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
Kaersutite separated from lamprophyres
CR 574 and SE 78 yield mean ages of 165.
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.
Deformations of lamprophyre
dykes 28-26 Ma in age along a NW-SE-striking transtensional zone related to this fault are visible in the Techlovice quarries (Cajz and Adamovic, 2003) and correspond to E-W extension.
Emplacement and evolution of intermediate to basic dyke rocks and lamprophyres
in this part of the Bohemian Massif were characterised by Nemec (1970, 1974), Vrana et al.
A classification and nomenclature of volcanic rocks, lamprophyres
and melilitic rocks: Recommendations and suggestion of the IUGS on the Systematic of igneous Rocks.
1999): Mafic precursors, peraluminous granitoids, and late lamprophyres
in the Avila batholith; a model for the generation of Variscan batholiths in Iberia.
A common feature of the lamprophyres
noted by Hodgson (1968) is the formation of loose spheroids on weathered surfaces caused by the presence of coarse-grained, feldspar-rich ocelli [= eyes in Latin] which are more weather-resistant than the finer-grained matrix.
It consists of alkaline lamprophyres
that are considered volatile-enriched equivalents of alkali basalts (Rock, 1991, p.
The rocks are very similar in appearance, age and geological setting to the diamond bearing lamprophyres
and volcanic breccias under development for diamonds 400 kiometres away, in the Wawa area on the eastern shores of Lake Superior.
1979: Classification y nomenclature of volcanic rocks, lamprophyres
, carbonatites, and melilitic rocks: recommendations and suggestions of the IUGS Subcommission on the Systematics of Igneous Rocks.
3], and (4) olivine with Fo contents of ~88-92 (some of the lamprophyres
have two populations of olivine with clusters of similar high Fo values).