Diamondiferous xenoliths from crustal subduction: garnet oxygen isotopes from the Nyurbinskaya pipe, Yakutia

Subduction-related origin of eclogite xenoliths from the Wajrakarur kimberlite field, Eastern Dharwar craton, Southern India: Constraints from petrology and geochemistry

“…d 18 O values higher than 5.5& as the range observed here are typical for zeolite facies seafloor alteration and many cratonic eclogite xenoliths from kimberlites share this signature (e.g. Jacob, 2004;Spetsius et al, 2008;Pernet-Fisher et al, 2014).…”

“…This is a characteristic feature they share with many other cratonic eclogite xenolith populations, which exhibit d 18 O values significantly outside the mantle range (e.g. Eiler, 2001;Jacob, 2004;Spetsius et al, 2008;Pernet-Fisher et al, 2014). This is generally taken to indicate seawater alteration of their oceanic crustal protoliths prior to subduction and is based on a broad analogy with ophiolites (Gregory and Taylor, 1981) as well as drilled profiles through modern oceanic crust (Bach et al, 2001).…”

Monomineral universal clinopyroxene and garnet barometers for peridotitic, eclogitic and basaltic systems

“…General division of mantle eclogites to groups A (Mg-rich); B (common meta-basaltic) and C (high Fe-Na-Al) was completed by the addition of high Ca group (Spetsius et al, 2008;Viljoen et al, 2009). The geotherm for the Mir pipe ( Fig.…”

“…The basaltic groups show increasing P-Fe# from the SCLM base and descending from the top; they also reveal the inflection near this boundary. This boundary is also is the upper limit for the pressure determined for the peridotitic diamond inclusions (Spetsius et al, 2008) and diamond-bearing eclogites. The latter form several (4) (Fig.…”

“…The Burkal basalt locality in the Khantay range (Ashchepkov et al, 1996) In the East Sayan mountain range (Ivanov et al, 2008) mainly fertile peridotite xenoliths with relic garnet were studied. They have a lower heating degree and lie on a geotherm located slightly below 90 mW/m 2 .…”