Next Article in Journal
Evidence for Nb-Ta Occurrences in the Syn-Tectonic Pan-African Mayo Salah Leucogranite (Northern Cameroon): Constraints from Nb-Ta Oxide Mineralogy, Geochemistry and U-Pb LA-ICP-MS Geochronology on Columbite and Monazite
Next Article in Special Issue
Age and Origin of Monazite Symplectite in an Iron Oxide-Apatite Deposit in the Adirondack Mountains, New York, USA: Implications for Tracking Fluid Conditions
Previous Article in Journal
Geometallurgical Study of a Gravity Recoverable Gold Orebody
Article

Dating Metasomatism: Monazite and Zircon Growth during Amphibolite Facies Albitization

1
Department of Earth, Environmental and Planetary Sciences, Rice University, Houston 77005, TX, USA
2
Department of Geological Sciences, University of Colorado, Boulder 80309, CO, USA
3
Department of Geology, The University of Kansas, Lawrence 66045, KS, USA
*
Author to whom correspondence should be addressed.
Minerals 2018, 8(5), 187; https://doi.org/10.3390/min8050187
Received: 24 March 2018 / Revised: 20 April 2018 / Accepted: 24 April 2018 / Published: 29 April 2018
We present coupled textural observations and trace element and geochronological data from metasomatic monazite and zircon, to constrain the timing of high-grade Na-metasomatism (albitization) of an Archean orthogneiss in southwest Montana, USA. Field, mineral textures, and geochemical evidence indicate albitization occurred as a rind along the margin of a ~3.2 Ga granodioritic orthogneiss (Pl + Hbl + Kfs + Qz + Bt + Zrn) exposed in the Northern Madison range. The metasomatic product is a weakly deformed albitite (Ab + Bt + OAm + Zrn + Mnz + Ap + Rt). Orthoamphibole and biotite grew synkinematically with the regional foliation fabric, which developed during metamorphism that locally peaked at upper amphibolite-facies during the 1800–1710 Ma Big Sky orogeny. Metasomatism resulted in an increase in Na, a decrease in Ca, K, Ba, Fe, and Sr, a complete transformation of plagioclase and K-feldspar into albite, and loss of quartz. In situ geochronology on zoned monazite and zircon indicate growth by dissolution–precipitation in both phases at ~1750–1735 Ma. Trace element geochemistry of rim domains in these phases are best explained by dissolution–reprecipitation in equilibrium with Na-rich fluid. Together, these data temporally and mechanistically link metasomatism with high-grade tectonism and prograde metamorphism during the Big Sky orogeny. View Full-Text
Keywords: metasomatism; albitization; geochronology; trace element geochemistry; monazite; zircon; SW Montana metasomatism; albitization; geochronology; trace element geochemistry; monazite; zircon; SW Montana
Show Figures

Figure 1

MDPI and ACS Style

Condit, C.B.; Mahan, K.H.; Curtis, K.C.; Möller, A. Dating Metasomatism: Monazite and Zircon Growth during Amphibolite Facies Albitization. Minerals 2018, 8, 187. https://doi.org/10.3390/min8050187

AMA Style

Condit CB, Mahan KH, Curtis KC, Möller A. Dating Metasomatism: Monazite and Zircon Growth during Amphibolite Facies Albitization. Minerals. 2018; 8(5):187. https://doi.org/10.3390/min8050187

Chicago/Turabian Style

Condit, Cailey B., Kevin H. Mahan, Kelly C. Curtis, and Andreas Möller. 2018. "Dating Metasomatism: Monazite and Zircon Growth during Amphibolite Facies Albitization" Minerals 8, no. 5: 187. https://doi.org/10.3390/min8050187

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop