Tin Enrichment in Magmatic-Hydrothermal Environments Associated with Cassiterite Mineralization at Ardlethan, Eastern Australia: Insights from Rb-Sr and Sm-Nd Isotope Compositions in Tourmaline

2020 ◽  
Author(s):  
Patrick Carr ◽  
Marc D. Norman ◽  
Vickie C. Bennett ◽  
Phillip L. Blevin
Keyword(s):  
Parental Magma ◽  
Nd Isotope ◽  
Chemical Leaching ◽  
Hydrothermal Processes ◽  
Eastern Australia ◽  
Type Granite ◽  
Hydrothermal Environments ◽  
Afc Process ◽  
Geologic Processes ◽  
Highly Evolved

Abstract Primary cassiterite mineralization is often associated with highly evolved granites, but the magmatic and hydrothermal processes that produce these deposits are often difficult to decipher. In this study, we employed the chemical and Sr-Nd isotope compositions of tourmaline to monitor processes of Sn enrichment in the magmatic and hydrothermal stages of the Ardlethan granite (Australia) and its associated Sn deposits. Initial 87Sr/86Sr (0.710–0.717) and ɛNd (–5.0 to –1.0) values of late magmatic tourmalines indicate derivation of the Ardlethan granite via an assimilation-fractional crystallization (AFC) process in which incorporation of Ordovician sediment into an I-type granitic parental magma produced an enrichment of Sn at least 30 times over that of the assumed mafic-dominated igneous source of the granite. The rare earth element and Sn concentrations of tourmaline in the greisen deposits together with δ18O of coprecipitated quartz indicate that exsolution of a late-stage, Cl-rich fluid from the Ardlethan granite led to cassiterite mineralization in these deposits. In contrast the Fe/(Fe + Mg) and initial εNd (–9.2 to –12.9) compositions of tourmaline that coprecipitated with cassiterite in the large breccia pipes adjacent to the Ardlethan granite suggest that granite-derived fluids scavenged Sn by chemical leaching of an older S-type granite that hosts the pipes. This study shows that tourmaline can act as a robust monitor of key geologic processes in complex and dynamic magmatic-hydrothermal Sn systems and that its 87Sr/86Sr and ɛNd isotope compositions are especially useful for constraining the nature of magmatic and hydrothermal sources that contributed to these deposits.

scholarly journals Geochemistry and Sr, Nd isotopic composition of the Hronic Upper Paleozoic basic rocks (Western Carpathians, Slovakia)

2015 ◽  
Vol 66 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Jozef Vozár ◽  
Ján Spišiak ◽  
Anna Vozárová ◽  
Jakub Bazarnik ◽  
Ján Krái
Keyword(s):  
Basaltic Andesite ◽  
Parental Magma ◽  
Crustal Material ◽  
Nd Isotope ◽  
Upper Paleozoic ◽  
Three Samples ◽  
Original Magma ◽  
Basic Rocks ◽  
Nd Isotopic Composition ◽  
Heterogeneous Source

Abstract The paper presents new major and trace element and first Sr-Nd isotope data from selected lavas among the Permian basaltic andesite and basalts of the Hronicum Unit and the dolerite dykes cutting mainly the Pennsylvanian strata. The basic rocks are characterized by small to moderate mg# numbers (30 to 54) and high SiO2 contents (51-57 wt. %). Low values of TiO2 (1.07-1.76 wt. %) span the low-Ti basalts. Ti/Y ratios in the dolerite dykes as well as the basaltic andesite and basalt of the 1st eruption phase are close to the recommended boundary 500 between high-Ti and low-Ti basalts. Ti/Y value from the 2nd eruption phase basalt is higher and inclined to the high-Ti basalts. In spite of this fact, in all studied Hronicum basic rocks Fe2O3* is lower than 12 wt. % and Nb/La ratios (0.3-0.6) are low, which is more characteristic of low-Ti basalts. The basic rocks are characterized by Nb/La ratios (0.56 to 0.33), and negative correlations between Nb/La and SiO2, which point to crustal assimilation and fraction crystallization. The intercept for Sr evolution lines of the 1st intrusive phase basalt is closest to the expected extrusions age (about 290 Ma) with an initial 87Sr/86Sr ratio of about 0.7054. Small differences in calculated values ISr document a partial Sr isotopic heterogeneity source (0.70435-0.70566), or possible contamination of the original magma by crustal material. For Nd analyses of the three samples, the calculated values εCHUR (285 Ma) are positive (from 1.75 to 3.97) for all samples with only subtle variation. Chemical and isotopic data permit us to assume that the parental magma for the Hronicum basic rocks was generated from an enriched heterogeneous source in the subcontinental lithospheric mantle.

