scholarly journals Multivariate Statistical Evaluation of Geochemical Data from Quartz Vein-Associated Gold Mineralisation at the Badukrom Prospect within the Tarkwaian Base

2021 ◽  
Vol 21 (1) ◽  
pp. 22-30
Author(s):  
K. P. Osei ◽  
M. Affam ◽  
C. Kusi-Manu ◽  
D. T. Kwapong
Keyword(s):  
Statistical Evaluation ◽  
Rank Correlation ◽  
Geological Mapping ◽  
Geochemical Data ◽  
Good Prospect ◽  
Multivariate Statistical ◽  
Quartz Veins ◽  
Icp Ms ◽  
Multiple Structures ◽  
Airborne Electromagnetic

The Kawere conglomerate at the base of the Tarkwaian Group in the Iduapriem Mine appears to show good prospect for hydrothermal gold mineralisation evidenced by major structures mapped from magnetic and Airborne Electromagnetic (AEM) geophysical data. Detailed geological mapping and sampling at Badukrom target which lies within the Kawere rocks confirm the presence of multiple structures as well as quartz veins indicative of potential hydrothermal gold mineralisation. Follow up soil sampling conducted within the area revealed a strong anomalous trend from the southern portion. Two diamond drilled (DD) holes pushed to delineate the extent of the anomalous zones returned narrow veins of significant gold intersections. Twenty-five (25) samples of the Badukrom hydrothermal Au mineralisation intersects were sent for analysis to ascertain the optimum pathfinder element suite for the hydrothermal targets within the Iduapriem concession. A total of fifty-nine elements were analysed via ICP-MS and ICP-OES. Multivariate statistical evaluation was carried out on the results to understand the geochemical associations of Au and the other elements to aid future exploration programmes planned for the hydrothermal targets. Multivariate analysis of the geochemical data using Pearson product-moment of correlation suggests a stronger positive correlation of gold with Iron, Antimony, Sulphur, Chromium, Vanadium respectively. However, the Spearman Rank correlation data indicates that, the optimum pathfinder elements for hydrothermal Au are: As, Sb and Te.   Keywords: Tarkwaian Base, Statistical Evaluation, Hydrothermal Mineralisation, Geochemical Data

scholarly journals Comparison of Magma Oxygen Fugacity and Zircon Hf Isotopes between Xianglushan Tungsten-Bearing Granite and Late Yanshanian Granites in Jiangxi Province, South China

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 106
Author(s):  
Xing-Yuan Li ◽  
Jing-Ru Zhang ◽  
Chun-Kit Lai
Keyword(s):  
Oxygen Fugacity ◽  
South China ◽  
Granitic Magma ◽  
Geochemical Data ◽  
Jiangxi Province ◽  
Magmatic Zircon ◽  
Late Mesozoic ◽  
Icp Ms ◽  
T Values ◽  
Southern Jiangxi Province

Jiangxi Province (South China) is one of the world’s top tungsten (W) mineral provinces. In this paper, we present a new LA-ICP-MS zircon U-Pb age and Hf isotope data on the W ore-related Xianglushan granite in northern Jiangxi Province. The magmatic zircon grains (with high Th/U values) yielded an early Cretaceous weighted mean U-Pb age of 125 ± 1 Ma (MSWD = 2.5, 2σ). Zircon εHf(t) values of the Xianglushan granite are higher (−6.9 to −4.1, avg. −5.4 ± 0.7) than those of the W ore-related Xihuanshan granite in southern Jiangxi Province (−14.9 to −11.2, avg. −12.5 ± 0.9), implying different sources between the W ore-forming magmas in the northern and southern Jiangxi Province. Compiling published zircon geochemical data, the oxygen fugacity (fO2) of the late Yanshanian granitic magmas in Jiangxi Province (the Xianglushan, Ehu, Dahutang, and Xihuashan plutons) were calculated by different interpolation methods. As opposed to the W ore-barren Ehu granitic magma, the low fO2 of the Xianglushan granitic magma may have caused W enrichment and mineralization, whilst high fO2 may have led to the coexistence of Cu and W mineralization in the Dahutang pluton. Additionally, our study suggests that the absence of late Mesozoic Cu-Mo mineralization in the Zhejiang, Jiangxi, and Anhui Provinces (Zhe-Gan-Wan region) was probably related to low fO2 magmatism in the Cretaceous.

