during the 1960s scientist were already equipped with gadgets needed to explore the deep ocean. what discovery about the ocean floor is associated with the seafloor spreading?

The key discovery was that the ocean floor is youngest at the mid-ocean ridges and becomes older as you move away from them on both sides. This age pattern, together with matching “magnetic stripes” (bands of rock recording past reversals of Earth’s magnetic field in symmetrical patterns on either side of mid-ocean ridges), showed that new crust is created at mid-ocean ridges and the seafloor spreads outward from there.