This paper reports bulk organic carbon isotope data from a laboratory study designed to evaluate whether acid chromium reduction (ACR), commonly used to prepare rock/sediment samples for sulfur isotope analysis, significantly fractionates bulk organic carbon isotopes compared with the standard decarbonation (SD) method in Quaternary coastal plain incised valley sediments. In this study, 36 sediment samples obtained from a Quaternary sediment core from the Qiantang River incised valley on the East China coastal plain were tested. The results show differences in the δ¹³C_org values between the ACR and SD methods for Quaternary incised valley sediments ranging from – 0.97‰ to +0.34‰, with most values (86%) showing a negative bias. Approximately half of the samples yield δ¹³C_org values that differ by ≥ ± 0.3‰. The carbonate and total organic carbon (TOC) contents of the sediment samples have no significant effects on the bulk organic carbon isotopes derived by ACR. There is also no obvious correlation between the organic carbon loss by ACR and the difference of the δ¹³C_org values. We believe that ACR loses more ¹³C-enriched labile organic carbon and/or volatile organic compounds (VOCs) than SD, which leads to a negative bias in the δ¹³C_org values. The mineral composition was speculated to be related to a significant positive bias in the δ¹³C_org values by ACR observed in two particular samples and requires further study. Consequently, ACR should be used with caution for sediments containing primarily young labile organic carbon with medium to high TOC contents (TOC ≥ 0.5 wt %), as it may cause a large offset of the δ¹³C_org values compared with SD. However, ACR may be used for sediments containing organic matter primarily from terrestrial plants with relatively low TOC contents (TOC < 0.5 wt %).

本文报告了一项实验室研究中的大块有机碳同位素数据，该数据旨在评估通常用于制备岩石/沉积物样品以进行硫同位素分析的酸性铬还原（ACR）与标准脱碳（SD）相比是否能显着分离大块有机碳同位素。方法在第四纪沿海平原切开河谷沉积物。在这项研究中，对从华东沿海平原钱塘江切入谷第四纪沉积岩心中获得的36个沉积物样品进行了测试。结果表明在δ差异¹³ Ç_组织的ACR和SD方法第四纪切谷沉积物从之间的值- 0.97‰至+ 0.34‰，其中大部分的值（86％）表示负偏压。大约一半的样品产生δ ¹³C _org值相差≥±0.3‰。沉积物样品中的碳酸盐和总有机碳（TOC）含量对ACR衍生的整体有机碳同位素没有显着影响。还有由ACR有机碳损失和δ的差之间没有明显的相关性¹³ Ç_有机值。我们相信，ACR损失更大¹³ C-富集活性有机碳和/或挥发性有机化合物（VOC）低于SD，这导致在δ负偏压¹³ Ç_有机值。矿物组合物，推测在δ是相关的一个显著正偏压¹³ Ç_有机在两个特定样品中观察到的ACR值有待进一步研究。因此，ACR应谨慎使用含有介质主要年轻活性有机碳到高TOC含量（TOC≥0.5重量％）的沉积物，因为它可能会引起大的δ的偏移¹³ Ç_有机值与SD进行比较。但是，ACR可以用于主要来自陆生植物的有机物的沉积物，这些有机物的TOC含量相对较低（TOC <0.5 wt％）。