Intrusive metallogenic provinces in eastern Australia based on granite source and composition

1996 ◽  
Vol 87 (1-2) ◽  
pp. 281-290 ◽  
Author(s):  
Phillip L. Blevin ◽  
Bruce W. Chappell ◽  
Charlotte M. Allen
Keyword(s):  
Near Surface ◽  
Element Ratios ◽  
Source Regions ◽  
Deep Crust ◽  
Eastern Australia ◽  
Systematic Relationships ◽  
Magmatic Suite ◽  
Surface Geology ◽  
Granite Suite ◽  
Highly Evolved

ABSTRACT:Ore element ratios in intrusion-related mineralisation are in part a function of the relative oxidation state and degree of fractionation of the associated granite suite. A continuum from Cu-Au through W to Mo dominated mineralisation related to progressively more fractionated, oxidised I-type magmas can be traced within single suites and supersuites. Such systematic relationships provide strong evidence for the magmatic source of ore elements in granite-related mineral deposits and for the production of the observed ore element ratios dominantly through magmatic processes. The distribution of mineralised intrusive suites can be used to define a series of igneous metallogenic provinces in eastern Australia. In general, there is a correlated evolution in the observed metallogeny (as modelled based on the compatibility of ore elements during fractionation) with increasing degree of chemical evolution of the associated magmatic suite. This is from Cu-Au associated with chemically relatively unevolved magmas, through to Sn and Mo-rich mineralisation associated with highly evolved magmas that had undergone fractional crystallisation. Provinces recognised in that way do not necessarily correlate with the tectonostratigraphic boundaries defined by the near-surface geology, indicating that the areal distribution of some granite source regions in the deep crust is unrelated to upper crustal geology.

Geochemistry and Nd isotopes of the François Lake plutonic suite, Endako batholith: host and progenitor to the Endako molybdenum camp, central British Columbia

2001 ◽  
Vol 38 (4) ◽  
pp. 603-618 ◽  
Author(s):  
Joseph B Whalen ◽  
Robert G Anderson ◽  
Lambertus C Struik ◽  
Michael E Villeneuve
Keyword(s):  
British Columbia ◽  
Magma Chamber ◽  
Nd Isotopes ◽  
Crustal Component ◽  
High K ◽  
Type Granite ◽  
Porphyry Mo Deposit ◽  
T Values ◽  
Source Materials ◽  
Highly Evolved

The Endako low-F granodiorite-type porphyry Mo deposit is hosted by the Triassic to Eocene Endako batholith, which comprises five temporally distinct plutonic suites, only one of which is mineralized. Pre-mineralization suites range in composition from diorite to granodiorite. The synmineralization Jurassic–Cretaceous François Lake suite includes two granodiorite- to monzogranite-bearing subsuites. Postmineralization phases include the Eocene Sam Ross Creek monzogranite. The batholith spans a silica range of 44–80 wt.% and consists of metaluminous to slightly peraluminous, low- to high-K, I-type granitoids; the Sam Ross Creek phase is an A-type granite. Positive ε Nd(T) values (+1.1 to +7.2) indicate derivation predominately from juvenile source materials, but with variable input from an older crustal component. Evidence suggests generation of older plutonic suites in a juvenile arc-type setting and younger K-rich felsic suites via recycling of juvenile arc crust without significant mantle-derived contributions. Three distinct Mo-deposition events in the Endako camp are linked to repeated generations of oxidized, highly evolved monzogranitic phases (pre-ore dykes, aplitic Nithi and Casey intrusions) belonging to both François Lake subsuites. Late pre-ore dykes with "Casey-like" geochemical signatures, along with massive unmineralized Casey intrusions near the Endako deposit, could reflect repeated injections from an underlying magma chamber that remained molten during the youngest Mo-deposition event. A genetic link may exist between the Sam Ross Creek phase, a pluton with Climax-type granite characteristics, and Eocene kaolinite alteration in the Endako deposit. Also, potential exists for Eocene-age Climax-type Mo mineralization within the Endako mining camp.

Mesoscopic structures resulting from crystal accumulation and melt movement in granites

2008 ◽  
Vol 97 (4) ◽  
pp. 369-381 ◽  
Author(s):  
R. H. Vernon ◽  
S. R. Paterson
Keyword(s):  
Magma Chamber ◽  
Layered Intrusions ◽  
Host Magma ◽  
South Eastern ◽  
Interstitial Liquid ◽  
Eastern Australia ◽  
Type Granite ◽  
Crystal Accumulation ◽  
South Eastern Australia

