Bulk composition of marine sediment cores MDBT 557 and MDBT 561 from the southern Brazilian continental shelf

This dataset contains grain-size distribution, total organic carbon (TOC), and bulk stable carbon isotope (δ¹³C-bulk) measurements from the Holocene marine sediment core MDBT 557 and MDBT 561, collected on the southern Brazilian continental shelf. Grain-size analyses were performed using laser diffraction after removal of carbonates and organic matter. TOC and δ¹³C-bulk were determined by elemental analysis–isotope ratio mass spectrometry (EA-IRMS) following acidification to remove inorganic carbon. The data provide information on sedimentological variability and bulk organic matter composition through the Holocene and are intended to support investigations of sediment dynamics, organic carbon burial, and paleoenvironmental changes on the southwestern Atlantic shelf.

本数据集包含采自巴西南部大陆架的两件全新世海洋沉积岩芯（MDBT 557、MDBT 561）的粒度分布、总有机碳（Total Organic Carbon, TOC）及整体稳定碳同位素（δ¹³C-bulk）测试数据。粒度分析采用激光衍射法完成，实验前需先去除碳酸盐与有机质；总有机碳与整体稳定碳同位素则经酸化去除无机碳后，采用元素分析-同位素比值质谱法（EA-IRMS）进行测定。本数据集提供了全新世以来的沉积学变化特征与整体有机质组成相关信息，可为西南大西洋陆架区域的沉积动力学、有机碳埋藏及古环境变化研究提供数据支撑。