PRELIMINARY DISCUSSION ON METALLOGENIC SERIES OF PRIMARY DIAMOND DEPOSITS

Up to now, the known diamond bearing rocks, pro alkaline and ultra mafic, include kimberlite, lamproite, eclogite, ophiolite suite, alkaline ultrabasic complex, alkaline ultrabasic lamprophyre, peridotite series (including harzburgite and dunite). However, the primary diamond deposits worthy of exploration in terms of economic value occur only in the kimberlite and lamproite. In addition, only a small amount of micro grain diamond occurs in other types of rocks. Although both kimberlite and lamproite originated from the deep mantle, relatively conspicuous differences arise in chemical compositions, rock forming minerals, tectonic settings, and isotope data, resulting in two metallogenic series of primary diamond deposits: kimberlite type and lamproite type primary diamond metallogenic series. The kimberlite type primary diamond metallogenic series is divided into three sub series of mineralization in terms of chemical compositions: rich Cr, Ti and Mg kimberlite type diamond metallogenic sub series, poor Cr, Ti and Mg kimberlite type diamond metallogenic sub series, and the kimberlite sub series with complex chemical compositions (of transitional type) between the first two sub series. However, the lamproite type primary diamond metallogenic series is classified in terms of major mineral components as olivine lamproite primary diamond metallogenic sub series, leucite lamproite primary diamond metallogenic sub series and the transitional subseries lying between the first two subseries. In the meantime, both the kimberlite type metallogenic series and the lamproite metallogenic series can be classified as three metallogenic subseries (from early to late) respectively in terms of their corresponding field geological occurrences: kimberlite/lamproite type volcanic sedimentary tuff primary diamond metallogenic sub series, kimberlite/lamproite type volcanic tuff and breccia primary diamond metallogenic sub series, and kimberlite/lamproite type volcanic subvolcanic intrusion facies primary diamond metallogenic sub series.