AbstractSeveral mesosocopic structures are consistent with mechanical accumulation of crystals and movement of melt in granite magmas, as well as compaction and shear of crystal-melt aggregates, concentrations of microgranitoid enclaves indented by megacrysts, and concentrations of crystals of the same mineral with different crystallisation histories. Evidence for crystal and enclave accumulation is shown clearly in mafic and silicic layered intrusions (MASLI-type granite plutons), for example, the Kameruka Granodiorite, Bega Batholith, south-eastern Australia.Crystal accumulations with interstitial liquid may become mobile in a magma chamber, owing to instabilities in the host magma caused by seismic and replenishment events or thermal and buoyancy variations. This remobilised material may intrude other parts of the chamber, as well as earlier-formed cumulates and even wall-rocks, as dykes, tubes, troughs and pipes. Marked concentrations of accessory and mafic minerals may also develop in these structures. Interstitial melt may also be extracted from accumulated aggregates, intruding and disrupting the aggregates. Spectacular examples of these various structures are preserved in the Tuolumne Batholith, California. Detailed mechanisms for the formation of many of the structures are not well understood, though the formation of cumulates in vertical layers suggests that sorting and filter pressing during flow and resulting strain of crystal mushes may play important roles.

scholarly journals Petrology and mineralogy of the Ulaan Del Zr-Nb-REE deposit, Lake Zone, Western Mongolia

2020 ◽  
Vol 50 ◽  
pp. 45-62
Author(s):  
Sanjsuren Oyunbat
Keyword(s):  
Fine Grained ◽  
Late Cambrian ◽  
Hydrothermal Processes ◽  
Western Mongolia ◽  
Lake Zone ◽  
High K ◽  
Ore Minerals ◽  
Type Granite ◽  
Host Rocks ◽  
Syenite Porphyry

The Ulaan Del deposit is located in the Lake Zone, Western Mongolia. In the area, middle-late Devonian alkali dykes of the Khalzan Complex are hosted in the middle-late Cambrian granodiorite-tonalite of the Togthohiinshil Complex. The alkali dykes of the Khalzan complex comprise medium- to fine-grained syenite, microsyenite, syenite-porphyry and trachyte, trachyrhyolite, and trachyandesite. The dykes are replaced to silica, sericite, albite, fluorite and are brecciated. They crosscut by quartz and quartz-carbonate veinlets. The dykes contain zircon (>0.19% Zr) with a total of rare earth elements oxides >0.1%. The host rocks of the Togtokhiinshil complex are mid-K, metaluminous, I- type granite, depleted in HFSE. Based on geochemical and mineralogical data, economic REE mineralization is concentrated in syenite and syenite porphyry of calc-alkaline high K to shoshonite series of A- type granite, emplaced at within a plate setting. Syenite dykes are enriched in REE. Ore minerals are zircon, apatite, sphene, monazite, xenotime, synchysite, parisite, fluorite and REE complex minerals, pyrite, rutile and limonite. Magmatic, metasomatic and hydrothermal processes significantly contributed to the formation of Zr, Nb, REE and Y mineralization at the Ulaan Del deposit.

scholarly journals Whole-Rock Elemental and Sr-Nd Isotope Geochemistry and Petrogenesis of the Miocene Elmadağ Volcanic Complex, Central Anatolia (Ankara, Turkey)

Geosciences ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 348
Author(s):  
Kürşad Asan
Keyword(s):  
Mantle Source ◽  
Isotope Geochemistry ◽  
Parental Magma ◽  
Central Anatolia ◽  
Volcanic Complex ◽  
Major Element Composition ◽  
Nd Isotope ◽  
Basaltic Rocks ◽  
Zircon Crystallization ◽  
Felsic Rocks

This study presented whole-rock elemental and Sr-Nd isotope geochemistry data with the purpose to decipher the origin and evolution of the Miocene Elmadağ Volcanic Complex, Central Anatolia (Ankara, Turkey). Volcanic products spanned in composition from mildly alkaline basaltic (47–52 wt% SiO2) and medium- to high-K calc-alkaline intermediate (54–62 wt% SiO2; andesite to trachyandesite) to felsic (64–74 wt% SiO2; dacite to rhyolite) units. Despite a homogeneous major element composition, basaltic rocks were characterized by two distinct trace element and isotopic signatures, which have been correlated with different mantle sources. The first group of basaltic rocks was similar to those of oceanic island basalts (OIB) and was derived from asthenospheric mantle source. The second group had geochemical characteristics of orogenic basalts derived from subduction-modified lithospheric mantle source and represented parental magma of the intermediate to felsic rocks. By coupling geochemical and textural analyses of the rocks from the Elmadağ Volcanic Complex, I suggest that crystallization of olivine + clinopyroxene + apatite played an important role in the evolution of basaltic rocks, while plagioclase + amphibole + apatite + Fe-Ti oxides ± zircon crystallization was major process involved in the evolution of intermediate to felsic rocks. The EVC basaltic rocks were associated with the post-collisional extensional tectonic regime in the Central Anatolia, but the coexistence of the OIB-like volcanism implies variations in the extension dynamics during Miocene.

