👉 The Arizona Fluid, also known as the San Pedro River Fluvial System, is a vast and complex network of ancient river channels, floodplains, and associated sedimentary deposits that once flowed through the southwestern United States, particularly in present-day Arizona. This system is a testament to the region's geological history, dating back millions of years during the Pleistocene epoch. It was formed by intermittent rivers that carved through the landscape, depositing layers of sand, silt, and clay as they shifted course. Today, the Arizona Fluid is a critical habitat for diverse flora and fauna, including several endangered species, and plays a significant role in the ecological balance of the Sonoran Desert. Its study provides valuable insights into past climatic conditions and helps scientists understand the region's hydrological dynamics and potential future changes.