Versatile monazite

I study a wide variety of accessory minerals. These are not found in abundance rocks, but because of their compositions and presence, can be used to track a wide range of geological processes. One mineral that has been the focus of my research is monazite, rare-earth phosphate mineral (Ce,La,Th)PO4. This mineral is an important ore of the rare earth elements, used in a wide variety of emerging technology. Because of its high radioactive element content, it can also be used to time geological processes related to its crystallization.

Monazite is often found in nature as a complexly zoned mineral. I study the best approaches to interpret monazite ages and try to understand why and how monazite chemistry can be used to explain its ages. Chemical variations can create misleading expectations regarding its number of growth stages, and thus the number of temporally distinct tectonic episodes the mineral, rock, or region experienced and recorded.

In addition, monazite composition, zoning, and even its shape have been suggested to identify its origin in specific rock types. The distribution of particular elements in monazite, like Y, Th, and rare earth elements as a tool to discriminate for it origin would be beneficial. I have explored correlations between monazite chemistry, zoning, shape, and provenance and often test some of these generalizations. If I find the mineral in my field areas, I date it and apply its ages to understand how the geology of the region changed over time.

Collaborators

• Nathan Miller, Dept. Geological Sciences, UT Austin

• Ibrahim Cemen, Dept. Geological Sciences, University of Alabama

• Mark Harrison, Dept. Earth, Planetary, and Space Sciences, UCLA

Peer-reviewed publications regarding this work:

Catlos EJ, Miller NR (2017) Speculations Linking Monazite Compositions to Origin: Llallagua Tin Ore Deposit (Bolivia). For Special Issue “Criticality of the Rare Earth Elements: Current and Future Sources and Recycling.” Resources, 6(3), 36; doi:10.3390/resources6030036

Catlos EJ, Miller NM (2016) Ion microprobe 232Th208Pb ages from the high common Pb Amelia pegmatite monazite, Virginia: Implications for Alleghanian tectonics. American Journal of Science, 316, 470-503.

Catlos EJ (2013) Generalizations about monazite: Implications for geochronologic studies. American Mineralogist, 98:819-832. DOI: 10.2138/am.2013.4336. [Notable Paper Award from the journal]

Catlos EJ, Baker CB, Cemen I, Ozerdem C (2008) Whole rock major element influences on monazite growth: examples from igneous and metamorphic rocks in the Menderes Massif, western Turkey. Mineralogia, 38, 5-18. [INVITED PAPER for 1st issue of the journal]

Catlos EJ, Dubey CS, Sivasubramanian P (2008) Monazite ages from carbonatites and high grade assemblages along the Kambam Fault (Southern Granulite Terrain, South India). American Mineralogist, 93, 1230-1244.

Catlos EJ, Cemen I (2005) Monazite ages and the evolution of the Menderes Massif, western Turkey. International Journal of Earth Sciences, 94, 204-217.

Catlos, E.J., Gilley, L.D., Harrison, T.M. (2002) Interpretation of monazite ages obtained via in situ analysis. Chemical Geology, 188, 193-215.