Pattern of δ¹³C_carb and implications for geological events during the Permian‐Triassic transition in South China

Abstract

Data from five marine sections across the Permian-Triassic boundary in southern China reveal a pattern of 13 Triassic). These complementary trends in strontium and carbon isotope data imply an extended period of enhanced continental uplift and weathering of silicates and organic matter across the PermianTriassic event boundary (PTEB). A pronounced sharp drop of d 13 C carb at the PTEB is most recognizable in the upper ramp environment of Meishan, occurs weakly in shallow water environments and cannot be discerned in the deepest water setting. We propose that this pattern reflects an enhancement of stratified-ocean conditions in the immediate aftermath of the latest Permian transgression. The sharp drop in d 13 C carb at the PTEB in the platform ramp environments likely resulted from the depth-selective calcification of 13 C-depleted dissolved inorganic carbon (DIC) formed by respiration of organic matter including, perhaps, methane. Indeed, massive volcanism at the PTEB would have enhanced eutrophication and stratification thereby slowing the mixing of 13 C-depleted DIC into deeper-water environments.

Carbon isotope stratigraphy of the basal Zechstein (Lopingian) strata in Northern Poland and its global correlation

“…At 258 Ma the d 13 C val ues de creased with an am pli tude of 0.9-1.5‰ to +3‰ (Iso tope Event 0 -Richoz et al, 2010) and then they in creased and re mained steady around a rel a tively high value of 4-5‰ for sev eral Ma un til a con sis tent, grad ual and pro gres sive de cline in d 13 C through late Changhsingian strata oc curred (Cao et al, 2010;Gaetani et al, 2009;Fig. 9A); this de cline be gan in the early Changhsingian at ca.…”

“…Carbon-iso tope ex cur sions are rec og nized in a wide range of ma rine and con ti nen tal de pos its; they rep re sent ma jor per tur ba tions of the global car bon cy cle and are of ten global events (e.g., Metcalfe et al, 2009;Cao et al, 2010;Bond et al, 2010;Richoz et al, 2010), al though changes in the d 13 C of car bon ate rocks of epeiric seas might not be re lated to vari a tions in the global or ganic car bon cy cle (e.g., Swart, 2008). Re gional strati graphic cor re la tion within the upper Perm ian Zechstein of cen tral and north-west Eu rope is rel atively straight for ward since sed i men ta tion through out the area fol lowed the clas si cal model of cy clic chem i cal pre cip i ta tion in a gi ant sa line ba sin.…”

Time-calibrated Milankovitch cycles for the late Permian

“…The section is correlated to Meishan with biostratigraphy and U–Pb dating12; the PTB is placed at the bed 28b/28c boundary12. The carbon isotope ( δ 13 C carb ) record at Shangsi is similar to that at Meishan and other sections12131617. The end-Permian mass extinctions are recorded in both sections121819.…”

Organic carbon isotope values from the Late Permian Seis/Siusi succession (Dolomites, Italy): Implications for palaeoenvironmental changes

“…1 ‰ positive excursion (Kraus et al 2009;Cao et al 2010) or a "plateau" ) interrupts the negative trend. Kraus et al (2009) used this chemostratigraphic marker, starting about 0.8 m above the base of the TOH in the Seis section (samples 53a; Fig.…”

“…Carbon isotope excursions, if global in scale, are usually traceable in carbonates and organic matter of marine and continental successions (ocean/atmosphere systems). This fact enables worldwide stratigraphic correlation of PTB successions (e.g., Cao et al 2010;Richoz et al 2010) as well as for several other stage boundaries, such as the Rhaetian-Hettangian (e.g., Hesselbo et al 2002;Korte et al 2009;Ruhl et al 2009) or Cenomanian-Turonian (e.g., Jarvis et al 2006;Sageman et al 2006).…”