High Quality Content by WIKIPEDIA articles! The Yukon-Tanana Terrane (YTT) is a tectonic terrane that extends from central Alaska through central Yukon and into northern British Columbia, Canada and Southeast Alaska, USA. Extending over 2000 km, the YTT is the largest tectonostratigraphic terrane in the northern North American Cordillera. The Yukon-Tanana Upland is a physiographic province mostly underlain by rocks of the Yukon-Tanana terrane. The YTT consists of polymetamorphosed and polydeformed metasedimentary, metavolcanic, and metaplutonic rocks of Upper Paleozoic and older ages that were deposited or emplaced near the edge of the North American continental margin. Rocks in the terrane record a variety of tectonic settings and have experienced varying amounts of tectonic transport, both before and after amalgamation of the YTT with North America. Sequences of mainly parautochthonous quartz-rich sedimentary rocks derived from the North American continent also include meta-igneous rocks with mostly continental geochemical and isotopic signatures. Structurally higher sequences contain meta-igneous rocks with arc and back-arc characteristics. The Slide Mountain/Seventymile terrane, composed of volcanic rocks typical of seafloor and of typical seafloor sediments, is recognized as an ocean basin that divided parts of the YTT before amalgamation of the Yukon-Tanana Terrane with the continental margin.