Geology, Petrology and O and H isotope geochemistry of remarkably 18O depleted Paleoproterozoic rocks of the Belomorian Belt, Karelia, Russia, attributed to global glaciation 2.4Ga

Geochemical and oxygen isotope signatures of mantle corundum megacrysts from the Mbuji-Mayi kimberlite, Democratic Republic of Congo, and the Changle alkali basalt, China

“…3b). Cr-rich ruby is rare and found worldwide in the Brazilian São Luiz alluvial deposit and in the Juina kimberlite (Hutchinson et al, 2001(Hutchinson et al, , 2004Watt et al, 1994), the Moses Rock Dike kimberlite in Utah (Padovani and Tracey, 1981), the metagabbros of Karelia in Russia (Bindeman and Serebryakov, 2011), and in the serpentinite at Hokitika in New Zealand (Grapes and Palmer, 1996); (a3) The field of sample CO3 is comparable to the chemical composition of ruby-bearing garnetite xenolith in garnet peridotite from Sulu terrane in China (Zhang et al, 2004).…”

Revealing the climate of snowball Earth from Δ 17 O systematics of hydrothermal rocks

“…Barite-and malachite-associated sulfate from a diamictite in Kaiyang, Guizhou, China, reveals meteoric water compositions of δ 18 O ≈ −34 ± 10‰, probably representing Marinoan meltwaters (7). Apart from chemical sediments (5,6) or ancient weathering products (7), it has also been suggested to estimate δ 18 O mw from hydrothermally altered rocks that have interacted with meltwater of meteoric origin (8).…”

“…Interaction of rocks with meteoric water at hydrothermal conditions (∼350°C) shifts δ 18 (8). At full equilibration, rocks have a δ 18 O r that is only 2-3‰ higher than the water they interacted with (12), but the degree of equilibration between a rock and a given water is generally unknown, compromising absolute δ 18 O mw estimates (8 (Fig.…”

“…At full equilibration, rocks have a δ 18 O r that is only 2-3‰ higher than the water they interacted with (12), but the degree of equilibration between a rock and a given water is generally unknown, compromising absolute δ 18 O mw estimates (8 (Fig. S1); a relation hereafter called meteoric water line (MWL).…”

“…The 18 O/ 16 O ratio of meteoric water (expressed as δ 18 O mw ) can serve as a proxy for paleotemperature if the hydrogeological context is known (4). A few attempts have been made to reconstruct ancient δ 18 O mw (5)(6)(7)(8).…”