南海北部早第三纪涠洲组孢粉组合

 本文是北部湾东北部、雷州半岛、涠洲岛及海南岛北部十几口钻井中涠洲组 孢粉工作的总结。在涠洲组中共见113种孢粉类型，其中大部分为欧亚及北美 第三纪、尤其是渐新世孢粉区系成分，同时也出现加里曼丹岛渐新世-早中新世 区系的一些重要分子。这表明沉积时期本地区与加里曼丹岛有陆地相通或在地 理位置上较今日为近，植物能相互迁移。  印度第三纪孢粉区系与涠洲组区系相 似性拉少，仅出现少数相似类型(水蕨孢子、松科花粉)，说明虽然自印度次大陆 与欧亚大陆相遇后，这两地区的植物有了相互迁移的可能，但是直到渐新世，这 种迁移的规模还是很有限的，迁移到印度的植物所产生孢粉类型在印度发展的 高峰可能较欧亚大陆为晚。 从孢粉所反映的生态条件看，陆生及淡水植物多，而海产植物(如红树林)及 藻类很少。这说明当时北部湾可能为陆地，与雷州半岛等地连成一个内陆凹陷。 大量温带及山地针叶植物花粉及少量热带低地植物花粉的出现表明本地区附近 曾有大面积山地。    从孢粉组合上看，涠洲组形成的时代为渐新世。

Oligocene palynoflora in the northern part of South China sea

 In the northern part of South China Sea, including Tonkin Gulf, Hainan Island, Leizhou Peninsula and some basins of Guangdong Province, Oligocene deposits are com- posed of motley, mainly grey, greyish green and dark red clay and sandstone, containing very rich pollen and spores.  Most of them are of the components which exsisted in Tertiary, particularly in Oligocene deposits of Northern America and Eurasia, such as Gothanipollis paichanensis Ke & Shi, Ulmus granopollenites Rouse, Symplocos scabro- pollinia Traverse, Engelhardtia spackmaniana Traverse, etc.  At the same time some important Oligocene and Early Miocene pollen types of Borneo are found there, such as Crassoretitriletes vanraadshooveni Germeraad & al., Florschuetzia semilobata Ger- meraad & al., F. trilobata Germeraad & al., Magnastriatites howardi Germeraad & al., Jandufouria seamrogiformis Germeraad & al.,  Verrucatosporites usmansis  (Hammen) Germeraad & al., Margocolporites vanwijhci Germeraad & al., Psilatricolporites opercu- latus Hammen & Wymstra, Monoporites annulatus Hammen and Zonocostites sp., etc.      On the other hand in Oligocene palynoflora of Borneo there appear pollen types assigned to temperate plants or mountain plants of northern hemispherae (Pinus, Picea, Tsuga, Ephedra and Alnus), which are found in abundence in Oligocene palynoflara of the investigated area particularly in Late Oligocene.      All of this indicats that the palynoflora of the Northern part of South China Sea was closely related with that of Borneo in Oligocene.  This similarity of palyno- floras in the two localities may be due to the geographycal proximity of Borneo to the main land of Asia.      In paleoecological aspect, we have found there is plenty of pollen and spores of land and fresh water plants, while those reflecting  marine  and  coastal enviroments (Rhizophora and Sonneratia) are rather scanty.  This shows that in Oligocene period the investigated area was a land.  Tonkin Gulf along with Hainan Island and Leizhou Peninsula formed an inland depression at that time.      Abundant pollen of mountain plants and temperate plants indicats, that there weremountains in or around the area of interest.