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很久以来就认为安大略省的早元古代高干达(Gowganda)组是冰川沉积层。时代相同的类似沉积物出露在密执安州北半岛的弗恩溪和死河储水盆地北侧,怀俄明州的梅迪辛保山脉和魁北克北部的席布加莫等地区。这些冰川沉积物分布区彼此相距较远,由此表明,在早元古界时期曾发生过一次范围较广的冰川作用。上述多数区域的冰碛岩基质和纹层状泥质板岩的化学成分具有明显的相似性,故可能反映出苏必利尔克拉通的大部分地区的统一特性。
It has long been assumed that the Early Proterozoic Gowganda Formation in Ontario is a glacial sediment. Similar sediments of the same age were found in the areas of Fern Creek and the Dead-river water-storage basin on the northern peninsula of Michigan, the Medicisin Mountains in Wyoming, and the Chebomic region in northern Quebec. The distribution of these glacial deposits is far apart from each other, indicating that a wide range of glaciations have occurred during the Early Proterozoic. The chemical composition of the moraine matrix and laminar shale in most of these areas is clearly similar and therefore may reflect the uniformed nature of much of the Superior Belt and Craton.