Timing and mechanisms of subduction and exhumation in the Hellenides: Structural and geochronological constraints from Andros and South Evia
The Greek mountains were formed in several phases
The Greek mountains were not formed during a single, prolonged geological process, but through several phases in which rock was pushed deep into the Earth and later rose back to the surface. This is evident from the doctoral research conducted by geoscientist Shijie Shang on rocks on the Greek island of Andros and in southern Evia. The results shed light on how the movement of tectonic plates over millions of years has shaped the current landscape.
Shang studied what are known as subduction and exhumation. During subduction, rock is carried deep into the Earth by the movement of tectonic plates, while during exhumation, it is subsequently brought back toward the Earth’s surface. By combining field observations with the dating of individual mineral grains, Shang was able to distinguish between different phases in this complex history.
One of the most important discoveries is a previously undescribed fault system on Andros: the Andros Detachment. This fault system played a role in bringing deeply buried rocks to the surface. In southern Euboea, Shang also identified a new geological unit and was able to revise the relationships between different rock sequences.
Shang’s research also shows that mountain-building processes did not occur simultaneously throughout the region. The times when rocks were deeply buried varied from north to south. This provides a more accurate picture of the development of the Hellenides, the mountain system associated with the convergence of the African and Eurasian plates.
Rocks as the Earth’s Archive
The results are not only important for the geological history of Greece. Rocks can contain traces of multiple events that occurred millions of years apart. When an entire rock sample is dated as a single unit, it can be difficult to distinguish between these different events. By dating individual mineral grains, researchers can better distinguish between different phases and construct a more reliable geological timeline.
This knowledge helps scientists better understand how the Earth’s crust and mountain ranges evolve over long periods of time. Furthermore, the approach used in this research can be applied to other regions with complex geological histories. In this way, the research contributes to a more accurate understanding of the processes that shape the Earth’s crust—and ultimately, the landscapes around us.
More information about the dissertation.