Biomarkers, stable carbon isotope record and pollen distribution of the soutwest African continental margin

This is part 2 of a study examining southwest African continental margin sediments from nine sites on a north-south transect from the Congo Fan (4°S) to the Cape Basin (30°S) representing two glacial (MIS 2 and 6a) and two interglacial stages (MIS 1 and 5e). Contents, distribution patterns, and molecular stable carbon isotope signatures of long-chain n-alkanes (C27-C33) and n-alkanols (C22-C32) as indicators of land plant vegetation of different biosynthetic types were correlated with concentrations and distributions of pollen taxa in sediments of the same time horizons. Selected single pollen type data reveal details of vegetation changes, but the overall picture is best illustrated by summing pollen known to predominantly derive from C4 plants or C4 plus CAM plants. The C4 plant signals in the biomarkers are recorded in the delta13C data and in the abundances of C31 and C33 n-alkanes, and the C32 n-alkanol. […]

本项研究为对西南非洲大陆边缘沉积物进行的考察的第二部分，该考察覆盖了从刚果扇区（4°S）至开普盆地（30°S）的九个地点，沿南北走向横跨，代表了两个冰川期（MIS 2 和 6a）以及两个间冰期（MIS 1 和 5e）。本研究通过分析长链正构烷烃（C27-C33）和正构烷醇（C22-C32）的组成、分布模式以及分子稳定碳同位素特征，这些特征作为不同生物合成类型陆地植被的指示指标，与同期沉积物中花粉类群的浓度与分布进行了相关性分析。所选单个花粉类型数据揭示了植被变化的细节，但整体图像的最佳呈现则需通过汇总已知主要源自C4植物或C4与CAM植物的花粉进行。生物标志物中的C4植物信号记录在δ13C数据以及C31和C33正构烷烃以及C32正构烷醇的丰度中。