Fragments of the mantle and crust from beneath the Sierra Nevada batholith: Xenoliths in a volcanic pipe near Big Creek, California

Physics and Chemistry of Deep Continental Crust Recycling

“…The Cretaceous Sierra Nevada batholith was once underlain by a thick layer of mafic cumulates in the form of garnet-pyroxenites making up the lower crust and parts of the lithospheric mantle (Figures 2(a) and 3; Dodge et al, 1988;Ducea, 2001Ducea, , 2002Saleeby, 1996, 1998b;Lee et al, 2006Lee et al, , 2007Mukhopadhyay and Manton, 1994). These cumulates have been shown to be petrogenetically linked to the granodioritic plutons dominating the batholith (Ducea, 2002;Ducea and Saleeby, 1998b;Lee et al, 2006Lee et al, , 2007.…”

Origin of High Mountains in the Continents: The Southern Sierra Nevada

“…Pressure-temperature SCIENCE VOL. 271 data for CS garnet peridotites and garnet websterites (19) yield an adiabatic slope (Trend B, Fig. 5), suggesting that the convective upper mantle was as shallow as -60 km.…”

“…Xenoliths from Late Cenozoic volcanic flows from the central Sierra (CS suite), the High Sierra, Owens Valley, and Inyo Mountains (HS suite) show variations in texture, composition, and thermal history consistent with the MT and seismic anomalies. The CS suite includes feldspathic granulites, garnet-pyroxenites, eclogites, cumulate gabbros and amphibolites, garnet and spinel peridotites, and garnet websterites (18)(19)(20). The HS suite includes spinel lhetzolites, hatzburgites, spinel dunites, spinel webterites, clinopyroxenites, gabbros, and mafic granulites, but lacks garnet.…”

“…Equilibration pressure-temperature determinations on Sierra Nevada xenoliths(19,21).Trends A, B, and C are explained in the text. Symbols: 0, feldspathic granulites; 0, garnet clinopyroxene rocks; A, garnet peridotites and garnet websterites; +, spinel peridotites from the CS; B, spinel peridotitesfrom the HS.…”

Foundering Lithosphere Imaged Beneath the Southern Sierra Nevada, California, USA

“…There are three groups of xenoliths: garnet pyroxenites and garnet peridotites (both erupted before 8 Ma) constituting the old mantle lithosphere (2,20) and fertile, olivine-rich, garnet-free spinel peridotites (erupted since 4 Ma) with an asthenospheric affinity (2). Chemically, the garnet and pyroxene in the pyroxenites tend to have low Mg, whereas the olivine in the peridotites has a higher Mg number (2).…”