A recent study led by Sean Regan from the University of Alaska Fairbanks has revealed that three sites along the Denali Fault in Alaska were once part of a unified geological structure, marking the integration of Wrangellia into North America. The research, published in Geology, identifies these sites as forming a terminal suture zone due to tectonic activities that tore them apart over millions of years. The work elucidates the process of lithospheric growth along North America’s western margin, suggesting that prior theories which posited these sites formed independently may have been inaccurate.
Regan’s research utilized the concept of inverted metamorphism, where hotter, high-pressure rocks overlie cooler, lower-pressure ones, to trace geological history. This phenomenon indicates the complexity of tectonic interactions and aids in understanding crustal deformation. By analyzing monazite, a rare earth mineral from the three locations, Regan demonstrated that they shared similar ages and structural settings. The findings emphasize the importance of linking distant geological formations to reconstruct the tectonic evolution of the region, shedding light on the ancient processes that shaped North America’s landscape between 72 and 56 million years ago.
