Question

In the earlier twentieth century, many geologists and meteorologists contributed ideas to the theory of tectonic plates. What evidence did they cite to show that the plates in Earth's crust were not fixed?

a. Fossil evidence of marine life in landlocked regions
b. The discovery of subduction zones and mid-ocean ridges
c. Evidence of consistent climate patterns across continents
d. The presence of sedimentary rocks in mountain ranges

Answer 1

Evidence for the theory of plate tectonics includes fossils of marine life found in now dry areas, discoveries of subduction zones and mid-ocean ridges, and the presence of sedimentary rocks in mountain ranges. These observations helped to build the case for the once controversial idea of continental drift, leading to the widely accepted theory of plate tectonics.

Step-by-step explanation:

The evidence cited to show that the plates in Earth's crust were not fixed comes from several observations made in the early twentieth century. Major evidence included fossils of marine life found in landlocked regions far from any oceans which suggests these areas were once covered by water. Another significant observation was the discovery of subduction zones and mid-ocean ridges, indicating that new crust was being created and old crust was being recycled into the Earth's mantle.

The presence of sedimentary rocks within mountain ranges was also indicative of the forces of plate tectonics as sedimentary layers typically form in marine environments. Wegener's early work on continental drift also provided foundational evidence for moving plates, with his hypotheses being crucial to the development of the modern theory of plate tectonics.