摘要
广西上泥盆统斜坡—盆地相灰岩中存在着数量丰富、保存完好的磷质微球粒。其大小250μm±,球状、椭球状,部分微球粒表面具脐状或对称型脐状浅凹。在球切剖面上微球粒的球壳、球幔和球幔中的斑块分异清楚。显微激光拉曼光谱微区分析表明:球壳、球幔和球幔斑块的共有成分是磷、碳。特有成分铁主要存在于球幔斑块中。这种成分特征与动物卵细胞在成岩和后生过程中经脱水、脱羧、脱甲基、脱氨基和脱硫后的细胞膜、细胞质和细胞器的成分较为一致。球壳和球幔与牙形石属Palmatolepis sp.的齿片和齿台的显微激光拉曼光谱微区分析结果非常类似,说明二者的成分和物质结构有较大的亲缘性。我们认为这种磷质微球粒很可能是牙形石动物排出的卵细胞,球壳、球幔和球幔斑块可能分别代表卵细胞的细胞膜、细胞质和细胞器,类似于现今的鱼卵。脐状或对称型脐状浅凹可能代表卵细胞的动、植物极和以其为始端进行有丝分裂的开始。我们的资料不支持磷质微球粒为牙形石动物分泌的珍珠的推断。该发现对正确识别地层记录中微球粒的特征和成因,揭示牙形石动物的分类位置、繁殖、演化和绝灭提供了新的资料。
Abundant phosphatic microspherules preserved intactly have been found in the Upper Devonian slope-basin limestone. They are flattened or elliptical in shape and 250 μm± in diameter and have a lubricious surface. The crust, mantle and spots within the mantle show clearly in the equatorial section of microspherules. Laser Raman spectral studies show that the crust, mantle and spots within the mantle consist mainly of organic carbon and a-patite, and that hematite exists mainly in the spots within the mantle. The compositional characteristics are basically consistent with those of the oocyte's membrane, cytoplasm and cellular organelles that experienced dehydration, decarboxyl, decymene, deamido and desulfuration. There are strong similarities between the crust and mantle of a microspherule and the platform and blade of the conodont genus Palmatolepis sp. in Laser Raman spectral studies, which indicates their genetic relationships in composition and texture. The authors suggest that the phosphatic microspherules may be conodont animal oocytes. The crust, mantle and spots within the mantle of microspherules correspond to the oocyte's membrane, cytoplasm and cellular organelles, respectively, which is similar to fish spawn today.
出处
《地质学报》
EI
CAS
CSCD
北大核心
2001年第4期441-445,共5页
Acta Geologica Sinica
基金
国家自然科学基金(编号40072041)
国家"九五"攀登计划专项"SSER"项目的成果
