Correlation of burial organic carbon and paleoproductivity in the Mesoproterozoic Hongshuizhuang Formation, northern North China

Abstract

In general, total organic carbon (TOC) is directly used as a proxy for paleoproductivity, however, it is not only affected by paleoproductivity, but also controlled by redox conditions and terrigenous detrital matter influx. Major and trace elements were analysed with the purpose of investigating the redox potential and paleoproductivity during deposition of the Hongshuizhuang Formation. In the present study, C-S relationship, V/Cr ratio and Mo concentration indicate that the dolomites were deposited in oxic environments, however, most of the black shales were accumulated in euxinic environments. P/Ti values in the Hongshuizhuang samples can be compared with those in the Japanese Ubara Permian-Triassic section which were regarded to be deposited under a moderate to high paleoproductivity. Ba/Al values are slightly lower than that of the laminated sediments from the continental margins of Central California (CCAL) which were thought to be accumulated under a high paleoproductivity. These results indicate that the paleoproductivity was moderate to high during deposition of the Hongshuizhuang Formation. Burial organic carbon shows positive correlations with V/Cr and Mo, but shows only weakly or no correlation with P/Ti and Ba/Al, respectively, suggesting that although the paleoproductivity was moderate to high during deposition of the Hongshuizhuang Formation, its organic-rich sediments were predominantly controlled by redox conditions and had no direct relationship with paleoproductivity.

Late Quaternary environmental and climate changes registered in lacustrine sediments of the Serra Sul de Carajás, south‐east Amazonia

“…TOC gives insight into palaeoproductivity. However, it may not serve as an independent proxy for palaeoproductivity as it can be controlled by redox conditions and terrigenous influx (Luo et al ., ). Schnetger et al .…”

Trace element characterization of bitumen constraints on the hydrocarbon source of the giant gas field in Sichuan Basin, South China

“…The redox sensitive elemental ratios generally include V/Cr, Ni/Co, V/Ni, and Ni/Mo (Cao et al, ; Jones & Manning, ; López & Mónaco, ; López, Mónaco, Galarraga, Lira, & Cruz, ; Luo et al, ). The ionic potential of V and Cr, Ni and Co are close to each other (Railsback, ).…”

Geochemical characteristics of the Permian sedimentary rocks from Qiangtang Basin: Constraints for paleoenvironment and paleoclimate

“…In oxic environments, Mo is present as stable MoO 4 2-. Conversely, in anoxic environments, S 2-can replace O 2-in MoO 4 2-and become enriched in the sediments (Crusius et al 1996;Algeo and Maynard 2004;Luo et al 2013). Crusius et al (1996) suggested that 5 -40 μg g -1 Mo implies an , showing no enrichment tendency, which indicates that the samples were deposited in an oxic environment.…”

“…Paleoproductivity in a marine environment is controlled mainly by the availability of N and P (Holland 1978;Luo et al 2013;Zeng et al 2015). P is regarded as the ultimate limiting factor in marine environments and a major constituent of skeletal material and plays a fundamental role in many metabolic processes (Tyrrell 1999;Tribovillard et al 2006).…”