Mount Desire Dyke

Mount Desire Dyke is designated place of geological significance. It is located 16 km (9.9 mi) north-east of Hawker in South Australia, on the edge of the Flinders Ranges. The dyke (or dike) is a rock structure where mobile material, being a breccia of rock salt and rubble (as in 'salt diapirs') has intruded into cracks in folded Adelaidean sediments in the geological past [1][2]

The site was added to the South Australian Heritage Register on 30 March 1998. Its significance is described as follows:[1][3]

This site contains a number of features of considerable importance to research and debate concerning the nature and origin of the Mt Desire Dyke and other diapirs of the Flinders Ranges, including: typical dolomitic-vanished evaporite breccia and dolostone/metasediment xenoclasts (to km in size) of probable Willouran origin; sharp irregular and distinctive contacts with early Cambrian units such as the Mernmerna Formation, Oraparinna Shale, and Wilkawillina Limestones, including a particularly important apophysis interpreted as an intrusive re-entrant; and significant brecciation in, and metamorphic incongruence between, the material of the dyke and the adjacent Cambrian limestones.