Ann: Large gold system defined at Crow, page-83

amertoo as far as the 30yr research literature on the Mallina Basin is concerned ,there’s no record or evidence for volcanic pipes that I know of here.As well DEG record them as intrusions.
Other reasons I don’t think so is the high Mg content ( and other elements) of these intrusions ,this is a flag that these intrusions have mantle origins- volcanic pipes are too shallow.
If it’s lamprophyres yr referring to , yes they have the same deep origins as these intrusions but they’re too small for the volume of mass material here.And there’s no recorded swarms of lamprophyres here as well to make up this volume.Though they are found with the Black Flag Group ( BFG) of intrusions in the Yilgarn. I know E.E at DGO was interested in the BFG.
Another reason is that lamprophyres are primarily mafic and these intrusions have a intermediate mafic- felsic composition.