Section at Five Islands Provincial Park

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Spectacular outcrops at Five Islands Provincial Park reveal much of the Fundy basin section in the Minas subbasin. Here, in a wide angle photograph we are looking north from the rock promontory known as the "Old Wife". On the left is the McCoy Brook Formation. It is faulted down against North Mountain Basalt along a normal fault zone. Meso-scale structures within the fault zone show clear evidence of late reverse movement of considerable magnitude (Withjack et al., 1995).

The North Mountain basalt itself (center) is strongly deformed with basalt columns showing progressive (if locally chaotic) counterclockwise rotation about a horizontal axis. Much of the basalt has be crushed to a tectonic breccia.

On the right is the Blomidon Formation and overlying North Mountain Basalt separated from the basalt in the center of the image by a high angle fault or uncertain attitude. The "Red Head beds" lie to the far right, out of view. The Triassic-Jurassic boundary (below) lies within the prominent white layer at the top of the Blomidon Formation.


Here is the uppermost Blomidon Formation, containing the Triassic-Jurassic boundary, viewed looking west from the cliff seen in the first image. Joseph Smoot (foreground - USGS) is shown here cutting steps for Mark Anders (LDEO) along the steep mudstone face. Although these outcrops are slightly baked due to the overlying basalt, nearby outcrops have produced a diverse assemblage of pollen and spores documenting the Triassic-Jurassic boundary (Fowell and Traverse, 1995).


The most eastward and stratigraphically lowest outcrops of the Blomidon Formation at Five Islands are internally deformed by evaporite solution collapse structures and these possibly related synsedimentary domino-style faulting (Ackermann et al., 1995).


Ackermann, R. V., Schlische, R. W., and Olsen, P. E., 1995, Synsedimentary collapse of portions of the lower Blomidon Formation (Late Triassic), Fundy rift basin, Nova Scotia. Canadian Journal of Earth Science, v. 32, p. 1965-1976.

Fowell, S. J. and Traverse, A., 1995, Palynology and age of the upper Blomidon Formation, Fundy Basin, Nova Scotia. Review of Palaeobotany and Palynology. v. 86, p. 211-233.

Withjack, O. M., Olsen, P. E., and Schlische, R. W., 1995, Tectonic evolution of the Fundy rift basin, Canada: Evidence of extension and shortening during passive margin development. Tectonics, v. 14, no. 2, p. 390-405.