Characterization of biotite and amphibole compositions in granites

Gion, Austin M.; Piccoli, Philip M.; Candela, Philip A.

doi:10.1007/s00410-022-01908-7

Cited by 16 publications

(4 citation statements)

References 52 publications

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“…The relative oxygen fugacities of amphibole crystallization, can be calculated according to the model of Ridolfi et al (2010), which yielded f O 2 = −12.78 to −11.67, ΔNNO = −0.06 to +1.78 for quartz diorite; f O 2 = −12.94 to −11.36, ΔNNO = −0.45 to +0.97 for granodiorite, and f O 2 = −12.73 to −12.45, ΔNNO = −0.79 to −0.49 for leucogranite magmas (Table 1). The predictive model of redox condition for biotite in felsic melts can be constrained using a random forest technique as recently propounded by Gion et al (2022). The mole fraction of X annite , X OH (empirically estimated), and Al t apfu of biotites from the LPC granitoids are projected on experimentally determined isobaric curve (200 MPa) (after Czamanske & Wones, 1973) at a given temperature, pressure and f O 2 (Figure 11).…”

Section: Discussionmentioning

confidence: 99%

“…Biotites from LPC granitoids are plotted in terms of X annite ‐X OH ‐Al t . The isothermal lines (200 MPa) and activity of magnetite and sanidine at different T ‐ f O 2 are set to 0.7 and 0.8, respectively (after Gion et al, 2022). The colored scale bar represents the content of total aluminium (Al t apfu) where scale 1 to 1.8 is color coded from purple (lowest Al t ) to red (highest Al t ).…”

Section: Discussionmentioning

confidence: 99%

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Magnetic susceptibility, mineral chemistry, and geothermobarometry of granitoids from Lohit Plutonic Complex, Arunachal Trans‐Himalaya, Northeast India: Implications on emplacement and crystallization conditions of oxidized calc alkaline magmatic arc system

et al. 2023

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The Lohit Plutonic Complex (LPC) of Arunachal Trans‐Himalaya represents the northeast extension of Trans‐Himalayan magmatic arc system located in the north of Indus Tsangpo Suture Zone (ITSZ). Field relation, magnetic susceptibility (MS), and phase petrology on the granitoids of LPC was conducted in order to assess the granite series (magnetite, oxidized vs. ilmenite, reduced types), and physico‐chemical conditions of the LPC granitoid magmas. The studied granitoids are well‐exposed in the Dibang and Lohit valleys, and their MS values indicate a bi‐modal patterns corresponding to ilmenite (reduced) series (71%) and magnetite (oxidized) series (29%) granites. The variation of MS in the LPC granitoids is related to the alteration of ferromagnetic minerals, and later tectonic and deformational processes that acted upon them. The amphiboles from the LPC granitoids are calcic (CaB >1.5, Si = 6.30–7.06 apfu) and exhibit tschermak substitutions typical to their evolution in a calc alkaline, metaluminous (I‐type) felsic magmas. Al‐in‐hornblende rims estimate the emplacement of quartz diorite and granodiorite magmas at shallow (~5 km) and mid (~16 km) crustal depths. Geothermometric results point to a regime of magmatic crystallization (940–837°C for quartz diorite; 882–829°C for granodiorite) sufficiently above the solidus of respective melts. Biotites from LPC granitoids are primary to re‐equilibrated, and transitional between magnesio‐ and ferri‐biotites. Quartz diorite and granodiorite biotites evolved under oxidizing magmas (log ƒO2−14 to log ƒO2−13) in a temperature range of ~750–950°C, typical to their formation in a calc alkaline magma of subduction zone environment. However, the biotites from leucogranite appear to have evolved under a mildly reducing magma environment, most likely attained in a collisional setting. The obtained results suggest that the oxidized nature of calc alkaline, subduction‐related magmatic arc rocks of the LPC is largely modified and reduced by post‐magmatic, and later tectonothermal and deformational events that operated during Himalayan and Trans‐Himalayan orogenesis.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Magnetic susceptibility, mineral chemistry, and geothermobarometry of granitoids from Lohit Plutonic Complex, Arunachal Trans‐Himalaya, Northeast India: Implications on emplacement and crystallization conditions of oxidized calc alkaline magmatic arc system

et al. 2023

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“…In recent years, it has been successfully applied to a diverse suite of classification challenges on high-dimensional datasets in the geosciences (Petrelli & Perugini, 2016;Schönig et al, 2021;Zhong et al, 2021;Wang et al, 2022). These include estimating pre-eruptive temperatures and pressures using clinopyroxene-melt (Petrelli et al, 2020), evaluating the occurrence of H diffusion in the clinopyroxene phenocrysts of basaltic magma (Chen et al, 2021), proposing and improving thermobarometry for different magma types (biotite-bearing magma: Li and Zhang, 2022, amphibole -bearing magma: Higgins et al, 2022, clinopyroxene-bearing magma: Jorgenson et al, 2022, and distinguishing S-, I-, and A-type granites (Gion et al, 2022).…”

Section: Diagnostic Geochemical Signatures From Apatite Trace Element...mentioning

confidence: 99%

Apatite trace element composition as an indicator of ore deposit types: A machine learning approach

