Mount Desire Dyke is designated place of geological significance. It is located 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 pastPhD thesis of Trev J Mount, 1975, on "Diapirs and diapirism in the Adelaide Geosyncline" (Flinders Ranges) now is published online (free download) by the Department of Energy & Mining (Geological Survey of South Australia) as Report Book 2021/00006
The site was added to the South Australian Heritage Register on 30 March 1998. Its significance is described as follows: 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.
See also Geology of South Australia
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