41. The floral assemblages associated with highly nickeliferous ultramafic rocks are indicative tools for mineral exploration. 42. There are bands of ultramafic rock near the Missisquoi River valley, and basalt also occurs. 43. Ultramafic rocks also contain elevated amounts of chromium and nickel which may be toxic to plants.44. Thus, ultramafic rocks have high Sm and low Nd and therefore " high" 45. Ultramafic rocks lack aluminium, which allows carbonate to react with magnesium silicates to form talc.46. It is found in ultramafic ridges. 47. It comprises pillow basalts, dolerites, gabbros, ultramafic rocks, cherts and massive sulfides. 48. It occurs as replacements of copper and nickel phases in serpentinites and other altered ultramafic rocks. 49. Pargasite is a rare magnesium-rich amphibole with essential sodium, usually found in ultramafic rocks. 50. Low silicon content is indicative of mafic and ultramafic igneous rocks, such as basalt and dunite.
