But the bulk of the moraine is composed of porphyritic granite derived from Feldspar and Cathedral Valleys.
但大部分冰碛是由长石谷和大教堂谷中的斑状花岗岩组成的。
英语百科
Granite
Granite (pronunciation: /ˈɡrænᵻt/) is a common type of felsic intrusive igneous rock that is granular and phaneritic in texture. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy. The word "granite" comes from the Latin granum, a grain, in reference to the coarse-grained structure of such a holocrystalline rock. By definition, granite is an igneous rock with at least 20% quartz and up to 65% alkali feldspar by volume.