Khipu Transcription Typologies: A Corpus-Based Study of theTextos Andinos

Ethnohistory ◽  
2021 ◽  
Vol 68 (2) ◽  
pp. 311-341
Author(s):  
Manuel Medrano
Keyword(s):  
Statistical Analysis ◽  
Sixteenth Century ◽  
Multivariate Statistical Analysis ◽  
Statistical Evaluation ◽  
Multivariate Statistical ◽  
Historical Interpretation ◽  
Spanish Conquest ◽  
Textual Interpretation ◽  
Early Colonial ◽  
And Diffusion

AbstractDespite ongoing efforts to compile both Andean khipus and their written colonial references, initiatives in this domain have emphasized the benefits of aggregation vis-à-vis preservation and diffusion, largely forgoing opportunities to analyze khipu data in aggregate. This article introduces multivariate statistical analysis to colonial khipu texts, enlisting the aid of a heretofore little-studied source: the Textos Andinos, a compilation of sixteenth-century Spanish transcriptions of Indigenous khipu “readings.” The largest syntactically annotated corpus of khipu transcriptions to date is compiled. Textual interpretation informs an exegetical typology of “paper khipus”—a division of the texts into distinguishable categories. The initial typology is expanded using the outcome of its statistical evaluation. Pre- versus postconquest content and the incorporation of currency emerge as the primary distinguishing attributes of khipu transcriptions. The expanded typology in turn enables the assessment of previous hypotheses in the study of paper khipus, responding to criticisms of their generalizability; suggestions of a diminishment in khipu complexity following the Spanish conquest are revisited and corroborated to this effect. A corpus-based study of khipu transcriptions offers a promising inroad to negotiating the highly mediated conditions of their original creation while expanding the study of khipus in the early colonial Andes. The aggregative methodology is proposed to ethnohistorians as an additional strategy for complementing and enriching historical interpretation.

scholarly journals Elemental analysis of coffee: a comparison of ICP-MS and AAS methods 

2014 ◽  
Vol 32 (No. 4) ◽  
pp. 354-359 ◽  
Author(s):  
M. Jarošová ◽  
D. Milde ◽  
M. Kuba
Keyword(s):  
Inductively Coupled Plasma ◽  
Microwave Digestion ◽  
Absorption Spectrometry ◽  
Mineral Nutrients ◽  
Multivariate Statistical Methods ◽  
Multivariate Statistical ◽  
Inductively Coupled ◽  
Icp Ms ◽  
Plasma Mass Spectrometry ◽  
Microwave Digestion System

We determined the mineral nutrients and toxic elements (Ca, Cu, Fe, Mg, Zn, Cd, Cr, Mn, Ni, and Pb) in five types of coffee by atomic absorption spectrometry and inductively coupled plasma mass spectrometry. The decomposition of the samples took place in a microwave digestion system with HNO<sub>3</sub> and H<sub>2</sub>O<sub>2</sub> reagents. Partial validation of the method was performed by using the certified reference material (NCS ZC 73014). Univariate and multivariate statistical methods were used to compare both the coffee samples and the techniques used. No significant differences were found between two used methods. Significant differences occurred between the coffee samples but only the application of multivariate statistics helps to distinguish among samples from different locations.

scholarly journals Widespread Permian granite magmatism in Lower Austroalpine units: significance for Permian rifting in the Eastern Alps

2020 ◽  
Vol 113 (1) ◽  
Author(s):  
Sihua Yuan ◽  
Franz Neubauer ◽  
Yongjiang Liu ◽  
Johann Genser ◽  
Boran Liu ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Eastern Alps ◽  
Geochemical Data ◽  
Calc Alkaline ◽  
Three Samples ◽  
High K ◽  
Icp Ms ◽  
Granite Magmatism ◽  
Austroalpine Unit ◽  
Granite Suite

