Low-temperature, diagenetic serpentinization of peridotite clasts in lower Miocene marine conglomerates, Torino Hill, NW Italy. (September 2022)

• Record Type: Journal Article
• Authors: Barale, L.; Petriglieri, J.R.; Botta, S.; Piana, F.
• Is Part Of: Marine and petroleum geology. Volume 143(2022)
• Publication Date: 2022-09
• Subjects: Low-T serpentinization -- Lizardite -- Peridotite -- Marine diagenesis -- Tertiary Piemonte basin; Submarine geology -- Periodicals; Petroleum -- Geology -- Periodicals; Géologie sous-marine -- Périodiques; Pétrole -- Géologie -- Périodiques; Petroleum -- Geology; Submarine geology; Periodicals; Electronic journals; 551.468
• DOI: 10.1016/j.marpetgeo.2022.105830
• Languages: English
• ISSNs: 0264-8172

Abstract

Abstract: Peridotite clasts in a marine Miocene conglomerate from the Torino Hill (NW Italy) are characterised by an isopachous serpentinized external rim (4–12 mm thick) made up of lizardite, surrounding a non-serpentinized peridotite core. This peculiar structure indicates a diagenetic, post-depositional serpentinization of the peridotite clasts. The conglomerate is cemented by a rim of lizardite, followed by Mg-calcite and Ca-dolomite spar. The burial history of the host sedimentary succession indicates that serpentinization and precipitation of lizardite cements probably occurred at very low temperature (max. 50–60 °C). This is the first reported case of diagenetic, very low temperature serpentinization affecting ultramafite clasts in sedimentary successions. Graphical abstract: Image 1 Highlights: Peridotite pebbles/cobbles with serpentinized rim (lizardite) in a Miocene conglomerate. Conglomerate is cemented by lizardite rims, followed by Mg-rich carbonates. Rim serpentinization is post-depositional. Geological evolution indicates a maximum burial depth of 1500 m, corresponding to 50–60 °C. Low-temperature, diagenetic serpentinization of peridotite clasts.