Branched and isoprenoid tetraether (BIT) index, TEX86 and sea surface temperatures of IODP Hole 302-M0004A

TEX86' rather than TEX86 was proposed to reconstruct SST for uppermost Paleocene strata of Core 302-4A-32X, as abundances of the glycerol dialkyl glycerol tetraether (GDGT) lipid containing three cyclopentanemoieties (GDGT-3) were unusually high. The TEX86' has the same definition as TEX86, except that isomer GDGT-3 was removed from the equation. For samples with normal GDGT distributions, TEX86 and TEX86' based temperatures were shown to be almost identical (Sluijs et al. 2006).

针对核心302-4A-32X上白垩纪地层，为重建稳定同位素温度（SST），提出了 TEX86' 模型以替代传统的 TEX86 模型，鉴于该地层中含三个环戊烯基团的甘油二烷基甘油四醚（GDGT-3）脂类的丰度异常偏高。TEX86' 与 TEX86 模型的定义相同，区别在于其方程式中排除了异构体 GDGT-3。对于GDGT分布正常的样本，基于 TEX86 和 TEX86' 模型的温度计算结果几乎完全一致（Sluijs et al. 2006）。