Sr-rich aragonite veins in Hyblean serpentinized peridotite xenoliths (Sicily, Italy): Evidence for abyssal-type carbonate metasomatism

Initial Results From the Oman Drilling Project Multi‐Borehole Observatory: Petrogenesis and Ongoing Alteration of Mantle Peridotite in the Weathering Horizon

“…Second, it has been proposed that formation of carbonate minerals via reaction of surface waters with peridotite can produce a significant carbon reservoir on this and other planets, and could potentially be emulated in accelerated systems for engineered carbon capture and storage (e.g., Kelemen & Matter, 2008). There have been numerous, related studies of carbon mineralization during natural weathering of peridotite in the Samail ophiolite (Chavagnac, Ceuleneer, et al., 2013; Chavagnac, Monnin, et al., 2013; Falk et al., 2016; Giampouras et al., 2020; Kelemen et al., 2011; Lacinska et al., 2014; Lacinska & Styles, 2013; Leleu et al., 2016; Mervine et al., 2014, 2015; Noël et al., 2018; Paukert Vankeuren et al., 2012, 2019; Rajendran et al., 2014; Rajendran & Nasir, 2019; Streit et al., 2012), elsewhere on Earth (e.g., Alt et al., 2012, 2013; Andrews et al., 2018; Arcilla et al., 2011; Beinlich et al., 2010; del Real et al., 2016; Gahlan et al., 2020; Manuella et al., 2019; Morrissey & Morrill, 2017; Oskierski, Bailey, et al., 2013; Oskierski et al., 2013a, 2013b; Picazo et al., 2020; Quesnel et al., 2013, 2016; Sánchez‐Murillo et al., 2014; Schwarzenbach et al., 2013, 2016; Ulrich et al., 2014), and on Mars (e.g., Edwards & Ehlmann, 2015; Ehlmann & Edwards, 2014; Ehlmann et al., 2008; Kelemen, Evans, et al., 2020; Salvatore et al., 2018; Tarnas et al., 2021; Tomkinson et al., 2013). References listed here are in addition to studies of carbon mineralization—forming completely carbonated “listvenites”—at the base of the Samail ophiolite mantle section and elsewhere on Earth, summarized in a companion paper to this one (Kelemen, de Obeso, Leong, & Godard, 2021) on OmanDP Hole BT1B, which sampled Cretaceous listvenites at the “leading edge of the mantle wedge,” which formed just above the basal thrus...…”

A Volcanological Paradox in a Thin-Section: Large Explosive Eruptions of High-Mg Magmas Explained Through a Vein of Silicate Glass in a Serpentinized Peridotite Xenolith (Hyblean Area, Sicily)

“…Such a conclusion is strengthened by the occurrence of 0.5-1.5 wt% strontium in both vein and vesicles carbonate, as revealed by microprobe analyses. This suggests an aragonite polytype, which is the typical carbonate mineralization in abyssal serpentinites, albeit outside its stability field [51].…”

“…Ni-rich sulfide (e.g., millerite-NiS: Reference [50]) and magnetite micrograins, as by-products of the serpentinization reactions [35,49], were evenly distributed along the serpentine veins. A further set of late-stage carbonate veins, either parallel or discordant with respect to the serpentinite veins, also occurred in the sample (Figure 3d; Reference [51]). [51]).…”

“…A further set of late-stage carbonate veins, either parallel or discordant with respect to the serpentinite veins, also occurred in the sample (Figure 3d; Reference [51]). [51]). (d) Microphotograph showing veins of secondary carbonate minerals postdating the serpentine veins and the silicate glass vein.…”

“…The veins generally consisted of two polytypes, chrysotile 2M c1 and lizardite 1T. Serpentine veins in the sample were coaxially intruded by a late vein of microcrystalline, Sr-bearing, low-Mg, Ca carbonate (likeky aragonite [51]). Ni-rich sulfide (e.g., millerite-NiS: Reference [50]) and magnetite micrograins, as by-products of the serpentinization reactions [35,49], were evenly distributed along the serpentine veins.…”