Upper Triassic Tethyan-type reefs in the Yukon.

An Upper Triassic reef complex is well exposed at Lime Peak, in the S Yukon. It consists of superimposed patch reefs and bedded inter-reef limestone and is surrounded by volcaniclastic rocks. The reefs are up to 150m thick, and are the first Tethyan-type sponge reefs recognized in North America. The inter-reef limestones include thick-bedded accumulations of locally derived organisms, and thin-bedded deposits of reef-derived debris. The Lime Peak fossils are a mixture of those with Tethyan affinities, North American endemics, and new forms, possibly reflecting the origin of Stikinia between the Tethys and cratonic North America.-from Authors