摘要
中沙、西沙群岛海底 2 1个表层沉积样中发现微型腹足类 1 76种 ,微型双壳类 48种 ,形成 3个组合类型 :水深 0— 60m为Tricolia (Hiloa)variabilis Cadellasemitorta组合 ,水深 60— 1 2 0m为Cerithiopsis Ringicula Varicorbula组合 ,水深大于 80 0m为Anatomia Gastrochaena组合。腹足类、双壳类沉积组合包括原地埋藏和异地埋藏两种类型 ,而第二组合的异地埋葬分子显著增多 ,使其分异度和丰度均明显高于第一组合。第一组合为典型的热带动物群 ,而第二组合除热带动物群分子外 ,也出现较多的温带种类 ,但它们的分布深度显然比温带的同类深得多。比较Tricolia (Hiloa)variabilis和Cellana等典型热带分子的沉积分布与其活体生态分布的差异 ,发现水深约 2 0m ,50m 。
The micromoluscs including gastropods and bivalves dealt with in the present paper were collected from 21 sea bottom samples in water depth 20? ? 150m situated within the maritime space of the Xisha Islands and Zhongsha Islands of South Cina Sea (lat. 15°24′-17°08′N, long. 115°10′-114°57′E). The total biotaanalyses have revealed the aspects of distribution of the microgastropods and microbivalves. Microgastropods: A total of 176 species belonging to 39 families and 113 genera are identified. The most dominant species in surface sediments are Cellana nojimensis (Yokoyama), Cyclostrema porcellarium Tate et May, Tricolia (Hiloa) variabils (Pease), Liotia anulata Ten. Woods, Scaliola bella Adams, Scaliola glaresa Adams, Clathrofenella reticulata (Adams), Plesiotrochus acutangulus (Yokoyama), Bittium aleutaceum Gould, Diala stricta Habe, Rissoa beddomei Tate, Argyropeza divina Melvill and Standen, Cerithium (Therithium) elegantullum Gould, Triphora magica Feng, Orbitophora crassusicosta Yu et Feng, Odostomia didyma Verrill et Buch, Ringicula columnifera Yu et Feng, Ringicula (Ringiculina) teremachii Habe. Microbivalves: about 48 species assigned to 21 families and 40 genera are found. They are represented by such dominant species as Varicorbula rotalis (Hinds), Barbatia matsumotoi Habe, Paragrammatodon pacificus (Nomura et Zinbo), Philobrya (Hochstetterina) sp .,Septifer pulcher Wang, Septifer xishaensis Wang, Chama dunderi Lischke, Choniocardia (Carditellopsis) sp., Cadella semi torta (Reeve). Three assemblages have been distinguished in this region in the water depth of 20 —1150 m according to biota distribution and environmental factors: Assemblage I Tricolia (Hiloa) variabilis Cadella semitorta ,distributed in the water depth of 0—60 m ; Assemblage II Cerithiopsis Ringicula Varicorbula , in the water depth of 60—120 m; Assemblage III Anatomia Gastrochaena ,in the water depth of 800—1150 m. The temperature,water depth,substrates and sea bottom topography are regarded as the major environmental factors controlling the depositional distribution of the microgastropods and microbivalves in this region. As shown also by analyses,the biota in this region are composed of three types:the tidal or shallow water representatives of autochthonous deposit,deepwater representatives of autochthonous deposit and allochthonous deposit. The second assemblage contains relative richness of allochthonous deposit, which makes its diversity and abundance obviously higher than the first assemblage. Assemblage I is characterized by typical tropical animals while in Assemblage II, excepting tropical forms, there also occur some forms of temperate zone, but those forms of this region are distributed in maech deeper place than that of temperate zone. In comparison of the depositional distribution of the typical tropical forms, as Tricolia (Hiloa) variabilis and Cellana , with the ecological distribution of their living forms, it is found that the water depth of 20 m, 50 m and 90 m may have been three important interfaces implying three short stops of sea level since the Holocene.
出处
《古生物学报》
CAS
CSCD
北大核心
2000年第2期285-294,共10页
Acta Palaeontologica Sinica
基金
中国科学院古生物学与古人类学特别支持! ( 93 1 0 )基金资助课题
基金委特殊学科人才基金资助课题
关键词
腹足类
双壳类
沉积组合
环境意义
中沙群岛
Microgastropods, Microbivalves,Depositional assemblages,Environmental significance
