Locally, ultramafic rocks, lamprophyre diatremes
and carbonatites are present (Veretennikov et al.
are explosive type features related to later stages of intrusions and are commonly mineralised or related to mineralisation.
1986: On the growth of maars and diatremes
and its relevance to the formation of tuff-rings.
Several volcanic dykes and diatremes
occur in the Sydney region: e.
were emplaced at relatively low, non-magmatic temperatures and are thought to have churned and mixed violently.
This forward modeling eliminates the possibility of the presence of other geological causative bodies such as igneous intrusions, Maars, Diatremes
or sedimentary structures, leaving the model of an impact crater as the most probable phenomenon that could generate the circular structure.
1999, 2000), including the Kuuvvaluk ultramafic lamprophyre diatremes
(Madore et al.
Intrusive rocks consist of granodiorite, quartz porphyry, granite porphyry and related dike complexes, as well as dikes and diatremes
of basaltic composition which are spatially connected with the main mineralised structures of the Kontchotch ore field.
Samples from several of the outcropping bodies, which form a cluster of dykes and small diatremes
in the central part of the property, returned only a few microdiamonds, and are not now part of the focus for PXC.
In the Sydney region, igneous materials are also present in volcanic intrusions such as Jurassic dykes and diatremes
In the early 1960's some kimberlite diatremes
in Laramie County, Colorado and adjacent parts of Wyoming were found to be diamondiferous (Collins, 1982), and 327 carats' worth of small octahedral crystals were recovered in the early 1990's (Moore, 1997).
Both are qualified persons by NI43-101 definition, and are familiar with exploration for and experienced in discovery of diamond bearing kimberlite diatremes
in the Northwest Territories.