21. There are bands of ultramafic rock near the Missisquoi River valley, and basalt also occurs. 22. Ultramafic rocks also contain elevated amounts of chromium and nickel which may be toxic to plants.23. Thus, ultramafic rocks have high Sm and low Nd and therefore " high" 24. Ultramafic rocks lack aluminium, which allows carbonate to react with magnesium silicates to form talc.25. It comprises pillow basalts, dolerites, gabbros, ultramafic rocks , cherts and massive sulfides. 26. It occurs as replacements of copper and nickel phases in serpentinites and other altered ultramafic rocks . 27. Pargasite is a rare magnesium-rich amphibole with essential sodium, usually found in ultramafic rocks . 28. "Nepenthes danseri " most commonly inhabits open scrub or bare soils on ultramafic rock . 29. His primary field of expertise is the formation and plate tectonic setting of ophiolites and ultramafic rocks . 30. Several igneous associations are noted : high-alumina basalts, ultrapotassic igneous rocks, and ultramafic rocks .
