Final answer:
The primary indications of active plate tectonics on a newly discovered Earth-like planet would be the presence of geological features such as active volcanoes, mountain ranges, occurrences of earthquakes, and the presence of fossils or trace elements in sedimentary rocks. However, these indications alone cannot be definitive proof of active plate tectonics, requiring other geophysical data for confirmation.
Step-by-step explanation:
The best indication that a newly discovered Earth-like planet may have plate tectonics would be the presence of active volcanoes and extensive mountain ranges which are a result of geological activity caused by tectonic movements. Plate tectonics, the movement of large sections of a planet's crust due to mantle convection, results in geomorphological features such as mountains, valleys, and volcanoes on the planet's surface. For instance, Earth's geology is predominantly driven by plate tectonics, resulting in features such as the Hawaiian island chain, rift zones, and faults.
Another critical indication would be the occurrence of earthquakes, an indication of crustal movement and transformation. Also, fossils or trace elements in sedimentary rocks could suggest plate movements created conditions for life. This context adds to the idea that plate tectonics is a significant element in assessing a planet's geologic and, potentially, biological history.
However, the mere presence of such features is not conclusive proof of active tectonics and additional evidence would be needed to assert the presence of plate tectonics. Such observations would be handled with other geophysical data to gain a deeper understanding of the planet's geotectonic characteristics.
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