Lower Cretaceous diatoms from ODP Leg 113 Site 693 (Weddell Sea) Part 2: Resting spores, chrysophycean cysts, an endoskeletal dinoflagellate, and notes on the origin of diatoms
Lower Cretaceous diatoms from ODP Leg 113 Site 693 (Weddell Sea) Part 2: Resting spores, chrysophycean cysts, an endoskeletal dinoflagellate, and notes on the origin of diatoms
复制标题
来自 ODP Leg 113 Site 693（威德尔海）的下白垩纪硅藻第 2 部分：休眠孢子、金藻包囊、内骨骼甲藻和硅藻起源注释
DOI：
--
复制
发表时间：
1990
期刊：
影响因子：
--
通讯作者：
R. Gersonde
中科院分区：
文献类型：
--
作者：
D. Harwood;R. Gersonde
第113航次在东南极威德尔海边缘的ODP 693站发现了丰富的下白垩统（下阿尔布统）硅质微体化石。该组合包括海洋硅藻、硅鞭藻、放射虫、藻类孢囊和内骨骼甲藻，它们保存得非常好，在大多数情况下，不包括放射虫，代表了这些群体中最古老的已知保存完好的组合。本章描述并举例说明了693 A孔和693 B孔中的下白垩纪硅藻休眠孢子、蓝藻孢囊和一种内骨骼甲藻。本文提出了6个硅藻新属和20个可能的硅藻休眠孢子新种，以及10个显然是新的蓝藻孢囊分类群和一个内骨骼甲藻种。本文和前一章（第一部分）中所报道的硅藻组合表明：（1）早白垩世晚期，硅藻是一个复杂、多样和分布广泛的类群;（2）随着更多数据的获得，硅藻群的高度足以预测一个有用的生物地层分带的构建;（3）这些Albian沉积物中的岩石组合与世界上已知的更年轻的Senonian岩石组合有很大的差异;（4）休眠孢子的形成和形成链的能力都是硅藻的古老特征;（5）早白垩世硅藻的分布可能仅限于大陆边缘和内海，在这些地区休眠孢子的形成是最常见的。因为这些组合是最古老的，保存完好的硅藻和金藻植物群已知的，本章的结论是一个简短的回顾和讨论的硅藻的起源，解决了休眠孢子的作用和假定的链接到金藻鞭毛虫。
A rich assemblage of Lower Cretaceous (lower Albian) siliceous microfossils was recovered at ODP Site 693 on the Weddell Sea margin of East Antarctica during Leg 113. This assemblage includes marine diatoms, silicoflagellates, radiolarians, Chrysophycean cysts, and endoskeletal dinoflagellates that are extraordinarily well preserved and in most cases, radiolarians excluded, represent the oldest known well-preserved assemblages of these groups. This chapter describes and illustrates Lower Cretaceous diatom resting spores, Chrysophycean cysts, and an endoskeletal dinoflagellate from Holes 693A and 693 B. Six new diatom genera and 20 new species of probable diatom resting spores are presented here, in addition to 10 apparently new Chrysophycean cyst taxa and one endoskeletal dinoflagellate species. Diatom assemblages reported here and in the preceding chapter on vegetative forms (Part 1) suggest: (1) that diatoms were a complex, diverse, and widespread group by late Early Cretaceous time; (2) that diversities are high enough to anticipate the construction of a useful biostratigraphic zonation as more data become available; (3) that there is a considerable difference between assemblages in these Albian sediments and younger Senonian diatomites known around the world; (4) that both resting spore formation and the ability to form chains are ancient features of the diatoms; and (5) that diatom distribution in the Early Cretaceous may have been restricted to continental margins and interior seas, areas where resting spore formation is most common. Because these assemblages are the oldest, well-preserved diatom and chrysophycean floras known, this chapter concludes with a brief review and discussion on the origin of the diatoms, addressing both the role of resting spores and postulated links to Chrysophycean flagellates.