Callander Bay Complex, Ontario Canada
The Callander Bay Complex lies at the eastern end of Lake Nipissing and most of the complex lies beneath the water of Callander Bay. The complex is approximately 2.25 miles in diameter and consists of cone sheets of fenite and nepheline syenite, (Sage 1997).
Callander Bay is an eroded Proterozoic volcanic pipe formed by the violent, supersonic eruption of a deep-origin volcano. These volcanoes originate at least three times as deep as most other volcanoes, and the resulting magma that is pushed toward the surface is high in magnesium and volatile compounds such as water and carbon dioxide. As the body of magma rises toward the surface, the volatile compounds transform to gaseous phase as pressure is reduced with decreasing depth. This sudden expansion propels the magma upward at rapid speeds, resulting in a shallow supersonic eruption.
Callander Bay contains uncommon rocks such as nepheline syenite and carbonatite and the minerals: aegirine, amphibole, analcime, apatite, barite, biotite, calcite, cancrinite, chalcopyrite, chlorite, diopside, dolomite, fluorite, garnet, hematite, kaersutite, magnetite, muscovite, nepheline, olivine, perthite, pyrite, pyroxene and pyrrhotite. (Wikipedia)
Eyles, Nick. Road Rocks Ontario pp. 537 2013.
Geological Report 94 Geology of the North Bay Area Districts of Nipissing and Parry Sound S. B. LUMBERS 1971
Sage, R.P. Alkalic Rocks of the Sudbury Region, INSTITUTE ON 43rd ANNUAL MAY 6 -11, 1997