Upper Paleozoic Rocks
The Silurian to mid Devonian Acadian Orogeny resulted in an extensive region of uplands across Atlantic Canada. Isolated occurrences of Lower to Middle Devonian redbed conglomerates, arkosic sandstones and mudstones, locally with intercalated felsic and/or mafic volcanic flows, are the earliest post-orogenic deposits. These became gradually thicker and more widespread so that by Middle Carboniferous time, large tracts of the orogen were buried by sedi-mentary rocks including coarse to fine red and grey terrigenous clastics, oil shales, coal, carbonates, and evaporites. Variation in sediment accumulation rates, syndepositional uplift, and extensive reworking of earlier deposits have greatly complicated the upper Paleozoic litho-stratigraphy. This situation has been complicated further by widespread subsequent faulting, tilting, folding, and erosion.
Tilted and/or downfaulted regions in which upper Paleozoic rocks accumulated and/or have been preserved are referred to as "basins" (Fig. 5.1). The name "Maritimes Carboniferous Basin" (Roliff, 1962) or "Maritimes Basin" (Williams, 1974) has in practice become a collective term for the total area in eastern Canada that is presently underlain by upper Paleozoic rocks contained in structural basins, including the offshore. In this sense the "Maritimes Basin" is essentially a basin complex comprising structural remnants of a formerly more extensive area of upper Paleozoic rocks. The designation "Maritimes Basin" is useful however in that it serves to distinguish the area of Upper Paleozoic rocks in Atlantic Canada from the Appalachian, Illinois, and other basins in the United States.
The upper Paleozoic rocks contained in the Maritimes Basin complex constitute an approximately east-westtrending region with
Figures & Tables
This volume focuses on the highly populated Canadian Appalachian region. The chapter on the East Greenland Caledonides stands alone and there is no attempt to integrate the geological accounts of the two far removed regions. Rocks of the Canadian Appalachian region are described under four broad temporal divisions: lower Paleozoic and older, middle Paleozoic, upper Paleozoic, and Mesozoic. The rocks of these temporal divisions define geographic zones, belts, basins, and graben, respectively. The area is of special interest because so many modern concepts of mountain building are based on Appalachian rocks and structures.