Biotic and abiotic chemical weathering of siliciclastic sediments in cold environments

• Main Author: Floyd, Cansu
• Other Authors: Elwood Madden, Megan E., Soreghan, Gerilyn S., Elwood Madden, Andrew S., Karr, Elizabeth, Marra, Kristen R.
• Language: English
• Published: 2022
• Subjects: Geochemistry; Sedimentology; Geobiology; Planetary Science; Antarc*; Antarctica; Iceland
• Online Access: https://shareok.org/handle/11244/336972

Dissertation Summary Chemical weathering of silicate minerals is one of the most important Earth processes, moderating atmospheric carbon dioxide levels by consumption of carbon dioxide during hydrolysis of silicates (Nesbitt and Young, 1982; White and Peterson, 1990; Velbel, 1993; White and Blum, 1995; White et al., 1996; White and Brantley, 2003; White and Buss, 2014). Owing to its significance to the carbon cycle, and sensitivity to climatic conditions, chemical weathering and indices developed to determine the extent of weathering (i.e., Chemical Index of Alteration- CIA) have been the focus of significant studies aimed at investigating implications for paleoclimate in both terrestrial and extraterrestrial settings (i.e., Nesbitt and Young, 1982; Nesbitt and Young, 1989; Soreghan and Soreghan, 2007; Yang et al., 2016; Siebach et al., 2017; Deng et al., 2022). Chemical weathering leaves physical, chemical, and mineralogical signatures on rocks, sediments, and the aquatic environment, both via abiotic and biotic pathways. Therefore, weathering signatures studied on Earth are analogs for extraterrestrial signatures of surface alteration processes (i.e., Cannon et al., 2015; Olsson-Francis et al., 2017). However, abiotic and biotic weathering pathways in cold environments (i.e., within glacial settings) and subsequent weathering signatures remain poorly understood. This dissertation investigates biotic and abiotic weathering signatures and pathways within various glaciated settings, with the focus on Antarctica and Iceland as climatic and mineralogical analogs of Mars. Non-glaciated settings are also investigated to compare weathering signatures generated within cold and hot climates. Chapters within this dissertation are formatted as peer-reviewed journal publications (in prep. or published). The Chemical Index of Alteration (CIA) was developed to quantify the extent of weathering based on major oxides within silicates that are significantly associated with weathering: Al2O3, CaO, Na2O and K2O (Nesbitt and ...