Abstract The Grobgneis complex, located in the eastern Austroalpine unit of the Eastern Alps, exposes large volumes of pre-Alpine porphyric metagranites, sometimes associated with small gabbroic bodies. To better understand tectonic setting of the metagranites, we carried out detailed geochronological and geochemical investigations on the major part of the porphyric metagranites. LA–ICP–MS zircon U–Pb dating of three metagranites sampled from the Grobgneis complex provides the first reliable evidence for large volumes of Permian plutonism within the pre-Alpine basement of the Lower Austroalpine units. Concordant zircons from three samples yield ages at 272.2 ± 1.2 Ma, 268.6 ± 2.3 Ma and 267.6 ± 2.9 Ma interpreted to date the emplacement of the granite suite. In combination with published ages for other Permian Alpine magmatic bodies, the new U–Pb ages provide evidence of a temporally restricted period of plutonism (“Grobgneis”) in the Raabalpen basement Complex during the Middle Permian. Comparing the investigated basement with that of the West Carpathian basement, we argue that widespread Permian granite magmatism occurred in the Lower Austroalpine units. They belong to the high-K calc-alkaline to shoshonitic S-type series on the base of geochemical data. Zircon Hf isotopic compositions of the Grobgneis metagranites show εHf(t) values of − 4.37 to − 0.6, with TDM2 model ages of 1.31–1.55 Ga, indicating that their protoliths were derived by the recycling of older continental crust. We suggest that the Permian granitic and gabbroic rocks are considered as rifted-related rocks in the Lower Austroalpine units and are contemporaneous with cover sediments.

How to disclose local equilibrium in subducted metapelites from the Cima Lunga Unit (Central Alps)

2020 ◽  
Author(s):  
Francesca Piccoli ◽  
Pierre Lanari ◽  
Jörg Hermann ◽  
Thomas Pettke
Keyword(s):  
High Pressure ◽  
Early Stage ◽  
Local Equilibrium ◽  
White Mica ◽  
Geochemical Data ◽  
Ultramafic Rocks ◽  
Central Alps ◽  
Large White ◽  
Icp Ms ◽  
Polyphase Inclusions

&lt;p&gt;Subducted metapelites are more prone to re-equilibrate during exhumation than mafic or ultramafic rocks to the point that recognizing high-pressure (HP) relicts is often very challenging. Geologic evidence from the Cima Lunga Unit (Central Alps) show this apparent discrepancy between high to ultra-high pressure metamorphism (28 kbar and 780 &amp;#176;C) recorded in mafic/ultramafic lenses, and Barrovian metamorphism (&lt;10 kbar, 650&amp;#176;C) in the adjacent metapelitic rocks. We collected a white mica &amp;#8211; garnet &amp;#8211; biotite &amp;#8211; plagioclase &amp;#8211; kyanite (+ quartz, + zircon, + rutile) bearing metapelite adjacent to the garnet metaperidotite lens that displays an apparently well equilibrated Barrovian mineral assemblage (garnet + plagioclase + biotite), with no macroscopic or microtextural indication of a HP and/or HT metamorphic event (e.g. omphacite crystals; migmatitic texture; polyphase inclusions). Nevertheless, microstructures like atoll-like garnet or large white mica flakes surrounded by biotite and ilmenite replacing rutile suggest incomplete re-equilibration. We investigated garnet and phengite crystals by electron probe and laser ablation-ICP-MS mapping. Major and trace element mapping reveals very complex mineral zoning in both minerals. In particular, high Ti content in phengite and increasing P and Zr contents in pyrope-rich garnet indicate that the studied rock underwent a HP-HT event. This is also supported by Zr in rutile thermometry that indicates temperatures well above the Barrovian metamorphism (T &gt; 700 &amp;#176;C). We combined detailed textural analysis with petrological-geochemical data and thermodynamic modelling to reconstruct the metamorphic evolution of the studied rock. We show that, thank to incomplete re-equilibration, the rock documents an evolution from prograde to UHP-HT peak (27 kbar and 800 &amp;#176;C) to retrograde (Barrovian) conditions (10 kbar and 620 &amp;#176;C). Noteworthy, peak metamorphic conditions of metapelite coincide with peak metamorphic conditions of the garnet metaperidotite. Lastly, geochemical evidence for minor wet melting of the studied metapelite at HP-HT conditions was recognized and is likely linked to the dehydration of chlorite to form garnet peridotite in the adjacent ultramafic body. We propose that metapelites and ultramafic rocks were coupled before subduction or at least in its early stage. This finding opens new scenarios for the geodynamic interpretation of the Cima Lunga unit. We propose that the ultramafic lenses at Cima di Gagnone were parts of the exhumed and serpentinised mantle emplaced at the hyper-extended European continental margin of the Piemont-Ligurian ocean. Slices of the margin were detached and tectonically mixed in the subduction channel. These new constraints call for re-evaluation of the paleogeographic position of the Adula-Cima Lunga nappe.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document