Pattern of apparent total strain in the bedded anhydrite cap of a folded salt wall

• Published in: Canadian Journal of Earth Sciences
• Main Authors: Schwerdtner, W. M., Torrance, J. G., Berkel, J. T. van
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1989
• Subjects: General Earth and Planetary Sciences; Arctic; Eureka; Heiberg; Axel Heiberg Island; Eureka Sound; muskox
• Online Access: http://dx.doi.org/10.1139/e89-079; http://www.nrcresearchpress.com/doi/pdf/10.1139/e89-079

The dense anhydrite cap of the southern Muskox Ridge salt wall participated in the large-scale buckling of Mesozoic clastic strata at the western boundary of the Tertiary Eureka Sound fold belt on Axel Heiberg Island, Canadian Arctic. This Carboniferous anhydrite is an aggregate of strained diagenetic nodules and contains relict limestone beds that mark the paleohorizontal plane. The well-exposed cap provides an excellent example of fold decollement and redeformation of foliated rocks.The horizontal pattern of the nodule-shape fabric was delineated within folded and straight segments of the cap. Maps for a well-exposed folded segment show systematic variations in the intensity of apparent total strain (r) and the prolateness factor (k). If the nodule fabric pattern of adjacent straight walls represents the prefold structural state of all walls in the area, then the pattern of folding strain can be reconstructed in the southern Muskox Ridge cap. Here, the preflattened anhydrite was deformed by flexural shear in most localities, but was shortened passively near its contact with competent clastic rock.