Paleomagnetism of DSDP Leg 80 holes@en

Paleomagnetic results from sediments acquired from the continental margin at DSDP Sites 548, 549, 550, and 551 are described. Where possible, the results were used to construct a polarity reversal stratigraphy for the sections sampled, thus enabling the biostratigraphic dating of the sediments to be refined. Several sections in this study were found to be suitable for magnetostratigraphic work, in particular the upper Paleocene to middle Eocene sediments from Site 549, which contained rich faunal assemblages. These sediments are underlain by a thick sequence of Cretaceous sediments that formed during the Long Cretaceous normal polarity interval. Sediments that formed during the later part of this magnetically quiet interval were also recovered at Site 550. Three short reverse polarity intervals were also recovered at this site; they lie directly over basement and are thought to represent a mixed-polarity interval of late Albian age. They may therefore provide important evidence concerning the age of the earliest sediments at this site. […]本文记述了从深海钻探计划（Deep Sea Drilling Project, DSDP）548、549、550及551站位的大陆边缘沉积物中获取的古地磁研究结果。研究尽可能利用上述结果为所采样的剖面构建极性反转地层序列，从而实现沉积物生物地层年代学的精细化修正。本研究中的多个剖面被证实适用于磁地层学研究，其中尤以549站位的晚古新世至中始新世沉积物为代表，该套沉积物产出丰富的动物群组合。该套沉积物之下发育有厚层白垩纪沉积物，形成于漫长白垩纪正向极性间隔期。550站位同样采获了该磁静期后期形成的沉积物；该站位还发现三段短反向极性间隔，它们直接覆于基底之上，被认为代表阿尔布阶晚期的混合极性间隔。因此，这些间隔或可为该站位最早期沉积物的年代学研究提供重要佐证。[…]