Abstract

W. R. Church writes: In discussing the implications of their new 590 Ma minimum age for the Scottish Dalradian succession, Rogers et al. 1989 correctly point out that, if the Fleur de Lys Supergroup of NE Newfoundland represents a basinal facies to the Cambro-Ordovician shelf succession of Western Newfoundland, then the long held equivalence of the Dalradian and the Fleur de Lys must be reconsidered. The stratigraphy of the latter and the consequent implications in this regard are however more complicated than might be generally thought.

The Fleur de Lys Supergroup is composed of three, if not more, structural/stratigraphical units, whose tectonic relationships are as speculative as those of the Moine and Dalradian series. The unit which has been held, on the basis of a single brachiopod fragment (S. Stouge, pers. comm. to Hibbard 1983, p. 31), to be the equivalent of the Western Newfoundland Cambro-Ordovician shelf succession is represented by a narrow synformal group of carbonates, epidotitic amphibolite, and pelite/psammite (White Bay Group), located along the western margin of the Fleur de Lys. In contrast, the eastern margin of Fleur de Lys is composed of an imbricate zone of psammitic and mafic schists of quite a different character. The upper part of this sequence, the Birchy Schist Complex, is composed of a highly strained and dismembered ophiolite/ophiolite- melange assemblage. Clearly discernible sheeted dolerite is exposed north of Slaughter House Cove (dyke analysis: SiO, 48.67, FeO/MgO 1.68, TiO, 2.32, Zr 97, Y 40). The lower part, the Rattling Brook Group,

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