Characteristic directions and polarity ratings and polarity chron assignments of ODP Leg 171B sites

The full suite of magnetic polarity chrons from Subchron M''-2r'' (early Albian) through Chron C13r (latest Eocene) were resolved at one or more Ocean Drilling Program sites on the Blake Nose salient of the Florida continental margin. These sediments preserve diverse assemblages of calcareous and siliceous microfossils; therefore, the composite suite provides a reference section for high-resolution correlation of biostratigraphic datums to magnetic polarity chrons of the Late Cretaceous and Paleogene. Relative condensation or absence of polarity zones at different sites along the transect enhance the recognition and dating of depositional sequences and unconformities within the margin succession. A stable paleolatitude of ~25°N was maintained from the late Aptian through Eocene.

本数据集涵盖了从亚磁极性时M''-2r''（早阿尔布期）至磁极性时C13r（始新世最晚期）的全套磁极性时（magnetic polarity chrons）序列，该序列在佛罗里达大陆边缘布雷克鼻凸起（Blake Nose salient）处的一个或多个大洋钻探计划（Ocean Drilling Program）钻孔站位中得以厘定。这些沉积物保存了多样的钙质与硅质微古生物组合，因此该复合剖面可作为晚白垩世至古近纪生物地层界线点与磁极性时开展高分辨率对比的标准参考剖面。该剖面沿线不同站位的极性带存在相对凝缩或缺失的现象，有助于识别陆缘沉积序列中的沉积层序与不整合面并开展定年工作。从晚阿普第期至始新世，研究区域始终维持着约25°N的稳定古纬度。