It is also older than ages reported for lamprophyre
dykes elsewhere in central and southeastern New England, and if correct, indicates that alkaline magmatism in
The size of the samples and the lateral distribution of the locations indicate that diamonds in lamprophyres
are widespread in the region and that further exploration may yield some positive finds, Calhoun said in a press release.
With a zone occurrence about three kilometres long and a kilometre wide; the rocks being targeted are considered to be a very rare find of xenolith-bearing lamprophyre
occurring in a volcanic breccia.
A NATMAP project in 1995 located at least eight so-called ultramafic lamprophyre
dykes in the Cape Chidley area of northernmost Labrador and Nunavut.
This area lies on the northern extension of the Trans-Superior Tectonic Zone (TSTZ), which encloses kimberlites and kimberlite-like ultramafic lamprophyre
dykes in Michigan.
The diamond was recovered by caustic dissolution of a biotite-rich lamprophyre
dyke collected by Ontario Ministry of Northern Development and Mines District Geologist Mr.
These black garnets are commonly found in the magmatic phase of ultramafic lamprophyres
and were found in a Le Tac field kimberlitoid rock and also in the Selco field in Northern Ontario.
The presence of gabbro and sheared lamprophyres
was also observed in the blasted trench.
are xenolith bearing, similar to diamondiferous dykes currently being explored in the Wawa area of Ontario.
Locally ore controls may vary but the shearing control, with widening in flexure features is obiquitous, host rocks, predominantly metasediments, may vary to lamprophyres
, porphyry or ultra-basics.
These northeast faults are thought to be deep-seated mineralizing features because of the presence of lamprophyre
style intrusions and altered and mineralized fragments of lamprophyres
and limestone in the explosive hydrothermal breccias located along them.
The drilling will test two separate targets - diamond bearing lamprophyre
dykes and high grade silver/cobalt veins.