Qiu,

Zhou,

Chew

et al. 2024

American Mineralogist

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The diverse suite of trace elements incorporated into apatite in ore-forming systems has important applications in petrogenesis studies of mineral deposits. Trace element variations in apatite can be used to distinguish between fertile and barren environments, and thus have potential as mineral exploration tools. Such classification approaches commonly employ two-variable scatterplots of apatite trace element compositional data. While such diagrams offer accessible visualization of compositional trends, they often struggle to effectively distinguish ore deposit types because they do not employ all the high-dimensional (i.e. multi-element) information accessible from high-quality apatite trace element analysis. To address this issue, we use a supervised machine learning-based approach (eXtreme Gradient Boosting, XGBoost) to correlate apatite compositions with ore deposit type, utilizing such highdimensional information. We evaluated 8629 apatite trace element data from five ore deposit types (porphyry, skarn, orogenic Au, iron oxide copper gold, and iron oxideapatite) along with unmineralized magmatic and metamorphic apatite to identify discriminating parameters for the individual deposit types as well as for mineralized systems. According to feature selection, eight elements (Th, U, Sr, Eu, Dy, Y, Nd and La) improve the model performance. We could show that the XGBoost classifier efficiently and accurately classifies high-dimensional apatite trace element data according to the ore deposit type (overall accuracy: 94% and F1 score: 89%).Interpretation of the model using the SHAPley Additive exPlanations (SHAP) tool shows that Th, U, Eu and Nd are the most indicative elements for classifying deposit types using apatite trace element chemistry. Our approach has broad implications for the better understanding of the sources, chemistry and evolution of melts and hydrothermal fluids resulting in ore deposit formation.

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“…Although there are a plethora of major-element data in the literature (e.g. Leake, 1968; Gion et al , 2022), there are few studies of the trace-element compositions of amphibole. Previous studies have focused on the trace-element composition of amphibole in igneous rocks with only a very limited number focusing on amphibole in metamorphic rocks (e.g.…”

Section: Mineral Compositionmentioning

confidence: 99%

The trace-element compositions of amphibole, magnetite and ilmenite as potential exploration guides to metamorphosed Proterozoic Cu–Zn±Pb±Au±Ag volcanogenic massive sulfide deposits in Colorado, USA

Spry,

Berke,

Layton-Matthews

et al. 2023

MinMag

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Orthoamphibole, clinoamphibole and magnetite are common minerals in altered rocks associated spatially with Palaeoproterozoic volcanogenic massive sulfide (VMS) deposits in Colorado, USA and metamorphosed to the amphibolite facies. These altered rocks are dominated by the assemblage orthoamphibole (anthophyllite/gedrite)–cordierite–magnetite±gahnite±sulfides. Magnetite also occurs in granitoids, banded iron formations, quartz garnetite, and in metallic mineralisation consisting of semi-massive pyrite, pyrrhotite, chalcopyrite, and sphalerite with subordinate galena, gahnite and magnetite; amphibole also occurs in amphibolite. The precursor to the anthophyllite/gedrite–cordierite assemblages was probably the assemblage quartz–chlorite formed from hydrothermal ore-bearing fluids (~250° to 400°C) associated with the formation of metallic minerals in the massive sulfide deposits. Element–element variation diagrams for amphibole, magnetite and ilmenite based on LA-ICP-MS data and Principal Component Analysis (PCA) for orthoamphiboles and magnetite show a broad range of compositions which are primarily dependent upon the nature of the host rock associated spatially with the deposits. Although discrimination plots of Al/(Zn+Ca) vs Cu/(Si+Ca) and Sn/Ga vs Al/Co for magnetite do not indicate a VMS origin, the concentration of Al+Mn together with Ti+V and Sn vs Ti support a hydrothermal rather than a magmatic origin for magnetite. Principal Component Analyses also show that magnetite and orthoamphibole in metamorphosed altered rocks and sulfide zones have distinctive eigenvalues that allow them to be used as prospective pathfinders for VMS deposits in Colorado. This, in conjunction with the contents of Zn and Al in magnetite, Zn and Pb in amphibole, ilmenite and magnetite, the Cu content of orthoamphibole and ilmenite, and possibly the Ga and Sn concentrations of magnetite constitute effective exploration vectors.

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Characterization of biotite and amphibole compositions in granites

Cited by 16 publications

References 52 publications

Magnetic susceptibility, mineral chemistry, and geothermobarometry of granitoids from Lohit Plutonic Complex, Arunachal Trans‐Himalaya, Northeast India: Implications on emplacement and crystallization conditions of oxidized calc alkaline magmatic arc system

Magnetic susceptibility, mineral chemistry, and geothermobarometry of granitoids from Lohit Plutonic Complex, Arunachal Trans‐Himalaya, Northeast India: Implications on emplacement and crystallization conditions of oxidized calc alkaline magmatic arc system

Apatite trace element composition as an indicator of ore deposit types: A machine learning approach

The trace-element compositions of amphibole, magnetite and ilmenite as potential exploration guides to metamorphosed Proterozoic Cu–Zn±Pb±Au±Ag volcanogenic massive sulfide deposits in Colorado, USA

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