A wealth of detailed data exists for the Canadian Appalachian region. Presentation of data for an orogen as complex as the Appalachian can be problematical. In this chapter the presentation of these data is based on temporal and spatial divisions of rock units. Previous analyses of the Canadian Appalachian region reflected theories in vogue at the time of their undertaking. Thus prior to the wide acceptance of plate tectonics and continental drift, analyses reflected geosynclinal theory. These varied in detail, from the early work of Schuchert (1923) to the sophisticated compound geosynclines that served as a theme for the fifth edition of the Geology and Economic Minerals of Canada (Poole et al., 1970). Subsequent to plate tectonics, conceptual plate models have abounded. Many were contrived on local relations and abandoned as new information on the geology was uncovered.
Analyses based on “as is” tectonostratigraphic spatial divisions are those that have met with most success. Thus divisions in the U.S. Appalachians (King, 1950, 1959) such as Appalachian Foreland, Valley and Ridge, Blue Ridge and Piedmont provinces, are still in wide usage. Similarly, the tripartite division of Newfoundland (Williams, 1964, see Fig. 1.16), Western Platform, Central Volcanic Belt and Avalon Platform (Kay and Colbert, 1965) remains little changed, though introduced well before the plate tectonic revolution. These are meaningful geographic divisions used in objective syntheses that describe rocks and structures, while attempting to separate what is known, from what is interpreted.
In any objective “as is” account, decisions must be made at
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.