Final answer:
The major oil-producing landform in the Great Plains is the Ogallala Aquifer area, known for its underground oil and gas deposits. Arctic Alaska also contributes significantly to U.S. oil production through the National Petroleum Reserve.
Step-by-step explanation:
The major landform that is an important oil-producing area in the Great Plains region is the Ogallala Aquifer. This immense underground water reservoir, which spans across parts of Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, Texas, and Wyoming, not only supports large-scale irrigation for agriculture but also lies beneath regions known for their natural resources, including oil and gas deposits.
The extraction of these resources, especially oil, informs significant economic activity in the Great Plains. Moreover, Arctic Alaska, with its enormous National Petroleum Reserve, has historically been a vital source of oil for the United States.
Oil exploration and production in the Great Plains are intimately tied to geological studies, such as seismic surveys by the U.S. Geological Survey, which help reveal the location and composition of oil-bearing formations. Expansion of oil production in the Great Plains aligns with broader trends of intensive resource extraction and industrial agriculture in the region, which have reshaped the landscape and economy over the past century.