The Making of a Future Accreted Terrane: Development of the Queen Charlotte Terrace Adjacent to Haida Gwaii, Canada

The Queen Charlotte Terrace is a distinctive morphologic feature adjacent to the Haida Gwaii archipelago along the Pacific margin of Canada. Its formation and subsequent evolution are directly linked to changes over the past ∼15 My in relative plate interactions (Pacific and North America), the routing of sediments shed from North America, and deformational processes within a transpressional corridor along Haida Gwaii. A detailed study of the surficial and internal structure of the Queen Charlotte Terrace in concert with geophysical imaging and modeling of the plate boundary structure and interactions allows us to define the formation and development of this nascent terrane. Its development in association with the Queen Charlotte transform fault provides the mechanism to transport this new terrane substantial distances before it ultimately becomes accreted to North America. With its ultimate accretion to North America (perhaps outboard of the presently accreting Yakutat terrane), it will likely be a supracrustal unit similar to other of the accreted suspect terranes along the western margin of North America.