and clearly understand the tectonic evolutions of the region. Igneous rocksclassification must based on tectonic fundamental instead of petrographical studies.

Exemples de mélange de magmas en contexte plutonique: les enclaves des tonalites–granodiorites du massif de Bono (Sardaigne septentrionale)

1989 ◽  
Vol 26 (6) ◽  
pp. 1264-1281 ◽  
Author(s):  
C. Cocirta ◽  
J. B. Orsini ◽  
C. Coulon
Keyword(s):  
Geochemical Data ◽  
Mixing Process ◽  
Calc Alkaline ◽  
Specific Group ◽  
Mineralogical Analysis ◽  
Magmatic Origin ◽  
Interaction Mechanisms ◽  
Compositional Variations ◽  
End Members ◽  
Host Rocks

In calc-alkaline orogenic plutons, the dark xenoliths and their host rocks must be considered the expression of partial mixing of magma.Three associations of this type have been investigated and are illustrated by the Bono pluton (northern Sardinia)— a composite pluton including three intrusives of different nature (tonalitic to granodioritic) and containing a very large number of basaltic xenoliths of magmatic origin. Detailed mineralogical analysis of the two end members in each association, coupled with geochemical data, has determined the major petrogenetic mechanisms intervening in the mixing process in a plutonic setting: temperature equilibration, mechanical exchanges of crystals, chemical exchanges, etc. The most important result of this article, however, is to show that each intrusion is related to a specific group of xenoliths that is characterized by constant FeOt/MgO. The latter reflects the different composition of basaltic components, and it is concluded that each intrusive event is associated with a unique mixing episode. As in volcanic settings, the mixing process may have initiated the intrusion.The extreme compositional variations in the magmatic xenoliths, recognized in several series of orogenic plutons, is explained here by different initial basaltic end members and by variation in the intensity of the interaction mechanisms. [Journal Translation]

MAPPING THE MINERAL ZONATION AT THE ERNEST HENRY IRON OXIDE COPPER-GOLD DEPOSIT: VECTORING TO Cu-Au MINERALIZATION USING MODAL MINERALOGY

2022 ◽  
Vol 117 (2) ◽  
pp. 485-494
Author(s):  
Tobias U. Schlegel ◽  
Renee Birchall ◽  
Tina D. Shelton ◽  
James R. Austin
Keyword(s):  
Iron Oxide ◽  
Gamma Ray ◽  
Geochemical Data ◽  
Iocg Deposits ◽  
Mineral Mapping ◽  
Gamma Ray Spectrometer ◽  
Mineral Assemblages ◽  
Copper Gold ◽  
Host Rocks ◽  
Acid Alteration

Abstract Iron oxide copper-gold (IOCG) deposits form in spatial and genetic relation to hydrothermal iron oxide-alkali-calcic-hydrolytic alteration and thus show a mappable zonation of mineral assemblages toward the orebody. The mineral zonation of a breccia matrix-hosted orebody is efficiently mapped by regularly spaced samples analyzed by the scanning electron microscopy-integrated mineral analyzer technique. The method results in quantitative estimates of the mineralogy and allows the reliable recognition of characteristic alteration as well as mineralization-related mineral assemblages from detailed mineral maps. The Ernest Henry deposit is located in the Cloncurry district of Queensland and is one of Australia’s significant IOCG deposits. It is known for its association of K-feldspar altered clasts with iron oxides and chalcopyrite in the breccia matrix. Our mineral mapping approach shows that the hydrothermal alteration resulted in a characteristic zonation of minerals radiating outward from the pipe-shaped orebody. The mineral zonation is the result of a sequence of sodic alteration followed by potassic alteration, brecciation, and, finally, by hydrolytic (acid) alteration. The hydrolytic alteration primarily affected the breccia matrix and was related to economic mineralization. Alteration halos of individual minerals such as pyrite and apatite extend dozens to hundreds of meters beyond the limits of the orebody into the host rocks. Likewise, the Fe-Mg ratio in hydrothermal chlorites changes systematically with respect to their distance from the orebody. Geochemical data obtained from portable X-ray fluorescence (p-XRF) and petrophysical data acquired from a magnetic susceptibility meter and a gamma-ray spectrometer support the mineralogical data and help to accurately identify mineral halos in rocks surrounding the ore zone. Specifically, the combination of mineralogical data with multielement data such as P, Mn, As, P, and U obtained from p-XRF and positive U anomalies from radiometric measurements has potential to direct an exploration program toward higher Cu-Au grades.

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