Our earlier studies continued in a diligent search for rare ultradeep xenoliths in the kimberlite diatreme at Jagersfontein. The search has met with moderate success insofar as 20 majorite-bearing (decomposed to *gt + lamellar px) xenoliths are identified. Discrete gts (1 to 2 cm), gt-rich layers (2 to 3 cm) in lherzolites, and rare megacrystic gts (>3 cm) from xenoliths characterize the ultradeep suite. Pyroxene lamellae are crystallographically controlled along {111} gt planes, but px may also be prismatic, lensoidal, coarsely graphic, or annular to gt; jigsaw, rather than 120° dihedral textures, are typical. Gt ranges from Pyr68-74 mole% and CaO - Cr2O3 relations, with two exceptions, are distinctly lherzolitic. Cpx = Wo37-46 mole%, Jd3-19 mole%, with 0.4 to 2.4 wt% Cr2O3; opx = 92 to 95 mole% en, and ol averages 92.5 mole% with maximum wt% 0.1 CaO, 0.4 NiO, and 0.1 Cr2O3. A new class of 10 ultradeep xenoliths has lamellar spinel (Cr/Cr + Al = 0.74; Mg/Mg + Fe = 0.58) in addition to cpx with gt >3wt% Cr2O3 (c.f. 0.5 to 1.5 for sp-free types). Five samples are texturally linked but are compositional outliers to the central body of data: two are sp hosts (Cr# 0.69, Mg# 0.76) and (Cr# 0.74, Mg# 0.57) to gt (Pyr72) + cpx (Jd14); one is a gt megacryst (Pyr80) with sp (Cr# 57, Mg# 69); and the remaining two are unusually rich in chromium with gt = 7.3 to 8.2 wt% Cr2O3, rimmed by cpx (2.3 to 3-3 wt% Cr2O3). In addition, there are 17 xenoliths with compositional affinities to the ultradeep suite but lacking the texturally diagnostic lamellar intergrowths of cpx in gt are possibly completely equilibrated to gt + irregular cpx. Results from the new collection substantiate our earlier conclusions that the mantle was sampled by thejagersfontein kimberlite from the lower lithosphere (250 to 350 km) and the transition zone (435 km) with diagnostic high P-T majorite in lherzolite that decomposed to gt + px at one or more interruptive stations (e.g. lithosphere-asthenosphere boundary), and at one or another time, en route to the surface. Homogeneous majorite occurs as diamond inclusions at Jagersfontein but these are eclogitic, leading to the proposition that the source region in the asthenosphere was an unassimilated mixture of lherzolite and eclogite in the Mid-Cretaceous at the time of kimberlite sampling. Important questions arise: Is majorite primordial; did majorite form exclusively from the transition of pyroxene; or did subsequent dissolution into coexisting garnet take place? Why has majorite not been identified in eclogite, nor diamonds of lherzolitic affinity? Does the formation of majorite and the crystallization of encapsulating diamond imply distinct high P-T events?

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