Stratigraphic distribution of marine palynomorph species recorded for the Miocene of ODP Hole 105-645E (Table 1)

A total of 145 samples were analyzed for palynology, and all were found to be productive. Residues are dominated by pollen, terrestrial spores, and land plant tissues. Marine palynomorphs occur in all samples, which allowed us to recognize five Miocene dinocyst assemblage zones. Dinocyst assemblages indicate cool-water conditions and suggest a neritic rather than fully oceanic environment, with not only North Atlantic and Norwegian Sea affinities, but also containing both notable protoperidiniacean and possible endemic elements. Dinocyst assemblages indicate an early Miocene age for the bottom of Hole 645E and an age no younger than early late Miocene (Sample 105-645E-24R, CC) near the top of the interval studied. These age assignments provide an estimated initiation of ice rafting in Baffin Bay at between 7.4 and 9.5 Ma. Increased terrigenous influx and apparent disappearance of certain dinocyst taxa occur in the middle to late Miocene and may be related to oceanographic changes or climatic deterioration. Spores and pollen indicate a climate that varied within a temperate regime during the early and middle to early late Miocene, followed by climatic deterioration.
Four new dinocyst species are described: Batiacasphaera gemmata, Impletosphaeridium prolatum, Operculodinium vacuolatum, and Selenopemphix brevispinosa. The acritarch genus Cyclopsiella Drugg and Loeblich is emended, and two new combinations have been created: Cyclopsiella granosa (Matsuoka) and Cyclopsiella? laevigata (Chateauneuf). Cyclopsiella granosa (Matsuoka) n. comb. is considered a subjective junior synonym of Cyclopsiella granulata He and Li. Ascostomocystis granulatus Chateauneuf has been provisionally allocated to Cyclopsiella and renamed Cyclopsiella? chateauneufii. Two new acritarch species are described: Cyclopsiella spiculosa and Cymatiosphaera! baffinensis.

本研究共对145个样品开展孢粉学（palynology）分析，所有样品均成功获得可分析的孢粉类物质。样品残渣主要由花粉、陆生孢子与陆地植物组织构成。所有样品均产出海洋孢粉型（marine palynomorphs），据此我们识别出5个中新世沟鞭藻囊孢（dinocyst）组合带。沟鞭藻囊孢组合指示冷水环境，表明研究区为浅海而非远洋环境，其类群不仅具有北大西洋与挪威海的亲缘性，还包含显著的原多甲藻类（protoperidiniacean）类群及可能的特有分子。沟鞭藻囊孢组合显示645E钻孔（Hole 645E）底部的时代为中新世早期，研究层位顶部附近的105-645E-24R-CC号样品的时代不早于晚中新世早期。上述时代限定结果表明，巴芬湾（Baffin Bay）的冰筏沉积（ice rafting）起始时间约为7.4~9.5 Ma。中新世中晚期出现陆源输入增加及部分沟鞭藻囊孢类群的疑似消失事件，这可能与海洋学变化或气候恶化相关。孢子与花粉记录显示，中新世早期、中中新世至晚中新世早期，研究区气候处于温带波动状态，随后出现气候恶化。
本次研究描述了4个沟鞭藻囊孢新种：Batiacasphaera gemmata、Impletosphaeridium prolatum、Operculodinium vacuolatum及Selenopemphix brevispinosa。本研究修订了疑源类（acritarch）Cyclopsiella Drugg & Loeblich属，并建立2个新组合：Cyclopsiella granosa（Matsuoka）与Cyclopsiella? laevigata（Chateauneuf）。Cyclopsiella granosa（Matsuoka）新组合被视为Cyclopsiella granulata He & Li的主观晚出同物异名。Ascostomocystis granulatus Chateauneuf被暂时归入Cyclopsiella属，并重新命名为Cyclopsiella? chateauneufii。本次研究还描述了2个疑源类新种：Cyclopsiella spiculosa与Cymatiosphaera baffinensis。