PROGNOSTICATION OF PRIMARY DIAMOND DEPOSITS

Prognostication of primary diamond deposits (kimberlites and lamproite s), located within diamondiferous provinces on ancient cratons, is bas ed on using geological, geophysical and morphostructural models for ki mberlite/lamproite zones, fields and clusters. The zones that control kimberlite/lamproite emplacement are characterised by widespread devel opment of intrusive and volcanic rocks and block structure. They are r eflected in geophysical data by sharply contrasting, elongated magneti c and gravity anomalies. The zones are divided into transcurrent intra cratonic, rift-related and zones of anomalous mantle. Within these bro ader zones kimberlite/lamproite fields are characterised by dome/block -shaped uplifts in geological structures; by sub-circular seismic, gra vity and magnetic anomalies, and by concentric-radial morphological st ructures. They may be recognised by the integrated analysis of geologi cal, geophysical and topographical maps, as well as aerial and satelli te images. Several new kimberlite fields have been found using these t echniques.