Cambrian-Ordovician slope conglomerates in the Humber Zone, Quebec reentrant, Quebec

Cambrian-Ordovician deep-water sediments in the Humber Zone of the Quebec Reentrant occur in thrust complexes in eastern Quebec. The lithostratigraphy is complex because of the use of locally defined units. Limestone conglomerates are used to refine this framework. Lower Cambrian conglomerates consist of oligomict and polymict varieties with slope- and platform-derived clasts in a quartzose matrix. Upper Cambrian polymict conglomerates differ in their composition and characteristics, conglomerates form decametre-thick fining-upward units. Clasts include shallow water limestones and siliciclastics, slope-derived siliciclastic rafts, and abundant basement fragments. Ordovician conglomerates are finer grained (except in the southern area) and occur in thin successions. They consist of platformal and slope material with lime mudstone as the dominant clast type.