Final Answer:
The sand that covers the Outer Coastal Plain comes from two primary sources: the Appalachian Mountains (Aₚₘ) and the Piedmont region (Pᵢₑᵥ).
Step-by-step explanation:
The Outer Coastal Plain, characterized by its sandy terrain, receives its sand primarily from the erosion and weathering of two distinct sources: the Appalachian Mountains and the Piedmont region. The Appalachian Mountains (Aₚₘ) contribute a significant portion of the sand through the breakdown of rocks and minerals over time. As rainwater and natural processes act on the Appalachian Mountains, the resulting sediments, including sand, are transported to the Outer Coastal Plain.
The Piedmont region (Pᵢₑᵥ), which lies between the Appalachian Mountains and the Atlantic Coastal Plain, is another key source of deposition. Erosion and weathering processes in the Piedmont contribute to the sediment load, including sand, that is transported to the Outer Coastal Plain. Over geological time, the transfer of these sediments from higher elevations to lower-lying areas occurs through various natural mechanisms, such as rivers and wind, shaping the landscape of the Outer Coastal Plain.
The combination of these two sources, the Appalachian Mountains and the Piedmont region, plays a pivotal role in supplying the sand that covers the Outer Coastal Plain. This geological process highlights the interconnectedness of different regions within a landscape, showcasing how the deposition of sediments contributes to the unique features and characteristics of the Outer Coastal Plain.