Final answer:
The theory of plate tectonics was supported by new evidence such as sea-floor spreading, earthquake studies, and the age and magnetic patterns of ocean floor rocks, which helped uncover the mechanism for continental drift.
Step-by-step explanation:
New Evidence Leading to the Theory of Plate Tectonics
The theory of plate tectonics was developed from the hypothesis of continental drift, proposed by Alfred Wegener in the early 20th century. Although Wegener provided substantial evidence—such as the jigsaw fit of continents, matching fossils, corresponding mountain ranges, and paleoclimatic indicators—his hypothesis lacked a mechanism for how continents could move. It wasn't until the 1960s, with advances in geology, oceanography, and geophysics, that new evidence emerged. Key developments included the discovery of sea-floor spreading, studies of earthquakes, and the mapping of the ocean floor which showed mid-ocean ridges and corresponding trenches.
One of the most compelling pieces of evidence was the observation of young, geologically active mid-ocean ridges, contrasted with the older, sediment-covered ocean floor farther from these ridges, supporting the theory that the ocean floor was moving and renewing itself. Magnetic striping patterns of the ocean floor, aligned with Earth's magnetic poles, provided additional evidence, these patterns showed that the sea floor was spreading from mid-ocean ridges, pushing continents apart. Thus, the plate tectonics theory provides a unifying context for understanding geological phenomena, from the distribution of fossil records to the mechanism behind earthquakes and volcanic activity.