An anthropologist looking to understand the impact humans have had on the environment by studying rock formations, polar ice caps and glaciers is most likely practicing what kind of anthropology?

The answer is "archaeology ".

Anthropology has four branches, which includes;

Archaeology, which relates to exploration of people groups and societies of the past. Biological Anthropology, which studies about practical experience in advancement, hereditary qualities, and wellbeing. Cultural Anthropology, which is about human social orders and components of social life. Linguistic Anthropology, which is about centralization of social human studies that spotlights on dialect in the public arena.

Archeological anthropology is the investigation of past people and societies through material remains. It includes the removal, examination and translation of antiques, soils, and social procedures.