Final answer:
The new sea floor process begins with a rapid seafloor drop creating deep-water sediment deposits, then progresses to mountain building, and finally returns to a stable passive margin with sediment deposition. Geological regression may expose some of this new seabed above water. Geologists study these processes through sediment coring and seismic imaging.
Step-by-step explanation:
The process of new sea floor formation involves several steps. Phase 1 is characterized by the rapid drop of the seafloor due to the massive weight of nearby mountain ranges. This load on the Earth's lithosphere causes it to bend and creates a concave basin, often filled with deep-water sediments like shales. As time progresses, organic materials like tiny sea plants and animals die and accumulate on the ocean floor, getting buried under layers of silt and sand, contributing to sediment buildup.
In Phase 3, following the uplift and mountain building, the area slowly transitions back to a stable passive margin. This area will experience fine sediment deposition and the development of shallow marine carbonates. Eventually, a process known as regression may occur, where areas of the previously submerged seafloor get exposed above sea level due to shifts in sea level or land elevation.
Geologists study this process by using methods akin to those described in Exercise 5.1, where sediment coring and the examination of stratigraphic columns provide insights into the historical layering and composition of ocean sediments. Seismic images, such as those from the IODP Expeditions for the Nankai Trough, further aid in the understanding of sediment accumulation and the structure of the ocean floor.