Does burial diagenesis reset pristine isotopic compositions in paleosol carbonates?

Isotopic and micromorphological studies of Late Quaternary loess–paleosol sequences of the Karewa Group: Inferences for palaeoclimate of Kashmir Valley

“…Cerling et al, 1989;Quade et al, 1989bQuade et al, , 2004Rowe and Maher, 2000;Levin et al, 2004;Bera et al, 2010). The late Quaternary loessepaleosol sequences of Dilpur Formation of the Karewa Group are widely distributed in the Kashmir Valley.…”

Discriminating between tectonism and climate signatures in palustrine deposits: Lessons from the Miocene of the Teruel Graben, NE Spain

“…This may be due to the imprints of common meteoric diagenetic processes affecting these carbonates and causing the loss of primary signatures and homogenization of data (Alonso-Zarza, 2003 ). Similarly, Bera et al (2010 ) noted that burial diagenesis modified isotope signatures of Oligocene continental carbonates from the Himalayas, but that some of the initial signatures were preserved. Besides diagenesis, we should mention that most of the primary deposits examined here have been substantially reworked determining that the isotope composition of these palustrine deposits will reflect: the composition of the primary lacustrine deposition, the mixing of carbonate grains formed by different processes or sources (oncoids, intraclasts, bioclasts) and, obviously, the effects of pedogenesis and/or diagenesis.…”

Carbon isotopic evidence for organic matter oxidation in soils of the Old Red Sandstone (Silurian to Devonian, South Wales, UK)

“…Cerling 1984Cerling , 1991Cerling , 1992Driese et al 1992;Andrews et al 1995;Ekart et al 1999;Royer et al 2001;Bera et al 2010;Breecker et al 2010). This is because a high (palaeo-)atmospheric CO 2 contribution to soil zone gases can result in 13 C-rich calcretes, whereas high contributions from respired CO 2 (including oxidation of isotopically light vegetation) drive δ 13 C of pedogenic calcrete to lower values.…”

“…One might speculate that the late-stage spar of the Conigar Pit Sandstone Member exhibits less negative δ 18 O and δ 13 C values than the relatively older micritic nodules and void-lining microsparitic crystallaria (Figs 5a and 8) because the spar was less susceptible to oxygen isotopic alteration than the micrite. Based on examination of Oligocene terrestrial carbonates of the Himalayas, however, Bera et al (2010) considered that oxygen isotope compositions were best preserved in samples with over 70% micrite. They suggested that this was because the lowest water:rock ratios would normally be found in the most micritic samples.…”