Samples from three petrographically distinct, intrusive kimberlite bodies and associated kimberlite dykes from the eastern lobe of the Du Toitspan kimberlite pipe, Kimberley, South Africa, have been analysed for their bulk rock major and trace element compositions and their olivine and phlogopite compositions. The two dominant intrusive bodies (D13, D14) are distinguished by the one (D13) being phlogopite-rich and best classified as a macrocrystic hypabyssal phlogopite kimberlite, and the other (D14) being phlogopite-poor and best classified as a macrocrystic hypabyssal monticellite kimberlite. The minor D17 intrusive body is classified as a macrocrystic transitional hypabyssal serpentinized phlogopite kimberlite. The associated kimberlite dykes range texturally from aphanitic to macrocrystic and are classified as calcite kimberlites.

The major kimberlite intrusions and their associated dykes show no evidence of crustal contamination and are characterised by broadly overlapping geochemistry except for distinctly higher K₂O (> 2 wt%) and Al₂O₃ (>3 wt%) and flattening HREE patterns (Gd/Yb_N = 6.5–7.0) in the D13 – phlogopite kimberlite compared to the D14 – monticellite kimberlite and the calcite kimberlite dykes (Gd/Yb_N = 9.6–12.1). These distinguishing geochemical features of the D13 – phlogopite kimberlite are comparable to typical Group II kimberlites in southern Africa. However, their diagnostic incompatible trace element ratios (for example, Th/Nb, La/Nb, Ce/Pb, and Ba/Nb) are instead comparable to other kimberlite intrusions analysed in this study and to southern African Group I kimberlites in general.

Semi-quantitative modelling suggests that these kimberlite intrusions could have derived by low (<1%) degrees of partial melting of a source region that is enriched in LREE (La_n = ~6.1; Yb_n ~ 1.47) comparable to metasomatised peridotites from the underlying lithospheric mantle. The composition of the D13 phlogopite kimberlite is consistent with a partial melt of a modally metasomatised source containing a higher proportion of residual clinopyroxene relative to garnet (compared to that giving rise to the D14 monticellite kimberlite and calcite kimberlite dykes), as well as accessory amounts of phlogopite, i.e. a garnet phlogopite peridotite (GPP). The absence of K-anomalies on primitive mantle normalized diagrams for the D13 phlogopite kimberlite requires that phlogopite was not a residual phase during partial melting and was exhausted shortly before or at the moment of melt segregation. The higher Gd/Yb ratios and lower K₂O in the D14 monticellite kimberlite and calcite kimberlite dykes can be explained by partial melting of a cryptically metasomatized, phlogopite – free, garnet peridotite (GP) source, containing a higher proportion of garnet relative to clinopyroxene. The low absolute K and strong negative K-anomaly on primitive mantle normalized diagrams for the D14 monticellite kimberlite were inherited from a source region that previously experienced cryptic metasomatism by a differentiated fluid already carrying a negative K-anomaly.

分析了来自南非金伯利Du Toitspan金伯利岩管东瓣的三个岩石学上截然不同的侵入性金伯利岩体和相关的金伯利岩堤，分析了它们的主要岩石和微量元素组成以及橄榄石和金云母组成。两个主要侵入体（D13，D14）的特征在于，一个（D13）富含金云母，最好归类为大晶状的斜方金云母金伯利岩，另一个（D14）是贫金云母，并且归类为一个大晶状的斜方玄武岩金伯利岩。较小的D17侵入体被分类为大晶过渡性蛇行蛇纹石化金云母金伯利岩。关联的金伯利岩堤在质地上从泛晶型到大晶状，并被分类为方解石金伯利岩。

主要的金伯利岩岩侵入体及其相关的堤坝没有证据表明存在地壳污染，其特征是地球化学广泛重叠，除了明显更高的K ₂ O（> 2 wt％）和Al ₂ O ₃（> 3 wt％）以及平坦的HREE模式（ GD /镱_ñ = 6.5-7.0）在D13 -金云母金伯利岩相比，D14 -钙镁橄榄石金伯利岩和方解石金伯利岩堤坝（GD /镱_ñ= 9.6–12.1）。D13 –金云母金伯利岩的这些独特的地球化学特征与南部非洲典型的II类金伯利岩相当。但是，它们的诊断性痕量元素比率不兼容（例如，Th / Nb，La / Nb，Ce / Pb和Ba / Nb）与本研究中分析的其他金伯利岩侵入岩和一般的南部非洲I类金伯利岩相当。

半定量建模表明，这些金伯利岩岩体侵入可能是由富含LREE的源区的部分融化程度低（<1％）引起的（La _n =〜6.1; Yb _n〜1.47）与下层岩石圈地幔的交代橄榄岩相媲美。D13金云母金伯利岩的成分与部分交代的源的部分熔融相一致，相对于石榴石，其含有更高比例的残留次氯环己烯（相比之下，产生D14蒙脱石金伯利岩和方解石金伯利岩堤）以及辅助量金云母，即石榴石金云母橄榄岩（GPP）。D13金云母金伯利岩的原始地幔归一化图上没有K异常，要求金云母在部分熔融过程中不是残留相，并在熔体偏析之前或之时被耗尽。较高的Gd / Yb比和较低的K ₂D14蒙脱石金伯利岩和方解石金伯利岩堤中的O可以通过隐密交代的，不含金云母的石榴石橄榄石（GP）来源的部分熔化来解释，相对于斜cl石，石榴石中的石榴石比例更高。D14蒙脱石金伯利岩原始地幔归一化图上的绝对K值低且负K异常强，是从源区域继承而来的，该源区域以前曾因已经携带负K异常的微分流体经历了隐性交代作用。