Pillow shelves form in the upper parts of pillows or lava tubes, and record pauses in their drainage. Thus the recognition of pillow shelves in tectonically deformed pillows allows both the palaeohorizontal (i.e., bedding) direction and approximate way-up direction to be determined. This is demonstrated in an example from the Cape Smith Fold Belt of northern Quebec, where way up and bedding were independently determined. The establishment of way up in strongly deformed pillow sequences enables structural facing direction to be determined and is a crucial step in the elucidation of the structural history in terrains where pillowed basic volcanics predominate, e.g., greenstone belts.

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