scholarly journals Crystallization and destabilization of eudialyte-group minerals in peralkaline granite and pegmatite: a case study from the Ambohimirahavavy complex, Madagascar

2018 ◽  
Vol 82 (2) ◽  
pp. 375-399 ◽  
Author(s):  
Guillaume Estrade ◽  
Stefano Salvi ◽  
Didier Béziat
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Parental Magma ◽  
Accessory Minerals ◽  
Eudialyte Group ◽  
Peralkaline Granite ◽  
Rich Material ◽  
Highly Evolved

AbstractEudialyte-group minerals (EGM) are very common in highly evolved SiO2-undersaturated syenites and are characteristic minerals of agpaitic rocks. Conversely, they are extremely rare in peralkaline granites, with only a handful of EGM occurrences reported worldwide. Here, we study two new examples of EGM occurrence in two types of peralkaline pegmatitic granites from the Cenozoic Ambohimirahavavy complex, and assess the magmatic conditions required to crystallize EGM in peralkaline SiO2-oversaturated rocks. In the transitional granite (contains EGM as accessory minerals) EGM occur as late phases and are the only agpaitic and major rare-earth element (REE) bearing minerals. In the agpaitic granite (contains EGM as rock-forming minerals) EGM are early-magmatic phases occurring together with two other agpaitic minerals, nacareniobsite-(Ce) and turkestanite. In these granites, EGM are partly-to-completely altered and replaced by secondary assemblages consisting of zircon and quartz in the transitional granite and an unidentified Ca-Na zirconosilicate in the agpaitic granite. Ambohimirahavavy EGM, as well as those from other peralkaline granites and pegmatites, are richer in REE and poorer in Ca than EGM in nepheline syenites. We infer that magmatic EGM are rare in SiO2-oversaturated rocks because of low Cl concentrations in these melts. At Ambohimirahavavy, contamination of the parental magma of the agpaitic granite with Ca-rich material increased the solubility of Cl in the melt promoting EGM crystallization. In both granite types, EGM were destabilized by the late exsolution of a fluid and by interaction with an external Ca-bearing fluid.

scholarly journals Intensive low-temperature tectono-hydrothermal overprint of peraluminous rare-metal granite: a case study from the Dlhá dolina valley (Gemericum, Slovakia)

2015 ◽  
Vol 66 (1) ◽  
pp. 19-36 ◽  
Author(s):  
Karel Breiter ◽  
Igor Broska ◽  
Pavel Uher
Keyword(s):  
Low Temperature ◽  
Large Body ◽  
Rare Metal ◽  
Biotite Granite ◽  
Small Scale ◽  
In Situ Forming ◽  
Type Granite ◽  
Compositional Variations ◽  
Highly Evolved

Abstract A unique case of low-temperature metamorphic (hydrothermal) overprint of peraluminous, highly evolved rare-metal S-type granite is described. The hidden Dlhá dolina granite pluton of Permian age (Western Carpathians, eastern Slovakia) is composed of barren biotite granite, mineralized Li-mica granite and albitite. Based on whole-rock chemical data and evaluation of compositional variations of rock-forming and accessory minerals (Rb-P-enriched K-feldspar and albite; biotite, zinnwaldite and di-octahedral micas; Hf-(Sc)-rich zircon, fluorapatite, topaz, schorlitic tourmaline), the following evolutionary scenario is proposed: (1) Intrusion of evolved peraluminous melt enriched in Li, B, P, F, Sn, Nb, Ta, and W took place followed by intrusion of a large body of biotite granites into Paleozoic metapelites and metarhyolite tuffs; (2) The highly evolved melt differentiated in situ forming tourmaline-bearing Li-biotite granite at the bottom, topaz-zinnwaldite granite in the middle, and quartz albitite to albitite at the top of the cupola. The main part of the Sn, Nb, and Ta crystallized from the melt as disseminated cassiterite and Nb-Ta oxide minerals within the albitite, while disseminated wolframite appears mainly within the topaz-zinnwaldite granite. The fluid separated from the last portion of crystallized magma caused small scale greisenization of the albitite; (3) Alpine (Cretaceous) thrusting strongly tectonized and mylonitized the upper part of the pluton. Hydrothermal low-temperature fluids enriched in Ca, Mg, and CO2 unfiltered mechanically damaged granite. This fluid-driven overprint caused formation of carbonate veinlets, alteration and release of phosphorus from crystal lattice of feldspars and Li from micas, precipitating secondary Sr-enriched apatite and Mg-rich micas. Consequently, all bulk-rock and mineral markers were reset and now represent the P-T conditions of the Alpine overprint.

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