Mineralogy and petrology of the Good Hope carbonatite complex, Marathon, Ontario
Abstract
The Good Hope carbonatite is located northwest of Marathon, Ontario (49° 02’ N, 86°
43’ W). It occurs along the northwest margin of the Prairie Lake complex. The objectives of this
research are to characterize the carbonate and other minerals of the Good Hope carbonatite,
use mineral compositions and textural associations to discuss the petrogenesis, and compare
the mineralogy of the Good Hope and Prairie Lake carbonatites to assess potential
relationships.
The major rock-forming minerals in the Good Hope carbonatite are calcite, ferroan
dolomite, and apatite. The apatite occurs predominantly as elongated aggregates and clasts
that define heterogeneous banding within the carbonatite. Syenite xenoliths are centimeterscale, entrained within the carbonatite, composed of K-feldspar, biotite-phlogopite, magnesioarfvedsonite, aegirine, quartz, and carbonate. The minor minerals within the carbonatite
include dolomite, K-feldspar, quartz, chlorite, magnetite, barite, biotite – phlogopite, magnesioarfvedsonite, aegirine, pyrochlore, albite, and fluorite. The accessory minerals include pyrite,
synchysite-(Ce), rutile, siderite, strontianite, thorite, parisite-(Ce), bastnaesite-(Ce), burbankite,
and zircon. [...]