氷河

1. Origins, structure, and basic meaning

• Structure: 氷河 (ひょうが) is a massive body of ice moving over long periods. 氷河を眺める makes it an object of observation; 氷河が削った跡 makes it the agent of erosion.
• Basic usage: A glacier flowing through a valley is viewed from a lookout, while rock retains traces carved by a past glacier.

2. Common pitfalls and similar expressions

• Glacier observed and glacier shaping terrain
  • を marks the natural object currently viewed; が marks the source of past erosion. In the second sentence the head noun of the larger phrase is 跡, not the headword.