Eudialyte

Location: Alaska, United States (62.064, -154.084 approx.)

Commodities: rare earth elements; zirconium; thorium; uranium

Deposit model: REE-Th bearing veins · Th-REE veins

Geology

The early Tertiary MFPC consists of coeval syenite, peralkaline alkali feldspar granite, metaluminous granite, diorite, and gabbro, hosted by a thinly bedded Paleozoic calc-phyllites and marbles. The eudialyte-bearing specimen was found in talus in the contact zone between cogenetic fayalite-hedenbergite-syenite and peralkaline alkali feldspar granite near the southern margin of the plutonic complex. Metasedimentary host-rock comprises part of the specimen and suggests that the eudialyte is in a dyke which intruded the country rock near the southern contact of the MFPC. There is little or no quartz in the sample, implying a closer genetic relationship with syenite than with adjacent peralkaline granite. Two distinct populations of eudialyte were separated from the sample based upon color differences (pink and brown). In addition to about 5 percent eudialyte, the mineralogy includes alkali feldspar (some with microcline twinning), clinopyroxene, aenigmatite, minor plagioclase, and carbonate. (Gunter and others (1993))

Record imported from USGS USMIN ver. 4.0 (June 2019). Developments after that date appear on facility records, not here; see the methodology.