Incongruent dissolution of REE- and Sr-rich apatite in peraluminous granitic liquids; differential apatite, monazite, and xenotime solubilities during anatexis

Wolf, Michael B.; London, David

doi:10.2138/am-1995-7-814

Cited by 145 publications

(60 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result is consistent with numerous other studies that have demonstrated limited REE mobility during reaction of phosphate minerals with hydrothermal fluids (e.g. Harlov and Förster 2004) or melts (Wolf and London 1995), and also validates the use of the Sm-Nd isotope composition of REE mineral pairs to construct meaningful isochrons for the timing of brecciation (Fig. 12).…”

Section: Bx2 and Bx3supporting

confidence: 91%

Genesis of the central zone of the Nolans Bore rare earth element deposit, Northern Territory, Australia

Schoneveld

Spandler

Hussey³

2015

Contrib Mineral Petrol

View full text Add to dashboard Cite

north and south-east zones. Breccia types BX2, BX3, and BX4 represent progressive stages of ore brecciation and development of calc-silicate mineral (amphibole, epidote, allanite, calcite) infill. Comparison of bulk ore sample geochemistry between breccia types indicates that REEs were not mobilised more than a few centimetres during hydrothermal alteration and brecciation. Instead, most of the REEs were partitioned from the original REE fluorapatite into newly formed allanite, REE-poor fluorapatite and minor REE carbonate in the breccias. Negative europium (Eu) anomalies in the breccia minerals are accounted for by a large positive Eu anomaly in epidote from the alteration zones surrounding the ore breccias. This observation provides a direct link between ore recrystallisation and brecciation, and the formation of the alteration halo in the surrounding host rocks. Where allanite and fluorapatite are texturally related, the fluorapatite is relatively depleted in the light rare earth elements (LREEs), whereas allanite is relatively LREE enriched, suggesting co-crystallisation. We tentatively date the BX1 ore stage to 1440 ± 80 Ma based on U-Pb dating of thorianite. Sm-Nd isotope isochrons derived from in situ isotope analysis of cognate apatite and allanite date the BX2 and BX3 events to ca. 400 Ma, while U-Pb dating of late-stage monazite from the BX4 ore stage returned an age of ca. 350 Ma. Therefore, formation of the central zone at Nolans Bore involved multiple alteration/brecciation events that collectively span over 1 billion years in duration. We suggest that the BX1-type veins and breccias were formed from REE-rich, saline (Fand Cl-bearing) fluids that infiltrated the granulite-grade host rocks in association with either shear activation events of the Redbank Shear Zone (1500-1400 Ma) or intrusion of late-stage pegmatites of the Mt Boothby area. BX2, BX3, and BX4 events record deformation and hydrothermal alteration associated with the Alice Springs Orogeny Abstract The Nolans Bore rare earth element (REE) deposit consists of a network of fluorapatite-bearing veins and breccias hosted within Proterozoic granulites of the Reynolds Range, Central Australia. Mineralisation is divided into three zones (north, central, and south-east), with the north and south-east zones consisting of massive REE-bearing fluorapatite veins, with minor brecciation and carbonate infill. The central zone is distinctively different in mineralogy and structure; it features extensive brecciation, a high allanite content, and a large, epidote-rich enveloping alteration zone. The central zone is a reworking of the original solid apatite veins that formed during the Chewings Orogeny at ca. 1525 Ma. These original apatite veins are thought to derive from phosphate-rich magmatic-hydrothermal fluid exsolved from as-yet unrecognised alkaline magmatic bodies at depth. We define four ore breccia types (BX1-4) in the central zone on the basis of detailed petrological and geochemical analysis of drillcore and thin sections. BX1 ore comprises fl...

show abstract

Section: Bx2 and Bx3supporting

confidence: 91%

Genesis of the central zone of the Nolans Bore rare earth element deposit, Northern Territory, Australia

Schoneveld

Spandler

Hussey³

2015

Contrib Mineral Petrol

View full text Add to dashboard Cite

show abstract

“…It could be used specifically in igneous rocks to distinguish between monazite formed by incongruent dissolution of apatite during rock anatexis (e.g. Wolf and London, 1995) and monazite grown from a melt. The latter commonly contain Th in excess of 2 -4 wt.% (e.g.…”

Section: Discussion and Geological Implicationsmentioning

confidence: 99%

Monazite-(Ce)-huttonite solid solutions in granulite-facies metabasites from the Ivrea-Verbano Zone, Italy

Förster

1999

Mineral. mag.

View full text Add to dashboard Cite

Composite populations of monazite-group minerals of both metamorphic and metasomatic origin have been discovered in thin layers of granulite-facies metabasites interlayered with metapelites, located in the Val Strona di Omegna region of the Ivrea-Verbano Zone, Italy. In addition to monazite-(Ce), which is uncommonly poor in Th and is probably formed by incongruent dissolution of apatite, these populations include members of the monazite~uttonite series. The latter minerals contain between 13 and 30.1 mol.% ThSiO4 [= huttonitic monazite-(Ce)], and are known from only half a dozen other occurrences worldwide. We propose that breakdown of primary monazite-(Ce) in the metapelites during granulite-facies metamorphism mobilized Th and the REEs, which were then transported by high-grade metamorphic fluids into the metabasite layers to form the Th-rich minerals of the monazitehuttonite series.

show abstract

“…These results provide a basis from which the effects of accessory phases on the fractionation of LREEs, particularly Sm from Nd, can be understood. Unfortunately, almost all the experimentally determined partial melting reactions have focused on rockforming minerals, and do not report the behavior of key accessory phases, even though a number of studies have indicated the importance of accessory minerals in controlling the LREE, trace and some major elements (e.g., phosphorus and titanium) of crustally derived melts (Sawyer, 1991;Sevigny, 1993;Watt and Harley, 1993;Nabelek and Glascock, 1995;Wolf and London, 1995;Watt et al, 1996). Hence we must attempt to combine information from separate sets of experiments on major-mineral melting reactions and accessory mineral solubility and dissolution kinetics; if we can identify common variables that affect both systems, we can predict the coupling of these processes even though few experimental studies have examined them simultaneously.…”

Section: Dissolution Of Accessory Mineralsmentioning

confidence: 99%

Coupling of anatectic reactions and dissolution of accessory phases and the Sr and Nd isotope systematics of anatectic melts from a metasedimentary source

Zeng

Asimow

Saleeby

2005

Geochimica et Cosmochimica Acta

148

View full text Add to dashboard Cite

Incongruent dissolution of REE- and Sr-rich apatite in peraluminous granitic liquids; differential apatite, monazite, and xenotime solubilities during anatexis

Cited by 145 publications

References 35 publications

Genesis of the central zone of the Nolans Bore rare earth element deposit, Northern Territory, Australia

Genesis of the central zone of the Nolans Bore rare earth element deposit, Northern Territory, Australia

Monazite-(Ce)-huttonite solid solutions in granulite-facies metabasites from the Ivrea-Verbano Zone, Italy

Coupling of anatectic reactions and dissolution of accessory phases and the Sr and Nd isotope systematics of anatectic melts from a metasedimentary source

Contact Info

Product

Resources

About