Relationship between ²¹⁰Pbₑₓ activity and sedimentary organic carbon in sediments of 3 Chinese lakes

Xu, Libin; Wu, Fengchang; Wan, Guojiang; Liao, Haiqing; Zhao, Xiaoli; Xing, Baoshan

Relationship between ²¹⁰Pbₑₓ activity and sedimentary organic carbon in sediments of 3 Chinese lakes

2011

This report demonstrates that organic matter was an important factor in lake sediment ²¹⁰Pbₑₓ dating. Sediment cores from lakes in central and western China with different-trophic levels were collected, and the ²¹⁰Pbₑₓ activity and total organic carbon (TOC) were measured. The Rock-Eval pyrolysis technique was used to deconvolute TOC into free hydrocarbons (S1), thermally less-stable macromolecular organic matter (S2a), kerogen (S2b), and residual carbon (RC). The results show significant correlations between TOC and ²¹⁰Pbₑₓ, particularly between S2a and ²¹⁰Pbₑₓ, in all the sediment cores. This indicated that the algal-derived organic component S2a may play the most important role in controlling the distribution of ²¹⁰Pbₑₓ. Scavenging by algal-derived organic matter may be the main mechanism. As chronology is the key to the understanding of pollution reconstruction and early diagenesis in sediments, more attention should be paid to the influence of organic matter on ²¹⁰Pbₑₓ.

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